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Fort Knox Mine Reclamation and Closure Plan - Alaska Department PDF

143 Pages·2006·38.01 MB·English
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Preview Fort Knox Mine Reclamation and Closure Plan - Alaska Department

RECLAMATION & CLOSURE PLAN prepared by Fairbanks Gold Mining, Inc. (a subsidiary of Kinross Gold Corporation) PO Box 73726 Fairbanks, Alaska 99707-3726 (907) 488-4653 June 19, 2006 FORT KNOX MINE RECLAMATION AND CLOSURE PLAN Submitted to: Alaska Department of Natural Resources Division of Mining, Land and Water 3700 Airport Way Fairbanks, Alaska 99709 Alaska Department of Environmental Conservation Division of Air and Water Quality 610 University Avenue Fairbanks, Alaska 99709-3643 and Department of the Army U.S. Army Engineer District, Alaska P.O. Box 6898 Elmendorf AFB, Alaska 99506-6898 Submitted by: Fairbanks Gold Mining, Inc. A Subsidiary of Kinross Gold Corporation P.O. Box 73726 Fairbanks, Alaska 99707-3726 June 19, 2006 Fort Knox Reclamation & Closure Plan June 19, 2006 TABLE OF CONTENTS LIST OF FIGURES vii LIST OF TABLES viii APPENDICES ix LIST OF ABBREVIATIONS x TSF – Tailing Storage Facility x 1.0 INTRODUCTION 1 1.1 Purpose 1 1.2 Applicant Information 2 Fairbanks Gold Mining, Inc. Officer Completing Application 2 Designated Contact Person 2 Kinross Gold Corp. Information 2 Alaska Registered Agent 3 1.3 Location and Land Status 3 1.4 History of Fort Knox Mine 7 2.0 PROJECT DESCRIPTION 8 2.1 Existing Facilities and Conditions 8 Mill Facilities 8 Tailing Storage Facility 9 Decant Water 10 Seepage Water 11 Water Reservoir 12 Walter Creek Heap Leach Facility 12 2.2 General Environmental Information 14 Geology 15 Climate 15 Vegetation, Soils and Permafrost 15 ii Fort Knox Reclamation & Closure Plan June 19, 2006 Surface Water 16 Groundwater 17 Alluvium 17 Bedrock 18 Background Water Chemistry 18 3.0 FORT KNOX WETLANDS 19 3.1 Jurisdictional Wetland Survey 19 3.2 Department of the Army Section 404 Permit 20 3.3 Fish Creek Valley Developed Wetlands Delineation 20 3.4 Developed Wetlands Functional Analysis 23 3.5 Heap Leach Wetland Impacts 24 3.6 Fishery Development and Enhancement 28 4.0 SURFACE DISTURBANCE AND LAND USE 28 4.1 Surface Disturbance 28 Placer and Other Mining Disturbances as of August 1992 28 Reclamation of Pre-Mining Disturbances 29 Fort Knox Mine Disturbance 29 4.2 Land Use 29 Land Use Prior to Fort Knox 29 Land Use During Fort Knox Operation 30 Post-Mining Land Uses 30 5.0 RECLAMATION PRACTICES 31 5.1 Schedule of Reclamation Activities 32 Reclamation Schedule 32 Reclamation of Construction Sites 34 Concurrent Reclamation 34 Final Reclamation 36 Temporary Closure 36 iii Fort Knox Reclamation & Closure Plan June 19, 2006 5.2 General Reclamation Procedures 37 Earthwork 37 Control of Sedimentation 37 Growth Media 37 Seedbed Preparation 38 Fertilizer and Fertilization 39 Seed and Seeding 39 Revegetation Timing 40 Fort Knox Vegetative Restoration Studies 40 Revegetation Cover Criteria 40 5.3 Post-Mining and Post-Reclamation Topography 41 Drainage 41 Figure 5.2 Pre-development Ground Conditions at the Fort Knox Mine 42 Pit Slope Stability 45 Acid Rock Drainage (ARD) Potential 45 5.4 Public Access 48 6.0 FACILITY SPECIFIC RECLAMATION AND CLOSURE 48 6.1 Water Management 49 Receiving Water Beneficial Use 49 Mine Site Surface Water 49 Summary Water Management Strategy 50 6.2 Tailing Storage Facility Reclamation & Closure 51 Closure Sequence 53 Tailings Surface 54 Tailing Spillway 56 Wetland Treatment System 56 Tailings Embankment 58 6.3 Seepage Interception System 58 6.4 Pit Lake 59 6.5 Heap Leach Closure 60 Heap Leach Closure Procedures And Schedule 61 Residual Leaching 61 iv Fort Knox Reclamation & Closure Plan June 19, 2006 Solution Recirculation/Rinsing 61 Release Of Draindown To The Tailing Impoundment 62 Release of minor long-term seepage to the tailing impoundment 62 Regrading and cover 62 6.6 Water Supply Reservoir, Solo Creek Causeway and Gil Causeway 62 6.7 Roads 64 6.8 Open Pit / Melba Monte Cristo Causeway 64 6.9 Waste Rock Dumps 65 6.10 Building and Equipment Sites 66 6.11 Wells and Well Closure 67 6.12 Miscellaneous Sites 67 Fence Removal 67 Electrical Power Facilities 67 Material Borrow Areas 68 7.0 MONITORING 69 7.1 Tailing Impoundment 69 Water Level Monitoring 73 Inspection of Surface Stabilization 73 7.2 Heap Leach 73 7.3 Long-Term Maintenance and Monitoring 76 Long-term Monitoring 76 Long-term Maintenance 76 8.0 APPLICANT STATEMENT OF RESPONSIBILITY 77 9.0 ESTIMATE OF RECLAMATION AND CLOSURE COSTS 78 9.1 Reclamation Cost Estimates and Financial Assurance Adjustment 78 v Fort Knox Reclamation & Closure Plan June 19, 2006 9.2 Agreement for Funding Post-Reclamation Obligations 79 10.0 ACKNOWLEDGEMENTS 80 11.0 REFERENCES 81 vi Fort Knox Reclamation & Closure Plan June 19, 2006 LIST OF FIGURES Figure 1.0 Fort Knox Mine Site Location Map 4 Figure 1.1 Fort Knox Mine Site General Arrangement 5 Figure 1.2 Upland/Millsite Permit Areas 6 Figure 3.0 Summary of Wetland Functional Scores 25 Figure 3.1 Comparison of Functional Scores Subtotals and Total 26 Figure 3.2 Heap Leach and Jurisdictional Wetlands 27 Figure 5.0 Schedule of Reclamation Activities 33 Figure 5.1 Fort Knox Growth Media Stockpiles 35 Figure 5.2 Pre-mining Topography 42 Figure 5.3 Post-Mining Topography 43 Figure 5.4 Post-Reclamation Topography 44 Figure 5.5 Cross-Section of Final Pit 46 Figure 5.6 Plan View of Final Pit 47 Figure 6.1 ADEC Solid Waste Disposal Permit Boundary 52 Figure 6.2 Plan View of Tailing Reclamation and Revegetation Map 55 Figure 6.3 Plan View of Wetland Treatment System 57 Figure 6.4 Fort Knox Water Reservoir Recreation Area 63 Figure 6.5 Fort Knox Groundwater Well Location Map 68 Figure 7.0 Water Monitoring Locations 70 vii Fort Knox Reclamation & Closure Plan June 19, 2006 LIST OF TABLES Table 2.0 Comparison of Decant Pond and Seepage Water 12 Table 3.0 Jurisdictional Wetlands Summary 1992 19 Table 3.1 Jurisdictional Wetlands Breakdown 1992 20 Table 3.2 Mitigation Requirements of the TSF Required by 404 Permit 20 Table 3.3 Comparison of Acres Created/Enhanced/404 Mitigation 22 Table 3.4 Summary of Wetland and Open Water Acres to be Created 22 Table 4.0 Areas and Acreages of Disturbance 30 Table 5.1 Estimated Growth Media Volumes 38 Table 5.2 Seed Mix 39 Table 6.0 Predicted Pit Lake Quality at Full Recovery 59 Table 6.1 List of Fort Knox Buildings at Completion of Mining 66 Table 7.0 Summary of Closure Monitoring 70 Table 7.1 Summary of Monthly and Quarterly Analyte List 73 Table 7.2 Summary of Monitoring Requirements for Heap Leach 74 Table 7.3 Analytical Profile II—Groundwater Inorganic Parameters 75 Table 9.0 Reclamation & Closure Cost Estimate 77 viii Fort Knox Reclamation & Closure Plan June 19, 2006 APPENDICES APPENDIX A Agreement for Funding Post-Reclamation Obligations APPENDIX B Surface and Mineral Land Descriptions and Claims Map APPENDIX C National Park Service, U.S. Department of the Interior, Fire Monitoring Handbook Point- Intercept Method APPENDIX D Gil Causeway Reclamation Plan ix

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Jun 19, 2006 Fairbanks Gold Mining, Inc. Officer Completing Application. 2 .. A series of six groundwater pump-back wells, immediately down The data indicate that the seal and drainage systems are . storage embankment is expected to be similar to the mechanical .. and sampling data (Ott and
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