Detour Lake Mine NI 43-101 Technical Report

Detour Lake Mine NI 43-101 Technical Report 31 January 2014

Detour Lake Mine NI 43-101 Technical Report

Table of Contents 1.0 

Executive Summary .............................................................................. 1-1 

1.1  1.2  1.3  1.4  1.5  1.6  1.7  1.8  1.9  1.10  1.11  1.12  1.13  1.14  1.15  1.16 

Introduction ......................................................................................................... 1-1  Property Description and Location ..................................................................... 1-2  Geology and Mineralization ................................................................................ 1-2  Exploration and Drilling Activities ....................................................................... 1-3  Drilling, Quality Control, and Data Verification ................................................... 1-3  Mineral Processing and Metallurgical Testing .................................................... 1-3  Mineral Resources ............................................................................................. 1-6  Mineral Reserves ............................................................................................... 1-7  Mining Methods .................................................................................................. 1-8  Recovery Methods ............................................................................................. 1-8  Project Infrastructure .......................................................................................... 1-9  Environmental and Aboriginal Matters ............................................................. 1-10  Capital and Operating Costs ............................................................................ 1-12  Economic Analysis ........................................................................................... 1-13  Interpretations and Conclusions ....................................................................... 1-15  Recommendations ........................................................................................... 1-16 

2.0 

Introduction ........................................................................................... 2-1 

2.1  2.2  2.3 

Purpose and Terms of Reference ...................................................................... 2-1  Units and Currency ............................................................................................. 2-1  Inspection of Property ........................................................................................ 2-1 

3.0 

Reliance on Other Experts ................................................................... 3-1 

3.1 

Disclaimer ........................................................................................................... 3-1 

4.0 

Property Description and Location ..................................................... 4-1 

4.1  4.2  4.3  4.4  4.5 

Location and Access .......................................................................................... 4-1  Property Ownership and Agreements ................................................................ 4-1  Summary of NSR or Other Obligations .............................................................. 4-4  Current Environmental Obligations .................................................................... 4-4  Permits in Place ................................................................................................. 4-5 

5.0 

Accessibility, Climate, Local Resources, Infrastructure, and Physiography ........................................................................................ 5-1 

5.1.1  Accessibility .................................................................................................. 5-1  5.2  Climate and Physiography ................................................................................. 5-1  5.3  Local Resource and Infrastructure ..................................................................... 5-1 

6.0 

History ................................................................................................... 6-1 

6.1 

Ownership History .............................................................................................. 6-1 

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6.2  Exploration History ............................................................................................. 6-2  6.3  Previous Mineral Resource and Reserve Estimates .......................................... 6-4  6.3.1  Detour Lake .................................................................................................. 6-4  6.3.2  Block A ......................................................................................................... 6-7 

7.0 

Geological Setting and Mineralization ................................................ 7-1 

7.1  7.2  7.3  7.4  7.5  7.5.1  7.5.2  7.5.3 

Regional Geology ............................................................................................... 7-1  Detour Lake Mine and Block A Stratigraphy....................................................... 7-6  Metamorphism and Alteration ............................................................................ 7-9  Structural Geology ............................................................................................ 7-10  Mineralization ................................................................................................... 7-11  General Characteristics of the Gold Mineralization .................................... 7-11  Gold Mineralization at the Detour Lake Mine ............................................. 7-12  Gold Mineralization at the Block A Deposit ................................................ 7-14 

8.0 

Deposit Types ....................................................................................... 8-1 

9.0 

Exploration ............................................................................................ 9-1 

9.1  Background ........................................................................................................ 9-1  9.1.1  MMI Geochemical Surveys ........................................................................... 9-1  9.1.2  IP Geophysical Surveys ............................................................................... 9-1  9.1.3  Geological Field Mapping and Interpretation ................................................ 9-1 

10.0  Drilling Programs ................................................................................ 10-1  10.1  10.2  10.3  10.4  10.5  10.6 

Detour Lake Deposit ......................................................................................... 10-2  Block A Deposit ................................................................................................ 10-3  Exploration Drilling Programs ........................................................................... 10-3  Other Drilling Programs .................................................................................... 10-4  Drill Hole Survey and Drill Core Recovery........................................................ 10-4  Mine Grid .......................................................................................................... 10-6 

11.0  Sample Preparation, Analyses, and Security ................................... 11-1  11.1  Core Sampling Procedures and Securities....................................................... 11-1  11.2  Analytical Laboratories ..................................................................................... 11-3  11.3  Sample Preparation and Analysis .................................................................... 11-4  11.3.1  Sample Preparation and Analysis for Historic Data .................................... 11-4  11.3.2  Sample Preparation .................................................................................... 11-4  11.3.3  Gold Analysis for Detour Lake .................................................................... 11-5  11.3.4  Gold Analysis for Block A ........................................................................... 11-6  11.3.5  Gold Analysis for Regional Exploration ...................................................... 11-6  11.4  Specific Gravity ................................................................................................ 11-7  11.5  Quality Assurance and Quality Control Procedure ........................................... 11-8  11.5.1  QA/QC Procedures Prior to 2007 ............................................................... 11-8  11.5.2  QA/QC Procedures from 2007 to 2011 ...................................................... 11-9  11.5.3  QA/QC Procedures for Block A Prior to 2012 ........................................... 11-10  ii

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Detour Lake Mine NI 43-101 Technical Report

11.5.4  QA/QC Procedures for Block A in 2012 ................................................... 11-11  11.6  Conclusion ...................................................................................................... 11-19 

12.0  Data Verification ................................................................................. 12-1  12.1  Drill Hole Database Verification ........................................................................ 12-1  12.2  Database Verification of Historic and Detour Gold Drill Hole Data ................... 12-1  12.2.1  Kallio 2005 – 2006 Verification Program .................................................... 12-1  12.2.2  Scott Wilson RPA 2009 Database Verification Program ............................ 12-2  12.3  SGS Geostat 2009 Database Verification Program ......................................... 12-4  12.4  SGS Geostat 2010 Database Verification Program ......................................... 12-5  12.5  SGS Geostat 2011 Database Verification Program ......................................... 12-6  12.6  SGS Geostat 2012 Detour Drill Hole Database Verification Program .............. 12-6  12.7  Final Drill Hole Database ................................................................................ 12-11  12.8  Summary and Recommendations .................................................................. 12-13 

13.0  Mineral Processing and Metallurgical Testing ................................. 13-1  13.1  Sample Selection and Preparation ................................................................... 13-1  13.2  Comminution Test Work ................................................................................... 13-1  13.2.1  Circuit Simulation........................................................................................ 13-2  13.3  Metallurgical Test Work .................................................................................... 13-3  13.4  Recovery Estimates ......................................................................................... 13-8  13.5  Estimated Recovery for the Life of Mine......................................................... 13-11  13.6  Update of Recovery Model ............................................................................. 13-12  13.7  Comparison CIP versus CIL ........................................................................... 13-13  13.8  Modeling Carbon-in-Pulp (CIP) ...................................................................... 13-13  13.9  Thickening and Rheology ............................................................................... 13-13  13.10  Cyanide Destruction ....................................................................................... 13-13  13.11  Reagents ........................................................................................................ 13-14  13.12  Selected Process ........................................................................................... 13-15  13.13  Metallurgical Testing on Block A .................................................................... 13-16  13.13.1  2010 Metallurgical Test Work ................................................................... 13-16  13.13.2  2012-2013 Comminution and Metallurgical Test Work ............................. 13-17  13.14  Conclusion ...................................................................................................... 13-21 

14.0  Mineral Resource Estimates .............................................................. 14-1  14.1  Introduction ....................................................................................................... 14-1  14.2  Detour Lake Mine Resource Estimates ............................................................ 14-3  14.2.1  Detour Lake Mine Data............................................................................... 14-3  14.2.2  Detour Lake Mine Geological Interpretation ............................................... 14-3  14.2.3  Detour Lake Mine Capping ......................................................................... 14-5  14.2.4  Detour Lake Mine Composites ................................................................... 14-8  14.2.5  Detour Lake Mine Spatial Analysis ........................................................... 14-10  14.2.6  Detour Lake Mine Resource Block Modeling ........................................... 14-11  4 February 2014

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14.2.7  Detour Lake Mine Block Grade Interpolation ............................................ 14-14  14.2.8  Detour Lake Mine Mineral Resources Classification ................................ 14-20  14.2.9  Detour Lake Mine In-Pit Mineral Resources ............................................. 14-21  14.3  Block A Resource Estimate ............................................................................ 14-23  14.3.1  Block A Data ............................................................................................. 14-23  14.3.2  Block A Geological Interpretation ............................................................. 14-24  14.3.3  Block A Capping ....................................................................................... 14-25  14.3.4  Block A Composites ................................................................................. 14-28  14.3.5  Block A Spatial Analysis ........................................................................... 14-29  14.3.6  Block A Resource Block Modeling ............................................................ 14-31  14.3.7  Block A Block Grade Interpolation ............................................................ 14-33  14.3.8  Block A Mineral Resource Classification .................................................. 14-37  14.3.9  Block A In-Pit Mineral Resources ............................................................. 14-39 

15.0  Mineral Reserve Estimates ................................................................ 15-1  15.1  Reserve Block Model ....................................................................................... 15-2  15.2  Pit Optimization ................................................................................................ 15-2  15.2.1  Grade Data ................................................................................................. 15-3  15.2.2  General Pit Slope ....................................................................................... 15-3  15.2.3  Mining Dilution ............................................................................................ 15-3  15.2.4  Costs and Gold Price.................................................................................. 15-3  15.2.5  Mill Recovery .............................................................................................. 15-3  15.2.6  Mill Cut-off Grade ....................................................................................... 15-4  15.3  Pit Optimization Results ................................................................................... 15-5  15.4  Engineered Pit Design Parameters .................................................................. 15-5  15.4.1  Geotechnical Considerations and Bench Configuration ............................. 15-5  15.4.2  Final Ramp Design ..................................................................................... 15-7  15.5  Pit Design Results ............................................................................................ 15-8  15.6  Mining Dilution and Mining Loss Evaluation ..................................................... 15-9  15.7  Reserve Statement ........................................................................................... 15-9 

16.0  Mining Methods .................................................................................. 16-1  16.1  Introduction ....................................................................................................... 16-1  16.2  Mine Production Plan ....................................................................................... 16-1  16.2.1  Annual Mine Plan Results .......................................................................... 16-1  16.2.2  End-of-Period Mine Production Plans 2012 – 2035 ................................... 16-5  16.2.3  Overburden and Waste Rock Disposal Areas .......................................... 16-21  16.2.4  Mineralized Waste Stockpile .................................................................... 16-23  16.3  Mining Equipment Selection ........................................................................... 16-23  16.3.1  Primary Equipment Operating Times ....................................................... 16-24  16.3.3  Equipment Availability and Utilization ....................................................... 16-25  16.3.5  Drilling....................................................................................................... 16-26  16.3.7  Blasting ..................................................................................................... 16-27  16.3.8  Loading ..................................................................................................... 16-28  16.3.10  Hauling ..................................................................................................... 16-29  iv

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Detour Lake Mine NI 43-101 Technical Report

16.3.11 

Maintenance and Repair Contract ............................................................ 16-30 

17.0  Recovery Methods .............................................................................. 17-1  17.1  Process Plant Design ....................................................................................... 17-1  17.2  Process Plant 2013 Results ............................................................................. 17-1  17.3  Process Plant LOM Forecast............................................................................ 17-4  17.4  Debottlenecking ................................................................................................ 17-6  17.5  Tailings and Water Management.................................................................... 17-11  17.5.1  TMA Design Criteria and Deposition Plan (feasibility study) .................... 17-12  17.5.2  Design of TMA Dams ............................................................................... 17-13  17.5.3  TMA Water Management ......................................................................... 17-15  17.5.4  Geotechnical Design of the Mine Rock and Overburden Stockpiles ........ 17-18  17.5.5  Mine Rock Stockpiles ............................................................................... 17-18  17.5.6  Overburden Stockpiles ............................................................................. 17-18  17.5.7  Performance Monitoring ........................................................................... 17-18 

18.0  Infrastructure ...................................................................................... 18-1  18.1  Site Resources and Infrastructure .................................................................... 18-1  18.1.1  Site Accommodations ................................................................................. 18-1  18.1.2  Power Supply ............................................................................................. 18-1  18.1.3  Water Supply .............................................................................................. 18-1  18.1.4  Processing Plant Facilities .......................................................................... 18-1  18.1.5  Tailings Management Area ......................................................................... 18-2  18.1.6  Waste Rock Facility .................................................................................... 18-2  18.1.7  Mineralized Waste ...................................................................................... 18-3  18.1.8  Overburden Stockpiles ............................................................................... 18-3  18.1.9  Explosives Plant ......................................................................................... 18-3  18.1.10  Mine Service Facility................................................................................... 18-3  18.1.11  Site Roads .................................................................................................. 18-3  18.1.12  Site Communications.................................................................................. 18-4  18.1.13  Site Security ............................................................................................... 18-4  18.2  Cochrane Facilities ........................................................................................... 18-4 

19.0  Market Studies and Contracts ........................................................... 19-1  20.0  Environmental Studies, Permitting and Social or Community Impact .................................................................................................. 20-1  20.1  Environmental Studies and Permitting ............................................................. 20-1  20.1.1  Existing Environmental Conditions ............................................................. 20-1  20.1.2  Environmental Approval Requirements for Proposed Operations .............. 20-1  20.2  Environmental Impacts and Mitigating Measures ............................................. 20-4  20.2.1  Air Quality and Noise .................................................................................. 20-4  20.2.2  Geology and Geochemistry ........................................................................ 20-4  20.2.3  Groundwater ............................................................................................... 20-7  20.2.4  Surface Water............................................................................................. 20-7  20.2.5  Vegetation and Wildlife ............................................................................... 20-8  4 February 2014

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20.2.6  Aquatic Resources ..................................................................................... 20-8  20.2.7  Cultural and Heritage Resources ............................................................... 20-9  20.3  Social and Community Impact .......................................................................... 20-9  20.4  Closure and Reclamation Planning and Costs ............................................... 20-10  20.4.1  Estimated Mine Closure Costs ................................................................. 20-12 

21.0  Capital and Operating Costs .............................................................. 21-1  21.1  Sustaining Capital Costs .................................................................................. 21-1  21.2  Deferred Stripping ............................................................................................ 21-3  21.3  Operating Costs ............................................................................................... 21-3  21.4  Mining Operating Costs .................................................................................... 21-4  21.5  Processing Costs ............................................................................................. 21-5  21.5.1  Plant Operating Manpower ......................................................................... 21-6  21.5.2  Plant Electricity Costs ................................................................................. 21-6  21.5.3  Plant Consumables Costs .......................................................................... 21-7  21.5.4  Process Plant Maintenance Costs .............................................................. 21-7  21.6  General and Administration Costs .................................................................... 21-8  21.7  Commercial Production .................................................................................... 21-8 

22.0  Economic Analysis ............................................................................. 22-1  22.1  Economic Analysis ........................................................................................... 22-1  22.1.1  Assumptions ............................................................................................... 22-1  22.1.2  Taxation ...................................................................................................... 22-1  22.1.3  Discount Rate ............................................................................................. 22-3  22.1.4  Summary of Assumptions ........................................................................... 22-4  22.1.5  Mine Closure .............................................................................................. 22-4  22.1.6  Base Case Cash Flow ................................................................................ 22-4  22.1.7  Sensitivity Analysis ..................................................................................... 22-5  22.1.8  Optimization of the Detour Lake mine’s Economics ................................... 22-6 

23.0  Adjacent Properties ............................................................................ 23-1  24.0  Other Relevant Data and Information................................................ 24-1  24.1  24.2  24.3  24.4  24.5 

Operational Information .................................................................................... 24-1  Operational Results .......................................................................................... 24-2  Optimization Information .................................................................................. 24-4  Advanced Projects ........................................................................................... 24-5  Exploration ....................................................................................................... 24-7 

25.0  Interpretation and Conclusions ......................................................... 25-1  25.1  25.2  25.3  25.4  25.5  vi

Introduction ....................................................................................................... 25-1  Geology ............................................................................................................ 25-1  Drilling, Sampling, Data Verification ................................................................. 25-1  Mineral Resource Estimate .............................................................................. 25-2  Mineral Reserves and Mine Operations ........................................................... 25-2  4 February 2014

Detour Lake Mine NI 43-101 Technical Report

25.6  25.7  25.8  25.9  25.10  25.11 

Mine Plan ......................................................................................................... 25-3  Metallurgical Test Work .................................................................................... 25-3  Plant Operations and Tailing Management ...................................................... 25-3  Sustaining and Operating Costs ....................................................................... 25-4  Economic Analysis and Sensitivity ................................................................... 25-4  Conclusion ........................................................................................................ 25-4 

26.0  Recommendations .............................................................................. 26-1  26.1  26.2  26.3  26.4  26.5  26.6 

Mining Operations ............................................................................................ 26-1  Gold Recovery .................................................................................................. 26-1  Mineral Reserves ............................................................................................. 26-1  Drilling, Sampling, and Data Verification .......................................................... 26-2  Block A Project ................................................................................................. 26-2  Exploration ....................................................................................................... 26-2 

27.0  References .......................................................................................... 27-1  28.0  QP Certificates .................................................................................... 28-1  Appendix A 

List of Claims / Claim Map .................................................. A-1 

Appendix B 

ASL Report (L. Bloom, March 17, 2013) ............................ B-1 

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Detour Lake Mine NI 43-101 Technical Report

List of Tables Table 1-1  Table 1-2  Table 1-3  Table 1-4  Table 1-5  Table 4-1  Table 4-2  Table 6-1  Table 6-2  Table 6-3  Table 6-4  Table 6-5  Table 6-6  Table 6-7  Table 6-8  Table 6-9  Table 10-1  Table 10-2  Table 11-1  Table 11-2  Table 11-3  Table 11-4  Table 11-5  Table 11-6  Table 11-7  Table 12-1  Table 12-2  Table 12-3  Table 12-4  Table 12-5  Table 13-1  Table 13-2  Table 13-3  Table 13-4  Table 13-5 

4 February 2014

Summary Mineral Resource1, 2, 3, 4, 5 Effective December 31, 2013 .................... 1-7  Detour Lake Mine Mineral Reserves1, 2, 3, 4, 5 Effective December 31, 2013 ....... 1-8  Summary of Sustaining Capital Cost Estimate ................................................. 1-12  LOM Total Cash Costs ...................................................................................... 1-13  Sensitivity Analysis ........................................................................................... 1-15  Summary of the Detour Lake Property ............................................................... 4-2  NSR Obligations.................................................................................................. 4-4  Summary of Mineral Resource History ............................................................... 6-4  September 2009 Mineral Reserve Estimate (using US$775/oz gold price and a cut-off grade of 0.60 g/t Au , ..................................................................... 6-5  May 2010 Global Mineral Resource Estimate (cut-off grade of 0.50 g/t Au)2, 3, , ............................................................................................................... 6-5  May 2010 Mineral Reserve Estimate (using US$850/oz gold price and a cut-off grade of 0.50 g/t Au)2, 3 ............................................................................ 6-5  January 2011 Global Mineral Resource Estimate (cut-off grade of 0.50 g/t Au)2, 3, 4, 5 ............................................................................................................. 6-6  January 2011 Mineral Reserves Estimate (using US$850/oz gold price and a cut-off grade of 0.50 g/t Au)2, 3 ......................................................................... 6-6  2011 Year-end Global Mineral Resource Estimate (using a cut-off grade of 0.5 g/t Au)2, 3, 4, 5 .................................................................................................. 6-7  2011 Year-end Mineral Reserve (using US$850/oz gold price and a cut-off grade of 0.50 g/t Au)2, 3 ....................................................................................... 6-7  February 2011 Block A In-pit Mineral Resource Estimate (using US$1,000/oz gold price and a cut-off grade of 0.50 g/t Au)4, 5............................ 6-7  All Historical and Recent Drilling on the Property ............................................. 10-1  Technical Drilling on the Detour Lake and Block A Properties ......................... 10-4  Detour Gold Analytical Methods from 2007 to 2012 ......................................... 11-5  Mine Rock Codes and Mean Density (t/m3) ...................................................... 11-7  Summary of Reference Materials with Trade Winds Samples (2012) ............ 11-11  Summary of Reference Materials with Detour Gold Samples (2012) ............. 11-12  Summary of Gold Assays for Drill Core Duplicates ........................................ 11-16  Comparison of Gold by Fire Assay and Screen Metallics (selected on the basis of visible gold) ........................................................................................ 11-17  Comparison of Gold by Fire Assay and Screen Metallics (selected on the basis of Original Fire Assay Au > 5 g/t) .......................................................... 11-18  Comparative Statistics for the 2012 Check Sampling Results (Detour Gold) .. 12-8  2012 Check Sampling Sign Test Results (Detour Gold) .................................. 12-8  Comparative Statistics for the 2012 Fire Assay Check Sampling Results (Trade Winds) ................................................................................................. 12-10  Check Sampling Sign Test Results (Trade Winds)......................................... 12-10  Detour Lake Drilling Data Included in the Final Resource Estimation Drill Hole Database ................................................................................................ 12-12  Comminution Test Statistics ............................................................................. 13-2  Process Design Basis ....................................................................................... 13-3  Comparisons Between Different Methodologies for Power (@ pinion) and Mill Sizing Calculation for a SABC Circuit ......................................................... 13-3  Tail versus Gold Head Grade (BBA Tail Model) ............................................... 13-9  Updated Equation Used in the Pre-Feasibility Study and Feasibility Study Block Models and Mining Plans ...................................................................... 13-10  ix

List of Tables

Table 13-6  Table 13-7  Table 13-8  Table 14-1  Table 14-2  Table 14-3  Table 14-4  Table 14-5  Table 14-6  Table 14-7  Table 14-8  Table 14-9  Table 14-10  Table 14-11  Table 14-12  Table 14-13  Table 14-14  Table 14-15  Table 14-16  Table 14-17  Table 14-18  Table 14-19  Table 14-20  Table 14-21  Table 14-22  Table 14-23  Table 15-1  Table 15-2  Table 15-3  Table 15-4  Table 16-1  Table 16-2  Table 16-3  Table 16-4  Table 16-5  Table 16-6  Table 16-7  Table 16-8  Table 16-9  Table 16-10  Table 16-11  Table 17-1  x

Comparison Between BBA (Tail Model) and Previous Model ........................ 13-11  Reagent Consumption Summary (Thickening, Cyanidation, and Cyanide Destruction) ..................................................................................................... 13-15  Comminution Test Result Comparison between Detour Lake and Block A .. 13-19  Detour Gold Mineral Resources1, 2, 3, 4, 5 Effective December 31, 2013 ............ 14-2  Summary of Database ...................................................................................... 14-3  Detour Lake Drill Hole Assay Intervals with Gold Values above 300 g/t ......... 14-5  Detour Lake Capping Limits for GTs of Original Sample in 2011 Data ........... 14-6  Capping Limits for GTs of Original Sample Added to 2013 Data ..................... 14-7  Detour Lake Statistics of 5 metre Uncapped and Capped 2011 and 2013 Composite Grades only for Affected Domains.................................................. 14-8  Detour Lake Statistics of 5 metre Uncapped and Capped 2011 Composite Grades for Unchanged Domains ...................................................................... 14-9  Detour Lake Variogram Models of 5 metre Composites in the Mineralized Domains .......................................................................................................... 14-10  Detour Lake Resource Block Model Parameters (edges) .............................. 14-12  Detour Lake Volumetric of 10 x 5 x 12 metre Blocks by Domain and Total ... 14-12  Detour Lake Block Model Estimation Parameters .......................................... 14-15  Detour Lake Statistics of Block Grade Estimates from the Various Interpolation Runs ........................................................................................... 14-16  Base Case Pit Optimization Parameters ........................................................ 14-22  Detour Lake Mine Mineral Resources1, 2, 3, 4, 5 Effective December 31, 2013 . 14-23  Block A Database Summary ........................................................................... 14-24  Block A Drill Hole Assay Intervals with Gold Values above 300 g/t................ 14-26  Block A Capping Limits for GTs of Original Sample Data .............................. 14-27  Block A Statistics of Uncapped and Capped Composite Data (5 m) Totaled by Domain ....................................................................................................... 14-28  Block A Variogram Models of 5 metre Composites per Mineralized Domains .......................................................................................................... 14-30  Block A Resource Block Model Parameters (edges) ...................................... 14-32  Block A Block Model Estimation Parameters.................................................. 14-34  Block A Statistics of Block Grade Estimates from the Various Interpolation Runs ................................................................................................................ 14-35  Block A Mineral Resources1, 2, 3, 4, 5 Effective December 31, 2013 ................. 14-39  Detour Lake Mine Mineral Reserves1, 2, 3, 4, 5 Effective December 31, 2013 .... 15-1  Cost Summary Used for Pit Optimization ......................................................... 15-3  Mill Cut-Off Grade Calculation .......................................................................... 15-4  Mineral Reserves Estimate using a Cut-off Grade of 0.50 g/t Au (including 4.0% dilution at 0.20 g/t Au and 5% ore loss) ................................................... 15-9  Detour Lake Project 61,000 tpd Mine Production Plan with Dilution and Ore Loss ................................................................................................................... 16-4  Shift Parameters and Net Productive Operating Hours .................................. 16-24  Mechanical Availability and Utilization ............................................................ 16-25  Drilling Specifications ...................................................................................... 16-26  Blasting Specifications .................................................................................... 16-27  Loading Specifications .................................................................................... 16-28  Haulage Distance Template for each Material Type....................................... 16-29  Truck Speed Assumptions .............................................................................. 16-29  Primary and Support Fleet GOH ..................................................................... 16-31  Annual Mining Fleet Requirements ................................................................. 16-32  Mining Fleet Replacement Schedule .............................................................. 16-33  Process Plant Throughput Average Rates ....................................................... 17-1  4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Table 17-2  Table 17-3  Table 20-1  Table 20-2  Table 20-3  Table 21-1  Table 21-2  Table 21-3  Table 21-4  Table 21-5  Table 21-6  Table 21-7  Table 21-8  Table 21-9  Table 22-1  Table 22-2  Table 22-3  Table 24-1 

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Process Plant Average Throughput Rates ....................................................... 17-4  Projected Reagent Consumption Rates (kg/t) .................................................. 17-5  Federal Environmental Approvals ..................................................................... 20-2  Provincial Environmental Approvals ................................................................. 20-3  Security Bonding Arrangements ..................................................................... 20-12  LOM Key Parameters ....................................................................................... 21-1  Summary of Sustaining Capital Cost Estimate ................................................. 21-1  LOM Economic Assumptions ............................................................................ 21-3  LOM Total Cash Costs ...................................................................................... 21-4  LOM Estimated Mining Costs ........................................................................... 21-4  LOM Estimated Process Plant Costs ................................................................ 21-6  LOM Estimated Plant Consumable Costs ........................................................ 21-7  LOM Estimated Plant Maintenance Costs ........................................................ 21-7  LOM Estimated General and Administration Costs .......................................... 21-8  Technical Assumptions ..................................................................................... 22-4  Simplified Cash Flow on an Annual Basis (after tax) ........................................ 22-5  Sensitivity Analysis ........................................................................................... 22-6  Block A Pre-Feasibility Study Requirements .................................................... 24-6 

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Detour Lake Mine NI 43-101 Technical Report

List of Figures Figure 4-1  Figure 4-2  Figure 7-1  Figure 7-2  Figure 7-3  Figure 7-4  Figure 7-5  Figure 7-6  Figure 10-1  Figure 10-2  Figure 11-1  Figure 11-2  Figure 11-3  Figure 11-4  Figure 11-5  Figure 12-1  Figure 12-2  Figure 13-1  Figure 13-2  Figure 13-3  Figure 13-4  Figure 13-5  Figure 13-6  Figure 13-7  Figure 13-8  Figure 14-1  Figure 14-2  Figure 14-3  Figure 14-4  Figure 14-5  Figure 14-6  Figure 14-7  Figure 14-8  Figure 14-9  Figure 14-10  Figure 14-11 

4 February 2014

Detour Lake Property Location ........................................................................... 4-1  Detour Lake Property Claim Location Map ......................................................... 4-3  Regional Geology Map (Detour Lake Property).................................................. 7-3  Second Derivative Aeromagnetic Data of the Detour Lake Property (OGS Geophysical Data Set 1062) ............................................................................... 7-4  Geology of the Detour Lake Mine and Block A Deposit...................................... 7-4  Geological Sections 19,360E (A-A’), 18,500E (B-B’) and 17,540E (C-C’) for Detour Lake and 16,340E (D-D’) for Block A ...................................................... 7-5  Fault Fill Quartz Veins ....................................................................................... 7-12  Free Gold in a Quartz Vein of the Main Zone ................................................... 7-13  Plan of All Drilling on the Property .................................................................... 10-2  Detour Lake Mine and Block A Drilling Program .............................................. 10-3  Percent of Expected Gold Results for Reference Materials of OREAS (Detour Gold) 2012 ......................................................................................... 11-12  Laboratory Pulp Duplicates Comparison Chart .............................................. 11-14  Preparation Duplicates Comparison Chart ..................................................... 11-15  Drill Core Duplicates Comparison Chart ......................................................... 11-16  Check Assay on Pulps Comparison Chart...................................................... 11-19  Correlation Charts for the 2012 Check Sampling Results (Detour Gold) ......... 12-9  Correlation Charts for the 2012 Check Sampling Results (Trade Winds) ..... 12-11  Box and Wihiskers Plots for the Confirmation Test Work ................................. 13-6  Gold in Tails (g/t) vs. P80 ................................................................................... 13-7  Oxygen versus Air – Gold Leaching Kinetic Comparison ................................. 13-8  Tail Au versus Head Grade to Gravity .............................................................. 13-9  Comparison of Actual Recovery Data to Predicted Recovery ........................ 13-12  Sampling Locations for Comminution Test Work............................................ 13-18  Comparison between Gravity Separation Performance for Detour Lake and Block A GV and ORT Samples ................................................................ 13-20  Comparison of Gravity Separation + Cyanidation Recovery Performance for Detour Lake and Block A ........................................................................... 13-20  Detour Lake Isometric View of the Open Pit Showing Mineralized Domains ... 14-4  Examples of Detour Lake GT Cumulative Frequency Plots of 2011 Data in Mineralized Domains ........................................................................................ 14-7  Examples of Detour Lake Histogram of 5 metre Composite Grades per Domain .............................................................................................................. 14-9  Examples of Detour Lake Correlograms of the Capped Grade of 5 metre Composites per Mineralized Domains ............................................................ 14-11  Detour Lake Bench 6,198 with Blocks in Mineralized Domains ..................... 14-13  Detour Lake Sections 17,000E and 19,300E with Blocks in Mineralized Domains .......................................................................................................... 14-14  Examples of Panels with Local Orientation of Search Ellipsoids.................... 14-17  Detour Lake 6,198 Bench with Composites and Estimated Block Grades ..... 14-18  Detour Lake Sections 17,500E and 18,000E with Composites and Estimated Block Grades ................................................................................. 14-19  Detour Lake Section 17,460E; Automatic and Final Classifications of Blocks.............................................................................................................. 14-21  Examples of Block A GT Cumulative Frequency Plots in Mineralized Domains .......................................................................................................... 14-27 

xiii

List of Figures

Figure 14-12  Figure 14-13  Figure 14-14  Figure 14-15  Figure 14-16  Figure 14-17  Figure 14-18  Figure 14-19  Figure 15-1  Figure 15-2  Figure 15-3  Figure 15-4  Figure 16-1  Figure 16-2  Figure 16-3  Figure 16-4  Figure 16-5  Figure 16-6  Figure 16-7  Figure 16-8  Figure 16-9  Figure 16-10  Figure 16-11  Figure 16-12  Figure 16-13  Figure 16-14  Figure 16-15  Figure 16-16  Figure 16-17  Figure 16-18  Figure 16-19  Figure 16-20  Figure 16-21  Figure 16-22  Figure 16-23  Figure 16-24  Figure 16-25  Figure 16-26  Figure 16-27  Figure 16-28  Figure 16-29  Figure 16-30  Figure 16-31  Figure 16-32  Figure 16-33  Figure 16-34  Figure 16-35  Figure 16-36  xiv

Examples of Block A Histograms of 5 metre Composite Grades per Domain ............................................................................................................ 14-29  Examples of Block A Correlograms of 5 metre Capped Grade Composites per Mineralized Domains ................................................................................ 14-31  Block A Bench 6,189 with Blocks in Mineralized Domains ............................. 14-32  Block A Section with Blocks in Mineralized Domains ..................................... 14-33  Block A Bench 6,189 with Composites and Estimated Block Grades ............ 14-36  Block A Sections with Composites and Estimated Block Grades................... 14-37  Block A Bench 6,189 with Automatic Resource Classification ....................... 14-38  Block A Sections 15,900 and 16,270 with Automatic Resource Classification ................................................................................................... 14-38  Plan View – Pit Optimization at $US1,000/oz ................................................... 15-5  Pit Slope Recommendations............................................................................. 15-6  Typical Ramp Profile and Dimensions .............................................................. 15-8  Ultimate Pit Design – Plan View ....................................................................... 15-8  Annual Material Movement Breakdown ............................................................ 16-2  Annual Head Grade and Gold Production Profile ............................................. 16-3  End of 2014-03 – Year 1 ................................................................................... 16-5  End of Period 2014-06 – Year 1 ....................................................................... 16-5  End of Period 2014-09 – Year 1 ....................................................................... 16-6  End-of-Period 2014-12 – Year 1 ....................................................................... 16-6  End-of-Period 2015-03 – Year 2 ....................................................................... 16-7  End-of-Period 2015-06 – Year 2 ....................................................................... 16-7  End-of-Period 2015-09 – Year 2 ....................................................................... 16-8  End-of-Period 2015-12 – Year 2 ....................................................................... 16-8  End-of-Period 2016 – Year 3 ............................................................................ 16-9  End-of-Period 2017 – Year 4 ............................................................................ 16-9  End-of-Period 2018 – Year 5 .......................................................................... 16-10  End-of-Period 2019 – Year 6 .......................................................................... 16-10  End-of-Period 2020 – Year 7 .......................................................................... 16-11  End-of-Period 2021 – Year 8 .......................................................................... 16-11  End-of-Period 2022 – Year 9 .......................................................................... 16-12  End-of-Period 2023 – Year 10 ........................................................................ 16-12  End-of-Period 2024 – Year 11 ........................................................................ 16-13  End-of-Period 2025 – Year 12 ........................................................................ 16-13  End-of-Period 2026 – Year 13 ........................................................................ 16-14  End-of-Period 2027 – Year 14 ........................................................................ 16-14  End-of-Period 2028 – Year 15 ........................................................................ 16-15  End-of-Period 2029 – Year 16 ........................................................................ 16-15  End-of-Period 2030 – Year 17 ........................................................................ 16-16  End of Period 2031 – Year 18......................................................................... 16-16  End of Period 2032 – Year 19......................................................................... 16-17  End of Period 2033 – Year 20......................................................................... 16-17  End of Period 2034 – Year 21......................................................................... 16-18  End of Period 2035 – Year 22......................................................................... 16-18  Mine Plan Section View 18,000E – Y2, Y7, Y12, Y17 .................................... 16-19  Mine Plan Section View 18,500E – Y2, Y7, Y12, Y17 .................................... 16-19  Mine Plan Section View 19,000E – Y2, Y7, Y12, Y17 .................................... 16-20  Mine Plan Section View 19,500E – Y2, Y7, Y12, Y17 .................................... 16-20  Mine Plan Section View 20,000E – Y5, Y10, Y15, Y20 .................................. 16-21  Final Pit and Pile Locations............................................................................. 16-23  4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Figure 16-37  Figure 17-1  Figure 17-2  Figure 17-3  Figure 17-4  Figure 17-5  Figure 17-6  Figure 17-7  Figure 17-8  Figure 20-1  Figure 21-1  Figure 21-2  Figure 24-1 

4 February 2014

Annual Truck Fleet Requirements .................................................................. 16-30  Operating Time and Rate of Milling for 2013 .................................................... 17-1  Monthly Average Throughput Rates for 2013 ................................................... 17-2  Simplified Process Flowsheet ........................................................................... 17-8  Process Plant General Layout ........................................................................ 17-10  Simple Layout of TMA Cells............................................................................ 17-11  TMA Downstream Construction ...................................................................... 17-14  TMA Centerline Construction .......................................................................... 17-14  Schedule for Water Management ................................................................... 17-17  General Site Plan .............................................................................................. 20-6  LOM Plan – Mining Rate and Unit Mining Cost ................................................ 21-5  LOM Processing Rate and Unit Costs – Process and G&A ............................ 21-6  2013 Reconciliation ........................................................................................... 24-3 

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Detour Lake Mine NI 43-101 Technical Report

List of Units and Abbreviations $ % ¢/kWh ° °C 3D AI Au BWI CWI D2 D3 D4 DDH DWI DWT DXF E FEL g ga g/cc g/g g/t GRG h Ha HP HQ ICP-OES kg kV kW kWh m. g/t m/h Ma mµ Mm3 MPa Mt 4 February 2014

unit currency percent sign cents per kilowatt hour degree degree Celsius three dimensions abrasion index gold bond ball mill work index crusher work index second generation of deformation third generation of deformation fourth generation of deformation diamond drill hole drop weight index drop weight test drawing interchange format east front end wheel loader grams billion years grams per cubic centimetres grams per gram grams per tonne Gravity recoverable gold hour hectare horsepower drill core size (6.4 cm diameter) Inductively coupled plasma-optical emission spectrometric kilogram kilovolt kilowatt kilowatt-hour metres x grams per tonne metres/hour million years microns million cubic metres megapascal million tonnes xvii

List of Units and Abbreviations

MW N Nb NPR NQ oz oz/t ppb ppm R RPD RQD RWI S SMC SMU tpa tpd tph tpoh tpy UTM W w/w X XRD Y Z

xviii

megawatt north number neutralization potential ratios drill core size (4.8 cm diameter) ounce ounce per tonne part per billion part per million Correlation coefficient Relative Percent Difference Rock Quality Designation bond rod mill work index south SAG mill comminution selection mining unit tonnes per annum tonnes per day tonnes per hour tonnes per operating hour tonnes per year Universal Transverse Mercator west weight/weight X coordinate (E-W) x-ray diffraction Y coordinate (N-S) Z coordinate (depth or elevation)

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

1.0 1.1

Executive Summary Introduction This Technical Report provides an updated mine production plan for the Detour Lake gold mine, located approximately 185 kilometers northeast of Cochrane, Ontario. The report is intended to comply with disclosure and reporting requirements set forth in National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”) of the Canadian Securities Administrators (including NI 43-101’s Companion Policy and Form 43-101F1). On February 4, 2014, Detour Gold Corporation (“Detour Gold”) announced an updated mineral resource and mineral reserve estimate for the Detour Lake Property (“Property”), which includes the Detour Lake mine and the Block A project. During 2013, Detour Gold and BBA Inc. (“BBA”) developed a mine production plan for the Detour Lake mine based on the mineral reserves released on February 4, 2014. This mine production plan, along with projected costs estimates, is the subject of this Technical Report. As part of this study, Detour Gold retained the following independent consulting firms: 

BBA Inc., under the direction of André Allaire, Eng., acting President and CEO, Patrice Live, Eng., Director, Mining; and



SGS Canada Inc., under the direction of Yann Camus, Eng., Project Engineer and Maxime Dupéré, P.Geo., Senior Geologist; and



AMEC Inc., under the direction of David Ritchie, M.Eng., P.Eng., Senior Associate Geotechnical Engineer and Geotechnical Engineering Group Manager.

This Technical Report draws heavily on 2013 operating experience, the work conducted for the feasibility study at the Detour Lake mine, which was detailed in a Technical Report dated June 30, 2010 (BBA, 2010); a further update on the mineral resources and reserves reported in a Technical Report dated March 15, 2011 (BBA, 2011); and an updated mine production plan for the Detour Lake mine in a Technical Report dated October 18, 2012 (BBA, 2012). Most of the authors of this report participated in the prior Technical Reports and have relied on some of the information contained in the feasibility study. Information relating to sample preparation, analyses and security; data verification; mineral processing and metallurgical testing; recovery methods; project infrastructure; and environmental studies have not changed significantly since reported in BBA (2012) and as such is essentially repeated in this report with minor updates. Production started on January 11, 2013 and the first gold pour occurred on February 18, 2013. On September 1, 2013, commercial production was declared, subsequent to having operated for a period of 60 consecutive days at an average of 41,428 tpd, approximately 75% of the design production capacity.

4 February 2014

1-1

Executive Summary

In this mineral resource and reserve update, Detour Gold used a gold price of US$1,000/oz for determining mineral reserves and US$1,200/oz for mineral resources. The effective date of this mineral resource and reserve update is December 31, 2013. All costs in this report are expressed in Canadian Dollars unless specifically stated otherwise. Totals may not add due to rounding. Refer to Cautionary Note at the end of this section.

1.2

Property Description and Location The Property is located mainly in northeastern Ontario, approximately 300 kilometres northeast of Timmins and 185 kilometres by road northeast of Cochrane. The Property is easily accessible all year long via Cochrane on provincial highway 652, followed by 34 kilometres of well-maintained gravel road. The Property is comprised of mining leases and claims totaling 627 km2, including the Sunday Lake Property, located immediately east of the Detour Lake mine, where Detour Gold has a 50% interest. The Property is 100% owned by Detour Gold (except for the Sunday Lake Property). The Detour Lake mine is located in the centre of the Property at the same site of the former Detour Lake mine, an open pit, and underground mining operation, which produced gold between 1983 and 1999.

1.3

Geology and Mineralization The Property is within the northwestern portion of the Abitibi Greenstone Belt (“AGB”) in the Superior Province of the Canadian Shield craton. Supracrustal rocks within the Detour Lake area are comprised of a thick sequence of mafic to ultramafic volcanic rocks, referred to as the Deloro Assemblage (“DA”), in structural contact to the south with the younger sediments of Caopatina Assemblage (“CA”). This contact between the DA and CA is characterized by a regional scale thrust zone referred to as the Sunday Lake Deformation Zone ("SLDZ"). The structures of the SLDZ are spatially related to most of the gold mineralization observed in the Detour Lake area. The gold mineralization in the Detour Lake area is believed to be relatively late and emplaced after tectonic juxtaposition of the DA and CA and is not synvolcanic as it was interpreted by Marmont and Corfu (1989). Gold mineralization within the Detour Lake deposit is principally observed north of the SLDZ (hangingwall) along an east-west strike length of over 8 kilometres within a corridor several 100s metres wide. It forms a stockwork of auriferous quartz veins that splay from a flexure that coincides with the northern limb of a shallow west plunging antiform. There are two types of gold mineralization recognized in the Detour Lake area:

1-2



A wide and generally auriferous sulphide-poor quartz vein stockwork formed in the hangingwall of the SLDZ; and



A gold mineralization overprinting the early auriferous stockwork, principally in the hangingwall of the SLDZ, with a higher sulphide content. 4 February 2014

Detour Lake Mine NI 43-101 Technical Report

The gold mineralization occurs in different rock types within broad sub-vertical mineralized envelopes and splits into several domains sub-parallel to the orientation of the SLDZ. It is principally contained in discrete fault-fill or shear hosted, extensional quartz vein networks, and broad lithology controlled mineralized zones with a weaker vein association. The gold mineralization styles in Block A are near identical to the Detour Lake mine. Gold mineralization is within a relatively weak quartz vein stockwork with a low sulphide content (mainly pyrite and pyrrhotite).

1.4

Exploration and Drilling Activities Detour Gold drilled over 1,500 core holes in the process of delineating both Detour Lake and Block A deposits. To date, Detour Gold has drilled over 48,000 metres in other areas of the Property. Surface exploration activities also included geochemical and geophysical surveys, geological mapping, and sampling.

1.5

Drilling, Quality Control, and Data Verification The database used for the reserve and resource estimation is a sub-set of all holes drilled on the Property. This database includes 1,395 drill holes by Detour Gold totaling 584,798 metres to outline the Detour Lake deposit. Detour Gold also completed 44,626 metres of drilling in 132 drill holes on the Block A deposit. Both deposits have been tested on 40 by 40 metre drill spacing. A small area between both pits still remains to be in-filled. SGS Canada Inc. (“SGS Geostat”) validated the core sampling procedures used by Detour Gold as part of an independent verification program. SGS Geostat concluded that the drill core handling, logging, and sampling protocols used by Detour Gold for Detour Lake and Block A meet conventional industry standards and conform to generallyaccepted best practices. It is SGS Geostat’s opinion that Detour Gold is operating according to an industry standard QA/QC program for the insertion of control samples into the stream of samples. SGS Geostat completed independent analytical check programs on selected drill holes from the 2010, 2011, and 2012 drilling programs. Results of the duplicate samples generally show a good to moderate correlation with the original assays, although a bias was seen for the Trade Winds Ventures Inc. (“Trade Winds”) drilling on the Block A project. Further testing showed that the impact on Block A resource estimate was minimal and did not cause a material impact, although further investigation is recommended. The results of all check sampling programs outline the significant variability of the high gold values due to the nugget effect observed at Detour Lake and Block A and highlight the necessity of capping the high gold values for the mineral resource estimation process.

1.6

Mineral Processing and Metallurgical Testing The metallurgical test work completed to support this Technical Report was drawn from the feasibility study for the Detour Lake deposit and was reviewed by BBA. In subsequent phases of metallurgical evaluation, additional test work required to support optimization of

4 February 2014

1-3

Executive Summary

the plant design criteria and for Block A development was conducted by BBA. The key points are as follows: Sample Preparation The sample selection approach provided a sufficiently large number of metallurgical test composites of varying gold grade, rock type and mineralization that were selected from core data. Comminution Tests For the Detour Lake mine, comminution test work was conducted in 2007 and 2009 (BBA, 2012). Test work includes the determination of the specific gravity (SG), the overall hardness (using SMC Test® A x b), the crushing work index (CWI), the bond rod mill work index (RWI), the bond ball mill work index (BWI) and the abrasion index (AI). Comparison of the grindability results (Axb, RWI and BWI) showed that the Detour Lake mineralization can be considered as being in the hard to very hard range, and is generally consistent among the main rock types containing the gold mineralization. For Block A, a total of 17 HQ drill core holes were drilled in early 2012 for the purpose of metallurgical testing. The results of comminution tests carried out on the selected samples show that when comparing comminution characteristics of Block A with those of Detour Lake mine, it can be seen that although the two are categorized as hard in terms of both DWT resistance to impact (Axb value) and abrasion breakage (ta value), the mineralized material from Block A is slightly softer (in terms of RWi and BWi) and less abrasive (Ai) than the Detour Lake mine ore. In general, the grinding and crushing characteristics of the samples from the Block A are similar to those of the samples from Detour Lake mine. Grinding Circuit Simulations The grindability results from the comminution testing were used to conduct simulations of different circuit configurations and operational variables. Based on the results of these tests, the selected grinding circuit configuration for the Detour Lake mine was a semi-autogenous (“SAG”) and ball mill with closed circuit crushing (SABC) coupled with secondary crushing to optimize throughput by reducing the feed size to the SAG mill. A gyratory crusher is used for primary duty. The results of the simulations showed that the design basis was appropriate for a final grind size P80 of 95 µm with 55,000 tpd as a base case; but also illustrated the possibility of increasing throughput from 55,000 tpd to 61,000 tpd by allowing for a coarser final grind (P80) from 95 µm to 105 µm. Gravity Recoverable Gold Gravity gold recovery testing was performed for the overall rock type composites that represent 99.3% of the Detour Lake deposit. The average free gold recovery using 1-4

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

variable grades with several different gravity testing methods consistently returned recovery values in the 35% to 45% range. For the Block A composites, the test work results indicated that the recovery profiles from gravity separation testing are similar to the Detour Lake feasibility study test work results. Grind Size to Recovery Relationship Optimization test work included determining the relationships between grinding size, leach time and gold recovery, and developed and improved understanding for the impact to leach kinetics with reagent consumption. Results of this testing determined that the gold recovery is minimally influenced by a finer grind size when the P80 is less than 110 µm. In the range from 70 to 105 µm, the loss in overall gold recovery is approximately 0.5% per 10 µm of coarser grinding. Optimization of Leach Time and Leach Conditions Testing supports a range of leaching time from 20 to 48 hours. The results showed that the gold in residue (tail) per leach time reached a plateau after approximately 25 hours. Conclusions that were drawn from the additional optimization are: 

The lowest gold in residue (higher gold recovery) is found around 28 and 32 hours; and



The optimal leaching time selected was 29 hours for a grind of P80 95 µm.

For the Block A composites, the leaching behavior of the gravity was found to be almost identical to that of the Detour Lake mine samples. Copper Mineralization The Detour Lake mine contains small concentrations of copper (“Cu”) averaging approximately 0.04% from all metallurgical data. Testing showed that if the operating conditions are maintained to keep the pH between 10.5 and 11.0, and the free cyanide concentration at a ratio of 4.5 moles of cyanide (“CN”) per mole of copper, the gold will continue to load onto carbon and displace Cu, thereby maintaining effective operation conditions. Recovery Model Review of the process plant data from October to December 2013 indicated that the gold recovery was 1 to 3% higher than predicted by the pre-feasibility and feasibilities studies model. Based on this data, a 1% gold recovery increase was added to the gold recovery model for the life of mine (“LOM”) plan. Cyanide Detoxification Laboratory test work was conducted from the remains of the leaching tests to investigate the detoxification of cyanide slurries (cyanide destruction). For this test work, the SO2/air 4 February 2014

1-5

Executive Summary

method was the selected process since this is an industry standard that is easily benchmarked with other operations.

1.7

Mineral Resources SGS Geostat conducted a mineral resource estimate (“MRE”) of the Detour Lake mine and Block A gold deposits using the data from both the historic drilling and Detour Gold’s drilling from 2007 to 2012. A database was provided by Detour Gold and separated into two sub-sets to facilitate the estimation process. The database contains 7,107 core holes totaling 1,411,881 metres with collar, survey, geological and assay information. In the process of completing the resource estimate update, SGS Geostat validated and verified the database, interpretation and available data. The block size dimensions chosen for the Detour Lake model are 10 x 5 x 12 metres, while block size dimensions for the Block A model are 10 x 5 x 6 metres. Block size dimensions were based on the existing drilling pattern, spatial distribution and mine planning consideration. The resource estimates were interpolated by nearest neighbour, inverse distance cubed and ordinary kriging (“OK”) methodologies. No significant discrepancies exist between the methods, and values obtained from OK have been used for the resource tabulation. The OK block models were exported to the MineSight software for pit optimization, based on Lerchs-Grossman 3D algorithm. Optimized pit shells were generated by BBA on Measured and Indicated resources only. Gold price used for the resource optimization was US$1,200/oz. Various other economic parameters such as mining and milling costs, minimum profit payment, geotechnical parameters as well as milling recovery were used in the definition of the optimized pit shells. Mineralized material must be contained within those pit shells to classify as mineral resources. Mineral resources are stated exclusive of mineral reserves. Cut-off grades (“CoG”) of 0.5 and 0.6 g/t Au were used for Detour Lake mine and Block A, respectively. Mineral resources do not include additional mining dilution. Combined in-pit resources for the Detour Lake mine and Block A deposits are presented Table 1-1.

1-6

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Table 1-1

Summary Mineral Resource1, 2, 3, 4, 5 Effective December 31, 2013 Contained Gold Ounces (000's)

Tonnes (millions)

Grade (g/t Au)

17.9

1.36

782

Indicated (I)

118.4

1.07

4,084

Total (M&I)

136.3

1.11

4,866

21.7

0.81

564

Category Measured (M)

Inferred 1

CIM definitions were followed for mineral resources. 2 The cut-off grades used are 0.5 g/t Au for Detour Lake mine and 0.6 g/t Au for Block A. 3 Mineral resources were calculated using a gold price of US$1,200/oz. 4 Mineral resources are exclusive of mineral reserves. Mineral resources that are not mineral reserves do not have demonstrated economic viability. 5 Capping grades estimated by domains and vary from 15 m. g/t to 75 m. g/t Au.

1.8

Mineral Reserves For the mineral reserve estimation, the resource block model was provided by SGS Geostat and was transferred into the MineSight software and an economic model was prepared for the pit optimization. The pit optimization uses the Lerchs-Grossman 3D (LG 3D) algorithm in MineSight. The general overall pit slopes used in the pit optimization were 50° in the hangingwall (north wall) and 48° for the footwall (south wall), although actual slope angles vary according to pit slope design work done by Golder (BBA, 2010). The mineral reserves were estimated through an open pit optimization exercise using the Measured and Indicated category resources in the block model, followed by a detailed engineered design to include all aspects of a final pit (main haul road, geotechnical berms, etc.). The mineral reserves inside the engineered pit design were estimated using a CoG 0.5 g/t Au, based on a gold price of US$1,000/oz. The Proven and Probable reserves, including 2.4 Mt of ore at a grade of 0.82 g/t Au on stockpiles as of December 31, 2013 amount to 476.4 Mt at 1.02 g/t Au, or 15.5 million ounces of gold contained. Total waste, including Inferred resources, backfilled stopes, overburden and waste rock is 1.68 billion tonnes, resulting in a waste to ore ratio of 3.54 to 1. No additional dilution was added for the pit shell optimization since an inherent grade dilution of 11.7% is included in the OK block model. The mineral reserve estimate inside the detailed engineered pit design includes an additional mining dilution estimated at 4.0% at a grade of 0.20 g/t Au, resulting in a global dilution of 15.7%. The mining loss is estimated at 5%. The mineral reserves for the Detour Lake mine are presented in Table 1-2.

4 February 2014

1-7

Executive Summary

Table 1-2

Detour Lake Mine Mineral Reserves1, 2, 3, 4, 5 Effective December 31, 2013 Contained Gold Ounces (000's)

Tonnes (millions)

Grade (g/t Au)

94.4

1.29

3,901

Probable

379.7

0.95

11,585

Proven + Probable

474.0

1.02

15,486

2.4

0.82

63

476.4

1.02

15,549

Category Proven

Stockpiles Total 1

CIM definitions were followed for mineral reserves. 2 Mineral reserves are estimated using a gold price of US$1,000/oz. 3 Mineral reserves are based on a cut-off grade of 0.5 g/t Au. 4 Reserves include ore loss of 5% and dilution of 4% at 0.2 g/t Au (7% at 0.2 g/t for 2014). 5 Totals may not add due to rounding.

1.9

Mining Methods The updated mine production plan for the LOM is based on the year-end 2013 mineral reserves estimates. The mining schedule used a CoG of 0.5 g/t throughout the LOM. Material above this CoG will be used as process plant feed. Material with a grade greater than 0.4 g/t but less than 0.5 g/t will be stockpiled for possible future processing. No revenue arising from the processing of this mineralized material has been included in the economic analysis. The mine development sequencing is based on the September 2013 updated block model and operating experience gained since start-up. The remaining LOM is estimated at 21.7 years, based on a processing rate of 19.0 Mt for 2014, 20.1 Mt for 2015, 21.3 Mt for 2016 and 22.3 Mt per annum after reaching full mill throughput capacity in early 2017. Total remaining LOM gold production is estimated to be 14.3 million ounces, averaging approximately 660,000 ounces per year. The mining method uses a conventional open pit truck and shovel operation. The estimated mine mobile fleet requirements include a maximum of 41 ultra-class haul trucks, two electric cable shovels, three hydraulic shovels for production and two for support. Seven large track-mounted blast-hole drills are required for production drilling together with three smaller drills for support. A fleet of support equipment, including track and rubber-tire dozers, motor graders, auxiliary excavators, as well as other miscellaneous maintenance support equipment is also included.

1.10 Recovery Methods The process plant design was based on the feasibility study and is described in prior reports (BBA, 2010, 2011, 2012). Construction was largely completed by December 2012. Commissioning of line 1 started in December 2012 and line 2 in April 2013. Production started on January 12, 2013 and first gold pour occurred February 18, 2013. Commercial production was reached in August 2013 after having operated for a period of 60 consecutive days at an average of 41,428 tpd, corresponding to approximately 75% of the design production. 1-8

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

A total of 11.2 Mt were processed in 2013. By the fourth quarter 2013, the process plant had operated at 2,335 tpoh with an average daily production of 37,090 tpd and an overall recovery of 92.1%. In 2014, the plant is forecasted to process 19.0 Mt at an average rate of 52,000 tpd with an average recovery of 92% and an average availability of 86.6%. Starting in 2014, a debottlenecking and operation stabilization exercise will be initiated to increase the production throughput to 61,000 tpd in 2017 and beyond. It is estimated that the plant capacity will reach 22.3 Mt/year in 2017 and will remain at that level for the balance of the LOM. Tailings Management Area The tailings management area (“TMA”) for the feasibility study was initially designed for a total storage capacity of approximately 260 Mm3 (363 Mt) with potential for additional raises and/or expansion to accommodate additional capacity as required. During 2013, an evaluation of TMA expansion alternatives determined that approximately 204 Mm3 (287 Mt) of incremental tailings produced from the increased (updated) reserves and resources can be accommodated in the TMA with minor changes to the footprint, height and final closure concepts as outlined in the feasibility study. Accordingly, the total tailings capacity within the current design framework is 464 Mm3 (650 Mt). This exceeds the tonnage of Proven and Probable reserves on which this LOM plan is based. Estimates for the additional sustaining capital costs to accommodate reserve tonnage have been included as part of the financial analysis. Also during 2013, Detour Gold obtained approval from the MNDM to construct the tailings dams using a ‘centerline’ method rather than the originally proposed ‘downstream’ method.

1.11 Project Infrastructure The site infrastructure required for the Detour Lake mine has already been constructed. Site access is provided through a guard/security house located at the entrance to the site on the main access road. At the Detour Lake mine site, workers are accommodated in two camps: 1) The ‘Permanent Camp’, located six kilometres west of the Detour Lake mine, capacity of 509 persons, and 2) The ‘Construction Camp’, near Sagimeo Lake with a current capacity of 365 persons. The mine site was connected to a 230 kV power line in July 2012. The 230 kV transmission line provides more than the 85 MW of power consumption needed to service the entire Detour Lake mine operation. The process plant is comprised of three main buildings: the primary crushing building, the secondary and pebble crushing building and the main process plant building. The process plant building consists of the requisite facilities to process 55,000 tpd to 61,000 tpd of ore. Inside the main building are two SAG mills, two ball mills, a gravity circuit, a CIP circuit, a gold room, pumps and piping, electrical systems, control systems and 4 February 2014

1-9

Executive Summary

process support systems. Additional process facilities are located adjacent to these buildings. Adjacent to the primary crusher, a run of mine (“ROM”) stockpile was established to help manage the crusher downtime. The mine production plan over the LOM estimates the mining of 1,192 Mt of non-acid generating (“NAG”) waste rock, which will be stored in waste dumps. The quantity of potentially acid generating (“PAG”) waste rock in the LOM is estimated at 298 Mt. This material will be stored to the north of the Detour Lake open pit. Mineralized material with a grade of 0.4-0.5 g/t Au will be stockpiled (approximately 108 Mt at a grade of 0.45 g/t Au). In the current LOM mine plan, this mineralized material is not included in the planned process plant feed. An overburden stockpile with a capacity of approximately 80 Mt will be required to accommodate the overburden at Detour Lake. Orica Ltd. has constructed a bulk explosives plant approximately 3.5 kilometres west of the process plant facilities. The nominal capacity of this plant is approximately 30,000 tonnes of explosives per year, which is sufficient to meet the mine’s requirements. The Detour Lake mine site facilities already include sufficient heavy equipment workshops for the first three years of the mining operations. The Mine Service Facility is located approximately 1.2 kilometres south of the processing plant. An appropriately sized truck wash facility has also been constructed. Site administration facilities have been constructed adjacent to the mine service facility. Sufficient roads have been built to provide general access to all main areas of the mine and processing plant facilities. Additional roads were constructed over 2013. Facilities in Cochrane to support the Detour Lake mine include warehouses, administration offices, and a bus terminal. Infrastructure in Cochrane also includes an assay laboratory, owned and operated by SGS Canada Inc. (“SGS Minerals”), under a contract with Detour Gold. This laboratory is now in operation and can process about 200,000 samples per year. It operates in accordance with SGS Minerals’ standardized analytical methods and industry standard QC protocols.

1.12 Environmental and Aboriginal Matters Environmental aspects have figured prominently in the development of the site layout and feasibility study designs for the Detour Lake mine. Environmental considerations were critical to the selection of the preferred alternative for several key project components, including the proposed TMA and other mineral waste storage locations. The Federal and Provincial approvals that were required for the construction and operation of the Detour Lake mine have been obtained. The permits required to date to operate and work have been received and others will be obtained as the Detour Lake mine evolves. There are no outstanding approvals to impede the continuation of the operations. 1-10

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Detour Lake Mine NI 43-101 Technical Report

Geology and Geochemistry A comprehensive assessment for metal leaching and acid rock drainage (MLARD) was conducted during mine design and showed a small portion of the waste rock had the potential for some reactivity. Consequently, a conservative approach was adopted in the mine operations by including a drilling and sampling program of all waste rock to identify such material and to allow separate storage in designated waste rock stockpiles. This program has been successfully implemented with the operating data base showing that the quantity of PAG rock is lower than the original predictions. Monitoring of four small waste rock piles from the previous operations, which contain much higher levels of sulfide minerals, has shown virtually no problems from MLARD after 17 years of operation and 10 years of post-closure. Ongoing research is in progress to obtain more information from these piles for future application to the mine operating and closure plans. A similar assessment of the tailing materials showed a very low risk of MLARD and no special management plans were deemed to be necessary. The operational testing of tailings over the early operations has verified this prediction. Surface Water Comprehensive surface and groundwater monitoring programs have been implemented related to the operating permits. A dynamic water balance has been developed to manage all water around the site and to achieve no discharges from the tailing pond system. Strategies to manage the mine water independently have been developed over the LOM which includes the ability, if necessary, to seasonally discharge treated effluent to the local water systems in compliance with the rigorous provincial operating permits. To date, extensive recycle has been achieved and such discharges have not been needed. The expansion of the open pit to the west will likely have an impact on Walter Lake, a small shallow lake that drains to the south. In advance of this area being developed, the relevant regulatory processes required will be followed to allow this modification to the mine plan. This size increase of the pit area is minor compared to the prior pit area and hence the closure strategy for the development of a pit lake for this area remains unchanged. This development is not expected to change the financial assurance costs for closure. Social and Community Impact Socio-economic impacts associated with local communities have been and continue to be overwhelmingly positive. The local communities have expressed strong support for the Detour Lake mine, and particularly by the Town of Cochrane representatives. Overall effects are considered significant and positive. As Detour Lake has moved to operations, the third phase of the consultation program with local communities is one of providing employment, training, and business opportunities 4 February 2014

1-11

Executive Summary

information. Since the start of construction, Detour Gold has been committed to providing updates on environmental compliance. The Company has entered into formal agreements to facilitate the ongoing consultation and engagement of the Aboriginal communities. To formalize the Detour Gold-Aboriginal community relationship, Impact Benefits Agreements or similar agreements were finalized with four groups and ratified by the respective communities. These agreements indicate a plan to ensure the impacted Aboriginal groups are involved in the environmental assessment process and are involved in creating training plans and promoting local employment and business opportunities and financial compensation. Mine Closure The estimated costs of mine closure and ongoing monitoring are $69.6 million. This cost was accounted for in the cash flow at the end of the LOM. As of the date of this report, Detour Gold has submitted $33.4 million in financial assurance to the MNDM.

1.13 Capital and Operating Costs Sustaining Costs A complete review of the sustaining capital required for the LOM has been completed with the experience gained from the first year of operation. Table 1-3 provides a summary of these expenditures for the LOM. Table 1-3

Summary of Sustaining Capital Cost Estimate

Description

Sustaining Capital LOM ($ Million)

Mining

535

Process Plant

126

Tailings Management

454

G&A

28

Total

1,143

Mine Closure

70

5 years 2014 to 2018 ($ Million) 168

5 years 2019 to 2023 ($ Million)

5 years 2024 to 2028 ($ Million)

7 years 2029 to 2035 ($ Million)

69

255

43

71

24

20

11

203

114

70

67

14

8

5

1

456

215

350

122 70

Sustaining capital for the Detour Lake mine is summarized for the LOM and for indicative 5 year periods (with the exception of the last period at 7 years). Sustaining capital cost estimates are driven by mining fleet expansions during 2014 to 2018 and mining equipment replacements over 2024 to 2029. TMA costs fall off during the period 2024 to 2035 because the base of all three cells will have been completed. Deferred Stripping From an accounting perspective, stripping costs which provide probable future economic benefits, provide identifiable improved access to the ore body and which can be measured 1-12

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Detour Lake Mine NI 43-101 Technical Report

reliably are capitalized. Detour Gold has applied deferred stripping in the financial model and it resulted in the capitalization of $614 million of mining operating costs over the LOM. Operating Costs The operating cost estimate of the Detour Lake operation covers mining, ore processing, tailings and water management, general and administration (G&A) as well as infrastructure and services. Over the LOM, operating costs were estimated from a combination of experience gained in 2013 and first principles. Mining costs were estimated from equipment fleet requirements and the associated labour, fuel and other consumables, which arose from physicals. Processing costs were estimated from throughput, ore characteristics, energy, labour and consumables costs. G&A were estimated from the current camp requirements and the Cochrane office based costs. Total cash costs per ounce of gold sold1 are projected to average $723 over the LOM (Table 1-4). Table 1-4

LOM Total Cash Costs

Mining Costs

$/t milled

$/t mined

$/oz Sold1

11.55

2.56

392

Processing Costs

7.82

266

General and Administration

2.44

83

21.81

741

Sub-Total 2

Other Adjustments

(18)

Total Cash Costs (LOM)

723

1.14 Economic Analysis The Detour Lake mine LOM economics estimate is based on the 2013 year-end mineral reserves. Assumptions For the gold price assumptions, Detour Gold and BBA reviewed a consensus survey undertaken by a leading Canadian financial firm, which compiled commodity prices forecast from approximately 25 financial institutions. This survey dated December 31, 2013 was used to establish a base case gold price assumption of US$ 1,200/oz for all years. For the silver price assumptions, the same survey was used to set a base case silver price assumption of $20/oz for all years.

1

Refer to the section on Non-IFRS Financial Performance Measures at the end of section 1.

2

Other adjustments include costs for deferred stripping, agreements with Aboriginal communities, refining charges and are net of silver by-product credits. 4 February 2014

1-13

Executive Summary

The exchange rates of US$ to Cdn$ (based on average consensus rates) below are used as a parameter: 2014

1.05

2015

1.07

2016

1.08

2017 and beyond

1.10

Taxation Over the LOM, Federal and Provincial income taxes have been estimated at $1,038 million. Over the LOM, Ontario mining taxes have been estimated at $375 million. Discount Rate Over the past 10 years, real risk-free interest rates have ranged from near zero to around 5%. In view of this and other factors, it was decided to apply discount rates of 5%, 7.5%, and 10% in the Base Case. At the Base Case discount rate, NPV 5% is $3.42 billion and $2.79 billion before and after tax, respectively. LOM total cash costs1 are $723/oz sold and total cash costs including capital expenditures1 (and deferred stripping) are $848/oz sold. Sensitivity Analysis Taking the Base Case described above as a starting point, the sensitivity of the Detour Lake mine pre-tax NPV 5% to changes in gold price, exchange rate, capital and operating costs was tested. Table 1-5 represents the results of this analysis. It can be seen that, as is typical for most mining projects, the drivers of revenue have the greatest impact on project returns. The economics of the Detour Lake mine are almost as sensitive to changes in the exchange rate, since these directly affect Canadian Dollar receipts but have little impact on estimated operating costs or on the Canadian Dollar denominated portion of the capital cost. The Detour Lake mine is shown to be only moderately sensitive to overall operating costs, and has little sensitivity to capital cost changes within the range tested.

1

1-14

Refer to the section on Non-IFRS Financial Performance Measures at the end of section 1.

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Detour Lake Mine NI 43-101 Technical Report

Table 1-5

Sensitivity Analysis

Discount Rate

0%

5%

7.5%

10%

Pre-tax NPV Cdn$ billions @ US$1,000

3.42

1.64

1.18

0.87

Pre-tax NPV Cdn$ billions @ US$1,100

4.96

2.53

1.89

1.44

Pre-tax NPV Cdn$ billions @ US$1,200

6.50

3.42

2.60

2.02

Pre-tax NPV Cdn$ billions @ US$1,300

8.04

4.32

3.31

2.60

Pre-tax NPV Cdn$ billions @ US$1,400

9.58

5.21

4.02

3.18

-10%

Base case

3.50

3.42

-10%

Base case

4.05

3.42

2.80

1.05

Base case

+1.15

2.99

3.42

3.97

Gold price (US$/oz)

Capital Costs Pre-tax NPV 5% (Cdn$ billions)

Operating Costs Pre-tax NPV 5% (Cdn$ billions)

Foreign Exchange Pre-tax NPV 5% (Cdn$ billions)

+10% 3.35

+10%

1.15 Interpretations and Conclusions The mineral resources and mineral reserves were updated using current economic information and production results. The mineral resources include Detour Lake and the adjacent Block A project. A new LOM plan was prepared for the Detour Lake operation. SGS Geostat completed the mineral resource updates for the year-end 2013, for both the Detour Lake mine and Block A project. They concluded that the drill core handling, logging and sampling protocols used by Detour Gold for Detour Lake and Block A are at conventional industry standard and conform to generally-accepted best practices; and confirmed that the system is appropriate for the collection of data suitable for NI 43-101 compliant mineral resource estimates. SGS Geostat found that the assumptions, parameters, and interpretation are reasonable and appropriate to support the current MREs. The Detour Lake gold mine has been in operation for nearly one year with commercial production declared in September 2013. The operational results have shown that metallurgical test work and process plant design completed for the feasibility study were adequate. The updated LOM plan based on the 2013 year-end reserves has been carried out according to industry standards and uses cost estimates that are appropriate based on operational experience acquired during 2013, Detour Gold and BBA’s knowledge, judgment and experience. Based on actual process plant performance data from October to December 2013, gold recovery was 1 to 3% higher than the prior recovery assumption (pre-feasibility and feasibility studies model). Following this information, a 1% gold recovery increase was added to the gold recovery model for the LOM plan.

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1-15

Executive Summary

This LOM plan is based on updated 3D pit optimization, followed by a redesign of the Detour Lake mine pit (with haulage access and bench configuration) followed by scheduling the ore and waste as identified within the pit design. BBA performed this work together with input from Detour Gold. Appropriate costs and equipment productivity rates were applied to the mine schedule. This work served as the basis to derive operational expenditure estimates. Sustaining capital expenditures were estimated based on mine equipment fleet, process plant and tailings facility requirements. It is BBA’s opinion that the majority of the potential risks associated with a mining operation were addressed in the updated LOM plan.

1.16 Recommendations The Detour Lake mine declared commercial production on September 1, 2013. In continuation with the work completed to date, the following aspects of the mine operation should be examined in more detail to further optimize the economics of Detour Lake (refer to section 26.0 for further details): 

Continuation of the grade control process including investigating and implementing methods and technology to improve grade control and mining selectivity; and validation for short-range planning (3 to 6 months);



Evaluation of smaller benches (i.e. 7.5 metres) in central areas of the pit that would be mined with smaller equipment and could result in improved dilution control; and evaluation of larger benches (i.e. 15 metres) in waste which could offer increased productivity and result in lower costs with minimal impact on dilution;



Evaluation and implementation of emerging technology to reduce variability in ore feed;



Continue to segregate (stockpile) ‘mineralized waste’ which could potentially be processed during or after the LOM depending on the gold price environment;



Investigation of potential improvement for pit slopes; and



Gold recovery could potentially be increased as actual results have shown higher gold recovery than projections. Further improvement could be expected with maximum utilization of the gravity circuit.

Further work is recommended for the Block A project:

1-16



Advancing the Block A project to pre-feasibility level and evaluate best approach to incorporate into Detour Lake mine plan;



Further monitoring is recommended to investigate a potential bias on Trade Winds assay results (higher gold values) on the Block A project. The validation work on the estimation of mineral resources did show a minimal impact overall but it may be more significant locally. Detour Gold is in the process of sending additional samples and pulps for additional testing; and

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Detour Lake Mine NI 43-101 Technical Report



Further delineation work in the area between Detour Lake mine and Block A to allow for better modeling and estimation of potential mineralization adjacent to the mine.

In addition, exploration programs in the Lower Detour area should continue to follow up on the high-grade intercepts encountered in several structural zones.

Cautionary Notes Forward-Looking Information This Technical Report contains certain forward-looking information and statements as defined in applicable securities law (referred to herein as “forward-looking statements”). Forward-looking statements include, but are not limited to, statements with respect to the updated mine plan and economic analysis of the Detour Lake mine including, but not limited to, the life of mine plan, the waste to ore ratio, processing and production rates, grades, metallurgical recovery rates, operating and sustaining capital costs, the projected life of mine, the net present value, opportunities to optimize the mine operation, the success and continuation of exploration activities, the future price of gold, reclamation obligations, government regulations and environmental risks. Forward-looking statements involve known and unknown risks, uncertainties and other factors which may cause actual results, performance or achievements to be materially different from any of its future results, performance or achievements expressed or implied by forward-looking statements. These risks, uncertainties and other factors include, but are not limited to, assumptions and parameters underlying the life of mine update not being realized, a decrease in the future gold price, discrepancies between actual and estimated production, changes in costs (including labour, supplies, fuel and equipment), changes to tax rates; environmental compliance and changes in environmental legislation and regulation, exchange rate fluctuations, general economic conditions and other risks involved in the gold exploration and development industry, as well as those risk factors discussed in the Technical Report. Such forward-looking statements are also based on a number of assumptions which may prove to be incorrect, including, but not limited to, assumptions about the following: the availability of financing for exploration and development activities; operating and sustaining capital costs; the Company’s ability to attract and retain skilled staff; sensitivity to metal prices and other sensitivities; the supply and demand for, and the level and volatility of the price of, gold; the supply and availability of consumables and services; the exchange rates of the Canadian dollar to the U.S. dollar; energy and fuel costs; the accuracy of reserve and resource estimates and the assumptions on which the reserve and resource estimates are based; market competition; ongoing relations with employees and impacted communities and general business and economic conditions. Accordingly, readers should not place undue reliance on forward-looking statements. The forwardlooking statements contained herein are made as of the date hereof, or such other date or dates specified in such statements.

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1-17

Executive Summary

All forward-looking statements in this Technical Report are necessarily based on opinions and estimates made as of the date such statements are made and are subject to important risk factors and uncertainties, many of which cannot be controlled or predicted. Detour Gold and the Qualified Persons who authored this report undertake no obligation to update publicly or otherwise revise any forward-looking statements contained herein whether as a result of new information or future events or otherwise, except as may be required by law. Information Containing Estimates of Mineral Reserves and Resources The mineral reserve and resource estimates reported in this report were prepared in accordance with Canadian National Instrument 43-101Standards of Disclosure for Mineral Projects (“NI 43-101”), as required by Canadian securities regulatory authorities. For United States reporting purposes, the United States Securities and Exchange Commission (“SEC”) applies different standards in order to classify mineralization as a reserve. In particular, while the terms “measured,” “indicated” and “inferred” mineral resources are required pursuant to NI 43-101, the SEC does not recognize such terms. Canadian standards differ significantly from the requirements of the SEC. Investors are cautioned not to assume that any part or all of the mineral deposits in these categories constitute or will ever be converted into reserves. In addition, “inferred” mineral resources have a great amount of uncertainty as to their existence and great uncertainty as to their economic and legal feasibility. It cannot be assumed that all or any part of an inferred mineral resource will ever be upgraded to a higher category. Under Canadian securities laws, issuers must not make any disclosure of results of an economic analysis that includes inferred mineral resources, except in rare cases.

Non-IFRS Financial Performance Measures The Company has included “Total cash cost per gold ounce sold (TCC)” and “Total cash cost plus total capital per gold ounce sold (TCC plus Total Capital)” in this document which is a non-IFRS measure. The Company believes that these measures, in addition to conventional measures prepared in accordance with IFRS, provide investors an improved ability to evaluate the underlying performance of the Company and its ability to generate operating earnings and cash flow from its mining operations. Total cash costs per gold ounce sold include production costs such as mining, processing, refining, site administration, costs associated with providing royalty in-kind ounces, and costs for agreements with Aboriginal communities, but are exclusive of depreciation and depletion, reclamation, non-cash share-based compensation and deferred stripping. Total cash costs are reduced by silver sales and divided by gold ounces sold to arrive at total cash costs per gold ounce sold. Total cash costs plus total capital per gold ounce sold includes TCC as calculated above plus sustaining capital and deferred stripping divided by gold ounces sold. These non-IFRS measures are intended to provide additional information and should not be considered in isolation or as a substitute for measures of performance prepared in accordance with IFRS. These measures do not have any standardized meaning 1-18

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Detour Lake Mine NI 43-101 Technical Report

prescribed under IFRS, and therefore may not be comparable to other issuers. Other companies may calculate this measure differently.

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1-19

Detour Lake Mine NI 43-101 Technical Report

2.0 2.1

Introduction Purpose and Terms of Reference The purpose of this Technical Report is to provide an update to the October 18, 2012 Technical Report in light of subsequent development, including the start of gold production, a revised mineral resource and reserve estimate, and design adjustment in the tailings management facility for the Detour Lake mine located in Ontario, Canada. This Technical Report also updates the mine production plan and operating costs following nearly a year of gold production at the Detour Lake mine. The Technical Report draws on the work conducted for the feasibility study, which was detailed in BBA (2010). Most of the authors of this report participated in the prior Technical Reports (BBA 2011, 2012) and have relied on some of the information contained in the feasibility study. This Technical Report is intended to comply with disclosure and reporting requirements set forth in National Instrument (NI 43-101) of the Canadian Securities Administrators (including the NI 43-101 Companion Policy and Form 43-101F1). The respective certificates for the Qualified Persons can be found in Section 28.0.

2.2

Units and Currency In this report, all currency amounts are in Canadian Dollars (Cdn$) unless otherwise stated, with commodity prices typically expressed in US Dollars (US$). Quantities are generally stated in Système International d’Unités (SI) metric units, the standard Canadian and international practice, including metric tons (tonnes, t) for weight, and kilometres (km) or metres (m) for distance. Abbreviations and symbols used in this report are listed in the List of Abbreviations.

2.3

Inspection of Property André Allaire, Eng. of BBA visited the Detour Lake site on March 25, 2010. Maxime Dupéré, P.Geo. of SGS Geostat did a personal inspection of the Property between November 1 and 4, 2011. Patrice Live, Eng. of BBA did a personal inspection of the Property between January 4 and 5, 2012. Andre Allairé, Eng. of BBA was present regularly at site during the process plant ramp-up from July to November 2013 and did several personal inspections of the site.

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Detour Lake Mine NI 43-101 Technical Report

3.0

Reliance on Other Experts The sources of information found in this report, including data and supporting reports, were supplied by Detour Gold personnel, as well as documents included/referenced in section 27.0. The lead author of this Technical Report, André Allaire, Eng. of BBA is not qualified to provide comments on issues relating to mining and exploration titles and land tenure, royalties, permitting and legal, and environmental matters. The assessment of data pertaining to these sections (1.2, 4.0, and 20.0) relies on information provided by representative experts employed by Detour Gold, which otherwise has not been independently verified by the author. Detour Gold provided SGS Geostat with electronic files that included drill logs, survey and collar data, lithology, and assay results for the complete dataset that was used in the mineral resource estimate.

3.1

Disclaimer It should be understood that the mineral resources and reserves presented in this report are estimates of the size and grade of the deposits based on a certain number of drilling and sampling and on assumptions and parameters currently available. The level of confidence in the estimates depends upon a number of uncertainties. These uncertainties include, but are not limited to, future changes in metal prices and/or production costs, differences in size and grade and recovery rates from those expected, and changes in project parameters. The comments in this report reflect BBA’s best judgment in light of the information available at the time of preparation. BBA reserves the right, but will not be obligated, to revise this report and conclusions if additional information becomes known to BBA subsequent to the date of this report.

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Detour Lake Mine NI 43-101 Technical Report

4.0 4.1

Property Description and Location Location and Access The Property is located in northeastern Ontario with a very small portion extending into northwestern Québec. It is situated approximately 300 kilometres northeast of Timmins and 185 kilometres by road northeast of Cochrane (Figure 4-1). The centre of the Property is situated at approximately 5,540,000N, 590,000E, Zone 17, NAD 83 Datum within NTS areas 32E13. The Property is easily accessible all year long via Cochrane on provincial highway 652, followed by 34 kilometres of well-maintained gravel road. Figure 4-1

4.2

Detour Lake Property Location

Property Ownership and Agreements Detour Gold was incorporated on July 19, 2006 to acquire the Property and on August 21, 2006, the Company executed a Purchase Agreement with Pelangio Mines Inc. (“Pelangio”), whereby Detour Gold agreed to acquire the assets constituting the Property from Pelangio, subject to satisfaction of certain conditions set out in the Purchase Agreement. All conditions set out in the Purchase Agreement, including the completion of the Initial Public Offering, were fulfilled on January 31, 2007, and all the titles held by Pelangio to the Property were transferred to Detour Gold. The 627 km² Property forms one contiguous group of mining leases and claims in the District of Cochrane, with a small group of claims in Massicotte Township, Québec. The

4 February 2014

4-1

Property Description and Location

Detour Lake mine is located on the Mine Property. The summary of the Property is shown in Table 4-1 and Figure 4-2. Table 4-1

Summary of the Detour Lake Property

Description Purchased Claims (Individual) Aurora Property

Staked Claims

Mining Lease Documents

Patent Documents

10

1,744 13*

7,017

Sunday Lake Property (50 % interest)

3

1,321

Block A

3

940

Block A North Blocks B through E

9

Area (ha)

4 5

6,648

Gowest Property

3

1,003

Mine Property

8

Detour Gold Claims (ON)

105

386

165

Detour Gold Purchased Leases Total

293

6

3,312

4*

40,225

2

73

41

6

62,669

*Mining lease issuance pending for one application.

In September 2010, Detour Gold completed the acquisition of Conquest Resources Limited’s (“Conquest”) Aurora and Tie-in claim blocks (the “Aurora Property”) and entered into an Option and Joint Venture Agreement to acquire a 50% interest in Conquest’s Sunday Lake claim block (the “Sunday Lake Property”), located immediately south and east of the Detour Lake mine, respectively. In September 2013, Detour Gold had earned a 50% interest in the Sunday Lake Property. A list of the mining titles held by Detour Gold on the Property with their location, area, expiry date and royalties, along with a map, is provided under Appendix A. The Detour Lake mine is located on the Mine Property (33 km2), the site of the former Detour Lake open pit and underground mining operation, which produced gold between 1983 and 1999. The outer boundaries are surveyed and marked by a series of survey points located along the outer perimeter. The option on the Mine Property was exercised on October 30, 2008, when Detour Gold became the sole owner of all related surface rights, titles, and permits that were transferred from Goldcorp Canada Ltd. (“Goldcorp”) (successor to Placer). The patented parcels of land are the most secure form of land tenure and are subject to an annual mining tax payable to the Crown. The patented lands are described by the legal survey of individual mining claims and surveyed mining locations. The leasehold mining lands consist of 21-year mining leases issued for mining claims that have been legally surveyed as individual mining claims or defined by the perimeter survey of groups of mining claims. Each perimeter survey is given a CLM designation to describe the surveyed group of claims. Leaseholders are subject to an annual rental payable to the Crown. The Mining Act (Ontario) contains provisions for the renewal of 21 year mining 4-2

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Detour Lake Mine NI 43-101 Technical Report

leases. Applications for renewal are subject to review and consent by the Ontario Ministry of Northern Development and Mines (“MNDM”). The unpatented mining claims (staked claims) held by the Company do not confer upon the Company any right, title, interest or claims in or to the mining claims other than the right to proceed as is in the Mining Act (Ontario). Upon recording mining claims, the Company must perform and file exploration assessment work and apply on those claims assessment work credits to maintain them in good standing. The first unit of assessment work of $400/16 ha is required by the second anniversary date of the recording of the claim and an additional unit is required to be performed and filed for each year thereafter. Until a mining lease for the mining claims is issued, the Company does not have the right to remove or otherwise dispose of any minerals found in, upon or under the mining claim. The Company is currently in the process of bringing 24 mining claims to lease comprising an area of approximately 1,855 ha in two separate leases. A claim in Québec provides the stakeholder with a two-year right to explore within the claim holdings for any mineral substance with exceptions. After the initial two-year period claims can be renewed for an additional two-year term on certain conditions including that sufficient assessment work is performed on the contiguous claims. Figure 4-2

4 February 2014

Detour Lake Property Claim Location Map

4-3

Property Description and Location

4.3

Summary of NSR or Other Obligations To summarize, the Property is subject to the following net smelter return (“NSR”) obligations presented in Table 4-2. Prism Resources Inc. holds a 7.5% net profit interest on the Aurora and Sunday Lake properties. Effective November 28, 2012, the Company bought back Goldcorp’s 1% NSR on the Mine Property for $1 million. Table 4-2

NSR Obligations

Property

4.4

NSR Amount

NSR Holder

Buy-out Option

Blocks A through E except Block A North

1%

Goldcorp

Blocks A through E

2%

Franco-Nevada

$1,000,000 none

Mine Property

2%

Franco-Nevada

none

Purchased Claims (Individual)

2%

Individual Prospector

none

Gowest

1%

Gowest Gold Ltd.

none

Current Environmental Obligations In January 1995, Placer filed a mine closure plan (the “Mine Closure Plan”) with the MNDM. The former Detour Lake mine ceased operations in July 1999 and the underground workings and open pit were allowed to flood. All of the major buildings and infrastructure, including power lines, were removed during the period from 1999 to 2003. Physical reclamation of the mine site was substantially complete when Detour Gold acquired the Property. With Detour Gold exercising its option to purchase the Mine Property in October 2008, it became the proponent under the Mine Closure Plan as amended by the “Detour Lake Mine 2008 Closure Plan Amendment” dated June 6, 2008 (the “2008 Mine Closure Plan”) and submitted financial assurance (a letter of credit) to the MNDM in the amount of $6.6 million in support of its obligations under the 2008 Mine Closure Plan. Detour Gold filed a new mine closure plan (the “2010 Mine Closure Plan”) in August 2010 to reflect the scope of the new mine proposed in the feasibility study and environmental assessment studies. In September 2010, the Company issued a second letter of credit to the MNDM in the amount of $21.62 million, providing financial insurance regarding the new 2010 Mine Closure Plan. In October 2010, Detour Gold received notice from the MNDM of acceptance of the 2010 Mine Closure Plan and the associated closure bond for the Project. In January 2013, the Company issued an additional letter of credit to the MNDM in the amount of $5.17 million, which was accepted by the MNDM during the same month. The total financial assurance is currently at $33.4 million. As filed with the MNDM, the estimated costs of mine closure and ongoing monitoring are estimated at $69.6 million (refer to section 20.4). An amendment to the 2010 Mine Closure Plan is currently being compiled to update the MNDM on the as-built configuration of the Detour Lake mine. This application is expected to be filed in mid-2014 after consultation with Aboriginal communities.

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Detour Lake Mine NI 43-101 Technical Report

4.5

Permits in Place A number of operating permits had been issued in the name of Detour Gold, including a Provincial Environmental Compliance Approval for the new tailings system, a land use permit for road access (approximately 34 kilometres beyond Highway 652), a waste disposal permit (tailings facility), a landfill permit, an air permit, a number of water taking permits, a number of borrow and gravel pits permits and numerous forestry cutting permits for the development of the Detour Lake mine. In November 2010, Detour Gold received the Statement of Completion of the Class EA (Category C) for the Disposition of Rights to Crown Resources from the Ontario Ministry of Natural Resources (“MNR”). This approval, along with the approval of the closure plan, allowed Detour Gold to commence construction of the mining facilities for the Detour Lake mine. In addition to the above mentioned approvals, Detour Gold obtained the provincial Class EA for Temporary Power Supply (Diesel Generator of less than 5 megawatts; Category B), the provincial Class EA for Temporary Power Supply (Diesel Generator of less than 10 megawatts; Category B) as a contingency power supply and the individual EA for Permanent Power Supply (230 kV transmission line). The Company completed the Federal permitting process under Canadian Environmental Approval Act – CEAA. The Federal Minister of Environment approved the Comprehensive Study Report (“CSR”) on December 22, 2011. Federal permits were obtained for the temporary and permanent explosives plants.

4 February 2014

4-5

Detour Lake Mine NI 43-101 Technical Report

5.0

Accessibility, Climate, Local Resources, Infrastructure, and Physiography

5.1.1

Accessibility From the town of Cochrane, with a population of approximately 5,000 residents, the Property is easily accessible by the Detour Lake mine road, the northern extension of Highway 652. The first 151 kilometres on Highway 652 is paved surface, followed by 34 kilometres of well-maintained gravel surfaced road to the project site.

5.2

Climate and Physiography The climatological information on temperature and precipitation for the Property was taken from the average historical measurements from two Environment Canada meteorological stations located at Kapuskasing, Ontario and Matagami, Québec. Based on the data from these two stations, the mean annual temperature is estimated at 0.3°C, with average daily temperatures ranging from -18.8°C in January to 16.6°C in July. The average total annual precipitation is estimated at 851 millimetres with the greatest precipitation contribution occurring as rain during June through October. Prominent winds in the area are generally from the west throughout the year. A significant percentage of the winds in summer and fall come from the southwest. Winds from the west and northwest are prevalent in winter and spring. The mean annual wind speed is approximately 12.6 kilometres per hour. The topography of the site is subdued with maximum local relief of approximately 30 metres. The elevation ranges from approximately 260 to 288 metres above sea level. There is a pronounced north/south fluting of the landscape consistent with the general direction of the most recent glaciations in this area. Areas of higher relief are sparsely wooded with jack pine, black and white spruce, balsam fir, trembling aspen, and white birch. Areas that are slightly lower in relief are poorly drained and characterized by muskeg. There is very little bedrock outcrop and large areas of the Property are overlain by thick accumulations of glacial material that includes till and glaciofluvial material (poorly sorted sand with lenses of gravel). Numerous small streams linking elliptical lakes and ponds, generally oriented parallel to the pattern of glacial fluting cut the Property. Numerous small and shallow lakes occur on the Property, the largest being Sunday Lake, with a surface area of approximately 2.8 km2.

5.3

Local Resource and Infrastructure The region benefits from a strong contractor and supplier base to the mining industry. Skilled labour and suppliers are readily available in the nearby towns of Cochrane, Kapuskasing, Iroquois Falls, Timmins, and Kirkland Lake. The Company’s surface rights are sufficient for the entire mining operation. Nearly all the infrastructure for the new mine was completed at the end of 2012. It included the construction of a 230 kV transmission line, a processing plant facility, various mine site

4 February 2014

5-1

Accessibility, Climate, Local Resources, Infrastructure, and Physiography

buildings (mine services facility, bulk explosives plant, wash bay, fuel and lube island, etc.), a permanent camp, and new roads to connect the infrastructure buildings. During the greater part of the construction period, Detour Gold had established a temporary construction camp with a maximum capacity of approximately 1,300 dormitory rooms (at the site of the original camp from the past producing mine). The complex has been reduced to approximately 355 dormitory rooms and includes a kitchen, administrative offices, equipment storage, and water and sewage treatment plants. The permanent camp is located seven kilometres west of the mining operations. The complex includes 509 dormitory rooms, a kitchen, administrative offices, and a water and sewage treatment plant. Construction of the TMA continues to progress. The design plan for the tailings storage and waste stockpiles is developed to minimize the environmental footprint and is located in proximity of the open pit operation.

5-2

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Detour Lake Mine NI 43-101 Technical Report

6.0 6.1

History Ownership History In 1974, Amoco Canada Petroleum Company Ltd. (“Amoco”) commenced geophysical surveys on the Mine Property and identified an anomaly. Subsequent drilling confirmed the presence of a significant gold deposit. In 1978, Amoco signed a joint venture agreement with Campbell Red Lake Mines (“Campbell”) and Dome Mines Ltd. (“Dome”). By 1982, the joint venture, with additional drilling and a new resource estimate, made the decision to commence open pit mining and initiate underground development. The open pit mining started in 1983 followed by underground mining in 1987. In 1987, Campbell, Dome and Placer Development merged to become Placer Dome Inc. (“Placer”). Less than a year later, Placer acquired the remaining 50% of the Property that was still owned by Amoco. In December 1998, Pelangio-Larder Mines Limited (“Pelangio-Larder”) and FrancoNevada Mining Company Limited (“Franco”) (the “Detour Lake Joint Venture”) acquired the Mine Property from Placer Dome (CLA) Ltd. (“Placer”) (now Goldcorp) pursuant to an option and access agreement between the Detour Lake Joint Venture and Placer dated December 10, 1998, (the “Option and Access Agreement”). The Detour Lake Joint Venture also acquired certain parts of the Detour Exploration Lands surrounding the Mine Property pursuant to an assignment of the letter agreement dated as of September 28, 1998, between Pelangio-Larder and Placer. In May 2000, by way of statutory plan of arrangement, Marl Resources Corp. (predecessor to Pelangio) acquired substantially all of the assets of Pelangio-Larder. Those assets included Pelangio-Larder’s interest in the Detour Lake Joint Venture dated December 10, 1998, with Franco, predecessor in title to Newmont Mining Corporation of Canada Limited (“Newmont”). Pursuant to a purchase and sale agreement dated May 15, 2002, between Newmont and Pelangio, Pelangio completed the purchase of all of Newmont’s interest in the Detour Lake Joint Venture, subject to the retention of a 2% NSR by Newmont on the Mine Property and on certain claims staked by Pelangio (Blocks A to E). Newmont subsequently transferred its 2% interest to Franco-Nevada Corporation. Included in the Property interest purchased were the rights to purchase, each for $1 million, Goldcorp’s 1% NSR on the Mine Property and Goldcorp’s 1% NSR on certain parts of the land surrounding the Mine Property. In June 2002, Pelangio purchased the Purchased Claims from a prospector subject to the retention of a 2% NSR by the selling prospector. In September 2003, Pelangio granted Trade Winds an option to acquire a 50% interest in Block A, located immediately west of the Mine Property. Trade Winds fulfilled all the requirements to earn a 50% interest in Block A on December 31, 2006. On January 31, 2007, Detour Gold completed the purchase agreement with Pelangio and acquired all the

4 February 2014

6-1

History

Detour Lake assets, including Block A. A comprehensive Joint Venture agreement with Trade Winds was signed on April 8, 2009. On October 30, 2008, the Company exercised its option to purchase the Mine Property, which had previously been granted by Goldcorp pursuant to the Option and Access Agreement (as defined above), and acquired the Mine Property from Goldcorp pursuant to a purchase agreement dated April 14, 2008. In connection with the purchase of the Mine Property, Goldcorp held a 1% NSR on the Mine Property, which Detour Gold purchased for $1 million in November 2012. In September 2010, Detour Gold completed the transaction with Conquest pursuant to which Detour Gold purchased Conquest’s 100% interest in the Aurora Property for $2 million in cash and 100,000 common shares of Detour Gold; and entered into an option and joint venture agreement with Conquest that provided Detour Gold with the option to acquire a 50% interest in Conquest’s Sunday Lake Property by incurring $1 million in exploration expenditures over the subsequent two years. In 2012, this 2-year period was extended until September 2013. The Company has fulfilled its expenditures obligations and has earned a 50% interest in the Sunday Lake Property. In December 2011, Detour Gold completed the acquisition of Trade Winds. Detour Gold amalgamated with its wholly-owned subsidiary ‘Trade Winds’ effective January 1, 2014.

6.2

Exploration History In 1974, Amoco commenced exploration activities on the Mine Property with regional airborne geophysical surveys, as well as ground CEM (Crone electromagnetic), Radem and magnetometer surveys. These surveys achieved immediate success with the identification of a 2-kilometre long input anomaly with strong magnetic coincidence, which was originally named the “Detour 38 Anomaly”. In October 1974, Amoco drilled the first hole into the central portion of the Detour 38 Anomaly and intersected several interesting zones, including a 9-metre section containing 10-15% pyrrhotite and up to 1% chalcopyrite within a quartz vein system that would eventually be called the Main Zone. In 1975, a major exploration drilling program was undertaken, including the completion of over 47,444 metres of surface drilling, construction of a decline to the 120-metre level and underground drilling and sampling along this level. A winter road was also built from La Sarre, Québec to the project site. The results of this work successfully confirmed the presence of a significant gold deposit, which was estimated by Amoco to host 9.5 Mt at 0.207 oz/t (cut to 1 oz/ton), or 0.265 oz/ton (uncut), to a depth of 545 metres1. Despite this, a feasibility study carried out by Lummus Company of Canada Limited between 1976 and 1978 indicated negative results that prompted the joint venturing of the Property to Campbell and Dome. Campbell and Dome would each become 25% stakeholders in the Property and Campbell would be the operator.

1

These resource figures were not prepared under NI 43-101 and should not be relied upon to conform to current standards and definitions. As such, the data should be interpreted as unclassified historical resource estimates. 6-2

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Prior to 1979, drilling programs were mainly coordinated by Amoco and totalled 57,339 metres in 335 holes directed on targets located on the Mine Property, and 986 metres in six holes on Block A. Most of the drill holes completed on the Mine Property were from surface and focused in the area of the Main Zone where the Campbell Pit was developed. Between 1979 and 1982, Campbell completed additional surface and underground drilling for a total of 31,616 metres in 419 holes, and channel and grab sampling. As with Amoco, most of the drilling focused on the Main Zone but a substantial amount was directed towards quartz zones to the west. In 1982, a new resource estimate indicated a combined underground and open pit operation of 27.7 Mt grading 3.88 g/t Au1. A decision was taken to commence open pit mining at a rate of 2,000 tpd, and gradually replacing this with underground production over a five-year time frame. On the Block A property, between 1983 and 1984, Global Energy Corporation during an option held by Ingamar Exploration Ltd. drilled an estimated 15 holes. The drilling program returned narrow gold intersections from several closely spaced holes approximately 400 metres north of Lindberg Lake (west of the Block A deposit). In 1983, open pit mining started at Detour Lake but no reports, plans or production data related to the sampling, reserve and resource estimates or open pit mining have been located to date. From 1983 to 1987, open pit production totalled 3.0 Mt grading 3.25 g/t Au (313,070 oz). Approximately 1.6 Mt grading 1.40 g/t Au (70,652 oz) were blended with underground ore between 1986 and 1998 (Kallio, 2006) In 1987, underground mining commenced at the Detour Lake, coinciding with a merger between Campbell, Dome and Placer Development to become Placer Dome Inc. Less than a year later, Placer acquired the remaining 50% of the Property, which was still owned by Amoco. From 1987 to 1999, underground gold production is estimated at 9.1 Mt grading 4.98 g/t Au (1,464,431 oz). The above total was attained through a combination of mining methods including longhole stoping, cut-and-fill stoping, shrinkage stoping and level development. In 1995, a new zone referred to as the QK Zone was discovered. The operation was expanded to 3,750 tpd, but detailed engineering studies proved negative. The mine started experiencing significant production and grade problems. In 1998, the open pit mining resumed for a short time, extracting 644,000 tonnes grading 2.20 g/t Au. In July 1999, due to low gold prices and declining economics, Placer halted mining at Detour Lake and reclamation of the Mine Property was initiated. Total production (open pit and underground) over the 17-year life of Detour Lake mine is estimated at 1,764,986 oz of gold from the milling of just over 14.3 Mt of rock at an average head grade of 3.82 g/t Au and a mill recovery of 93.1%.

1

These resource figures were not prepared under NI 43-101 and should not be relied upon to conform to current standards and definitions. As such, the data should be interpreted as unclassified historical resource estimates. 4 February 2014

6-3

History

Over that period from 1987 to 1998, Placer’s Detour Mine Geology Department completed 435,002 metres in 4,219 holes from both underground and surface. After 1990, the bulk of the drilling tested the westerly extensions of the gold mineralization. Placer’s Exploration Department completed an additional 90,889 metres in 283 holes on the Mine Property and 62,147 metres in 133 holes on other parts of the Property, including a number of drilling programs in the area of the Block A deposit (including the M Zone). From 2004 to 2006, Pelangio drilled 127 holes (29,769 metres) directed towards a variety of exploration targets located mainly west of the former Cambell pit, including the M Zone near the west boundary with Block A, and the area north of Walter Lake. The exploration program led to the completion of a resource estimate with the concept of a combined underground and open pit mining scenario mainly for Detour Lake and the extreme east portion of Block A. From 2003 to 2011, Trade Winds completed approximately 134,000 metres of drilling on the Block A and Gowest properties.

6.3 6.3.1

Previous Mineral Resource and Reserve Estimates Detour Lake Table 6-1 summarizes prior mineral resource estimates made for Detour Lake (20052008). Table 6-1

Summary of Mineral Resource History

Source/Year

Kallio for Pelangio (2005)

Cut-off Grade g/t Au 0.65

Measured and Indicated Tonnes (millions) 2.48

g/t Au 2.00

Cont’d oz (Moz) 0.16

2.50/4.50

Inferred Tonnes (millions)

g/t Au

Cont’d.oz (Moz)

15.29

1.73

0.85

8.10

3.37

0.88

Kallio for Pelangio (2006)

0.85

20.0

2.14

1.38

35.4

1.80

2.04

Watts, Griffis and McQuat for Detour Gold (2007)

0.64

89.9

1.67

4.83

63.3

1.49

3.02

Watts, Griffis and McQuat/ BBA for Detour Gold (2008)

0.50

242.9

1.38

10.76

63.9

1.19

2.45

In September 2009, Detour Gold released the results of the pre-feasibility study for Detour Lake and in October 2009 filed a NI 43-101 compliant Technical Report (Met-Chem, 2009). SGS Geostat completed the block model and the resource estimation based on the information provided by Detour Gold. Grade interpolation was completed using ordinary kriging utilizing different capping levels for each mineralized domain. The open pit mineral reserve was estimated by BBA and is shown in Table 6-2. The optimized pit shell was generated using LG pit optimizer algorithm using the cost and economics parameters described in the pre-feasibility study. The LOM waste to ore ratio was estimated at 3.8 to 1.

6-4

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Detour Lake Mine NI 43-101 Technical Report

Table 6-2

September 2009 Mineral Reserve Estimate (using US$775/oz gold price and a cut-off grade of 0.60 g/t Au 2, 3

Resource Category Proven

Tonnes (millions)

Grade Capped (g/t Au)

Gold Ounces (000’s)

61.2

1.40

2,751

Probable

177.4

1.06

6,062

Total (P&P)

238.6

1.15

8,813

In May 2010, Detour Gold released the results of the feasibility study for Detour Lake and in June 2010 filed an NI 43-101 compliant Technical Report (BBA, 2010). SGS Geostat completed the block model and the resource estimation, based on the information provided by Detour Gold. Grade interpolation was completed using ordinary kriging (OK) utilizing different capping levels for each mineralized domain. The global mineral resource of the Detour Lake gold is shown in Table 6-3. Table 6-3

May 2010 Global Mineral Resource Estimate (cut-off grade of 0.50 g/t Au)2, 3, 4, 5

Resource Category

Tonnes (millions)

Grade Capped (g/t Au)

Gold Ounces (000’s)

Measured (M)

108.3

1.39

4,840

Indicated (I)

401.8

0.99

12,830

Total (M&I)

510.0

1.08

17,670

Inferred

133.6

0.88

3,430

The open pit mineral reserve was estimated by BBA and is shown in Table 6-4. The optimized pit shell was generated using LG pit optimizer algorithm using the cost and economics parameters described in the feasibility study. The LOM waste to ore ratio was estimated at 3.3 to 1. Table 6-4

May 2010 Mineral Reserve Estimate (using US$850/oz gold price and a cut-off grade of 0.50 g/t Au)2, 3

Resource Category Proven

Tonnes (millions)

Grade Capped (g/t Au)

Gold Ounces (000’s)

81.5

1.28

3,359

Probable

266.0

0.94

8,030

Total (P&P)

347.5

1.02

11,389

2

Mineral reserves are included within the mineral resources reported.

3

Capping grade estimated by domains and varies from 15 g/t to 50 m. g/t.

4

Mineral resources that are not mineral reserves do not have demonstrated economic viability.

5

The quantity and grade of reported Inferred resources in this estimation are conceptual in nature and there has been insufficient exploration to define these Inferred resources as an Indicated or Measured resource. It is uncertain if further exploration will result in upgrading them to an Indicated or Measured resource category. 4 February 2014

6-5

History

In January 2011, Detour Gold released an updated mineral resource and reserve estimate for Detour Lake, which incorporated new drilling data from the 2010 drilling campaign. SGS Geostat completed the block model and the resource estimation, based on the information provided by Detour Gold. The ordinary kriging (OK) block model used for the global mineral resources covered the area between sections 17,000E and 20,600E, extending an additional 500 metres to the west from the feasibility study block model. The global mineral resource for Detour Lake is shown in Table 6-5. Table 6-5

January 2011 Global Mineral Resource Estimate (cut-off grade of 0.50 g/t Au)2, 3, 4, 5

Resource Category

Tonnes (millions)

Grade Capped (g/t Au)

Gold Ounces (000’s)

Measured (M)

123.6

1.36

5,417

Indicated (I)

470.6

1.00

15,098

Total (M&I)

594.2

1.07

20,515

Inferred

190.3

0.84

5,144

The open pit mineral reserve was estimated by BBA and is shown in Table 6-6. The optimized pit shell was generated using the LG pit optimizer algorithm using the same cost and economics parameters described in the feasibility study report. The overall waste to ore ratio was estimated at 3.9 to 1. The increase in the strip ratio from the prior estimate was the result of a greater quantity of waste (including Inferred resources) contained within the new pit design due to insufficient drilling at the west end of the pit. Table 6-6

January 2011 Mineral Reserves Estimate (using US$850/oz gold price and a cut-off grade of 0.50 g/t Au)2, 3

Resource Category Proven

Tonnes (millions)

Grade Capped (g/t Au)

Gold Ounces (000’s)

93.7

1.29

3,886

Probable

355.8

0.96

10,974

Total (P&P)

449.5

1.03

14,860

In January 2012, Detour Gold announced its 2011 year-end mineral resource and reserve update for Detour Lake. The new estimate is based on the addition of 67,587 metres of drilling from the 2011 drilling program. The ordinary kriging (OK) block model used for the global mineral resources covers the area between sections 16,500E and 20,600E, extending an additional 500 metres to the west from the prior block model. Table 6-7 summarizes the global mineral resource using the same parameters as the January 2011 mineral resources and reserves estimate. 2

Mineral reserves are included within the mineral resources reported.

3

Capping grade estimated by domains and varies from 15 g/t to 50 m. g/t.

4

Mineral resources that are not mineral reserves do not have demonstrated economic viability.

5

The quantity and grade of reported Inferred resources in this estimation are conceptual in nature and there has been insufficient exploration to define these Inferred resources as an Indicated or Measured resource. It is uncertain if further exploration will result in upgrading them to an Indicated or Measured resource category.

6-6

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Detour Lake Mine NI 43-101 Technical Report

Table 6-7

2011 Year-end Global Mineral Resource Estimate (using a cut-off grade of 0.5 g/t Au)2, 3, 4, 5

Resource Category

Tonnes (millions)

Grade Capped (g/t Au)

Gold Ounces (000’s)

Measured (M)

124.5

1.36

5,424

Indicated (I)

554.3

1.00

17,836

Total (M&I)

678.8

1.07

23,261

Inferred

208.5

0.86

5,785

The open pit mineral reserve shown in Table 6-8 was estimated by BBA using the same detailed engineered pit design and cost parameters described in the Technical Report of March 2011. The LOM waste to ore ratio was estimated at 3.6 to 1. Table 6-8

2011 Year-end Mineral Reserve (using US$850/oz gold price and a cut-off grade of 0.50 g/t Au)2, 3

Resource Category

6.3.2

Tonnes (millions)

Grade Capped (g/t Au)

Gold Ounces (000’s)

Proven

101.6

1.29

4,222

Probable

368.4

0.96

11,351

Total (P&P)

470.0

1.03

15,573

Block A On February 14, 2011, Trade Winds completed a mineral resource update for the Block A property as outlined in Table 6-9. The mineral resource update did not include the portion of the mineral resources that crossed the boundary with the mine property. Table 6-9

February 2011 Block A In-pit Mineral Resource Estimate (using US$1,000/oz gold price and a cut-off grade of 0.50 g/t Au)4, 5

Resource Category

Tonnes (millions)

Grade Capped (g/t Au)

Gold Ounces (000’s)

Indicated

52.9

0.98

1,667

Inferred

20.7

1.00

0.667

2

Mineral reserves are included within the mineral resources reported.

3

Capping grade estimated by domains and varies from 15 g/t to 50 m. g/t.

4

Mineral resources that are not mineral reserves do not have demonstrated economic viability.

5

The quantity and grade of reported Inferred resources in this estimation are conceptual in nature and there has been insufficient exploration to define these Inferred resources as an Indicated or Measured resource. It is uncertain if further exploration will result in upgrading them to an Indicated or Measured resource category

4 February 2014

6-7

Detour Lake Mine NI 43-101 Technical Report

7.0 7.1

Geological Setting and Mineralization Regional Geology The Property is located within the northwestern portion of the AGB. The AGB lies in the eastern part of the Wawa-Abitibi sub-province, a Neoarchean granite-greenstone subprovince in the southern Superior Province of the Canadian Shield craton. The AGB is defined by multiple east-west trending synclines dominated by volcanic assemblages with intervening domes of synvolcanic and/or syntectonic plutons. The AGB is one of the world’s richest mining areas, producing gold, copper, zinc, silver and iron from the Timmins, Kirkland Lake, Rouyn-Noranda, Val d’Or, Mattagami and Chibougamau camps, as well as the Detour Lake area. The northernmost part of the ABG runs covers across the Property and runs eastward beyond Mattagami, Québec. Limited outcrops are observed on the Property, which is mostly covered by glacial till, marshes and wetlands. Detour Gold carried out regional mapping to the north, east, and south of the Detour Lake mine from 2009 to 2013. The geological interpretation is principally based on this mapping and the logging and/or re-logging of historical and recent diamond drill holes from all Detour Gold’s drilling programs, and from historical information from the former Detour Lake mine. The supracrustal lithologies observed on the Property are grouped into six main units (Figure 7-1, Figure 7-3 and Figure 7-4): 

Deloro Assemblage (“DA”) volcanics: Lower Detour Lake Formation (LDLF) and Upper Detour Lake Formation (UDLF);



Caopatina Assemblage (CA) sediments;



Intrusive rocks;



Tonalitic complex;



Opatica gneissic basement; and



Proterozoic-age diabase dykes.

Supracrustal rocks within the Detour Lake area comprise a thick 2.72 Ga old sequence of mafic to ultramafic lithologies, which are predominantly volcanics and referred to as the DA. The DA occurs within regional synclinal-anticlinal folds structures traced for over 30 kilometres across the Property and is in structural contact to the south with the younger sediments of the 2.69 Ga CA (Oliver et al., 2012). The supracrustal rocks are bounded to the north and west by the Opatica basement gneissic rocks. To the east and south, the DA is intruded by several large, weakly foliated granodioritic to tonalitic intrusions which are intersected by numerous local felsic to mafic dykes and sills and younger regional Proterozoic diabase dykes. These Proterozoic dykes, which are identified at the regional scale, are locally intruded into 120º to 145º azimuth trending faults with offsets that are typically less than tens of metres. The northern contact between the DA and the CA is characterized by a regional scale thrust fault, referred to as the Sunday Lake Deformation Zone (“SLDZ”), which has been 4 February 2014

7-1

Geological Setting and Mineralization

traced for over 100 kilometres regionally (west of the Property to well into Québec). The east-west SLDZ extends for over 30 kilometres on the Property (Figure 7-1). The reconnaissance scale aero-magnetic data (Ontario Geological Survey (OGS) Geophysical Data Set 1062) clearly defines a linear feature that positions the SLDZ at the northern contact of the CA sediments (Figure 7-2). The structures of the SLDZ are spatially related to most of the gold mineralization observed in the Detour Lake mine and Block A deposit. The southern contact between the DA and CA is marked by the Massicotte Deformation Zone (“MDZ”) and the Lower Detour Deformation Zone (“LDDZ”), zones of strong regional faulting. Both of these east-west trending deformation zones extend across the Property for over 30 kilometres. Based on geochronological evidences gathered at Detour Lake by Oliver et al. (2012), the DA, north of the SLDZ, is sub-divided into: the Upper Detour Lake Formation (“UDLF”), a dominant tholeiitic basaltic volcanic assemblage (mainly high-Mg massive and high-Fe pillowed flows) extending across the Property; and the Lower Detour Lake Formation (“LDLF”), an ultramafic-dominant komatiitic and high-Mg tholeiitic volcanic and intrusive assemblage of fairly limited width. The LDLF komatiitic lithologies in contact with the SLDZ are highly deformed and altered into talc-chlorite schist. The contact is highly mylonitized, mineralized and silicified and hosts a strongly deformed felsic to intermediate dyke-like body known locally as the Chert Marker Horizon (“CMH”). The CMH is a mineralized stratigraphic marker in the Detour Lake area and was the focus of the historic gold production. All the volcanic units have a general east-west strike with near-vertical dips. The CA is a poorly to well laminated metasedimentary unit (argillites, greywackes and quartz wackes) and mafic volcaniclastics. There is no significant gold mineralization associated with this unit. All these rock units are intruded by numerous narrow felsic to mafic dykes. The dykes can have a variety of colours and textures ranging from light to dark coloured and aphanitic to feldspar porphyritic. Intermediate dykes are less common and are predominantly fine-grained and locally porphyritic. Most dykes have east-west trends, parallel to sub-parallel to the main foliation. The timing and exact relationship of these dykes are uncertain, although a feldspar-phyric felsic dyke cutting mafic volcanics in the former Campbell pit yielded an age of 2722 +3/-2 Ma (Marmont & Corfu, 1989). The dykes are generally not foliated and are associated with the same structural control as the quartz veins. According to Barclay (1993), some of the felsic dykes pre-date the gold mineralization. Several intermediate intrusives have been mapped on the Property but their compositions have not been determined. Large tonalitic to granodiorite intrusions are mapped at the eastern end of the Property and through the Sunday Lake Property. These intrusives are weakly foliated and distinctly tonalitic in composition. The intrusion shifts to a more granodioritic composition within 300 metres of its contact. An epidote-albite-andraditepyrite-pyrrhotite contact aureole is locally well developed at the contact with supracrustal rocks and extends for approximately 200 metres into the enclosing supracrustal rocks. The contact aureole is locally associated with discontinuous gold and copper 7-2

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Detour Lake Mine NI 43-101 Technical Report

mineralization (Hole DGE-08-317 returned 0.4 g/t Au and 0.47% copper over 4.0 metres and DGS10-993 returning 1.44 g/t Au over 7.0 metres). The rocks to the north, west and southwest of the Property belong to the Opatica subprovince, a wide belt of amphibolite-facies plutonic gneisses. Geophysical interpretation indicates that they are in shallow north dipping and south verging structural contact with younger volcanics of the DA. Figure 7-1

4 February 2014

Regional Geology Map (Detour Lake Property)

7-3

Geological Setting and Mineralization

7-4

Figure 7-2

Second Derivative Aeromagnetic Data of the Detour Lake Property (OGS Geophysical Data Set 1062)

Figure 7-3

Geology of the Detour Lake Mine and Block A Deposit

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Detour Lake Mine NI 43-101 Technical Report

Figure 7-4

4 February 2014

Geological Sections 19,360E (A-A’), 18,500E (B-B’) and 17,540E (C-C’) for Detour Lake and 16,340E (D-D’) for Block A

7-5

Geological Setting and Mineralization

7.2

Detour Lake Mine and Block A Stratigraphy The following sub-sections describe the stratigraphy observed at the Detour Lake mine and Block A deposit. Lower Detour Lake Formation (LDLF – Deloro Assemblage) The LDLF is a thick sequence of mafic and ultramafic flows, sills, and dykes which form the base of the DA. This LDLF is not intersected in the Block A area. This sequence forms the core of a wide anticlinal structure partly truncated to the west by the SLDZ but reappearing west of section 17,500E of the mine grid. The ultramafic units of the LDLF include komatiitic flows showing very rarely preserved spinifex textures and pyroxenites, which form thick sills. Abundant fine-grained gabbroic units and mafic volcanics are also observed in the LDLF. The upper contact of this sequence is characterized by a highlystrained mineralized zone (CMH). Major rock types in the LDLF include: 

7-6

Chert Marker Horizon (term used historically): The CMH is associated with a silicified intermediate dyke occurring within a highly strained, silicified and mineralized zone at the contact between the overlying massive basaltic volcanic sequence (usually altered pillow flow) and the underlying deeply altered mafic/ultramafic sequence. The past operations mine geologists interpreted this unit as either a highly strained cream to buff felsic intrusion or as a true chert horizon. An age determination of 2725.1 ± 1.4 Ma indicates the CMH is a stratigraphic unit at or near the contact between the LDLF and the UDLF. The CMH is clearly calc-alkaline in geochemical composition with accessory zircon and apatite (up to 73% SiO2 and 130 ppm Zr) and commonly ranges between 0.5 to 2.0 metres in thickness. Gold values and sulphide contents are significantly 4 February 2014

Detour Lake Mine NI 43-101 Technical Report

enhanced within this unit compared to all other auriferous units at Detour Lake. The CMH was one of the principal host rocks for the gold produced at the former Detour Lake mine between 1983 and 1999. This unit is not observed in the Block A deposit. 

Mafic Flow Contact Unit (Chloritic schist): This thin 5 to 20 metres-thick flow unit is commonly observed in the immediate hanging wall of the underlying ultramafic assemblages at the Detour Lake mine. It is fine grained, light to dark green black and lacks significant matrix feldspar. It is generally foliated with chloritic alteration and locally potassic alteration. It does not generally contain sulphides.



Ultramafic Flows and Sills: This unit is comprised of a thick sequence of ultramafic flows with locally preserved spinifex textures, and coarse grained pyroxenite and finer grained ultramafic sills. The intrusive units have conformable contact relations to the other volcanic units. The sills are generally strongly altered in a fine to medium-grained massive talc-chlorite schist characterized by a distinct greasy feel. Occasionally, it has flow-like and/or breccia texture with various sizes of rock fragments set in a dark matrix. Fault zones are commonly present in this unit. Gold mineralization hosted in this unit is in the dilatational jog or flexure zone in the area of the former Campbell Pit (eastern part of the Detour Lake mine); and is intruded by numerous quartz feldspar porphyry felsic dykes. Again this unit is not observed in the Block A deposit.



Mafic volcanic: This flow unit is to the south of the talc-chlorite alteration zone of the Detour Lake mine. It is generally dense green-black, lacking significant matrix feldspar. Generally, foliated mafic minerals can be coarse to very coarsegrained forming a porphyritic texture. Various degrees of potassic (biotite) alteration can be locally present. Some short intervals of this unit show laminations. It contains very little gold mineralization.



Megacryptic diorite: This unit has coarse to very coarse feldspar phenocrysts set in a dark, fine-grained matrix, and locally may show foliation. In the LDLF, it is always associated with the mafic volcanic unit. Historically, it was described as part of the volcanic assemblage but recent work by Oliver et al. (2012) shows that it is a mega-cryptic diorite sill.



Mafic sills and dykes: The mafic sills and dykes are represented by abundant mafic (gabbroic) intrusions, finer grained flows, and dykes. Mafic intrusions may be strongly magnetic, containing 10 to 15% disseminated magnetite grains. The gabbroic dykes are mainly observed in the LDLF.

Upper Detour Lake Formation (UDLF – Deloro Assemblage) The UDLF volcanic rocks consist of a thick sequence of high-Mg tholeiitic basaltic massive flows and high-Fe tholeiitic pillowed flows that have the chemical affinities of arcrelated tholeiites. In the mineralized corridor of the Detour Lake mine and the Block A

4 February 2014

7-7

Geological Setting and Mineralization

deposit, these rock types are part of the hangingwall sequence and host the majority of the gold mineralization. The major rock types include: 

Pillow Flows: These are common throughout the Detour Lake mine and Block A areas, extending across the entire Property through the Block A area. This unit is characterized by pillow selvages, the formation of hyaloclastite, and vesicles filled by calcite. It is fine to medium-grained and usually shows foliation. The intensity of the potassic alteration varies from weak to strong. Pillow cusps and margins are preferentially altered with secondary biotite and albite, and pyritepyrrhotite-quartz assemblage (with local minor chalcopyrite) exhibiting an increase in intensity proximal to mineralized strained zones. Mafic (iron-rich) hyaloclastites are present in the Calcite Zone area, between approximately sections 18,800E to 18,200E, where they commonly have a brecciated texture. This rock unit contains abundant shardy centrimetric scale fragments frequently embedded within calcite with lesser iron carbonate-rich matrix infill. Chlorite alteration was observed in hyaloclastite fragments, along pillow margins and around calcite-filled vesicles. In rare instances, these units are weakly stratified. These hyaloclastites appear to be a favourable host to the gold mineralization.

7-8



Massive Flows: These units are generally grey in color, fine to medium grained with local porphyritic texture, and usually weak to moderately foliated. Local gradational changes in crystal size are common. Several very massive magnesium-rich tholeiitic flow sequences are present in the hangingwall sequence of the Detour Lake mine and Block A deposit. Massive flows typically contain 12-15% matrix plagioclase with 85% recrystallized mafic minerals (actinolite-hornblende), commonly occurring as 2-4 millimetres elongate interlocking recrystallized lathes. Pillow-structure, hyaloclastite and vesicles filled by calcite may be present locally. Calcite aggregates along foliation trends and calcite veinlets parallel/sub-parallel to foliation are quite common, usually with chloritic and/or biotite alteration haloes around the veins/veinlets. In the massive flows, gold occurs as free gold and is generally associated with 5 millimetres to 1 metre thick quartz veins/veinlets containing 80 x 80 metres) and in 2010 a 40 x 40 metre drill spacing pattern was initiated. This work was completed up to November 2011 by Trade Winds and continued by Detour Gold commencing in January 2012. This delineation drilling totalled 109,718 metres in 329 DH by Trade Winds. In 2012 Detour Gold drilled 49,158 metres in 156 holes. The Block A deposit has now been drilled on a 40 x 40 metre drill spacing from section 15,240E to 16,800E from surface to a depth of approximately 500 metres. For all Block A drilling programs, the true width is estimated to be 65% to 75% of the drilled length. Actual true width is dependent of the inclination and direction of the hole when intercepting the mineralized zone.

10.3 Exploration Drilling Programs Detour Gold completed the following exploration programs: 

2008: 12,054 metres in 38 holes peripheral to the Detour Lake mine;



2011: 5,025 metres in 22 holes targeting the vicinity of Detour Lake mine, the Sunday Lake Property and LDDZ (in the Lower Detour area);



2012: 5,061 metres in 17 holes targeting the Lower Detour area; and



2013: 26,765 metres in 80 holes targeting the Lower Detour area and Sunday Lake Property.

The 2011 drilling program targeted a prior gold intercept of 53.0 g/t over 3 metres (hole 519-059) on the LDDZ, and several IP anomalies on the Sunday Lake Property. The last 4 February 2014

10-3

Drilling Programs

drill hole of the program intersected 22.6 g/t Au over 1 metre (at a depth of 120 metres) just above the historic intercept of 53.0 g/t Au over 3 metres. In 2012, Detour Gold completed 5,061 metres in 17 holes targeting the LDDZ in the Lower Detour area. A fence of holes was drilled in the area of hole 519-059. The data collected indicated the presence of a 100-metre wide shear zone with strong biotite, sericite, and silica alteration. From the fence line, the best intersections were 13.0 g/t Au over 1 metre and 0.72 g/t Au over 4 metres. In 2013, Detour Gold completed 25,067 metres in 74 holes targeting the Lower Detour area. The best intersections included 17.33 g/t over 4.4 metres (Zone 75) and 10.25 g/t over 4.5 metres (Zone 58N). Detour Gold also completed 6 holes in the vicinity of Sunday Lake.

10.4 Other Drilling Programs Detour Gold completed the following technical holes on the property: Table 10-2

Technical Drilling on the Detour Lake and Block A Properties Meterage Completed on Detour Lake Geotech (Pit Slope)

Drilling Programs

Geotech (Environment) Holes

Metallurgy & Comminution

Metres

Holes

Condemnation

Metres

Holes

Metres

Holes

Metres

2007

8

2,889

-

-

13

4,092

-

-

2008

-

-

49

1,014

-

-

-

-

2009

-

-

83

826

10

4,382

-

-

2010

1

315

21

238

-

-

35

8,665

2011

-

-

-

-

-

-

-

-

2012

8

1,899

-

-

16

3,253

Total

17

5,103

153

2,077

39

11,727

35

8,665

Meterage Complete on Block A 2012-13

10

2,360

17

2,915

10.5 Drill Hole Survey and Drill Core Recovery Detour Gold follows standard procedures for drill hole survey and logging procedures. The hole collars including foresights and backsights were laid out by Talbot Surveys Ltd. (“Talbot”) using the differential GPS (DGPS) Topcon GR3 with a Nikon total station. The Universal Transverse Mercator (UTM), 1983 North American Datum (NAD83) system was used to record position data. Survey data was converted to Mine Grid for compatibility with the historical data. Occasionally when Talbot was unavailable, hand-held GPS units or compass and chain methods were used to locate collar pickets, which were inadvertently moved or destroyed. For the reconnaissance drilling program, drill hole collars were surveyed by GPS units.

10-4

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Detour Lake Mine NI 43-101 Technical Report

The above mentioned procedure was passed onto Trade Winds in late 2009 and this was accepted as their standard procedure starting in 2010 for Block A. Once the drill rig was positioned on the planned location, it was lined up using a Reflex GPS casing alignment instrument working within +/- 0.2 to 0.5 degrees of accuracy. After a hole was completed and the rig moved off drill site, the casing was covered with a steel cap and a wooden marker was placed next to the casing with the hole collar identification. Talbot returned to site every second week and surveyed the casing locations, as well as the azimuth and inclination of the holes drilled during this period. Measurements were done at the top of the casing (usually sticking out 15 centimetres above ground). The downhole surveying was recorded at 30 or 60 metres intervals by the drill contracting company using a Reflex EZ-Shot, which recorded azimuths and inclinations. Although magnetic minerals affected the Reflex instrument, it was for the most part adequate in determining the deviation of the drill hole while it was in progress. Immediately after the drill hole was completed, surveys of the direction and dip changes were carried out using a Reflex Maxibor II instrument. The instrument is based on optical measurements of direction changes and gravimetric measurements of dip changes. After setting the starting azimuth, the instrument was lowered down the hole and readings taken every 3 metres on the way back up. Once Talbot had surveyed the casing, the correct azimuth and inclination were entered into the Maxibor data to adjust the downhole readings. Maxibor readings are missing for several holes, because either the equipment was in for repair or the rods were sufficiently bent or bowed to prevent the instrument going down the hole. As of early 2010, the decision was made to eliminate the use of the Maxibor check surveys since the results were comparable with the Reflex instrumentation. The diameter sizes of all of the core samples are NQ (2-inch diameter core). Drill core is placed in wooden core boxes sealed with fencing wire (fibre tape since early 2011) and delivered twice a day to the assigned Detour Gold core shack. In general, core recovery exceeds 95% with losses generally occurring within the first few metres of bedrock or when going through a fault zone. Core recovery during the Trade Winds programs on the delineation drilling for Block A was reported to be 98.9%. Rock Quality Designation (“RQD”) measurements indicate that the hangingwall rock units (mafic volcanics) are very competent. The footwall units, occurring as they do in an active structural zone, has varied RQD measurements ranging from poor to good. All the above processes were followed for all Detour Gold exploration drilling programs except all holes drilled in these programs used hand held GPS units to “spot” the collar position and were verified with field positioning in the local grid. Once the drill rig was positioned on the planned location, it was lined up using a Reflex GPS casing alignment instrument working within +/- 0.2 to 0.5 degrees of accuracy. After a hole was completed and the rig moved off drill site, the casing was covered with a steel cap and stamped with the hole number. A wooden marker was placed next to the casing with the hole collar identification. Talbot was not engaged to survey in these holes.

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10-5

Drilling Programs

10.6 Mine Grid The original surface and underground survey control for Detour Lake was done by Placer who set up a local grid co-ordinate system. The conversion from surface UTM to mine grid, as supplied by Talbot is as follows: 

The mine grid is based on UTM NAD 83 SCRS (UTM Projection Zone 17);



Rotation: 1°06ʹ34" (1.109444);



False Easting: 19,323.72 = 591,594.493 metres;



False Northing: 20,486.88 = 5,541,400.36 metres;



False Elevation: 6,283.71 = 287.676 metres; and



Scale: 0.999644.

The difference from true north and magnetic north is 12°37’ west. Current survey control for exploration drill holes at the Detour Lake mine, Block A, and Gowest Property is based on the UTM NAD 83 grid. Coordinates are also converted to mine grid for compatibility with the operation. All operation and resource work is conducted in mine grid coordinates, with elevation referred as “EL”.

10-6

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Detour Lake Mine NI 43-101 Technical Report

11.0 Sample Preparation, Analyses, and Security Sample preparation, analyses and security have varied considerably since the start of the exploration work in the late 1970s. Kallio (2006) completed an in-depth review of the sample preparation, analytical, and quality assurance and quality control (“QA/QC”) procedures for the drilling period prior to 2004 and for the 2004 to 2006 period by Pelangio. WGM (2008a and 2008b) described the sample preparation and analytical procedures for 2007-2008 and Met-Chem (2009) for part of 2009, and BBA (2010, 2011, 2012) for 2009-2011. The QA/QC procedures for the 2007 to 2012 period were managed by Thon Consulting on a daily basis. Lynda Bloom from Analytical Solutions Ltd (“ASL”) was responsible for the complete review of the 2007 to 2012 QA/QC programs. This section summarizes information on sample preparation, analyses and security (QA/QC) reported by Kallio (2006), WGM (2008a and 2008b), Met-Chem (2009), BBA (2010, 2011, 2012) and ASL (2009a, 2009b, 2009c, 2010a, 2010b, 2011 and 2012). The latest report from ASL for Block A is included in Appendix B. Additionally, this section summarizes information on sample preparation, analysis and QA/QC completed on Block A, which was previously operated by Trade Winds (WGM, 2011). For pre-2007, refer to Kallio (2006) for a detailed description of the sample preparation, analytical and QA/QC procedures for Detour Lake.

11.1 Core Sampling Procedures and Securities This section describes core sampling procedures that have been in place since Detour Gold acquired the Property in 2007. It applies to drilling completed on the Detour Lake and Block A deposits, and all regional exploration work as carried out by Detour Gold. All work pertaining to production sampling and grade control at the Detour Lake mine will be discussed in Section 24. All drill core handling is done on site with the logging and sampling processes conducted by employees and contractors of Detour Gold. All the information is collected using a Microsoft Access database developed for Detour Gold (except for the first 19 drill holes of 2007). Drill core is placed into wooden core trays at the drill, with depths of each run marked on wooden blocks and inserted into the trays by the drill crew. These trays are collected by company geotechnicians and delivered to the geology facility on site. Core handling consists of: 

Geological logging;



Lithology, veining, mineralization, alternation, structure;



Marking out samples;



Measuring core recoveries/RQD’s;



Photographing core/tagging boxes with hole id’s and meterage;



Measuring rock strengths;

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11-1

Sample Preparation, Analyses, and Security



Marking out fractures;



Marking metre intervals between runs;



Cutting core for sampling;



Sampling core;



Shipping; and



Racking and storage.

All logging and marking of samples is done by Detour Gold’s geologists. Photographing, recovery, fractures, and rock strengths measurements are carried out by geotechnicians under geological supervision. All data entry is done on individual databases capable of synchronizing with a master database through the Company’s network. These individual databases are synchronized daily. All core is systematically sampled, following the procedure outlined below: 

Mineralized/potentially mineralized zones are recorded;



Visible gold broken down into half metre samples for pulp metallic analyses;



Core is fitted together in the box, and a wax pencil is used to scribe a line along the core, using the core box edge as a guide. The scribe line is used to orient the core in the diamond saw, and the top half of the core is always put in the sample bag. The portion to be saved is fitted back into the core box to be kept as a permanent record;



Samples are marked both on core and corresponding sample tags and bags;



All core is sampled for entire borehole top to bottom in one metre intervals with the exception of screen metallics, which are sampled at half-metre to maximum of 1 metre intervals;



Samples are bagged and numbered by a lab technician and double checked by another lab technician for accuracy;



All samples are logged with the sample number, from-to interval, and type of sample (rock or QA/QC sample). Additional information such as lithology, mineralization and veining are subsequently merged with sample data;



Samples are checked again prior to shipping for accuracy before being released;



The database is programmed to prompt the geologist during sampling to enter standards, blanks and duplicates at certain intervals;



Lab technicians use sample reports generated by the database to verify correct standards and sequencing in samples; and



Shipments are also kept track of through the database, with capability of pulling any shipment report done by Detour Gold.

All logging data is synchronized to the main field database via network connection. For each hole, the geologist prints a detailed log of the hole for field archives and updates the geological sections. A summarized geological description is also sent to the project manager. Once a week, the main field database is backed up on the corporate server 11-2

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Detour Lake Mine NI 43-101 Technical Report

and also uploaded to a secured FTP site for the database manager (Thon Consulting) in Smithers, British Columbia. For shipping, groups of 10 samples are placed in rice bags and shrink-wrapped on pallets. Rice bags are shipped directly from site to a commercial laboratory for preparation and assaying. A hard copy of the sample list is given to the driver and the digital shipment paperwork is emailed to the laboratory and to Detour Gold’s database manager. At the laboratory, SGS Minerals verifies all samples in the bags and emails the Detour Lake site to confirm that all samples on the list were received in good order. Detour Gold has compiled a complete inventory of the historical core on site. Much of the early historic drill core is in deteriorating condition due to the rotting of the core trays. On a regular basis, all core boxes in which samples have been collected are placed in steel core racks at the Detour Gold core storage facility located approximately 400 metres away from the core shack facility. The core storage facility is not guarded. SGS Geostat validated the core sampling procedures used by Detour Gold as part of an independent verification program. SGS Geostat concluded that the drill core handling, logging and sampling protocols used by Detour Gold are at conventional industry standard and conform to generally accepted best practices.

11.2 Analytical Laboratories For the drilling programs completed prior to 2007 on Detour Lake and prior to 2012 for Block A, the assaying was completed at a variety of commercial laboratories but also at other laboratories such as the Dome Mine in Timmins, Ontario and during the former Detour Lake mining operation at the Detour Lake Mine assay laboratory. The commercial laboratories included: Assayers Limited and X-Ral Laboratories in Rouyn, Québec; Swastika Laboratories Ltd. in Swastika, Ontario; Bondar Clegg in Ottawa, Ontario; Chemex Labs Ltd. in Mississauga, Ontario; Accurassay Laboratories (“Accurassay”) in Thunder Bay, Ontario; and ALS Chemex Labs Ltd. (“ALS Chemex”) in Vancouver, B.C., and Val-d’Or, Québec. From 2007 until 2012, all samples collected by Detour Gold for Detour Lake and the 2012 Block A campaign were prepared by SGS Minerals at its laboratory facilities in Garson and Don Mills, Ontario, and analyzed at its laboratory in Don Mills, Ontario. Check assays were also sent on a regular basis to ALS Chemex in Vancouver, B.C. Both the SGS Minerals and ALS Chemex laboratory facilities are well recognized and ISO-accredited. Prior to 2012, samples collected by previous owners on the Block A property were sent to ALS Minerals in Val d’Or, Québec; ALS Minerals in Timmins, Ontario, or Activation Laboratories Ltd. (“Actlabs”) in Timmins, Ontario. From 2008 to 2013, Detour Gold sent all of its regional exploration samples to Accurassay (accredited with ISO/IEC 17025) in Timmins for sample preparation and to Thunder Bay for analysis. For the 2011 drill programs and infill sampling program (previously un-assayed core), Trade Winds used the services of Actlabs for all preparation and assay requirements. 4 February 2014

11-3

Sample Preparation, Analyses, and Security

11.3 Sample Preparation and Analysis 11.3.1 Sample Preparation and Analysis for Historic Data For the pre-2007 campaigns, sample preparation and assay methods have varied considerably over time and are summarized by Kallio (2006). Crushing, pulverization and size of assay charge varied from half assay ton (equivalent to 15 g) to 50 g. Several programs included pulp and metallic sieve assaying for certain samples that were observed to contain visible gold, or for samples, which initially returned high grade values. For Pelangio drill programs conducted between 2004 and 2006, sample preparation and assaying varied depending on the commercial laboratory used for the process. From January to September 2004, the samples were processed by ALS Chemex of Mississauga, Ontario and the protocol used included dry crushing of samples to > 70% passing 10 mesh (2 mm), riffle splitting and pulverization of 250 g sub-samples to > 85% passing 75 μm then fire assaying of one assay ton sub-samples (30 g). Between October 2004 and May 2005, samples were sent to Accurassay and the protocol used included crushing to 90% passing 10 mesh then splitting of a 30 g sub-sample pulverized to -150 mesh (106 μm). Analysis was usually done with the fire assay technique except for interval containing visible gold or elevated values on initial analysis, which were conducted by pulp and metallic screen procedure using 1 kg split for 2004 then total pulverization during 2005. For the 2006 program, samples were processed at Swastika Laboratories using dry crushing to > 90% passing -10 mesh, riffle splitting and pulverization of 350 g sub-samples. The analysis was conducted using fire assay of one assay tonnes (30 g) sub-samples then using pulp and metallic screen procedure for sample with visible gold. 11.3.2 Sample Preparation From 2007 to 2012, Detour Gold contracted SGS Minerals for their analytical needs for Detour Lake and Block A. The routine sample preparation (SGS Code CRU25) included crushing the entire half-core sample received at the lab to 90% passing -10 mesh (2 mm) and subsequent riffle splitting to obtain a 500 g subsample. Each 500 g subsample was then pulverized in a chromium steel mill to 90% passing 200 mesh (75 μm) and subsampled again to obtain a 50 g pulp (SGS Code PUL46) for assaying. For Block A, samples by Trade Winds were sent to ALS Minerals (Val-d’Or and Vancouver) from 2003 to 2010. The routine sample preparation included crushing the entire half-core sample received at the lab to 70% passing -10 mesh (2 mm) and subsequent riffle splitting to obtain a 1 kg subsample. Each 1 kg subsample was then pulverized in a chromium steel mill to 85% passing 200 mesh (75 μm) and sub-sampled again to obtain a 50 g pulp (Au-AA24) for assaying. For 2011, Trade Winds sent their samples to Actlabs where the preparation procedure was very similar to the one used in 2010. From 2008 to 2013, Detour Gold contracted Accurassay in Timmins for their analytical needs for all regional exploration. The routine sample preparation included drying and crushing the entire half-core sample received at the laboratory to 75% passing -8 mesh 11-4

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Detour Lake Mine NI 43-101 Technical Report

and subsequent Jones riffler splitting to obtain a 500 g subsample. Each 500 g subsample was pulverized to 85% passing 200 mesh using a ring and puck pulverizer, and sub-sampled again to obtain a 50 g pulp for assaying. 11.3.3 Gold Analysis for Detour Lake Starting in 2007, routine gold analysis for the Detour Lake deposit was done using fire assaying with atomic absorption spectroscopy (AAS) finish (SGS Code FAA515) then later inductively coupled plasma atomic emission spectroscopy (ICP-AES) finish (SGS Code FAI505 and FAI525). Where the gold assays exceeded 10 g/t Au, the fire assay was repeated with a gravimetric finish (SGS Code FAG505). All samples with visible gold identified during the field logging procedure went directly to the metallic screen procedures (SGS Code FAS30K and FAS31K) using a nominal 500 g split of the original 10 mesh sample (2 mm). All routine assayed samples (fire assay atomic absorption or fire assay-gravimetric) returning values of 5 g/t Au or greater on the first analysis were reanalyzed using the metallic screen procedure. For the metallic screen procedure, the sub-samples were screened at -150 mesh (106 μm), and then both the coarse and fine fractions (duplicate and often triplicate assays on the fine fraction) were completed using fire assaying with an inductively coupled plasma-optical emission spectrometric (“ICPOES”) finish. Selected samples were also analyzed for copper using sodium peroxide fusion and ICP-OES finish. The different analytical procedures used from 2007 to 2012 are summarized in Table 11-1. If a screen metallic assay was completed, this assay was used in the calculations (Au Final). Gravimetric fire assays had precedence over ICPOES finished assays. No averages were used to compute the Au-Final. Table 11-1

Detour Gold Analytical Methods from 2007 to 2012

January 2007 to July 2007 SGS Code

Description

FAA515

50 g fire assay with AAS finish (5 ppb to 10 ppm)

FAG505

50 g fire assay with gravimetric finish for Au > 10,000 ppm

FAS30K

Gold by Screen Metallics Fire Assay on 500 g screened at 75 µm

August 2007 to June 2008 SGS Code

Description

July 2008 to November 2012 SGS Code

Description

FAI505

50 g fire assay with ICP-AES finish (1 to 10,000 ppb)

FAI525

50 g fire assay with ICP-AES finish (5 to 100,000 ppb)

FAG505

50 g fire with gravimetric finish (for Au > 10 ppm)

FAG505

50 g fire with gravimetric finish (for Au > 10 ppm)

FAS31K

Gold by Screen Metallics Fire Assay on 500 g screened at 106 µm (for Au >5 g/t) – a second pulp is prepared from the reject

FAS31K

Gold by Screen Metallics Fire Assay on 500 g screened at 106 µm (for Au >5 g/t) – a second pulp is prepared from the reject

At the end of the analysis, both the pulps and rejects are kept at the laboratory for a period of three months, after which they are transferred to Detour Gold’s Cochrane facilities. All of the pulps and rejects prior to December 31, 2010 have been discarded.

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11-5

Sample Preparation, Analyses, and Security

11.3.4 Gold Analysis for Block A On Block A, procedures initiated by Trade Winds in 2003 and revised in 2010 were as follow: gold analysis was done on 50 g sample using fire assay with AAS finish (ALS procedure Au-AA24), followed by with gravimetric finish (ALS procedure Au-Grav22) for samples returning over 10 g/t. Total metallic assays for gold were also performed on selected intervals. All sample batches assayed by ALS Minerals included four-acid digestion (“near-total”) standard multi-element ICP packages with Te added (ME-ICP61). ALS Minerals uses industry standards QC assaying procedures for each batch assayed. Coarse rejects were kept at the laboratory in Val d’Or for six months, then returned to Trade Winds for safe keeping. Since the acquisition by Detour Gold, all available pulps and rejects have been transferred to Detour Gold’s Cochrane facilities. In 2011, gold analysis used the standard Actlabs 50 g. fire assay with AA finish procedure (Actlabs code 1A2-50). Samples returning greater than 3 g/t Au were automatically processed using fire assay and gravimetric finish (Actlabs code 1A3-Timmins Au). Total metallic screen assays were also performed on selected intervals, usually when showing visible gold. Trade Winds used a standardized QA/QC procedure although very little information is given, other than the systematic use of blanks, reference material (“RM”), duplicates, and insertion of supplemental blanks after all samples containing visible gold. Coarse rejects were kept at the laboratory in Timmins for six months, then returned to Trade Winds and were kept in a warehouse in Ancaster, Ontario. For the 2012 drilling program on Block A, Detour Gold followed the same procedures as described in Section 11.3.3. 11.3.5 Gold Analysis for Regional Exploration From 2008 to 2013, Detour Gold contracted Accurassay in Thunder Bay for their analytical needs for all regional exploration. Gold analysis was done using fire assaying with atomic absorption spectroscopy (AAS) finish on a 50.2 g sample. Where the gold assays exceeded 3 g/t Au, the fire assay was repeated with a gravimetric finish. All samples with visible gold identified during the field logging procedure went to a metallic screen procedure. All routine assayed samples (AAS) returning values of 5 g/t Au or greater on the first analysis were re-analyzed using the metallic screen procedure. An approximately 1,000 g split was taken after crushing for pulverization. The pulverized sample was sieved through a 150 mesh screen. The >150 mesh portion was repulverized and re-screened, if required, until the mass of this portion of the sample was 5 x dl

Summary of Gold Assays for Drill Core Duplicates N

1,370 1,056

Orig. Core > Dupl. Core

Orig. Core < Dupl. Core

Orig. Core = Dupl. Core

619

603

148

45%

44%

11%

529

504

23

50%

48%

2%

Relative Percent Difference (“RPD”) was calculated (original core assay less duplicate core assay relative to the average). Seven percent (7%) of the duplicate pairs agree within ±5%, 16% within ±10% and 32% within ±20%. There were 39 cases where the differences between drill core duplicates were greater than ±100% and average assays were greater than 0.5 g/t Au. Figure 11-4 Drill Core Duplicates Comparison Chart

There is no bias evident between original and duplicate halves of the drill core. The low percentage of agreement between the two halves of the core is expected based on review of reproducibility for preparation duplicates, the range of gold assays for samples with the same number of visible gold specks and other measurements, i.e. the evidence for the presence of free gold particles. It is therefore assumed that there has been no bias introduced by preferentially submitting the more mineralized half of the core for assay. According to ASL, these variations are typical of core duplicates for gold projects and no changes in procedures are recommended at this time.

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Detour Lake Mine NI 43-101 Technical Report

Screen Metallic Assays Samples were selected on the basis of visible gold and original Fire Assay Au reporting >5 g/t Au and assayed for gold by FA-MET at SGS Minerals. They were then compared with the original gold value by Fire Assay. ASL mentioned the importance to discriminate between samples selected for FA-MET on the basis of visible gold versus the grade of the preliminary 50 gm fire assay. The selection of samples on the basis of the 50 gm fire assay for repeat FA-MET produces a severe selection bias that is exacerbated by preparing a second 500 g pulp from the reject. A total of 66 samples were selected on the basis of visible gold and assayed for gold by FA-MET at SGS Minerals, which were then compared with the original gold value by Fire Assay (Table 11-6). Additionally, a total of 489 samples were selected on the basis of the original fire assay Au reporting > 5 g/t and assayed for gold by FA-MET at SGS Minerals were then compared with the original gold value by Fire Assay (Table 11-7). The subset of samples selected on the basis of original 50 g fire assay determinations agree reasonably well with the FA-MET re-analyses for the current period. For the grade ranges greater than 10 g/t Au, the FA-MET assays are more likely to be higher than the 50 g fire assays for about 60% of the samples tested. In the grade range 5 to 10 g/t Au, which includes 230 samples there are nearly an equal number of cases with FA-MET assays greater than 50 g fire assays, and vice versa. This pattern has been recognized previously and is ascribed to selection bias. There is no evidence that the assays methods are biased relative to one another. Table 11-6

Comparison of Gold by Fire Assay and Screen Metallics (selected on the basis of visible gold)

Criteria

N

all samples

66

>1 g/t Au (SF)

60

1 to 5 g/t Au (SF)

10

5 to 10 g/t Au (SF)

10*

>10 g/t Au (SF)

40

10 to 25 g/t Au (SF)

13

25 g/t Au (SF)

27

Screen Fire > Fire Assay

Screen Fire < Fire Assay

33

33

50%

50%

30

30

50%

50%

6

4

60%

40%

3

7

30%

70%

21

19

53%

48%

7

6

54%

46%

14

13

52%

48%

*Low number of samples significantly impacts comparison. 4 February 2014

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Sample Preparation, Analyses, and Security

Table 11-7

Comparison of Gold by Fire Assay and Screen Metallics (selected on the basis of Original Fire Assay Au > 5 g/t)

Criteria

N

all samples

489

>1 g/t Au (SF)

485

1 to 5 g/t Au (SF)

79*

5 to 10 g/t Au (SF)

230

>10 g/t Au (SF)

176

10 to 25 g/t Au (SF)

134

25 g/t Au (SF)

Screen Fire > Fire Assay

42

Screen Fire < Fire Assay

214

275

44%

56%

213

272

44%

56%

0

79

0%

100%

104

126

45%

55%

109

67

62%

38%

81

53

60%

40%

28

14

67%

33%

*Samples selected for screen metallics are supposed to have fire assay 50 gm assays greater than 5 g/t Au. This group of samples does not qualify and the consistently low screen metallics vs. fire assay is not explained.

Check Assays to Secondary Laboratory Check assays are recommended where the same pulp that was assayed originally is submitted to a different laboratory for the same analytical procedures primarily to augment the assessment of bias based on the RMs and in-house control samples submitted to the original laboratory. RMs are also inserted with samples submitted to the secondary laboratory to measure whether the secondary laboratory is potentially biased. As part of the check assay program, a total of 205 sample pulps (1% of the samples) and 200 drill core samples were submitted to SGS Minerals in Cochrane for check assays (original samples were assayed at SGS Minerals, Don mills) for the period January to December 2012 (Figure 11-5). The average RPD (relative to the mean of the two laboratory results) was 4.84%, indicating that SGS Minerals in Don Mills assays are biased high by 4.84% when compared to the SGS Minerals in Cochrane assays on the suite of samples selected for check assays. It should also be noted that SGS Minerals in Cochrane reported on average 5% low on the RMs included with samples suggesting that the two sets of assays are comparable. SGS Minerals in Cochrane had a series of issues on start-up which appears to have persisted for the check assay program. There were four samples (representing 2% of the samples submitted for check assays) that had assays reported that were different by more than 100%. This is expected based 11-18

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Detour Lake Mine NI 43-101 Technical Report

on comparison of results within the same laboratory and also for free gold-bearing deposits. Figure 11-5 Check Assay on Pulps Comparison Chart

Laboratory Audit by ASL SGS Minerals in Don Mills is a well-recognized ISO-accredited laboratory. The laboratory has been closed in April 2013 and all gold assaying will be done at the SGS Minerals facility in Lakefield, Ontario. ASL’s point of view is that an audit of the new facility is warranted if Detour Gold plans to use SGS Minerals for exploration assays. SGS Minerals in Cochrane was established mid-2012 to support the Detour Lake mine operation. Two visits were made by ASL, in July 2012 and January 2013. With the exception of the check assay program, no drill core has been assayed at SGS Minerals in Cochrane.

11.6 Conclusion It is of SGS Geostat’s opinion that Detour Gold is operating according to an industry standard QA/QC program for the insertion of control samples into the stream of samples for Detour Lake and Block A. The data is of quality sufficient to be used for mineral resource estimation. The following is a summary of the latest audit report by ASL on Block A (Appendix B).

4 February 2014

11-19

Sample Preparation, Analyses, and Security

There is no evidence of systematic gold contamination based on the blanks that were inserted with samples. Blanks were submitted a total of 1,362 times with samples. There was a single quality control failure based on blanks ( 0.25 g/t

51

> 0.25 g/t & 1.0 g/t & 5 g/t

7

Table 12-2

Criteria

Original ≥ Duplicate

Original < Duplicate

Samples within % Relative Difference ± 10%

± 25%

± 50%

> ± 50%

41

25

6

15

31

35

62%

38%

9%

23%

47%

53%

11

4

1

5

9

6

73%

27%

7%

33%

60%

40%

30

21

5

10

22

29

59%

41%

10%

20%

43%

57%

10

7

2

3

5

12

59%

41%

12%

18%

29%

71%

16

11

2

5

13

14

59%

41%

7%

19%

48%

52%

4

3

1

2

4

3

57%

43%

14%

29%

57%

43%

2012 Check Sampling Sign Test Results (Detour Gold)

Average Gold Grade (g/t) Number

Above

Equal

Lower

Results

66

41

0

25

6.4%

Not conclusive

0.08

15

11

0

4

11.8%

Not conclusive

3.04

2.92

51

30

0

21

26.2%

Not conclusive

> 0.25 g/t & 1.0 g/t & 5 g/t

10.71

10.68

7

4

0

3

100.0%

Not conclusive

> 9 g/t

15.09

16.40

3

1

0

2

100.0%

Not conclusive

Original

Check

All Samples

2.37

2.27

< 0.25 g/t

0.10

>= 0.25 g/t

Description

Note: Sorted by average values.

12-8

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Detour Lake Mine NI 43-101 Technical Report

Figure 12-1 Correlation Charts for the 2012 Check Sampling Results (Detour Gold) Detour Gold Check Sample Comparaison

Detour Gold Check Sample Comparaison

30

2 1.5

25

y = 0.7485x - 0.0855 R² = 0.5627

1

Ln Au Check (g/t)

Au Check g/t)

20

15

10

0 -0.5 -1 -1.5

y = 0.0923x + 2.0536 R² = 0.0119

5

0.5

-2 -2.5

0 0

10

20 30 Au Original (g/t)

40

50

-3

-2

-1 0 Ln Au Original (g/t)

1

2

Verification of the Trade Winds Drill Holes SGS Geostat performed different statistical tests including lognormal student T test and sign test on the data from the 2012 independent sampling program on the TWDDH series (127). Original and check Fire Assay results were retained (125) in order to verify the same procedure as well. The sign test and student T tests performed on the fire assay results showed a bias towards the original Trade Winds samples. Table 12-3 shows comparative statistics for the check samples assay results. Table 12-4 shows the 2012 check sampling sign test results on Trade Winds samples. Figure 12-2 shows correlation charts of the check sampling results. Overall, the assay results of the duplicate samples sent to ALS Minerals returned values lower than the original values, with only 48 of the 125 fire assay results being over the original results. The fire assay results show an average correlation (R2=0.8 for log values) with the original assays. The average grade of the Trade Winds sample series is 2.03 g/t Au and SGS Geostat is 1.34 g/t. Sixteen of the 23 duplicate gold values between 1.0 g/t and 5.0 g/t returned values lower than the original samples (based on average grades of duplicate and original values). The sign test performed on all 125 pairs (fire assay results) of values indicates a bias for all values. By sorting according to the original values (fire assay) of Trade Winds samples, there is a bias present for values greater than 9 g/t Au (8 duplicates lower versus 1 higher). The sorting according to duplicates only shows two samples above 9 g/t values. It may be that the choice of high-grade intervals has influenced this result. Looking at the data, SGS Geostat finds that the Trade Winds sample grades (average) are almost always higher than those of the control data. This observation is systematic and significant enough to warrant further investigations at this stage. SGS Geostat finds that there are about as many Trade Winds data points (135,000 assays, 39% of overall data) as Detour Gold (122,000 assays, 35% of overall data) in the database, and the rest comes from prior historical drilling (92,000 assays, 26% overall data). 4 February 2014

12-9

Data Verification

In order to assess the impact of the TW series data on mineral resources, some estimation exercises were done using the same procedures while removing the TW series. Results from this exercise indicate that the mineral resource estimate obtained is very similar at a CoG of 0.5 g/t Au. It is SGS Geostat’s opinion that the Trade Winds database is valid and acceptable for use in mineral resource estimation studies. However, it is recommended that further monitoring be completed to investigate this potential bias on the estimation of mineral resources. At this stage, SGS Geostat recommends an additional sampling campaign on the Trade Winds pulps. Table 12-3

Comparative Statistics for the 2012 Fire Assay Check Sampling Results (Trade Winds)

Criteria (Au)

Count

All Samples

125

< 0.25 g/t

65

> 0.25 g/t

60

> 0.25 g/t & 1.0 g/t & 5 g/t

Original ≥ Duplicate

15

Original < Duplicate

Samples within % Relative Difference ± 10%

± 25%

± 50%

> ± 50%

76

49

18

38

66

59

61%

39%

14%

30%

53%

47%

35

30

12

23

38

27

54%

46%

18%

35%

58%

42%

40

20

6

15

28

32

67%

33%

10%

25%

47%

53%

13

9

1

7

12

10

59%

41%

5%

32%

55%

45%

16

7

2

4

9

14

70%

30%

9%

17%

39%

61%

11

4

3

4

7

8

73%

27%

20%

27%

47%

53%

Note: Sorted by average values.

Table 12-4

Criteria

Check Sampling Sign Test Results (Trade Winds)

Average Gold Grade (g/t) Number Original

Above

Equal

Lower

Results

Description

Check

All Samples

2.03

1.34

125

74

3

48

2.6%

97.45% chance of bias

< 0.25 g/t

0.09

0.09

65

34

3

28

53.9%

Not conclusive

>= 0.25 g/t

4.12

2.70

60

40

0

20

1.3%

98.65% chance of bias

> 0.25 g/t & 1.0 g/t & 5 g/t

11.42

7.34

15

11

0

4

11.8%

Not conclusive

> 9 g/t

22.98

15.63

3

2

0

1

100.0%

Not conclusive

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Detour Lake Mine NI 43-101 Technical Report

Figure 12-2 Correlation Charts for the 2012 Check Sampling Results (Trade Winds) Detour Gold Check Sample Comparaison

Detour Gold TW Check Sample Comparaison

30

2 1.5

25

1 Ln Au Check (g/t)

Au Check (g/t)

20 y = 0.5854x + 0.1564 R² = 0.8083 15

10

y = 0.8422x - 0.1853 R² = 0.8311

0.5 0 -0.5 -1 -1.5

5 -2

0

-2.5

0

10

20 30 Au Original (g/t)

40

50

-3

-2

-1 0 Ln Au Original (g/t)

1

2

12.7 Final Drill Hole Database Detour Gold provided the final database for Detour Lake and Block A. The final drill hole database is between sections 12,000E and 20,700E, and between 19,540N and 20,800N and covers the entire mine operations (open pit) and Block A deposit. It includes a total of 7,107 drill holes of which 1,395 holes were drilled by Detour Gold. The database contains all assays received from the analytical laboratory by the cut-off date of June 7, 2013. Table 12-5 lists all drilling data included in the final drill hole database (Detour Lake and Block A areas). Twin holes drilled by SGS Geostat (DGG-09 series) and grade control holes drilled in 2010 by Detour Gold were not considered in the resource estimation process. The database covers an area that was retained for the mineral resource estimation update of Detour Lake and Block A. Exploration drilling to the south of the Property and all other drilling information outside the database boundary mentioned above were not verified or validated by SGS Geostat. It is SGS Geostat opinion that the drilling information included in the final drill hole database (Detour Lake and Block A) as of June 7, 2013 is valid and acceptable for use in mineral resource estimation studies.

4 February 2014

12-11

Data Verification

Table 12-5 Period

Detour Lake Drilling Data Included in the Final Resource Estimation Drill Hole Database Operator

Historic

1974 to 1979

1979 to 1987

Drill Hole Series

Location

Number of Holes

Metres Drilled

Number of Survey Records

Number of Lithology Records

Number of Assay Records

Assayed meters

% Assayed Metres

G-

Surface

1

170

-

3

2

1

1%

439-

Surface

18

14,184

288

1,408

8,126

7,561

53%

499-

Surface

3

804

15

47

349

342

43%

36, 38, 38W

Surface

130

38,822

675

2,278

16,845

26,612

69%

38U

Underground

176

11,524

317

1,124

7,468

11,323

98%

CRL

Surface

189

18,638

251

1,625

11,484

17,189

92%

100, 120, 206

Underground

213

11,712

233

919

8,518

11,693

100%

00-

Surface

164

24,594

442

3,676

17,492

17,472

71%

03 to 15

Underground

3860

439,248

8,639

70,903

391,628

387,509

88%

56L to 66L

Underground

317

6,516

317

1,173

6,516

6,514

100%

464/R464

Surface

129

66,127

1,481

4,608

39,547

38,988

59%

DPH

Underground

2

603

19

41

521

545

90%

PM

Surface

103

25,352

1,189

4,151

17,923

16,793

66%

DG-07

Surface

306

113,520

33,063

7,532

108,377

106,217

94%

DG-08

Surface

316

119,987

35,314

6,518

114,688

112,525

94%

DG-09

Surface

241

103,251

27,269

4,754

95,865

94,290

91%

DG-10

Surface

203

109,561

3,028

4,429

107,511

100,992

92%

DG-11

Surface

188

88,238

2,380

3,305

86,849

80,916

92%

DG-12

Surface

8

4,789

138

155

4,893

4,666

97%

DBKA-12

Surface

132

44,626

1,264

1,693

44,746

41,008

92%

Amoco

Campbell

Detour Mine Group 1987 to 1998 PDX 2004 to 2006

2007 to 2012

Pelangio

DGC

DGE

Surface

1

826

18

46

828

803

97%

TWDDH

Surface

407

168,788

39,368

16,179

134,514

129,073

76%

Total Surface

2,539

942,277

146,183

62,407

810,039

795,447

84%

Total Underground

4,568

469,603

9,525

74,160

414,651

417,584

89%

Total All

7,107

1,411,881

155,708

136,567

1,224,690

1,213,031

86%

2003 to 2011

12-12

Trade Winds

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Detour Lake Mine NI 43-101 Technical Report

12.8 Summary and Recommendations SGS Geostat completed an independent analytical check program on selected 2012 drill holes from Detour Gold and holes drilled by Trade Winds. A total of 193 quarter-core samples selected from drill holes DG11 (30) and DBKA (36) as well the Trade Winds drill holes series TWDDH (127) were analyzed. The results of the duplicate samples generally show an average correlation with the original assays for the Detour Gold DG11 and DBKA series. Based on statistical test performed, SGS Geostat cannot confirm the presence of any bias for the Detour Gold series. The results of the check sampling program outline the significant variability of the high gold values due to the nugget effect observed at Detour Lake and highlight the necessity of capping the high gold values for the mineral resource estimation process. The observation of Trade Winds check sampling by SGS Geostat outlined a systematic and significant difference in average values for ranges below 0.25 g/t Au and for ranges over 5 g/t Au. These observations are significant enough to warrant further investigations at this stage. SGS Geostat also found that there are about as many assay results of Trade Winds (135,000 assays) as Detour Gold (122,000 assays) in the Block A database and about 26% of the data comes from prior historical drilling programs (92,000 assays). The results of the check sampling program outlined the significant variability of the high gold values due to the nugget effect observed at Block A and highlight the necessity of capping the high gold values for the mineral resource estimation process. In 2012-2013, SGS Geostat verified the Trade Wind and Detour Gold certificates of analyses results with the database. No major discrepancies were found. SGS Geostat did not conduct any verification of the historical (before Trade Winds) drill hole data as part of the current data verification program. However, Trade Winds conducted a limited historical re-assay program and Detour Gold has followed up on Trade Winds’ database observations in WGM (2011). In the pre-feasibility study of the Detour Lake mine (Met-Chem, 2009), Scott Wilson RPA made a number of recommendations as part of their data verification program. Detour Gold has carried out a number of those recommendations, while addressing other recommendations according to impact on production. SGS Geostat did not conduct any verification of the underground infrastructures and void models as part of the current data verification program. However, Detour Gold has followed up on Scott Wilson RPA recommendations with the validation and completion of the stopes model based on the breakthrough information from the ongoing drilling program and existing historical data available to Detour Gold. Additional verification of the void models is also in progress with the review of historical stopes survey data. As part of the feasibility study of the Detour Lake mine, SGS Geostat conducted different verification programs aimed at the validation of the historical analytical data and the analysis of the nugget effect observed in the Detour Lake deposit. The conclusions of SGS Geostat verification programs are summarized as follows:

4 February 2014

12-13

Data Verification

The comparison of the mean gold grade in the same resource block between the Detour Gold analytical data and the historical analytical data within the different mineralized domain shows a mean grade systematically higher for the historical analytical data compared to Detour Gold analytical data. Comparative analytical results of independent check assays selected on historical core highlighted a potential positive bias for the historical assays from hole CRL-039. Although a high variability is expected for this kind of comparative study due to the high nugget effect observed in the Detour Lake deposit, the assays variability for hole CRL-039 is significantly higher than the average variability outlined by Detour Gold’s QA/QC results for half core duplicates. The twin drilling campaign conducted as part of the independent verification program shows a fair to good correlation between the historical and Detour Gold assay data versus the assay data collected from the twin drill holes. From the total of five holes completed for this test, hole CRL-030 was the only hole showing poor correlation with the original data. In order to quantify the effect of a potential analytical bias toward some of the historical drill assays, SGS Geostat conducted a resource estimation exercise on the mineralized Domain 2 with the objective of quantifying the effect of the CRL series assays on the overall gold content of the mineralized domain. Based on these results, SGS Geostat considers the effect of removing the historical CRL series drill holes to be insignificant compare to overall gold content in the deposit. Although there might be a potential analytical bias with the drilling data of the CRL series, SGS Geostat is of the opinion that the effect of the potential bias is not significant. Based on the results of the different verification programs suggesting a potential bias toward some historical analytical data, SGS Geostat recommends conducting additional verification of the historical analytical data with an emphasis on the analytical data pertaining to the Campbell drilling series. Following the results obtained from the first total gold analysis test completed by SGS Geostat, Detour Gold initiated five additional tests targeting different types of mineralization across the Detour Lake deposit, and analytical results from those test blocks were received from SGS Minerals. SGS Geostat has not yet reviewed the SGS Minerals report. However, based on the analytical results received from SGS Minerals, Detour Gold has concluded that overall, the results of the test blocks demonstrated that the original fire assays used by Detour Gold are a good approximation of the total gold content calculated from the gravity and cyanidation test work. Only one of the tests indicated a discrepancy between the head grade and the capped assay values. Detour Gold does not intend to do any further testing at this stage of the mine development. Detour gold acknowledged that throughout the reviews various recommendations have been made. Follow up work was carried out to address some of the recommendations while others have limited impact on the current operation. Some recommendations are still pending and will be evaluated on a necessity basis. Any recommendations that would have had significant impact on the operation have been considered.

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Detour Lake Mine NI 43-101 Technical Report

As part of the independent verification program, SGS Geostat conducted data verification of historical records and compared them to the data from the Detour Gold master database. The validation of the Detour Gold master database highlighted a large amount of values and data population at 0.1 g/t Au, potentially resulting from rounding of numbers during transcription. Due to the high number of these values observed during this verification program, SGS Geostat recommends to conduct additional verification of historical records and to locate the original assay certificates if possible. In assembling the database for the mineral resource estimate, SGS Geostat corrected the sample records containing errors. SGS Geostat is of the opinion that the final drill hole databases are adequate to support a mineral resource estimate.

4 February 2014

12-15

Detour Lake Mine NI 43-101 Technical Report

13.0 Mineral Processing and Metallurgical Testing The mineral processing requirements and supporting metallurgical testing for the Detour Lake mine were based on the results from the feasibility study. The selected process was validated in the first year of operation of the processing plant. The metallurgical test work completed for the feasibility study and subsequent test work are described in details in BBA (2010, 2011, and 2012). The section below summarizes the results of this test work. Preliminary test work completed for the Block A deposit is summarized in section 13.13. Refer to section 17.2 to 17.4 for an update on the process plant results following the first year of operation at the Detour Lake mine.

13.1 Sample Selection and Preparation The sample selection approach used for metallurgical testing to support the plant design criteria provided a sufficiently large number of metallurgical test composites of varying gold grade and varying rock type and mineralization. All samples selected were from diamond drill holes (DDH) for which assays were available as of August 2009. Assay rejects (typically -¼ inch) were used in the selection process to prepare the composites by rock type.

13.2 Comminution Test Work Comminution test work was conducted between 2007 (Phase 1) and 2009 (Phase 2). In addition to sample selection and preparation for metallurgical testing, HQ drill bit sizing was drilled to provide whole core samples of the eight identified rock types for comminution testing. Eighty-three (83) samples representing the major lithologies of the Detour Lake deposit were provided from Phase 1 and an additional forty-nine (49) from Phase 2. Test work by BBA included the determination of the specific gravity (SG), the overall hardness (using SMC Test® A x b), the crushing work index (CWI), the bond rod millwork index (RWI), the bond ball mill work index (BWI) and the abrasion index (Ai). Table 13-1 presents the results of the whole set of data for Phases 1 and 2.

4 February 2014

13-1

Mineral Processing and Metallurgical Testing

Table 13-1

Comminution Test Statistics SG (g/cm3)

Statistic

SMC Test®

CWI

RWI

BWI @150M

Ai g

Wax

Pyc

SMC

Axb

kWh/t

kWh/t

kWh/t

Average

2.89

2.89

2.92

26.0

14.2

18.0

14.3

0.421

Minimum

2.49

2.67

2.72

53.1

5.2

12.0

9.1

0.08

10th Percentile

2.74

2.81

2.80

30.2

9.9

15.9

11.2

0.238

25th Percentile

2.82

2.84

2.88

27.5

11.9

17.2

12.7

0.365

Median

2.90

2.90

2.94

25.7

14.8

18.0

14.3

0.484

75th Percentile

2.98

2.93

2.98

24.3

16.9

18.9

15.5

0.54

90th Percentile

3.01

2.98

3.01

23.4

19.7

19.9

16.5

0.544

Maximum

3.19

3.09

3.10

22.5

25.6

22.7

20.1

0.548

13.2.1 Circuit Simulation The grindability results from the comminution testing were used to conduct JKSimMet simulations of different SAG mill circuit configurations and operational variables (circulating load, P80, etc.). A total of four (4) series of simulations were conducted: series A and B consisted of a dual grinding line circuit, series C was a single line circuit, and series D was the optimization of series B. BBA selected a SABC (SAG-Ball-Crushing) grinding circuit configuration for Detour Lake. Note that the feed to the SAG mill is subjected to primary and secondary crushing to reduce the feed size to the SAG mill. As third party reviewers, Ausenco and SAG Design were requested to provide an opinion and review the grinding circuit design basis. Table 13-2 shows that the total power (@ pinion) estimated in simulation BBA/SGS-JK has a good fit with the power estimated by Ausenco (Braun, 2009) for grinding circuit sizing. On the other hand, SAG Design (Starkey, 2009) estimated the highest total power. The SAG and ball mills selected by SAG Design were the same as selected in JKSimMet simulations. It was recognized that there will be periods of operation when the pre-crusher will not be available and the SAG mill circuit will operate without pre-crushing. JKSimMet simulations predicted that there is a potential 33% loss (accounted for in the 55,000 tpd nameplate capacity) in the periods where the pre-crusher is not operating. The study process design criteria were based on simulation D12 using the 75th percentile of the grindability results. Basis for Process Criteria Analysis of the simulation results provided the basis for the process criteria of the grinding circuit equipment (Table 13-2). The main characteristics can be found in Table 13-3.

13-2

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Detour Lake Mine NI 43-101 Technical Report

Table 13-2

Process Design Basis

Reference Item

Units

Criteria Average

Criteria Design

General operation data Total operating utilization

%

Grinding circuit type Throughput rate with pre-crushing

92

92

SABC + pre-crushing

SABC + pre-crushing

1,245

1,285

1

1

t/h

Pre-crusher (# of units) Pre-crusher motor power

HP

1,000

1,000

Product size - passing (P80)

mm

60

60

1 – 36’ x 17.25’

1 – 36’ x 17.25’

µm

1,700

1,700

%

28

35

kWh/t

9.9

9.9

1

1

SAG Mill (# of units - dimension) Transfer size - passing (T80) Pebble recirculating load Estimated power consumption (motor input) Pebble Crusher (# of units) Pebble-crusher motor power

HP

1,000

1,000

Average crusher product size (P80)

mm

13

13

1 – 25’ x 38.5’

1 – 25’ x 38.5’

µm

95

95

%

250

250

kWh/t

10.6

10.6

Ball Mill (# of units - dimension) Product size - passing (P80) Proportion circulating load in Ball Mills Estimated power consumption (motor input)

Table 13-3

Comparisons Between Different Methodologies for Power (@ pinion) and Mill Sizing Calculation for a SABC Circuit t/h

Mill Size (SAG)

BBA/SGSJK simulations

2,132

36' X 17.25’

11.06

25’ X 38.5’

13.05

24.11

Ausenco

2,038

36’X 22’

13.3

26’ X 38’

12.2

25.5

SAG Design

2,038

36' X 17.25'

11.75

25' X 38.5'

15.34

27.09

Description

SAG kWh/t (@ pinion)

Mill Size Ball

Ball Mills kWh/t kWh/t Total (@ pinion) (@ pinion)

13.3 Metallurgical Test Work The pre-feasibility study metallurgical test program was conducted on eight overall composites and included the following: mineralogical examination; gravity recovery tests including gravity recoverable gold (“GRG”) tests; cyanide leach tests on gravity tailings; grade variability testing; barren solution recycle testing; cyanide destruction tests; preparation of tailings for chemical and physical characterization and environmental testing; and environmental test work. 4 February 2014

13-3

Mineral Processing and Metallurgical Testing

The pre-feasibility study test work was conducted with composites representative of the Detour Lake deposit. The composites were prepared as follows: 

Composite 1: Blend of Major (MF, KMF, PF, KPF), and minor (CH, TC, CBPF, CG) rock types;



Composite 2: Blend of MF and KMF rock types;



Composite 3: Blend of PF and KPF rock types;



Composite 4: Blend of Major rock types; and



Composite 5, 6 and 7: Blend of Major and Minor (TC and CG) rock types.

Confirmation test work was conducted in 2009 by BBA. The different lithologies present in the orebody were used to prepare a master composite representative of the mill ore feed. The target average feed grade at the time of test work for the master composite was 1.15 g/t Au. Approximately 980 kg of drill core was sent to SGS Lakefield to prepare the master composite. Gravity Circuit The pre-feasibility study gravity gold recovery testing showed that the average recovery for the weighted rock blend representing 96.4% of the Detour Lake deposit was calculated at 45.4% for a calculated head grade of 1.51 g/t Au. The nugget effect observed in the Detour Lake mineralization, and the results of the gravity recovery tests did confirm that gravity recovery is a key component of the milling process at Detour Lake. From the 2009 confirmation test work by BBA, the results of the GRG test work were compared to the previous results. The test data of the confirmation test work (Knelson Fullam M., March 2010) was forwarded to Knelson Research & Technology Centre for modeling and interpretation of gravity recovery circuits. When analyzing all the gravity results, regardless of head grade, it was found that recoveries vary from 30% to 45% (between the 25th and 75th percentile), essentially in agreement with the metallurgical test results. Furthermore, it was found that the GRG number (53.9%) from the 2009 confirmation test work was in the lower range of the GRG results (from 51.9% to 71.2%) previously presented. The latter could be explained by the higher gold head grade blend used in the previous test work. Cyanidation The pre-feasibility study cyanide test work on gravity tails was conducted to generate process design criteria and optimal conditions for gold extraction. The optimization test work included: grinding size (P80) versus gold recovery, leach time, and reagent consumption (lead nitrate). A rock blend composite of Major/Minor rock types, Composite 1, was used for grind-leach extraction related test work. Duplicate leach tests on gravity tails using target grinds (P80) of 69, 77, 82, 90 and 102 µm were performed. The test work conditions included 0.1 kg/t 13-4

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Detour Lake Mine NI 43-101 Technical Report

lead nitrate addition and cyanide levels of 0.5 g NaCN/l. The leach time was estimated to be 48 hours with sampling of solution at 8, 24, 32 and 48 hours. The gravity gold recovery result for this composite at a grind P80 of 146 µm was approximately 25.3%. BBA conducted cyanidation tests to validate process design variables such as leaching time, feed particle size and lead nitrate addition. A statistical analysis of the previous test results was conducted to estimate the minimum number of repeats that would be required. It was determined that two sets of tests with 20 repeats each were required to distinguish a difference of one percent (1%) of gold recovery. Analyses of the cyanidation results are shown in Figure 13-1. Observations made were: 

No improvement in gold recovery by the addition of lead nitrate. In conclusion, lead nitrate is not required for Detour Lake;



Each set of data shows different dispersion, but average gold tail grades are in the same order;



At 75 µm, it was found that the tails are similar for 24 hours and 48 hours. This indicates that the leaching time at 75 µm is sufficient at 24 hours; and



At 105 µm, there is a 1.2% gain in gold recovery between 24 hours and 48 hours.

4 February 2014

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Mineral Processing and Metallurgical Testing

Figure 13-1 Box and Wihiskers Plots for the Confirmation Test Work

Notes to read box and whiskers plot:

13-6



Box: represents 25 to 75 percentile. Inside line represents 50 percentile (median);



Whiskers 10 to 90 percentile;



Dots: Min and Max values; and



“+” represents the average.

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Grinding Size and Leach Time Results from the duplicate bottle leach test were used to study the relation between the leach time and recovery. The analysis was performed on gold tails due to the high variability of the pre-feasibility study results and accuracy of the tails assays. Figure 13-2 shows the relationship between gold in tails versus the leach feed grind at different leach times. It was observed that: 

The gold tail shows similar results at 24 and 32 hours, but at 48 hours shows lower grade (i.e. higher recovery);



Around 110 µm, an inflexion in the recovery versus grind relationship occurs; and



A comparison between the curves at 24-32 hours with 48 hours indicates that the difference in gold losses is in the range of 0.02 g/t Au and is fairly constant along the particle size studied (from 70 to 110 µm). If an average head of 1.37 g/t Au is assumed (the average head grade at the time of the test work), the loss in recovery is in the order of 1.8% between leaching at 24 and 48 hours.

Figure 13-2 Gold in Tails (g/t) vs. P80

4 February 2014

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Mineral Processing and Metallurgical Testing

Copper Dissolution The Detour Lake deposit contains small concentrations of copper varying from 0.025% copper to 0.08% copper with copper dissolution in leach varying from 5% to 15%. Metallurgical test results showed that these extraction rates provided leach solution grades normally varying from 20 to 60 mg3/l in copper content (there were outliers in the 80 to 280 mg3/l in grade variation tests when gold grades varied from 2.0 g/t to 9.0 g/t Au). Oxygen versus Air Test Work A series of individual kinetic tests were conducted to compare the gold leaching performance with oxygen versus air. Figure 13-3 shows the kinetic results of individual leaching tests using oxygen versus air and also shows that: 

It is possible to reduce leaching retention time (remove leach tanks) and keep the same gold recovery by using oxygen instead of air; and



When tonnage would be increased from 55,000 to 61,000 tpd, leaching retention time would be reduced from 29 to 26.5 hours, resulting in a residual tails increase within 0.01 g/t Au. However, the plan would be to add leach tanks (1 per row) and bring leach time to 31 hours thereby causing no effect on the residual tailings grades.

Figure 13-3 Oxygen versus Air – Gold Leaching Kinetic Comparison

13.4 Recovery Estimates Potential improvements with the former models for gold recovery were identified early during the feasibility study. The former models were adjusted to the latest process design criteria (leaching 29 hours and P80=95 µm) and block model (August 2009). BBA reviewed and presented a new tail-based model representative of the new process design criteria that included plant losses. 13-8

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Detour Lake Mine NI 43-101 Technical Report

Recovery Model Raw data was used to determine the overall gold recovery versus gold head grade relationship. The results are presented in Figure 13-4 and Table 13-4, showing the relationship between gold in tails versus gold feed. Model for Gold Tail versus Gold Head Grade An overall tail model was developed from a weighted average of the three major lithologies. Table 13-4 shows the overall tail model. The overall recovery can be estimated from the following equation: Overall recovery = (1-tail/head grade) x 100% plant losses - normalization factor. Figure 13-4 Tail Au versus Head Grade to Gravity

Table 13-4

Tail versus Gold Head Grade (BBA Tail Model)

Lithology

BBA Equation

R2

MF

Tail = 0.0445 (Au) + 0.0271

0.4231

Over a range of 0.4 to 1.6 g/t Au

Figure 13-4

PF

Tail = 0.0644 (Au) + 0.0009

0.8814

Over a range of 0.4 to 1.6 g/t Au

Figure 13-4

KPF

Tail = 0.0592 (Au) + 0.0362

0.6956

Over a range of 0.4 to 1.6 g/t Au

Figure 13-4

Overall

Tail = 0.054 (Au) + 0.019

Range

N.A.

Reference

Derived equation-based on weight averages

Note: Au represents head grade. The leaching test work was conducted at an average P80 µm. Leaching time = 48 hours.

4 February 2014

13-9

Mineral Processing and Metallurgical Testing

Recovery Model The updated equations used in the pre-feasibility study and feasibility study block models and mining plans are presented in Table 13-5. Table 13-5

Lithology

Updated Equation Used in the Pre-Feasibility Study and Feasibility Study Block Models and Mining Plans Model Equation

R2

Range

MF

Recovery = 1.6289LN(Au)+92.5330.98-0.46

0.4922

Over a range of 0 to 30 g/t Au

PF

Recovery = 0.6458LN(Au)+93.4820.98-0.46

0.1523

Over a range of 0 to 10 g/t Au

KPF

Recovery = 2.546LN(Au)+89.9320.98-0.46

0.8444

Over a range of 0 to 30 g/t

Overall

Recovery = 1.8687LN(Au)+92.5780.98-0.46

N.A.

Note: Refer to feasibility study (BBA, 2010).

Observations regarding Table 13-5 include:

13-10



The equations were adjusted by including gold losses (bold numbers in Table 13-5);



Pre-feasibility study models were developed for a nominal P80 of 75 µm (average 80 µm) and 48 hours leaching for gold head grades from 0 to 30 g/t; and



Plant gold losses were estimated as 0.46% Au and gold losses due to reduction of leaching time from 48 to 29 hours were estimated as 0.98%.

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

13.5 Estimated Recovery for the Life of Mine As discussed above, BBA mining group used the models presented in Table 13-5 during the pre-feasibility study and feasibility study in order to estimate the overall gold recovery over the LOM. It can be observed in Table 13-6 that a good agreement exists between BBA’s tail model and the feasibility study model where a small positive increment in recovery for the BBA new model (0.19%) can be observed. However, to be conservative, the LOM recovery estimated by using the feasibility study models should not be changed based on the average gold head grade over the LOM where the recoveries calculated from both models differ less than 0.19%. The equations used in the block model remain valid. The BBA process group reviewed the models in order to confirm the overall gold recovery results predicted by the previous models. The data was normalized to P80 = 95 µm, and the leaching time was corrected to 29 hours. The former and newly estimated recoveries are presented in Table 13-6. The total gold losses were estimated by BBA as 0.18% (based on solution losses) + 0.1% (based on fine carbon) = 0.28 % Au. Historically, losses of 0.5 to 0.6 % are reported for 1986-1987 (Kresin, 2007). Kemix®’s pump cell CIP system with less carbon handling and consequently less carbon attrition justifies the estimated reduction in carbon losses. Table 13-6

Comparison Between BBA (Tail Model) and Previous Model Head grade Au g/t

Recovery (%) using equation in block model (Pre-Feasibility Study and Feasibility Study)

Pre-Prod Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 Year 11 Year 12 Year 13 Year 14 Year 15 Year 16

1.09 1.14 1.23 1.21 0.97 0.90 0.97 1.00 0.91 0.85 0.89 0.95 1.05 1.11 1.15 1.24 1.33

91.6 91.4 91.5 91.5 90.8 91.0 91.0 91.1 91.0 91.0 91.0 91.2 91.3 91.2 91.3 91.4 91.5

91.5 91.6 91.7 91.7 91.3 91.1 91.3 91.3 91.1 91.0 91.1 91.2 91.4 91.5 91.6 91.7 91.8

-0.09 0.18 0.23 0.22 0.49 0.15 0.22 0.21 0.15 0.06 0.03 0.05 0.17 0.31 0.33 0.33 0.30

Average

1.06

91.2

91.4

0.19

Year

4 February 2014

Recovery (%) using BBA Tails Model

Difference (%)

13-11

Mineral Processing and Metallurgical Testing

13.6 Update of Recovery Model The gold recovery achieved at the process plant from October to December 2013 is compared to what was predicted by the gold recovery model used in the block model (prefeasibility study and feasibility study) (Figure 13-5). For gold head grades above 0.75 g/t, the actual gold recovery achieved during this period was higher than the gold recovery model. During this period, the plant operated between 9,000 and 63,700 tpd and the P80 varied from approximately 70 to 95 µm and there did not appear to be a correlation between gold recovery and P80. Figure 13-5 shows that when comparing plant data to the predicted recovery model, there is a stronger correlation between gold head grade and gold recovery. Figure 13-5 Comparison of Actual Recovery Data to Predicted Recovery

In the current mine plan, the average yearly gold head grade varies between 0.83 and 1.25 g/t over the LOM, with an average of 1.02 g/t. Figure 13-5 indicates that the gold recovery achieved from October to December 2013 (first quarter where gravity recovery was available at acceptable availability) was 1% to 3% higher than what was predicted by the pre-feasibility and feasibility studies model. Based on this actual data, an increase of 1% gold recovery over the prediction of the gold recovery model was incorporated into the LOM plan.

13-12

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Detour Lake Mine NI 43-101 Technical Report

13.7 Comparison CIP versus CIL Test work was conducted to compare the performance of a carbon-in-leach (CIL) system versus a carbon-in-pulp (CIP) system. The analysis of the results led to the selection of the CIP process.

13.8 Modeling Carbon-in-Pulp (CIP) Modeling of a conventional CIP plant was conducted during the pre-feasibility study. The actual CIP system recommended by BBA for the Detour Lake was the Kemix® pump cell. Further analysis of the modeling indicated that the mass transfer coefficient was penalized due to the intensity of agitation of the laboratory unit (180 W/m3) versus the industrial scale CIP tank (30 W/m3). It was found that the level of agitation of an industrial pump cell is 330 W of 50-60 W/m3 (Kemix®). Therefore, the mass transfer coefficient should be higher. It was recommended to repeat the modeling using a configuration that was similar to a carrousel system (pump cell). Kemix® historical data from similar operations indicated that higher carbon gold loadings and lower carbon attrition can be achieved.

13.9 Thickening and Rheology A settling test work program was conducted for confirmation of thickener sizing and flocculent consumption. The samples for settling tests (130 kg) were collected from the master composite. Samples were ground to 75 and 105 µm and were sent to a number of thickener supplier’s laboratories: Delkor, Outotec, Westec and FLSmidth. Flocculent screening was conducted prior settling test work. SNF 905 VHM flocculent gave the best performance (Outotec and FLSmidth) and the estimated consumption was 25 g/t and 18 g/t for 75 and 105 µm, respectively. The four suppliers gave similar settling test results, with thickeners in the range of 52 to 58 metres in diameter. Thickeners of a 55-metre diameter were selected, and a flocculent dosage of 18 g/t per thickener was used for design.

13.10 Cyanide Destruction Laboratory test work was conducted at SGS Lakefield to investigate the detoxification of cyanide slurries (cyanide destruction) from leaching samples for Detour Lake. For this cyanide destruction test work, SO2/air method was the selected process. Test work was performed in four (4) different phases and under two detoxification conditions, either in a batch process or in a continuous process. Phase 1 was carried out on a batch basis on Composite 1 to 4. Phases 2 to 4 were carried out using a continuous cyanide destruction process on Composite 4, 5, and 7. Extensive detoxification test work conducted on slurry from leaching of Composites 5 and 7 indicates that it was generally possible to achieve a residual cyanide level below 1 ppm in the laboratory in a single-stage one-hour retention time process. The reagent requirements per grams of CNWAD (cyanide, weak acid dissociable) in the feed, for treating a slurry at 50% w/w density, were 3.5 to 4.2 g equivalent SO2 (added as sodium 4 February 2014

13-13

Mineral Processing and Metallurgical Testing

metabisulphate), 2 to 2.5 g hydrated lime and 0.11 g copper (added as copper sulphate pentahydrate). The detoxification results were transmitted to Cyanco (Cyanco - Steir, 2009), who provided an independent review of the results, and reported the following treatment criteria: 

CNT (discharge): < 5 ppm;



SO2 dosage: 5 g/g CNWAD of liquid SO2;



Copper dosage: 0.14 g/g CNWAD;



Lime dosage (CaO): 2.5 g/g CNWAD (when using sodium metabisulphate); 4.8 g/g CNWAD (when using liquid SO2);



Retention time: 1.5 hours; and



Reactors: 2 x 1,900 m3.

13.11 Reagents Metallurgical testing confirmed that gravity gold recovery, cyanide leach extraction, and CIP gold recovery; followed by cyanide destruction would be the process of choice for Detour Lake. Reagent use associated with cyanidation (sodium cyanide, lime and lead nitrate) and cyanide destruction (SO2 equivalent, lime and copper) was recorded in all testing. A summary from the complete dataset of reagent consumption including flocculent, sodium cyanide (total cyanide without recycle) and lime for the proposed recovery circuit is presented in Table 13-7. Also included is an estimation of reagent consumption including sulphur dioxide, lime and copper (to be added as copper sulphate) for the cyanide destruction circuit.

13-14

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Detour Lake Mine NI 43-101 Technical Report

Table 13-7

Reagent Consumption Summary (Thickening, Cyanidation, and Cyanide Destruction) Thickeners Reagent

Pre-leach (g/t)

Flocculent (SNF 905 VHM)

18 (range 7 to 25)

Pre detox (g/t) 18 (range 7 to 20)

Cyanidation Reagent

Mean (kg/t)

Range (kg/t)

Cyanide (NaCN)

0.33

0.04 to 2.65

Lime (CaO)

0.48

0.23 to 1.27

Cyanide Destruction Reagent

Mean (g/g CNWAD)1

Range (g/g CNWAD) 1, 2

Sulphur Dioxide (SO2)

5.0

3.5 to 4.2

Lime (CaO)

4.8

2.0 to 2.5

0.14

-

++

Copper (Cu ) 1

Based on Cyanco recommendation.

2

Based on SGS Lakefield test work - Project 11743-002.

13.12 Selected Process Both the mineralogy and gravity gold recovery testing indicated a significantly high component of liberated gold that was very amenable for recovery by gravity concentration, generally yielding gold recoveries in the 30% to 45% range depending on head grade. The nugget effect observed in the Detour Lake mineralization and the results of the gravity recovery tests confirmed that gravity recovery would be a key component of the milling process. Cyanidation tests on gravity tailings included testing of the grind-recovery relationship, the use of oxygen for leaching, and the carbon in leach CIL to optimize leach conditions. Based on the assessment of test results, cyanidation testing of gravity tailings confirmed that the leach extraction circuit for Detour Lake, following gravity gold recovery, would consist of direct whole-ore leaching to achieve maximum gold recovery. Optimized leach conditions identified included a grind (P80) of 95 µm, leaching with 0.5 g NaCN/l cyanide solution strength and 29 hours leach retention time for an estimated average gold head grade of 1.06 g/t Au and overall gold extraction of 91.2% over the LOM. A CIP (pump cell) is the choice for gold absorption onto carbon. Cyanide destruction uses a SO2 based circuit with two reactor tanks and a 1.5 hours retention time with a design discharge at 5 ppm cyanide total.

4 February 2014

13-15

Mineral Processing and Metallurgical Testing

13.13 Metallurgical Testing on Block A 13.13.1

2010 Metallurgical Test Work

Over a four-month period ending October 2010, Trade Winds, the operator of the joint venture, completed a preliminary metallurgical test program on three composites of drill core from the Block A deposit. The details of the program are reported in WGM (2011). The test program included: 

Sample preparation: crushing, blending and splitting, to provide three composites from approximately 150 kg of drill core;



Head analysis: triplicate screened metallics measurement, with singleton subsamples submitted for multi-element ICP scan;



Comminution test work: a single standard Bond ball mill grindability test to be conducted on each composite;



Core bulk density determination: 10 pieces of drill core selected at random for standard water submergence bulk density determination. Paraffin wax coating as required;



Gravity separation test work: a single 10-kg test on each composite, using a 3 inch Knelson concentrator and Mozley table for gravity concentrate production at a nominal 150 μm grind;



Cyanidation test work: a battery of standard bottle roll cyanidation tests on both gravity tailings and whole ore for each composite. Tests to determine the sensitivity to grind size and cyanide concentration for each composite.

Samples were selected from a single drill hole (TWDDH253). This hole was selected as it intersects three significant mineralized zones and therefore provides a good preliminary representation of likely mill feed mineralization styles: 

Composite 1 consisted of 47.0 kg of core. Using measured masses and interval assays, the composite grade was estimated at close to 2.7 g/t Au;



Composite 2 consisted of 28.9 kg of core. Using measured masses and interval assays, the composite grade was estimated at close to 0.78 g/t Au; and



Composite 3 consisted of 40.4 kg of core. Using measured masses and interval assays, the composite grade was estimated at close to 2.6 g/t Au.

Head Analysis Grade analysis showed high variability, which is consistent with coarse gold and nugget effect. No problematic concentrations of deleterious elements were noted in any of the composites. Silver grades were low in each composite (below the AA detection limit of 0.5 g/t).

13-16

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Detour Lake Mine NI 43-101 Technical Report

Bulk Densities Bulk densities were measured for 10 random pieces of solid drill core for each composite prior to crushing. Average bulk density for the composites ranged from 2.95 to 3.02 g/cm3. Grindability Sub-samples of each composite were submitted for Bond ball mill work index determination to provide an initial indication of grindability. Work index data (150 μm closing size) ranged from 9.0 to 10.2 kWh/t. Gravity Separation A 10-kg charge was prepared for gravity concentration testing of each composite. Charges were ground to a target of 80% passing 100 μm prior to upgrading, first with a lab scale Knelson concentrator, and then with Mozley table as a cleaner. Gravity recovery ranged from 20.1% to 80.4% for the samples tested. This variability was taken to be consistent with the nature of free gold in some samples and complex or disseminated gold in other samples. Cyanidation The tailings produced in the gravity tests described above were blended and split to give replicate 1-kg charges for cyanidation work. The cyanidation scoping tests tested sensitivity to grind size and NaCN (sodium cyanide) concentration. All leaches were completed at 40% solids, 10.5 to 11.0 pH, and 48 hours of leaching. Solution subsamples were taken at 8, 24 and 32 hours to help determine leach kinetics. Using 0.5 g/l NaCN, gravity + cyanidation recovery was measured to vary between 88.3% and 98.7%. Recovery was found to increase with finer grind size. Bottle roll tests were completed on whole ore samples, i.e. with no prior treatment with gravity. Cyanidation recovery was observed to vary from 89.4% to 94.5%. 13.13.2

2012-2013 Comminution and Metallurgical Test Work

The comminution and metallurgical test work program for Block A was completed in January 2013 by BBA. The testing was conducted at SGS Lakefield, Ontario. The goal of the metallurgical test work program was to determine if the mineralized material of the Block A deposit have similar characteristics than the Detour Lake ore and to evaluate the possibility of potentially processing the Block A mineralized material at the Detour Lake process plant. A total of 61 samples were subjected to comminution tests. The following tests were executed to evaluate the crushing and grinding characteristics of the Block A mineralized material and compare them to the Detour Lake ore:  4 February 2014

JK Drop-Weight Test (DWT) and SAG Mill Comminution (SMC) Test; 13-17

Mineral Processing and Metallurgical Testing



Bond Low Energy Impact Test (Crushing Work Index, CWi);



Bond Rod Mill Work Index (RWi) and Bond Ball Mill Work Index (BWi);



Bond Abrasion (Ai) Test, Point Load Index Test; and



Relative Density Measurements.

The test work was planned to characterize the mineralized material (and lithologies), determine gold head grade-recovery relationship, retention time, cyanide consumption and copper dissolution profiles. Comminution Test Work A total of 17 HQ drill holes totaling 2,915 metres were drilled between March 2012 and May 2012 for the purpose of metallurgical testing. Figure 13-6 shows the locations of the selected HQ drill core sampling points. The holes were logged using the same logging procedure as the previous test work program at Detour Lake. Rock samples were selected from intervals that represented the four main rock types (lithologies) present in Block A: CG, KPF, PF, MF (very similar lithologies to Detour Lake). Figure 13-6 Sampling Locations for Comminution Test Work

The results of the comminution tests carried out on the selected samples provided sufficient information to characterize the grinding/crushing properties of the Block A deposit. This information can be used for crushing/grinding circuit design (simulations, equipment sizing, etc.). Table 13-8 summarizes the comparison between Detour Lake and Block A based on the 75th percentile test results. When comparing the 75th percentile comminution characteristics of the Block A deposit with those of Detour Lake, it can be seen that although the two zones are categorized as hard in terms of both DWT resistance to impact (Axb value) and abrasion breakage (ta value), the mineralized material from Block A is slightly softer (in terms of RWi and BWi) and less abrasive (Ai) than the Detour Lake ore.

13-18

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Table 13-8

Comminution Test Result Comparison between Detour Lake and Block A

JKTech Parameters Deposit

Relative Density

SG

Work Indices

Axb SMC

DWI 3 kWh/m

Wax g/cm3

SMC g/cm3

Pycno g/cm3

CWI kWh/t

RWI kWh/t

BWI kWh/t

Ai g

Detour Lake

24.3

11.4

2.98

2.98

2.93

16.9

18.9

15.5

0.54

Block A

24.8

11.6

2.98

2.97

2.99

16.4

17.1

13.2

0.387

-3%

-10%

-15%

-28%

% Difference

Metallurgical Test Work The samples for test work were selected from the half NQ drill cores available at site. Thirteen (13) gold grade bin samples were determined. The samples were selected from drill hole intervals that represent the four (4) main lithologies present in Block A. Approximately 1,500 samples were selected and sent to SGS Minerals for metallurgical test work. A second batch of samples was used to study the response of the main rock types (namely the ORT composites from three (3) different zones; i.e. West, Center and East) to gravity and leaching. The rejects from the comminution test work were used to study the spatial performance of the Block A mineralized material. The samples represented three main lithologies: CG, KPF and PF. The metallurgical test work program included the gravity separation and cyanide leaching of the gravity tailings for the Grade Variation (“GV”), Overall Rock Type (“ORT”) and comminution reject (CR) composites. The test work results indicated that the recovery profiles from gravity separation testing of Block A - GV composites are similar to Detour Lake feasibility study test work results (Figure 13-7.). Furthermore, as can be seen from the comparison in Figure 13-8, the gravity plus cyanidation recovery response to head grade for Block A - GV composites was also similar to that of the Detour Lake samples. This indicates that the Block A mineralized material can be treated at the Detour Lake process plant. Cyanide consumption profiles for Detour Lake and Block A are similar; however, the results indicate that Block A mineralized material consumes approximately 10% more cyanide than Detour Lake ore (i.e. 0.33 kg/t for Detour Lake vs. 0.39 kg/t for Block A). In conclusion, the recovery models developed for the Detour Lake mine can be used to represent the performance of the Block A mineralized material.

4 February 2014

13-19

Mineral Processing and Metallurgical Testing

Figure 13-7 Comparison between Gravity Separation Performance for Detour Lake and Block A GV and ORT Samples

Gravity Recovery vs Calculated Head Grade 100 90

Gold Recovery, %Au

80 70 60 50 Block A Com Rejects Detour Lake Block A‐GV Block A‐ORT Log. (Detour Lake) Log. (Block A‐GV)

40 30 20 10 0 0

1

2

3 4 5 6 Calculated head grade, g Au/t

7

8

9

10

Blue diamond: Detour Lake Red diamonds: Block A GV Green square: Block A ORT

Figure 13-8 Comparison of Gravity Separation + Cyanidation Recovery Performance for Detour Lake and Block A

Blue diamond: Detour Lake Red diamonds: Block A GV Green square: Block A ORT

13-20

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

13.14 Conclusion As part of the review of the test work for the feasibility study, BBA re-evaluated the overall gold recovery models developed for the pre-feasibility study and determined that the models are valid. Results from the Detour Lake feasibility study test work program did not show benefit in gold leaching from tests conducted with lead nitrate. However, it was found that lead nitrate catalyzed the copper leaching, thus lead nitrate was not included in the leaching circuit. The mineral processing requirements and supporting metallurgical testing assumed the results from the feasibility study. The ore hardness and gold recovery from east to west did not show directional change in results and are consistent along the strike of mineralized domains. Since the geology within the mineralized domains does not change along strike (i.e. core logs, visual mineralization or drill penetration rate), BBA was comfortable in extrapolating the test work from the feasibility study. If further extensions to the west were to be included as part of the Detour Lake mineral reserves, a confirmation test work program is recommended. Review of the process plant data from October to December 2013 indicated that the gold recovery was 1% to 3% higher than predicted by the pre-feasibility and feasibility studies model. Based on this data, a 1% gold recovery increase was added to the gold recovery model used for the LOM plan. The Block A metallurgical test work program showed that the grinding, crushing and gold gravity recovery, and cyanide leach characteristics are similar to the Detour Lake samples. The Block A mineralized material can thus be milled in the Detour Lake process plant with the same throughput and recoveries. The Detour Lake recovery models can be used to represent the performance of the Block A mineralized material. As for the throughput, the hardness appears to be lower by approximately 10% but the overall impact on tonnage has yet to be fully evaluated.

4 February 2014

13-21

Detour Lake Mine NI 43-101 Technical Report

14.0 Mineral Resource Estimates 14.1 Introduction This section presents the results of the MRE for the Property which is based on added analytical data sampled from the drilling program completed since the prior mineral resource estimation. The Property hosts the Detour Lake mine and the Block A deposit located immediately to the west. The Detour Lake mine MREs are contained between sections 16,510E and 20,700E (block centers), and between sections 19,555N and 20,745N, covering the entire mine operations (open pit design). The Block A MREs are contained between sections 14,600E and 17,430E, and between sections 19,740N and 21,285N, covering the western portion of the Detour Lake mine. An overlap area between sections 16,510E and 17,430E is present between the Block A and Detour Lake mine. This buffer was used for geological modeling, grade continuity, geostatistical analysis and resources estimation purposes. This buffer was considered during resource estimation. For resource reporting, the Block A resource model was utilized west of section 16,995E and the Detour Lake mine resource model was utilized east of section 16,995E. The prior MREs for Detour Lake were completed by SGS Geostat and disclosed in the Company news release dated January 25, 2012 and in technical report (BBA, 2012). The new MREs are defined based on the open pit mining scenario provided by Detour Gold, using a base case CoG of 0.5 g/t Au for Detour Lake. The MREs are presented within the constraints of an optimized pit shell and are reported as in-pit mineral resources. The Block A deposit MREs were completed by WGM (2011) and disclosed by Trade Winds in their news release dated December 30, 2010. Trade Winds were the operator of the Block A joint venture at the time. SGS Geostat updated the MREs based the open pit mining scenario provided by Detour Gold, using a base case CoG of 0.6 g/t Au. The MREs are presented within the constraints of an optimized pit shell and are reported as inpit mineral resources. Both the Detour Lake mine and Block A deposit MREs were prepared by Yann Camus, Eng., senior geological engineer and qualified person under NI 43-101 guidelines using the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Standards on Mineral Resources and Reserves, Definitions and Guidelines prepared by the CIM Standing Committee on Reserve Definitions and adopted by the CIM Council on December 11, 2005. A summary of the in-pit mineral resources (exclusive of mineral reserves) for both Detour Lake and Block A, as of year-end 2013, is shown in Table 14-1. The Measured and Indicated mineral resources total 136.3 Mt averaging 1.11 g/t Au for a total of 4.87 million ounces of gold. In addition, the Inferred mineral resources total 21.7 Mt averaging 0.81 g/t Au for a total of 564,000 ounces of gold.

4 February 2014

14-1

Mineral Resource Estimates

Table 14-1

Detour Gold Mineral Resources1, 2, 3, 4, 5 Effective December 31, 2013 Contained Gold Ounces (000's)

Tonnes (millions)

Grade (g/t Au)

Measured (M)

16.4

1.37

725

Indicated (I)

65.9

1.01

2,150

M+I

82.4

1.09

2,874

1.5

1.21

57

52.5

1.15

1,934

Area/Category Detour Lake Mine

Block A Measured (M) Indicated (I) M+I Total M+I

53.9

1.15

1,991

136.3

1.11

4,866

19.2

0.75

465

2.5

1.23

99

21.7

0.81

564

Detour Lake Mine Inferred Block A Inferred Total Inferred 1

CIM definitions were followed for mineral resources. 2 The cut-off grades used are 0.5 g/t Au for Detour Lake mine and 0.6 g/t Au for Block A. 3 Mineral resources were calculated using a gold price of US$1,200/oz. 4 Mineral resources are exclusive of mineral reserves. Mineral resources that are not mineral reserves do not have demonstrated economic viability. 5 Capping grades estimated by domains and vary from 15 m. g/t to 75 m. g/t Au.

SGS Geostat completed and updated the Detour Lake mine and Block A deposit block models based on information provided by Detour Gold. Once both block models were updated, SGS Geostat completed the mineral resources estimation for both models. The MRE is derived from a computerized resource block model. The Block Model construction relies on drill hole data, which serve as the basis for the definition of 3D mineralized envelopes. Mineral resources were limited to the material inside of those mineralized envelopes. Fixed length composites were used for interpolation. Blocks from a regular grid filled these mineralized envelopes. Blocks were assigned a grade according to the estimation method and composites available inside respective solids. Once estimated, blocks were classified based on their proximity to nearby composites and the corresponding confidence level. Resources were tabulated after adjusting block tonnages for material contained within prior mined-out pit, stopes, overburden/bedrock contact or pit bottom surface. SGS Geostat believes that the assumptions, parameters, and interpretation are reasonable and appropriate for both deposits. Moreover, SGS Geostat finds the model and estimate acceptable and supports the current MREs. As of the date of this Technical Report, SGS Geostat is not aware of any environmental, permitting, legal, title, taxation, socio-economic, marketing, political, or other relevant factors that could materially affect the current MREs. 14-2

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

14.2 Detour Lake Mine Resource Estimates 14.2.1 Detour Lake Mine Data The MRE of the Detour Lake deposit was completed using the data from the historic drilling and Detour Gold’s drilling from 2007 to 2012. Sample data used in the construction of the proposed resource model was in a drill hole database received from Detour Gold on June 7, 2013. Table 14-2 summarizes the records in the database used for this MRE. Table 14-2

Summary of Database Number of Drill Holes

2011 Estimation 2013 Additional data (inside 23 of the 2011 holes) 2013 Additional holes Total

Length (m)

Survey

Lithology

6,475

1,134,287

121,838

113,638

996,566

0

1,025

47

50

11,986

Surface

UG*

Total

1,803

4,672

0

0

Assay

34

0

34

6,844

191

228

7,017

1,837

4,672

6,509

1,142,156

122,076

113,916

1,015,569

* Underground

Detour Gold’s drilling (“DG” series) from 2007 to 2012 accounts for 1,263 surface holes totaling 540,172 metres drilled. The DG series surface holes are generally dipping 50° to the south on N-S cross-sections at 40 metres spacing and with the same 40 metres vertical spacing between holes on the same section. In a few specific sectors, that horizontal/vertical spacing is reduced to 20 metres. With a total of 519,011 assay intervals being from DG holes, they comprise more than 50% of the assay information. 14.2.2 Detour Lake Mine Geological Interpretation In 2011 and 2013, the Detour Gold geology department and Thon Consulting updated the wireframe model using Datamine 3D modeling software, based on the drilling database available at the time. In 2013, updated wireframes for domains 04, 10 and 12 were received. On October 25, 2013, updated wireframes together with the outer shell, topography and overburden surfaces were received as DXF files for all domains from Detour Gold, with the following details. 

DXF files for open surfaces: topo surface + overburden/bedrock contact surface;



DXF files for old underground openings (separated in stopes and workings);



DXF files for mineralized domain solids i.e. 01, 02, 03, 04, 05, 06, 07, 08, 10, 11 and 09 (outer shell); DXF files for mostly barren intrusives (thereafter coded Domain 12); and



In 2013, DXF file updates for mineralized domain solids i.e. 04, 10 and 12.

Since the new information is all located to the western limit of the model, it was determined by SGS Geostat that the modification of domains between 2011 and 2013 affected only 0.2% of the tonnage and gold content of the 2011 resource inside pit LG721 at a CoG of 0.5 g/t Au. Due to the very small changes observed, it was deemed 4 February 2014

14-3

Mineral Resource Estimates

unnecessary to update the material within that area. Future changes to the model based on production data will have a larger impact on the results. In order to design the solids for each mineralized domain, Detour Gold’s geologists have interpreted limits of mineralized domains on sections and benches. Those domains correspond to broad zones with a higher than usual concentration of samples with potentially economic gold grades. Domain 1 corresponds to the CMH which crosses most of the Detour Lake deposit from east to west with a well-defined flexure on the east side. All the other mineralized domains are built around Domain 1. The supplied mineralized solids and drill hole samples cover a 4,200 x 1,700 metre area from sections 16,500E/19,100N to 20,700E/20,800N. The bottom of the interpretation is at Z=5,390EL while the topographic surface rarely exceeds Z=6,300EL hence a 910 metre vertical span. Drill hole samples are mostly north of the mineralized Domain 1 (CMH), a narrow corridor about 10 metres wide. Other mineralized domains are E-W elongated and sub-vertical dips: to the north, from the CMH, are Domains 8, 11, 2, 3, then Domains 4, 5 and a new marker zone identified as Domain 10, which is mostly recognized on the west extension of the deposit. Domains 6 and 7 are south of the CMH, mostly on the east side, and on both sides of an ultramafic intrusive (Domain 12) (Figure 14-1). All potentially mineralized material left between non-specific domains is included in an outside shell, labeled as Domain 9. Figure 14-1 Detour Lake Isometric View of the Open Pit Showing Mineralized Domains

14-4

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

14.2.3 Detour Lake Mine Capping Most of the gold values in the more than one million drill hole assay intervals are of lowergrade, but some results returned anomalously high gold values. The anomalous values needed to be capped before being used for block grade interpolation. SGS Geostat used a standard approach to capping high-grade gold values consisting of developing probability plots to search for any natural gap in those distributions. As illustrated in Table 14-3, the very high-grade intervals might have different lengths (from 0.30 metre to 1.52 metres for the 39 intervals with a grade above 300 g/t Au). To accurately compare the anomalous high gold assay values (a high gold grade is more likely to occur in a short interval), SGS Geostat looked at distributions of grade multiplied by the sample interval length (“GT Products”). Only 1 assay added since the 2011 estimation is above 300 g/t and is inside hole DG-12-1207. Table 14-3

Detour Lake Drill Hole Assay Intervals with Gold Values above 300 g/t

From

To

Length

Au

(m)

(m)

(m)

(g/t)

38-046

239.00

239.30

0.30

1,814.00

11

DG-07-044

224.50

225.00

0.50

1,434.00

TWDDH-143

108.75

109.25

0.50

1,010.00

DG-08-351

378.00

379.00

1.00

DG-07-140

135.90

136.40

0.50

Hole

From

To

Length

Au

(m)

(m)

(m)

(g/t)

07-0035

103.00

104.00

1.00

412.50

7

8

DG-08-530

113.00

113.50

0.50

411.51

11

9

DG-08-351

177.00

178.00

1.00

397.28

3

848.95

9

PMDDH-080

43.80

44.30

0.50

389.95

11

782.84

11

DG-07-270

188.00

189.00

1.00

385.44

2

Domain

Hole

Domain

DG-08-540

470.60

471.10

0.50

704.80

11

DG-07-117

259.50

260.0

0.50

377.71

2

07-0585

161.00

162.00

1.00

680.40

2

DG-08-302

96.50

97.00

0.50

376.3

2

38-046

221.80

222.10

0.30

591.80

11

38-003

98.20

98.50

0.30

366.20

11

PMDDH-104

112.50

113.00

0.50

574.

11

15-0761

13.00

14.00

1.00

350.50

9

56.50

57.00

0.50

572.15

11

DG-08-353

586.00

586.50

0.50

338.02

2

DG-08-369

459.00

459.50

0.50

565.55

2

DG-07-077

278.70

279.20

0.50

334.86

2

DG-10-892

354.50

355.00

0.50

551.70

3

11-0794

11.00

12.00

1.00

324.00

11

DG-09-618

146.50

147.00

0.50

536.06

2

DG-07-018

327.50

328.00

0.50

322.09

11

PMDDH-077

207.40

207.90

0.50

488.66

11

DG-07-234

306.20

306.70

0.50

320.51

8

2.00

3.00

1.00

481.23

9

DG-07-117

260.00

260.50

0.50

313.92

2

DG-07-016

296.80

297.30

0.50

461.64

11

11-0052

143.00

144.00

1.00

312.50

11

DG10-886

67.50

68.00

0.50

449.65

9

38U-063

13.70

15.20

1.50

308.60

1

DG-07-108

15-0715

DG-08-606A

623.00

624.00

1.00

449.51

2

DG-07-118

64.00

64.50

0.50

305.98

11

11-0974

192.00

193.00

1.00

427.00

11

DG-08-473B

249.00

249.50

0.50

305.66

2

DG12-1207

259.00

259.50

0.50

422.70

9

11-0540

103.00

104.00

1.00

300.00

2

For the 2013 resource update, the number of assays added represents less than 2% of the 2011 assays number. Therefore it was decided not to revise gold capping threshold. The 2011 methodology was used and is presented here. The 2013 capping statistics presented in Table 14-4 show that only a few high grades are capped inside the 9 and 12 domains but they represent an important amount of the total metal content. Grades inside the 10 domain seem low compared to 2011 average. 4 February 2014

14-5

Mineral Resource Estimates

Distributions of GT Products for original assay intervals have been examined for each of the mineralized domains (examples in Figure 14-2). As shown in previous studies (SGS Geostat 2008a, 2008c, 2009a) and included in prior technical reports (Met-Chem 2009, BBA 2010 and 2011), GT Products distributions are limited to drill hole assay intervals with a GT Product over 0.3 m. g/t Au (0.3 g/t Au over one metre), which is close to the limit for “mineralized” samples. Sensitivity analysis shows that the shape of cumulative frequency plots for high GT Product data changes very little when the lower limit varies from 0.2 to 0.5 m. g/t Au. In almost all cases, the cumulative frequency plots for high GT Products on a log scale do not show any obvious abrupt change of slope, which, if present, would correspond to a natural gap in the data. As a result, it can be concluded that the selected cap limits are fairly subjective. As such, upper limits for capping are chosen to correspond to the same percentage of lost gold in each of the mineralized domains. The final selection is based on average grade of all composites in each domain with the highest cap of 50 m. g/t (50 g/t over 1 metre) in Domain 1 with the highest average GT of about 2.3 m. g/t. The overall gold lost amounts to 9%, which remained at the same level as the MRE in the feasibility study (BBA, 2010). Table 14-4 shows the effect of those capping limits on the statistics of gold values. Table 14-5 shows the effect on the new data of this update. It shows that the gold lost on the 2013 added data is of 14% and therefore the capping on the updated data could be considered conservative. Table 14-4

Domain

Detour Lake Capping Limits for GTs of Original Sample in 2011 Data

Nb. GT

Avg. GT (m. g/t) 2.293

Capping (m. g/t) 50

Nb. Capped

% Capped

Avg. GT Capped (m. g/t)

% GT Lost

118

0.32

2.171

5.3

1

36,504

2

126,360

0.910

30

384

0.3

0.801

12

3

81,337

0.674

25

169

0.21

0.623

7.6

4

42,500

0.625

25

72

0.17

0.554

11.4

5

8,938

0.586

25

9

0.1

0.562

4.1

6

7,609

1.721

40

30

0.39

1.603

6.9

7

46,843

1.529

40

121

0.26

1.462

4.4

8

61,027

0.902

30

187

0.31

0.816

9.5

10

2,689

0.523

25

9

0.33

0.421

19.5

11

171,493

1.385

40

546

0.32

1.266

8.6

585,300

1.134

1,645

0.28

1.04

8.4

10,486

0.057

15

3

0.03

0.055

3.5

9

399,970

0.235

15

514

0.13

0.208

11.5

All

995,756

0.762

2,162

0.22

0.695

8.8

Subtotal 12

Note: Domain 12 is the barren intrusive to the west.

14-6

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Table 14-5

Capping Limits for GTs of Original Sample Added to 2013 Data

Nb. GT

Domain

Avg. GT (m. g/t)

Capping (m. g/t)

Nb. Capped

% Capped

Avg. GT Capped (m. g/t)

% GT Lost

1

0

0.000

50

NA

NA

NA

NA

2

596

1.374

30

3

0.5

1.258

8.4

3

1,821

0.758

25

7

0.4

0.669

11.7

4

3,170

0.632

25

5

0.2

0.567

10.2

5

0

0.000

25

NA

NA

NA

NA

6

0

0.000

40

NA

NA

NA

NA

7

0

0.000

40

NA

NA

NA

NA

8

0

0.000

30

NA

NA

NA

NA

324

0.086

25

0

0.0

0.086

0.0

40

NA

NA

NA

NA

15

0.3

0.642

10.3

10 11

0

0.000

5,911

0.715

278

0.408

15

1

0.4

0.216

47.1

9

12,814

0.145

15

11

0.1

0.116

19.9

All

19,003

0.326

27

0.1

0.281

13.8

Subtotal 12

Note: Domain 12 is the barren intrusive to the west.

Figure 14-2 Examples of Detour Lake GT Cumulative Frequency Plots of 2011 Data in Mineralized Domains

1000

Detour Lake - November 2011 - Domain A11 - GT>0.3

1000

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80

4 February 2014

90

95

98

99

99.8

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" "

"" "

"""""""" " """" """""" """"""""" """ """""""""" """""" """"" """"" """ """"""" """"""""""" " " " " """ """"""" """" "" """" """"" """"" """" """"""""" """"" """"""""" """" """""" """"""""" """"" """""""" """"""" """""""" " " " " " """"""" """"""" """""" """""" """""""" """"""""" """"""" """""""" """""" """""""" """""" """""" """""""" """"" """"" """"""" """""" """""" """""" " " " " " "" """""""" """"""" """""" """""" """""" """""" """"""" """"""" """""""" """"" """""" """"""" """""""" """""" """"""" """""" """""""" """""""" " " " " " " """"""" """"" """""""" """""" """"""" """""" """""" """""""" """""""" """""""" """""""" """"""" """"""""" """""""""" """""" """""""""" """"""" """"""" " " " " " " " """"""""" """"""" """"""" """"""" """"""" """"""" """""""" """""""" """"""""" """""""" """"""""" """"""""" """" """"""""" """"""""" """"""""""" """" """"""""""" " " " " """"""" """"" """""""""""" """" """"""""""""" """" """""""""""""" """"" """""""""""""" """"" """""

100

Cumulative Freq [%]

1

Detour Lake - November 2011 - Domain A2 - GT>0.3 gtau

Cumulative Freq [%]

1 50

70

80

90

95

98

99

99.8

99.99

14-7

Mineral Resource Estimates

14.2.4 Detour Lake Mine Composites The 2013 composites were done using the same methodology as in 2011. The 2011 variograms and block size were also retained without changes for the update of the resource. Table 14-6 shows results of capped and uncapped composites for the 2011 and 2013 data. The spatial continuity analysis of gold grade in each specific mineralized domain was done on the 2011 capped grade of the 5 metre down-hole composites. This composite size is selected to match the 5 metre N-S thickness of the 10 x 5 x 12-metre resource blocks to be interpolated. The intent of selecting composites with length similar to the mineralized block intercepts is to ensure that grade dilution originating from the block size will be included in the grade of samples used for interpolation. Individual assays are capped prior to compositing. Table 14-7 lists some statistics of the computed grade of the 5 metre composites in domains untouched since the 2011 estimation. Only composites of at least half the nominal composite length (thus 2.5 metres) are used for the estimate. Comparison of the composited grades within the Detour Gold holes versus historical drill holes showed relevant discrepancies. By assigning a default grade of 0.01 g/t Au to all missing assay values within the historical drill holes (referred to as padding), these discrepancies were diminished. The routine of padding with "dummy intervals" of near zero grade values was implemented before the compositing. Compositing starts at the overburden-bedrock contact. Statistical data in Table 14-7 indicates the coefficient of variation (CV) values in the range of 150% or higher. Table 14-6

Detour Lake Statistics of 5 metre Uncapped and Capped 2011 and 2013 Composite Grades only for Affected Domains

Domain Count

2011 Estimates

3

4

9

10

12

145,708

25,558

16,540

8,939

91,249

578

2,844

0.00

0.00

0.00

0.00

0.00

0.00

0.00

Median (g/t Au)

0.10

0.30

0.26

0.18

0.05

0.09

0.01

Average (g/t Au)

0.39

0.90

0.66

0.51

0.20

0.48

0.04

169.84

139.08

87.93

57.43

169.84

21.41

8.49

AuCap ave (g/t Au)

0.35

0.79

0.61

0.45

0.18

0.39

0.04

AuCap max (g/t Au)

32.41

32.41

13.40

12.49

13.94

8.16

6.49

149,261

25,666

16,876

9,522

93,659

639

2,899

0.00

0.00

0.00

0.00

0.00

0.00

0.00

Max (g/t Au)

Min (g/t Au)

14-8

2

Min (g/t Au)

Count

2013 Update

All Affected

Median (g/t Au)

0.10

0.30

0.26

0.19

0.04

0.08

0.01

Average (g/t Au)

0.39

0.90

0.66

0.52

0.20

0.45

0.05

169.84

139.08

87.93

57.43

169.84

21.41

14.06

AuCap ave (g/t Au)

0.35

0.79

0.61

0.46

0.18

0.36

0.05

AuCap max (g/t Au)

32.41

32.41

13.40

12.49

13.94

8.16

6.49

Max (g/t Au)

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Table 14-7

Domain

Number Composites

Detour Lake Statistics of 5 metre Uncapped and Capped 2011 Composite Grades for Unchanged Domains Min. (g/t Au)

Max. Uncap (g/t Au)

Median (g/t Au)

Max. Cap (g/t Au)

Avg. Uncap (g/t Au)

Avg. Cap (g/t Au)

Coeff. Var. Uncut (%)

Coeff. Var. Cut (%)

1 5 6 7 8 11

7,777 1,896 2,008 9,817 12,999 36,231

0 0 0 0 0 0

0.96 0.26 0.44 0.56 0.27 0.49

79.63 26.61 33.76 91.4 143.46 109.36

23.08 9.7 15.91 26.81 19.88 29.76

2.13 0.56 1.31 1.46 0.86 1.31

2.01 0.53 1.22 1.39 0.77 1.2

164 198 195 193 275 221

137 156 163 163 178 160

All

70,728

0

0.46

143.46

29.76

1.32

1.22

216

164

Histograms of composite grades for each domain are shown in Figure 14-3. All distributions show a peak at 0.1 g/t Au that corresponds to the default value of low-grade intervals in older drill holes plus another one at 0.01 g/t Au that corresponds to padded intervals. Moving from well-mineralized domains (1, 11, 6 and 7) into lower grade domains (4, 5 and 9), the proportion of composites with values within the 0.01 to 0.1 g/t Au range is increasing. A negative skewness of values above the default is observed within the higher grade domains while a positive skewness of the identical data is observed in the lower grade domains. Figure 14-3 Examples of Detour Lake Histogram of 5 metre Composite Grades per Domain

7.00

Detour Lake. November 2011. 5m composites in domain 11

6.63

Relative Freq

6.30

5.96

5.60

5.30

4.90

4.64

4.20

3.98

3.50

3.31

2.80

2.65

2.10

1.99

1.40

1.33

0.66

0.70

0.00 0.010

Detour Lake. November 2011. 5m composites in domain 02 Relative Freq

AuCut 0.023

0.051

4 February 2014

0.116

0.262

0.592

1.338

3.026

6.843

15.476

35.000

0.00 0.010

AuCut 0.023

0.051

0.116

0.262

0.592

1.338

3.026

6.843

15.476

14-9

35.000

Mineral Resource Estimates

14.2.5 Detour Lake Mine Spatial Analysis The 2011 variograms were retained without changes for the update of the resource and are documented in this section. Spatial continuity of the grade of composites in each domain is assessed through correlograms (the calculated correlation coefficient of grades from pairs of composites separated by a given distance in a given direction). Some examples of experimental correlograms are presented as variograms (Figure 14-4). Directions investigated are the E-W horizontal average strike, the vertical average dip, the horizontal N-S across average strike and dip, as well as two intermediate directions in EW vertical planes (i.e. a dip of 45° to west and a dip of 45° to east). In each case, the average downhole correlogram (along drill holes) is also calculated to better assess the magnitude of the nugget effect. Results of variogram models (Table 14-8) show that: 

A significant relative nugget effect from 60% to 70%;



A generally well-defined anisotropies with best continuity (lowest curve) along the average E-W horizontal strike (dip to west); and



The poorest continuity (highest curve) across dip and strike; and intermediate continuity along the average vertical dip to east; (refer to Figure 14-3 and Table 14-8).

Table 14-8

Domain

Nugget

C1

Detour Lake Variogram Models of 5 metre Composites in the Mineralized Domains AEW1

AZ1

ANS1

(m)

(m)

(m)

C2

0.2

AEW2

AZ2

ANS2

Az

Dip

Spin

(m)

(m)

(m)

(°)

(°)

(°)

150

90

15

1

0.6

0.2

45

30

15

270

-40

90

2

0.7

0.3

120

45

18

270

-10

90

3

0.65

0.35

90

60

30

270

-20

90

4

0.7

0.1

15

15

10

0.2

150

75

45

270

0

90

5

0.6

0.2

30

30

10

0.2

150

90

30

270

-20

70

6

0.6

0.4

120

45

20

255

-40

70

7

0.6

0.4

180

30

30

255

-40

70

8

0.7

0.3

150

75

30

270

-10

90

9

0.65

0.35

180

90

45

270

-10

90

10

0.7

0.3

90

90

30

0

-75

0

11

0.7

0.3

150

75

30

260

-20

90

12

0.7

0.3

60

60

30

0

-75

0

Note: Each model is the sum of a nugget effect and up to two exponential component functions. “C” is the sill of the exponential function. “A” is the range (in metres) of the function along the principal direction. Az/Dip are the azimuth (positive from north) and dip (negative downward) of the direction with the longest range. For example, in Domain 2, the long range is along a direction dipping 10° to west and “Spin” is the third rotation angle around the direction of the longest range (Az/Dip) to put the direction of the short range into place. In Domain 2 the 90° spin puts the direction of short range along the horizontal N-S.

14-10

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Figure 14-4 Examples of Detour Lake Correlograms of the Capped Grade of 5 metre Composites per Mineralized Domains

Note: Correlograms are presented as variograms (graph is “1-correlogram”). They are computed along E-W (red), N-S (green), vertical (blue), dip 45° to west (beige) and dip 45° to east (brown). For each direction, the experimental graph and the fitted model are shown. An average correlogram (black) is also presented. Note that the vertical scale is generally from 0.5 (not zero) to 1.2. Calculation parameters for each direction and the equation of the fitted model are given in the legend box at the bottom of each plot.

14.2.6 Detour Lake Mine Resource Block Modeling Drill hole spacing across the deposit is generally on the order of 40 metres in the N-S and E-W direction. The 2011 block size was retained without changes for the update of the mineral resource. A block size of 10 x 5 x 12 metres was selected to accommodate the drill hole spacing and width of the mineralization. The 10-metre E-W dimension corresponds to approximately half the minimum spacing between Detour Gold surface holes. The 5 metre N-S dimension accounts for the perceived greater grade variability along that direction while the 12 metre vertical dimension corresponds to the bench height recommended by BBA. Given a density of 2.9 t/m3, each full block 10 x 5 x 12-metres weighs about 1,740 tonnes and it is a reasonable assumption for the selection mining unit or minimum size block which can be selectively extracted as ore or waste in the open pit operation. Table 14-9 summarizes the block limit co-ordinates for the Detour Lake block model. All blocks completely above the overburden/bedrock contact surface or outside mineralized Domains 1 to 12 are eliminated, reducing the actual final number of blocks. An overlap area between sections 16,500E and 17,600E is present between the Block A and Detour Lake mine models. The purpose of this buffer zone was for the added information for geological modeling, grade continuity, geostatistical analysis and resources estimation purposes. All data (DDH, composites, domain volumes, geological interpretations) present in the buffer zone was used for resources estimation purposes. Only block edges falling entirely within the Table 14-9 were retained in the MREs further below.

4 February 2014

14-11

Mineral Resource Estimates

Table 14-9

Detour Lake Resource Block Model Parameters (edges) Coordinate

Number of Blocks

Minimum (m)

Maximum (m)

Easting

420

16,695.0

20,705.0

Northing

340

19,102.5

20,802.5

Elevation

76

5,388.0

6,300.0

Table 14-10 shows the details of the assignment of blocks to the mineralized domains with corresponding volume and tonnage, after excluding block portion for the old pit (Campbell Pit) and old underground stopes volumes. The majority of old underground stopes are concentrated in Domain 1 (CMH) and Domain 11. Figure 14-5 and Figure 14-6 illustrate the block assignment to domains on a bench and sections. Table 14-10 Detour Lake Volumetric of 10 x 5 x 12 metre Blocks by Domain and Total Nb blocks below ovbd

Volume below ovbd (m3)

Volume below ovbd+pit (m3)

Volume in pit (m3)

Volume stope (m3)

1

55,183

32,899,998

32,280,666

619,332

1,698,758

30,581,909

2

157,407

93,850,801

93,850,801

0

75,465

93,775,336

3

164,481

98,067,778

98,067,778

0

49,425

98,018,353

4

190,504

114,047,552

114,047,552

0

28,598

114,018,955

5

12,106

7,127,158

7,127,158

0

8,475

7,118,683

6

5,840

3,373,912

2,431,518

942,394

79,110

2,352,408

7

52,025

31,066,942

30,904,657

162,285

666,900

30,237,757

8

81,584

48,806,666

48,806,666

0

144,743

48,661,924

10

69,823

41,675,008

41,675,008

0

0

41,675,008

11

124,373

73,558,514

70,956,624

2,601,890

2,674,868

68,281,757

Subtotal

913,326

544,474,328

540,148,427

4,325,901

5,426,340

534,722,087

Domain

12 (Intrusives)

Volume left (m3)

151,846

90,268,857

90,268,857

0

0

90,268,857

9

3,431,374

2,036,572,990

2,034,756,794

1,816,196

535,770

2,034,221,024

All

4,496,546

2,671,316,176

2,665,174,078

6,142,097

5,962,110

2,659,211,968

14-12

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Figure 14-5 Detour Lake Bench 6,198 with Blocks in Mineralized Domains

Domain 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Note: Blocks in the 12-metre bench are coloured according to mineralized domain. Blocks in (barren) intrusives to the west are in pink (Domain 12). Limits of the final pit in the same bench are also shown. Only blocks which could ultimately be estimated are shown (missing blocks are mostly in Domain 9 in grey).

4 February 2014

14-13

Mineral Resource Estimates

Figure 14-6 Detour Lake Sections 17,000E and 19,300E with Blocks in Mineralized Domains

Note: Blocks in the 10-metre section are coloured according to mineralized domain. Limits of the final pit in the same section are also shown. Blocks in (barren) intrusives to the west are in pink (Domain 12). Only blocks, which could ultimately be estimated, are shown (missing blocks are mostly in Domain 9 in grey).

14.2.7 Detour Lake Mine Block Grade Interpolation The interpolation of the Detour Lake resource model was completed using ordinary kriging (OK) methodology. Search volume dimensions are defined from the variogram models. Limits are set for the minimum and maximum number of samples (composites) used per estimate and as a restriction on the maximum number of samples used from each hole. The 2011 methodology was retained. The estimation was designed as a four-pass system as outlined in Table 14-11. In the first pass, the search ellipse distance was generally 50 metres (X) by 10 metres (Y) by 20-30 metres (Z), a minimum of five composites was required and a maximum of 20 composites were allowed, with a maximum of three composites from any one hole, which implies a minimum of two holes required in order to estimate a block. The search distance in the second pass was two times the search distance of the first pass. For the third pass, the search distance was three times that of the first pass. A fourth pass was used where required in order to capture areas with missing blocks for the Inferred resources. The search distance used for this last pass was four times of the first run, using the same anisotropy. The minimum number of composites was five and maximum 35 from at least two different holes. Multiple dip and dip directions were used per domain. A “panel” approach was used to set local orientation. The panels were limited by ranges of easting and elevation. Figure 14-7 illustrates examples of the local orientation for some of the most important domains. The majority of the blocks are interpolated in the first pass with the more constrained search conditions with the exception of Domain 9, which represents the background of the model. The estimation of block grades is illustrated on a few benches and sections (Figure 14-8 and Figure 14-9). Statistics for the interpolation for Detour Lake mine are summarized in Table 14-11.

14-14

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Table 14-11 Detour Lake Block Model Estimation Parameters Domain

Pass

1

2

3

4

5 6

7

8

9

10

11

12

1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 1 2 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 1 2 3 1 2 3 4

RMAX

RINT

RMIN

Az

Dip

Spin

Min. Comp.

Max. Comp /Hole 2

(m)

(m)

(m)

(deg)

(deg)

(deg)

50 100 150 200 50 100 150 200 50 100 150 250 50 100 150 200 50 100 50 150 50 100 150 250 50 100 150 200 50 100 150 200 50 100 150 50 100 200 50 100 150 200

30 60 90 120 20 40 60 80 30 60 90 150 25 50 75 100 30 60 20 60 20 40 60 150 25 50 75 100 30 60 90 120 50 100 150 25 50 120 50 100 150 200

30 60 90 120 10 20 30 40 10 20 30 50 15 30 45 60 10 20 10 30 10 20 30 100 10 20 30 40 15 30 45 60 20 40 60 10 20 50 25 50 75 100

270

-40

90

5

270

-10

90

5

3

270

-20

90

5

3

270

0

90

5

3

270

-20

90

5

3

255

-40

70

5

3

255

-40

70

5

3

270

-10

90

5

3

270

-10

90

5

3

0

-75

0

5

2

260

-20

90

5

3

0

-75

0

5

3

Max. Comp 15 20 25 30 20 25 30 35 20 25 30 35 20 25 30 35 20 25 20 25 20 25 30 35 20 25 30 35 20 25 30 35 15 20 25 20 25 30 20 25 30 35

Note: RMAX, RINT, RMIN = long, intermediate and short radii of ellipsoid. Az = azimuth (positive from north) of direction with long radius. Dip = dip (negative from horizontal down) of the direction of the long radius. Spin = third rotation angle around the direction of the longest range (Az/Dip) to put the direction of the short range into place. For example in Domain 2, the 50-metre long search radius of run 1 is along a direction dipping 10° to N270° or west. The 20-metre intermediate search radius is along a direction dipping 80° to east and the 10-metre short search radius is along the horizontal N-S direction. Min. Comp. = minimum number of composites retained in search ellipsoid for kriging of block to proceed. Max. Comp./Hole = maximum composites retained in the same hole. Max. Comp. = maximum number of composites retained in ellipsoid.

4 February 2014

14-15

Mineral Resource Estimates

Table 14-12 Detour Lake Statistics of Block Grade Estimates from the Various Interpolation Runs Domain

Total Blocks

Total Composites

1

60,061

7,777

2

175,092

25,667

3

179,877

16,877

4

196,697

1,896

5

12,106

1,896

6

5,840

2,008

7

52,025

9,817

8

81,584

12,999

9

3,808,835

93,660

10

71,799

640

11

124,373

36,231

12

156,239

2,900

4,924,528

216,436

All Above

14-16

Run 1 2 3 4 All 1 2 3 4 All 1 2 3 4 All 1 2 3 4 All 1 2 All 1 2 All 1 2 3 4 All 1 2 3 4 All 1 2 3 4 All 1 2 3 All 1 2 3 All 1 2 3 4 All

Estimated Blocks 28,067 11,131 5,396 3,404 47,998 108,856 53,770 7,624 2,025 172,275 106,619 46,709 14,300 10,393 178,021 69,959 56,548 31,340 16,543 174,390 10,964 1,141 12,105 4,632 1,208 5,840 29,958 17,290 3,414 1,363 52,025 62,859 17,580 1,012 132 81,583 655,681 520,700 413,086 375,006 1,964,473 5,564 5,937 4,255 15,756 113,636 10,476 244 124,356 33,275 49,983 38,575 17,648 139,481 2,968,303

Min. g/t Au 0 0 0.01 0.01 0 0.01 0.01 0.01 0.02 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.04 0.01 0.02 0.13 0.02 0 0 0 0.21 0 0.01 0.01 0.06 0.15 0.01 0 0 0 0 0 0 0 0 0 0.01 0.06 0.16 0.01 0 0 0 0 0 0

Max. g/t Au 9.78 5.26 2.64 2.97 9.78 8.51 4.56 4.07 2.14 8.51 5.2 3.46 2.49 1.21 5.2 4.44 3.34 2.92 2.78 4.44 2.8 1.35 2.8 6.71 3.28 6.71 8.77 6.99 4.52 2.78 8.77 4.93 3.58 2.24 2.73 4.93 3.46 2.2 1.75 1.64 3.46 3.31 1.62 1.31 3.31 6.65 3.53 1.08 6.65 1.19 1.06 1 0.96 1.19 9.78

Mean g/t Au 1.61 0.75 0.56 0.43 1.21 0.78 0.79 0.71 0.42 0.78 0.62 0.48 0.39 0.32 0.55 0.49 0.49 0.46 0.43 0.48 0.54 0.48 0.53 1.03 1.12 1.05 1.18 0.84 0.87 1.11 1.05 0.7 0.61 0.68 0.51 0.68 0.17 0.13 0.1 0.09 0.13 0.37 0.25 0.18 0.27 0.96 0.61 0.49 0.93 0.04 0.06 0.06 0.05 0.05 0.29

%CV 85 76 86 108 100 80 69 77 82 77 80 73 73 60 81 79 72 73 76 76 67 42 66 79 55 75 88 80 79 48 88 79 59 60 78 76 126 129 137 144 136 131 113 125 132 82 61 28 82 237 216 198 198 214 159

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Figure 14-7 Examples of Panels with Local Orientation of Search Ellipsoids

Note: Az = azimuth (positive from north) of direction with long radius. Dip = dip (negative from horizontal down) of the direction of the long radius. Spin = third rotation angle around the direction of the longest range (Az/Dip) to put the direction of the short range into place. Azimuth varies from N245° (east side) to N280° (west side). Dip varies from 0 to -40°. Spin varies from -75° (dip to south) to + 50° (dip to north).

4 February 2014

14-17

Mineral Resource Estimates

Figure 14-8 Detour Lake 6,198 Bench with Composites and Estimated Block Grades

Block A

Detour Lake

Note: Composites () and blocks ( ) in the 12-metre sections are coloured according to capped Au grade.

14-18

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Figure 14-9 Detour Lake Sections 17,500E and 18,000E with Composites and Estimated Block Grades

Note: Composites () and blocks ( ) in the 10-metre sections are coloured according to capped Au grade.

4 February 2014

14-19

Mineral Resource Estimates

14.2.8 Detour Lake Mine Mineral Resources Classification The classification methodology of 2011 was retained for the update of resources and is described here. Several factors were used in the determination of the mineral resource classification as follows: 

CIM requirements and guidelines;



Experience with similar deposits; and



Spatial continuity of the mineralization.

Resources in any given block are first characterized in an automatic manner, which is then edited manually through solid generation to provide the final classification. The automatic classification of estimated resources in each block uses minimum search conditions for composites around the block. Those conditions are set up in such a way that: 

Blocks recognized by adjacent holes on a nominal 20 x 20 metre grid (or less) on E-W long sections can have their resources in the Measured category;



Blocks recognized by adjacent holes on a nominal 40 x 40 metre grid (or less) on E-W long sections can have their resources in the Indicated category; and



All the other estimated blocks are in the Inferred category.

From previous sensitivity work completed in the pre-feasibility study, search conditions that allow classifying blocks according to those criteria include: 

All composites are used, not just those in the same mineralized domain as that of the block (this is to avoid border effect problems);



E-W vertical flat ellipsoids with a 25 metres long radius for Measured and 50 metres long radius for Indicated; N-S short radius is 5 metres for Measured and 10 metres for Indicated;



Maximum number of composites from the same hole of 1;



Minimum number of composites of 4 for Measured and 3 for Indicated; and



For the Measured category, composites in at least 4 different octants around the block will ensure a good spatial distribution of composites around the block in the ellipsoid.

Figure 14-10 shows an example of automatic and manual classification. The automatic classification has its drawbacks (i.e. a “swiss cheese” or “spotted dog” pattern) with patches of Measured (in red) alternating with patches of Indicated (in yellow) or Inferred (in blue). The final classification (refer to Figure 14-10) uses smoother limits drawn around groups of blocks automatically classified as Measured or Indicated in each bench. In addition, these limits do not change abruptly from one bench to the next, thus defining solids of Measured and Indicated resources with a simple 3D shape.

14-20

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

During the editing exercise, it is important to identify the differences between automatic and final resources classification in the Indicated and Measured categories of each bench and ensure that it does not exceed a few percent. Figure 14-10 Detour Lake Section 17,460E; Automatic and Final Classifications of Blocks

Note: Red drill hole traces indicate drilling or assays added since 2011 resource estimation.

14.2.9 Detour Lake Mine In-Pit Mineral Resources The resources block model was exported to MineSight optimization software and a pit was generated by BBA on Measured and Indicated resources only. The pit optimization uses the Lerch Grossman (LG) 3D algorithm. SGS Geostat used the pit shell generated by BBA and provided by Detour Gold for the Detour Lake mine. Base case pit parameters are listed in Table 14-13. The detailed mineral resource estimation at different CoG for the OK model within the pit shell generated is presented in Table 14-14. Resources are limited on the top by the limit of the overburden as modelled using the drill hole information.

4 February 2014

14-21

Mineral Resource Estimates

Table 14-13 Base Case Pit Optimization Parameters Parameters Gold price

Value

Units

1,200

US$/oz

Exchange rate

1.03

US$/Cdn$

Mining Cost

2.85

$/tonne mined

Milling cost

8.50

$/tonne milled

TMA Cost

1.25

$/tonne milled

G&A cost

2.72

$/tonne milled

Recovery

91.5

%

Royalty *

2

%

Refining and transport Gold payment Minimum profit (1 cent per tonne) Pit Slope Incremetal cost per bench

5.00

$/oz

99.935

%

0.01

$/t

48 0.024

Degrees $/t/bench

* After refining and transport.

14-22

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Table 14-14 Detour Lake Mine Mineral Resources1, 2, 3, 4, 5 Effective December 31, 2013 Category

Measured (M)

Indicated (I)

Total (M&I)

Inferred

Cut-off Grade (g/t Au)

Tonnes (millions)

Grade (g/t Au)

Contained Gold Ounces (000's)

0.3

21.1

1.15

784

0.4

18.6

1.27

755

0.5

16.4

1.37

725

0.6

14.6

1.48

691

0.7

13.0

1.58

658

0.3

102.7

0.79

2,611

0.4

81.8

0.90

2,377

0.5

65.9

1.01

2,150

0.6

53.4

1.12

1,929

0.7

43.1

1.24

1,714

0.3

123.8

0.85

3,394

0.4

100.3

0.97

3,132

0.5

82.4

1.09

2,874

0.6

67.9

1.20

2,620

0.7

56.0

1.32

2,372

0.3

47.0

0.53

807

0.4

29.3

0.65

610

0.5

19.2

0.75

465

0.6

12.5

0.86

348

0.7

8.3

0.98

260

1

CIM definitions were followed for mineral resources. 2 Base case CoG used for Detour Lake mine is 0.5 g/t Au. 3 Mineral resources were calculated using a gold price of US$1,200/oz. 4 Mineral resources are exclusive of mineral reserves. Mineral resources that are not mineral reserves do not have demonstrated economic viability. 5 Capping grades estimated by domains and vary from 15 m. g/t to 50 m. g/t Au.

14.3 Block A Resource Estimate 14.3.1 Block A Data The MRE of the Block A gold deposit was completed using the data from the historic drilling, Trade Winds drilling campaign from 2003 to 2011 and Detour Gold’s drilling from 2008 to 2012. Sample data used in the construction of the proposed resource model was in a drill hole database received from Detour Gold on June 7, 2013. Table 14-15 summarizes the records in the database used for this MRE.

4 February 2014

14-23

Mineral Resource Estimates

Table 14-15 Block A Database Summary Drill Hole Data Source 1

Number of Drill Holes Surface Holes

2

UG Holes

Total

Length (m)

Nb. of Survey

Nb. of Lithology

Nb. of Assay

Historical (PD & PM )

151

207

358

111,924

2,657

21,231

92,034

Trade Winds (TW)

350

0

350

122,054

39,368

16,179

134,514

Detour Gold (DG, DBKA)

276

0

276

118,894

3,816

4,764

121,920

Total

777

207

984

352,872

45,841

42,174

348,468

1

PD: Placer Dome; PM: Pelangio Mines. 2 UG: Underground.

Detour Gold’s drilling (DG, DGE and DBKA series), from 2008 to 2012, accounts for 276 surface holes totalling 118,894 metres. The DG, DGE and DBKA series surface holes are generally dipping 50° to the south on N-S cross-sections at 40 metres spacing and with the same 40 metres vertical spacing between holes on the same section. In a few specific sectors, that horizontal/vertical spacing is reduced to 20 metres. With a total 121,920 assay intervals being from DG and DBKA holes, they comprise about 35% of the assay information. 14.3.2 Block A Geological Interpretation In 2012 and 2013, the Detour Gold geology department and Thon Consulting updated the wireframe model using Datamine 3D modeling software, based on the drilling database available at the time. In 2013, updated wireframes for Domains 1 to 4, 8, 10 and 13, 14 and 9 were sent to SGS Geostat. On October 25, 2013, updated wireframes together with the outer shell, topography and overburden surfaces were received as DXF files for all domains from Detour Gold, with the following details: 

DXF files for open surfaces: topography surface + overburden/bedrock contact surface;



Old underground openings for Block A (not DXF files);



DXF files for mineralized domain solids i.e. 01, 02, 03, 04, 08, 10, 13, 14 and 09 (outer shell); and



DXF files for mostly barren intrusive structures (not used for the MRE).

In order to design the mineralized domain solids, Detour Gold’s geologists have interpreted limits of mineralized domains on sections and benches. Those domains correspond to broad zones with a higher than usual concentration of samples with potentially economic gold grades. Domain 1 corresponds to the CMH which crosses a portion of the Detour Lake deposit from east to west with a well-defined flexure on the east side of the deposit. All the others mineralized domains are built around Domain 1. The provided mineralized solids and drill hole samples cover a 3,100 x 2,200 metre area from sections 14,500E/19,100N to 17,600E/21,300N. The bottom of the interpretation is at Z=5,300EL while the topographic surface rarely exceeds Z=6,300EL hence a 1,000 metre vertical span. An overlapping area between sections 16,500E and 17,600E is present between Block A and Detour Lake mine models. The presence of this buffer was 14-24

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

for the added information for geological modeling, grade continuity, geostatistical analysis and resources estimation purposes. Drill hole samples are mostly north of the mineralized Domain 1 (CMH), a narrow corridor about 10 metres wide. Other mineralized domains are E-W elongated and sub-vertical dips: to the north, from the CMH, are Domains 8, 11, 2, 3, then Domains 4, 5 and a new marker zone identified as Domain 10, which is mostly recognized on the western extension of the Detour Lake deposit. Domains 6 and 7 are south of the CMH, mostly on the east side, and on both sides of an ultramafic intrusive (Domain 12). Additional domains mostly outlined by Trade Winds drilling were added to the north of Domain 10. All potentially mineralized material left between non-specific domains is included in an outside shell, labeled as Domain 9. 14.3.3 Block A Capping Most of the gold values present in the database are of lower grade, but some results returned anomalously high gold values. Anomalous values were capped before block grade interpolation. A standard approach to capping high-grade gold values consisted of developing the probability plots and examining the distribution to search for any natural gap in those distributions. As illustrated in Table 14-16, the very high-grade intervals (outliers) may have different lengths (from 0.25 metres to 1.52 metres for the 51 intervals with a grade above 300 g/t Au). To accurately compare the anomalous high gold assay values (high gold grade is more likely to occur in a short interval), SGS Geostat looked at distributions of GT Products for better results.

4 February 2014

14-25

Mineral Resource Estimates

Table 14-16 Block A Drill Hole Assay Intervals with Gold Values above 300 g/t From

To

Length

Au

(m)

(m)

(m)

(g/t)

DBKA12-0074

676.50

677.00

0.50

1,940.00

4

38-046

238.97

239.27

0.30

1,814.00

11

DG-07-044

224.50

225.00

0.50

1,433.76

8

TWDDH-323

152.00

152.55

0.55

1,050.00

14

TWDDH-143

108.75

109.25

0.50

1,010.00

9

TWDDH-162

TWDDH-143

108.75

109.25

0.50

973.022

9

DG-08-351

DG-08-351

378.00

379.00

1.00

848.95

9

PMDDH-080

DG-07-140

135.90

136.40

0.50

782.84

11

439-008

823.00

8240

1.00

760.41

9

TWDDH-180

285.38

285.88

0.50

705.85

14

DG-08-540

470.60

471.10

0.50

704.8

11

161

162.00

1.00

680.4

2

Hole

07-0585

Domain

From

To

Length

Au

(m)

(m)

(m)

(g/t)

11-0974

192.00

193.00

1.00

427.00

11

DG12-1207

259.00

259.50

0.50

422.67

3

07-0035

103.00

104.00

1.00

412.50

7

DG-08-530

113.00

113.50

0.50

411.51

11

37.45

38.00

0.55

410.22

4

177.00

178.00

1.00

397.28

3

43.80

44.30

0.50

389.95

11

188.00

189.00

1.00

385.44

2

81.86

82.36

0.50

378.09

10

259.50

260.00

0.50

377.71

2

Hole

DG-07-270 TWDDH-197 DG-07-117

Domain

DG-08-302

96.50

97.00

0.50

376.38

2

TWDDH-065

38.00

38.50

0.50

367.00

4

38-046

221.84

222.14

0.30

591.8

11

38-003

98.15

98.45

0.30

366.20

11

DBKA12-0103

665.80

666.80

1.00

587.51

4

15-0761

13.00

14.00

1.00

350.50

9

TWDDH-041

61.70

62.00

0.30

580.84

9

DG-08-353

586.00

586.50

0.50

338.02

2

PMDDH-104

112.50

113.00

0.50

574.15

11

DG-07-077

278.70

279.20

0.50

334.86

2

56.50

57.00

0.50

572.15

11

11-0794

11.00

12.00

1.00

3240

11

DG-07-108 DG-08-369

459.00

459.50

0.50

565.55

2

DG-07-018

327.50

328.00

0.50

322.09

11

DG10-0892

354.50

355.00

0.50

551.70

3

DG-07-234

306.20

306.70

0.50

320.51

8

DG-09-618

146.50

147.00

0.50

536.06

2

DG-07-117

260.00

260.50

0.50

313.92

2

PMDDH-077

207.40

207.90

0.50

488.66

11

11-0052

143.00

144.00

1.00

312.50

11

2.00

3.00

1.00

481.23

9

38U-063

13.72

15.24

1.52

308.60

1

TWDDH-053

244.70

244.95

0.25

475.30

10

DG-07-118

64.00

64.50

0.50

305.98

11

DG-07-016

296.80

297.30

0.50

461.64

11

DG-08-473B

249.00

249.50

0.50

305.66

2

11-0540

103.00

104.00

1.00

300.00

2

15-0715

DG10-0886

67.50

68.00

0.50

449.65

9

DG-08-606A

623.00

624.00

1.00

449.51

2

For the 2013 Block A mineral resource update, the capping statistics presented in Table 14-17 show that few high-grade values need to be capped inside the Domain 9 but they represent an important amount of the total metal content. Distributions of GT Products for original assay intervals have been examined for each of the mineralized domains (examples in Table 14-17 and Figure 14-11). GT Products distributions are limited to drill hole assay intervals with a GT Product over 0.3 m. g/t Au (0.3 g/t Au over one metre), which is close to the limit for “mineralized” samples. Sensitivity analysis shows that the shape of cumulative frequency plots for high GT Product data changes very little when the lower limit varies from 0.2 to 0.5 m. g/t Au.

14-26

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Table 14-17 Block A Capping Limits for GTs of Original Sample Data Domain

Nb. GT

Avg. GT m.g/t

Cap1

Capping (m.g/t)

Nb. Capped

% Capped

Cap2

Avg. GT (m.g/t)

% GT Lost

Nb. Capped

% Capped

Avg. GT Lost

% GT Lost

1

1,830

0.46

50

NA

NA

0.46

NA

NA

NA

NA

NA

2

14,672

0.94

30

47

0.32

0.87

7.6

NA

NA

NA

NA

3

17,436

0.62

25

35

0.20

0.58

7.3

NA

NA

NA

NA

4

43,184

0.53

25

56

0.13

0.46

13.9

NA

NA

NA

NA

8

3,379

0.67

30

6

0.18

0.62

7.4

NA

NA

NA

NA

10

22,003

0.79

75

18

0.08

0.71

9.1

NA

NA

NA

NA

13

5,248

0.52

15

22

0.42

0.48

7.0

NA

NA

NA

NA

14

8,345

0.68

40

9

0.11

0.59

13.0

NA

NA

NA

NA

Subtotal Above

116,097

0.66

NA

193

0.17

0.59

10.1

NA

NA

NA

NA

Outside (0)

25,086

0.20

15

203

0.17

0.17

17.1

NA

NA

NA

NA

9

207,285

0.19

15/30

11

0.10

0.17

10.5

71

0.03

0.18

6.0

Total

348,468

0.35

NA

439

0.13

0.31

10.5

307

0.09

0.32

9.0

Figure 14-11 Examples of Block A GT Cumulative Frequency Plots in Mineralized Domains Detour Gold- Block A- 2013- Domain A10- GT>0.3 1000 GT

"

Detour Gold- Block A- 2013- Domain A14- GT>0.3 1000 GT

"

"

"" " "

100 "" """" """

" " " """

100

""

" " " "

10

"" "" """ """ """" """" " "" """" """"" """""" """"" """"" """"""" """"""" """""" "" "" """""""

1 50

70

80

""

" ""

""

""

""

"

"

""

"

"

"

"

"

"

"

10

Cumulative Freq [%] 90

95

98

99

99.8

99.99

1

""" """ """ """ """"" """" "" "" """"" """" """"" """"""" """"" """"" """""" """ "" "" """"""" """""" """""" """""" """""""

50

70

80

""

""

90

""

"

""

""

"""

"

" " "

"

"

"

"

"" """""

"

""

"""

" "" "

"

" " "

"

"

"

Cumulative Freq [%] 95

98

99

99.8

99.99

For most domains, the cumulative frequency plots for high GT Products on a log scale do not show any obvious abrupt change of slope, which, if present, would correspond to a natural gap in the data. As a result, it can be concluded that the selected cap limits are fairly subjective. As such, upper limits for capping are chosen to correspond to the same percentage of lost gold in each of the mineralized domains. The final selection is based on average grade of all composites in each domain with the highest cap of 75 m. g/t (75 g/t over 1 metre) in Domain 10, with the highest average GT of about 0.79 m. g/t. In the background domain (Domain 9), the capping has two different values, a high capping value of 30 m. g/t for short range estimate, and a low capping 4 February 2014

14-27

Mineral Resource Estimates

value of 15 m. g/t for longer range estimate. The overall gold lost to capping amounts to 9%, which is comparable to Detour Lake mine levels as stated in the MRE in the feasibility study (BBA, 2010). Table 14-17 shows the effect of those capping limits on the statistics of gold values. 14.3.4 Block A Composites The analysis of the spatial continuity of gold grade in each specific mineralized domain was done on the capped grade of the 5 metres down-hole composites. The composite size is selected to match the 5 metre N-S thickness of the 10 x 5 x 6-metres resource blocks. The intent of selecting composites with length similar to the mineralized block intercepts is to ensure that grade dilution originating from the block size will be included in the grade of samples used for interpolation. Individual assays are capped prior to compositing. Table 14-18 lists some statistics of the computed grade for the 5 metres composites in all domains. Only composites of at least half the nominal composite length (thus 2.5 metres) are used for the estimate. Comparison of the composited grades within the Detour Gold holes versus historical drill holes showed relevant discrepancies. By assigning a default grade of 0.01 g/t Au to all missing assay values within the historical drill holes (referred to as padding), these discrepancies were diminished. The routine of padding with "dummy intervals" of near zero grade values was implemented before the compositing. Compositing starts at the overburden-bedrock contact. Statistical data in Table 14-18 indicates the coefficient of variation (CV) values in the range of 150% or higher. Table 14-18 Block A Statistics of Uncapped and Capped Composite Data (5 m) Totaled by Domain Domain

Number Composites

Min. (g/t Au)

Median (g/t Au)

Max. Uncap (g/t Au)

Max. Cap (g/t Au)

Avg. Uncap (g/t Au)

1

351

0.002

0.09

7.04

7.04

0.47

2

2,822

0.003

0.38

22.96

14.12

3

3,488

0.003

0.24

26.34

12.35

4

8,088

0

0.21

194.19

8

652

0.003

0.18

20.57

9

42,466

0

0.05

10

4,186

0.003

13

1,129

0.01

14

1,599

All

65,501

Avg. Cap (g/t Au)

Coeff. Var. Uncap (%)

Coeff. Var. Cap (%)

0.47

2.06

0.99

.91

1.93

160

0.62

0.57

231

178

14.49

0.52

0.45

534

171

9.97

0.70

.64

231

193

152.53

7.39

0.19

0.17

528

237

0.26

98.94

27.62

0.82

0.75

356

238

0.20

12.32

6.78

0.48

0.45

202

165

0.003

0.18

115.60

10.98

0.71

0.61

459

196

0

0.08

194.19

27.62

0.35

0.32

475

253

Examples of histograms of composite grades are shown in Figure 14-12. All distributions show a peak at 0.1 g/t Au corresponding to low-grade default values from old drill holes. Additionally the 0.01 g/t Au grades correspond to padded intervals. Moving from wellmineralized domains (1, 2, 8, 13 and 14) into lower grade domains (3, 4, 9 and 10), the proportion of composites with values within the 0.01 to 0.10 g/t Au range is increasing. A 14-28

4 February 2014

2.06

Detour Lake Mine NI 43-101 Technical Report

negative skewness of values above the default is observed within the higher grade domains while a positive skewness of the data is observed in the lower grade domains. Figure 14-12 Examples of Block A Histograms of 5 metre Composite Grades per Domain 7 .00

Detour Gold BLock A 5m composites in Domain 10

5. 69

Rel ative Fre q

6 .30

5. 12

5 .60

4. 55

4 .90

3. 98

4 .20

3. 41

3 .50

2. 85

2 .80

2. 28

2 .10

1. 71

1 .40

1. 14

0 .70

0. 57

Au

0 .00 0.003

0 .008

0. 024

0.0 68

0.1 92

0.545

1 .542

4. 364

12. 351

34. 957

98.9 36

Detour Gold BLock A 5m composites in Domain 14 Rela tive Freq

Au

0. 00 0 .003

0. 009

0.0 25

0.07 1

0 .205

0. 589

1.69 3

4.866

13 .989

40. 213

115. 597

14.3.5 Block A Spatial Analysis Spatial continuity of the composite grades in each domain is assessed through correlograms (the calculated correlation coefficient of grades from pairs of composites separated by a given distance in a given direction). Examples of the experimental correlograms are presented as variograms (Figure 14-13). Directions investigated are the E-W horizontal average strike, the vertical average dip and the horizontal N-S across average strike and dip as well as two intermediate directions in E-W vertical planes dipping 45° to west and 45° to east. In each case, in addition to the principal directions, the average downhole correlogram (along drill holes) is calculated in order to better assess the magnitude of the nugget effect. Results of variogram models (refer to Table 14-19) show that for most domains, the spatial continuity of the grade of composites is characterized by: 

A significant relative nugget effect from 50% to 70%;



A generally well-defined anisotropy with best continuity (lowest curve) along the average E-W horizontal strike (dip to west);



Poorest continuity (highest curve) across dip and strike; and



Intermediate continuity along the average vertical dip (dip to east) (refer to Figure 14-13 and Table 14-19).

4 February 2014

14-29

Mineral Resource Estimates

Table 14-19 Block A Variogram Models of 5 metre Composites per Mineralized Domains Variograms Domain

Nugget Panel

Exp2

Sill

Range 1

Range 2

Range 3

Azim

Dip

Spin

0.6

0.2

15 m

10 m

5m

297°

-42°

65°

1

0.7

0.3

40 m

15 m

6m

278°

-10°

-77°

2

"

"

"

"

"

285°

-9°

62°

1

0.65

0.35

30 m

20 m

10 m

283°

-20°

81°

2

"

"

"

"

"

276°

-20°

-79°

3

"

"

"

"

"

285°

-19°

74°

4

"

"

"

"

"

294°

-13°

41°

0.7

0.1

5m

5m

3m

280°

0°

3

"

"

"

"

"

280°

0°

1

0.7

0.3

50 m

25 m

10 m

278°

-9°

64°

2

"

"

"

"

"

275°

-10°

86°

3

"

"

"

"

"

272°

-10°

-81°

9

0.65

0.2

15 m

15 m

5m

270°

-10°

10

0.7

0.2

10 m

3m

3m

281°

13

0.65

0.35

40 m

20 m

4.5 m

14

0.5

0.2

55 m

4m

4.0 m

1 2

3

4

1 and 2

8

Sill

Exp1 Sill

Range 1

Range 2

Range 3

0.2

50 m

30 m

5m

80°

0.2

50 m

25 m

15 m

-84°

"

"

"

"

68°

0.15

150 m

70 m

25 m

-18°

67°

0.1

40 m

25 m

5m

273°

-18°

67°

281°

-33°

66°

0.3

55 m

15 m

10 m

Note: Each model is the sum of a nugget effect and up to two exponential component functions. The sill of the exponential function is also for each domain. The range in metres of the function represents the principal direction (range: long axis; range 2: medium axis and, range 3: short axis). Az/Dip are the azimuth (positive from north) and dip (negative downward) of the direction with the longest range. For example, in Domain 1, the long range is along a direction dipping 42° to west and “Spin” is the third rotation angle around the direction of the longest range (Az/Dip) to put the direction of the short range into place. For example in Domain 1, the 65° spin puts the direction of short range along the horizontal N-S.

14-30

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Figure 14-13 Examples of Block A Correlograms of 5 metre Capped Grade Composites per Mineralized Domains 1.100

Detour Gold- Block A - 2013 - 5m composites in A10 ABS,AuCut !

!

!

SILL

!

!

! !

! !

!

!

!

! !

! !

! ! !

!

!

0.950

Detour Gold- block A - 2013 - 5m composites in A14 ABS,AuCut

1.130

! !

1.000

1.200

!

1.050

!

!

!

!

!

!

! ! !

!

!

!

!

!

!

! !

! !

1.060

!

!

!

!

0.990

! ! !

!

!

! !

!

0.900

0.920

0.850

0.850

0.800

0.780

0.750

0.710

0.700

0.640

!

!

!

!

!

!

!

SILL

!

! !

!!

!

! !

!

!

!

!

!

!

!

! !

!

!

!! !

!

! !

! !

! !

! !

!

!!

! !

!

!

!!

!

!

!

!

!

! !

0.570

0.650 Distance

0.600 0.0

10.0

20.0

30.0

40.0

Variable : AuCut Variogram : Absolute Direction Azimuth Dip Tolerance Lag Dist

!

: Ave : 0.00 : 0.00 :180.00 : 5.10

!

EW 93.00 0.00 20.00 21.00

50.0

Date File !

!

NS Vertical 3.00 3.00 12.00 -68.00 45.00 20.00 5.10 21.00

!

dipE 72.00 -41.00 20.00 25.00

60.0

70.0

80.0

90.0

100.0

: 07-11-2013 : A10cmp5m-RevDir.gsd !

dipW 294.00 -41.00 20.00 25.00

Gamma = N(0.7000) + E(0.2000, 10.0/3.0/3.0, 281.0/-18.0/67.0) + E(0.1000, 40.0/25.0/5.0, 281.0/-

Distance

!

!

0.500 0.0

15.0

30.0

45.0

60.0

Variable : AuCut Variogram : Absolute Direction Azimuth Dip Tolerance Lag Dist

!

: Ave : 0.00 : 0.00 :180.00 : 5.10

!

EW 88.00 0.00 20.00 21.00

75.0

Date File !

!

NS Vertical 358.00 358.00 20.00 -70.00 45.00 20.00 5.10 21.00

!

dipE 69.00 -42.00 20.00 25.00

90.0

105.0

120.0

135.0

150.0

: 07-11-2013 : A14cmp5m-RevDir.gsd !

dipW 287.00 -42.00 20.00 25.00

Gamma = N(0.5000) + E(0.2000, 55.0/4.0/4.0, 281.0/-33.0/66.0) + E(0.3000, 55.0/15.0/10.0, 281.0/

Note: Correlograms are presented as variograms (graph is “1-correlogram”). They are computed along E-W (red), N-S (green), vertical (blue), dip 45° to west (beige) and dip 45° to east (brown). For each direction, the experimental graph and fitted model are shown. An average correlogram (black) is also presented. Note that the vertical scale is generally from 0.5 (not zero) to 1.2. Calculation parameters for each direction and the equation of the fitted model are given in the legend box at the bottom of each plot.

14.3.6 Block A Resource Block Modeling Drill hole spacing across the Block A deposit is generally on the order of 40 metres in the N-S and E-W direction. A block size of 10 x 5 x 6 metres was selected to accommodate the drill hole spacing and width of the mineralization. The 10-metre E-W dimension corresponds to approximately half the minimum spacing between Detour Gold surface holes. The 5 metre N-S dimension accounts for the perceived greater grade variability along that direction while the 6 metres vertical dimension corresponds to half of the bench height of neighboring Detour Lake mine for block model compatibility. Given a density of 2.9 t/m3, each full block 10 x 5 x 6 metres weighs about 870 tonnes and it is a reasonable assumption for the selection mining unit or minimum size block which can be selectively extracted as ore or waste in the future open pit operation. Table 14-20 summarizes the block limit co-ordinates for the Block A block model. All blocks completely above the overburden/bedrock contact surface or outside mineralized Domains 1 to 12 are eliminated, reducing the actual final number of blocks. All data (DDH, composites, domain volumes, geological interpretations) present in the overlapping zone between models was used for resources estimation purposes. Only block edges falling entirely within the Table 14-20 were retained in the MREs.

4 February 2014

14-31

Mineral Resource Estimates

Table 14-20 Block A Resource Block Model Parameters (edges) Coordinate

Number of Blocks

Size of Blocks (m)

Minimum (m)

Maximum (m)

249

10

14,505

16,695

Northing

460

5

19,102.5

21,402.5

Elevation

169

6

5,298

6,312

Easting

There is an exploration ramp totaling 1,300 metres between elevation 5,630 and 5,510EL. The ramp connects to the prior underground operation at the Detour Lake mine. Presently 119 blocks fall inside the ramp volume and were taken out of the resources block model. Figure 14-14 and Figure 14-15 illustrate the block assignment to domains on a few benches and sections. Figure 14-14 Block A Bench 6,189 with Blocks in Mineralized Domains

14-32

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Figure 14-15 Block A Section with Blocks in Mineralized Domains

14.3.7 Block A Block Grade Interpolation The interpolation of the Block A resource model was completed using ordinary kriging (OK) methodology. Search volume dimensions are defined from the variogram models. Limits are set for the minimum and maximum number of samples (composites) used per estimate and as a restriction on the maximum number of samples used from each hole. The estimation was designed as a four-pass system and outlined in Table 14-21. In the first pass, the search ellipse distance was generally 50 metres (X) by 20-30 metres (Y) by 10-15 metres (Z), a minimum of five composites was required and a maximum of 15-20 composites were allowed, with a maximum of three composites from any one hole, which implies a minimum of two holes required in order to estimate a block. The search distance in the second pass was two times the search distance of the first pass. For the third pass, the search distance was three times that of the first pass. A fourth pass was used where required in order to estimate areas with missing blocks for the Inferred resources. The search distance used for this last pass was four times of the first run, using the same anisotropy. The maximum number of composites increases by five from pass to pass. Some domains required several dip and dip directions were used. A “panel” approach was used to set local orientation. The panels were limited by ranges of easting and elevation. The list of panels and the interpolation settings of different passes are detailed in Table 14-21. The majority of the blocks are interpolated in the first pass with the more constrained search conditions with the exception of Domain 9, which represents the background of the model. The estimation of block grades is illustrated on a few benches 4 February 2014

14-33

Mineral Resource Estimates

and sections (Figure 14-16 and Figure 14-17). Statistics for the interpolation of Block A deposit are summarized in Table 14-22. Table 14-21 Block A Block Model Estimation Parameters Domain

14-34

Panel

1

NA

2

1

2

2

3

1

3

2

3

3

3

4

4

1 and 2

4

3

9

NA

10

NA

13

NA

14

NA

Pass 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4

Rmax (m) 50 100 150 200 50 100 150 200 50 100 150 200 50 100 150 200 50 100 150 200 50 100 150 200 50 100 150 200 50 100 150 200 50 100 150 200 50 100 150 200 50 100 150 200 50 100 150 200 50 100 150 200

Rint (m) 30 60 90 120 20 40 60 80 20 40 60 80 30 60 90 120 30 60 90 120 30 60 90 120 30 60 90 120 25 50 75 100 25 50 75 100 30 60 90 120 20 40 60 80 25 50 75 100 20 40 60 80

Rmin (m) 15 30 45 60 10 20 30 40 10 20 30 40 10 20 30 40 10 20 30 40 10 20 30 40 10 20 30 40 15 30 45 60 15 30 45 60 15 30 45 60 10 20 30 40 10 20 30 40 10 20 30 40

Azi (deg)

Dip (deg)

Spin (deg)

Min. Comp.

Max Cmp. Per hole

297

-42

65

5

3

278

-10

-77

5

3

285

-9

62

5

3

283

-20

81

5

3

276

-20

-79

5

3

285

-19

74

5

3

294

-13

41

5

3

280

0

80

5

3

280

0

-84

5

3

270

-10

68

5

3

281

-18

67

5

3

273

-18

67

5

3

281

-33

66

5

3

Max Comp. 15 20 25 30 20 25 30 35 20 25 30 35 20 25 30 35 20 25 30 35 20 25 30 35 20 25 30 35 20 25 30 35 20 25 30 35 20 25 30 35 20 25 30 35 20 25 30 35 20 25 30 35

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Table 14-22 Block A Statistics of Block Grade Estimates from the Various Interpolation Runs Domain

Total Blocks

Total Composites

1

14,345

351

2

60,945

2,822

3

34,356

3,488

4

336,452

8,088

9

5,040,106

42,466

10

127,482

4,186

13

80,911

1,129

14

44,739

1,599

5,739,336

64,129

All Above

4 February 2014

Estimated Blocks

Min. g/t Au

Max. g/t Au

Mean g/t Au

%CV

1 2 3 4 All 1 2 3 4 All 1 2 3 4 All 1 2 3 4

415 2,492 3,033 2,531 8,471 15,350 28,789 10,049 3,426 57,614 11,364 9,124 7,231 5,120 32,839 86,742 107,165 50,293 38,496

0.01 0.01 0.01 0.01 0.01 0.03 0.02 0.02 0.02 0.02 0.01 0.01 0.02 0.02 0.01 0.00 0.01 0.02 0.02

2.09 1.76 1.65 1.44 2.09 6.04 3.99 2.63 1.96 6.04 1.63 1.92 1.54 1.06 1.92 6.10 5.94 5.46 5.45

0.40 0.23 0.27 0.20 0.24 1.05 0.82 0.59 0.48 0.82 0.23 0.31 0.34 0.31 0.29 0.41 0.49 0.54 0.52

111 144 125 116 130 74 66 72 75 75 73 77 65 54 72 78 72 82 90

All 1 2 3 4 All 1 2 3 4 All 1 2 3 4 All 1 2 3 4 All

282,696

0.00

6.10

0.48

80

459,028 1,035,886 949,058 793,462 3,237,434 45,499 59,606 17,223 4,218 126,546 13,215 30,542 12,514 8,342 64,613 18,063 20,610 3,813 1,729 44,215

0.00 0.00 0.00 0.00 0.00 0.02 0.03 0.04 0.05 0.02 0.01 0.01 0.01 0.01 0.01 0.01 0.03 0.11 0.09 0.01

3.17 2.20 2.29 1.94 3.17 7.23 4.36 3.17 3.10 7.23 3.07 2.54 2.55 1.84 3.07 3.99 3.66 3.88 3.34 3.99

0.19 0.14 0.15 0.16 0.15 0.80 0.76 0.78 0.87 0.78 0.48 0.46 0.43 0.43 0.45 0.62 0.68 0.99 1.08 0.70

118 122 133 131 127 102 72 64 66 84 84 71 74 75 75 93 72 59 54 79

3,854,428

0.00

7.23

-

-

Run

14-35

Mineral Resource Estimates

Figure 14-16 Block A Bench 6,189 with Composites and Estimated Block Grades

Block A

14-36

Detour Lake

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Figure 14-17 Block A Sections with Composites and Estimated Block Grades

14.3.8 Block A Mineral Resource Classification The mineral resources of Block A have all been classified as Measured, Indicated and Inferred categories as defined by NI 43-101 standards and CIM definitions. The parameters used to determine the mineral resource classification are the composites and drilling density. An automatic classification algorithm has been used. Effectively, if at least three drill holes are at less than 18 metres from each other, then the surrounding material is considered as Measured. If at least two drill holes are at less than 45 metres from each other, then the surrounding material is considered as indicated. Since the drill grid in Block A is mostly 40 metres, a large part of the estimated blocks are considered Indicated. Resources supported by only one hole or with a larger drill grid are considered Inferred. Undrilled extensions along strike and down dip are interpreted as Inferred resource as far as about 100 metres from drill hole information. Figure 14-18 and Figure 14-19 show some plan views and section views of the block model with composites.

4 February 2014

14-37

Mineral Resource Estimates

Figure 14-18 Block A Bench 6,189 with Automatic Resource Classification

Figure 14-19 Block A Sections 15,900 and 16,270 with Automatic Resource Classification

14-38

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

14.3.9 Block A In-Pit Mineral Resources The resources block model was exported to MineSight optimization software and a pit was generated by BBA on Measured and Indicated resources only. The pit optimization uses the Lerch Grossman (LG) 3D algorithm. SGS Geostat used the pit shell generated by BBA and provided by Detour Gold for Block A. Base case pit parameters are listed in Table 14-13. The detailed mineral resource estimation at different CoG for the OK model within the pit shell generated is presented in Table 14-23. Mineral resources are limited on the top by the limit of the overburden as modelled using the drill hole information. Table 14-23 Block A Mineral Resources1, 2, 3, 4, 5 Effective December 31, 2013 Category

Measured (M)

Indicated (I)

Total (M&I)

Inferred

Cut-off Grade (g/t Au)

Tonnes (millions)

Grade (g/t Au)

Contained Gold Ounces (000's)

0.4

2.5

0.91

74

0.5

1.9

1.05

65

0.6

1.5

1.21

57

0.7

1.1

1.37

50

0.8

1.0

1.49

46

0.4

86.6

0.89

2,472

0.5

66.9

1.02

2,189

0.6

52.5

1.15

1,934

0.7

41.5

1.28

1,705

0.8

33.3

1.41

1,509

0.4

89.1

0.89

2,546

0.5

68.9

1.02

2,254

0.6

53.9

1.15

1,991

0.7

42.6

1.28

1,756

0.8

34.3

1.41

1,555

0.4

4.0

0.95

123

0.5

3.2

1.09

111

0.6

2.5

1.23

99

0.7

2.0

1.38

88

0.8

1.6

1.54

79

1

CIM definitions were followed for mineral resources. 2 Base case CoG used for Block A deposit is 0.6 g/t Au. 3 Mineral resources were calculated using a gold price of US$1,200/oz. 4 Mineral resources are exclusive of mineral reserves. Mineral resources that are not mineral reserves do not have demonstrated economic viability. 5 Capping grades estimated by domains and vary from 15 m. g/t to 75 m. g/t Au.

4 February 2014

14-39

Detour Lake Mine NI 43-101 Technical Report

15.0 Mineral Reserve Estimates For the mineral reserve estimation, the resource block model was provided by SGS Geostat and was transferred into the MineSight software and an economic model was prepared for the pit optimization. The pit optimization uses the Lerchs-Grossman 3D (LG 3D) algorithm in MineSight. The general overall pit slopes used in the pit optimization were 50° in the hangingwall (north wall) and 48° for the footwall (south wall). The mineral reserves were estimated through an open pit optimization exercise using the Measured and Indicated category resources in the block model, followed by a detailed engineered design to include all aspects of a final pit (main haul road, geotechnical berms, etc.). The mineral reserves inside the engineered pit design were estimated using a CoG 0.5 g/t Au, based on a gold price of US$1,000/oz. The Proven and Probable mineral reserve totals 474.0 Mt at 1.02 g/t Au for 15.6 million ounces of contained gold. An inventory of 2.4 Mt of ore grading 0.82 g/t Au is also stockpiled as of December 31, 2013. Total waste, including Inferred resources, backfilled stopes, overburden and waste rock, is 1.68 billion tonnes, resulting in a waste to ore ratio of 3.54 to 1. The pit stripping ratio excludes current ore on stockpile. No additional dilution was added during the pit shell optimization since an inherent grade dilution of 11.7% is included in the OK block model (as described in detail in BBA, 2011). The mineral reserve estimate inside the detailed engineered pit design includes an additional mining dilution estimated at 4.0% at a grade of 0.20 g/t Au, resulting in a global dilution of 15.7%. For 2014, as Detour Gold continues to expand the pit, mining dilution is estimated at 7.0% (at a grade of 0.20 g/t Au). The mining loss is estimated at 5%. The mineral reserves for the Detour Lake mine are presented in Table 15-1. Table 15-1

Detour Lake Mine Mineral Reserves1, 2, 3, 4, 5 Effective December 31, 2013

Category

Tonnes (millions)

Grade (g/t Au)

Contained Gold Ounces (000's)

Proven Probable

94.4 379.7

1.29 0.95

3,901 11,585

Proven + Probable

474.0

1.02

15,486

2.4

0.82

63

476.4

1.02

15,549

Stockpiles Total 1

CIM definitions were followed for mineral reserves. 2 Mineral reserves are estimated using a gold price of US$1,000/oz. 3 Mineral reserves are based on a cut-off grade of 0.5 g/t Au. 4 Reserves include ore loss of 5% and dilution of 4% at 0.20 g/t Au (7% at 0.20 g/t for 2014). 5 Totals may not add due to rounding.

4 February 2014

15-1

Mineral Reserve Estimates

15.1 Reserve Block Model The mining engineering work related to pit optimization and engineered pit design was carried out using the block model prepared by SGS Geostat in September 2013. The model was transferred into the MineSight software package used by BBA for mining studies. The model was rigorously checked, including a review of the block grades and domains on plans and sections to ensure the integrity of the transfer. The block size for the model is 10 x 5 x 12 metres. SGS Geostat provided the following data in the block model: 

Gold grade;



Ore category (Measured, Indicated and Inferred);



Density;



Domain;



Volume below topography; and



Material volumes (rock, overburden, fill material in previous underground workings and stopes).

15.2 Pit Optimization The development of the engineered ultimate pit design for the Detour Lake mine was carried out in two consecutive steps as follows: 

Step 1: Determination of the economic pit shell using the LG 3D true pit optimizer, based on operating costs and revenue data along with pit slope requirements; and



Step 2: Preparation of the engineered pit design by incorporating in the pit shell the final ramp and proper pit slope, as well as the benching arrangement.

The pit optimization process uses the LG 3D algorithm in MineSight and is considered as the standard routine in the industry. The LG 3D is a true pit optimizer, which uses the dynamic programming of the graph theory to generate an optimal economic pit shell from a 3D block model. The basic optimization principle of the algorithm operates on a net value calculation for the ore block in the model, i.e. revenue from sales less total operating costs. The combination of these values and slope requirements allow the optimizer to search for the pit shell with the highest undiscounted cash flow. In the block model, all blocks classified as a mineral resource (Measured, Indicated and Inferred) are given a grade value. In accordance with the guidelines of NI 43-101 and the Canadian Institute of Mine Metallurgy and Petroleum definition Standards for Mineral Resources and Mineral Reserves, only blocks classified as either Measured or Indicated are allowed to drive the pit optimizer for an existing operation.

15-2

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

15.2.1 Grade Data The gold grade data was provided in the mineral resource block model and is the main item used for pit optimization and mineral reserve estimate. The gold grade of each block was adjusted (diluted) for any overburden, till, or partial backfill resulting from prior mining activities. 15.2.2 General Pit Slope The general overall pit slopes used in the optimization were 50° in the hangingwall (north wall) and 48° in the footwall (south wall). Since the pit optimization program does not produce an ultimate pit design with a final haul ramp, geotechnical berms and a proper benching arrangement, angles are taken to be slightly shallower than the final pit design slopes, as presented in section 15.4.1, to ensure that the ultimate pit design slopes are respected (refer to section 15.4.1). 15.2.3 Mining Dilution No additional dilution was added during the pit shell optimization routine since an inherent grade dilution of 11.7% is included in the OK block model. 15.2.4 Costs and Gold Price The engineered pit designed for this estimate was based on an optimized pit shell using a gold price is US$1,000/oz with an exchange rate of US$1.00=Cdn$1.03. Other main pit optimization parameters are summarized in Table 15-2. Table 15-2

Cost Summary Used for Pit Optimization

Costs ($/t) 1

Waste

Ore

Mining ($/t mined)

2.19

2.19

OB Mining ($/t mined)

1.80

-

Milling ($/t milled)2

-

9.75

G&A ($/t milled)

-

2.72

Incremental Cost ($/t/bench)

0.024

1

Operating costs used to derive the economic pit shell. 2 Including $1.25/tonne milled for ongoing TMA sustaining cost.

15.2.5 Mill Recovery The gold recovery was calculated for each ore block in the 3D model. The estimated gold recovery curves were obtained from metallurgical test work conducted at a 48 hour leach time and adjusted to a leach time of 29 hours for the base case, as presented in the feasibility study. The test results provided a derivation of five recovery equations to be applied to the major rock types as follows:

4 February 2014

15-3

Mineral Reserve Estimates



For the rock type MF: y1 = 1.6289 Ln(Au) + 91.09;



For the rock type PF: y1 = 0.6458 Ln (Au) + 92.04;



For the rock type KMF: y1 = 1.6868 Ln(Au) + 90.91;



For the rock type KPF: y1 = 2.546 Ln(Au) + 88.49; and



For other rock types, the average was used: y1 = 1.8687 Ln (Au) + 91.14.

The gold recovery values are calculated for all ore blocks in the Measured and Indicated categories in the block model. Additional test work conducted for the feasibility study on a bulk sample at 29 hours leach time confirmed the results of the average gold recovery of the reserves in the block model. Review of the process plant data from October to December 2013 indicated that the gold recovery was 1 to 3% higher than predicted by the pre-feasibility and feasibility studies model. Based on this data, a 1% gold recovery increase was added to the gold recovery model for the LOM plan. 15.2.6 Mill Cut-off Grade The mill CoG was calculated using the cost data and parameters and gold price presented above. It also includes a 2% royalty payment, a refining and freight cost of $5/oz and a minimum profit of $0.01/tonne. The cost parameters used for the calculation of the mill CoG are summarized in Table 15-3. Table 15-3

Mill Cut-Off Grade Calculation

Items Gold Price Exchange Rate

1.03

US$/oz US$/Cdn$

$1.25

/t milled

Milling Cost

$8.50

/t milled

General and Administration

$2.72

/t milled

$12.47

/t milled

Gold Price

$1,030.93

Gold Price

33.15

$/g

Recovery Gold Gross Value Royalty (2%) Refining

$/oz

91.5

%

30.33

$/g

0.60

$/g

0.161

$/g

Gold Payments

99.935

%

Minimum Profit

0.01

$/g

Net Gold Value

29.53

$/g

Cut-Off Grade

0.422

g/t

0.50

g/t

Elevated CoG USED (incl. 4% dilution)

15-4

1,000

Unit

TMA ongoing Cost

Total Operating Cost

1

Value

Where y = recovery (%) and Au = grade of gold to the mill in g/t. 4 February 2014

Detour Lake Mine NI 43-101 Technical Report

15.3 Pit Optimization Results Using the LG 3D algorithm, the optimized pit shell was generated for a CoG of 0.50 g/t Au using the parameters listed above. Figure 15-1 Plan View – Pit Optimization at $US1,000/oz

Maximum elevation -= 6,288 metres

Minimum elevation -= 5,676 metres

15.4 Engineered Pit Design Parameters In order to maximize the gold recovery inside the engineered pit design, both the optimized pit shell obtained from the LG optimization process and the engineered mine design from BBA (2012) were used as main guides. The resulting pit design includes practical geometry that is required in an operational mine, such as the haul road to access all the benches, recommended pit slopes with geotechnical berms, proper benching configuration and smoothed pit walls. The resulting engineered pit design is used for the mineral reserve statement in this report. 15.4.1 Geotechnical Considerations and Bench Configuration The geotechnical considerations and bench configuration details were provided by Golder (BBA, 2012 – Golder, February 2011) following additional assessment after the feasibility study. The results of this review are schematically represented in Figure 15-2.

4 February 2014

15-5

Mineral Reserve Estimates

Figure 15-2 Pit Slope Recommendations

The bench face angles vary from 65° to 75° and the inter ramp angles vary between 46o to 56°. The resulting berm widths created by the slope configuration in each sector range from 9.5 to 12 metres wide. The final pit was designed using a double benching configuration, with a berm at every 24 metres of vertical height in the bedrock. The pit design was expanded at every 12 metres to match the height of the blocks in the resource model. In addition to the bench geometry and configuration, Golder also provided additional design requirements, including an overburden zone, a transitional zone and geotechnical berms for the complete pit design as follows: 

The Overburden Zone is characterized as the material directly above the bedrock and is coded separately in the block model. This zone ranges from 6,252 metre EL to the surface and is to be designed with the following details: 

15-6

Pit slope of 26°; and 4 February 2014

Detour Lake Mine NI 43-101 Technical Report

 

A 10 metre berm at 6,252 metre EL (contact between bedrock and overburden).

The Transition Zone (weathered zone), as detailed by Golder, is generally located between 24 metres to 48 metres below the overburden zone (from 6,228 metres EL to 6,252 metres EL) for all pit wall sectors except for the north wall (hanging wall). This section in the pit design should have the following design parameters: 

12 metres bench heights;



Bench face angle of 65°;



Inter ramp angle of 45°; and



A 6.5 metre berm at every 12 metres bench.

Provisions for geotechnical berms of 15 metres are to be included at every 144 metres of vertical separation instead of the standard 8 metre berm. In the 2011 report, Golder recommended a program of ongoing geotechnical documentation and monitoring to be implemented, in particular, for excavating through the weaker talc-chlorite units and/or in close proximity to the existing underground openings. The slope stability-monitoring program is to be implemented early on in pit operations to gain experience with the rock mass behaviour prior to excavating the final pit walls. Golder also recommended additional stability analysis to be carried out if future engineered pit configurations change appreciably from the feasibility study. Application of the revised pit slope angles does not change substantially the ultimate pit shell when compared to that used in the feasibility study. 15.4.2 Final Ramp Design The final ramp was designed to a 35 metre width in order to support two-way uninterrupted haulage cycles using the expected truck widths. This is based on the industry standard for the running width of a haul road to be approximately three times the width of the largest equipment, not including additional allocation for the drainage ditch and safety berms. For the last stretch of the ramp near the pit bottom, the haul road is narrowed down to a single traffic lane of 20 metres in order to reduce the pit design stripping ratio. The ramp gradient used was 10%, with a 2% cross slope to facilitate drainage. Figure 15-3 displays a typical profile of the haulage ramp with the dimensions.

4 February 2014

15-7

Mineral Reserve Estimates

Figure 15-3 Typical Ramp Profile and Dimensions

15.5 Pit Design Results The ultimate pit design was completed using the design parameters described in the previous section. The pit design, containing all the features required for an operating mine, is displayed in Figure 15-4. Figure 15-4 Ultimate Pit Design – Plan View

15-8

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

15.6 Mining Dilution and Mining Loss Evaluation The mining dilution and mining loss factors have been re-evaluated since BBA (2012). After nearly one year of milling operations (gold production started in February 2013), mine to mill reconciliation has shown steady improvement, reaching approximately 4% during the month of November. Based on these results, an average mining dilution of 4.0% at a grade of 0.20 g/t Au was applied for the LOM reserves estimates. The overall dilution amounts to 15.7% when combining the mining dilution 4.0% and the inherent dilution of 11.7% built in the OK block model. For 2014, mining dilution is estimated at 7.0% at a grade of 0.20 g/t Au. The mining loss is 5% as in BBA (2012).

15.7 Reserve Statement The mineral reserve and stripping estimates, based on the engineered pit design criteria presented above, have been calculated after allowance for additional mining dilution of 4% at a grade of 0.20 g/t Au and ore losses of 5%. The Proven and Probable mineral reserves total 474.0 Mt at 1.02 g/t Au for 15.6 million ounces of contained gold. An inventory of 2.4 Mt of ore grading 0.82 g/t Au is also stockpiled as of December 31, 2013. The Proven and Probable mineral reserves are summarized in Table 15-4 along with the ore in stockpiles and strip ratio. Table 15-4

Category

Mineral Reserves Estimate using a Cut-off Grade of 0.50 g/t Au (including 4.0% dilution at 0.20 g/t Au and 5% ore loss)

Tonnes (Mt)

Grade (g/t Au)

Contained Gold Ounces (000’s)

Recovery (%)

Recoverable Gold Ounces (000’s)

94.4

1.29

3,901

92.6%

3,612

Probable

379.7

0.95

11,585

92.0%

10,663

Total P&P

474.0

1.02

15,486

92.2%

14,275

Stockpile 1

2.4

0.82

63

91.8%

58

476.4

1.02

15,549

92.2%

14,333

Inferred

6.7

0.73

91.6%

145

Fill (Old UG)

7.9

Overburden

78.8

Proven

Total

Rock

1,582.4

Total Waste

1,675.7

1 2

Strip Ratio 3.542

As of December 31, 2013. Excluding stockpile material.

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Detour Lake Mine NI 43-101 Technical Report

16.0 Mining Methods 16.1 Introduction Surface mining of the Detour Lake mine follows the standard practice of an open-pit operation, with conventional drill and blast, load and haul cycle using a drill/truck/shovel mining fleet. Overburden is loaded and hauled to the overburden stockpile area near the pit. Hard rock waste is drilled, blasted, loaded by hydraulic and rope shovels then delivered by large mining trucks to the waste rock storage areas. The run-of-mine ore is drilled, blasted, loaded by hydraulic and rope shovels and delivered by large mining trucks to the primary crusher or stockpiles near the crusher.

16.2 Mine Production Plan This mine production plan was completed on a on a quarterly basis for 2014 and 2015, and annually thereafter. The mine plan was developed according to the mill schedule as provided by Detour Gold as follows: 19 Mt in 2014, 20.1 Mt in 2015, 21.3 Mt in 2016 and 22.26 Mt annually thereafter. The overall mine plan was conceived to prioritize the availability of ore while delaying the waste stripping required, maximizing the NPV. While the mine production plan generally follows the pit phasing developed during the feasibility study and subsequent reports (BBA 2010, 2011, and 2012), the current plan was carried out to include additional mining to the west, as well as to advance the breakthrough with the Campbell pit in order to access higher grade ore. As in previous mine plans, till is required for tailings dam construction. Pit stages and the annual mine plans were developed following the pit design criteria presented in section 15.4. Between each mining phase, there is a transitional period where the stripping of the next phase is started before the end of the previous phase. The transitional periods are broken down into a series of mining pushbacks to delay waste stripping while maintaining a feasible mining sequence. A minimum pushback mining width of 100 metres to 150 metres was used during the mine planning exercise. In addition, attempts were made to respect a maximum vertical separation between active mining faces of 150 metres. A mining dilution factor of 7% in 2014 and 4% in subsequent years was used as a result of operational experience gained over 2013 and to account for the improvement in dilution management practices. 16.2.1 Annual Mine Plan Results The annual mine production plan is based on the current mineral reserve estimate and is presented in Table 16-1. Total mined tonnage is 92 Mt for 2014. During the peak period, mining rate increases gradually to 138 Mt in 2018 and peaks at 141 Mt from years 2019 to 2021, with the strip ratio ranging from 5.20 to 5.37 tonnes in 2018 to 2021, with a peak at 5.37 in 2020. After 2020, the strip ratio decreases steadily until the end of the LOM. 4 February 2014

16-1

Mining Methods

The production forecast gradually increases from 490,254 oz of gold in 2014 to 685,933 oz in 2018, averaging 598,348 oz per year during that five-year period. As higher grade ore is encountered as the pit gets deeper, gold production exceeds 800,000 oz per year for three years toward the end of the LOM. The long-term strategy is to build an adequate stockpile equivalent to approximately three months of mill feed. In addition to an opening stockpile balance of 2.41 Mt of ore at 0.82 g/t Au as of December 31, 2013, it is estimated that 2.69 Mt at 0.87 g/t Au and 2.87 Mt at 0.89 g/t will be stockpiled in 2015 and 2016, respectively. By year-end 2016, an estimated total stockpile balance of 8.0 Mt of ore at an average grade of 0.86 g/t Au will be available to be reclaimed on an “as needed basis”. Left-over stockpile ore will be reclaimed at the end of the LOM in year 2035. A graph summarizing the annual material movement schedule is presented in Figure 16-1. Furthermore, Figure 16-2 presents the yearly mill head grade and gold production profile. The end of period mining plots illustrating mining progression can be found in sub-section 16.2.2. Figure 16-1 Annual Material Movement Breakdown

16-2

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Detour Lake Mine NI 43-101 Technical Report

Figure 16-2 Annual Head Grade and Gold Production Profile

4 February 2014

16-3

Mining Methods

Table 16-1

Detour Lake Project 61,000 tpd Mine Production Plan with Dilution and Ore Loss

Ore Tonnes Mined Period Tonnes (kt) Opening Balance 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035

21,691 22,942 21,301 22,265 22,265 22,265 22,265 22,265 22,265 22,265 22,265 22,265 22,265 22,265 22,265 22,265 22,265 22,265 22,265 22,265 22,265 7,320

Total

47,024

Au (g/t)

0.87 0.91 0.93 1.04 1.04 0.83 0.86 0.95 0.88 1.01 1.00 1.02 0.89 0.99 1.11 0.99 1.12 1.09 1.24 1.24 1.25 1.25 4

1.02

Ore Tonnes Mined to 1, 2 HG Stkp Tonnes (kt)

Au (g/t)

2,415

0.82

2,691 2,867

Recovery

Tonnes (kt)

Au (g/t)

%

0.87 0.89

19,000 20,075 21,301 22,265 22,265 22,265 22,265 22,265 22,265 22,265 22,265 22,265 22,265 22,265 22,265 22,265 22,265 22,265 22,265 22,265 22,265 15,293

0.87 0.91 0.93 1.04 1.04 0.83 0.86 0.95 0.88 1.01 1.00 1.02 0.89 0.99 1.11 0.99 1.12 1.09 1.24 1.24 1.25 1.05

91.9% 92.0% 92.0% 92.2% 92.2% 91.8% 91.9% 92.0% 91.9% 92.2% 92.1% 92.2% 91.9% 92.1% 92.3% 92.1% 92.4% 92.3% 92.5% 92.5% 92.6% 92.2%

0

476,439

1.02

92.2%

-7,973 0

Ore Tonnes Milled

Production

3

Mineralized Waste

Tonnes (kt)

Grand Total Mined Tonnes (kt)

Strip Ratio

OB

Waste Rock

Tonnes (kt)

Tonnes (kt)

Au (g/t)

490,254 542,610 588,112 684,832 685,933 542,560 565,359 627,201 577,384 668,434 658,966 670,201 582,933 650,690 731,842 655,740 741,684 719,348 822,519 823,485 828,874 474,499

6,265 6,331 6,243 5,356 4,557 8,056 6,924 6,077 6,644 5,484 4,369 4,690 5,431 4,643 3,393 5,290 3,593 4,758 2,928 2,975 2,198 1,149

0.45 0.45 0.45 0.45 0.45 0.45 0.45 0.45 0.45 0.45 0.45 0.45 0.45 0.45 0.45 0.45 0.45 0.45 0.45 0.45 0.45 0.45

11,781 12,651 9,619 7,653 9,537 13,075 9,500 4,840 92 56

52,414 59,473 84,126 94,158 101,720 97,997 103,172 107,165 106,235 100,400 83,475 74,654 69,105 69,226 69,179 57,306 59,804 48,796 23,004 19,698 8,071 407

92,150 101,398 121,290 129,431 138,079 141,401 141,861 140,347 135,235 128,205 110,109 101,609 96,801 96,134 94,836 84,861 85,662 75,820 48,197 44,937 32,534 8,876

3.25 3.42 4.69 4.81 5.20 5.35 5.37 5.30 5.07 4.76 3.95 3.56 3.35 3.32 3.26 2.81 2.85 2.41 1.16 1.02 0.46 0.21

14,333,459

107,362

0.45

78,805

1,489,584

2,149,774

3.54

(oz)

1

Negative stockpile tonnages denote material to be withdrawn from stockpile and sent to the mill. 2 Ounces of production are exclusive of inventory changes. 2013 assumed to include 12,715 ounces in inventory (GIC). Inventory is recovered in 2035. 3 This material is NOT part of the reserve. 4 Dilution of 7% at a grade of 0.2 g/t Au used from 2012-2014. 4% dilution at 0.2 g/t Au thereafter. 5% ore loss included for all years. 5 Strip Ratio = (Waste Rock + Overburden + Mineralized Waste) / Mined Ore Tonnes.

16-4

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Detour Lake Mine NI 43-101 Technical Report

16.2.2 End-of-Period Mine Production Plans 2012 – 2035 Year-end mine production plans are displayed in Figure 16-3 to Figure 16-30 (shown in quarterly periods for 2014-15). Additionally, section views illustrating the pit progression in five-year increments are presented in Figure 16-31 to Figure 16-35. The arrows on the figures illustrate the anticipated primary haul roads. The thicker black line illustrates the ultimate pit limits. The final achieved period depth is noted in the bottom right hand corner of each figure. Figure 16-3 End of 2014-03 – Year 1

Figure 16-4 End of Period 2014-06 – Year 1

4 February 2014

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Mining Methods

Figure 16-5 End of Period 2014-09 – Year 1

Figure 16-6 End-of-Period 2014-12 – Year 1

16-6

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Figure 16-7 End-of-Period 2015-03 – Year 2

Figure 16-8 End-of-Period 2015-06 – Year 2

4 February 2014

16-7

Mining Methods

Figure 16-9 End-of-Period 2015-09 – Year 2

Figure 16-10 End-of-Period 2015-12 – Year 2

16-8

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Figure 16-11 End-of-Period 2016 – Year 3

Figure 16-12 End-of-Period 2017 – Year 4

4 February 2014

16-9

Mining Methods

Figure 16-13 End-of-Period 2018 – Year 5

Figure 16-14 End-of-Period 2019 – Year 6

16-10

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Figure 16-15 End-of-Period 2020 – Year 7

Figure 16-16 End-of-Period 2021 – Year 8

4 February 2014

16-11

Mining Methods

Figure 16-17 End-of-Period 2022 – Year 9

Figure 16-18 End-of-Period 2023 – Year 10

16-12

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Figure 16-19 End-of-Period 2024 – Year 11

Figure 16-20 End-of-Period 2025 – Year 12

4 February 2014

16-13

Mining Methods

Figure 16-21 End-of-Period 2026 – Year 13

Figure 16-22 End-of-Period 2027 – Year 14

16-14

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Figure 16-23 End-of-Period 2028 – Year 15

Figure 16-24 End-of-Period 2029 – Year 16

4 February 2014

16-15

Mining Methods

Figure 16-25 End-of-Period 2030 – Year 17

Figure 16-26 End of Period 2031 – Year 18

16-16

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Figure 16-27 End of Period 2032 – Year 19

Figure 16-28 End of Period 2033 – Year 20

4 February 2014

16-17

Mining Methods

Figure 16-29 End of Period 2034 – Year 21

Figure 16-30 End of Period 2035 – Year 22

16-18

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Figure 16-31 Mine Plan Section View 18,000E – Y2, Y7, Y12, Y17

Figure 16-32 Mine Plan Section View 18,500E – Y2, Y7, Y12, Y17

4 February 2014

16-19

Mining Methods

Figure 16-33 Mine Plan Section View 19,000E – Y2, Y7, Y12, Y17

Figure 16-34 Mine Plan Section View 19,500E – Y2, Y7, Y12, Y17

16-20

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Figure 16-35 Mine Plan Section View 20,000E – Y5, Y10, Y15, Y20

16.2.3 Overburden and Waste Rock Disposal Areas The design parameters for the rock and overburden piles remain unchanged from the feasibility study. The major design parameters and specifications to the construction methodology of the waste and overburden piles are summarized as follows: 

Rock pile swell factor (net): 30%;



Overburden pile swell factor (net): 20%;



Individual final lift slopes will follow a slope equivalent to the angle of repose of the material. This is 1.3H: 1V, which is equivalent to 34°;



The assumed subsurface condition of the North and South waste rock piles is a soft clay foundation;



For waste rock piles over a foundation containing clay, an initial lift of 3 metres (parallel to topography), followed by a 6 metre lift is required; and



Minimum setbacks must be respected for tributaries/water bodies (120 metres), tailings dams (100 metres), landfills (100 metres), roads and infrastructure (50 metres), and from the perimeter of the open pit (200 metres).

The design capacities of the various waste rock piles and the mineralized waste were updated with respect to the quantities in the mine plan, quantities placed on various piles in 2013 and quantities of material required for tailings dam construction. The waste and mineralized waste storage areas have the required capacities to contain the materials in the mine plan. The designed capacity for the waste rock piles, mineralized waste stockpiles and the overburden pile are as follows:

4 February 2014

16-21

Mining Methods

Overburden Pile 

Overburden:

34 Mm3;

North Pile 

Mineralized waste

13.5 Mm3;



NAG material

59.0 Mm3; and



PAG material

133.0 Mm3.

South Pile 

Minelized waste

34.5 Mm3; and



NAG material

487.5 Mm3.

The placements for the piles, as well as the crusher location and the final pit design, are shown in Figure 16-36 (in the drawing, mineralized waste is abbreviated as “MW”). The North rock pile is accessed from the North Ramp from 2012 until 2018, when it reaches design capacity. The open pit ramp exits to the North until the end of 2018 at which time an access is via the South rock pile. One important design aspect is the area reserved for PAG material coming from the open pit mine. The PAG material was projected to account for up to 20% of the total waste material. Starting in the first year of production, a separate ramp access becomes available for the PAG section, which is reserved in the southernmost region of the North pile. The placement of the PAG is chosen based on the watersheds and southbound flow of all tributaries in the area. As well, a section of the south side of the North rock pile will also be reserved for mineralized waste stockpile material.

16-22

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Figure 16-36 Final Pit and Pile Locations

16.2.4 Mineralized Waste Stockpile The material falling between a grade of 0.4 g/t and 0.5 g/t Au will be placed in a stockpile. The average grade of the mineralized waste stockpile is approximately 0.45 g/t Au over the LOM. The total amount of mineralized waste material to be placed in the stockpile is 107.4 Mt. Two mineralized waste stockpiles can be accessed from the North Ramp and the South Ramp and are placed adjacent to the waste rock piles. The mineralized waste is being segregated (stockpiled) as it has the potential of being processed in the future.

16.3 Mining Equipment Selection The estimated fleet required for 2014 and 2015 is based on the equipment already purchased, or expected to be delivered to site in the short-term. The equipment required for the years 2016 to 2035 is calculated from the mine production schedule and considers various operating parameters: expected operating conditions, haulage profiles, production cycle times, mechanical availabilities, and overall utilization. The primary fleet is based on conventional open pit mining operations and consists of haul trucks, electric cable and hydraulic shovels and drill rigs. Support equipment was selected to match the primary equipment fleet and includes track-type dozers, wheel-type dozers, motor-graders, water, lube and fuel trucks, as well as other maintenance support equipment. 4 February 2014

16-23

Mining Methods

Equipment additions and replacement are calculated by comparing equipment operating life to the remaining mine life. 16.3.1 Primary Equipment Operating Times The net productive operating times are determined for loading and hauling, as well as for drilling. They are based on a 360-day per year operation of two 12-hour shifts per day, resulting in 720 available shifts per year. Shift parameters and net productive hours for loading, hauling and drilling activities are presented in Table 16-2. Table 16-2

Shift Parameters and Net Productive Operating Hours Shift Parameters Parameters

Time 2

Shift/Day Hours/Shift

12

Days/Year

365

Lost Days

5

Days Available per Year

360

Shifts/Year

720

Net Productive Operating Time Parameters

Time/Shift (min) Trucks & Shovels

Drills

720

720

Shift Change + Safety Talks

15

15

Inspection + Fuelling + Water

15

15

Coffee Break

20

20

Lunch

30

30

80

80

640

640

83%

75%

108.8

160

188.8

240

531.2

480

8.85

8.00

Scheduled Time Per Shift Scheduled Delays

Net Scheduled Net Scheduled Productive Time Job Efficiency Factor (Post Scheduled Breaks) Time Lost to Job Efficiency Total Delays per Shift (min) Net Productive Operating Time/shift (min) Net Productive Operating Hours/shift (hr)

16-24

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

16.3.3 Equipment Availability and Utilization Availability profiles for shovels and trucks were based on general manufacturer benchmarks and an age-based maintenance plan. Newer units can expect highest availabilities due to the age of fleet and potential manufacturer guaranteed rates. For the truck fleet, a minimum availability of 88% was assumed for all of the LOM. The annual forecast for the availability of the mine fleet presented in Table 16-3 is based on the number of units at each age and reflects adding new units (or retiring old units in the fleet). Utilization also takes into consideration the improved skills of the operators over time. Table 16-3

Mechanical Availability and Utilization

Haul Trucks

2014

2015

2016

2017

2018

87%

87%

87%

87%

87%

87%

90%

98%

98%

98%

98%

98%

83%

83%

83%

83%

83%

83%

Availability

87%

86%

86%

85%

84%

83%

Utilization Adjustment

95%

95%

95%

95%

95%

95%

Efficiency Factor

83%

83%

83%

83%

83%

83%

Availability

87%

86%

86%

85%

84%

83%

Utilization Adjustment

95%

95%

95%

95%

95%

95%

Efficiency Factor

83%

83%

83%

83%

83%

83%

Availability

97%

86%

86%

85%

84%

83%

Utilization Adjustment

95%

95%

95%

95%

95%

95%

Efficiency Factor

83%

83%

83%

83%

83%

83%

Availability

87%

87%

87%

87%

87%

87%

Utilization Adjustment

95%

95%

95%

95%

95%

95%

Efficiency Factor

75%

75%

75%

75%

75%

75%

Availability

87%

87%

87%

87%

87%

87%

Utilization Adjustment

95%

95%

95%

95%

95%

95%

Efficiency

75%

75%

75%

75%

75%

75%

Availability

87%

87%

87%

87%

87%

87%

Utilization Adjustment

90%

90%

90%

90%

90%

90%

Efficiency Factor

75%

75%

75%

75%

75%

75%

Availability CAT 795 F

Utilization Adjustment Efficiency Factor

1

2019-2035

Shovels

CAT 7495

CAT 6060 FSD

CAT 6060 FSE Drills Atlas Copco 271D

Atlas Copco 271E

SmartROC D65 1

Job efficiency factor as calculated in Table 16-2.

4 February 2014

16-25

Mining Methods

16.3.5 Drilling Drill pattern design was derived from the need to minimize dilution and damage on pit walls, control fragmentation, and material movement along the contacts, while reducing the cost of blasting. The Atlas Copco Pit Viper 271 and SmartROC D65 drills (currently in use at the mine) are capable of drilling 216 mm and 165 mm diameter blast holes respectively. The bench height is 12 metres. Typical drill patterns for the PV271 are 6 x 6.5 metres in ore and 7 x 7.5 metres in waste material. For the D65 drills, typical patterns are 4.8 x 5.2 metres in ore and 5.6 x 6.0 metres in waste. For the D65 drills, typical patterns are 4.8 x 5.2 metres in ore and 5.6 x 6.0 metres in waste. Table 16-4 shows the tonnes of material that are covered by a drill during a shift, with eight net productive operating hours per shift and a penetration rate of 28 metres and 22 metres for the PV271 and D65 respectively per hour. Blast holes are drilled to a total depth of 13.5 metres, including 1.5 metres of sub-drilling. A stemming length of four metres was selected to maximize the explosive column’s effectiveness. Table 16-4

Drilling Specifications

Parameters

Atlas Copco 271D Ore

Ore

Pre-split

Units

Waste

Hole Diameter

8½

8½

6½

6½

5½

Hole Diameter

216.0

216.0

165.1

165.1

140.0

Bench Height

12.0

12.0

12.0

12.0

12.0

M

Sub-drill Length

1.5

1.5

1.5

1.5

0

M

Bulk Density

2.9

2.9

2.9

2.9

2.9

inches mm

t/m3

Hole Spacing

6.0

7.0

4.8

5.6

2.0

M

Burden

6.5

7.5

5.2

6.0

0.5

m

1,357

1,827

869

1,169

35

tonnes/hole

Penetration Rate

28

28

22

22

12

m/h

Shift Drill Time

8.0

8.0

8.0

8.0

8.0

hr

224.0

224.0

176.0

176.0

96.0

m

5%

5%

5%

5%

5%

%

15.80

15.80

12.40

12.40

7.60

holes

21,447

28,871

10,784

14,518

265

tonnes

Rock Mass per Hole 1

Meters/Shift Re-drill Holes/Shift Tonnes/Shift 1

16-26

Waste

SmartROC D65

Instantaneous penetration rate.

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

16.3.7 Blasting The blast patterns designs and explosives column heights result in powder factors of 0.321 kg/t for ore and 0.238 kg/t for waste for the PV271. For the D65, the powder factor is 0.323 kg/t for ore and 0.240 kg/t for waste. The overall explosives consumption is based on 100% bulk emulsion usage, resulting in 435.1 and 281 kg of explosive for PV271 and D65 per hole respectively. The blasting specifications for ore and waste are presented in Table 16-5. Table 16-5

Blasting Specifications

Parameters

Atlas Copco 271D

SmartROC D65

Pre-split

Units

Ore

Waste

Ore

Waste

Hole Diameter

216.0

216.0

165.1

165.1

140.0

Bench Height

12.0

12.0

12.0

12.0

12.0

m

Sub-drill Length

1.5

1.5

1.5

1.5

0

m

Stemming Length

4.0

4.0

3.0

3.0

4.0

m m

Loaded Length

mm

9.50

9.50

10.50

10.50

8.0

Volume/m

0.037

0.037

0.021

0.021

0.015

Rock Mass Per Hole

1,357

1,827

869

1,169

35

Powder Factor

0.321

0.238

0.323

0.240

4.421

Usage

0%

0%

0%

0%

0%

Density

0.84

0.84

0.84

0.84

0.84

Kg/Hole

0.0

0.0

0.0

0.0

0.0

kg

100%

100%

100%

100%

100%

%

Density

1.25

1.25

1.25

1.25

1.25

Kg/Hole

435.1

435.1

281.0

281.0

153.8

1.25

1.25

1.25

1.25

1.25

m3/m tonnes/hole kg/tonne

ANFO % g/cc

Bulk Emulsion Usage

Explosive Average Density

4 February 2014

g/cc kg g/cc

16-27

Mining Methods

16.3.8 Loading The current primary loading fleet consists of three 28 m3 CAT 6060 hydraulic shovels and two 48m3 CAT 7495 rope shovels. The shovel size was matched with a fleet of 320-tonne CAT 795F trucks. This fleet combination requires 5.5 passes for a hydraulic shovel to fill a truck, while a rope shovel requires 3 passes. Although interchangeable, the hydraulic shovels will primarily be operating in ore and overburden zones, while the rope shovels will primarily be operating in waste zones. Table 16-6 presents the net production capacities for both types of shovel in ore, waste, and overburden. These assumptions and specifications are suitable for long term planning. The current LOM plan production requirements, combined with Detour Gold’s existing loading fleet reach a maximum of 90% of the Net Production Capacity outlined below. Table 16-6

Loading Specifications Material

Parameters

Ore/Waste

Overburden

Loading Tool

CAT 6060

CAT 7495

CAT 6060

Truck

CAT 795F

CAT 795F

CAT 795F

28

48

28

Fill Factor

92%

95%

92%

%

In-situ Bulk Density

2.90

2.90

1.80

t/m3

Swell Factor

30%

30%

20%

%

Loose Density

2.23

2.23

1.5

Tonnes per Bucket

57.5

101.7

38.6

tonnes

Truck Capacity

318

318

318

tonnes

Time/Pass

0.67

0.67

0.67

min

Passes/Truck

5.53

3.13

8.23

passes

Rounded

5.50

3.00

8.00

passes

Loading Time (Full Pass #)

4.00

2.00

5.33

min

Truck Leaving Time

0.25

0.25

0.25

min

Truck Spot Time

0.33

0.33

0.33

min

Total Time/Truck

4.6

2.6

5.9

min/truck

NPOH/Shift

8.9

8.9

8.9

hours

Truck Loads/Shift

116

206

90

loads/shift

316.1

305.2

309.1

tonnes/trip

88%

88%

88%

90%

90%

90%

29,011

49,699

21,980

tonnes/shift

20,888,031

35,782,942

15,825,803

tonnes/year

Bucket Size

Tonnes per Trip 1

Mechanical Availability Utilization Factor

1

Net Shift Production Capacity Net Yearly Production Capacity 1

16-28

Units

Ore/Waste

m3

t/m3

Varies as per Table 16-3.

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

16.3.10

Hauling

Average annual haul profiles were created based on the mine production plan. Haul routes were traced in the MineSight software, starting at the center of gravity for each mining cut for each bench, to the final destination. The following scheduling was used for short-term mine plan: 

2014 and 2015: quarterly; and



2016 and subsequent years: annually.

The material was sent to one of four destinations: 

Ore crusher;



North waste pile (years 2014-2018);



South waste pile (years 2019-2035); or



Overburden pile.

Haul truck travel speeds were based on manufacturer’s Rimpull charts (including an average rolling resistance of 3%) and were used to determine the average annual cycle times. These cycle times were then used to determine the annual haulage fleet size. Table 16-7 presents the general haulage distance template used for each material type. Truck speed assumptions are presented in Table 16-8. Table 16-7

Haulage Distance Template for each Material Type Ore

In-pit flat distance

Inclined distance ramp @ 10% in pit at exit point

Distance on surface flat

Up-ramp distance to crusher 10%

Flat distance to crusher

Ramp 10% to waste pile

Flat distance on waste pile

Ramp 10% to OB pile

Flat Distance on OB pile

Waste In-pit horizontal distance

Inclined distance ramp @ 10% in pit at exit point

Distance to waste pile Overburden

In-pit flat distance

Table 16-8

Inclined distance ramp @ 10% in pit at exit point

Truck Speed Assumptions Loaded (km/h)

Empty (km/h)

Flat In-pit

25

30

Flat Ex-Pit

40

45

10% Uphill

12.7

25

17

25

10% Downhill

4 February 2014

Flat 2% Distance on surface to OB pile

16-29

Mining Methods

16.3.11

Maintenance and Repair Contract

Detour Gold has a maintenance and repair contract agreement (“MARC”) with CAT dealer Toromont for the CAT 795F truck fleet. The MARC consists of a variable sliding scale hourly cost and a fixed overhead fee. The variable costs were calculated using the assumption that each truck will operate 10.7 hours per shift. The cost profile of each truck was considered individually. A weighted average cost per hour for each period for each truck was determined based on the hours accumulated in the period, the truck’s total machine hours and the MARC interval rates. Trucks were retired at the end of the year once they have accumulated 84,000 machine hours. Based on the haul distance, loading productivity/drilling productivity data, as well as the equipment availability, the annual fleet requirements for the major mine equipment (drills, shovels, loaders and trucks) has been determined. The truck fleet is graphically represented in Figure 16-37. A maximum of 41 trucks is required for years 2026 to 2031. Figure 16-37 Annual Truck Fleet Requirements

16-30

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

The quantity of support equipment required was based on operational factors, such as the quantity of loading units to service and quantity of waste dumps, stockpiles and roads to maintain. The support equipment includes: 

CAT 16-M (Wheel Grader);



CAT 24-M (Wheel Grader);



Wheel Dozer (CAT 844H);



Track Dozer (DAT D10T);



Wheel Dozer (CAT 980); and



Track Dozer (CAT D11T).

Sustaining capital of $475.6 million during years 2015 to 2035 for additions, replacements and re-builds of mining equipment (exclusive of workshop extensions) has been estimated to match the annual production schedule tonnages and unit operating hours of the mining fleet. Due to the extended mine life, equipment replacements will be required, including a total of 30 trucks, three hydraulic shovels and seven drills. The equipment life of the electric rope shovels was assumed to be in excess of the mine life, provided they remain adequately maintained. The graders and dozers will each be replaced after a useful life of eight years. In addition, some auxiliary equipment, such as, light towers, light plants and fuel trucks will be replaced sequentially in years 9, 10, and 11. Table 16-9 presents the expected machine life in gross operating hours for the primary and support fleet as well as corresponding retirement age. Table 16-9

Primary and Support Fleet GOH Operating Hours

Years

Hydraulic Shovel

80,000

13

Loader

45,000

10

Truck

84,000

13

Drill

65,000

10

W. Dozer

45,000

8

T. Dozer

45,000

8

Grader

45,000

8

Water truck

80,000

13

The complete list of primary and support equipment required over the LOM is presented in Table 16-10. Table 16-11 presents the replacement schedule for primary, support and auxiliary fleet.

4 February 2014

16-31

Mining Methods

Table 16-10 Annual Mining Fleet Requirements Equipment List

2015

2016

2017

2018

2019

2020

2021

2022

2023

2024

2025

2026

2027

2028

2029

2030

2031

2032

2033

2034

2035

Max.

24

32

38

38

38

38

38

38

38

38

38

41

41

41

41

41

41

28

28

18

5

41

CAT 7495

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

1

1

1

1

2

CAT 6060FSD

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

CAT 6060FSE

1

1

1

1

1

1

1

1

1

1

1

0

0

0

0

0

0

0

0

0

0

1

CAT 6030FSE

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

Atlas Copco Pit Viper 271D

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

3

3

3

2

4

Atlas Copco Pit Viper 271E

2

2

3

3

3

3

3

3

3

3

2

2

2

2

1

1

1

0

0

0

0

3

SmartROC D65

2

3

3

3

3

3

3

3

3

2

2

2

2

2

2

2

2

2

2

1

1

3

CAT980

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

CAT 16M

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

CAT 24M

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

CAT 844H

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

CAT D10T

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

CAT D11T

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

39

25

67

Haul Truck Fleet CAT 795F AC Shovel Fleet

Drill Fleet

Support Fleet

Total

16-32

51

60

67

67

67

67

67

67

67

66

65

67

67

67

66

66

66

50

50

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Table 16-11 Mining Fleet Replacement Schedule Equipment List

2014

2015

2016

2017

2018

2019

2020

2021

2022

2023

2024

2025

2026

2027

2028

2029

6

6

6

6

6

2030

2031

2032

2033

2034

2035

Total

Haul Truck Fleet CAT 795F AC

30

Shovel Fleet CAT 7495 2

CAT 6060FSD

1

3

CAT 6060FSE 1

1

2

4

2

1

7

1

1

CAT 6030FSE Drill Fleet Atlas Copco Pit Viper 271D Atlas Copco Pit Viper 271E SmartROC D65

2

Support Fleet CAT980 2

CAT 16M

2 1

CAT 24M

1

2

2

CAT 844H

2

CAT D10T

2

2

2

2

8

CAT D11T

1

1

1

1

4

Total

3

5

9

11

4 February 2014

1

2

5

4

4

6

6

6

62

16-33

Detour Lake Mine NI 43-101 Technical Report

17.0 Recovery Methods 17.1 Process Plant Design The process plant design for the Detour Lake mine has been based on the feasibility study and is described in BBA (2010, 2011, and 2012).

17.2 Process Plant 2013 Results Rate of Milling Production began on January 12, 2013 with the first gold pour occurring on February 18, 2013. Commercial Production was reached on August 12, 2013, after having operated for a period of 60 consecutive days (commencing June 13, 2013) at an average rate of 41,428 tpd. Detour Gold's definition of commercial production stated that commercial production will be declared on the first day of the calendar month following the mill having operated for a period of 60 consecutive days at an average of 75% or more of the designed production capacity, equivalent to 41,250 tpd. The ramp-up of the process plant progressed throughout 2013 having achieved the values indicated in Table 17-1. Figure 17-1 and Figure 17-2 show the progress achieved in 2013. Table 17-1

Process Plant Throughput Average Rates

Q4 2013

Plant Availability 1

%

Q4 2013

Hourly Production

tpoh

2,335

Q4 2013

Daily Production

tpd

37,090

Year

Yearly Production

1

Mt/yr

66

11.2

Availability in October and November averaged 82.5%.

Figure 17-1 Operating Time and Rate of Milling for 2013

4 February 2014

17-1

Recovery Methods

Figure 17-2 Monthly Average Throughput Rates for 2013

By the fourth quarter 2013, the plant was operating at 2,335 tpoh with an average daily production of 37,090 tpd. For short periods of time, the throughput rates reached levels greater than 2,800 tpoh with two days in November 2013 at throughput rates of above 60,000 tpd (highest throughput at 63,700 tpd). Availability (total operating time) The availability reported is calculated by combining the mechanical availability and the operational utilization. In October and November 2013, availability was averaging 82.5%. In December 2013, the failure of the pre-leach thickener torque cage reduced the overall availability for the fourth quarter to 66%. Recovery During 2013, the recovery on a quarterly basis increased from 80% in the first quarter, 82.5% in the second quarter, 84.6% in the third quarter, and 92.2% in the fourth quarter. The ramp up to 92.2% in the fourth quarter is the result of improved stability and utilization of the gravity circuit. When compared to the recovery model used in the feasibility study, the gold recovery obtained during that period was 1% to 3% higher. Consumables The grinding circuit has been designed for higher throughputs than what has been achieved in 2013. These lower milling rates contributed to over-grinding and thus have generally induced higher consumption rates of most reagents.

17-2

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Grinding Media In 2013, the grinding media consumption particularly in the SAG mill has been lower than what was projected in the feasibility study. As the availability of the pre-crushing circuit improves, the grinding media consumption in the SAG mill will decrease further. The increased rate of milling will also contribute to lower 2.5" ball consumption as that rate is largely a function of operating time and final grind size. Cyanide Cyanide consumption for 2013 was in the order of 0.60 kg/t while the expected consumption was to be in the range of 0.36 kg/t. The over-grinding of the ore in 2013 has contributed to the higher addition of cyanide. As well, the copper levels in the ore processed have shown to be higher than projected and contributed to the higher consumption rates of cyanide. The cyanide consumption is expected to decrease to approximately 0.40 kg/t as the process plant stabilizes and further improves. Lime Lime addition presently is to control pH in grinding and in cyanide destruction. The current control strategy for lime in grinding is to reach a pH set point of 11 and above, which will be maintained through leach and into CIP. The addition rate is expected to be reduced to the feasibility study level (Table 13-7). SO2 The cyanide destruction circuit is an Inco SO2/air system. In 2013, the system was supplemented with sodium metabisulphate (“SMBS”) due to logistical issues. The LOM assumes that the SO2 consumption will reduce stoichiometrically with cyanide. Oxygen The present oxygen plant has been sized to deliver 1,462 m3/hr of oxygen above 90% purity.

4 February 2014

17-3

Recovery Methods

17.3 Process Plant LOM Forecast Rate of Milling Ramp-up and optimization will continue through to the end of 2016. In 2017 and beyond, the throughput rate is estimated to reach 2,704 tpoh and 61,000 tpd, resulting in an annual ore processing rate of 22.26 Mt (Table 17-2). Table 17-2

Process Plant Average Throughput Rates Year

2014

2015

2016

2017 to LOM

Plant Availability

%

86.6

91.2

93

94

Hourly Production

tph

2,500

2,510

2,615

2,704

Daily Production

tpd

52,000

55,000

58,000

61,000

Yearly Production

Mt/yr

18.95

20.05

21.30

22.26

Availability (total operating time) From 2014 to 2017, the availability is expected to improve progressively from 86.6% to 94%. Unplanned downtime is expected to decrease as maintenance focusses towards preventative and predictive maintenance programs. Streamlining the planned shutdowns will assist in the overall strategy to decrease the downtime and improve the overall availability. Operation downtime is expected to decrease as operational personnel gain experience over the next few years. Recovery From 2014 through to 2016, the operation is expected to continue its ramp-up to ultimately an estimated 61,000 tpd. During this time period, the operation will be stabilized through optimization and improvements in various areas. There is still upside in gold recovery as improvements will be focused on:

17-4



Solution gold losses;



Gravity circuit stability;



Oxygen stability in leaching;



Cyanide stability in leaching;



Process control in grinding; and



Reduction of carbon losses in CIP area.

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Consumables Table 17-3 shows the projected reagent consumption rates for the process plant for the year 2014, 2015, 2016 and for the remaining LOM period. Table 17-3

Projected Reagent Consumption Rates (kg/t) 2014

Lime

2015

2016

2017 to LOM

1.15

1.0

0.9

0.9

Caustic Soda

0.035

0.035

0.035

0.035

Anti-Scalant

0.027

0.027

0.027

0.027

Cyanide

0.55

0.5

0.45

0.4

Copper Sulphate

0.07

0.05

0.05

0.05

SMBS

0.28

0.28

0

0

Flocculent

0.02

0.02

0.02

0.02

Grinding Media 2.5"

0.47

0.45

0.4

0.4

Grinding Media 5"

0.47

0.45

0.4

0.4

Cyanide Detox Carbon

0.43

0.29

0.19

0.19

0.038

0.035

0.018

0.018

Grinding Media The consumption of grinding media on a per tonne basis is expected to decrease from a combined level of 0.95 kg/t to 0.8 kg/t from 2014 to 2016. Over this period, the tonnage of the process plant is expected to increase. With the tonnage currently below the design level, the grinding circuit product size is finer than the levels projected in the design. As the tonnage of the circuit reaches the design capacity, the product size of the grinding circuit is expected to reach design level. At that point, the grinding circuit is expected to become more efficient in the use of energy and grinding media. It is also expected that during this period the operation of the secondary crushers will be optimized, which will likely improve the stability and efficiency of the grinding circuit. Cyanide The consumption of cyanide is expected to decrease from 0.55 kg/t in 2014 to 0.40 kg/t by 2017 and is expected to remain at this level for the remainder of the LOM. The cyanide use will be optimized with the use of online cyanide analyzers and experience gained from operating the circuit. Lime Currently, lime is only added to the pre-leach thickener. Lime addition points will be added in the leach circuit to optimize lime addition by allowing a better degree of control of the pH in the circuit. It is expected that the lime addition rate will decrease to 0.9 kg/t by 2016.

4 February 2014

17-5

Recovery Methods

SO2 Cyanide levels will be reduced in leach therefore reducing the SO2 consumption over the LOM. Also, sustaining capital was assigned to implement projects to reduce SO2 consumption and operating cost. Oxygen A second oxygen plant will be installed in 2014 to stabilize and maintain optimum dissolved oxygen levels in leach. Additional dissolved oxygen probes will also be installed in the leach circuit. These changes will allow for the oxygen addition to the circuit to be balanced for optimal leach kinetics as the tonnage of the plant increases over the period from 2014 to 2017.

17.4 Debottlenecking The Detour Lake process plant is designed for 55,000 tpd at 92% availability with the intent to increase to 61,000 tpd at 94% availability (i.e. the front end of the process plant is designed for 2,700 tpoh). Starting in 2014, a debottlenecking and operation optimization exercise will be initiated to increase the production throughput to an estimated 61,000 tpd from 2017 onwards. The main elements currently forecasted to support the optimization include: 1. Modification to primary crusher conveyor: The primary crusher conveyor will be split to provide initial sacrificial belt. This will reduce complexity and improve availability. 2. Installation of second oxygen plant: This will provide more oxygen delivery to the leach and give greater stabilization and control of dissolved oxygen in the leach circuit, resulting in better conditions required for gold dissolution. It will also help to support the cyanide control strategy. 3. Installation of up to two additional cyanide destruction tanks: The addition of two more tanks will provide increased residence time and give better buffering capability when circuit upsets occur. The first tank will be installed in 2014 and further evaluations will determine if the second tank is necessary. This will result in more sustainable production throughputs while obtaining better cyanide detoxification. 4. Installation of additional leach tanks: The addition of leach tanks will be considered for 2016 and 2017 in the event that the addition of oxygen does not lead to the kinetic improvement expected (the sustaining capital assumes the addition of 4 leach tanks). 5. Pumping capacities: Pumping capacities will be re-evaluated annually from 20142017.

17-6

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

The expenses completed in 2014 are mostly meant to reduce operating cost, increase availability and add robustness to the recovery process; nevertheless, they will also be designed to cope with the estimated higher tonnage rate. The full scope of debottlenecking and optimization will be finalized in 2014 when the plant has a longer period of time at higher throughput. Some of these modifications are also assuming a favourable gold price environment and could be delayed should the overall economics not support the investment. Figure 17-3 outlines the process flow diagram for the process plant and Figure 17-4 shows a general layout of the process plant.

4 February 2014

17-7

Recovery Methods

Figure 17-3 Simplified Process Flowsheet

17-8

4 February 2014

Recovery Methods

Figure 17-4 Process Plant General Layout

17-10

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

17.5 Tailings and Water Management The selected site of the TMA is located in the east part of the Detour Lake mine and follows the design from the feasibility study with adjustments based on the observed performance in 2013. The TMA development plan to accommodate the future tailings production consists of augmenting the storage capacity of the existing TMA (referred to as Cell 1) and create new cells (Cell 2 and Cell 3) immediately north and south of Cell 1, respectively. Cells 1, 2 and 3 are developed sequentially for tailings and water management. A simple layout of the TMA cells is presented in Figure 17-5. Figure 17-5 Simple Layout of TMA Cells

The TMA will also serve as the central water management facility for local runoff, tailings slurry water and the open pit water, with water reclaimed for mill operation. The TMA for the feasibility study was initially designed for a total storage capacity of approximately 260 Mm3 (363 Mt) with potential for additional raises and/or expansion to accommodate additional capacity as required. During 2013, an evaluation of TMA expansion alternatives determined that approximately 204Mm3 (287 Mt) of incremental tailings produced from the increased (updated) reserves and resources can be accommodated in the TMA with minor changes to the footprint, height and final closure 4 February 2014

17-11

Recovery Methods

concepts as outlined in the feasibility study. Accordingly, the total tailings capacity within the current design framework is 464 Mm3 (650 Mt). This exceeds the tonnage of Proven and Probable reserves on which this LOM plan is based. Expansion alternatives include increasing the height of the deposited tailings in all three cells, increasing and slightly realigning Cell 2 only, or a combination of these and other methods. Estimates for the additional sustaining capital costs to accommodate reserve tonnage have been included as part of the financial analysis. Also during 2013, Detour Gold obtained approval from the MNDM to construct the tailings dams using a ‘centerline’ method rather than the originally proposed ‘downstream’ method to reduce NAG rock haulage quantity and corresponding costs 17.5.1 TMA Design Criteria and Deposition Plan (feasibility study) The following are basic assumptions underlying the design of the TMA: 

No long-term geochemical impacts to groundwater or surface waters are expected (refer to section 20.2.3);



A cyanide destruction plant operates at the plant site to treat the tailings slurry;



Runoff and seepage inflow water from the open pit is collected and discharged into the TMA. This water may contain elevated concentrations of ammonia generated from blasting operation at the open pit. Adequate retention time in a separate cell in the TMA allows natural aging for the natural destruction of this ammonia to allow discharge (if any) of this water, if needed, to maintain the water balance;



Sub-aerial method of deposition is considered suitable for the mine in view of the expected geochemical characteristics of the tailings; and



The conventional slurry disposal method proposed is operationally simple with low maintenance.

In the original TMA design, the following operational parameters were applied: 

Approximately 347 Mt of tailings to be produced during the LOM;



The tailings to be produced at a rate of 55,000 tpd then 61,000 tpd during the estimated operational LOM;



The tailings to be transported from the plant site through a surface pipeline to the TMA. The tailings to be pumped as slurry at an assumed 55% solids content by weight;



The tailings to be deposited mainly by spigotting to form smooth tailings beaches;



Deposit slopes of 1% for sub-aerial and 4% for sub-aqueous conditions based on AMEC’s experience with similar gold tailings deposits; and



Average settled dry density of tailings is 1.4 t/m3 based on results of geotechnical testing of the tailings and AMEC’s experience with similar gold tailings deposits.

The locations of dams were selected based on the following criteria:  17-12

Minimize the quantity of materials required for construction; and 4 February 2014

Detour Lake Mine NI 43-101 Technical Report



Maximize the tailings storage volume while minimizing the dam height.

The dams are designed for the most severe flood and earthquake criteria, being the probable maximum flood (“PMF”) and the maximum credible earthquake (“MCE”) in accordance with the Ontario Dam Safety Guidelines (ODSG; MNR 1999). The design principles of the dams were developed based on the following considerations: 

The dam to be structurally stable and to be designed to the standards consistent with the hazard classification category and modern dam engineering practice;



The dams to have a low permeability element to provide for efficient water management and impede seepage rates;



Minimizing new disturbance to the environment; the dams to be designed to maximize the use of waste mineral materials, including mine rock and stripped overburden from open pit; and



The dams to be raised in stages to reduce the initial material requirements and capital cost outlay, and to utilize the abundant mine rock produced during operations (and thereby minimizing stockpiling requirements).

The objectives of the deposition plan are to: 

Manage two cell operations for the majority of the LOM with deposition occurring in a single active cell and switching between cells as the storage of the active cell is nearing capacity. This approach simplifies pond water management and balances the dam construction schedule to improve cost control. A third cell will be added in the later part of the operations when the initial two cells are nearing capacity;



Discharge the tailings slurry from the perimeter dams to develop a tailings beach against the dam and form an internal decant pond within each cell. The minimum tailings beach width will be approximately 100 metres at the normal pond level. This arrangement will reduce the seepage losses through the dam foundation and will also accommodate easy access to the decant towers installed for reclaiming water; and



In the final stage of Cell 2 operation, the deposition will occur on a semi-closed perimeter dam to form a “dry” pile and eliminate the internal tailings pond from Cell 2. This will improve stability, and reduce maintenance and monitoring of the tailings impoundment after closure.

17.5.2 Design of TMA Dams During the TMA construction activity in 2013, several opportunities for improvement became evident. The construction program requires both ‘owner’ work and ‘contractor’ work, as well as a combination of construction materials, including chemically inert waste rock from the mine. The change to ‘centerline’ construction allows the total quantity of waste rock to be deferred and reduced, effectively decoupling TMA construction requirements from the mining sequence. Further, the ‘centerline’ construction reduces the required quantities for the relatively expensive filter/drainage materials. Key elements of 4 February 2014

17-13

Recovery Methods

centerline construction (compared to downstream construction) are shown in Figure 17-6 and Figure 17-7. Figure 17-6 TMA Downstream Construction

Figure 17-7 TMA Centerline Construction

The design features of the Cell 1 dam are: 

A relatively low permeability starter dam constructed of till stripped from the open pit development and facilitate the integration of the existing historical tailings dams;



A sand blanket drain under the downstream portion of the starter dam;



A twenty metre dam crest width to provide sufficient space for operating the tailings slurry pipeline and ease of construction, as well as to minimize fill quantity and therefore reduce capital costs;



2H:1V upstream and downstream slopes for stability and to minimize slope erosion;



Riprap erosion protection on the upstream slope to protect against erosion from precipitation runoff and wave action in the event of the tailings pond residing temporarily against the embankment during the early deposition period;



Subsequent raises of the dam comprise: 

17-14

A till core zone to inhibit seepage;

4 February 2014

Detour Lake Mine NI 43-101 Technical Report



The downstream shell of the dam is constructed of inert mine rock blasted from the open pit mine operations (Zone 4 and Zone 5) to reduce construction costs and optimize scheduling; and



Sand and gravel filter and crushed rock transition zones between the till and the rockfill.



The dams are founded on prepared foundations;



Stability analyses were carried out for critical sections of the dams along the perimeter of Cells 1, 2 and 3, and the estimated factors of safety for short term, long term and pseudo-static analyses satisfy the minimum factor of safety requirements of 1.3, 1.5 and 1.1, respectively. The design change from ‘downstream’ to ‘centerline’ construction does not change the factors of safety; and



Seepage analyses were carried out for selected sections of the dams for Cell 1 and Cell 2 and the estimated seepage values have been included in the water balance. The design change from downstream to centerline construction involves a thicker core, which is projected to result in reduced seepage.

17.5.3 TMA Water Management The TMA serves as the central water management facility for local runoff, tailings slurry water and the open pit water, with water reclaimed for mill operation. The objectives of the water management are to: 

Provide adequate retention time for control of total suspended solids prior to reclaiming water for mill use;



Maximize reclaim water volume for mill operations;



Allow for natural destruction of ammonia in a separate mine water pond if and when effluent discharge to the environment is required; and



Handle upset conditions and/or runoff generated from major storm events.

Water is currently reclaimed back to the process plant site continuously for processing needs using a decant tower with pumping facilities located in the tailings pond. The mill water reclaim rate from the TMA is about 92% of the tailings slurry discharge water volume (approximately 43,000 m3/day at full production rate of 55,000 tpd). Make-up water sources for mill operations are the existing flooded open pit (available 2014), groundwater seepage into the mine and East Lake. A comprehensive water balance has been developed to track all fresh and waste water flows to ensure that appropriate management is planned for each type of water and to avoid mixing contaminated water with relatively clean water. Water balance models have been developed for the average, wet and dry runoff conditions. This plan also ensures that adequate quantities of fresh and process water are available for the camp and operations needs respectively. All plant site surface drainage is collected in a series of ditches and ponds for recovery of all water for routing to the TMA. Water outside of this drainage system will continue to flow 4 February 2014

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Recovery Methods

to the peripheral local natural drainage and not have any impact on the local surface or groundwater regimes. The drainage from the process plant site and each of the waste rock piles are collected in a series of ditches and ponds and are also routed to the TMA. This minimizes any major seepage to the groundwater. The proactive management of water issues starts with developing prevention measures into the design of the tailings facilities. The following strategies have been adopted to reduce the risk of contaminants entering the local groundwater or surface water regimes: 

The milling includes a final process step to destroy cyanide to very low levels in the tailings before it is pumped to the TMA;



TMA seepage Collection ditches have been installed at the base of Cell 1 with pumps installed to recycle the water back to the TMA; Ditches and pumps will be installed for Cells 2 and 3 when required;



While operating only in Cell 1, no effluent discharge from the TMA is required. When a second cell is constructed and the site water balance indicates surplus water accumulation, the tailings water and mine water will be kept in separate cells as they have very different water quality. This will allow easier treatment of any effluent that needs to be discharged to the environment under the terms of the MOE operating permit.

The key considerations for design and operation of the water management system are: 

The minewater contains suspended solids, traces of ammonia and nitrate, and potential traces of dissolved metals;



The tailings contain suspended solids, dissolved metals from the leaching process, traces of cyanide after the destruction process and the decomposition products of cyanate (CNO), thiocyanate (SCN) and ammonia, which will decompose over time but will require extended time periods to achieve the desired concentration; and



The minewater can be naturally treated in one of the cells to settle the suspended solids and decompose the traces of ammonia and nitrate (from explosives). Following this natural treatment, the pond water is predicted to meet the permit effluent discharge criteria and may be discharged to the receiving environment during the fall months, if needed, to maintain the water balance.

The sequence of use and type of water deposited in each is shown in Figure 17-8.

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Detour Lake Mine NI 43-101 Technical Report

Figure 17-8 Schedule for Water Management

Tailings

Tailings

Cell 1

Mine Water

Cell 3 2014 ‐ 2019

Mine Water

Cell 2

Cell 2

Cell 1

Mine Water

Cell 1

Cell 3

Tailings

Cell 3

2019 ‐ 2031

2031 ‐ 2035

The first tailings were deposited in Cell 1 and the mine water will initially be deposited into Cell 1 to start the mine and then into Cell 3. It is anticipated that Cell 3 will be ready to receive water in 2015. Cell 2 will receive tailings for years 2019 to 2031. Cell 3 will receive tailings for the last stage of the mine. The mine water pond will also be rotated as per the above figure. In Years 1 through 6, there will be no water released from the TMA under normal climatic conditions. In subsequent time periods, if excess water exists in the system it will be pumped from the water management cell to the East Lake from September 1 to December 31. As illustrated in Figure 17-8, the mine water cell varies as the mine evolves and uses a previous tailings cell where significant aging will yield an effluent which meets the MOE permit, and can therefore be discharged. The TMA will be designed to contain runoff resulting from an Environmental Design Flood (“EDF”). The EDF is selected as the 1:100 year January 1 to August 31 maximum runoff; the runoff accumulation period with no discharge to the environment. The TMA is designed for ‘no-discharge’ under this condition. Following an EDF event, the elevated water ponds in the TMA will need to be returned to normal operating levels by means of discharging more water to the environment if water quality is acceptable for release. Under a drought condition of two historical consecutive dry years, the TMA will have sufficient water to supply the continuous mill reclaim requirement. The seasonal discharge to the environment (if any) will be reduced. The TMA will have sufficient freeboard to safely pass the runoff resulting from the Inflow Design Flood ("IDF") through the emergency spillway. The IDF is the 24-hour PMF event. The discharge from the spillways will be directed to towards the watershed of East Lake which flows into the Detour River system and north to Hudson Bay. In the two-cell system of deposition and dam raises, one cell will be lower than the other cell. In the event of an IDF, overflow can occur from the higher cell into the lower cell via the swale (i.e. internal spillway) at the narrows of the TMA. Thus, a minimum of one exterior emergency spillway at Cell 1 will be provided to handle storm events from both Cells 1 and 2 at every stage of operation. A second exterior emergency spillway will be constructed specifically for Cell 3 when it is developed early in the mine life. The spillways will be raised in stages and at strategic locations. 4 February 2014

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Recovery Methods

17.5.4 Geotechnical Design of the Mine Rock and Overburden Stockpiles Mining operations will generate stripped overburden and blasted mine rock, while a portion of these materials will be used for the construction of the tailings dams and plant site facilities. The net quantity of mine rock and overburden will be stored in on-land stockpiles. The configuration of the stockpiles is described in subsections 17.5.5 and 17.5.6, respectively. The geochemistry of the mine rock and the water management of the stockpiles are described in section 20.2. The stockpile boundaries are constrained principally by: 

A minimum setback of 120 metres from any tributaries, creeks and water bodies;



A setback of 100 metres from the final toe of the proposed tailings dams;



A setback of 100 metres from northeast extent of the existing domestic landfill to allow for potential future expansion of the facility and to avoid undermining of the stability of the future mine rock stockpile;



A setback of 50 metres from mine roads and infrastructure; and



A minimum setback of 200 metres from the open pit perimeter was assumed in the study.

17.5.5 Mine Rock Stockpiles The final exterior slopes will have an overall 2H:1V slope and may require the construction of a shear key if soft clay deposits are present, to satisfy the minimum factor of safety requirements of 1.5 and 1.1 for stability under long term and pseudo-static loading conditions, respectively. The conceptual design of the shear key size requirement and the construction methodology of the mine stockpiles are detailed in the Tailings, Mine Rock and Overburden Management Feasibility Design Update Report (AMEC, 2010a) to manage stability of the stockpile constructed over soft clay foundations. Additional field studies are planned to assess these foundation areas to finalize the design of these stockpiles. 17.5.6 Overburden Stockpiles Stability analyses were carried out for a 45 metre high stockpile section with an overall slope of 5H:1V. The calculated factors of safety for long term and pseudo-static analyses satisfy the minimum factor of safety requirements of 1.5 and 1.1, respectively. Depending on the performance of the wet and soft overburden materials during placement, flatter slopes may be expected. If the silty clay material is too soft and tends to flow, it may be necessary to contain it within the coarser silt-sand or till dumps. 17.5.7 Performance Monitoring Inspection and monitoring will be performed during construction and operation of the dams and waste stockpiles to assess their performance and safety; and to verify that actual conditions are consistent with the design assumptions and intentions. Inspection 17-18

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and monitoring will also optimize maintenance and repair costs, provide warning of potential impending risks, and provide sufficient time to implement remedial measures, if required.

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Detour Lake Mine NI 43-101 Technical Report

18.0 Infrastructure 18.1 Site Resources and Infrastructure The region benefits from a strong contractor and supplier base to the mining industry. Skilled labour and suppliers are readily available in the nearby towns of Cochrane, Kapuskasing, Iroquois Falls, Timmins, and Kirkland Lake. The following elements of site infrastructure have already been constructed for the mine operations. 18.1.1 Site Accommodations At the Detour Lake mine site, workers are accommodated in two camps. The ‘Permanent Camp’ is located six kilometres west of the Detour Lake mine in close proximity to Little Hopper Lake. It is comprised of a reception, kitchen, recreational, laundry, and dormitory facilities. The capacity of the ‘Permanent Camp’ is 509 persons while the ‘Construction Camp’ near Sagimeo Lake has a current capacity for approximately 355 persons. Both camps are equipped with suitable wastewater treatment facilities. 18.1.2 Power Supply The 180 kilometre powerline was constructed in two phases during the 2010-2011 winter months. It was installed from the Detour Lake processing plant facility to Island Falls tie point and then to Pinard substation. The Project site was connected to the 230 kV powerline on July 19, 2012. The 230 kV transmission line allows for the distribution of more than 85 MW of power, suitable to service the entire Detour Lake mine operation once in full production. In the event of a power failure, the Project has sufficient emergency power generation for the provision of basic services. 18.1.3 Water Supply Potable water for the ‘Permanent Camp’ is obtained from Little Hopper Lake, adjacent to the Permanent Camp, and processed through a water purification plant. This is adequate for the Detour Lake’s current and future needs. Potable water for the ‘Construction Camp’, mine service facility, site administration facility, and the process plant is obtained from bore hole wells, close to the camp, and processed through a water purification plant. Fresh water is pumped from East Lake. This water is primarily used in the process plant for reagent mixing but is also used as wash water in the truck wash facility and water make-up for the fire water tank. 18.1.4 Processing Plant Facilities The processing plant comprises three main buildings (the primary crushing building, the secondary and pebble crushing building and the main process plant building). Additional process facilities are located adjacent to these buildings. 4 February 2014

18-1

Infrastructure

The primary crushing building is located approximately 450 metres to the northeast of the eastern pit limit. Adjacent to the primary crusher, a ROM stockpile was established to help manage the crusher down time. The crusher building houses the gyratory crusher and the tail end of the stockpile feed conveyor. The crushed ore stockpile has live capacity of approximately 100,000 t. Under the stockpile, two reclaim tunnels were installed for the conveyors to recover the crushed material. Each conveyor reclaims crushed ore from the stockpile to a secondary crusher located in the secondary and pebble crusher building. In this building, a conveyor collects both secondary and pebble secondary crusher undersize to convey the ore to the SAG mill. Both secondary crushers and pebble crushers are equipped with shuttle chutes and bypass chutes to enable maintenance of crushers without stopping a grinding line. The main processing plant building houses the grinding, CIP, gravity & intensive cyanidation, reagents, stripping, electrowinning, refining areas, compressors as well as tailings pumps. The leach tanks are located north of the main process building, between the thickeners. The tanks are arranged in two sets of 10 tanks (4 rows of 5 tanks) on a large containment concrete pad. The process staff offices are located within the main processing plant. This office complex also houses a conference room, lunch room, change rooms, washrooms, documentation room and a metallurgical laboratory. The plant maintenance shops are located on the 1st and 2nd floor of the main processing plant building on the south side of the grinding area. 18.1.5 Tailings Management Area The tailings pond, located approximately two kilometres east-northeast of the open pit, is currently holding approximately 10 Mt of tailings from the former mining operation plus 11.2 Mt processed over 2013. Tailings from ongoing operations at Detour Lake will be accommodated in the current cell and adjacent cells located to the northeast of the processing plant. These cells have been designed to accommodate up to 650 Mt of processed tailings. This exceeds the tonnage of ore in this LOM mine production plan. In order to construct the tailings impoundments required for the current mineral reserves, approximately 78 Mt of clean (non-acid generating or NAG) waste rock will be necessary. This rock will be sourced from the open pit mine. 18.1.6 Waste Rock Facility The mine production plan over the LOM calls for the mining of 1,192 Mt of NAG waste rock. The NAG waste rock not required for the construction of the TMA will be stored in waste dumps. This amount of approximately 1,116 Mt will be placed to the north and south of the Detour Lake open pit. Mining at Detour Lake may expose rock with the potential to generate acid. However, historical mining from the former Detour Lake mine, and ongoing monitoring and sampling of mined materials, supports the view that the impact of PAG rock will be manageable. The quantity of PAG rock in the LOM is estimated at 298 Mt. This material will be stored to the north of the Detour Lake open pit so that in the event of metal leaching, the runoff will be intercepted and managed. 18-2

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Detour Lake Mine NI 43-101 Technical Report

18.1.7 Mineralized Waste Based on the CoG of 0.5 g/t Au, mineralized material with a grade of 0.5 g/t Au or greater will be fed directly to the process plant. Mineralized material with a grade of 0.4-0.5 g/t Au will be stockpiled. Over the LOM, this currently amounts to approximately 108 Mt at a grade of 0.45 g/t Au. In the current LOM plan, this mineralized material is not included in the planned process plant feed. It may however be reclaimed and processed at the end of LOM. Accordingly, it will be placed carefully so as to facilitate its potential future recovery. 18.1.8 Overburden Stockpiles An overburden stockpile with a capacity of approximately 81 Mt will be required to accommodate the overburden at Detour Lake. This main stockpile will be located approximately 2.0 kilometres northwest of the Detour Lake mine. 18.1.9 Explosives Plant Orica Ltd. has constructed a bulk explosives plant approximately 3.5 kilometres west of the processing plant facilities. The nominal capacity of this plant is approximately 30,000 tonnes of explosives per year, which is sufficient to meet the mine’s requirements. 18.1.10

Mine Service Facility

The Detour Lake mine site facilities already include sufficient heavy equipment workshops for the first three years of the mining operations. The Mine Service Facility is located approximately 1.2 kilometres south of the processing plant. An appropriately sized truck wash facility has also been constructed. Site administration facilities have been constructed adjacent to the mine service facility. The administration facilities consist of offices, warehouse, change rooms, and showers. Attached to the administration building is the emergency services area. It contains two offices, an examination room, a treatment room, and a waiting room. Within the same complex, a covered garage houses the ambulance and fire truck. 18.1.11

Site Roads

Sufficient roads have been built to provide general access to all main areas of the mine and processing plant facilities. Additional roads were constructed over 2013 to simplify site access and minimize the potential for light vehicle traffic mixing with heavy equipment (i.e. mining fleet).

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18-3

Infrastructure

18.1.12

Site Communications

A fibre optic link provides internet access to the Detour Lake mine and connects the processing plant, administration facilities, and permanent camp to offices in Cochrane and Toronto. Voice and data is communicated by radio and wireless backbone where the use of the fibre is not practical. Satellite phones are used as emergency backup and for coordinating transportation along the access road. 18.1.13

Site Security

Site access is provided through a guard/security house located at the entrance to the site on the main access road. The guard house is a wood frame building. Visitor car and truck parking bays are provided adjacent to the guard house. The guard house is equipped with radio and telephone communication and is manned continuously. Security maintains a presence throughout the site, covering asset protection and enforcement of site traffic rules.

18.2 Cochrane Facilities Facilities in Cochrane to support the Detour Lake mine include a warehouse, administration offices, and an assay laboratory. SGS Minerals operates the assay laboratory, under a contract agreement with Detour Gold. SGS Minerals agreed to design, build, equip, and operate a full-service analytical laboratory in Cochrane in support of the Detour Gold mine. This laboratory is now in operation and is capable of processing approximately 200,000 samples per year. It operates in accordance with SGS Minerals’ standardized analytical methods and quality control protocols. The contract arrangements also include sample pick-up from the mine. The laboratory operates 365 days per year and 24 hours per day. During periods of accelerated reverse circulation drilling, SGS Minerals has the ability to send samples to its other laboratories for assaying. If necessary, Detour Gold can use other laboratories in the region during peak periods.

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Detour Lake Mine NI 43-101 Technical Report

19.0 Market Studies and Contracts Detour Gold has signed contracts for the secure transportation and refining of its gold production. Under the contract terms, the refiner credits the refined gold and silver to the Company’s account, where it then becomes available for sale. Detour Gold sells its gold production into the market at spot prices or on a forward sales basis. The proceeds from these sales are credited to Detour Gold’s account upon delivery of the gold to the counterparty. The estimated bullion transport costs, liability charges and refining costs used for the financial analysis were based on contract prices agreed with third party contracts.

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Detour Lake Mine NI 43-101 Technical Report

20.0 Environmental Studies, Permitting and Social or Community Impact 20.1 Environmental Studies and Permitting Environmental aspects have figured prominently in the development of the site layout and feasibility study designs for the Detour Lake mine. Environmental considerations were critical to the selection of the preferred alternative for several key project components, including the proposed TMA and other mineral waste storage locations. The potential implications of alternatives were fully considered from an environmental effects and approvals perspective during the design process. 20.1.1 Existing Environmental Conditions The Detour Lake site is located on the northern edge of the Canadian Shield in the Boreal Forest Region of northeastern Ontario close to the Ontario-Québec border. The area experiences cold winters and warm summers. The natural topography of the site is relatively subdued with maximum local relief of about 30 metres. Local site area watersheds tend to be of modest size, generally in the order of 20 to 50 km2, with the principal drainage south to the Detour River, which in turn drains to the Turgeon and Harricanaw Rivers and into James Bay. Vegetation communities comprise a mix of deciduous and coniferous forests and open and treed muskeg, with extensive evidence of forestry operations (by others) in the surrounding terrain. Fish and wildlife species in the area are generally typical of those inhabiting the broader boreal forests of northeastern Ontario. There are no known commercial or recreational fisheries areas proximal to the Detour Lake site. There are a few Federal and Provincial Species-at-Risk that are known to at the mine site or that have a moderate to high probability of occurring on the mine site area. These Species-at-Risk include: Woodland Caribou, Bald Eagle, Rusty Blackbird, Olive-side Flycatcher, Common Nighthawk and Monarch Butterfly. The most notable of these Species-at-Risk is the Woodland Caribou, a species known to appear, at least periodically, in relatively high densities in and around the general vicinity of the mine site area, and is the only Species-at-Risk known or expected to be present that is afforded protected status. Other Species-at-Risk that have a reasonable probability of occurrence within the general Detour Lake area, but were not detected during baseline inventories include the Short-eared Owl, Peregrine Falcon, and Canada Warbler. 20.1.2 Environmental Approval Requirements for Proposed Operations Most mining projects in Canada are reviewed under one or more EA processes. The Federal EA process for Canadian mines is detailed in the Canadian Environmental Assessment Act (“CEAA”). A Federal EA was triggered due to:  4 February 2014

The requirement for an Explosives Factory License under the Explosives Act for a project-dedicated explosives manufacturing factory; and 20-1

Environmental Studies, Permitting and Social or Community Impact



The need for one or more Authorization(s) for Harmful Alteration Disruption or Destruction of Fish Habitat according to the Fisheries Act.

The ‘Project Description’ for Detour Lake was filed with the Federal government in July 2009 and updated in January 2010. A Comprehensive Study Report (“CSR”) was filed with Federal authorities in October 2011 along with supporting documentation; the result of which was the issuance of a letter approving the Project on December 22, 2011 by the Federal Minister of Environment. A follow up program is currently being developed with Natural Resources Canada to track the commitments outlined in the CSR document. Federal environmental approvals were obtained for the construction and operation of specific elements of Detour Lake, as identified in Table 20-1. Table 20-1

Federal Environmental Approvals

Approval / Licence

Agency Responsible

Description

Licence for an Explosives Factory (and Magazine) Explosives Act

Natural Resources Canada

Construction and operation of an explosives factory and magazine(s).

Authorization(s) for Harmful Alteration Disruption or Destruction of Fish Habitat Fisheries Act

Fisheries and Oceans Canada

Disruption to creeks and ponds supporting fish populations; approval for groundwater dewatering effects.

In addition to Federal Approvals listed in Table 20-1, there is an anticipated requirement for Schedule 2 listings for one small muskeg pond and the drainage areas associated with the south waste rock storage area in accordance with Section 5 requirements of the Metal Mining Effluent Regulation. This small muskeg pond is associated with the planned development of the TMA. All Schedule 2 listings require an Order-in-Council approval. Completion of this process was not required at the start of mining and is now being completed to allow use of the south waste rock storage area in 2014. In regards to the Provincial regulatory processes, four Provincial EAs were approved for the Project:

20-2



July 2010: Ontario Ministry of Environment (“MOE”) Class EA for Electricity Projects, for the diesel power generation required to support the construction phase (AMEC 2010a);



November 2010: Ontario Ministry of Natural Resources (MNR) Class EA for Resource Stewardship and Facility Development Projects, for the construction of facilities off-lease, and for such aspects as on-lease aggregate operations or inwater works (AMEC 2010c);



December 2010: Ontario individual EA for Electricity Projects, for construction of a 230 kV transmission line (AMEC 2010b); and



March 2012: Ontario MOE individual EA for Electricity Projects of 10 MW, for allowing a diesel generated contingency power supply to service the construction needs in the event that the 115 kV power line would not be energized by the third 4 February 2014

Detour Lake Mine NI 43-101 Technical Report

quarter of 2011. With the successful energizing of the powerline in October 2011, these facilities have not been installed. In October 2010, Detour Gold received notice from the Ontario MNDM of its acceptance of the Closure Plan and the associated closure bond for Detour Lake. Table 20-2 summarizes the Provincial approvals that were required for the construction and operation of Detour Lake. The permits required to date to operate and work have been received and others will be obtained as the Detour Lake mine evolves (i.e. the Lake and Rivers Improvement permits to construct the tailings cells 2 and 3). There are no outstanding approvals to impede the continuation of the operation. Table 20-2

Provincial Environmental Approvals

Permit/License/Assessment

Agency Responsible

Description

Status (Received/Pending)

Comprehensive Certificate of Approvals – Air and Noise Environmental Protection Act

MOE

Approval to discharge air emissions and noise

Received

Amendment to Certificate of Approval – Industrial Sewage Works Ontario Water Resources Act

MOE

Approval to treat and discharge effluent (such as for: mine / pit water, TMA)

Received

Certificates of Approval – Industrial Sewage Works Ontario Water Resources Act

MOE

Approval to treat and discharge effluent (such as for: sewage treatment, landfill leachate, oil water separator)

Received

Provisional Certificate of Approval – Waste Disposal Site Environmental Protection Act

MOE

Operation of a landfill and/or waste transfer site

Received

Permits to Take Water Ontario Water Resources Act

MOE

Water taking from surface or ground water (open pit and other sources; Detour River, multiple permits expected to be required)

Received (others as necessary)

Work Permits Public Lands Act / Lakes and Rivers Improvement Act

MNR

Work / construction on Crown land (multiple permits expected to be required)

Received (others as necessary)

Aggregate Permits Aggregate Resources Act

MNR

Approval to develop and operate aggregate pits and quarries

Received

Forest Resource Licenses (Cutting Permit) Crown Forest Sustainability Act

MNR

Clearing of Crown merchantable timber

Received (others as necessary)

Plans and Specifications Approval Lakes and Rivers Improvement Act

MNR

Dams and dikes including those associated with the TMA

Received (others as necessary)

Land Use Permits Public Lands Act

MNR

Tenure for permanent facilities on Crown land (transmission line)

Received

MNDMF

For mine construction / production

Received (updated as per closure regulations)

Approval to construct a transmission line

Received

Closure Plan Mining Act Leave to Construct Ontario Energy Board Act

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OEB

20-3

Environmental Studies, Permitting and Social or Community Impact

20.2 Environmental Impacts and Mitigating Measures The following subsections describe the environmental impacts that the Detour Lake mine may have on the surrounding areas, with regards to human, vegetation, and wildlife interaction; and the mitigating measures taken to control those impacts. 20.2.1 Air Quality and Noise The Detour Lake site is remote from off-property human receptors (permanent and seasonal residences and commercial establishments); hence there are no restrictions on air and noise emissions relative human receptors. Air quality standards, point of impingement guidelines, and ambient air quality criteria specified in O.Reg. 419/05, are, however, applicable to industrial settings including mine sites irrespective of the presence of off-property human receptors. The operating monitoring systems installed, as one of the air permit conditions, are anticipated to demonstrate compliance with these standards and no significant air quality or noise impacts are expected. 20.2.2 Geology and Geochemistry Terrain and surficial geology-related environmental impacts are confined principally to aspects relating to vegetation and wildlife habitat protection and to viewscape considerations during operation and closure, and are discussed with those aspects below. Geochemical testing was conducted on mine rock samples and samples of simulated tailings to assess the metal leaching and acid rock drainage (“MLARD”) potential of mine wastes generated by the Detour Lake mine. Static and kinetic testing was completed on these materials. These tests and analysis of the data are currently ongoing. The trends illustrated to date are summarized as follows:

20-4



The new tailings have neutralization potential ratios (“NPR”) that are in the range where there is a very low chance of acid drainage developing. This is due to the relatively low sulphide levels in the tailings and a significant excess of neutralization material. The monthly operational testing has confirmed these predictions and ongoing monitoring continues to track this area;



The tailings from the previous operations had the potential to generate acid due to higher sulphide levels, but the closure strategy of covering the final exposed surface with a layer of de-sulphidized tailings for some areas and a water cover for the remainder has been successful, as acid drainage is not occurring after 10 years of post-closure. As these tailings are currently being covered by a large quantity of new tailings there is a very low risk of acid drainage from any new or old tailings;



The waste rock testing indicated that approximately 83% of the waste rock has a low potential to generate acid due to NPR values that exceed 1.5. To date, the detailed sampling program implemented during operations has shown that the percentage of this type of rock is much higher than 83%. Ongoing tracking during the mine life will provide additional data for comparison against the results from the original predictions; 4 February 2014

Detour Lake Mine NI 43-101 Technical Report



Approximately 17% of the waste rock was predicted to have the potential to generate acid (potentially acid generating - PAG) as the NPR is less than 1.5. Approximately 9% of the rock have a NPR < 1 and hence has the highest potential to generate acid. Consistent with the preceding point, to date, the quantity of this type of rock is lower than predicted;



Some of the PAG has been reclassified as mineralized waste and is being stored in the north waste rock stockpile (MRS 1), which is the area originally designated for the PAG rock. Some of the mineralize waste is also stored in the north part of the south stockpile as illustrated in Figure 16-36;



A small ROM stockpile of mineralized waste of approximately 5 Mt (19 hectares) has been established adjacent to the primary crusher with effective drainage control and monitoring installed to ensure minimal impact on the environment (Figure 16-36). This ROM pad will also be used for stockpiling higher grade ore to provide feed to the mill;



A second medium grade stockpile is planned immediately south of the mineralized waste ROM pile for storing approximately 9.5 Mt of ore (14 hectares). The schedule for this development has not been confirmed. The appropriate permits and consultation processes will be followed in a timely manner before this facility is built (Figure 16-36); and



In order to ensure that any MLARD can be managed effectively if it occurs, a sampling program associated with the mine grade control has been developed to allow the segregation of all PAG rock in an area of the north waste rock stockpile MSR 1 for easy observation and for collection and treatment of seepage if needed. The non-acid generating (NAG) materials will be deposited in two other waste rock stockpiles located north and south of the pit (Figure 20-1)

The observations of the historic waste rock stockpiles, which were established in the early phases of the former Detour Lake mine, indicated that MLARD had not commenced after 17 years of operation. Further observations over the 10 years of the post closure time period has also shown that these stockpiles have not become reactive and have not produced MLARD. Notably, the sulphide contents and the proportion of PAG rock in the historic stockpiles are generally greater than the current and anticipated waste rock.

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Environmental Studies, Permitting and Social or Community Impact

Figure 20-1 General Site Plan

20-6

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Detour Lake Mine NI 43-101 Technical Report

20.2.3 Groundwater Hydrogeological investigations and related groundwater modeling indicate that groundwater inflows to the open pit are likely to be in the order of 4,200 to 5,000 m3 per day (excluding direct surface runoff) after about Year 2 of open pit development and continuing into later mine life. This volume is relatively modest and compares well with previous rates of underground mine dewatering at the former Detour Lake mine and to other Timmins-area open pits. As one of the operating permit requirements, the hydrogeological model will be revised periodically to reflect the updated pit design. However, appreciable changes are not expected with the cone of influence expected to expand slightly at the end of the mine life as the proposed pit is now slightly longer than the one used in the previous hydrogeological model. There are no local groundwater users in the immediate area that could potentially be affected by groundwater depletion directly linked to open pit development. No significant environmental impacts are currently expected with the proposed pit, after the implementation of proposed mitigation measures. 20.2.4 Surface Water Surface water systems have the potential to be affected by point source mine effluent discharges and mine site area runoff; as well as through groundwater system depletion linked to open pit dewatering, where surface water and groundwater systems are coupled. The principal point source effluents will be mine water discharge from the open pit and the mill tailings slurry (both discharged to the TMA) and from the domestic sewage treatment systems. The current design uses best management practices as well as industry standard treatment technologies to ensure effluent quality. This includes pre-treatment of tailings using the SO2/air process to destroy cyanide before deposition in the tailings ponds. As a result, environmental impacts to surface water are not expected to be significant. The separation of the mine water from the tailing allows a zero discharge strategy to be adopted for tailings. The mine water can be naturally aged to reduce the suspended solids and the ammonia to yield an effluent that can meet the MOE discharge criteria. A seasonal discharge from September 1 to December 31 has been permitted to manage any excess water to maintain the water balance. To date, there has been no discharge from the tailing facility or any of the operations areas. The expansion of the open pit to the west will likely have an impact on Walter Lake, a small shallow lake that drains to the south. In advance of this area being developed, the relevant regulatory processes required will be followed to allow this modification to the mine plan. As experienced with the existing mine, a compensation plan can be developed to replace the impacted fish habitat. The optimum permitting and consultation program will be developed in a timely manner and will include the appropriate compensation for any environmental impacts (Figure 20-1).

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20-7

Environmental Studies, Permitting and Social or Community Impact

This size increase of the pit area is minor compared to the prior pit area and hence the closure strategy for the development of a pit lake for this area remains unchanged. This development is not expected to change the financial assurance costs for closure. 20.2.5 Vegetation and Wildlife Potential impacts to vegetation and wildlife are linked as the principal mine-related impacts to wildlife typically involve habitat alterations. Recommendations to minimize adverse effects to area plants and wildlife include: developing a compact project footprint; maintaining a minimum 120 metres vegetated buffer around watercourses; avoidance of unnecessary disturbance to wetlands; and avoidance of tree clearing during the bird nesting period. In addition, there are a number of habitat and wildlife constraints linked to Species-at-Risk and most notably, Woodland Caribou. Recommendations for the protection of Woodland Caribou include as reasonable: minimizing the overall Project development footprint; avoidance of critical over-wintering habitat; minimization of disturbance to mature upland Black Spruce – Jack Pine forests supporting a high abundance of terrestrial and arboreal lichens (its preferred food source); and minimizing the potential for caribou/vehicular traffic interaction. Protection of Woodland Caribou and Woodland Caribou habitat will be a principal focus of government regulators, non-governmental organizations, and Aboriginal groups. By implementing these measures and other similar measures, the predicted effects to vegetation and wildlife are not considered significant. 20.2.6 Aquatic Resources Development of the Detour Lake site has the potential to adversely affect fisheries and other aquatic resources through the discharge of contaminants and through the displacement or alteration of fish habitat. Minor direct displacement of fish habitat could occur as a result of development of facilities such as the TMA, mine rock and overburden stockpiles, and open pit development. Alteration of fish habitat could potentially occur as a consequence of mine dewatering effects on nearby surface water systems, or through actions that could otherwise block or limit fish movement. Mitigation measures have been followed to limit the potential effects on aquatic resources. In addition, a fish compensation plan was approved by Provincial and Federal regulatory authorities with full consultation with the Aboriginal groups in the Detour Lake area. With these mitigation and compensation plans, the environmental effects are not considered significant. A significant part of the mitigation measures (i.e. development of additional fish habitat) was implemented in 2013 to partially fulfill this permit requirement. Additional fish habitat areas are expected to be developed as the Detour Lake mine progresses to complete this plan. As noted in section 20.2.4, for safety reasons, Walter Lake, a shallow small water lake, is likely to be removed when the open pit expands to its western limit. In advance of this area being developed, the appropriate permit and approval processes will be completed. 20-8

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Detour Lake Mine NI 43-101 Technical Report

As with the previous EA processes that have been completed, public consultation will be conducted to develop the final plans. As part of this process, a fish compensation program will be developed to replace the lost habitat. The experience gained from the fish compensation programs that have been completed to date will be of assistance in ensuring a successful program. 20.2.7 Cultural and Heritage Resources Archaeological investigations were carried out previously for the mine access road associated with the previous operation and more recently as part of baseline investigations. These studies have been updated with Aboriginal participation. Neither Woodland Heritage Services nor White Spruce Archaeology has identified archaeological sites to date that are proximal to the Detour Lake mine or likely to be affected by the mine in any foreseeable manner. The overall potential for encountering cultural heritage or archaeological sites that would conflict with the continued mine development plan is considered to be extremely low.

20.3 Social and Community Impact Socio-economic impacts associated with local communities have been and continue to be overwhelmingly positive. The local communities have expressed strong support for the Detour Lake mine, and particularly by the Town of Cochrane representatives. Overall effects are considered significant and positive. Detour Gold had developed a statement on consultation and a specific consultation plan related to the EA and permitting process. The consultation plan had included input from the local municipalities and potentially impacted communities, and Federal and Provincial government representatives. Government departments/ministries/agencies require that meaningful consultation occurs with the public, Aboriginal groups and the MNO prior to issuing environmental approvals. Detour Gold has worked diligently to establish and maintain cooperative relationships with the local Aboriginal communities. The first phase of the consultation program was completed with local municipalities, business and community-based organizations to introduce Detour Lake and to support the preparation of baseline environmental study reports. This first phase also had a priority and focus given to developing relationships with Aboriginal leadership through negotiation of agreements. The second phase of consultation was also completed and focussed on providing information on the EA process, federal CSR and permitting updates. As Detour Lake has moved to operations, the third phase is one of providing employment, training, and business opportunities information. Since the start of construction, Detour Gold has been committed to providing updates on environmental compliance. The Company has entered into formal agreements described below to facilitate the ongoing consultation and engagement of the Aboriginal communities. The Detour Lake area is within the traditional Treaty land area of the Moose Cree First Nation (“MCFN”), Taykwa Tagamou Nation (“TTN”), and Wahgoshig First Nation (“WFN”). 4 February 2014

20-9

Environmental Studies, Permitting and Social or Community Impact

Treaty 9 covers the lands. To formalize the Detour Gold-Aboriginal community relationship, Impact Benefits Agreements (“IBA”) or similar agreements were finalized with these three groups and ratified by the respective communities. The Métis Nation of Ontario has also asserted Aboriginal interest in the area. In January 2012, the Company, the Métis Nation of Ontario and the Métis Nation of Ontario’s Regional Consultation Committee for the James Bay-Abitibi/Temiscamingue areas finalized an IBA with respect to the development and operation of Detour Lake. These agreements indicate a plan to ensure the impacted Aboriginal groups are involved in the environmental assessment process and are involved in creating training plans and promoting local employment and business opportunities and financial compensation. Each of the Aboriginal groups has experience with mining and resource development and has signed both MOUs and IBAs with local companies.

20.4 Closure and Reclamation Planning and Costs Mine closure of the Detour Lake mine at the end of site operations will be carried out in accordance with O.Reg. 240/00. A closure plan for the entire the Detour Lake mine and financial assurance was accepted by the MNDM. Amendments to the new closure plan arising from changes will be issued if required. The proposed project design, construction, and operating methods have been developed to minimize the environmental footprint. Progressive reclamation of lands and ongoing disposal of surplus materials will be used as possible to manage the site and reduce eventual closure costs. The experience obtained from the previous mine operations of 17 years and the closure period of 10 years has been used to develop the closure plan. To date, the site has not experienced acid rock drainage from the existing mine rock materials although there are minor seeps with slightly elevated contaminants that have minimal detectable impact on the local water systems. As these stockpiles contain rock with much higher levels of sulphide minerals, relative to the current operations, which have not become reactive in the 27 years operational/closure history, there are strong indications that the strategy proposed for segregation of mine waste rock will allow a similar passive system to be established. Once mining ceases, the open pit will be allowed to flood, eventually forming a lake. During the post-closure period, the flooding open pit will provide a water management function to manage site ARD (if any). During pit filling, any contaminated drainage will enter the open pit and would be fully contained. Once the pit fills to the point of overflow, pit drainage would flow by gravity into the adjacent Karel Creek and would have to be managed. Several effective technologies are currently available to manage ARD, in the unlikely event it occurs. Mineralized waste will be deposited within the southern portion of Mine Rock Stockpile #1, adjacent to PAG materials and in the north part of the north waste rock stockpile (Figure 16-36). As such, if not processed at the end of mine operations, drainage from these areas would report to the open pit, along with drainage from the confined PAG materials. Mineralized waste stockpiled in the vicinity of the primary crusher will be isolated from the environment with interception trenches and a water management pond during operations 20-10

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Detour Lake Mine NI 43-101 Technical Report

and after closure. The installation of till covers on these two relatively small piles will duplicate the system successfully used by the previous closure plan for the five small original waste rock piles. The observations of these piles after 10 years of post-closure showed that no leaching or significant drainage was occurring. Drainage from other portions of the two main mine rock stockpiles (north and south piles) would be allowed to flow passively to the environment, as it is expected that this drainage will not contain deleterious substances as defined by the Federal Metal Mines Effluent Regulations (“MMER”). At final closure, islands of overburden cover will be placed to establish a base for stockpile revegetation. Revegetation of the stockpiles will be undertaken using a combination of hydroseeding, seeding and hand planting of shrub/tree seedlings. Experience with several other mine sites has shown that native plant species (herbs, shrubs and trees) will readily invade mine rock stockpiles even if there is no overburden cover, similar to the manner in which plants naturally invade bedrock terrain; but the use of overburden islands will accelerate this process. At closure, the TMA will consist of three large cells. The predictions from the geochemistry assessments have yielded the conclusion that the sulphide content of the tailings will be very low and adequate buffering materials will be present to result in a very low potential for ARD to occur. At closure, overburden will be spread over the exposed tailings and will be seeded to provide erosion/dust control, improved aesthetics and wildlife habitat. The ponds will then be seeded/planted with emergent plant species around their perimeters to minimize erosion and to provide useful wildlife habitat. Dam structures containing the TMA will be designed with adequate factors of safety to provide for overall long-term safety and stability and no additional work is proposed at closure, apart from ongoing inspection and maintenance. Aside from the TMA dams, the only other existing or proposed dam for Detour Lake is the outlet control structure on East Lake. At closure, the weir structures will be sealed or removed and an emergency spillway will be established. To restore fish passage through the East Creek system, the outlet from East Lake will be reconfigured at closure to provide an extended graduated artificial creek bed. Once buildings, machinery, equipment and general infrastructure have been removed, saving those aspects required to complete or monitor mine closure activities, the general plant site area will be rehabilitated by backfilling all foundations and covering the site with an overburden and a vegetation cover. For the heavily compacted areas, a process of scarification and re-grading will be conducted and supplemented by the application of an overburden cover as needed with revegetation. Salvageable machinery, equipment and other materials will be dismantled and taken off site for sale or reuse if economically feasible, or disposed of in a licensed facility onsite or offsite. All local site access roads required for post-closure monitoring, or other access, would be maintained in an operational state until such time as they were no longer needed. Local site roads not required for site access would be scarified and allowed to revegetate naturally.

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20-11

Environmental Studies, Permitting and Social or Community Impact

The 230 kV transmission line would be left intact, until such time as it could be demonstrated that this power source was no longer required. At that time, the transmission line segment from the Detour Lake mine to Island Falls would be dismantled, unless another user takes over responsibility for operation and maintenance of the line. It is assumed that the portion of the 230 kV line between Island Falls and Pinard is to be left in place as part of the regional grid, subject to Hydro One concurrence. Once a decision has been made to permanently close the Detour Lake site, it is anticipated that the major closure activities would be completed within a period of two years, if not already completed progressively. The ongoing environmental monitoring and water management programs are expected to be required until such time as the conditions in the various operating permits are satisfied. These allow for the discharge of the site drainage to the natural environment when it can be demonstrated that site drainage no longer poses a threat to downstream receiving waters. Monitoring of various site aspects, such as water quality, revegetation and TMA dam stability, is planned to continue over an extended period of time and is supported by the financial assurance funds that will have been established over the mine life. 20.4.1 Estimated Mine Closure Costs The estimated costs of mine closure and ongoing monitoring are $69.6 million. The cost of closure has been accounted for in the cash flow at the end of the LOM. Detour Gold is responsible to provide the full amount of the financial assurance, subject to any required or approved changes to the closure plan. There currently are four primary phases that are proposed to trigger the issuance of security bonding. Financial assurance will be submitted to the MNDM prior to the beginning of the associated activities of the phase. Based on the phases, Detour Gold is obligated to make the incremental security bonding arrangements listed in Table 20-3. Table 20-3

Security Bonding Arrangements

Detour Lake mine

20-12

Security Established at Start of Phase

Cumulative Security to Be Held

Status

Pre-construction and Phase 1 – construction

$28,262,000

$28,262,000

Completed

Phase 2 – Start of deposition in TMA cell 1

$5,174,000

$33,436,000

Completed

Phase 3 – Start of deposition in TMA cell 2

$21,328,000

$54,764,000

-

Phase 4 – Start of deposition in TMA cell 3

$14,876,000

$69,640,000

-

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Detour Lake Mine NI 43-101 Technical Report

21.0 Capital and Operating Costs Table 21-1 presents a general summary of key LOM parameters for the first five years (2014-2018) and for the LOM. Table 21-1

LOM Key Parameters

Parameters

Units

5 Year Total

LOM Total

2014 to 2018

2014 to 2035

Total Tonnes Mined

millions

582

2,150

Total Tonnes Milled

millions

105

476

Average Head Grade

g/t Au

0.96

1.02

Average Recovery

%

92.1

92.2

Total Gold Production

oz (000s)

2,992

14,333

Total Ozs Sold1

oz (000s)

2,907

14,037

Total Cost of Sales

$ millions

2,216

10,172

Total Sustaining Capital

$ millions

456

1,143

Total Deferred Stripping

$ millions

226

614

Total Pre-tax Cash Flow

$ millions

886

6,499

Average Total Cash Costs (“TCC”) per oz sold2

$/oz

759

723

Average TCC + Total Capital per oz sold2

$/oz

994

848

21.1 Sustaining Capital Costs A complete review of the sustaining capital required for the LOM has been completed with the experience gained from the first year of operation. Table 21-2 provides a summary of these expenditures for the LOM. Table 21-2

Summary of Sustaining Capital Cost Estimate

Description

Sustaining Capital LOM ($ Million)

Mining

535

Process Plant

126

Tailings Management

454

G&A

28

Total

1,143

Mine Closure

5 years 2014 to 2018 ($ Million) 168

5 years 2019 to 2023 ($ Million)

7 years 2029 to 2035 ($ Million)

69

255

43

71

24

20

11

203

114

70

67

14

8

5

1

456

215

350

122

70

1

Gold ounces sold exclude the 2% royalty paid-in-kind.

2

Refer to the section on Non-IFRS Financial Performance Measures at the end of section 1.

4 February 2014

5 years 2024 to 2028 ($ Million)

70

21-1

Capital and Operating Costs

Sustaining Capital for the Detour Lake mine is summarized for the LOM and for indicative 5 year periods (with the exception of the last period at 7 years). Sustaining capital cost estimates are driven by mining fleet expansions during 2014 to 2018 and mining equipment replacements over 2024 to 2029. TMA costs decrease during the period 2024 to 2035 because the base of all three cells will have been completed. Mining The sustaining capital required for the mining fleet is estimated at $535 million over the LOM. It includes the new equipment required to increase the mine production, the replacement equipment for the mining fleet and infrastructure required to maintain the equipment. The assumptions used for the replacement are described in section 16. Process Plant The sustaining capital for the process plant is estimated at $126 million for the LOM. Most of the costs are expected within the first four years in order to complete the debottlenecking efforts and optimization to bring the capacity of the process plant to 22.3 Mt/year and to reduce the operating costs. The debottlenecking exercise will be initiated in 2014 and is expected to be completed in 2017. The sustaining capital cost for the debottlenecking and optimization exercise has been estimated between $45 and $65 million over a four-year period but the higher value has been retained for the LOM. The final scope will be refined in 2014, along with timing of the tonnage increase, which in the LOM has been estimated to improve production in the middle of 2016. General and Administration The sustaining capital for general and administration (G&A) consists of items such as IT, supply chain and security systems and is estimated at $28 million over the LOM. TMA The sustaining capital for additional tailings storage is estimated at $454 million over the LOM. The estimate is derived from existing earthworks contract rates and estimates of self-executed earthworks. The reduction in the capital requirement compared to the 2011-2014 costs is derived from two sources. Firstly, starting in 2014, the design will move to a ‘centre-line’ construction and the volume of material needed for this configuration will be reduced significantly. Secondly, the execution plan will move from a contractor’s execution to a hybrid (contractor-owner execution) and finally to a complete self-execution. This approach allows an execution strategy that reduces the execution risk while realizing cost reduction objectives. The main advantage of self-execution (when and where applicable) is that it takes advantage of much larger mining equipment and avoids the costly double handling needed when executing with smaller equipment. 21-2

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Detour Lake Mine NI 43-101 Technical Report

For 2014, the sustaining cost estimate is still based on contractor’s execution but consideration is being given to an immediate move to a hybrid solution and to that effect, a second excavator (CAT 6030) was ordered for delivery in the second quarter of 2014.

21.2 Deferred Stripping From an accounting perspective, stripping costs which provide probable future economic benefits, provide identifiable improved access to the ore body and which can be measured reliably are capitalized. Detour Gold has applied deferred stripping in the financial model and it resulted in the capitalization of $614 million of mining operating costs over the LOM.

21.3 Operating Costs The operating cost estimate of the Detour Lake operation covers mining, ore processing, tailings and water management, general and administration (G&A) as well as infrastructure and services. Over the LOM, operating costs were estimated from a combination of experience gained in 2013 and first principles. Mining costs were estimated from equipment fleet requirements and the associated labour, fuel and other consumables, which arose from physicals. Processing costs were estimated from throughput, ore characteristics, energy, labour and consumables costs. G&A were estimated from the current camp requirements and the Cochrane office based costs. The LOM assumptions are summarized in Table 21-3. Table 21-3

LOM Economic Assumptions 2014

2015

2016

2017

2018

2019

2020+

Gold Price (US$/oz)

1,200

1,200

1,200

1,200

1,200

1,200

1,200

Gold Price($/oz)

1,260

1,284

1,296

1,320

1,320

1,320

1,320

20

20

20

20

20

20

20

Exchange Rate (US$/Cdn$)

1.05

1.07

1.08

1.10

1.10

1.10

1.10

Electricity ($/kWh)

0.05

0.05

0.05

0.05

0.05

0.05

0.08

Diesel Fuel ($/litre)

0.95

0.95

0.95

0.95

0.95

0.95

0.95

Silver ($/oz)

Total cash costs per ounce of gold sold2 are projected to average $723 over the LOM (Table 21-4).

2

Refer to the section on Non-IFRS Financial Performance Measures at the end of section 1.

4 February 2014

21-3

Capital and Operating Costs

Table 21-4

LOM Total Cash Costs

Mining Costs

$/t milled

$/t mined

$/oz Sold2

11.55

2.56

392

Processing Costs

7.82

266

General and Administration

2.44

83

21.81

741

Sub-Total 3

Other Adjustments

(18)

Total Cash Costs (LOM)

723

21.4 Mining Operating Costs The mining operating costs for the Detour Lake mine are divided into five categories: 

Equipment maintenance;



Fuel and electricity consumption;



Blasting costs;



Personnel requirements; and



Mine general services.

Over the LOM, the average mining operating cost is estimated $2.56/t mined, and $11.55/t milled. Table 21-5 highlights the estimated mining costs over the LOM. Figure 21-1 presents the LOM plan, mining rate and unit mining cost. Table 21-5

LOM Estimated Mining Costs

Activity

2

Total ($/t Ore and Waste)

Equipment Maintenance Costs

$0.93

Equipment Fuel + Electricity Costs

$0.63

Blasting Costs

$0.23

Personnel Costs

$0.59

Services Costs

$0.18

Total Cost per Tonne Mined (LOM)

$2.56

Refer to the section on Non-IFRS Financial Performance Measures at the end of section 1.

3

Other adjustments include costs for deferred stripping, agreements with Aboriginal communities, refining charges and are net of silver by-product credits. 21-4

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Detour Lake Mine NI 43-101 Technical Report

Figure 21-1 LOM Plan – Mining Rate and Unit Mining Cost

21.5 Processing Costs An update of the operating cost estimate for the process plant has been prepared and is largely based on the operating expenditures for 2013, as well as the feasibility study. Through to 2017, the rate of milling will be optimized to 61,000 tpd. The main differences between the present estimate and the estimate from the prior technical report (BBA, 2012) are increases in manpower, a decrease in the electricity price from 2014-2019 inclusive, and increase in maintenance costs. There are also differences in the cyanide and grinding media consumptions between the BBA (2012) estimates, however these differences largely cancel each other. The estimated average annual operating costs for the process plant are summarized in Table 21-6. Debottlenecking and optimizing is expected to continue in 2017 to stabilize the operation to reach the target throughput of 61,000 tpd. This rate will be maintained for the remainder of the LOM. Unit operating costs for the process plant, together with tonnes processed per year and G&A unit operating costs are presented in Figure 21-2.

4 February 2014

21-5

Capital and Operating Costs

Figure 21-2 LOM Processing Rate and Unit Costs – Process and G&A

Table 21-6

LOM Estimated Process Plant Costs

Category

$/t

Manpower (operations and maintenance)

0.94

Electrical Power

2.13

Consumables (incl. reagents and grinding media)

3.12

Maintenance Parts (incl. liners)

1.63

Total Cost per Tonne Milled (LOM)

7.82

21.5.1 Plant Operating Manpower Operating manpower is expected to reduce from current level and stabilize in 2018. The estimated average manpower cost for process plant operations over the LOM is $0.39/tonne milled. 21.5.2 Plant Electricity Costs The electricity consumption for the process plant is expected to be 32.0 kWh/t in 2014. It is then expected to decrease slightly over the next two years as the tonnage and availability increase and while the grinding mills are optimized to utilize power more efficiently. In 2017, the availability of the plant is expected to increase to 94% when the plant is expected to be at full capacity. From this point onward it is estimated that the unit consumption will be 29.5 kWh/t.

21-6

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Detour Lake Mine NI 43-101 Technical Report

Detour Gold has secured a power price of $0.05/kWh for the years 2014 to 2019, inclusive. From 2020 onward, an electricity price of $0.08/kWh was assumed. The average estimated LOM electricity cost for the process plant is $2.13/tonne milled. 21.5.3 Plant Consumables Costs A breakdown of the cost for the major plant consumables is presented in Table 21-7. Liners are included in the maintenance cost category (refer to section 21.5.4). Table 21-7

LOM Estimated Plant Consumable Costs

Category

$/t

Cyanide + Cyanide Detox

1.04

Other Reagents

0.76

Grinding Media

1.11

Other Operations Supplies/Services

0.21

Total (LOM)

3.12

Cyanide consumption is expected to be 0.55 kg/t in 2014 and optimized to 0.40 kg/t by 2017, where it will remain for the remainder of the LOM. The cost to detoxify cyanide will match the reduced cyanide consumption (stoichiometrically) and will therefore reduce over time. The cost per tonne of other reagents such as flocculent, caustic soda, oxygen, and anti-scalant is expected to remain constant from 2014 onward. Based on 2013 operating experience, it is estimated that the consumption of total grinding media will ramp down from 0.95 kg/t to 0.80 kg/t combined for both SAG and ball mill from 2014 to 2017. The grinding media consumption is expected to remain at this level for the remainder of the LOM. 21.5.4 Process Plant Maintenance Costs The average estimated costs for process plant maintenance are presented in Table 21-8. Table 21-8

LOM Estimated Plant Maintenance Costs

Category

$/t

Maintenance Manpower

0.55

Contractors

0.24

Liners

0.47

Other Maintenance Parts/Services

0.92

Total (LOM)

2.18

Manpower for maintenance is expected to stabilize in 2015. Operating experience in 2013 has formed the basis for liner cost estimates. The cost for mill and crusher liners is expected to decrease each year to 2017 from $0.72/t in 2014 to $0.46/t in 2015 and remain at this level for the LOM. The optimization of the liners will contribute to the 94% availability in 2017. 4 February 2014

21-7

Capital and Operating Costs

As well, 2013 operating experience has provided the background to build a detailed estimate of maintenance parts and services. The main items included in this estimate are mechanical and electrical replacement components, oil, grease and lubricants. The total cost of these items was estimated to be $1.18/t milled for 2014 and decreased to $0.90/t milled in 2017. It is assumed that onward the cost will remain constant until the end of the LOM.

21.6 General and Administration Costs The G&A costs include all materials and personnel costs associated with the site administration and infrastructure support. Costs consist of those related to site ‘infrastructure’, ‘camp’ and ‘non-camp’. Infrastructure includes items such as site security, IT, transportation etc. The approximate cost for infrastructure for one year is $24.5 million. Camp costs include food, laundry, accommodation, and related services. Annual costs vary from approximately $11 million in years 2014 and 2015, to a maximum of $15 million in years with peak mining activity. At the end of the LOM, G&A camp costs drop in accordance with decreasing tonnage. G&A non-camp costs include Cochrane based activities such as accounting, human resources, in-bound logistics and supply chain. Such costs amount to approximately $17.5 million. The G&A costs over the LOM are estimated to average $2.44/t milled (Table 21-9). Table 21-9

LOM Estimated General and Administration Costs

Category

$/t

Infrastructure

1.14

G & A – “Camp”

0.49

G & A – “non-Camp”

0.81

Total (LOM)

2.44

21.7 Commercial Production Detour Gold declared commercial gold production on September 1, 2013 (defined as the first day of the month following the mill having operated for a period of 60 consecutive days at an average of 75% or more of the designed production capacity equivalent to 41,250 tpd).

21-8

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Detour Lake Mine NI 43-101 Technical Report

22.0 Economic Analysis 22.1 Economic Analysis The Detour Lake mine LOM economics estimate is based on the 2013 year-end mineral reserves. 22.1.1 Assumptions For the gold price assumptions, Detour Gold and BBA reviewed a consensus survey undertaken by a leading Canadian financial firm, which compiled commodity prices forecast from approximately 25 financial institutions. This survey dated December 31, 2013 was used to establish a base case gold price assumption of US$1,200/oz for all years. For the silver price assumptions, the same survey was used to set a base case silver price assumption of $20/oz for all years. The parameters used for the economic analysis are as follows: 

A US$ gold price of $1,200/oz for all years, providing a degree of conservatism over the consensus long-term nominal price of US$ 1,325/oz;



A Cdn$ silver price of $20/oz for all years, providing a degree of conservatism over the consensus long-term nominal price of US$22/oz;



No inflation differential was provided for, as the cash flow projection uses constant money terms throughout (except as noted);



A residual NSR of two percent (2%) of the net value of gold production was deducted from gold production to derive gold ounces available for sale to Detour Gold’s account; and



Exchange rates of US$ to Cdn$ (based on average consensus rates): 2014

1.05

2015

1.07

2016

1.08

2017 and beyond

1.10

22.1.2 Taxation The Detour Lake mine is subject to the taxation rules and regulations of the Federal and Provincial governments contained in the Income Tax Act (Canada), Corporations Tax Act (Ontario), and the Ontario Mining Tax Act. Ontario Provincial income tax was harmonized with the Federal rules several years ago, except for various credits and/or minimum taxes that are province specific, i.e. Ontario Resource Tax Credit and Corporate Minimum Tax.

4 February 2014

22-1

Economic Analysis

Federal and Provincial Canadian Federal and Ontario Provincial income taxes were computed using tax rates expected during years when the Detour Lake mine is forecast to be taxable and in production (with a combined Federal and Provincial rate of 25%). Detour Lake mine’s past Canadian Exploration Expenses (“CEE”) and Canadian Development Expenditures (“CDE”) and losses carried forward (“LCF”), including 2013 costs incurred through to commencement of commercial production for tax purposes were taken into account as follows: CEE of $405 million, CDE of $97 million, depreciable property of $1.48 billion and LCF of $234 million. The development expenditures, including equipment, have been assumed to fall into the following categories for purposes of claiming the subsequent tax deductions: Pre-production expenditures

CEE and Class 41(a)

Sustaining capital expenditures

Class 41(b)

100% 25%

The depreciable property falls within the Capital Cost Allowance (“CCA”) category 41(a), is deductible at 100%, and is limited to the profit of the mine. The ability to claim CEE in any year is subject to a similar test, i.e. no loss can be attributable to claiming CEE. Any sales, prior to the commencement of commercial production for tax purposes, reduces the amount of available CEE in that period. Over the LOM, Federal and Provincial income taxes have been estimated at $1,038 million. The use of LCFs to reduce the overall Federal and Provincial income taxes payable may not be applicable to all users of this report due to the user’s tax profile, as these amounts were generated primarily through corporate G&A, corporate exploration and interest expense accumulated from the company’s inception. The usage of LCFs in the LOM financial model reduced income taxes payable by approximately $50 million. Recent changes announced in the 2013 Federal budget, now substantially enacted, impacting the Canadian Federal and Ontario Provincial income tax treatment of the accelerated depreciation allowance for pre-production mining & processing assets as well as pre-production development expenditures will have no impact on Detour Gold’s LOM tax computation due to the grandfathering provisions contained within the budget for mines already in development when the proposals were announced. Post commercial production, for tax purposes, sustaining capital expenditures and additional costs for expanding the pit, if any, are treated in a similar manner both before and after the 2013 budget measures implementation. Detour Gold met the requirement for commercial production for income tax purposes during September 2013. Any asset additions or development costs incurred after June 13, 2013 were treated as described above for assets acquired post commercial production, i.e. sustaining.

22-2

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Detour Lake Mine NI 43-101 Technical Report

Mining Tax The Ontario mining tax rate is 10%, prior to the consideration of any processing allowances. The taxable income basis for mining tax, prior to calculating the processing allowance, is similar to that for Federal and Ontario Provincial income tax purposes, except for costs deemed to be unrelated to the mine activity. Similar to income tax, the development pool balances are available to reduce mining taxes payable over the LOM, although the amounts are divided into slightly different categories, i.e. mining, processing assets and exploration and development expenditures. The processing allowance deduction is also available and is equivalent to the lesser of: 8% of the cumulative processing capital costs or 65% of taxable income applicable to mining tax. No losses can be created through the use of tax depreciation for mining tax purposes. Ontario also provides for two income exemptions: 1. For new non-remote mines, in which the first $10 million in income is exempt from tax for 3 years, and 2. $0.5 million for each year the mine is in operation. Detour Gold believes it will not be able to take advantage of exemption #1 above. Over the LOM, mining taxes have been estimated at $375 million. 22.1.3 Discount Rate The discount rate applied to the cash flow to arrive at a NPV for the Detour Lake mine is intended to represent the weighted average cost of capital ("WACC"). The Detour Lake mine was evaluated on an all-equity basis, so in this case WACC is equal to the cost of equity. Historically, the risk premium for equity has been estimated at close to 5%. Over the past 10 years, real risk-free interest rates have ranged from near zero to around 5%. The real return on Canadian long bonds since January 2000 has averaged close to 2.5%. Consequently, it was decided to apply discount rates of 5%, 7.5%, and 10% in the Base Case.

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Economic Analysis

22.1.4 Summary of Assumptions Principal technical assumptions utilized in the economic analysis are provided in Table 22-1: Table 22-1

Technical Assumptions Unit

Value

Waste Mined

000s tonnes

1,675,750

Total Ore Milled

000s tonnes

476,439

Ore Grade to Mill

g/t Au

1.02

Gold Content

000s oz

15,549

Processing Rate (Steady State)

Tpd

61,000

Gold Recovery (Avg.)

%

Gold Inventory (GIC and In-transit)

000s oz

22.5

Gold Sales

000s oz

14,037

Silver Sales

000s oz

1,404

Gold Payability (Refined)

%

99.9

Gold Refining Charges

$/oz

4.00

Sustaining Capital

millions

1,143

Deferred Stripping

millions

614

Closure Funding

millions

69.6

92.2

22.1.5 Mine Closure The estimated costs of mine closure and ongoing maintenance were modeled in the year they were expected to be incurred and resulted in a closure liability of $69.6 million (undiscounted). The Detour Lake mine anticipates posting letters of credit or other similar bonding instruments to secure its mine closure obligations until reclamation activities commence. Mine closure expenditures would then be funded from project cash flow or accumulated cash balances. 22.1.6 Base Case Cash Flow The cash flow projection takes as its basis the mine production plan. Gold production and revenues are derived using the assumptions given above. Operating cost and working capital requirements were calculated for each period. The timing of capital expenditure was based on construction and equipment replacement schedules. Based on the above production, operating and capital expenditure plans, royalty and tax computations were prepared, and the pre- and after-tax cash flows were then discounted to derive their NPV. At the Base Case discount rate, NPV 5% is $3.42 billion and $2.79 billion before and after tax, respectively.

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Detour Lake Mine NI 43-101 Technical Report

LOM total cash costs1 are $723/oz sold. LOM TCC and total capital costs1 are $848/oz sold. Table 22-2 shows the Project after tax cash flow projection. Table 22-2

Simplified Cash Flow on an Annual Basis (after tax)

Year

(000s)

2014

53,618

2015

145,145

2016

123,644

2017

269,670

2018

294,321

2019

139,382

2020

179,322

2021

255,640

2022

156,250

2023

198,955

2024

194,774

2025

214,006

2026

111,917

2027

188,765

2028

275,220

2029

206,420

2030

309,527

2031

290,567

2032

420,560

2033

421,907

2034

450,456

2035

185,121

Total

5,085,184

22.1.7 Sensitivity Analysis Taking the Base Case described above as a starting point, the sensitivity of the Detour Lake mine pre-tax NPV 5% to changes in gold price, exchange rate, capital and operating costs was tested. Table 22-3 represents the results of this analysis. It can be seen that, as is typical for most mining projects, the drivers of revenue have the greatest impact on project returns. The economics of the Detour Lake mine are almost as sensitive to changes in the exchange rate, since these directly affect Canadian Dollar receipts but have little impact on estimated operating costs or on the Canadian Dollar denominated portion of the capital cost.

1

Refer to the section on Non-IFRS Financial Performance Measures at end of section 1.

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Economic Analysis

The Detour Lake mine is shown to be only moderately sensitive to overall operating costs, and has little sensitivity to capital cost changes within the range tested. Table 22-3

Sensitivity Analysis

Discount Rate

0%

5%

7.5%

10%

Pre-tax NPV Cdn$ billions @ US$1,000

3.42

1.64

1.18

0.87

Pre-tax NPV Cdn$ billions @ US$1,100

4.96

2.53

1.89

1.44

Pre-tax NPV Cdn$ billions @ US$1,200

6.50

3.42

2.60

2.02

Pre-tax NPV Cdn$ billions @ US$1,300

8.04

4.32

3.31

2.60

Pre-tax NPV Cdn$ billions @ US$1,400

9.58

5.21

4.02

3.18

-10%

Base case

3.50

3.42

-10%

Base case

4.05

3.42

2.80

1.05

Base case

+1.15

2.99

3.42

3.97

Gold price (US$/oz)

Capital Costs Pre-tax NPV 5% (Cdn$ billions)

Operating Costs Pre-tax NPV 5% (Cdn$ billions)

Foreign Exchange Pre-tax NPV 5% (Cdn$ billions)

+10% 3.35

+10%

22.1.8 Optimization of the Detour Lake mine’s Economics The project’s economics could be further improved by a number suggestions/recommendations that have been described in sections 24, 25 and 26.

of

Using the current financial model as the base case, these potential improvements will be further evaluated in 2014 and beyond.

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Detour Lake Mine NI 43-101 Technical Report

23.0 Adjacent Properties The Lipton Claim Group (also referred to as the Atkinson Project) is located 16 kilometres south of the Property. The most recent work on the property was a drilling program of 1,207 metres completed in 2010 by Atocha Resources. Highlights from the program included 0.89 g/t Au over 15 metres, and 10.66 g/t Au over 0.5 metres. Adventure Gold Inc. has two properties adjacent to the eastern Property boundary in Québec. The Manthet property is located north of the SLDZ trend. The Massicotte property is located along the strike of the MDZ and the LDDZ. Exploration in 2013 focused on ground and airborne geophysical surveys.

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Detour Lake Mine NI 43-101 Technical Report

24.0 Other Relevant Data and Information 24.1 Operational Information This section mainly summarizes the grade control measures implemented in 2012, and the 2013 reconciliation results against the reserve model. Grade Control and Delineation Ore control at the Detour Lake operation is performed through RC drilling and sampling. Grade control drilling is currently being performed through an external contract. Drill patterns vary depending on the mineralized zones with main patterns of 20 x 10 metres and 10 x 10 metres in selective areas. Grade control holes are angled to better intercept and define the sub-vertical zones of mineralization. Three full benches are targeted, resulting in 42 metre long RC holes. This allows for better short range planning and to confirm old underground openings several benches prior to mining. Assay lengths are 1 metre and may be increased to 2 metres intervals once sufficient data demonstrate acceptable characterization of the variability. Approximately 130,000 metres of RC drilling were completed in 2013 and similar meterage is planned for 2014. Once this initial drilling is completed, 73,000 metres of drilling are planned for each subsequent year of production. RC chip samples are taken at the drill, using a cone splitter for better sample reduction. A sample size of 4 to 5 kg is targeted for each metre drilled, thus reducing variability of a smaller sample. QA/QC procedures in use are similar to the exploration programs described in section 11.5.2, although no metallic screen assays are performed for grade control. Assays received are included in an onsite database using Maxwell Datashed software, and also replicated by Thon Consulting. Once assays have passed QA/QC checks, a ‘Grade Control’ model is generated following industry standard geostatistics procedures. Mining shapes are designed by Detour Gold geologists through Datamine software. The mining shapes are designed while considering blast patterns, mining equipment, mining direction, and other factors. The procedure attempts to segregate areas of high-grade and medium-grade material while minimizing internal waste and dilution of ore zones. Dilution Control Several procedures and technologies are currently in place to ensure dilution is understood and controlled: Technologies include: 

High-precision GPS in drills, shovels, & trucks;



Dispatch system monitoring;



Blast movement monitoring (BMM); and



Centric system to capture the information and for reporting.

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24-1

Other Relevant Data and Information

Procedures include: 

Ore blocks are marked in the field, on maps, and are visible on Wenco on-board display;



Ore spotters on day and night shifts;



Tracking through Dispatch System;



Planning of blast patterns around ore polygons;



Planning mining direction & shovels allocation by size; and



Planning pit work around ore.

24.2 Operational Results Reconciliation (Reserves to Mill) 2013 was the first year in which the Detour Lake mine could validate the reserve model against production through mine to mill reconciliation. Throughout the year, reconciliation of tonnes and ounces yielded positive increases from the predicted mineral reserves. Mill to reserves reconciliation (once adjusted for stockpile changes) were in excess of 20% in tonnes and 10% in ounces for the year. Results for the second half of the year yielded 15% more in tonnes and 15% more in ounces. This tendency while positive for 2013 has not been considered in the LOM. These results are based on mining less than 3% of the Detour Lake deposit, which may not be indicative for the entire LOM but will obviously be followed closely. The reserve model responded well in the higher grade mineralized areas. In addition, a significant amount of predicted marginal grade material returned higher than expected values. This unexpected additional tonnage had the effect of diluting the overall declared ore mine (DOM) grade. While dilution control has improved steadily in 2013, the grade of diluting material was clearly lower (0.20 g/t) than expected (0.40 g/t). Consequently, it has been corrected downward for the LOM. The dilution control and reconciliation results through 2013 support the use of 4% dilution at a grade of 0.20 g/t Au throughout the LOM. Although, the level of 4% dilution has been met in 2013, it was not sustained on a continuous basis. Consequently, a more conservative plan of 7% at 0.20 g/t Au has been used for 2014 as the company continues opening the pit and stabilizes its mining operations. 2013 Results vs. Forecast The initial forecast for 2013 predicted a head grade of 0.84 g/t Au, whereas the mill recorded a gold grade of 0.75 g/t Au. Key components that impacted grade are listed below (refer to Figure 24-1).

24-2

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Detour Lake Mine NI 43-101 Technical Report

Figure 24-1 2013 Reconciliation

1) Mined Tonnage and Mine Planning (approximately 0.05 g/t Au) The 2013 mine plan estimated a total of 69 Mt mined whereas the operation achieved 60 Mt. The shortage was mainly a function of low shovel productivity in overburden and low shovel availability. The shortfall of 9 Mt included approximately 2 Mt at a grade of 0.9 g/t Au, which had to be replaced in the plant feed by material from lower grade zones. 2) Mine Dilution (approximately 0.02 g/t Au) The 2013 mine plan included 5.6% dilution at 0.40 g/t. The overall dilution for the year was estimated at 13%. Although the trend improved towards the end of the year, the core of the dilution encountered in the first three quarters was mainly attributed to the following factors: 

Mining along strike caused by access constraints;



Inefficient shovel allocation;



Inefficient design and mining of small fringe zones resulting in excessive dilution;



Uneven ground caused by pit pioneering; and



Dilution with overburden material. Detour Gold decided to apply 7% for 2014 until it can demonstrate that the lower dilution results can be sustained. The company expects that for the start of 2015, the operation will be using the level of 4% assumed in the feasibility study and the LOM.

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Other Relevant Data and Information

3) December Plant Shut-Down and Stockpile (approximately 0.02 g/t Au) The higher grade zone (Domain 2) was exposed late in the year due to mining sequence and the amount of till that had to be removed. A significant portion of the material from the higher grade zones mined late in the year was not processed as planned and had to be stockpiled due to the plant shut-down in December. This stockpiled material is of higher grade than the material processed in the year.

24.3 Optimization Information The section covers some of the opportunities and plans to improve the gold production over the next coming years. Some of these initiatives have been included in the LOM plan as they were supported in the feasibility study (such as the plant debottlenecking) and others are opportunities that have arisen during the first year of operation. Elevated Cut-off Grade Strategy In the event that more ore were to continue being delineated by grade control, the added tonnes would offer an opportunity to apply an elevated CoG strategy. The stockpiling the lower grade material (and thereby processing higher grade ore in the plant) warrants some attention in 2014 and beyond. Additionally, given the digging and haulage capacities available (section 16), additional mining capacity would also serve to expose more ore than currently planned in a given period. This would further augment the opportunity to process better grade material while stockpiling all economic material for later processing. Mineralized Waste Detour Gold is currently segregating and stockpiling all mineralized waste being removed from the pit. This material is considered waste and is not part of the reserve. It is projected that at the end of the LOM, 107.3 Mt of material averaging approximately 0.45 g/t will be stockpiled. Detour Gold plans to continue segregating this material to potentially process it in a stronger gold price environment. Now that the operation has been established, Detour Gold will focus on stabilizing its operation. Shortly after and possibly in parallel, the company will also evaluate the amenability of the mineralized waste to other forms of treatment typically used for lower grade material and will also contemplate other methods including gold concentration by the natural segregation of fines. Process Plant Debottlenecking The company plans to continue its efforts to debottleneck the process plant. In 2013, daily production rates have already been tested to levels above the ultimate design of 61,000 tpd (up to 63,700 tpd). Hourly rates have also been tested to levels above 3,000 tpoh (both lines) while a single line has been tested as high as 1,600 tpoh. 24-4

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Detour Lake Mine NI 43-101 Technical Report

Globally, these results provide the confidence needed to support the debottlenecking required to sustain the higher production levels planned in the LOM. While the effect of the debottlenecking and optimization has been estimated to begin in 2016, the investment will begin in 2014. Please refer to section 17.4 for more details on the scope and section 21 on the cost. Process Plant Recovery On the recovery side, the LOM plan includes a recovery that is 1% above the feasibility study model. This change was supported with the 2013 recovery results where for three consecutive months recovery was 1.5% above the feasibility study, with a period of one month where recovery was 3% higher. Higher recoveries were also noted (up to 4% above the model) when the circuit was stable and the gravity circuit had high availability rates. While impressive, these recovery levels are not totally unexpected as it is common to have a process plant outperform the laboratory test work results. As the plant becomes more stable, it has the advantage (over the laboratory tests) to over-grind the heavier material such as gold and sulphides. As more operating data becomes available, the recovery model will be updated and refined to better predict the ultimate recovery potential. To this end, several optimization parameters have yet to be completed including: 1. Reduction of liquid losses; 2. Reduction of carbon losses; 3. Increase in gravity recovery and operating time; and 4. Oxygen and cyanide addition control.

24.4 Advanced Projects Block A The first phase of Detour Gold’s effort on Block A (immediately west of the Detour Lake mine) was to confirm the resource base. The Measured and Indicated mineral resources are estimated at 53.9 Mt grading 1.15 g/t Au for a total of 1.99 million ounces. It is expected that the Block A mineralized material will be amenable to the same type of process treatment as the Detour Lake ore. The logical next phase of work is to evaluate if an early development of this mineral resource would result in a better gold production profile for Detour Gold via an elevated CoG strategy or simply by mining the higher grade first. At this point, it is not expected that the Block A deposit could justify an expansion on its own but the potential to develop concurrently with the Detour Lake mine to improve the production profile without a significant injection of capital should be evaluated in the nearterm.

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24-5

Other Relevant Data and Information

The additional engineering work would contemplate the timing of development of the Block A deposit to take advantage of in-pit dumping, tailing deposition and/or comingling. These possibilities would most certainly reduce the overall costs for tailing management facilities. Following this evaluation phase and prior to concluding one way or the other, additional drilling would be required to test the continuity between the two deposits and potential extension of the M Zone to the west. Further effort should go into bringing the Block A project up to the level of a pre-feasibility study. Main areas for additional work include: 

Investigation into possible assay bias in some Trade Winds drill holes;



Further geochemical characterization of waste and mineralized material;



Improved estimates of mining dilution, costs and mining plans;



Added detail for waste and stockpile management and storage; and



Verification of operating cost, capital cost and subsequent economic analysis.

The status of work on Block A in relation to the requirements of a pre-feasibility study is summarized in Table 24-1: Table 24-1

Block A Pre-Feasibility Study Requirements

Subject Area

Pre-Feasibility Study

Location, Access, Climate, Infrastructure

Currently meets criteria

History, Geological Setting etc.

Currently meets criteria

Exploration, Drilling

Currently meets criteria

Sample Preparation

Currently meets criteria

Data Verification

Additional work required

Mineral Processing & Metallurgical Testing

Currently meets criteria

Mining: Grade Data

Currently meets criteria

Mining: Pit Slopes

Currently meets criteria

Mining: Dilution, Mine Plans, Costs

Additional work required

Recovery (including Tailings)

Currently meets criteria

Infrastructure

Currently meets criteria

Environmental, Permitting, Consultation

Additional work required

Capital & Operating Cost

Additional work required

Economic Analysis

Additional work required

It has been estimated that the cost to complete the pre-feasibility study on Block A would be in the order of $2 million.

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Detour Lake Mine NI 43-101 Technical Report

24.5 Exploration Organic Growth Opportunities Since the acquisition of the Property in 2007, the Company’s exploration activities have focused on delineating the Detour Lake and Block A deposits. Limited exploration work has been completed on the Company’s large prospective land position of 630 square kilometres. Lower Detour Area The Company’s near-term exploration strategy is to find and develop a high-grade gold deposit to take advantage of the nearby existing processing facility. To this end, in the last two years, the Company shifted its focus to regional exploration programs targeting various prospective areas along several important structures associated with the LDDZ, a major east-west regional shear zone extending for over 30 kilometres on the Property. In the 2013 winter drilling program, the Company defined three sub-parallel shear zones within 1 kilometre south of the LDDZ and 8 kilometres south of the Detour Lake mine. Anomalous to high-grade gold intercepts were encountered in all three zones (from south to north, Zones 58, 75 and 58N) over a distance of 3 kilometres. In Zone 75, two drill holes on the same section intersected 17.33 g/t over 4.4 metres and 6.19 g/t over 2.1 metres (core length), respectively. The gold mineralization is mainly associated with quartz veins (up to 1 metre wide) that are parallel to the shear zone. Early indications suggest that the metallurgy would be amenable to the existing process plant. The 2014 exploration program currently underway will test the potential extension of this high-grade mineralization and other prospective targets in the Lower Detour area. A large extent of the land package had limited exploration activity. Regional geophysical and geochemical surveys have been completed throughout the Property and prospective zones have been identified and remain to be tested through follow up work. QK Zone The QK Zone underground target (drilled by Placer Dome in the mid-1990s) requires further definition drilling to fully evaluate the potential of supplementing the mill with higher grade feed.

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Detour Lake Mine NI 43-101 Technical Report

25.0 Interpretation and Conclusions 25.1 Introduction The QPs, as authors of this Technical Report, have reviewed the data for the Property and are of the opinion that: 

Permits and mining tenure held by Detour Gold for the Property are in good standing;



Detour Gold is in compliance with the requirements for closure provisions; and



Detour Gold is operating according to industry standards. To the extent known, there are no significant factors or risks that may affect access, titles, or the right or ability to perform work on the Property.

25.2 Geology 

The Detour Lake area occurs as Orogenic greenstone-hosted hydrothermal lode gold deposit, like various other deposits in the region;



Majority of mineralization is associated with quartz veins generally striking 270° to 285° with sub-vertical dips to the north and lesser to the south. Detour Lake and Block A have been drilled, in the vast majority, by south dipping holes; and



The geology, mineralization style and setting at Detour Lake mine and Block A project are well understood and can support the estimation of mineral resources and reserves.

25.3 Drilling, Sampling, Data Verification 

SGS Geostat validated the core sampling procedures used by Detour Gold as part of an independent verification program;



SGS Geostat concluded that the drill core handling, logging and sampling protocols used by Detour Gold are at conventional industry standard and conform to generally-accepted best practices;



Through various external QA/QC audits, no evidence has been found of systematic gold contamination based on the blanks that were inserted with samples;



Rates of failure based on reference materials (standards) varied throughout various campaigns. Appropriate action was taken, including requests for repeat assays, for the QC failures;



Several independent analytical check programs on selected drill holes were carried out since 2006. The results of the duplicate samples generally show good to moderate correlation with the original assays, although a bias was seen for the Trade Winds drilling on the Block A project. Further testing showed that the impact on MRE was minimal and did not cause a material impact. Further investigation of Trade Winds duplicate grade discrepancy is recommended;

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25-1

Interpretation and Conclusions



The results of the check sampling programs outline the significant variability of the high gold values due to the nugget effect observed at the Detour Lake mine and Block A project, and highlight the necessity of capping the high gold values for the mineral resource estimation process; and



It is SGS Geostat’s opinion that Detour Gold is operating according to an industry standard QA/QC program for the insertion of control samples into the stream of samples for Detour Lake and Block A. The data is of quality sufficient to be used for mineral resource estimation.

25.4 Mineral Resource Estimate 

Detour Gold has been conducting drilling programs on the Detour Lake mine and Block A project since January 2007, the results of which have defined large gold mineralized systems. SGS Geostat completed mineral resource updates for the year-end 2013 based on 1,224,690 assays from 1,213,031 assayed metres;



Mineral resources are constrained by a Lerch-Grossman generated pit shell using a gold price of US$1,200/oz. All mineral resources are stated exclusive of mineral reserves and do not include any mining dilution allocation;



The total Detour Gold Measured and Indicated mineral resource is 136.3 Mt averaging 1.11 g/t Au for a total of 4.87 million ounces of gold. In addition, the Inferred mineral resource totals 21.7 Mt averaging 0.81 g/t Au for a total of 564,000 ounces of gold. The details are shown in Table 14-1; and



SGS Geostat believes that the assumptions, parameters, and interpretation are reasonable and appropriate for both deposits. Moreover, SGS Geostat finds the model and estimate acceptable and supports the current MREs.

25.5 Mineral Reserves and Mine Operations

25-2



The mineral reserve estimate is based on the 3D block model provided by SGS Geostat;



The pit optimization, using the LG 3D algorithm was based on an elevated CoG of 0.50 g/t Au;



The updated engineered pit design, using an optimized pit shell and the 2012 detailed mine design as a guide, includes the haulage road, required pit slopes, smoothed pit walls, proper bench configurations and geotechnical berms;



The mineral reserves, contained by the engineered pit design, were calculated using an elevated CoG 0.50 g/t Au at a gold price US$1,000/oz; and



The Proven and Probable reserves, including stockpiles of 2.4 Mt at a grade of 0.82 g/t Au as of December 31, 2013 amount to a total 476.4 Mt at 1.02 g/t Au, or 15.5 million ounces of contained gold.

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Detour Lake Mine NI 43-101 Technical Report

25.6 Mine Plan 

Total gold production after gold recovery factor is 14.3 million ounces over a period of 21.7 years;



The average gold production for the LOM is approximately 660,000 oz per year;



Total waste, including Inferred resources, backfilled stopes, overburden and waste rock is 1.68 billion tonnes, resulting in a strip ratio of 3.54 to 1;



The mining is being carried out by conventional open-pit mining methods using a fleet of drills, trucks and shovels operation method on the basis of two twelvehour shifts per day, seven days per week and 365 days per year;



Production forecasts are achievable with current equipment and the fleet expansions as described in section 16;



About 8 Mt of ore will be stockpiled by the end of 2016, securing approximately five months of production; and



This stockpile is dynamic and is being processed preferentially when material being mined from the pit is of lower grade.

25.7 Metallurgical Test Work 

It is BBA’s opinion that the metallurgical test work, plant design work and process operating cost estimates in this Technical Report are appropriate for the process operations at the Detour Lake mine. This opinion is based on Detour Gold’s operating experience in 2013, the test work completed for the feasibility study (BBA, 2010), the consistency of test work results throughout the deposit and BBA’s experience with similar deposits and process plants; and



The Block A metallurgical test work program showed that the grinding, crushing, gravity gold recovery and cyanide leach characteristics are very similar to the Detour Lake mine samples. Block A mineralized material can thus be milled in the process plant with the same throughput and recoveries. The Detour Lake mine recovery models can be used to represent the performance of the Block A mineralized material

25.8 Plant Operations and Tailing Management 

Review of the process plant data from October to December 2013 indicated that the gold recovery was 1 to 3% higher than predicted by the pre-feasibility study and feasibility study recovery model. Based on this data, a 1% gold recovery increase was added to the gold recovery model for the LOM plan; and



During 2013, Detour Gold obtained approval to amend the TMA design construction from ‘downstream’ to ‘centerline’. This results in decoupling the TMA construction requirements from material movements in the mine plan. Accordingly, the geochemically stable NAG waste required for TMA construction can be deferred and or reduced.

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25-3

Interpretation and Conclusions



During 2013, Detour Gold determined a management strategy for up to 650 Mt of tailings. This exceeds Detour Gold’s current reserves; and



Detour Gold identified and plans to implement a hybrid construction program consisting of self-performed earthwork together with selected contractor work as appropriate.

25.9 Sustaining and Operating Costs 

BBA has reviewed the estimates for operating costs and sustaining capital expenditures and is of the view that these estimates are reasonable and appropriate;



LOM average total cash costs are estimated to be $723/oz sold1, total cash costs and total capital costs are $848/oz sold; and



LOM sustaining capital expenditures totals $1.14 billion. The major expenditures relate to the tailing facility, mining equipment purchases and replacement, and mill improvement.

25.10 Economic Analysis and Sensitivity 

At the Base Case discount rate, NPV 5% is $3.42 billion and $2.79 billion before and after tax, respectively;



The economics of the Detour Lake mine are sensitive to changes in the exchange rate, since these directly affect Canadian Dollar receipts but have little impact on estimated operating costs or on the Canadian Dollar denominated portion of the capital cost; and



Detour Lake mine is shown to be only moderately sensitive to overall capital costs, and has little sensitivity to operating cost changes within the range tested.

25.11 Conclusion

1

25-4



In BBA’s opinion, this LOM updated plan provides economic estimates which are realistic and achievable;



The operating costs were predicated on first principles and current prices for materials and services, combined with experience obtained from 2013 operations;



The estimates contained in this report confirm the economic viability of the Detour Lake mine and provide a basis upon which to increase throughput and further optimize the overall project economics. Detour Gold has started a number of these initiatives.

Refer to the section on Non-IFRS Financial Performance Measures at end of section 1. 4 February 2014

Detour Lake Mine NI 43-101 Technical Report

26.0 Recommendations Since the feasibility study of June 2010, a large amount of work was completed to bring the Detour Lake mine into operation. The Detour Lake mine declared commercial production on September 1, 2013. In continuation with the work completed to date, some aspects of the mine operation will need to be examined in more detail to further optimize the economics of Detour Lake. The following recommendations should be taken into account:

26.1 Mining Operations 

Evaluation of the use of 7.5 metre benches (versus 12 metre benches) in central areas of the pit to be mined with the three available CAT 6060 hydraulic excavators. This evaluation is expected to result in improved dilution control with limited impact on equipment productivity;



Evaluation of the use of 15 metre benches in mining areas projected as waste. This bench height would be a better match to the size of the CAT 7495 rope shovels. In waste areas, higher benches can be expected to offer increased productivity, resulting in lower costs with minimal impact on dilution;



Evaluation and implementation of emerging technology to reduce variability in ore feed. Such technology has been proven to reduce interruptions in process plants and includes real time scanning of mining faces to minimize and/or manage variability in particle size, mineralogy and ore chemistry;



Mine plan projects stockpiling approximately three months of ore as a risk management strategy; and



Continue to segregate ‘mineralized waste’ which could potentially be processed during or after the LOM depending on the gold price environment.

26.2 Gold Recovery 

Potential revisions to the gold recovery model following several more months of operation data, as actual results in late 2013 have shown plus 3% more gold recovery than projections. Further amelioration of the gravity circuit (i.e. utilization) is a key aspect to further improve gold recovery.

26.3 Mineral Reserves 

Continuation of grade control process and validation for short-range planning (3 to 6 months);



Investigating and implementing methods and technology to improve grade control and mining selectivity, including smaller bench height using smaller loading equipment;

4 February 2014

26-1

Recommendations



Validation of mine to mill data reconciliation, including mining dilution and ore loss predictions; and



Investigation of potential improvement for pit slopes.

26.4 Drilling, Sampling, and Data Verification 

Further monitoring to investigate a potential bias on Trade Winds assay results (higher gold values) on the Block A project. Validation work on the estimation of mineral resources did show a minimal impact overall but it may be more significant locally. Additional sampling on the Trade Winds pulps is recommended. At year-end 2013, 125 supplemental half-core were sent for analysis and Detour Gold is in the process of locating original pulps for further testing;



Consideration towards preparing a matrix-matched RM (reference material) at this stage of both projects and for production samples for QA/QC; and



In the pre-feasibility study of the Detour Lake mine (Met-Chem, 2009), Scott Wilson RPA made a number of recommendations as part of their data verification program. Detour Gold has carried out a number of those recommendations. Detour Gold elected to address other recommendations according to timing and impact on production.

26.5 Block A Project 

Advance the Block A project to pre-feasibility level and evaluate best approach to incorporate into Detour Lake mine plan.

26.6 Exploration

26-2



Continuation of exploration programs in the Lower Detour area to follow up on the high-grade intercepts encountered in several structural zones; and



Further delineation work in the area between Detour Lake mine and Block A to allow for better modeling and estimation of potential mineralization adjacent to the mine.

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

27.0 References AMEC 2010a. EA for Electricity Projects, for the Diesel Power Generation Required to Support the Construction Phase. AMEC 2010b, EA for Electricity Projects, for Construction of a 230 kilovolt Transmission Line. AMEC 2010c, EA for Resource Stewardship and Facility Development Projects, for the Construction of Facilities Off-Lease. Barclay, W., 1993, Aspect of Structural Geology at the Detour Lake Mine, Ongoing Studies for Placer Dome Inc. BBA, 2010, Feasibility Study Report of the Detour Lake Project, Ontario for Detour Gold Corporation. September 2010. BBA, 2010, Technical Report Feasibility Study of the Detour Lake Project, Ontario for Detour Gold Corporation. June 30, 2010. BBA, 2012, Updated Mine Production Plan, NI 43-101 Technical Report of the Detour Lake Project, Ontario for Detour Gold Corporation. October 2012. Bernier, L., 2011, Petrographical and Lithogeochemical Analyses of an Amphibolite Unit (AM) from the Detour Mine Sequence, Detour Gold, Internal report prepared for Detour Gold Corp. Bloom, L., 2010, Review of the Detour Lake Project (Ontario) October 2009 – January 2010 Assay Quality Control Program, Internal report prepared by Analytical Solutions Ltd. for Detour Gold Corporation. February 2010. Refer to Appendix B. Bloom, L ., January-December 2012, Review of the Detour Lake Project (Ontario) Assay Quality Control Program for Block A Area for Detour Gold Corporation. March 17, 2013. Cyanco. SO2/Air Cyanide Destruction – Design Engineering Review. August 27, 2009. Geostat, 2008a, “Capping of gold values. Detour Lake Project. Second part : capping on original samples”, Memo of Robert de l’Etoile to Patrice Live dated April 22, 2008, 49p. Geostat, 2008b, “Variography of the Detour Gold project”. Memo of Robert de l’Etoile to Patrice Live dated May 16, 2008, 6p. Geostat, 2008c, “Capping of gold values, Detour Gold project”. Memo of Michel Dagbert to Patrice Live dated September 23, 2008, 14p. Geostat, 2009a, “Statistical and geostatistical analysis of gold grade sample data from the Detour Lake gold deposit”, dated April 02,2009, 29p. Golder Associates, 2006, Technical Report Mineral Resource Estimate: Detour Lake Property M Zone Gold Deposit Block A Porcupine Mining Division Province of Ontario for Trade Winds Ventures Inc. December 7, 2006. Golder Associates, 2011, Updates to the Pit Slope Design for the Detour Lake Project, Report 10-1117-0053. 4 February 2014

27-1

References

Kallio, Eric A., 2005, Technical Report for the Detour Lake Mine Option Property, Ontario for Pelangio Mines Inc. May 10, 2005. Kallio, Eric A., 2006, Technical Report for the Detour Lake Mine Option Property, Ontario for Detour Gold Corporation. September 21, 2006. Kessin, P., Gold Ore Processing Summary for the Detour Lake Mine. August 28, 2007. Knelson Research & Technology Centre, Gravity Modelling Report, Project No. KRTS 2021-8. March 3, 2010. Marmont, S. and Corfu, F. 1989, Timining of gold mineralization in the late Archean tectonic framework of the Canadian Shield; evidence from U-Pb zircon geochronology of the Abitibi sub-province, in the The Geology of Gold Deposits; the perspective in 1988, (ed) R.R. Keays, W.R.H. Ramsey and D.I. Groves; Economic Geology, Monograph 6, p. 101-111. Melis Engineering Ltd. Memorandum, Detour Gold Project - Metallurgical Composite Selection and Preparation – Rev. 3. June 24, 2008. Met-Chem Canada Inc., Technical Report Pre-feasibility of the Detour Lake Project, Ontario, for Detour Gold Corporation. October 19, 2009. Oliver, J. et al., 2012, Structure, Stratigraphy, U-Pb Geochronology and Alteration Characteristics of Gold Mineralization at the Detour Lake Gold Deposit, Ontario, Canada, Canadian Institute of Mining: Exploration and Mining Geology, Vol. 20, p.1-30. Ontario Geological Survey, 2009, Ontario airborne geophysical surveys, magnetic data, grid and profile data (ASCII and Geosoft® formats) and vector data, Detour Lake area; Ontario Geological Survey, Geophysical Data Set 1062. Pressacco, R., 1999, Economic Geology and Mineralization at the Detour Lake Mine, Ontario Geological Survey Open File Report 5985, p. 52-76. Starkey, J., Detour Lake Report – Mill sizing. October, 2009. Watts, Griffis and McOuat Limited, 2007, Updated National Instrument 43-101 Compliant Mineral Resource Estimate for the Detour Lake Project, Ontario for Detour Gold Corporation. December 11, 2007. Watts, Griffis and McOuat Limited, 2008, Technical Report and Mineral Resource Estimate for the Detour Lake Mine Option Property, Ontario for Detour Gold Corporation. January 25, 2008. Watts, Griffis and McOuat Limited, 2008, Technical Report and Mineral Resource Estimate Update for the Detour Lake Mine Option Property, Ontario, for Detour Gold Corporation. August 18, 2008. Watts, Griffis and McOuat Limited, 2009, Technical Report and Mineral Resource Estimate on the Block A Property, Ontario, Canada for Trade Winds Ventures Inc. July 9, 2009.

27-2

4 February 2014

Detour Lake Mine NI 43-101 Technical Report

Watts, Griffis and McOuat Limited, 2011, Technical Report and Mineral Resource Update on the Block A Property, Ontario, Canada for Trade Winds Ventures Inc. February 14, 2011.

4 February 2014

27-3

Detour Lake Mine NI 43-101 Technical Report

28.0 QP Certificates

4 February 2014

28-1

630, René-Lévesque Blvd. West Suite 2500 Montréal (Québec) H3B 1S6 CANADA T +1 514.866.2111 F +1 514.866.2116

CERTIFICATE OF AUTHOR To Accompany the Technical Report entitled:

“Detour Lake Mine – NI 43-101 Technical Report” for Detour Gold Corporation dated February 4, 2014 I, André Allaire, Eng., residing at 1826 chemin du Fief, St-Lazare, P.Q., J7T 2N5, do hereby certify that:

1) I am Acting President and CEO of BBA with an office at 630, René-Lévesque West, Suite 2500, Montréal, Québec, H3A 1S6; 2) I graduated from McGill University of Montréal with a B. Eng. in Metallurgy in 1982, a M. Eng. in 1986 and a Ph.D. in 1991. I am in good standing as a member of the Order of Engineers of Québec (#38480) and a member of the Canadian Institute of Mining Metallurgy and Petroleum. I have practiced my profession continuously since my graduation. My relevant experience for the purpose of the Technical Report is: • • • • • •

(1982-1984); Process Metallurgist, Horne division, Noranda Inc. (1984-1988); Graduate Studies, Metallurgical Department, McGill University (1988-2000); Process Metallurgist and Study Manager, Hatch & Associés Inc. (2000-2004); Manager Process and Metallurgy, Met-Chem Canada Inc. (2004-2011); Director, Mining and Metals, BBA Inc. (2011-to date);VP Market, Mining and Metals, BBA Inc.

3) I have read the definition of “qualified person” set out in National Instrument 43-101 (“NI 43-101”) and certify that, by reason of my education, affiliation with a professional association and past relevant work experience, I fulfill the requirements to be an independent qualified person for the purposes of NI 43-101; 4) I am responsible for the coordination of the complete Technical Report and for the preparation of sections 1 to 6, 13 and 17 to 27 (excluding 17.4) of the Technical Report; 5) I have had prior involvement with the property that is the subject of the Technical Report. In 2012, I was a co-author of the technical report entitled “Detour Lake Updated Mine Production Plan” dated October 18, 2012 and in 2011, I was a co-author of the “Technical Report - Mineral Resource and Mineral Reserve Update for the Detour Lake Project, Ontario” dated March 15, 2011, in 2010, I was the co-author of the “Technical Report – Feasibility Study of the Detour Lake Project, Ontario for Detour Gold Corporation” dated June 30, 2010, and in 2009, I was a co-author of the, "Technical Report – Pre-Feasibility of the Detour Lake Project, Ontario for Detour Gold Corporation" dated October 19, 2009; 6) I have visited the site on March 25, 2010 and several times during this period between July to November, 2013. 7) I have no personal knowledge as of the date of this certificate of any material fact or change, which is not reflected in this report;

630, René-Lévesque Blvd. West Suite 2500 Montréal (Québec) H3B 1S6 CANADA T +1 514.866.2111 F +1 514.866.2116

8) Neither I, nor any affiliated entity of mine, is at present under an agreement, arrangement or understanding or expects to become an insider, associate, affiliated entity or employee of Detour Gold Corporation, or any associated or affiliated entities; 9) Neither I, nor any affiliated entity of mine, own directly or indirectly nor expect to receive, any interest in the properties or securities of Detour Gold Corporation or any associated or affiliated companies; 10) Neither I, nor any affiliated entity of mine, have earned the majority or our income during the preceding three years from Detour Gold Corporation or any associated or affiliated companies; 11) I have read NI 43-101 and Form 43-101F1 and have prepared the technical report in compliance with NI 43-101 and Form 43-101F1, and have prepared the report in conformity with the generally accepted Canadian Mining Industry practice and, as of the effective date of the Technical Report , to the best of my knowledge, information and belief, the technical report contains all scientific and technical information that is required to be disclosed to make the technical report not misleading.

Dated this 4th day of February, 2014.

(Signed and Sealed) “André Allaire” ______________________________ André Allaire, Eng., M. Eng., PhD. Acting President and CEO BBA Inc.

630, René-Lévesque Blvd. West Suite 2500 Montréal (Québec) H3B 1S6 CANADA T +1 514.866.2111 F +1 514.866.2116

CERTIFICATE OF AUTHOR To Accompany the Technical Report entitled:

“Detour Lake Mine – NI 43-101 Technical Report” for Detour Gold Corporation dated February 4, 2014 I, Patrice Live, Eng., do hereby certify that: 1) I am Director, Mining with BBA with an office at 630, René-Lévesque West, Suite 2500, Montréal, Québec, H3A 1S6; 2) I graduated from Laval University in 1976; 3) I am a registered member of the Order of Engineers of Québec (#38991); 4) I have worked as a mining engineer continuously since my graduation from university; 5) I have read the definition of “qualified person” set out in National Instrument, 43-101 (“NI 43-101”) and certify that, by reason of my education, affiliation with a professional association and past relevant work experience, I fulfill the requirements to be an independent qualified person for the purposes of NI 43-101; 6) I am responsible for the preparation of sections 15 and 16 of the Technical Report; 7) I have had prior involvement with the property that is the subject of the Technical Report. In 2012, I was a co-author of the technical report entitled “Detour Lake Updated Mine Production Plan” dated October 18, 2012, in 2011, I was a co-author of the “Technical Report - Mineral Resource and Mineral Reserve Update for the Detour Lake Project, Ontario” dated March 15, 2011, in 2010, I was the co-author of the “Technical Report – Feasibility Study of the Detour Lake Project, Ontario for Detour Gold Corporation” dated June 30, 2010, in 2009, I was a co-author of the "Technical Report – Pre-Feasibility of the Detour Lake Project, Ontario for Detour Gold Corporation" dated October 19, 2009, and in 2008, I was co-author of the "Technical Report and Mineral Resource Estimate Update for the Detour Lake Mine Option Property, Ontario for Detour Gold Corporation" dated August 18, 2008; 8) I have visited the site on January 4 and 5, 2012; 9) I have no personal knowledge as of the date of this certificate of any material fact or change, which is not reflected in this report; 10) Neither I, nor any affiliated entity of mine, is at present under an agreement, arrangement or understanding or expects to become an insider, associate, affiliated entity or employee of Detour Gold Corporation, or any associated or affiliated entities; 11) Neither I, nor any affiliated entity of mine, own directly or indirectly nor expect to receive, any interest in the properties or securities of Detour Gold Corporation or any associated or affiliated companies;

Page 2

12) Neither I, nor any affiliated entity of mine, have earned the majority or our income during the preceding three years from Detour Gold Corporation or any associated or affiliated companies; 13) I have read NI 43-101 and Form 43-101F1 and have prepared the technical report in compliance with NI 43-101 and Form 43-101F1; and have prepared the report in conformity with the generally accepted Canadian Mining Industry practice and, as of the effective date of the Technical Report, to the best of my knowledge, information and belief, the technical report contains all scientific and technical information that is required to be disclosed to make the technical report not misleading.

Dated this 4th day of February, 2014.

(Signed and Sealed) “Patrice Live” Patrice Live, Eng. Director, Mining BBA Inc.

CERTIFICATE OF AUTHOR Maxime Dupéré To Accompany the Report entitled: “Detour Lake Mine – NI 43-101 Technical Report” for Detour Gold Corporation dated February 4, 2014

I, Maxime Dupéré, P.Geo., do hereby certify that: 1)

I am senior geologist with SGS Canada Inc. - Geostat with an office at 10 Blvd Seigneurie East, Suite 203, Blainville, Quebec, Canada, J7C 3V5;

2)

I am a graduate of the Université de Montréal, Quebec in 1999 with a B.Sc. in geology and I have practiced my profession continuously since 2001.

3)

I am a registered member of the Ordre des Géologues du Québec (#501).

4)

My relevant experience includes 12 years’ experience in mining exploration in diamonds, gold, silver, base metals, and Iron Ore. My experience also includes 6 years of consulting in mineral resource estimations for different exploration projects at different stages of exploration.

5)

I have read the definition of “qualified person” set out in National Instrument 43-101 (“NI 43-101”) and certify that by reason of my education, affiliation with a professional association and past relevant work experience, I fulfil the requirements to be an independent qualified person for the purposes of NI 43-101;

6)

I have participated in the preparation of sections 7 to 12 of this technical report;

7)

I have had prior involvement with the property that is the subject of the Technical Report. In 2012, I was a co-author of the technical report entitled “Detour Lake Updated Mine Production Plan” dated October 18, 2012;

8)

I have visited the site between November 1st to November 4th, 2011 and between July 23rd to July 26th 2013;

9)

I have no personal knowledge as of the date of this certificate of any material fact or change, which is not reflected in this report;

10)

Neither I, nor any affiliated entity of mine, is at present, under an agreement, arrangement or understanding or expects to become, an insider, associate, affiliated entity or employee of Detour Gold Corporation, or any associated or affiliated entities;

Geostat SGS Canada Inc.

10 boul. de la Seigneurie Est, Suite 203, Blainville, Québec Canada J7C 3V5 t (450) 433-1050 f (450) 433-1048 www.geostat.com www.met.sgs.com Membre du Groupe SGS (SGS SA)

11)

Neither I, nor any affiliated entity of mine, own, directly or indirectly, nor expect to receive, any interest in the properties or securities of Detour Gold Corporation, or any associated or affiliated companies;

12)

Neither I, nor any affiliated entity of mine, have earned the majority of our income during the preceding three years from Detour Gold Corporation, or any associated or affiliated companies;

13)

I have read NI 43-101 and Form 43-101F1 and have prepared the technical report in compliance with NI 43-101 and Form 43-101F1, and have prepared the report in conformity with generally accepted Canadian mining industry practice, and as of the effective date of the technical report, to the best of my knowledge, information and belief, the technical report contains all scientific and technical information that is required to be disclosed to make the technical report not misleading.

Dated this 4th day of February, 2014. (Signed and Sealed) “Maxime Dupéré” _______________________________ Maxime Dupéré, P.Geo, Senior Geologist SGS Canada Inc. - Geostat

Geostat SGS Canada Inc.

10 boul. de la Seigneurie Est, Suite 203, Blainville, Québec Canada J7C 3V5 t (450) 433-1050 f (450) 433-1048 www.geostat.com www.met.sgs.com Membre du Groupe SGS (SGS SA)

CERTIFICATE OF AUTHOR Yann Camus

To Accompany the Technical Report entitled: “Detour Lake Mine – NI 43-101 Technical Report” for Detour Gold Corporation dated February 4, 2014

I, Yann Camus, Eng., do hereby certify that: 1)

I am project engineer with SGS Canada Inc. - Geostat with an office at 10 Blvd de la Seigneurie East, Suite 203, Blainville, Quebec, Canada, J7C 3V5;

2)

I am a graduate from École Polytechnique de Montréal in 2000.

3)

I am an engineer and a registered member of the Ordre des Ingénieurs du Quebec (#125443);

4)

I have worked as a geological engineer continuously since my graduation from university. My technical expertise includes resources evaluation. I have been involved in several resource, prefeasibility and feasibility studies as well as preliminary economic assessments. I have participated in worldwide projects in precious and base metals, rare earths, iron, bauxite and industrial minerals, including hard rock, detritic and oxidized environments;

5)

I have read the definition of “qualified person” set out in National Instrument 43-101 (“NI 43-101”) and certify that by reason of my education, affiliation with a professional association and past relevant work experience, I fulfil the requirements to be an independent qualified person for the purposes of NI 43-101;

6)

I have participated in the preparation of section 14 of this Technical Report;

7)

I have had no prior involvement with the property that is the subject of the Technical Report;

8)

I have not visited the site;

9)

I have no personal knowledge as of the date of this certificate of any material fact or change, which is not reflected in this report;

10)

Neither I, nor any affiliated entity of mine, is at present, under an agreement, arrangement or understanding or expects to become, an insider, associate, affiliated entity or employee of Detour Gold Corporation, or any associated or affiliated entities;

Geostat SGS Canada Inc.

10 boul. de la Seigneurie Est, Suite 203, Blainville, Québec Canada J7C 3V5 t (450) 433-1050 f (450) 433-1048 www.geostat.com www.met.sgs.com Membre du Groupe SGS (SGS SA)

11)

Neither I, nor any affiliated entity of mine, own, directly or indirectly, nor expect to receive, any interest in the properties or securities of Detour Gold Corporation, or any associated or affiliated companies;

12)

Neither I, nor any affiliated entity of mine, have earned the majority of our income during the preceding three years from Detour Gold Corporation, or any associated or affiliated companies;

13)

I have read NI 43-101 and Form 43-101F1 and have prepared the technical report in compliance with NI 43-101 and Form 43-101F1, and have prepared the report in conformity with generally accepted Canadian mining industry practice, and as of the effective date of the technical report, to the best of my knowledge, information and belief, the technical report contains all scientific and technical information that is required to be disclosed to make the technical report not misleading.

Dated this 4th day of February, 2014. (Signed and Sealed) “Yann Camus” _______________________________ Yann Camus, Eng., Project Engineer SGS Canada Inc. - Geostat

Geostat SGS Canada Inc.

10 boul. de la Seigneurie Est, Suite 203, Blainville, Québec Canada J7C 3V5 t (450) 433-1050 f (450) 433-1048 www.geostat.com www.met.sgs.com Membre du Groupe SGS (SGS SA)

CERTIFICATE OF AUTHOR

To Accompany the Technical Report entitled: “Detour Lake Mine – NI 43-101 Technical Report” for Detour Gold Corporation dated February 4, 2014 I, David G. Ritchie, M.Eng., P.Eng , do hereby certify that: 1) I am a Senior Associate Geotechnical Engineer and Geotechnical Engineering Group

Manager in the consulting firm AMEC Environment & Infrastructure, a Division of AMEC Americas Limited, 160 Traders Blvd. East, Suite 110 Mississauga, ON Canada L4Z 3K7 2)

I graduated from Ryerson Polytechnic University in 1995 with a B.Eng. in Civil Engineering and in 2000 from the University of Western Ontario with a M.Eng.

3) I am Professional Engineer in the Province of Ontario (Reg. # 90488198); 4) I have practiced my profession for eighteen years since my graduation from university; I have read the definition of “qualified person” set out in National Instrument 43-101 (“NI 43-101”) and certify that, by reason of my education, affiliation with a professional association and past relevant work experience, I fulfill the requirements to be an independent qualified person for the purposes of NI 43-101; 5) I am responsible for supervising the preparation of section 17.4 of the Technical Report; 6) I have had prior involvement with the property that is the subject of the Technical Report. In 2012, I was a co-author of the technical report entitled “Detour Lake Updated Mine Production Plan” dated October 18, 2012 and in 2011 and 2012, I consented, on behalf of AMEC, to the use of the “Technical Report – Feasibility Study of the Detour Lake Project, Ontario for Detour Gold Corporation” dated June 30, 2010 in the short form prospectuses of Detour Gold Corporation dated July 27, 2011 and February 7, 2012; 7) I have visited the site on at least 4 occasions in each of 2011 and 2012; 8) I have no personal knowledge as of the date of this certificate of any material fact or change, which is not reflected in this report; 9) Neither I, nor any affiliated entity of mine, is at present under an agreement, arrangement or understanding or expects to become an insider, associate, affiliated entity or employee of Detour Gold Corporation, or any associated or affiliated entities; 10) Neither I, nor any affiliated entity of mine, own directly or indirectly nor expect to receive, any interest in the properties or securities of Detour Gold Corporation or any associated or affiliated companies; 11) Neither I, nor any affiliated entity of mine, have earned the majority or our income during the preceding three years from Detour Gold Corporation or any associated or affiliated companies; 12) I have read NI 43-101 and Form 43-101F1 and section 17.4 of the Technical Report has been prepared in compliance with NI 43-101 and Form 43-101F1 and in conformity with the generally accepted Canadian Mining Industry practice and, as of the effective date of the Technical Report, to

the best of my knowledge, information and belief, the technical report contains all scientific and technical information that is required to be disclosed to make the technical report not misleading.

Dated this 4th day of February, 2014.

(Signed and Sealed) “David G. Ritchie” ______________________________ David G. Ritchie, M.Eng., P.Eng Senior Associate Geotechnical Engineer AMEC Environment & Infrastructure, a Division of AMEC Americas Limited

Detour Lake Mine NI 43-101 Technical Report

Appendices Appendix A 

List of Claims / Claim Map .................................................. A-1 

Appendix B 

ASL Report (L. Bloom, March 17, 2013) ............................ B-1 

I

Detour Lake Mine NI 43-101 Technical Report

Appendix A

List of Claims / Claim Map

A-1

Detour Lake Mine NI 43-101 Technical Report

Detour Gold Corporation Land Holdings, Detour Lake Property (Ontario & Quebec) Land Tenure as of January 7, 2014

Claim #/Lease/Patent 1090117 1090118 1090119 1090120 1114018 1114019 1133200 1133201 1133202 1133203 1133204 1133205 1154536 1154537 1154538 1154539 1154540 1154541 1154542 1154543 1154544 1154545 1154546 1154547 1154548 1154550 1154725 1154726 1154727 1154728 1154729 1155035 1155036 1155038 1155039 1155040 1155041 1155042 1155043 1155045 1155046 1155047 1155048 1155049 1155050

Ownership Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation

Township/Area

Recorded Date

DueDate/Expiry

Area (Ha)

Work Credits Required

NSR/NPI

Lower Detour Lake

March 1, 1989

March 1, 2014

16.000

$400.00

7.5% NPI to Prism Resources Inc.

Lower Detour Lake

March 1, 1989

March 1, 2014

16.000

$400.00

7.5% NPI to Prism Resources Inc.

Lower Detour Lake

March 1, 1989

March 1, 2014

16.000

$400.00

7.5% NPI to Prism Resources Inc.

Lower Detour Lake

March 1, 1989

March 1, 2014

16.000

$400.00

7.5% NPI to Prism Resources Inc.

Lower Detour Lake

April 25, 1989

April 25, 2014

16.000

$400.00

7.5% NPI to Prism Resources Inc.

Lower Detour Lake

April 25, 1989

April 25, 2014

16.000

$400.00

7.5% NPI to Prism Resources Inc.

Hopper Lake

August 21, 1990

August 21, 2014

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

August 21, 1990

August 21, 2014

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

August 21, 1990

August 21, 2014

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

August 21, 1990

August 21, 2014

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

August 21, 1990

August 21, 2014

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

August 21, 1990

August 21, 2014

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

West of Sunday Lake West of Sunday Lake West of Sunday Lake

West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake Hopper Lake Hopper Lake

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

West of Sunday Lake

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

Sunday Lake

July 12, 1994

July 12, 2015

32.000

$800.00

2% NSR to Franco Nevada & 1% Goldcorp

Sunday Lake

July 12, 1994

July 12, 2015

192.000

$4,800.00

2% NSR to Franco Nevada & 1% Goldcorp

Sunday Lake

July 12, 1994

July 12, 2015

64.000

$1,600.00

2% NSR to Franco Nevada & 1% Goldcorp

Sunday Lake

July 12, 1994

July 12, 2014

256.000

$6,400.00

2% NSR to Franco Nevada & 1% Goldcorp

Sunday Lake

July 12, 1994

July 12, 2014

128.000

$3,200.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

West of Sunday Lake West of Sunday Lake

West of Sunday Lake West of Sunday Lake West of Sunday Lake Hopper Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake Hopper Lake

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp Appendix A-1

Detour Lake Mine NI 43-101 Technical Report

Claim #/Lease/Patent 1155051 1155052 1155053 1155054 1155055 1155056 1155057 1155058 1155059 1155060 1155061 1155062 1155063 1155064 1155065 1155066 1158819 1158820 1160145 1160146 1160147 1160148 1160149 1160150 1160151 1160200 1189624 1189626 1189627 1189628 1189629 1189630 1189631 1189904 1189905 1189906 1189908 1190901 1190902 1190903 1204525 1204526 1204527 1208318

1208321

1212940

Ownership Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Tradewinds & Detour Gold Corporation Tradewinds & Detour Gold Corporation Tradewinds & Detour Gold Corporation

Township/Area

Recorded Date

DueDate/Expiry

Area (Ha)

Work Credits Required

NSR/NPI

Hopper Lake

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake Hopper Lake Hopper Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

May 28, 1990

May 28, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 28, 1990

May 28, 2014

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

August 21, 1990

August 21, 2014

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

August 21, 1990

August 21, 2014

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

March 15, 1994

March 15, 2015

48.000

$1,200.00

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

March 15, 1994

March 15, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

March 15, 1994

March 15, 2015

32.000

$800.00

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

March 15, 1994

March 15, 2015

64.000

$1,600.00

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

March 15, 1994

March 15, 2015

64.000

$1,600.00

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

March 15, 1994

March 15, 2015

64.000

$1,600.00

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

March 15, 1994

March 15, 2015

64.000

$1,600.00

2% NSR to Franco Nevada & 1% Goldcorp

March 2, 1994

March 2, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

April 13, 1992

April 13, 2014

256.000

$6,400.00

2% NSR to Franco Nevada & 1% Goldcorp

April 13, 1992

April 13, 2014

32.000

$800.00

2% NSR to Franco Nevada & 1% Goldcorp

April 13, 1992

April 13, 2015

96.000

$2,400.00

2% NSR to Franco Nevada & 1% Goldcorp

April 13, 1992

April 13, 2015

192.000

$4,800.00

2% NSR to Franco Nevada & 1% Goldcorp

April 13, 1992

April 13, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

April 13, 1992

April 13, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

April 13, 1992

April 13, 2014

96.000

$2,400.00

2% NSR to Franco Nevada & 1% Goldcorp

April 13, 1992

April 13, 2014

192.000

$4,800.00

2% NSR to Franco Nevada & 1% Goldcorp

April 13, 1992

April 13, 2014

32.000

$800.00

2% NSR to Franco Nevada & 1% Goldcorp

April 13, 1992

April 13, 2014

32.000

$800.00

2% NSR to Franco Nevada & 1% Goldcorp

West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake Hopper Lake

April 13, 1992

April 13, 2014

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

September 18, 1992

September 18, 2015

96.000

$2,400.00

2% NSR to Franco Nevada & 1% Goldcorp

September 18, 1992

September 18, 2015

32.000

$800.00

2% NSR to Franco Nevada & 1% Goldcorp

September 18, 1992

September 18, 2015

16.000

$400.00

2% NSR to Franco Nevada & 1% Goldcorp

Lower Detour Lake

August 8, 1994

August 8, 2014

48.000

$1,200.00

7.5% NPI to Prism Resources Inc.

Lower Detour Lake

August 8, 1994

August 8, 2014

128.000

$3,200.00

7.5% NPI to Prism Resources Inc.

Lower Detour Lake

August 8, 1994

August 8, 2014

16.000

$400.00

7.5% NPI to Prism Resources Inc.

West of Sunday Lake

June 27, 1995

June 27, 2014

32.000

$800.00

West of Sunday Lake

June 27, 1995

June 27, 2014

96.000

$2,400.00

West of Sunday Lake

January 22, 1997

January 22, 2014

128.000

$3,200.00

West of Sunday Lake West of Sunday Lake West of Sunday Lake

2% NSR to Franco Nevada

2% NSR to Franco Nevada

2% NSR to Franco Nevada

Appendix A-2

Detour Lake Mine NI 43-101 Technical Report

Claim #/Lease/Patent 1212941 1218759 1241030 1241031 1241032 1241033 1244190 1244191 1244192 1244193 1244194 1244195 1244196 1244197 1244198 1244199 1244200 1248598 1248599 1248600 1249137 1249138 1249139 1249140 1249141 1249142 1249143 1249144 1249145 1249146 1249147 1249148 1249149 1249150 1249151 2329554 2329555 2329556 2329557 2329558 2329559 2329560 2329561 2329562 2329563 2329564 2329565 2329566

Ownership Tradewinds & Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation

Township/Area

Recorded Date

DueDate/Expiry

Area (Ha)

Work Credits Required

West of Sunday Lake

January 22, 1997

January 22, 2014

96.000

$2,400.00

West of Sunday Lake

August 8, 1996

August 8, 2014

192.000

$4,800.00

Hopper Lake

May 8, 2002

May 8, 2015

256.000

$6,400.00

Hopper Lake

May 8, 2002

May 8, 2015

256.000

$6,400.00

Hopper Lake

May 8, 2002

May 8, 2015

192.000

$4,800.00

Hopper Lake

NSR/NPI

2% NSR to Franco Nevada 2% NSR to Franco Nevada & 1% Goldcorp

May 8, 2002

May 8, 2015

256.000

$6,400.00

April 23, 2002

April 23, 2015

224.000

$5,600.00

2% NSR to D. Jones et al.

April 23, 2002

April 23, 2015

256.000

$6,400.00

2% NSR to D. Jones et al.

April 23, 2002

April 23, 2015

256.000

$6,400.00

2% NSR to D. Jones et al.

April 23, 2002

April 23, 2015

256.000

$6,400.00

2% NSR to D. Jones et al.

April 23, 2002

April 23, 2015

128.000

$3,200.00

2% NSR to D. Jones et al.

April 23, 2002

April 23, 2015

208.000

$5,200.00

2% NSR to D. Jones et al.

April 23, 2002

April 23, 2015

96.000

$2,400.00

2% NSR to D. Jones et al.

April 23, 2002

April 23, 2015

32.000

$800.00

2% NSR to D. Jones et al.

April 23, 2002

April 23, 2015

96.000

$2,400.00

2% NSR to D. Jones et al.

April 23, 2002

April 23, 2015

192.000

$4,800.00

2% NSR to D. Jones et al.

Lower Detour Lake

October 25, 2002

October 25, 2014

64.000

$1,600.00

Lower Detour Lake

October 25, 2002

October 25, 2014

64.000

$1,600.00

Lower Detour Lake

October 25, 2002

October 25, 2014

64.000

$1,600.00

Lower Detour Lake

October 25, 2002

October 25, 2014

48.000

$1,200.00

Lower Detour Lake

June 3, 2002

June 3, 2014

128.000

$3,200.00

2% NSR to Franco Nevada & 1% Goldcorp

Lower Detour Lake

June 3, 2002

June 3, 2014

240.000

$6,000.00

2% NSR to Franco Nevada & 1% Goldcorp

Lower Detour Lake

June 3, 2002

June 3, 2014

192.000

$4,800.00

2% NSR to Franco Nevada & 1% Goldcorp

Lower Detour Lake

June 3, 2002

June 3, 2014

224.000

$5,600.00

Lower Detour Lake

June 3, 2002

June 3, 2014

160.000

$4,000.00

2% NSR to Franco Nevada & 1% Goldcorp

Lower Detour Lake

June 3, 2002

June 3, 2014

224.000

$5,600.00

2% NSR to Franco Nevada & 1% Goldcorp

Lower Detour Lake

June 3, 2002

June 3, 2014

64.000

$1,600.00

Lower Detour Lake

June 3, 2002

June 3, 2014

224.000

$5,600.00

Lower Detour Lake

June 3, 2002

June 3, 2014

256.000

$6,400.00

Lower Detour Lake

June 3, 2002

June 3, 2014

256.000

$6,400.00

Lower Detour Lake

June 3, 2002

June 3, 2014

240.000

$6,000.00

Lower Detour Lake

June 3, 2002

June 3, 2014

256.000

$6,400.00

Lower Detour Lake

June 3, 2002

June 3, 2014

256.000

$6,400.00

Lower Detour Lake

June 3, 2002

June 3, 2014

64.000

$1,600.00

Lower Detour Lake

June 3, 2002

June 3, 2014

160.000

$4,000.00

2% NSR to Franco Nevada & 1% Goldcorp

Massicotte

February 6, 2012

August 28, 2015

55.440

$3,325.18

2% NSR to Franco Nevada & 1% Goldcorp

Massicotte

February 6, 2012

August 28, 2015

55.440

$3,325.18

2% NSR to Franco Nevada & 1% Goldcorp

Massicotte

February 6, 2012

August 28, 2015

7.300

$437.84

2% NSR to Franco Nevada & 1% Goldcorp

Massicotte

February 6, 2012

August 28, 2015

7.310

$438.44

2% NSR to Franco Nevada & 1% Goldcorp

Massicotte

February 6, 2012

August 28, 2015

41.060

$2,462.70

2% NSR to Franco Nevada & 1% Goldcorp

Massicotte

February 6, 2012

August 28, 2015

31.190

$1,870.72

2% NSR to Franco Nevada & 1% Goldcorp

Massicotte

February 6, 2012

August 28, 2015

3.730

$223.72

2% NSR to Franco Nevada & 1% Goldcorp

Massicotte

February 6, 2012

August 28, 2015

28.390

$1,702.78

2% NSR to Franco Nevada & 1% Goldcorp

Massicotte

February 6, 2012

August 28, 2015

28.510

$1,709.97

2% NSR to Franco Nevada & 1% Goldcorp

Massicotte

February 6, 2012

August 28, 2015

49.370

$2,961.10

2% NSR to Franco Nevada & 1% Goldcorp

Massicotte

February 6, 2012

August 28, 2015

49.710

$2,981.50

2% NSR to Franco Nevada & 1% Goldcorp

Massicotte

February 6, 2012

August 28, 2015

49.990

$2,998.29

2% NSR to Franco Nevada & 1% Goldcorp

Massicotte

February 6, 2012

August 28, 2015

3.960

$237.51

2% NSR to Franco Nevada & 1% Goldcorp

West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake

2% NSR to Franco Nevada & 1% Goldcorp

Appendix A-3

Detour Lake Mine NI 43-101 Technical Report

Claim #/Lease/Patent 2329567 2329568 2329569 2329570 2329571 2329572 2329573 3001876 3001877 3001878 3001879 3001885 3013358 3013359 3013360 3013361 3013365 3016452 3016453 3016454 3016455 3016456 3016457 3016458 3016459 3016460 3016461 3016462 3016463 3016470 3017747 4253050 4254624 4254625 4254626 4254627 4254628 4254629 4254630 4257401 4257402 4257403 4257404 4257405 4257406 4257407 4257408 4257409

Ownership Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation

Township/Area

Recorded Date

DueDate/Expiry

Area (Ha)

Work Credits Required

NSR/NPI

Massicotte

February 6, 2012

August 28, 2015

28.910

$1,733.96

2% NSR to Franco Nevada & 1% Goldcorp

Massicotte

February 6, 2012

August 28, 2015

28.940

$1,735.75

2% NSR to Franco Nevada & 1% Goldcorp

Massicotte

February 6, 2012

August 28, 2015

29.120

$1,746.55

2% NSR to Franco Nevada & 1% Goldcorp

Massicotte

February 6, 2012

August 28, 2015

25.480

$1,528.23

2% NSR to Franco Nevada & 1% Goldcorp

Massicotte

February 6, 2012

August 28, 2015

9.680

$580.58

2% NSR to Franco Nevada & 1% Goldcorp

Massicotte

February 6, 2012

May 4, 2015

12.190

$796.74

2% NSR to Franco Nevada & 1% Goldcorp

Massicotte

February 6, 2012

May 4, 2015

3.110

$203.26

2% NSR to Franco Nevada & 1% Goldcorp

June 3, 2002

June 3, 2015

32.000

$800.00

June 3, 2002

June 3, 2015

256.000

$6,400.00

June 3, 2002

June 3, 2015

128.000

$3,200.00

October 25, 2002

October 25, 2014

128.000

$3,200.00

October 25, 2002

October 25, 2014

224.000

$5,600.00

Lower Detour Lake

October 14, 2003

October 14, 2014

240.000

$6,000.00

2% NSR to Franco Nevada & 1% Goldcorp

Lower Detour Lake

October 14, 2003

October 14, 2014

224.000

$5,600.00

2% NSR to Franco Nevada & 1% Goldcorp

Lower Detour Lake

October 14, 2003

October 14, 2014

64.000

$1,600.00

2% NSR to Franco Nevada & 1% Goldcorp

Lower Detour Lake

October 14, 2003

October 14, 2014

224.000

$5,600.00

2% NSR to Franco Nevada & 1% Goldcorp

Lower Detour Lake

October 14, 2003

October 14, 2014

96.000

$2,400.00

2% NSR to Franco Nevada & 1% Goldcorp

Lower Detour Lake

March 11, 2004

March 11, 2015

256.000

$6,400.00

Lower Detour Lake

March 11, 2004

March 11, 2015

224.000

$5,600.00

Lower Detour Lake

March 11, 2004

March 11, 2015

80.000

$2,000.00

Lower Detour Lake

March 11, 2004

March 11, 2015

224.000

$5,600.00

Lower Detour Lake

March 11, 2004

March 11, 2015

256.000

$6,400.00

Lower Detour Lake

March 11, 2004

March 11, 2015

128.000

$3,200.00

Lower Detour Lake

March 11, 2004

March 11, 2015

240.000

$6,000.00

Lower Detour Lake

March 11, 2004

March 11, 2015

240.000

$6,000.00

Lower Detour Lake

March 11, 2004

March 11, 2015

256.000

$6,400.00

Lower Detour Lake

March 11, 2004

March 11, 2015

256.000

$6,400.00

Lower Detour Lake

March 11, 2004

March 11, 2015

256.000

$6,400.00

Lower Detour Lake

March 11, 2004

March 11, 2015

208.000

$5,200.00

West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake

Lower Detour Lake

March 11, 2004

March 11, 2015

16.000

$400.00

Hopper Lake

August 31, 2004

August 31, 2015

240.000

$6,000.00

March 3, 2010

March 3, 2014

16.000

$400.00

March 3, 2010

March 3, 2014

16.000

$400.00

West of Sunday Lake West of Sunday Lake West of Sunday Lake

March 3, 2010

March 3, 2014

256.000

$6,400.00

Hopper Lake

March 3, 2010

March 3, 2014

160.000

$4,000.00

Hopper Lake

March 3, 2010

March 3, 2018

256.000

$6,400.00

Hopper Lake

March 3, 2010

March 3, 2018

160.000

$4,000.00

Hopper Lake

March 3, 2010

March 3, 2018

32.000

$800.00

Hopper Lake

March 3, 2010

March 3, 2018

16.000

$400.00

Sunday Lake

April 26, 2010

April 26, 2014

256.000

$6,400.00

Sunday Lake

April 26, 2010

April 26, 2014

256.000

$6,400.00

Sunday Lake

April 26, 2010

April 26, 2014

256.000

$6,400.00

Sunday Lake

April 26, 2010

April 26, 2014

256.000

$6,400.00

Sunday Lake

April 26, 2010

April 26, 2014

256.000

$6,400.00

Sunday Lake

April 26, 2010

April 26, 2014

256.000

$6,400.00

Sunday Lake

April 26, 2010

April 26, 2014

256.000

$6,400.00

Sunday Lake

April 26, 2010

April 26, 2015

256.000

$6,400.00

Sunday Lake

April 26, 2010

April 26, 2015

256.000

$6,400.00

Appendix A-4

Detour Lake Mine NI 43-101 Technical Report

Claim #/Lease/Patent 4257410 4257411 4257412 4257413 4257414 4257415 4257416 4257417 4257418 4257419 4257420 4257421 4257422 4257423 4257424 4257425 4257426 4257427 4257428 4257429 4257430 4257431 4257432 4257433 4257434 4257435 4257436 4257437 4257438 4257439 4257440 4257441 4257442 4257443 4257444 4258324 4258325 4258326 4258327 4258328 4258329 4258330 4258331 4258332 4258333 4258381 4258382 4258383

Ownership Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation

Township/Area

Recorded Date

DueDate/Expiry

Area (Ha)

Work Credits Required

Sunday Lake

April 26, 2010

April 26, 2015

256.000

$6,400.00

Sunday Lake

April 26, 2010

April 26, 2015

256.000

$6,400.00

Sunday Lake

April 26, 2010

April 26, 2015

256.000

$6,400.00

Sunday Lake

April 26, 2010

April 26, 2015

256.000

$6,400.00

Sunday Lake

April 26, 2010

April 26, 2015

256.000

$6,400.00

Sunday Lake

April 26, 2010

April 26, 2015

256.000

$6,400.00

Sunday Lake

April 26, 2010

April 26, 2015

256.000

$6,400.00

Sunday Lake

April 26, 2010

April 26, 2015

80.000

$2,000.00

Sunday Lake

April 26, 2010

April 26, 2015

256.000

$6,400.00

Sunday Lake

April 26, 2010

April 26, 2015

256.000

$6,400.00

Sunday Lake

April 26, 2010

April 26, 2015

256.000

$6,400.00

Sunday Lake

April 26, 2010

April 26, 2015

256.000

$6,400.00

Sunday Lake

April 26, 2010

April 26, 2015

208.000

$5,200.00

Sunday Lake

April 26, 2010

April 26, 2015

256.000

$6,400.00

Sunday Lake

April 26, 2010

April 26, 2015

256.000

$6,400.00

Sunday Lake

April 26, 2010

April 26, 2015

256.000

$6,400.00

Sunday Lake

April 26, 2010

April 26, 2015

256.000

$6,400.00

Sunday Lake

April 26, 2010

April 26, 2015

256.000

$6,400.00

Sunday Lake

April 26, 2010

April 26, 2015

192.000

$4,800.00

Sunday Lake

April 26, 2010

April 26, 2015

160.000

$4,000.00

Sunday Lake

April 26, 2010

April 26, 2015

240.000

$6,000.00

Sunday Lake

April 26, 2010

April 26, 2015

240.000

$6,000.00

Sunday Lake

April 26, 2010

April 26, 2015

192.000

$4,800.00

Sunday Lake

April 26, 2010

April 26, 2015

208.000

$5,200.00

Sunday Lake

April 26, 2010

April 26, 2015

208.000

$5,200.00

April 26, 2010

April 26, 2015

208.000

$5,200.00

April 26, 2010

April 26, 2015

16.000

$400.00

April 26, 2010

April 26, 2015

240.000

$6,000.00

April 26, 2010

April 26, 2015

240.000

$6,000.00

April 26, 2010

April 26, 2015

240.000

$6,000.00

April 26, 2010

April 26, 2015

240.000

$6,000.00

April 26, 2010

April 26, 2015

240.000

$6,000.00

April 26, 2010

April 26, 2015

240.000

$6,000.00

April 26, 2010

April 26, 2015

240.000

$6,000.00

April 26, 2010

April 26, 2015

224.000

$5,600.00

Hopper Lake

August 20, 2010

August 20, 2014

160.000

$4,000.00

Hopper Lake

August 20, 2010

August 20, 2015

240.000

$6,000.00

Hopper Lake

August 20, 2010

August 20, 2015

256.000

$6,400.00

Hopper Lake

August 20, 2010

August 20, 2015

256.000

$6,400.00

Hopper Lake

August 20, 2010

August 20, 2015

240.000

$6,000.00

Hopper Lake

August 20, 2010

August 20, 2015

256.000

$6,400.00

Hopper Lake

August 20, 2010

August 20, 2015

240.000

$6,000.00

Hopper Lake

August 20, 2010

August 20, 2015

256.000

$6,400.00

Hopper Lake

August 20, 2010

August 20, 2015

224.000

$5,600.00

Hopper Lake

August 20, 2010

August 20, 2015

256.000

$6,400.00

August 20, 2010

August 20, 2015

240.000

$6,000.00

August 20, 2010

August 20, 2015

240.000

$6,000.00

August 20, 2010

August 20, 2015

240.000

$6,000.00

West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake

West of Sunday Lake West of Sunday Lake Hopper Lake

NSR/NPI

Appendix A-5

Detour Lake Mine NI 43-101 Technical Report

Claim #/Lease/Patent 4258384 4264629 4264630 4264631 4264632 4264633 4264634 4264635 4264636 4264637 4267601 4267602 4267603 4267604 4267605 4267606 4267607 4267608 4270250 4270251 4270252 4270253 4270254 4270255 4270256 4270257 4270258 4270370 4270371 4270372 4270373 4270374 4270375 4270376 4270377 4270378 4270379 4270383 4270384 4270385 4270386 4270387 4270388 4270389 4270410 4270411 4270413 4270414

Ownership

Township/Area

Recorded Date

DueDate/Expiry

Area (Ha)

Work Credits Required

Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation

West of Sunday Lake

August 20, 2010

August 20, 2015

240.000

$6,000.00

Hopper Lake

September 8, 2011

September 8, 2014

224.000

$5,600.00

Hopper Lake

September 8, 2011

September 8, 2014

128.000

$3,200.00

Hopper Lake

September 8, 2011

September 8, 2014

256.000

$6,400.00

Hopper Lake

September 8, 2011

September 8, 2014

256.000

$6,400.00

Hopper Lake

September 8, 2011

September 8, 2014

256.000

$6,400.00

Hopper Lake

September 8, 2011

September 8, 2014

256.000

$6,400.00

Hopper Lake

September 8, 2011

September 8, 2014

32.000

$800.00

Hopper Lake

September 8, 2011

September 8, 2014

64.000

$1,600.00

Lower Detour Lake

August 8, 2011

August 8, 2015

240.000

$6,000.00

Lower Detour Lake

August 8, 2011

August 8, 2015

256.000

$6,400.00

Lower Detour Lake

August 8, 2011

August 8, 2015

144.000

$3,600.00

Lower Detour Lake

August 8, 2011

August 8, 2015

128.000

$3,200.00

Lower Detour Lake

August 8, 2011

August 8, 2015

128.000

$3,200.00

Lower Detour Lake

August 8, 2011

August 8, 2015

112.000

$2,800.00

Lower Detour Lake

August 8, 2011

August 8, 2015

240.000

$6,000.00

Lower Detour Lake

August 8, 2011

August 8, 2015

256.000

$6,400.00

Lower Detour Lake

September 22, 2011

September 22, 2014

176.000

$4,400.00

Lower Detour Lake

October 9, 2012

October 9, 2014

176.000

$4,400.00

Lower Detour Lake

October 9, 2012

October 9, 2014

176.000

$4,400.00

Lower Detour Lake

October 9, 2012

October 9, 2014

176.000

$4,400.00

Lower Detour Lake

October 9, 2012

October 9, 2014

208.000

$5,200.00

Lower Detour Lake

October 9, 2012

October 9, 2014

256.000

$6,400.00

Lower Detour Lake

October 9, 2012

October 9, 2014

256.000

$6,400.00

Lower Detour Lake

October 9, 2012

October 9, 2014

208.000

$5,200.00

Atkinson Lake

October 9, 2012

October 9, 2014

256.000

$6,400.00 $5,600.00

Atkinson Lake

October 9, 2012

October 9, 2014

224.000

Lower Detour Lake

April 19, 2013

April 19, 2015

48

$1,200.00

Lower Detour Lake

April 19, 2013

April 19, 2015

192

$4,800.00

Lower Detour Lake

April 19, 2013

April 19, 2015

256

$6,400.00

Lower Detour Lake

April 19, 2013

April 19, 2015

48

$1,200.00

Lower Detour Lake

April 19, 2013

April 19, 2015

144

$3,600.00

Lower Detour Lake

April 19, 2013

April 19, 2015

256

$6,400.00

Lower Detour Lake

April 19, 2013

April 19, 2015

144

$3,600.00

Lower Detour Lake

April 19, 2013

April 19, 2015

160

$4,000.00

Lower Detour Lake

April 19, 2013

April 19, 2015

256

$6,400.00

Lower Detour Lake

April 19, 2013

April 19, 2015

240

$6,000.00

Lower Detour Lake

April 19, 2013

April 19, 2015

256

$6,400.00

Atkinson Lake

April 19, 2013

April 19, 2015

256

$6,400.00

Atkinson Lake

April 19, 2013

April 19, 2015

256

$6,400.00

Atkinson Lake

April 19, 2013

April 19, 2015

256

$6,400.00

Atkinson Lake

April 19, 2013

April 19, 2015

176

$4,400.00

Atkinson Lake

April 19, 2013

April 19, 2015

160

$4,000.00

Atkinson Lake

April 19, 2013

April 19, 2015

160

$4,000.00

Atkinson Lake

April 19, 2013

April 19, 2015

160

$4,000.00

Atkinson Lake

April 19, 2013

April 19, 2015

192

$4,800.00

Atkinson Lake

April 19, 2013

April 19, 2015

256

$6,400.00

Atkinson Lake

April 19, 2013

April 19, 2015

256

$6,400.00

NSR/NPI

Appendix A-6

Detour Lake Mine NI 43-101 Technical Report

Claim #/Lease/Patent 4270415 4270416 4270417 4270418 4270419 4270420 4270421 4270422 4270423 4270424 CLM 228

CLM 229 CLM 230 CLM 231 CLM 232 CLM 233 CLM 234 CLM 235 CLM 236 CLM 237 CLM 238 CLM 239 CLM 240 CLM 340 * CLM 341 * CLM 342 * CLM 343 * CLM 344 * CLM 357 * CLM 358 * CLM 359 * CLM 360 * CLM 361 * CLM 396* CLM 484 CLM 485 CLM318 CLM319 CLM362 CLM363 CLM364 CLM491

CLM497

Ownership Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Tradewinds & Detour Gold Corporation Tradewinds & Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Tradewinds & Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation

Detour Gold Corporation

Work Credits Required

Township/Area

Recorded Date

DueDate/Expiry

Area (Ha)

Atkinson Lake

April 19, 2013

April 19, 2015

256

$6,400.00

Atkinson Lake

April 19, 2013

April 19, 2015

256

$6,400.00

Atkinson Lake

April 19, 2013

April 19, 2015

256

$6,400.00

Atkinson Lake

April 19, 2013

April 19, 2015

256

$6,400.00

Atkinson Lake

April 19, 2013

April 19, 2015

256

$6,400.00

Atkinson Lake

April 19, 2013

April 19, 2015

64

$1,600.00

Atkinson Lake

April 19, 2013

April 19, 2015

256

$6,400.00

Atkinson Lake

April 19, 2013

April 19, 2015

256

$6,400.00

Atkinson Lake

April 19, 2013

April 19, 2015

256

$6,400.00

Atkinson Lake

April 19, 2013

April 19, 2015

256

$6,400.00

West of Sunday Lake

March 31, 2023

281.932

2% NSR to Franco Nevada .

West of Sunday Lake

March 31, 2023

349.786

2% NSR to Franco Nevada .

Sunday Lake

February 28, 2023

331.025

2% NSR to Franco Nevada .

Sunday Lake

February 28, 2023

301.960

2% NSR to Franco Nevada .

Sunday Lake

February 28, 2023

424.127

2% NSR to Franco Nevada .

Sunday Lake

February 28, 2023

352.267

2% NSR to Franco Nevada .

Sunday Lake & Lower Detour Lake

February 28, 2023

370.870

2% NSR to Franco Nevada .

Sunday Lake

March 31, 2023

268.654

2% NSR to Franco Nevada .

Sunday Lake

March 31, 2023

274.446

2% NSR to Franco Nevada .

Sunday Lake

March 31, 2023

391.594

2% NSR to Franco Nevada .

Sunday Lake

March 31, 2023

199.498

2% NSR to Franco Nevada .

Sunday Lake

March 31, 2023

404.868

2% NSR to Franco Nevada .

Sunday Lake

March 31, 2023

460.265

2% NSR to Franco Nevada .

Lower Detour Lake

May 31, 2012

769.336

7.5% NPI to Prism Resources Inc.

Lower Detour Lake

May 31, 2012

452.078

7.5% NPI to Prism Resources Inc.

Lower Detour Lake

May 31, 2012

501.713

7.5% NPI to Prism Resources Inc.

Lower Detour Lake

May 31, 2012

540.955

7.5% NPI to Prism Resources Inc.

Lower Detour Lake

May 31, 2012

627.089

7.5% NPI to Prism Resources Inc.

Lower Detour Lake

May 31, 2033

418.040

7.5% NPI to Prism Resources Inc.

Lower Detour Lake

February 28, 2018

715.593

7.5% NPI to Prism Resources Inc.

Lower Detour Lake

May 31, 2012

367.580

7.5% NPI to Prism Resources Inc.

Lower Detour Lake

May 31, 2012

585.046

7.5% NPI to Prism Resources Inc.

Lower Detour Lake

May 31, 2012

391.019

7.5% NPI to Prism Resources Inc.

West of Sunday Lake

May 31, 2033

308.840

2% NSR to Franco Nevada .

W of Sunday Lake & Hopper Lake W of Sunday Lake & Sunday Lake Hopper Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake West of Sunday Lake Lower Detour Lake

Lower Detour Lake

June 30, 2033

137.528

November 30, 2033

4,652.944

September 30, 2031

31.517

October 31, 2031

41.877

December 31, 2032

448.100

December 31, 2032

276.105

December 31, 2032

279.185

June 30, 2033

274.387

1,792.772

NSR/NPI

Claim 1154730, 2% NSR to Franco Nevada & 1% Goldcorp

Claims 951001 to 951019 incl., 951026, 951050, 1088666 to 1088675 incl., 1090057 to 1090074 incl. and 3016464 subject to 7.5% NPI to Prism Resources Inc. Claims 1133206 to 1133209 incl. and 1160141 to 1160144 incl. subject to 2% NSR to Franco Nevada & 1% Goldcorp

Appendix A-7

Detour Lake Mine NI 43-101 Technical Report

Claim #/Lease/Patent

CLM498

P1087168* P1087169* P1087170* P1087171* P1087172* P1087173* P1087174* P1087175* P1087176* P400974 P400975 P400976 P400977 P400978 P400979 P401008 P401009 P401014 P421282 P421283 P421284 P421381 P421382 P421383 P421384 P421386 P421387 P421388 P421389 P421391 P421392 P421393 P421394 P524182 * P524183* P524184* P524187* P524188* P524189* P524192* P524194* P524242* P524247* P524248*

Ownership

Detour Gold Corporation

Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation

Township/Area

Recorded Date

DueDate/Expiry

Lower Detour Lake

Area (Ha)

Work Credits Required

NSR/NPI

1,360.960

Claims 951020, 951024 to 951035 inclusive, 951037 to 951040 inclusive, 956232, 956233, 1204468, 1204528, 1204529 & 1204533 subject to 7.5% NPI to Prism Resources Inc. Claim 1213438 subject to 2% NSR to Franco Nevada & 1% Goldcorp, Claims 3016449 to 3016451 Free & Clear

145.861

7.5% NPI to Prism Resources Inc.

Hopper Lake

May 31, 2013

Hopper Lake

May 31, 2013

7.5% NPI to Prism Resources Inc.

Hopper Lake

May 31, 2013

7.5% NPI to Prism Resources Inc.

Hopper Lake

May 31, 2013

7.5% NPI to Prism Resources Inc.

Hopper Lake

May 31, 2013

7.5% NPI to Prism Resources Inc.

Hopper Lake

May 31, 2013

7.5% NPI to Prism Resources Inc.

Hopper Lake

May 31, 2013

7.5% NPI to Prism Resources Inc.

Hopper Lake

May 31, 2013

7.5% NPI to Prism Resources Inc.

Hopper Lake

May 31, 2013

Sunday Lake

7.5% NPI to Prism Resources Inc. 205.928

2% NSR to Franco Nevada .

Sunday Lake

2% NSR to Franco Nevada .

Sunday Lake

2% NSR to Franco Nevada .

Sunday Lake

2% NSR to Franco Nevada .

Sunday Lake

April 30, 2019

Sunday Lake

April 30, 2019

269.160

2% NSR to Franco Nevada . 2% NSR to Franco Nevada .

Sunday Lake

2% NSR to Franco Nevada .

Sunday Lake

2% NSR to Franco Nevada .

Sunday Lake

2% NSR to Franco Nevada .

Sunday Lake

2% NSR to Franco Nevada .

Sunday Lake

2% NSR to Franco Nevada .

Sunday Lake

April 30, 2019

2% NSR to Franco Nevada .

Sunday Lake

April 30, 2019

2% NSR to Franco Nevada .

Sunday Lake

April 30, 2019

2% NSR to Franco Nevada .

Sunday Lake

April 30, 2019

2% NSR to Franco Nevada .

Sunday Lake

April 30, 2019

2% NSR to Franco Nevada .

Sunday Lake

April 30, 2019

2% NSR to Franco Nevada .

Sunday Lake

April 30, 2019

2% NSR to Franco Nevada .

Sunday Lake

2% NSR to Franco Nevada .

Sunday Lake

2% NSR to Franco Nevada .

Sunday Lake

April 30, 2019

2% NSR to Franco Nevada .

Sunday Lake

April 30, 2019

2% NSR to Franco Nevada .

Sunday Lake

April 30, 2019

2% NSR to Franco Nevada .

Sunday Lake

April 30, 2019

2% NSR to Franco Nevada .

Hopper Lake

May 31, 2012

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

728.183

2% NSR to Franco Nevada & 1% Goldcorp

Appendix A-8

Detour Lake Mine NI 43-101 Technical Report

Claim #/Lease/Patent P524249* P524270* P524271* P524272* P524275* P524276* P524277* P524280* P524281* P524282* P524285* P524286* P524287* P524290* P524291* P524292* P524295* P524296* P524297* P524302* P524303* P524304* P524305* P524306* P524307* P524308* P524309* P524310* P524311* P524312* P524313* P524314* P524315* P524316* P524317* P549852 P549853 P549854 P549855 P549856 P549857 P549858 P549859 P549860 P549861 P549862 P549863 P549864

Ownership Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation

Township/Area

Recorded Date

DueDate/Expiry

Area (Ha)

Work Credits Required

NSR/NPI

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Hopper Lake

May 31, 2012

2% NSR to Franco Nevada & 1% Goldcorp

Sunday Lake

April 30, 2030

Sunday Lake

April 30, 2030

7.5% NPI to Prism Resources Inc.

Sunday Lake

April 30, 2030

7.5% NPI to Prism Resources Inc.

Sunday Lake

April 30, 2030

7.5% NPI to Prism Resources Inc.

Sunday Lake

April 30, 2030

7.5% NPI to Prism Resources Inc.

Sunday Lake

April 30, 2030

7.5% NPI to Prism Resources Inc.

Sunday Lake

April 30, 2030

7.5% NPI to Prism Resources Inc.

Sunday Lake

April 30, 2030

7.5% NPI to Prism Resources Inc.

Sunday Lake

April 30, 2030

7.5% NPI to Prism Resources Inc.

Sunday Lake

April 30, 2030

7.5% NPI to Prism Resources Inc.

Sunday Lake

April 30, 2030

7.5% NPI to Prism Resources Inc.

Sunday Lake

April 30, 2030

7.5% NPI to Prism Resources Inc.

Sunday Lake

April 30, 2030

7.5% NPI to Prism Resources Inc.

332.219

7.5% NPI to Prism Resources Inc.

Appendix A-9

Detour Lake Mine NI 43-101 Technical Report

Claim #/Lease/Patent P549865 P549866 P549867 P549868 P549869 P549870 P549871 P549872 P549873 P549874 P549875 P549876 P549877 P549878 P549879 P549880 P549881 P549882 P549883 P549884 P549885 P549886 P549887 P549888 P549889 P549890 P549891 P553663 P553664 P553665 P553666 P553667 P553668 P553669 P553670 P553740 P553741 P553742 P553743 P553744 P553745 P553746 P553747 P553748 P553749 P553750 P553751 P553752

Ownership Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation

Township/Area

Recorded Date

DueDate/Expiry

Area (Ha)

Work Credits Required

NSR/NPI

Sunday Lake

April 30, 2030

7.5% NPI to Prism Resources Inc.

Sunday Lake

April 30, 2030

7.5% NPI to Prism Resources Inc.

Sunday Lake

April 30, 2030

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

501.624

487.310

7.5% NPI to Prism Resources Inc.

7.5% NPI to Prism Resources Inc.

Appendix A-10

Detour Lake Mine NI 43-101 Technical Report

Claim #/Lease/Patent P553753 P553754 P553755 P553756 P553757 P553758 P553759 P568937 P568938 P568939 P568940 P568941 P568942 P568943 P568944 P568945 P576730 P576731 P576732 P576733 P576734 P576735 P609948 P609949 P609950 P609951 RW306 RW307 Part 1 RW307 Part 2 RW308 RW309

Note

Ownership Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation Detour Gold Corporation

Township/Area

Recorded Date

DueDate/Expiry

Area (Ha)

Work Credits Required

NSR/NPI

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Lower Detour Lake

December 31, 2028

Lower Detour Lake

December 31, 2028

7.5% NPI to Prism Resources Inc.

Lower Detour Lake

December 31, 2028

7.5% NPI to Prism Resources Inc.

Lower Detour Lake

December 31, 2028

7.5% NPI to Prism Resources Inc.

Lower Detour Lake

December 31, 2028

7.5% NPI to Prism Resources Inc.

Lower Detour Lake

December 31, 2028

7.5% NPI to Prism Resources Inc.

Lower Detour Lake

December 31, 2028

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2028

7.5% NPI to Prism Resources Inc.

137.565

7.5% NPI to Prism Resources Inc.

Sunday Lake

December 31, 2028

7.5% NPI to Prism Resources Inc.

Lower Detour Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Lower Detour Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Lower Detour Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Lower Detour Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Lower Detour Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Lower Detour Lake

December 31, 2031

7.5% NPI to Prism Resources Inc.

Sunday Lake

April 30, 2030

7.5% NPI to Prism Resources Inc.

Sunday Lake

April 30, 2030

7.5% NPI to Prism Resources Inc.

Sunday Lake

April 30, 2030

7.5% NPI to Prism Resources Inc.

Sunday Lake

April 30, 2030

7.5% NPI to Prism Resources Inc.

Sunday Lake

43.949

2% NSR to Franco Nevada .

Sunday Lake & Lower Detour Lake

42.014

2% NSR to Franco Nevada .

Sunday Lake

18.947

2% NSR to Franco Nevada .

Sunday Lake

59.448

2% NSR to Franco Nevada .

Sunday Lake

232.124

2% NSR to Franco Nevada .

62,669.000

Ontario Leasehold Lands Mining Leases are now the primary form of Crown grant for mining purposes. Leases are issued for either 10‐year or 21‐year terms.  Rent is applied to mining leases. Freehold patented mining lands are lands originally granted for mining purposes, or mining rights that were severed from the surface rights after their original grant.  Patented mining lands are liable to mining land tax.  * Mining Lease Renewals Approved by MNDM, requisitions sent to MNR for issuance of renewal mining leases February 27, 2013. New expiry dates to be established upon execution of renewal lease documents Ontario Patented Lands

Appendix A-11

Quebec

Ontario

Sunday Lake (50% JV)

0

5 kilometres

10

Detour Lake Property Scale 1:125,000

December 2013

Detour Lake Mine NI 43-101 Technical Report

Appendix B

ASL Report (L. Bloom, March 17, 2013)

B-1

REVIEW OF THE DETOUR LAKE PROJECT (ONTARIO) ASSAY QUALITY CONTROL PROGRAM FOR BLOCK A AREA (JANUARY – DECEMBER 2012) Prepared on behalf of Detour Gold Corp.

March 17, 2013

Analytical Solutions Ltd. 1403-3230 Yonge Street, Toronto, Ontario M4N 3P6 T: 416.462.9124

Analytical Solutions Ltd.

F: 647.438.6068 www.explorationgeochem.com

Executive Summary Approximately 61,000 samples from 134 DBKA12 drill holes and 22 TWDDH extensions totaling 44,637 m and 4,521 m respectively (DBKA12-0001 through DBKA12-0130) were collected and assayed from January to December 2012 for the drill program at the Block A area. The quality control program February 2012 onwards consists of: a) insertion of a coarse blank one in every 40 samples; b) insertion of a reference material one in every 40 samples; c) routine duplicate assays of pulps as part of laboratory QC protocols; d) insertion of a preparation duplicate samples one in every 30 samples; and e) insertion of a duplicate drill core sample one in every 40 samples. Samples were prepared at the SGS sample preparation facility in Sudbury and analyzed at SGS Laboratories, Toronto, Canada (“Don Mills”). All data were provided in Excel spreadsheets by Madeline Thon. There is no evidence of systematic gold contamination based on the 1,362 blanks that were inserted with samples. Reference materials from CDN Laboratories (Canada) were submitted a total of 46 times with Trade Winds samples sent to ActLabs in January 2012. From February 2012 onwards, RMs from OREAS (Australia) were submitted a total of 1,448 times with samples sent to SGS. The failure rate was at an expected level except for the period May to December, when failure rate for RMs with less than 1 g/t Au was up to 15%. Appropriate action was taken, including requests for repeat assays, for the QC failures. The failure rate is a result of a low overall bias between May to December, estimated at 4- 5% for the low grade range. It is expected that this could add conservatism to the resource estimate. Data for pulp, preparation and core duplicates were reviewed, as well as 50 gm versus screened metallic assays. The reproducibility for the duplicates in the current period is similar to previous periods and within expected ranges. There is no bias evident between original and duplicate halves of the drill core. A total of 205 sample pulps and 200 drill core samples (not including QC samples) were submitted to SGS Cochrane for check assays (original samples were assayed at SGS Don Mills). RMs submitted to SGS Cochrane were generally biased low. The SGS Cochrane and Don Mills assays generally showed good agreement and it is assumed that a bias towards low values at SGS Cochrane, relative to Don Mills, is due to start-up problems experienced by SGS Cochrane. SGS Don Mills laboratory will close April 2013 and future gold assaying will be done at the SGS facility in Peterborough. An audit of the new facility is warranted if Detour plans to use SGS for exploration assays.

Analytical Solutions Ltd.

Table of Contents 1.0 Introduction ............................................................................................................................................ 1 2.0 Sample Handling, Preparation, Quality Control and Assay Procedures ................................................. 2 2.1

Sample Handling ........................................................................................................................... 2

2.2

Sample Preparation and Assaying................................................................................................. 3

3.0 Accuracy as Determined by Blanks and Reference Materials................................................................. 5 3.1

Laboratory Performance for Blank Samples ................................................................................. 5

3.2

Laboratory Performance Based on Reference Materials and Control Samples ........................... 6

4.0 Laboratory Pulp Duplicates ................................................................................................................... 15 5.0 Preparation Duplicates ......................................................................................................................... 17 6.0 Drill Core Duplicate Samples ................................................................................................................. 20 7.0 Screen Metallic Assays .......................................................................................................................... 22 8.0 Check Assays at Secondary Laboratory................................................................................................. 25 8.1

Check Assays done on Pulp Samples .......................................................................................... 25

8.2

Check Assays done on Core Samples .......................................................................................... 28

9.0 Laboratory Audit ................................................................................................................................... 32 10.0 Conclusions ......................................................................................................................................... 33

List of Tables Table 3.2.1:

Summary of Reference Materials at ActLabs

Table 3.2.2:

Summary of Reference Materials at SGS (all samples)

Table 3.2.2-a:

Summary of Reference Materials at SGS (February to May 2012)

Table 3.2.2-b: Summary of Reference Materials at SGS (June 2012 onwards) Table 3.2.3:

List of Additional QC Failures for RMs

Table 4.1:

Precision for Laboratory Pulp Duplicate Pairs

Table 5.1:

Percentage of Preparation Duplicate Pairs Reporting Within Specific Ranges for Gold Assays

Table 5.1:

Precision for Preparation Duplicate Pairs

Table 6.1:

Summary of Gold Assays for Core Duplicates

Table 6.2:

Summary Percentage of Core Duplicate Pairs Reporting Within Specific Ranges

Table 7.1:

Comparison of Gold by Fire Assay and Screen Metallics (selected on the basis of VG)

3 Analytical Solutions Ltd.

Table 7.2:

Comparison of Gold by Fire Assay and Screen Metallics (selected on the basis of Original Fire Assay Au >5 g/t)

Table 8.1.1:

Summary of RMs Inserted with Check Assays

Table 8.1.2:

QC Failure for RMs Inserted with Check Assays

Table 8.1.3:

Summary of Check Assays

Table 8.2.1:

Summary of RMs Inserted with Other Half Core Check Assays

Table 8.2.2:

Summary of Other Half Core Check Assays

List of Figures Figure 3.1.1:

Assays for Blanks

Figure 3.2.1:

Percent of Expected for Gold Results for CDN Reference Materials

Figure 3.2.2:

Percent of Expected for Gold Results for OREAS Reference Materials

Figure 3.2.3:

z-scores for Gold Results for OREAS Reference Materials

Figure 4.1:

Laboratory Pulp Duplicates

Figure 5.1:

Comparison of Gold Assays for Preparation Duplicates

Figure 5.2:

Summary of Reproducibility for Preparation Duplicates

Figure 6.1:

Comparison of Gold Assays for Drill Core Duplicates

Figure 7.1:

Comparison of Gold by Fire Assay and Screen Metallics (selected on the basis of VG)

Figure 7.2:

Comparison of Gold by Fire Assay and Screen Metallics (selected on the basis of Original Fire Assay Au >5 g/t)

Figure 8.1.1:

RMs Inserted with Check Assays

Figure 8.1.2:

Check Assays for Gold (g/t)

Figure 8.1.3:

Comparison of Check Assays and Laboratory Pulp Duplicates

Figure 8.2.1:

RMs Inserted with Other Half Core Check Assays

Figure 8.2.2:

Other Half Core Check Assays for Gold (g/t)

List of Appendices Appendix 1:

Graphs for Individual RMs (includes all reported values including failures)

Appendix 2:

List of QC Failures for RMs

Appendix 3:

Graphs for Laboratory Pulp Duplicates

Appendix 4:

Graphs for Preparation Duplicates

Appendix 5:

Graphs for Drill Core Duplicates

Appendix 6

Selected Gold Assays for Core Duplicates

4 Analytical Solutions Ltd.

1.0 Introduction The Detour Lake property is located mainly in northeastern Ontario, approximately 300 kilometres northeast of Timmins and 185 kilometres by road northeast of Cochrane. The average grade of the deposit is approximately 1 g/t gold and the cut-off grade is 0.5 g/t gold. Detour Gold’s first exploration priority is to advance the Block A near-surface deposit to the prefeasibility stage. The Block A near-surface deposit is located less than 1 kilometre northwest of the Detour Lake open pit. Detour Gold completed the acquisition of Trade Winds Ventures in December 2011 to acquire the remaining 50% of Block A that it did not control and 100% of the Gowest property (located just west of Block A). To date, 180,000 metres of drilling has been completed on Block A, of which 112,189 metres was by Trade Winds between 2007 and 2011. In December 2010, Trade Winds reported an indicated resource of approximately 1.9 million ounces (70.8 million tonnes grading 0.85 g/t) and an additional 762,000 ounces in the inferred category (27.3 million tonnes grading 0.87 g/t). In January 2012, Detour Gold initiated a pre-feasibility study and a 50,000 metre drilling program on a 40x40 metre spacing from sections 15,300E to 16,780E. The geology of the Block A deposit is similar to Detour Lake with Detour's mineralized domains continuing into Block A. Gold mineralization is found in swarms of steeply dipping quartz veins, mainly within pillow flows (65%) and massive flows (15%). A Chloritic Greenstone Unit (M-Zone) (15%) also hosts mineralized quartz veins, and has been traced over more than 3 km. Samples were prepared at SGS facilities in Sudbury and analyzed at SGS Laboratories, (Don Mills) Toronto, Canada (“SGS Don Mills). Analytical Solutions Ltd (“ASL”) reviewed the assay Quality Control (“QC”) program. Data were provided in a series of Excel spreadsheets by Detour Gold Corporation. ASL has not performed any validation of the data with regards to data entry or transfer from SGS files. The objective of this report is to document the quality control practices and results, and to identify any systemic bias in the assays or sources of contamination.

1 Analytical Solutions Ltd.

2.0 Sample Handling, Preparation, Quality Control and Assay Procedures 2.1

Sample Handling

The following procedure was provided to ASL in a Word document “Detour Gold Corp Core Handling.doc” by Roger Aubertin. “Core Handling Drill core is packed into wooden core trays on site, with the depths of each run marked on wooden blocks and inserted into the trays. These trays are collected by Detour geo technicians and delivered to the geology shacks on site. Core handling consists of: • • • • • • • • • • • •

Geological logging Lithology, veining, mineralization, alteration, structure Marking out samples Measuring core recoveries/RQD’s Photographing core/tagging boxes with hole id’s and meterage Measuring rock strengths Marking out fractures Marking meter intervals between runs Cutting core for sampling Sampling core Shipping Racking and storage

All logging and marking of samples is done by Detour geologists. Photographing, recovery, fractures, and rock strengths measurements are carried out by geo technicians under geological supervision. Core is logged by Detour geologists according to the existing lithology code system established for incorporation into Datamine with existing historical data. Core recovery, RQD, rock strength, and fractures are recorded for each borehole, and all core is photographed to preserve a permanent record. All data entry is done on individual databases capable of synchronizing with a master database through the Detour Gold Corp network. These individual databases are synchronized daily. All core is systematically sampled, following the procedure outlined below: • • •

Mineralized/potentially mineralized zones are recorded. Visible gold broken down into half meter samples for pulp metallic analyses. Core is fitted together in the box, and a wax pencil is used to scribe a line along the core, using the core box edge as a guide. The scribe line is used to orient the core in the diamond saw, and the same half of the core, the exposed upper portion, is always put in the sample bag. The portion to be saved is fitted back into the core box to be kept as a permanent record.

2 Analytical Solutions Ltd.

•

Samples are marked both on core and corresponding sample tags and bags. All core is sampled for entire borehole top to bottom in one meter intervals with the exception of pulp metallics, which are sampled at half-meter intervals. Samples are bagged and numbered by a lab technician and double checked by another lab technician for accuracy. All samples are logged with the sample number, from-to interval, and type of sample (rock or QAQC sample). Additional information such as lithology, mineralization and veining are subsequently merged with sample data. Samples are delivered to the sample preparation laboratory for shipping where they are checked again for accuracy before being released. The database is programmed to prompt the geologist during sampling to enter Standards, Blanks and Duplicates at certain intervals. These ensure quality control on site as well as the assay labs. Standards and Blanks are used by the lab technicians to check the sample bags and shipments for errors in sequencing. Lab technicians use sample reports generated by the database to verify correct standards and sequencing in samples. Shipments are also kept track of through the database, and it is capable of pulling any shipment report done by Detour Gold. Pulp metallics and specific gravity requests are highlighted for the lab technician while filing a shipment and totals are calculated to ensure accurate counts included in the batch.

• • •

• •

• •

All core is stored on site at the Detour exploration camp after logging, cutting, sampling and photography.”

2.2

Sample Preparation and Assaying

Samples were prepared at SGS Sudbury and analyzed at SGS Don Mills. The method codes were: SGS Code

Description

1

WGH79

Weight of samples upon arrival

2

CRU25

Sample preparation – crush to 90% passing 2 mm

3

PUL46

Pulverize 500 g in Cr steel to 85% passing 75 μm

4

PUL47

Pulverize 1.2 kg in Cr steel to 85% passing 75μm (for screen metallics only)

4

FAI525

50 g fire assay with ICP-AES finish (5 ppb to 100,000 ppb)

5

FAG505

6

FAS31K

50 g fire assay with gravimetric finish (for Au >100 ppm) Gold by Screen Metallics Fire Assay on 500 gm screened at 106 μm (for Au >5 g/t) – a second pulp is prepared from the reject

Samples with gold assays greater than 5 g/t Au were resubmitted for gold by screened metallics (FAMET). A second 500 gm sample is prepared from the reject and the 500 gm is pulverized to 90% passing 106 μm.

3 Analytical Solutions Ltd.

The quality control program consists of: a) b) c) d) e)

insertion of a coarse blank one in every 40 samples; insertion of a reference material one in every 40 samples; routine duplicate assays of pulps as part of laboratory QC protocols; insertion of a preparation duplicate samples one in every 30 samples; and insertion of a duplicate drill core sample one in every 40 samples.

4 Analytical Solutions Ltd.

3.0 Accuracy as Determined by Blanks and Reference Materials Coarse blanks and reference materials were submitted with samples. Prior to Detour Gold’s acquisition of Trade Winds Ventures, 665 samples (including QC samples) were submitted to ActLabs for assays. The table below shows the breakdown of samples. Trade Winds samples account for 1% of the total 2012 data. Operator

Laboratory

Trade Winds ActLabs Detour Gold SGS Totals

No .of Assays 610 57,692 58,302

No. of QAQC* 55 3,043 3,098

Total Samples 665 60,735 61,400

*QAQC includes Blanks, Standards and Duplicates

3.1

Laboratory Performance for Blank Samples

Barren coarse material (“a blank”) is submitted with samples for crushing and pulverizing to determine if there has been contamination or sample cross-contamination in preparation. Elevated values for blanks may also indicate sources of contamination in the fire assay procedure (contaminated reagents or crucibles) or sample solution carry-over during instrumental finish. As of August 2007, decorative white pebbles for gardening (~250 gm sample size) purchased at the local hardware store were used as blank material. This material was also assayed at Swastika Laboratory to test that the material was not gold-bearing. There were a total of 1,362 blanks submitted with the samples for analysis. Over 99% (1,346 out of 1,362 samples) of the blanks assayed less than 0.05 g/t, which is ten times the detection limit of 0.005 g/t (Figure 3.1.1) and are considered acceptable. There was one quality control failure based on blanks (less than 1% of the samples submitted for blanks) which was investigated and followed up by Madeline Thon (MT). Repeat assays have been requested where appropriate and were set to supersede original assays where appropriate. No further action is required. There is no evidence of systematic gold contamination based on the blanks that were inserted with samples.

5 Analytical Solutions Ltd.

Figure 3.1.1: Assays for Blanks

3.2

Laboratory Performance Based on Reference Materials and Control Samples

Reference Materials (“RM”) are submitted with samples for assay to identify: a)

if there were assay problems with specific sample batches; and

b)

possible long-term biases in the overall dataset.

The definition of a quality control failure is when: a)

assays for a RM are outside ±three standard deviations or 10%; and

b)

assays for two consecutive RMs are outside ±two standard deviations.

Five different RMs from CDN Laboratories (Canada) were submitted a total of 46 times with Trade Winds samples sent to ActLabs in January 2012.

6 Analytical Solutions Ltd.

From February 2012 onwards, five different RMs were used that are purchased from OREAS (Australia). These were submitted a total of 1,448 times with samples sent to SGS. The OREAS RMs are: (a) well homogenized, (b) assayed at more than 15 international mineral testing laboratories, and (c) are certified in accordance with International Standards Organization (ISO) recommendations.

Trade Winds-CDN RM Results Five different RMs from CDN Laboratories (Canada) were submitted a total of 46 times with Trade Winds samples sent to ActLabs in January 2012. The results are summarized in Table 3.2.1. Table 3.2.1: Summary of Reference Materials at ActLabs

RM CDN GS-4PA CDN GS-1H CDN GS-1P5D CDN GS-3J CDN GS-6B Total

Total N 10 6 9 10 11 46

Expected Au (g/t) Average Std. Dev. 0.438 0.013 0.972 0.041 1.470 0.059 2.710 0.080 6.450 0.101

Observed Au (g/t) Average Std. Dev. 0.431 0.010 0.963 0.077 1.481 0.076 2.729 0.163 6.457 0.157

% of Expected 98.5 99.1 100.8 100.7 100.1 * - Weighted Average 99.9*

QC Failures 4 0 1 1 0 6

* Weighted average does not include QC failures

The results were plotted and are shown in Figure 3.2.1. Quality control failures and mislabels are excluded from the graphs and calculations in these tables. For reference, the results for the individual RMs (with all reported values including failures) are plotted individually in Appendix 1. The lowest grade RM, CDN-GS-4PA, failed most often, with results generally biased high. Failed values ranged from 0.491 to 0.511 g/t Au. With the exclusion of results for GS-4PA, the failure rate was 5% and is within an acceptable range and the other RMs do not display a persistent bias.

7 Analytical Solutions Ltd.

Figure 3.2.1: Percent of Expected for Gold Results for CDN Reference Materials

SGS – ORE RM Results From February 2012 onwards, five different RMs from OREAS (Australia) were submitted a total of 1,448 times with samples sent to SGS. The results for the RMs are summarized in Table 3.2.2. Table 3.2.2: Summary of Reference Materials at SGS (all samples)

RM OREAS 15f OREAS 15g OREAS 15d OREAS 18c OREAS 10c Total

Total N 94 292 362 385 315 1,448

Expected Au (g/t) Average Std. Dev. 0.334 0.016 0.527 0.023 1.559 0.042 3.520 0.110 6.600 0.160

Observed Au (g/t) Average Std. Dev. 0.320 0.012 0.515 0.020 1.525 0.046 3.494 0.084 6.624 0.137

% of Expected 95.7 97.7 97.8 99.3 100.4 * - Weighted Average 98.6*

QC Failures 13 30 46 6 4 99

* Weighted average does not include QC failures

A summary of results for the RMs are plotted in Figures 3.2.2 and 3.2.3, only showing the acceptable results. 8 Analytical Solutions Ltd.

The Z-scores plotted in Figures 3.2.3 were calculated as the difference between the observed and expected assay divided by the expected standard deviation: z-score = (x - µ) / σ,

where:

x is the observed assay; μ is the expected assay for the RM; and σ is the expected standard deviation for the RM.

For reference, the results for the individual RMs (with all reported values including failures) are plotted individually in Appendix 1.

Figure 3.2.2: Percent of Expected for Gold Results for OREAS Reference Materials

9 Analytical Solutions Ltd.

Figure 3.2.3: z-scores for Gold Results for OREAS Reference Materials

It is apparent from the graphs that the laboratories performance changed during the year. Between February and May, SGS had a 3% error rate and only the highest grade RM (10c) showed a minor bias in the order of +2%. This is summarized below in Table 3.2.2-a. Table 3.2.2-a: Summary of Reference Materials at SGS (February to May 2012)

RM OREAS 15f OREAS 15g OREAS 15d OREAS 18c OREAS 10c Total

Total N 0 93 80 96 69 338

Expected Au (g/t) Average Std. Dev. 0.334 0.016 0.527 0.023 1.559 0.042 3.520 0.110 6.600 0.160

Observed Au (g/t) Average Std. Dev. n.a. n.a. 0.526 0.022 1.553 0.053 3.528 0.105 6.742 0.140 * - Weighted Average

% of Expected n.a. 99.7 99.6 100.2 102.1 100.3*

QC Failures n.a. 7 8 3 3 21

* Weighted average does not include QC failures

In the period June to December, the RM 10c performs well and the apparent bias is eliminated with only one QC failure out of 242 determinations. The second highest RM, 18c with an expected grade of 3.52 g/t Au also performs reasonably well with no bias and very few QC failures. In contrast, all of the low 10 A n a l y t i c a l S o l u t i o n s L t d .

grade RMs (0.3 to 1.6 g/t Au) show a low bias in the order of -5% and very high failures rates. Results are summarized in Table 3.2.2-b. Table 3.2.2-b: Summary of Reference Materials at SGS (June 2012 onwards)

RM OREAS 15f OREAS 15g OREAS 15d OREAS 18c OREAS 10c Total

Total N 94 169 236 283 242 1,024

Expected Au (g/t) Average Std. Dev. 0.334 0.016 0.527 0.023 1.559 0.042 3.520 0.110 6.600 0.160

Observed Au (g/t) % of QC Average Std. Dev. Expected Failures 0.320 0.012 95.7 13 0.509 0.017 96.6 23 1.516 0.040 97.2 38 3.483 0.073 98.9 3 6.590 0.116 99.9 1 * - Weighted Average 98.1* 78

All of the 15-series RMs are prepared from the same mafic metavolcanics source and the homogeneity of the material has been rigorously tested. It can only be assumed that SGS made changes to its fire assay procedures that resulted in a low bias post-May for gold concentrations less than about 1 g/t Au. It is noted that there were no results identified as mislabels which is an improvement relative to previous drilling campaigns.

QC Failure Actions All of the RM assay-related QC failures were investigated and followed up by Madeline Thon (MT). The ‘Actions Taken by Madeline Thon (MT)’ are reported to ASL as a table to summarize the actions taken by Detour when individual QC failures are reported. In general, no further action was taken because the results were within 10-15% of the expected value and/or in waste rock. SGS has performed assaying for Detour Gold for approximately six years and QC failure rates have ranged from a low of 1% errors (2008–2009) to a high of 20%, which prompted laboratory audits and resulted in identifying several concerns at SGS. A total of 3% of the total RMs submitted to SGS between February and May were identified as QC failures and the failure rate is within an acceptable range. PostMay 2012, the failure rate increased to 15% for RMs in the 1 g/t Au grade range which is outside an expected range for QC failures.

Quality Control on the Basis of Consecutive Failures The RM data were also reviewed to determine where there were two or more consecutive RMs where the results were biased both low or both high in the same work order. Biases of greater than +2

11 A n a l y t i c a l S o l u t i o n s L t d .

standard deviations or less than -2 standard deviations were used to identify cases that require repeats. These cases are listed in Table 3.2.3. There were a total of 41 consecutive failures at SGS. Out of these 41 cases, 16 cases were already identified as failures (outside +/-10%). The failures almost always show a low bias for the lower grade RMs, providing further evidence of a low bias at SGS.

12 A n a l y t i c a l S o l u t i o n s L t d .

TWDDH-373 TWDDH-373

Sample No. BA29010 BA29100

Table 3.2.3: List of Additional QC Failures for RMs Observed Expected Expected Certificate Lab RM Au (g/t) Au (g/t) Std. Dev. A11-13917 ActLabs GS-1H 0.887 0.972 0.041 A11-13917 ActLabs GS-3J 2.460 2.710 0.080

Date Recd. 04-01-12 04-01-12

% of Expected -8.74 -9.23

TWDDH-373 TWDDH-373 TWDDH-373

BA29130 BA29230 BA29270

A11-13917 A11-13917 A11-13917

ActLabs ActLabs ActLabs

GS-3J GS-1P5D GS-6B

2.880 1.600 6.710

2.710 1.470 6.450

0.080 0.059 0.101

04-01-12 04-01-12 04-01-12

6.27 8.84 4.03

2.13 2.20 2.57

TWDDH-377 TWDDH-377 TWDDH-377 TWDDH-377 TWDDH-377 TWDDH-377 TWDDH-377 TWDDH-377

W1261900 W1261940 W1261950 W1261960 W1261970 W1262030 W1262050 W1262060

A11-14625 A11-14625 A11-14625 A11-14625 A11-14625 A11-14625 A11-14625 A11-14625

ActLabs ActLabs ActLabs ActLabs ActLabs ActLabs ActLabs ActLabs

GS-P4A GS-3J GS-P4A GS-1H GS-1P5D GS-3J GS-1H GS-P4A

0.491 2.910 0.491 1.060 1.640 2.900 1.060 0.511

0.438 2.710 0.438 0.972 1.470 2.710 0.972 0.438

0.013 0.080 0.013 0.041 0.059 0.080 0.041 0.013

03-01-12 03-01-12 03-01-12 03-01-12 03-01-12 03-01-12 03-01-12 03-01-12

12.10 7.38 12.10 9.05 11.56 7.01 9.05 16.67

4.11 2.50 4.11 2.15 2.88 2.38 2.15 5.66

TWDDH-377 TWDDH-377

W1262100 W1262110

A11-14625 A11-14625

SGS SGS

GS-P4A GS-3J

0.503 2.910

0.438 2.710

0.013 0.080

03-01-12 03-01-12

14.84 7.38

5.04 2.50

DBKA12-0057 DBKA12-0057

D1095463 D1095503

SU20314 SU20314

SGS SGS

15g 15d

0.456 1.410

0.527 1.559

0.023 0.042

31-07-12 31-07-12

-13.47 -9.56

-3.09 -3.55

DBKA12-0007 DBKA12-0007

D1099980 D1100020

SU19016 SU19016

SGS SGS

15g 15d

0.470 1.450

0.527 1.559

0.023 0.042

04-04-12 04-04-12

-10.82 -6.99

-2.48 -2.60

TWDDH-155 TWDDH-155

D1106356 D1106396

SU20310 SU20310

SGS SGS

15g 15d

0.458 1.450

0.527 1.559

0.023 0.042

31-07-12 31-07-12

-13.09 -6.99

-3.00 -2.60

DBKA12-0046 DBKA12-0046

D1108230 D1108270

TO121490 TO121490

SGS SGS

15g 15d

0.478 1.470

0.527 1.559

0.023 0.042

16-07-12 16-07-12

-9.30 -5.71

-2.13 -2.12

DBKA12-0046 DBKA12-0046

D1108310 D1108350

TO121491 TO121491

SGS SGS

10c 18c

6.120 3.270

6.600 3.520

0.160 0.110

11-07-12 11-07-12

-7.27 -7.10

-3.00 -2.27

Hole No.

13 A n a l y t i c a l S o l u t i o n s L t d .

z-score -2.07 -3.13

DBKA12-0069 DBKA12-0069

Sample No. D1113861 D1113901

DBKA12-0044 DBKA12-0044

D1116791 D1116831

TO121677 TO121677

SGS SGS

15g 15d

0.462 1.430

0.527 1.559

0.023 0.042

20-07-12 20-07-12

-12.33 -8.27

-2.83 -3.07

DBKA12-0075 DBKA12-0075

D1117260 D1117300

TO121344 TO121344

SGS SGS

15g 15d

0.464 1.420

0.527 1.559

0.023 0.042

06-07-12 06-07-12

-11.95 -8.92

-2.74 -3.31

DBKA12-0076 DBKA12-0077

D1118585 D1118623

TO121743 TO121743

SGS SGS

15d 15g

1.420 0.448

1.559 0.527

0.042 0.023

23-07-12 23-07-12

-8.92 -14.99

-3.31 -3.43

DBKA12-0079 DBKA12-0080

D1120492 D1120503

SU20292 SU20292

SGS SGS

15g 15g

0.453 0.471

0.527 0.527

0.023 0.023

20-07-12 20-07-12

-14.04 -10.63

-3.22 -2.43

DBKA12-0116 DBKA12-0116

D1129187 D1129227

TO123532 TO123532

SGS SGS

15f 15d

0.302 1.460

0.334 1.559

0.016 0.042

16-10-12 16-10-12

-9.58 -6.35

-2.00 -2.36

TWDDH-154 TWDDH-155

D1136242 D1136264

SU21508 SU21508

SGS SGS

15f 15d

0.291 1.470

0.334 1.559

0.016 0.042

23-11-12 23-11-12

-12.87 -5.71

-2.69 -2.12

DBKA12-0130 DBKA12-0130

D1139264 D1139304

SU21211 SU21211

SGS SGS

15f 15d

0.295 1.440

0.334 1.559

0.016 0.042

12-11-12 12-11-12

-11.68 -7.63

-2.44 -2.83

Hole No.

18c 15g

Observed Au (g/t) 3.010 0.480

Expected Au (g/t) 3.520 0.527

Expected Std. Dev. 0.110 0.023

Date Recd. 25-05-12 25-05-12

% of Expected -14.49 -8.92

Certificate

Lab

RM

TO120901 TO120901

SGS SGS

14 A n a l y t i c a l S o l u t i o n s L t d .

z-score -4.64 -2.04

4.0 Laboratory Pulp Duplicates Commercial laboratories routinely assay a second aliquot of the sample pulp usually for one in ten samples. The data are used by the laboratory for their internal quality control monitoring. The data are either automatically reported to clients or can be requested. The assays for pulp duplicates provide an estimate of the reproducibility related to the uncertainties inherent in the analytical method and the homogeneity of the pulps. The precision or relative percent difference calculated for the pulp duplicates indicates whether pulverizing specifications should be changed and/or whether alternative methods, such as screened metallics for gold, should be considered. The original and duplicate assays are plotted in Figure 4.1. There were a total of 1,506 laboratory duplicate gold assays provided to ASL. Additional graphs are presented in Appendix 3. Figure 4.1: Laboratory Pulp Duplicates

15 A n a l y t i c a l S o l u t i o n s L t d .

The coefficient of variation (CV) was calculated for each sample pair using the equation:

The average CV (Table 4.1) was calculated by summing the square of the CV and dividing by the number of samples. Precision is then estimated as twice the average CV (as a percentage); this means that approximately 96% of the samples (i.e. two standard deviations) will fall within an envelope defined by plus or minus the estimated precision. Table 4.1: Precision for Laboratory Pulp Duplicate Pairs

N> 10*d.l.

Precision (2*CV%)

all samples > 10*dl 0.05 - 0.1 g/t Au 0.1 - 1 g/t Au*1

714 236 358

66.82 58.13 54.59

1 - 5 g/t Au*2 >5 g/t Au *3

75 15

52.76 50.86

Criteria

*1

- 24 samples excluded from calculations

*2

- 5 samples excluded from calculations

*3

- 1 sample excluded from calculations

Duplicate assays reported by SGS are within the expected range and similar to previous periods. Based on these data, the pulps are reasonably homogeneous with respect to gold for a deposit with free gold.

16 A n a l y t i c a l S o l u t i o n s L t d .

5.0 Preparation Duplicates Preparation duplicates are created by splitting a second cut of the crushed sample in the same way and for the same weight as the original sample. The objective is to determine if: a)

splitting procedures are applied consistently; and

b)

changes to sample preparation procedures, specifically specification for the crush size, are required.

A total of 1,564 preparation duplicates were prepared routinely by SGS. The reproducibility of 47% of these assays was within ±20% (Table 5.1 and Figure 5.1). Additional graphs are presented in Appendix 4. Figure 5.1: Comparison of Gold Assays for Preparation Duplicates

17 A n a l y t i c a l S o l u t i o n s L t d .

Table 5.1: Percentage of Preparation Duplicate Pairs Reporting Within Specific Ranges for Gold Assays Criteria

N

all samples

1,564

> 5 x d.l.

988

>5 x dl & 5 g/t Au Original

12

+5% 337 22% 138 14% 62 14% 63 14% 12 16% 1 8%

+10% 547 35% 295 30% 126 29% 140 30% 26 34% 3 25%

N = Falling Within +20% +25% 815 938 52% 60% 460 547 47% 55% 205 249 47% 57% 213 252 46% 55% 36 40 47% 52% 6 6 50% 50%

+50% 1,254 80% 782 79% 353 80% 361 78% 57 74% 11 92%

>+50% 310 20% 206 21% 86 20% 99 22% 20 26% 1 8%

The calculation of CV% for pulp duplicates (see Table 4.1), provides an estimate of the reproducibility for the sample population. It is very similar to the CV% calculated for preparation duplicates at the same grade ranges (Table 5.1). This suggests that the coarse crushing specifications and splitting procedures are acceptable and that most of the reproducibility issues persist for the finer-ground materials. Table 5.1: Precision for Preparation Duplicate Pairs

Criteria all samples > 10*dl 0.05 - 0.1 g/t Au 0.1 - 1 g/t Au*1

1 - 5 g/t Au*2 >5 g/t Au*3 *1

N> 10*d.l. 783 212 445 70

Precision (2*CV%) 70.84 61.51 52.42 49.91

12

47.61

- 36 samples excluded from calculations

*2

- 7 samples excluded from calculations

*3

- 1 sample excluded from calculations

The reproducibility is similar to the results for preparation duplicates for the Detour main deposit (Figure 5.2) and within expected ranges.

18 A n a l y t i c a l S o l u t i o n s L t d .

Figure 5.2: Summary of Reproducibility for Preparation Duplicates

19 A n a l y t i c a l S o l u t i o n s L t d .

6.0 Drill Core Duplicate Samples The second half of a drill core sample is assayed to determine: (a) the reproducibility of assays for different halves of the core, and (b)

if there is any sampling bias.

A total of 1,370 pairs were submitted, out of which there are 1,056 cases where the mean of the two values is greater than 0.025 g/t (five times detection limit) which are considered for statistical analysis. There are 529 cases where the assays for the original sample are higher than duplicate sample and 504 cases where the opposite is true (Table 6.1). Table 6.1: Summary of Gold Assays for Core Duplicates Criteria

N

all samples

1,370

> 5 x d.l.

1,056

Orig. Core > Dupl. Core 619 45% 529 50%

Orig. Core < Dupl. Core 603 44% 504 48%

Orig. Core = Dupl. Core 148 11% 23 2%

The gold assays for the original and duplicate samples are compared in Figure 6.1. Additional graphs are present in Appendix 5. Figure 6.1: Comparison of Gold Assays for Drill Core Duplicates

20 A n a l y t i c a l S o l u t i o n s L t d .

Relative Percent Difference (“RPD”) was calculated (original core assay less duplicate core assay relative to the average). The results are summarized in Table 6.2 and the graphs are in Appendix 5. Seven percent of the duplicate pairs agree within ±5%, 16% within ±10% and 32% within ±20%. Table 6.2: Summary Percentage of Core Duplicate Pairs Reporting Within Specific Ranges Criteria

N

all samples

1,370

> 5 x d.l.

1,056

>5 x dl to 0.1 g/t Au Original 0.1 to 1 g/t Au Original 1 to 5 g/t Au Original >5 g/t Au Original

560 418 71 7

+5% 202 15% 77 7% 45 8% 24 6% 6 8% 2 29%

+10% 311 23% 167 16% 95 17% 60 14% 10 14% 2 29%

N = Falling Within +20% +25% 532 603 39% 44% 334 395 32% 37% 199 240 36% 43% 114 134 27% 32% 17 17 24% 24% 4 4 57% 57%

+50% 901 66% 650 62% 383 68% 233 56% 29 41% 5 71%

>+50% 469 34% 406 38% 177 32% 185 44% 42 59% 2 29%

There were 39 cases where the differences between drill core duplicates were greater than ±100% and average assays were greater than 0.5 g/t Au (Appendix 6). There is no bias evident between original and duplicate halves of the drill core. The low percentage of agreement between the two halves of the core is expected based on review of reproducibility for preparation duplicates, the range of gold assays for samples with the same number of VG specks and other measurements, i.e. the evidence for the presence of free gold particles. It is therefore assumed that there has been no bias introduced by the preferential submission of the more mineralized half of the core for assay. These variations are typical of core duplicates for gold projects.

21 A n a l y t i c a l S o l u t i o n s L t d .

7.0 Screen Metallic Assays Screen Metallics (“FA-MET”) samples were selected on the basis of Visible Gold (“VG”) or because the original Fire Assay reported > 5 g/t. As discussed in a previous memorandum, it is important to discriminate between samples selected for FA-MET on the basis of VG versus the grade of the preliminary 50 gm fire assay. The selection of samples on the basis of the 50 gm fire assay for repeat FA-MET produces a severe selection bias that is exacerbated by preparing a second 500 g pulp from the reject. A total of 66 samples were selected on the basis of VG. The data are summarized in Table 7.1 and plotted in Figure 7.1. There is good correspondence between results and no evidence of bias between methods. Figure 7.1: Comparison of Gold by Fire Assay and Screen Metallics (selected on the basis of VG)

22 A n a l y t i c a l S o l u t i o n s L t d .

Table 7.1: Comparison of Gold by Fire Assay and Screen Metallics (selected on the basis of VG) Criteria

N

all samples

66

>1 g/t Au (SF)

60

1 to 5 g/t Au (SF)

10

5 to 10 g/t Au (SF)

10*

>10 g/t Au (SF)

40

10 to 25 g/t Au (SF)

13

>25 g/t Au (SF)

27

Screen Fire > Fire Assay 33 50% 30 50% 6 60% 3 30% 21 53% 7 54% 14 52%

Screen Fire < Fire Assay 33 50% 30 50% 4 40% 7 70% 19 48% 6 46% 13 48%

* Low number of samples significantly impacts comparison

Additionally, a total of 489 samples were selected on the basis of the original fire assay Au reporting greater than 5 g/t and assayed for gold by Screen Metallics (FA-MET). The data are summarized in Table 7.2 and plotted in Figure 7.2. Table 7.2: Comparison of Gold by Fire Assay and Screen Metallics (selected on the basis of Original Fire Assay Au >5 g/t) Criteria

N

all samples

489

>1 g/t Au (SF)

485

1 to 5 g/t Au (SF)

79*

5 to 10 g/t Au (SF)

230

>10 g/t Au (SF)

176

10 to 25 g/t Au (SF)

134

>25 g/t Au (SF)

42

Screen Fire > Fire Assay 214 44% 213 44% 0 0% 104 45% 109 62% 81 60% 28 67%

Screen Fire < Fire Assay 275 56% 272 56% 79 100% 126 55% 67 38% 53 40% 14 33%

*Samples selected for Screen Metallics are supposed to have Fire Assay 50 gm assays greater than 5 g/t Au. This group of samples does not qualify and the consistently low Screen Metallics vs. Fire Assay is not explained. 23 A n a l y t i c a l S o l u t i o n s L t d .

Figure 7.2: Comparison of Gold by Fire Assay and Screen Metallics (selected on the basis of Original Fire Assay Au >5 g/t)

The subset of samples selected on the basis of original 50 g fire assay determinations agree reasonably well with the FA-MET re-analyses for the current period. For the grade ranges greater than 10 g/t Au, the FA-MET assays are more likely to be higher than the 50 gm fire assays for about 60% of the samples tested. In the grade range 5 to 10 g/t Au, which includes 230 samples there are nearly an equal number of cases with FA-MET assays greater than 50 gm fire assays, and vice versa. This pattern has been recognized previously and is ascribed to selection bias. There is no evidence that the assays methods are biased relative to one another.

24 A n a l y t i c a l S o l u t i o n s L t d .

8.0 Check Assays at Secondary Laboratory Check assays are recommended where the same pulp that was assayed originally is submitted to a different laboratory for the same analytical procedures primarily to augment the assessment of bias based on the RMs and in-house control samples submitted to the original laboratory. Reference materials are also inserted with samples submitted to the secondary laboratory to measure whether the secondary laboratory is potentially biased. The check assay program in December-January was also used to assess whether the new SGS Cochrane laboratory was performing similarly to SGS Don Mills.

8.1

Check Assays done on Pulp Samples

A total of 205 sample pulps (not including QC samples) (~1% of the samples) were submitted to SGS Cochrane for check assays (original samples were assayed at SGS Don Mills) for the period January to December 2012. A total of six RMs and five blanks were inserted with the samples for check assays sent to SGS Cochrane. The results were plotted (Figure 8.1.1) and summarized in Table 8.1.1. Quality control failures and mislabels are excluded from the graphs and calculations in these tables. All five blanks reported below detection limit ( 5 x dl (SGS)

187

>5 x dl & 1 g/t Au SGS

72

1 to 5 g/t Au SGS

51

>5 g/t Au SGS

21

SGS-DM > SGS-C 124 60% 118 63% 74 64% 44 61% 31 61% 13 62%

SGS-DM < SGS-C 77 38% 66 35% 38 33% 28 39% 20 39% 8 38%

SGS-DM = SGS-C 4 2% 3 2% 3 3%

The average Relative Percent Difference (relative to the mean of the two laboratory results) was 4.84%, indicating that SGS Don Mills assays are biased high by 4.84% when compared to the SGS Cochrane assays on the suite of samples selected for check assays. It should also be noted that SGS Cochrane reported on average 5% low on the reference materials included with samples suggesting that the two sets of assays are comparable. SGS Cochrane had a series of issues on start-up which appear to have persisted for the check assay program. There were four samples (representing 2% of the samples submitted for check assays) that had assays reported that were different by more than 100%. This is expected based on comparison of results within the same laboratory and also for free gold-bearing deposits. The reproducibility of gold assays for check assay samples with Au assays greater than five times the detection limit were compared to similar data for laboratory pulp duplicates and plotted (Figure 8.1.3). Figure 8.1.3 shows that on average the reproducibility of the pulps assayed at the same laboratory (SGS) is not as good as when the pulp is resubmitted to a second laboratory (SGS Cochrane). This is counterintuitive since assaying of routine pulp duplicates is generally done at the same time (same furnace, same assayer) as the original assay and therefore has a better chance of repeating well compared to when assays are compared from different laboratories. 27 A n a l y t i c a l S o l u t i o n s L t d .

Figure 8.1.3: Comparison of Check Assays and Laboratory Pulp Duplicates

8.2

Check Assays done on Core Samples

A batch of 200 core samples were selected and sampled as additional half-core duplicates and sent to SGS Cochrane for check assays (original samples were assayed at SGS Don Mills). A total of six RMs and five blanks were inserted with the samples for check assays sent to SGS Cochrane. The results were plotted and are shown in Figure 8.2.1 and summarized in Table 8.2.1. There were no quality control failures or mislabels. Three out of five blanks reported below 10 times the detection limit ( 5 x dl (SGS)

183

>5 x dl & 1 g/t Au SGS

69

1 to 5 g/t Au SGS

50

>5 g/t Au SGS

19

SGS-DM > SGS-C 101 50% 97 53% 56 49% 41 59% 30 60% 11 58%

SGS-DM < SGS-C 98 49% 86 47% 58 51% 28 41% 20 40% 8 42%

SGS-DM = SGS-C 1 1%

It should also be noted that SGS Cochrane reported on average 2% low on the reference materials included with samples. There were 12 samples (representing 6% of the samples submitted for check assays) that had assays reported that were different by more than 100%. This is expected based on comparison of results within the same laboratory and also for free gold-bearing deposits.

31 A n a l y t i c a l S o l u t i o n s L t d .

9.0 Laboratory Audit SGS Don Mills is a well-recognized ISO-accredited laboratory. The laboratory is being shut down as of April 2013 and future gold assaying will be done at the SGS facility in Peterborough. An audit of the new facility is warranted if Detour plans to use SGS for exploration assays. SGS Cochrane was established mid-2012 to support the Detour Gold mine operations. Two visits were made by Lynda Bloom, in July and January, 2013 and reports have been filed for this period where SGS Cochrane assayed mine samples. With the exception of the check assay program, no drill core has been assayed at SGS Cochrane.

32 A n a l y t i c a l S o l u t i o n s L t d .

10.0 Conclusions There is no evidence of systematic gold contamination based on the blanks that were inserted with samples. Blanks were submitted a total of 1,362 times with samples. There was a single quality control failure based on blanks (