DE BEERS GAHCHO KUÉ PROJECT ICRP TECHNICAL WORKSHOP Yellowknife, NT October 7, 2016
CONTENTS OF THE INTERIM CLOSURE AND RECLAMATION PLAN 1. Executive summary 2. Introduction 3. Project environment 4. Project description 5. Permanent closure and reclamation 6. Progressive reclamation 7. Temporary closure 8. Integrated schedule of activities approaching permanent closure 9. Post-closure site assessment 10.Financial security Appendices A. Glossary of Terms and Definitions B. List of Acronyms, Abbreviations, Units, and Symbols C. Record of Engagement D. Supporting Documents E. Reclamation Research Plan 1 The De Beers Group of Companies
Gahcho Kué ICRP Section 5: Permanent Closure and Reclamation Section 6: Progressive Reclamation 2 The De Beers Group of Companies
PROJECT DESCRIPTION For closure planning, the mine is separated into the following 5 mine areas: • Open Pits • Mine Rock Piles • PK Disposal Areas • Infrastructure • Kennady Lake Progressive reclamation is built into the mine plan 3 The De Beers Group of Companies
1. OPEN PITS 5034 300m deep • • partially back-filled with mine rock and coarse PK ~2m-50m m to the surface Hear arne e • 250m deep • partially back-filled with mine rock, fine PK and coarse PK ~50 m to the surface Tuzo • 360m deep • filled with water from the water management pond • chemocline will form between the water management pond water and the freshwater cap 4 The De Beers Group of Companies
1. OPEN PITS - POST CLOSURE VISION OP1: allow for the establishment of sustainable aquatic ecosystem; OP2: physically stable Hearne Pit 5034 Pit Tuzo Pit 420.7 masl > 2.0 m ~> 50 m ~50 m ~140 m 250 m 300 m 360 m Waste Rock & PK Waste Rock & PK Dense Water 5 The De Beers Group of Companies
2. PROCESSED KIMBERLITE DISPOSAL AREAS Coarse PK (0.25 mm to 6.5 mm particle size) Non-PAG Trucked to CPK pile o 23.4 MT produced during life of mine o 2016-2021: Coarse PK Pile (~43%) o 2022-2027: Hearne/5034 (~47%), o 2022 CPK Progressive reclamation starts o Coarse Processed Kimberlite Facility Fine PK (<0.25 mm particle size) Non-PAG Pumped as thickened slurry o 10 MT produced during life of mine o 2016-2020: Fine PKC Containment Facility (~37%) o 2021-2027: Hearne Pit (~63%) o 2021: FPK Progressive Reclamation starts o Fine Processed Kimberlite Facility 6 The De Beers Group of Companies
2. FINE PK FACILITY – POST CLOSURE VISION PK1: prevent PK from entering surrounding environment PK2: physical stable 50 1 ~15 m ~1 m cap Fine PK • Height – variable, ~15 m high • ~2% Slope during operations • Filter dyke to contain solids, spillway to be installed at closure • Covered with a layer of coarse PK (1m) and mine rock (1.5m) • Permafrost will aggrade within the interior PK spigot location to be adjusted throughout operations (not required) 7 The De Beers Group of Companies
2. COARSE PK FACILITY – POST CLOSURE VISION PK1: prevent PK from entering surrounding environment PK2: physical stable Coarse PK Pile • Approximately 35 m high • Material will be graded to 4W:1H and include a mine rock cover (1m) • Permafrost will aggrade within the interior (not required) 4 1 ~35 m Coarse PK 8 The De Beers Group of Companies
3. MINE ROCK PILES – SOUTH AND WEST MINE ROCK PILES • 300 MT of waste rock will be generated (7.5%/22.5MT PAG) • Landfill waste and contaminated rock >31 m from OHWM o >50m from edge of pile o Capped with till, mine rock o • PAG rock in waste rock piles >15m from edge o Overlain by 2m of till/overburden o Below OHWM of Kennady Lake (420.7masl) o Above OHWM of Kennady Lake (421.5masl) o South Mine Rock Pile On 2m mine rock if not submerged o 9 The De Beers Group of Companies
3. WASTE ROCK PILE – ROCK PLACEMENT 2.2 to 2.4 2 m Till >15 m 1 PAG 420.7 masl PAG 10 The De Beers Group of Companies
3. MINE ROCK PILES – POST CLOSURE VISION MR1: stable slopes to limit risks to wildlife and people MR2: waste disposal areas are safe • ~100 MT of waste rock/pile • Top of pile elevation - ~550 masl • Original ground surface – variable ~430 masl • Overall height - ~120 m • Bench – 15 m height, 15 m width, 1.3:1V slope • Overall slope – 2.2H:1V to 2.4H:1V • Permafrost will aggrade within the interior (not required) • No cover or revegetation (commitment to further discuss with Aboriginal communities) 11 The De Beers Group of Companies
4. INFRASTRUCTURE All other structures constructed to support the Project. Notable components include: • Roads and the Airstrip • Power Plant and fuel storage • Accommodations complex • Processing Facility • Maintenance shops • Laydowns and warehouses • AN Storage Facility • Landfarm 12 The De Beers Group of Companies
4. INFRASTRUCTURE – POST CLOSURE VISION I1: Disturbed areas will be safe for people, wildlife, and vegetation • Buildings inspected and hazardous materials removed for off-site disposal • Salvageable equipment and materials will shipped off-site • Inert solid materials will be placed in the landfill areas within the Mine Rock Piles or the mined out Tuzo Pit • Soil contamination assessed, excavated and shipped off-site as needed • Final grading plan will be developed to restore natural drainage where possible • Scarifying and contouring of compacted surface soils (e.g. roads and airstrip) to encourage the natural revegetation process 13 The De Beers Group of Companies
5. KENNADY LAKE – CONSTRUCTION • Dyke A constructed • Southern basin = de-watered • 18.63 Mm 3 of water to pumped to A8 and N11 • Dykes used to control water • Fine PK facility constructed • Water monitored as per the SNP • Downstream monitored as per the AEMP 14 The De Beers Group of Companies
5. KENNADY LAKE – OPERATIONS • Northern basin = Water Management Pond • Fine PK added to Fine PK facility • Active mining of 3 pits • Mine Rock Piles are active • Dykes are constructed • Collection Ponds constructed • Annual discharge if water meets the EQC’s • Downstream flow mitigation to A8 15 The De Beers Group of Companies
5. KENNADY LAKE – ACTIVE CLOSURE AND REFILLING • Internal dykes lowered (B,J,N) to ~417 masl • Water Management Pond drains to Tuzo • Fish habitat enhancements created • External dykes breached (E,F, and G) to re-connect with upstream waterbodies. • Supplemental water pumped from N11 to Kennady Lake • Breach dyke K to connect with A7 • Breach dyke A – reconnect with the downstream 16 The De Beers Group of Companies
5. KENNADY LAKE – POST CLOSURE VISION KL1: functioning aquatic ecosystem KL2: stable banks KL3: small craft navigation Water Management Pond water will be at the bottom of Tuzo pit Chemocline will have formed Internal dykes will have been breached, enhanced or left in place so long as they do not pose a risk to navigation of small craft Lake level will be 420.7 masl = the same as baseline Water will be safe to drink and the fish will be good to eat 17 The De Beers Group of Companies
5. KENNADY LAKE – Re-establishment of Aquatic Ecosystem Fisheries Authorization (paraphrased) 4.1 Fish Habitat shall be re-established through re-filling of Kennady Lake, breaching of dykes, allowing fish to migrate back into the lake 4.2 Fish habitat features shall be constructed within the re-established Kennady Lake including finger dykes, artificial reefs, and littoral habitat near the pits 5.1.5 The use of the fish habitat features constructed within the lake shall be evaluated by demonstrating fish presence on the features at appropriate life stages as per the Fish Habitat Validation Plan submitted prior to final construction of the features 5.1.6 Once Kennady Lake is refilled, confirmation is required that each species of fish that occurred in Kennady Lake at baseline, are occupying the expected habitat types within Kennady Lake and that the habitat within the lake has the features required for those fish. The Fish Habitat Validation Plan will define the monitoring objectives 18 The De Beers Group of Companies
(AANDC et al, 2013) 19 The De Beers Group of Companies
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