Environmental Assessment for Golden Sunlight Mining, Inc., Application
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Digitized by the Internet Archive in 2013 http://archive.org/details/environmentalass31mont 3^^-^ Rn7rMAM PlIDIir i.noAow '"'1195? BOIlim PUBLIC LIBRARY EN ^V I R O NIM EN T ^^VX^ ^^^SSESSiVlElSTT for Golden Sunlight Mining, Inc. Application for Anendcent State Operating Permit No. 00065 and Federal Plan of Operations Stage IV and V Mining Operating and Reclamation Plan prepared by Montana Department of State Lands and U.S. Department of Interior Bureau of Land Management pursuant to the Montana Environmental Polict Act and the National Environmental Policy Act May 30, 1990 3 0864 1006 3080 8 . TABLE OF CONTENTS CHAPTER I - INTRODUCTION 1 A. Purpose and Need 1 B. Permitting History 5 C. Summ£Lry of Proposed Amendment 5 D. Location and Land OuTiership 11 E. Environmental Analysis History 11 F. Related Actions 12 G. Agency Responsibilities 12 1. Department of State Lands 12 2. Bureau of Land Management 13 3. Other State Agencies 13 a. State Historic Preservation Office 13 b. Department of Health and Environmental Sciences 14 i. Air Quality Bureau 14 ii. Water Quality Bureau (W'QB) 14 c. Department of Natural Resources and Conservation (DNRC) 14 d. Hard-Rock Mining Impact Board 14 CHAPTER 11 - EXISTING ENVIRONMENT 13 A. Geology 13 B. Soils 14 1. Soil Developmental Setting 14 a. Parent Material/ Geology 14 b. Other Soil Forming Influences 15 2. Existing Soils 15 a. Proposed Tailing Impoundment II Area ... 15 b. North Waste Rock Dump Area 16 c. West and South Waste Rock Dump Areas . 20 C. Water Resources 20 1. Surface Water 20 2. Groundwater 23 a. Bedrock Aquifer 24 b. Bozeman Group Aquifer 24 c. Quaternary .Aquifer 28 d. .Jefferson Valley Aquifer 28 3. Water Rights 29 D. Vegetation 29 1 Plant Community Development 29 2. Existing Plant Communities 30 a. Proposed Tailing Impoundment II Area ... 30 b. North Waste Rock Dump Area 34 c. West and South Waste Rock Dump Aresis . 34 3. Productivity 34 a. Range Condition/Productivity/ Stocking Rate 34 b. Utilization by Livestock /Wildlife 34 .' 4. Noxious Weeds . 38 5. Species Listing 38 E. Wildlife 38 F. I^nd Use 39 G. Air Quality and Climate 40 H. Transportation 41 I. Noise 42 J. Socioeconomic and Human Environment 42 1. Jefferson County 42 a. Employment and Income 42 b. Government Finances 43 c. Social Life 44 d. Community Services 44 e. Housing 44 2. Golden Sunlight Mining, Inc 44 a. Employment and Income 44 b. Government Finances 45 c. Social Life 46 d. Community Services 46 K. Cultural Resources 47 1. Prehistoric Activities 47 2. Historic Activities 47 L. Aesthetics 47 M. Energy 48 CHAPTER III - THE COMPANY'S PROPOSED ACTION 43 A. General Permit History and Explanation of Operations 43 B. Present Operating and Reclamation Plan 45 1. Operating Plan 46 2. Monitoring Plan 47 3. Reclaimation Plan 48 a. Tailing Impoundment I 48 b. Waste Rock Dumps 49 c. Pit Reclamation 49 d. Miscellaneous Facilities 50 C. Proposed Plan of Operations and Reclamation Plan ... 50 1. Operating Plan 50 2. Reclamation Plan 52 a. Waste Rock Dumps 52 b. Tailing Impoundment II 52 i. Temporary Stabilization 52 ii. Concurrent Reclamation 52 ill. Final Closure 53 iv. Monitoring and Remedial Action .... 54 c. Pit Reclamation 55 d. Miscellaneous Facilities 55 D. Consequences of the Company's Proposed Plan .... 55 1 . Geology 55 a. Waste Rock Dump Stability 56 b. Tailing Impoundment II Stability 56 c. Pit Stability 58 d. Waste Rock Characterization 58 i. Acid Potential Studies 59 (a) Acidity 60 Cb) Neutralization 60 (c) Weathering 61 (d) Mineral Size and Morpholep Examination 62 ii. Toxic metal Concentrations 62 e. Tailing Characterization 63 i. Acid Pioduction Potential 63 ii. Other Tailings Characteristics .... 64 f. Summary 65 i. Structure Stability 65 ii. Acid Producing Potential 65 2. Soils 66 a. Soil Salvage 66 b. Revegetation Trials 69 d. Waste Rock Dumps Soil Salvage Pla- s .... 72 3. Water Resources 73 a. Pit Water 73 b. Waste Rock Dumps Seepage 75 c. Tailing Impoundment Seepage 76 i. Impoundment II 76 ii. Impoundment I 78 iii. Total Impoundment Seepage 81 d. Water Rights 82 4. Vegetation 82 a. Plant Community Diversity 82 b. Plant Species Diversity 82 c. Plant Forage and Shelter for Livestock and Wydhfe 85 d. Revegetation Potential b5 e. Erosion Potential 86 i. Erosion During Operations 86 ii. Post-mine Erosion Potential 86 f . Aesthetic Impacts 88 5. WOdUfe 89 6. Land Use 90 7. .Air Quality and Climate 92 a. Direct 92 b. Indirect 92 c. Total 92 8. Transportation 93 9. Noise 93 10. Socioeconomics 93 11. Cultural Resources 94 12. Aesthetics 94 CILAPTER IV - CONTPANY'S PROPOSED PLAN WITH SUPPLEMENT.AL COMMITMENTS 91 A. Introduction and Description of the Issues 91 B. Reclamation Plan 92 1. Waste Rock Dumps 92 a. Slope Reduction 93 b. Waste Rock Cap 93 c. Liming 94 d. Soil Placement 94 e. Revegetation 95 f . Seepage/Water Treatment 95 2. Tailing Impoundments 95 a. Reclamation Objectives 95 b. Embankment Reclamation Plan 96 c. Impoundment Surface Reclamation Plan ... 96 d. Seepage/ Water Treatment 97 3. Pit Reclamation 97 a. Reclamation Plan 97 b. Seepage /Water Treatment 98 4. Miscellaneous Facilities Reclamation 99 C. Consequences of the Company's Proposed Plan With Supplemental Commitments 99 1. Waste Rock Dumps Reclamation 99 a. Slope reduction 99 b. Waste Rock Cap 102 c. Liming 103 d. Soil Placement 103 2. Tailing Impoundments 108 a. Embankment Reclamation Plan 108 b. Impoundment Surface Reclamation Plan . 109 i. Surface Preparation and Dewatering 109 ii. Waste Rock Cap 109 iii. Liming 110 iv. Soil Placement 110 V. Revegetation 110 c. Seepage/ Water Treatment 110 3. Pit Reclamation 117 a. Reclamation Plan 117 b. Seepage/Water Treatment ^ 117 4. Miscellaneous Facilities 121 CHAPTER V - COI^TPANY'S PROPOSED PL.A.N WITH SUPPLEMENTAL COMMITMENTS AND ADDI- TIONAL MODIFICATIONS (PREFERRED AL- TERNATIVE) 119 A. Introduction and Description of Issues 119 B. Reclamation Plan 119 1. Waste Rock Dumps 119 a. Slope Reduction 119 b. Rock Capping 120 c. Liming 120 d. Soil Placement 120 e. Revegetation 120 f . Seepage/Water Treatment 120 2. Tailing Impoundments 120 a. Reclamation Objectives 120 b. Embankment Reclamation 121 c. Impoundment Surface 121 d. Seepage /Water Treatment 121 3. Pit Reclamation 122 a. Reclamation Plan 122 b. Seepage /Water Treatment 122 4. Miscellaneous Facilities 122 5. Additional Measures for Consideration 122 C. Consequences of Additional Mitigating Measures . 123 1. Waste Rock Dump Reclamation 123 a. Slope Reduction 123 b. Waste Rock Cap 123 c. Liming 124 d. Soil Placement 124 e. Revegetation 124 f . Seepage /Water Treatment 124 2. Tailing Impoundinents 124 a. Embankment Reclamation 124 b. Impoundment Surface 124 c. Seepage/Water Treatment 125 3. Pit Reclamation 125 a. Reclamation Plan 125 b. Seepage/Water Treatment 125 4. Miscellaneous Facilities 125 5. Additional Measures for Consideration 125 CR.A.PTER VI - DENLAJ. ALTERNATIVE 129 A. Introduction \nd Description of the Issues 129 B. Reclamation Plan 129 1. Waste Rock Dumps 129 a. Slope Reduction 129 b. Waste Rock Cap 129 c. Liming 129 d. Soil Placement 130 e. Revegetation 130 f. Seepage/Water Treatment 130 2. Tailing Impoundment 130 a. Reclamation Objectives 130 b. Embankment Reclamation 130 c. Impoundment Surface 130 d. Seepage/Water Treatment 130 3. Pit Reclamation 131 a. Reclamation Plan 131 b, Seepage/Water Treatment 131 4. Miscellaneous Facilities 131 5. Aesthetics 131 B. Consequences of Application Denial 131 1. Waste Rock Dump Reclamation 131 a. Slope Reduction 131 b. Waste Rock Cap 132 c. Liming 132 d. Soil Placement 132 e. Revegetation 132 f . Seepage/Water Treatment 132 2. Tailing Impoundment 132 a. Embankment Reclamation 132 b. Impoundment Surface 132 c. Seepage/Water Treatment 133 3. Pit Reclamation 133 a. Reclamation Plan 133 b. Seepage/Water Treatment 133 4. Miscellaneous Facilities 133 5. Socioeconomic and Human Environment 133 a. Employment and Income 133 b. Government Finances 133 C. Social Life 134 d. Community Services 134 e. Survey of Local Officials 134 CHAPTER VII - RELATED ACTIONS AND CUMULATIVE IMPACTS 137 A. Related Actions 137 B. Cumulative Impacts 137 1. Company's Proposed Plan 137 a. Soils 137 b. Water Resources 137 C. Socioeconomic 138 d. Aesthetics 138 2. Company's Proposed Plan with Supplemental Commitment 138 a. Soils 138 b. "Water Resources 138 c. Socioeconomic 138 d. Aesthetics 138 3. Company's Plan with Supplemental Commitments and Additional Modifications 139 a. Soil 139 b. "Water Resources 139 c. Socioeconomic 139 d. Aesthetics 139 4. Denial Alternative 139 a. Soils 139 b. Water Resources 139 c. Socioeconomic 140 d. Aesthetics 140 CHAPTER VIII - SUMMARY AND CONCLUSIONS 141 A. Reclamation of Reactive Wastes 141 1. Tailings Reclamation 141 2. Waste Rock Dump Reclaimation 141 3. Acidic Leachate Treatment 142 B. Impact Summaries and Permit Conditions 142 CHAPTER IX - CONSULTATION AND COORDINATION 145 A. Public Involvement 145 B. Consultation and Coordination 145 C. Distribution and Review of this EA 145 D. E,^ Preparers 146 CR^PTER X - GOLDEN SUNLIGHT RESPONSES TO PUBLIC COMMENT 149 CHAPTER XI - REFERENCES 171 APPENDIX A - DOCUMENTATION OF EXISTING AND PROPOSED PL.^NS AND SUPPLEMENT COmilTMENTS FROM GOLDEN SUNLIGHT MINES WHICH ARE NOT CONTAINED IN THE PERMIT APPLICATION 177 APPENDIX B. MASS B.AU^NCE MODEL DESCRIPTION 201 APPENDIX C 209 I. INTRODUCTION 211 II. INVESTIGATION PROCESS 211 III. HYDROGEOLOGIC CONDITIONS 212 IV. WATER CHOnSTRY 213 A. Cyanide 213 B. Nitrate 214 V. CONCLUSIONS 216 VI. RECOMMENDATIONS 217 APPENDIX D. GOLDEN SUNLIGHT MINE SOIL LOSS C.AiCULATIONS 219 APPENDIX E SOIL S.ALVAGE EVALUATION ON ACRES DISTURBED BY 3H:1V SLOPE REDUCTION OF WASTE ROCK DUMPS 227 APPENDIX F 229 INTRODUCTION 230 INVESTIGATION PROCESS 230 RESULTS 231 WATER CHEMISTRY 231 SOIL NITRATE 231 Nitrogen Isotope 232 DISCUSSION 232 CONCLUSIONS 233 REFERENCES CITED 234 LIST OF FIGURES Figure 1 .