Tundra Mine Remediation Project Water Licence Renewal Public - - PowerPoint PPT Presentation

Tundra Mine Remediation Project

Water Licence Renewal Public Hearing

July 28, 2016

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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

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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

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Tundra Mine Location

Tundra is situated 240 km northeast of Yellowknife, Northwest Territories

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

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Tundra Mine Site Layout

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Tundra Mine – Phase II Remediation Overview

Contaminants

• Arsenic rich tailings (~290,000 m3)
• Arsenic impacted tailings water (originally1.2 million m3)
• Potentially Acid Generating (PAG) waste rock (~135,000m3)
• Petroleum hydrocarbon (PHC) contaminated soil and waste rock

(originally ~16,000 m3)

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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

Tundra Mine – Pre-Remediation

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Phase II – 2010 to 2014

• 1. Tailings Water Treatment & Discharge - 1,545,725 m3 of tailings water

successfully treated and discharged to Hambone Lake

• 2. Consolidation of ~112,000 m3 of waste rock into the Tailings

Containment Area (TCA) (task ~80% complete).

• 3. Consolidation of ~290,000 m3 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 m3 of PHC contaminated soil and waste

rock

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Present State

Photo: August 2014

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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

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Regulatory Approvals Contractor Mobilization

2025 2024 2023 2022 2021 2020 2018 2017 2016 2019

Remaining Timeline

Adaptive Management Phase II Remediation

• 2 summers
• Demob winter 2019

Tundra Mine Remediation Project

Contractor Hire Long Term Monitoring Short Term Monitoring (5 years) Regulatory Approvals for LTM

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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

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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

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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 m3/day (operations and water

treatment)

• 2. Dams – retention >60,000 m3

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 m3/day

• Dam removal and channel construction

–no longer retain >60,000 m3 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.

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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

• n site

–Perform repairs, maintenance, and general earthworks as required –Manage water as required

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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)

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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

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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

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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)

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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

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Tundra Mine Site Layout

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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

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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

Mill Pond Drawdown

East Upper Dam (EUD) must be removed to meet remedial

• bjectives. 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

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Mill Pond Drawdown

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Mill Pond Drawdown

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Mill Pond Drawdown

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Mill Pond Drawdown

Drawdown Process Primary Option

• Pump Mill Pond Water direct to Hambone Lake*

–~132,000 m3 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

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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 m3), which would Lower Mill Pond to pre-mining water level

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Mill Pond Drawdown

Aquadam Option

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Mill Pond Drawdown

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Mill Pond Drawdown

Discharge to Hambone

• To remain protective of downstream channel stability, a

maximum discharge rate of 300 m3/hour to Hambone Lake from all sources will be applied Updated Water Licence Renewal Application

• The MV2016L8-0003 application has been updated to

include the detail of the Mill Pond drawdown in the following sections: –4 Description of Undertaking; –7 Quantity of Water Involved; and –10 Predicted Environmental Impacts and Proposed Mitigation

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Outline

• 1. Tundra Mine – Then and Now
• 2. Project Schedule
• 3. Phase II Finalization
• a. Remediation Overview
• b. Adaptive Management Overview
• a. Mill Pond Drawdown
• 5. Long Term Monitoring
• 6. Management Plans

Effluent Quality

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Remedial Approach - Treatment and discharge of arsenic-impacted tailings water

• Water treatment method

–iron co-precipitation –widely employed at mine sites for arsenic removal

• Treated water will be discharged

to Hambone Lake –Compliance point end of pipe

Effluent Quality

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• 1. Human Health and Ecological Risk

Assessment (HHERA) completed in 2008 –Assessed the effects of various effluent discharge scenarios –Incorporated the input of seepage from TCA –Assessed the effects of long term arsenic loadings (post-remediation)

• 2. Analysis of performance data for plants using

Best Available Technology (BAT)

• 3. Recommendations of water treatment experts

Selection of criteria for tailings discharge

Effluent Quality

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HHERA

• Hambone Lake

– Several species are potentially at risk in Hambone Lake due to pre-existing baseline conditions in the lake – None of the treated effluent discharge alternatives would have a substantively greater negative effect on current conditions in Hambone Lake

• Powder Mag and Sandy Lake

– None of the treated effluent discharge scenarios with effluent arsenic levels of 0.2 mg/L or less (2-year discharge) are predicted to pose risks to aquatic species – While phytoplankton might be affected temporarily in Powder Mag, the overall risk of adverse effects is judged to be low as the arsenic level recovers quickly and only very sensitive phytoplankton species would possibly be affected

Effluent Quality

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Hambone Powder Mag Sandy Whale Tail

Summary of Risks

Effluent Quality

Effluent Quality

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Best Available Technology (BAT)

• Analyzed data from full scale plants located at
• perating mines.

–Results indicate plants using BAT technology can meet a specification of 0.2 mg/L on an annual average basis, but not on a monthly basis.

• The plant at Tundra will use BAT technology

however it will encounter challenging operating conditions compared with other plants. –Shorter operational period –Remote Northern location

Effluent Quality

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Proposed Discharge Criteria

• Short term risks are present however it is

anticipated that downstream lakes will recover in the long term (SENES 2008)

• The water treatment contract will motivate the

contractor to achieve a discharge water quality of 0.2 mg/L Arsenic

Monthly Avg (mg/L) Max Grab (mg/L) Arsenic 0.5 1.0

Effluent Quality

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Proposed Discharge Criteria (Cont’d)

Treatment under MV2009L8-0008

• Consistently met discharge criteria
• One discharge sample in 2009 with arsenic >0.4

mg/L

• Consistent feedstock for stable treatment

conditions

• Annual treatment shutdown when TSS indicators

threatened arsenic exceedances

Effluent Quality

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Proposed Discharge Criteria (Cont’d)

Treatment under MV2009L8-0003

• Proposing same discharge criteria as MV2009L8-

0008

• Inconsistent feedstock due to treatment of final

portions of tailings impacted water containing high levels of TSS

• TSS highly correlated with arsenic
• Maintaining discharge criteria unlikely to provide

any detectible negative impacts to water quality or to the aquatic receptors

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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
• 6. Management Plans

Long Term Monitoring Phase

covered under separate Type B LUP and WL

• Anticipated to begin in 2024, once Adaptive Management

Phase indicates the site is geotechnically stable and water quality has stabilized as per the HHERA.

• Sampling frequency reduced to once annually

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Long Term Monitoring Phase

LTM baseline condition and monitoring program based on:

• 1. Human Health and Ecological Risk Assessment (2016):

predicts long term impacts and rate of recovery

• 2. Status of Environment Report (2020): identify and

describe environmental risks remaining on site

• 3. Adaptive Management monitoring results (2019-2023):

will identify post-remediation environmental trends

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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

Management Plans and Reports

WL Condition Approved Plan Title(s) Approved Ver. Document Date Approval Date WATER LICENCE MV2009L8-0008 Part B, Item 09 Reclamation Plan N/A yet Part B, Item 10 Status of Environment Report N/A yet Part D, Item 01 Tundra Mine Tailings Wastewater Treatment Plant Design Report Original July 13, 2010 August 19, 2010 Part D, Item 03 Water Treatment Monitoring and Discharge Plan Original May 26, 2014 May 22, 2014 Part D, Item 09 Erosion, Sediment and Drainage Control Plan Rev 16 April 10, 2016 June 9, 2016 Part D, Item 11 Tailings Confirmatory Sampling Program Rev 2 May 11, 2011 May 27, 2011 Part D, Item 13 Hydrocarbon Contaminated Materials Treatment Plan Rev 4 April 9, 2014 June 19, 2014 Part D, Item 21 PHC Wastewater Facility Design Plan Original May 6, 2011 June 23, 2011 Part D, Item 23 PHC Wastewater Treatment Facility Operation and Maintenance Plan Original May 6, 2011 June 23, 2011 Part D, Item 26 Common Excavation Work Plan Originals May 11, 2011 May 27, 2011 Part D, Item 28 Tailings Containment Area (TCA) Cover Design Report Rev 1 June 29, 2012 January 2, 2013 Part D, Item 34 Development of Tundra Mine Construction Monitoring, Long-Term Monitoring, and Status of the Environment Programs Rev 1 January 1, 2011 June 9, 2011 Part D, Item 38 Incineration Management Plan Rev 9 May 17, 2014 October 31, 2014 Part D, Item 40 Sewage Facility Design Report Rev 6 January 31, 2014 April 24, 2014 Part D, Item 42 Sewage Disposal Facility Operation and Maintenance Plan Rev 3 January 31, 2011 April 28, 2011 Part D, Item 47 Off-site Waste Management Plan Rev 4 March 13, 2014 April 24, 2014 Part D, Item 50 Water Quality Monitoring Program Protocols and QA/QC Plan Original July 16, 2010 July 26, 2010 Part G, Item 01 Tundra Mine Remediation Spill Contingency Plan Rev 11 September 1, 2014 October 31, 2014 LAND USE PERMIT MV2009X0019 Part C, Item 36 Wildlife Management Plan for the Tundra Mine Original 21-Jul-10

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Management Plans and Reports

• 17 Management Plans and Reports approved under current

WL and LUP

• 1 design change for the land form of the TCA earth cover

prompted revision of the TCA Cover Design Report (submitted with renewal application) –Land form design optimized to distribute flow off the cover –Reducing flows and associated required volumes of riprap in the design –Bonus: reduces the West Lower Pond Borrow Area footprint to approximately half

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Management Plans and Reports

2 Outstanding submittals for MV2009L8-0008

• Reclamation Plan for roads and drainages will be provided

90 days prior to undergoing reclamation work (as per MV2009L8-0008)

• Status of Environment Report will be provided 18 months

following Phase II Remediation (2020)

–18 months will provide sufficient time to incorporate the final remediation year’s water quality monitoring results as well as the post-remediation aquatics monitoring findings –SOE Report will be used to refine the SNP program during the Adaptive Management Phase and LTM Phase

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Management Plans and Reports

• Unchanged project scope = No need to revise any plans
• Issued for Construction Engineered Drawings can be

provided as an appendix to the TCA Construction Design Report if required (following tender posting)

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THANK YOU

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Hydrocarbon Contamination

Hydrocarbon impacted material remedial objectives and MV2009L8-0008 excavation criteria:

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PHC near shore criteria PHC far shore criteria PHC fraction ppm PHC fraction ppm F1 970 F1 700 F2 380 F2 1,000 F3 2,500 F3 2,500 F4 10,000 F4 10,000

Hydrocarbon Contamination

• Values derived from CCME CWS technical guidance

document

• Far shore (>30 m from a waterbody)

–Applies CWS “Management Limit” criteria, applied with no human health or ecological risk –Majority of Tundra PHC ipmacts are at dpth in coarse mine rock that can’t support biological activity (i.e. no exposure pathway)

• Near shore (<30 m from waterbody)
• Applies CWS “Protection of GW for Aquatic Life” criteria

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Hydrocarbon Contamination

• Near shore (<30 m from waterbody)
• Applies CWS “Protection of GW for Aquatic Life” criteria
• CWS applies less conservative 10 m from waterbody

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Hydrocarbon Contamination

CCME CWS Table 4 provides Governing Exposure Pathways for PHC fractions “Residential/Parkland” Land Use: F1 - “Management Limit” (ML) is higher priority than “Protection of GW for Aquatic Life” (FAL), hence “Management Limit” having more conservative value. Likely due to toxicity. F2 – ML and FAL priorities are flipped, hence FAL having more conservative value.

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Land Use Permit

CARD recommends that the issuance of a single permit be maintained.

• Post devolution, single LUPs were maintained for federal

sites

• Frobisher Gas Well Remediation Project was issues a single

LUP post devolution

• A single LUP allows both Federal and Territorial Inspectors

to carry out their duties, within respective jurisdictions

• No financial gain to be had by Canada or GNWT

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