Tundra Mine Remediation Project Water Licence Renewal Public Hearing July 28, 2016
Outline 1. Tundra Mine – Then and Now 2. Project Schedule 3. Phase II Finalization a. Remediation Overview b. Adaptive Management Overview 4. Phase II Remediation Components a. Mill Pond Drawdown b. Water Treatment – effluent Quality 5. Long Term Monitoring 6. Management Plans 2
Outline 2. Project Schedule 3. Phase II Finalization a. Remediation Overview b. Adaptive Management Overview 4. Phase II Remediation Components a. Mill Pond Drawdown b. Water Treatment – effluent Quality 5. Long Term Monitoring 6. Management Plans 3
Tundra Mine Location Tundra is situated 240 km northeast of Yellowknife, Northwest Territories 4
Tundra Mine history • Former underground gold mine –First staked in 1945 –Tundra Gold Mines operated the mine 1964-68 –Giant Yellowknife Mines used site for tailings disposal from the nearby Salmita Mine 1983-1987 –Royal Oak Mines purchased site in 1992 • Royal Oak Mines went into receivership in 1999 and the site reverted to the Crown 5
Tundra Mine Site Layout 6
Tundra Mine – Phase II Remediation Overview Contaminants • Arsenic rich tailings (~290,000 m 3 ) • Arsenic impacted tailings water (originally1.2 million m 3 ) • Potentially Acid Generating (PAG) waste rock (~135,000m 3 ) • Petroleum hydrocarbon (PHC) contaminated soil and waste rock (originally ~16,000 m 3 ) Phase II Remediation – Technical Objectives • Treatment of PHC soils • Consolidation of tailings and waste rock • Construction of engineered cap over tailings and waste rock • Treatment of tailings impacted water 7
Tundra Mine – Pre-Remediation 8
Phase II – 2010 to 2014 1. Tailings Water Treatment & Discharge - 1,545,725 m 3 of tailings water successfully treated and discharged to Hambone Lake 2. Consolidation of ~112,000 m 3 of waste rock into the Tailings Containment Area (TCA) (task ~80% complete). 3. Consolidation of ~290,000 m 3 of tailings into the TCA - (task ~82% completed). 4. TCA Cap Construction - 60% of liner installed and approximately 25% earth cover complete 5. West Lower Pond Borrow Area (WLPBA) – Stockpiles completed with minimal future expansion anticipated 6. Site Stabilization - several berms were constructed throughout the Site to assist with water management to minimize contact with residual tailings. Maintenance of these Site features is included under C&M. 7. Successful treatment of 16,085 m 3 of PHC contaminated soil and waste rock 9
Present State Photo: August 2014 10
Outline 1. Tundra Mine – Then and Now 3. Phase II Finalization a. Remediation Overview b. Adaptive Management Overview 4. Phase II Remediation Components a. Mill Pond Drawdown b. Water Treatment – effluent Quality 5. Long Term Monitoring 6. Management Plans 11
Tundra Mine Remediation Project Remaining Timeline 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 Regulatory Approvals Contractor Hire Contractor Mobilization Phase II Remediation • 2 summers • Demob winter 2019 Adaptive Management Short Term Monitoring (5 years) Regulatory Approvals for LTM Long Term Monitoring 12
Outline 1. Tundra Mine – Then and Now 2. Project Schedule 4. Phase II Remediation Components a. Mill Pond Drawdown b. Water Treatment – effluent Quality 5. Long Term Monitoring 6. Management Plans 13
Phase II – Remaining Remediation • Mobilization of new contractor – Feb 2017 • Water treatment • Quarry development and reclamation • Dam removal (Mill Pond drawdown) • Consolidation of final 5% of tailings and waste rock • Finish TCA Cap • Finalize channels (Mill Pond to Hambone Lake) • Site stabilization • Install LTM equipment • Demobilize equipment and waste – Feb 2019 14
Remediation Phase to Adaptive Management Phase II Remedial Objectives • Construct TCA: Contain PAG waste rock and Tailings • Treat impacted water (Type A Trigger) • Treat PHC contaminated soil and waste rock Type A WL Triggers 1. Direct Water Use over 300 m 3 /day (operations and water treatment) 2. Dams – retention >60,000 m 3 15
Remediation Phase to Adaptive Management Meeting remedial objectives removes Type A triggers: • Completion of TCA: –water treatment no longer required –direct water use falls below 300 m 3 /day • Dam removal and channel construction –no longer retain >60,000 m 3 Remedial Objectives will be achieved once free flow is restored between Mill Pond and Hambone Lake. This milestone will mark the completion of the Remediation Phase and the commencement of the Adaptive Management Phase. 16
Adaptive Management Phase Scope • Monitoring/inspecting remediation features (TCA, channels, stabilization structures, etc.) to verify performance and general site stability (e.g. sediment and erosion concerns) –Site presence: freshet full time(?), monthly, and as required • SNP program • Response to identified concerns: –Potential to maintain a small camp and limited equipment on site –Perform repairs, maintenance, and general earthworks as required –Manage water as required 17
Adaptive Management Phase Timeline – Adaptive Management will continue until the site has reached a steady state, where no annual works are required to maintain the remedial objectives. – Anticipated 2019 to 2023, which will go to the end of MV2016L8-0003 and MV2016X0011 Long Term Monitoring Phase LTM will commence once the Adaptive Management Phase the site has reached a steady state (anticipated 2024) 18
Monitoring Phase II Remediation - Continuation • SNP program for baseline and construction monitoring –Identical to current SNP with the removal of groundwater monitoring wells that have been intentionally destroyed during remediation work (e.g. tailings and dam wells) • Annual geotechnical inspection 19
Monitoring Adaptive Management • Monthly SNP program for baseline monitoring –Maintains current SNP program with the following updates: –Remove: effluent discharge, destroyed wells, dam seeps (dry) –Relocate: Seep 6 station to capture potential sewage discharge, Upper and Lower Pond stations to capture water moving through site • Follow-up aquatics monitoring in year 1 (as per MV2009L8- 0008) • Annual geotechnical inspection and TCA monitoring 20
Monitoring Long Term Monitoring (covered under new Type B LUP and WL) • Annual monitoring program • LTM baseline based on: – Human Health and Ecological Risk Assessment (2016); – Status of Environment Report (2020); and – Adaptive Management monitoring results (2019-2023) 21
Site Condition – post remediation Human Health and Ecological Risk Assessment (SENES 2008) • Post-remediation water quality predictions for metals, low risk to human health and ecological organisms • Compared predicted water quality against CCME –Hambone Lake sediments too impacted by historic mining to comply with CCME –Powder Mag Lake may have periodic exceedance of CCME –Sandy Lake likely to remain compliant with CCME 22
Tundra Mine Site Layout 23
Site Condition – post remediation 2016 HHERA • Repeat HHERA to determine if assumptions/predictions of 2008 HHERA were correct • Determine more accurate predictions for post-remediation water quality and risk to downstream environment • Used to establish a downstream water quality compliance point and criteria 24
Outline 1. Tundra Mine – Then and Now 2. Project Schedule 3. Phase II Finalization a. Remediation Overview b. Adaptive Management Overview b. Water Treatment – effluent Quality 5. Long Term Monitoring 6. Management Plans 25
Mill Pond Drawdown East Upper Dam (EUD) must be removed to meet remedial objectives. Removal of the EUD will remove tailings impacted material, restore Mill Pond pre-mining water level, and restore the pre-mining drainage pathway from Mill Pond to Hambone Lake. General Process 1. EUD removal will require the Mill Pond water level to be temporarily lowered ~1.5m (~442.5 masl) 2. EUD will be excavated, followed by construction of a Mill Pond drainage channel 3. Mill Pond will return to the pre-mining water level and flow towards Hambone Lake 26
Mill Pond Drawdown 27
Mill Pond Drawdown 28
Mill Pond Drawdown 29
Mill Pond Drawdown Drawdown Process Primary Option • Pump Mill Pond Water direct to Hambone Lake* –~132,000 m 3 required to lower water level 1.5 m (442.5 masl) –Additional pumping may be required to maintain the required 442.5 masl during excavation and construction (recharge dependent) –Mill Pond would recharge to pre-mining water level 30
Mill Pond Drawdown Drawdown Process Secondary Option • Install a temporary Aquadam between Mill Pond and the EUD • Current water level would be retained during excavation and construction • Following completion of discharge channel, Aquadam would have controlled dewatering (~132,000 m 3 ), which would Lower Mill Pond to pre-mining water level 31
Mill Pond Drawdown Aquadam Option 32
Mill Pond Drawdown 33
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