Slide 1: Reclamation: The Stibnite Gold Project
RECLAMATION THE STIBNITE GOLD PROJECT Valley County, Idaho Q3 2020
Slide 2: Webinar Agenda
WEBINAR AGENDA • Introduction • Reclamation & Closure Plan; Goals, Objectives & Strategies • General Reclamation Practices • Specific Reclamation & Closure Practices • Reclamation Summary
Slide 3: Stibnite Gold Project
STIBNITE GOLD PROJECT Coeur d’Alene Stibnite Gold Project Midas Gold Au-Sb IDAHO 3
Slide 4: Historic Stibnite Mining District
1890s The Thunder Mountain gold rush brings mining to the area 1900-1930 HISTORIC STIBNITE The town of Stibnite is established 1938 Mining at Yellow Pine pit stops 1941-1950 MINING salmon migration upstream The town of Stibnite booms when antimony & tungsten were declared critical & strategic minera
Slide 5: Historic Legacy
YELLOW PINE PIT HISTORIC The East Fork of the South Fork dumps into a legacy mine pit. Currently, ~80 feet of sediment has collected at the bottom LEGACY FISH PASSAGE Fish migration is TAILINGS blocked by 10.5 million tons of legacy spent ore and the Yellow unlined tailings interact with the water t
Slide 6: Reclamation & Closure Plan
RECLAMATION & Closure Plan Goals, Objectives & Strategies
Slide 7: Goals, Objectives & Strategies
GOALS, OBJECTIVES & STRATEGIES • Concurrent reclamation and restoration activities • Stabilize all mine facilities • Control storm and contact water • Restore SGP areas to self-sustaining productive use • Protect the public, wildlife and environment during construction, operations, site closure and
Slide 8: Restoration: Upfront and Concurrent
RESTORATION: Upfront and Concurrent Period Construction Operations Closure ACTIVITY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 EFSFSR Diversion (tunnel) 2 On-Site Mine Remove spent ore in Meadow Creek valley 2 Features/Activities Legacy material reprocessing 4 Remove legacy development rock
Slide 9: Strategy
STRATEGY • Includes use of Adaptive Management • Construction • construction oversight, management, monitoring and documentation • Post-Construction • Use construction monitoring and documentation to: • Confirm or modify pre-construction design and approaches • Prepare completion reports • Modify (i
Slide 10: General Reclamation Practices
GENERAL RECLAMATION Practices
Slide 11: Soils Survey & Salvage
SOILS SURVEY & SALVAGE Tetra Tech 2017 STATSGO Identifies 9 Official Soil Series Tt IDed 6 SMU: 3 suitable and 3 unsuitable • Suitable: SMU fOD (stream channels); fTH (wetlands); and mTC (uplands) • Unsuitable: S45+ (> 45% slopes); sTC (excessive rock); and AoD (prev. disturbed/reclaimed) TOTAL GM/S
Slide 12: RCP Soil Use: TSF Replacement Depths
RCP SOIL USE PROPOSED GM/SBM TSF REPLACEMENT DEPTHS
Slide 13: RCP Soil Use: DRSF & Upland Replacement Depths
RCP SOIL USE PROPOSED GM/SBM DRSF & UPLAND REPLACEMENT DEPTHS
Slide 14: Soil Mass Balance
SOIL MASS BALANCE • GM/SBM BALANCE TOTAL GM/SBM Salvaged = 1,884,000 BCY TOTAL GM/SBM Replaced = 1,918,000 BCY Deficit = 34,000 BCY (1.8%) • GM/SBM STOCKPILES = 9 • GM/SBM ‘LIVE HANDLED’ = 150,000 BCY • OPTIONS TO ADDRESS GM DEFICIT IN ADDITION TO GENERATING COMPOST • Salvage cover from previously r
Slide 15: Composting
COMPOSTING OPPORTUNITIES TO BUILD SOILS COMPOSTING PROGRAM FOCUSED ON ADDING VOLUME AND IMPROVING GM QUALITY Improve GM quality with 10 tons per acre of compost Blend compost into GM to add volume. EVALUATE USE OF MATERIALS FROM PREVIOUSLY DISTURBED AREAS THAT CAN BECOME GM WITH AMENDMENT. On-site F
Slide 16: Planting Prescriptions
PLANTING PERSCRIPTIONS Establish self-sustaining grassland, shrub, and treed communities of “native” species VEGETATION TYPES Upland General Sites Upland Cool Sites Wetlands and Stream UPLAND REVEGETATION CLASSES Cool Aspect Grasslands General Grasslands Trees and Shrubs Parkland Trees and Shrubs Sh
Slide 17: Reclamation Specific Closure Practices
RECLAMATION Specific Closure Practices
Slide 18: Facilities Specific Closure Practices
FACILITIES SPECIFIC CLOSURE PRACTICES • Tailing Storage Facility • Hangar Flats DRSF • Backfilled Yellow Pine Pit • Fiddle DRSF • West End Pit • Burntlog Route and Thunder Mountain Roads • Fish Passage Tunnel • Exploration Related Sites • Underground Exploration • Plant Site and Worker Housing Facil
Slide 19: Tailing Storage Facility (TSF)
TAILING STORAE FACILITY (TSF) Regrade Hangar Flats DRSF Surface water controls on DRSF Cover TSF with two feet of Cap Material Cover TSF and Hangar Flats DRSF with one foot of GM Implement stream and wetland restoration
Slide 20: Stream Reclamation | Stream Restoration
STREAM RECLAMATION | STREAM RESTORATION —_ iio ape Reclamation: stable, static, i= Restoration: naturally dynamic, © little to no change; may not | Sean ae mimics mimic natural conditions Sr nditions
Slide 21: Stream design to allow migration, avulsion, scour, deposition
Stream design to allow migration, avulsion, scour, deposition
Slide 22: (09 SVGIIN ens a0 fone
0 (09 SVGIIN ens a0 fone GLOW YoReYy - ISI - 49819 MOpeaW, uBiseq }deou09 uoHRIO\sey PUENAM Puy Weas yalord plop auqns
Slide 23: Yellow Pine Pit
YELLOW PINE PIT Surface Controlled by EFSFSR channel and highwalls Mine operations will backfill to near final grade Highwalls remain in some areas Public access road Mine access road Cover with one foot of GM Implement stream and wetland restoration
Slide 24: Stream design to allow migration, avulsion, scour, deposition
Stream design to allow migration, avulsion, scour, deposition
Slide 25: Vicinity Map
VICINITY MAP. i. ia NOTES AND ASSUMPTIONS: ‘L_MINE CLOSURE GROUND SURFACE CONTOUR INTERVAL: 25' MAJORS, 5° MINORS. ') 2. FINAL GRADE OF MINE CLOSURE GROUND SURFACE INCLUDING THE YELLOW PINE PIT GRADING IS CONSIDERED PRELIMINARY AND WILL CHANGE IN FUTURE DESIGN PHASES AS THE YELLOW PINE PIT, WETLANDS
Slide 26: Yellow Pine Pit - Today
YELLOW PINE PIT - TODAY Upstream fish passage blocked since 1938 26
Slide 27: Yellow Pine Pit - Restored
YELLOW PINE PIT - RESTORED Permanently restore fish passage allows access to upstream restored/enhanced spawning and rearing habitat 27
Slide 28: Power Transmission Line
POWER TRANSMISSION LINE Post Construction Reclamation Construction Access Roads Laydown Yards Tensioning Areas Post Project Reclamation New T-Line Removal New T-Line Access Road
Slide 29: Burntlog Route
BURNTLOG ROUTE • Growth Media Salvage • Post Construction Reclamation • Post Project Obliteration of New Road • Post Project Narrowing of Upgraded Roads • Post Project Growth Media Replacement
Slide 30: Performance Standards & Maintenance
PERFOMANCE STANDARDS & MAINTENACE GOAL Demonstrate compliance with CFR 36 Chapter II Part 228 and reclamation and closure plan in accordance with IDAPA 20.30.02 and approved by IDL PROCESS Integrated with compliance and site monitoring programs (adaptive management) USFS, IDL and Midas Gold will for
Slide 31: Reclamation Summary
RECLAMATION SUMMARY Reclamation of 1,539 acres (81%) Concurrent Reclamation of 457 acres Placement of almost 2,000,000 CY of GM Live Handling of over 150,000 CY of GM Increased proposed GM placement from 6” in original PRO to 12” over DRSFs and TSF.