Mount Polley Mining Corporation...In 2017, MPMC submitted a draft Reclamation and Closure Plan (RCP)...

Mount Polley Mining Corporation

an Imperial Metals company Box 12 Likely, BC V0L 1N0 T 250.790.2215 F 250.790.2613

2017 Annual Environmental and Reclamation Report for the Mount Polley Mine

Submitted to:

The BC Ministry of Energy, Mines and Petroleum Development (Mines Act Permit M-200)

And The BC Ministry of Environment and Climate Change Strategy

(Environmental Management Act Permit 11678)

Prepared by:

Mount Polley Mining Corporation Environmental Department

Box 12, Likely BC V0L 1N0

(250) 790-2215

Mine Manager: Dale Reimer

Environmental Superintendent: Stephen Monninger

March 29, 2018

Mount Polley Mining Corporation 2017 Annual Environmental and Reclamation Report

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EXECUTIVE SUMMARY

In 2017, Mount Polley Mining Corporation (MPMC) mined 5,541,709 tonnes (t) of ore and 21,645,205 t of

waste rock from the Cariboo Pit. Approximately 16% of the waste mined was potentially acid generating

(PAG), and was transported to the Temporary PAG Stockpile. Approximately 6,686,158 t of tailings were

deposited into the Tailings Storage Facility (TSF). Production rates in 2018 are projected to decrease as the

Cariboo Pit becomes non-economically viable and Springer Pit undergoes tailings removal. The current

permitted projected date of mine closure is 2022

Environmental management and monitoring in 2017 followed guidelines and procedures contained in the

Comprehensive Environmental Monitoring Plan (CEMP) and was in accordance with regulations contained

in Environmental Management Act (EMA) Permit 11678 and Mines Act Permit M-200. Mining activities

including production summaries and reclamation follow requirements contained in Mines Act Permit M-

200.

As permitted by the EMA Permit 11678, the Water Treatment Plant (WTP) operated intermittently in 2017

and discharged a total of 2,019,650m3 of water. Reporting to Environment Canada under the Federal Metal

Mining Effluent Regulations continued accordingly.

Environmental monitoring at the site was completed in accordance with the 2017 monitoring program

meeting objectives outlined in the monitoring plans that were submitted to and approved by the Ministry

of Environment and Climate Change Strategy (ENV). Any permit non-compliances and exceedance that

occurred were reported to the Director as required. One permit limit exceedance occurred at the discharge,

but the investigation concluded that the sample bottle was contaminated. Water chemistry results from

monitoring sites were compared with British Columbia ENV Water Quality Guidelines (BCWQG) for aquatic

life.

In 2017, there were no unauthorized releases of mine-affected water. There were five (5) spills reported to

Emergency Management BC.

Some issues that were out of the control of MPMC did occur in 2017 including:

1) The Mount Polley Mine site was evacuated on July 15, 2017 due to the forest fire situation in the


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Cariboo Interior. The effluent discharge ceased and the site monitoring program was subsequently

put on hold until mine personnel could return to work on July 31, 2017. Regulatory bodies were

notified of CEMP non-compliances during this period of evacuation and for a period of time

thereafter due to on-going road closures and post-evacuation safety procedures.

2) There were delays in getting permit approval and authorizations due to the provincial elections and

subsequent change in government.

In 2017, MPMC submitted a draft Reclamation and Closure Plan (RCP) Update. Limited progressive

reclamation such as seedling planting, and grass seeding, as well ongoing research for waste dumps and

passive treatment, were conducted in 2017.

Remediation of Hazeltine Creek and the floodplain areas continued in 2017; which included tailings removal,

ripping, mounding and planting of the adjacent terrestrial areas, and channel reconstruction for fish habitat.


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TABLE OF CONTENTS

List of Tables .......................................................................................................................................................................................... vi List of Figures ....................................................................................................................................................................................... vii Appendices .......................................................................................................................................................................................... viii Abbreviations and Acronyms .......................................................................................................................................................... ix Units ......................................................................................................................................................................................................... x Consultants and Laboratories ........................................................................................................................................................ x 1 Introduction ................................................................................................................................................................................... 1

1.1 Objectives ............................................................................................................................................................................ 1 1.2 First Nations and Stakeholders ................................................................................................................................... 5 1.3 Qualified Professionals .................................................................................................................................................. 8

2 Mount Polley Mine Project Overview ............................................................................................................................... 10 2.1 Project History ................................................................................................................................................................ 10 2.2 Current Project Status ................................................................................................................................................. 13 2.3 Environment .................................................................................................................................................................... 14

3 Environmental Management ............................................................................................................................................... 16 3.1 Water Management ..................................................................................................................................................... 16 3.2 Sediment and Erosion Control ................................................................................................................................. 20 3.3 Invasive Plant Management ...................................................................................................................................... 21 3.4 Waste Management ..................................................................................................................................................... 22 3.5 Incidents ........................................................................................................................................................................... 23

4 Data Quality Assurance/Quality Control ......................................................................................................................... 25 4.1 Environmental System Audits .................................................................................................................................. 25 4.2 Scheduling ....................................................................................................................................................................... 26 4.3 Field Methods ................................................................................................................................................................. 26 4.4 Quality Control and Data Quality Objectives ..................................................................................................... 27 4.5 Data Quality Review and Data Management ..................................................................................................... 36

5 Mine Site Environmental Monitoring ............................................................................................................................... 38 5.1 Contact Water Chemistry ........................................................................................................................................... 38 5.2 Seep Sampling ............................................................................................................................................................... 41 5.3 Groundwater Monitoring ........................................................................................................................................... 41 5.4 Climate .............................................................................................................................................................................. 43

6 Discharge System and Monitoring .................................................................................................................................... 48 6.1 Discharge System .......................................................................................................................................................... 48 6.2 Discharge Monitoring ................................................................................................................................................. 50 6.3 Discharge Toxicity Testing Results ......................................................................................................................... 61

7 Hazeltine Creek Aquatic Environment Monitoring ..................................................................................................... 64 7.1 Surface Water Monitoring ......................................................................................................................................... 64 7.2 Remediation .................................................................................................................................................................... 64 7.3 Periphyton ........................................................................................................................................................................ 64


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7.4 Groundwater ................................................................................................................................................................... 64 7.5 Fish Exclusion .................................................................................................................................................................. 65 7.6 Hydrology ........................................................................................................................................................................ 66

8 Aquatic Receiving Environment ......................................................................................................................................... 68 8.1 Surface Water Quality ................................................................................................................................................. 68 8.2 Lake Sampling ................................................................................................................................................................ 78 8.3 Hydrology ........................................................................................................................................................................ 84 8.4 Sediment Quality ........................................................................................................................................................... 87 8.5 Benthic Invertebrates ................................................................................................................................................... 87 8.6 Plankton, Chlorophyll a, and Secchi Disk............................................................................................................. 87 8.7 Fish ...................................................................................................................................................................................... 89

9 Terrestrial Monitoring ............................................................................................................................................................ 90 9.1 Wildlife Monitoring ...................................................................................................................................................... 90 9.2 Archaeological Resources .......................................................................................................................................... 92

10 Reclamation Program ............................................................................................................................................................. 93 10.1 Reclamation Cost Update .......................................................................................................................................... 93 10.2 Stability of Works .......................................................................................................................................................... 93 10.3 2017 Reclamation Activities ...................................................................................................................................... 95 10.4 2017 Reclamation Research Update ...................................................................................................................... 98 10.5 Five Year Reclamation Plan ..................................................................................................................................... 102

11 Mining Program ...................................................................................................................................................................... 104 11.1 Surface Development to Date ................................................................................................................................ 104 11.2 Underground Mining Program .............................................................................................................................. 106 11.3 Projected Surface Development ........................................................................................................................... 107 11.4 Salvaging and Stockpiling of Surficial Materials ............................................................................................. 107 11.5 Acid Rock Drainage/Metal Leaching Characterization Program and Waste Disposal .................... 110 11.6 Drainage Water Quality Monitoring .................................................................................................................... 115 11.7 Air Discharge Permit .................................................................................................................................................. 117

12 Summary and Conclusions ................................................................................................................................................. 118 13 References ................................................................................................................................................................................. 120


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LIST OF TABLES

Table 1.1 Summary of stakeholder consultation for the updated Communication Plan ........................................ 7 Table 1.2 Annual report sections reviewed by a Qualified Professional......................................................................... 8 Table 2.1 Summary of EMA Permit 11678 amendments ................................................................................................... 11 Table 3.1 Summary of EMA Permit 11678 authorizations for water discharge from the Mount Polley Mine .................................................................................................................................................................................................................. 17 Table 3.2 Water storage conditions at end of 2017 ............................................................................................................ 19 Table 3.3 Aggressive and native seed mixes for reclamation .......................................................................................... 21 Table 3.4 Chemicals and reagents stored at the Mount Polley Mine site .................................................................. 22 Table 3.5 Blasting products stored at Orica Ltd.’s Mount Polley Mine site................................................................ 22 Table 3.6 Hydrocarbon and Dangerous Goods Spills reported to Environmental Department in 2017 ........ 23 Table 4.1 MPMC full sampling suite .......................................................................................................................................... 26 Table 4.2 Water chemistry QC sample frequencies for MPMC monitoring programs .......................................... 28 Table 4.3 Duplicate Sample RPD Acceptance Criteria ........................................................................................................ 29 Table 4.4 Field replicate sample locations collected in 2017 ........................................................................................... 29 Table 4.5 Trip blanks sent for analysis in 2017 ...................................................................................................................... 32 Table 4.6. Summary of trip blank results that are 5x detection limit ............................................................................ 33 Table 4.7 Field blanks sent for analysis in 2017 .................................................................................................................... 34 Table 4.8 Equipment blanks taken in 2017 ............................................................................................................................. 35 Table 4.9 Summary of KEM1 blank results that are 5x detection limit ........................................................................ 35 Table 5.1 Sampling events in 2017 at contact water quality sites ................................................................................. 38 Table 5.2 Mount Polley Mine monthly precipitation, evaporation, and temperature data in 2017. ................ 43 Table 6.1 Sampling events in 2017 at discharge monitoring sites ................................................................................ 50 Table 6.2 Summary of acute BCWQG for aquatic life exceedances for aquatic life at HAC-12. ........................ 55 Table 6.3 Summary of chronic BCWQG for aquatic life at HAC-12. Note that this only applies during periods where five (5) samples were collected within 30 days. ....................................................................................................... 55 Table 6.4 Effluent discharge condition during IDZ sampling at QUL-58 .................................................................... 57 Table 6.5 Toxicity sampling events in 2017 at discharge and monitoring sites ....................................................... 61 Table 8.1 Sampling events in 2017 at surface water quality sites .................................................................................. 68 Table 8.2 Summary of acute BCWQG exceedances for aquatic life at surface water monitoring sites .......... 69 Table 8.3 Summary of chronic BCWQG exceedances for aquatic life at surface water monitoring sites. Note that this only applies to sites where five (5) samples were collected in 30 days. .................................................... 70 Table 8.4 Lake water quality sampling locations in 2017 .................................................................................................. 78 Table 8.5 Chlorophyll-a sampling events in 2017 ................................................................................................................ 87 Table 8.6 Secchi depth measurement events in 2017. ....................................................................................................... 89 Table 9.1 2017 wildlife observations at Mount Polley Mine ............................................................................................ 90 Table 10.1 Summary of EMPR reclamation inspection recommendations................................................................. 95 Table 10.2 Progressive reclamation completed at Mount Polley Mine as of December 31, 2017 ................... 97 Table 10.3 Metro Vancouver biosolids deliveries and applications at Mount Polley (2000 – 2014) ................ 99 Table 10.4 Five year progressive reclamation plan ............................................................................................................ 103


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Table 11.1 Mount Polley Mine site existing and projected disturbance ................................................................... 104 Table 11.2 Changes in disturbed areas with closure footprints .................................................................................... 107 Table 11.3 MPMC Soil Inventory as of Dec. 31, 2017........................................................................................................ 108 Table 11.4 Quantities of waste rock, tailings, low grade ore, and other mine waste as of December 31, 2017. ................................................................................................................................................................................................................ 111 Table 11.5 Summary of monthly mining production ........................................................................................................ 112 Table 11.6 Summary of ABA data from the operating pits in 2017. ........................................................................... 112 Table 11.7 Summary of monthly crusher mill rates in 2017 ........................................................................................... 113 Table 11.8 Summary of monthly mill production 2017 .................................................................................................... 114 Table 11.9 ABA results from 2017 monthly tailings composite samples .................................................................. 115 Table 11.10 Site drainage water quality monitoring locations, and sampling periods and frequencies ..... 116 Table 11.11 Heap leach sump level in 2017.......................................................................................................................... 117

LIST OF FIGURES

Figure 2.1 Mount Polley Mine property location .................................................................................................................. 12 Figure 5.1 Mount Polley Mine wind data for 2017 (left), and for 2013-2017 for Weather Station #1 (centre) and Weather Station #2 (right) .................................................................................................................................................... 44 Figure 5.2 Maximum, mean and minimum monthly temperature data for Mount Polley Mine (2017 versus average) ................................................................................................................................................................................................. 45 Figure 5.3 Monthly rainfall at Mount Polley Mine (2017 versus average) .................................................................. 46 Figure 5.4 Monthly snowpack at Mount Polley Mine (2017 versus average) ............................................................ 46 Figure 5.5 Mount Polley Mine monthly precipitation and evaporation in 2017. ..................................................... 47 Figure 6.1 Total copper concentrations in influent (E19) and effluent (HAD-03) in 2017. ................................... 53 Figure 6.2 Total suspended solids concentrations in influent (E19) and effluent (HAD-03) in 2017. .............. 54 Figure 6.3 Total copper concentrations at the edge of the IDZ (QUL-58) in 2017. ................................................ 59 Figure 6.4 Short and long term BCWQG for aquatic life total copper concentrations at QUL-58 in 2017 (depths averaged). ............................................................................................................................................................................ 60 Figure 8.1 Total copper results at QUL-18 .............................................................................................................................. 83 Figure 8.2 Total copper results at QUL-120a .......................................................................................................................... 84 Figure 8.3 Chlorophyll results from Polley Lake .................................................................................................................... 88


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APPENDICES

Appendix A: Permit 11678, 2016 CEMP (including approved changes)

Appendix B: Site locations and maps

Appendix C: PLC Meeting Minutes

Appendix D: Quality Assurance/Quality Control (Electronic format only)

Appendix E: Surface, Contact, and Drainage Water Quality Results (Electronic format only)

Appendix F: Groundwater Review and Results

Appendix G: Invasive Plant Management Plan

Appendix H: Hazeltine Creek and Discharge

Appendix I: Tetra Tech EBA Memos

Appendix J: Minnow Environmental Reports

Appendix K: Hydrological Monitoring

Appendix L: Lake Water Quality (Electronic format only)

Appendix M: Metro Van Research Paper

Appendix N: Waste Survey Data

Appendix O: Government Communication

Appendix P: Water Balance Calibration Memo

Appendix Q: Annual Status Form


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ACRONYMS AND ABBREVIATIONS

ABA Acid-Base Accounting ABR Anaerobic Biological Reactor ADSI Annual Dam Safety Inspection AMP Adaptive Management Plan ARD Acid Rock Drainage ARD/ML Acid Rock Drainage/Metal Leaching BC British Columbia BCR Biochemical Reactors BCWQG British Columbia ENV Water Quality Guideline BCWWQG British Columbia ENV Working Water Quality Guideline CCS Central Collection Sump CEMP Comprehensive Environmental Monitoring Plan CFIA Canadian Food Inspection Agency CMDRC Cariboo Mine Development Review Committee COPC Contaminant(s) of Potential Concern CWTS Constructed Wetland Treatment System DFO Department of Fisheries and Oceans DGR Dangerous Good Regulations DGT Diffusive Gradient in Thin Films Device DI Deionized Water DQO Data Quality Objectives DSR Dam Safety Review EDC Edney Creek EEM Environmental Effects Monitoring ELS Early Life Stage EMA Environmental Management Act EMP Environmental Management Plans EMPR Ministry of Energy, Mines and Petroleum Development ENV Ministry of Environment and Climate Change Strategy EoR Engineer of Record ERA Ecological Risk Assessment HAC Hazeltine Creek HHRA Human Health Risk Assessment HSRC Health, Safety and Reclamation Code for Mines in British Columbia IC Implementation Committees IDZ Initial Dilution Zone IM Imperial Metals KEM1 Kemmerer water sampler LCRS Leachate Collection Recycle System LTWMP Long Term Water Management Plan MDC Mine Drainage Creek MDL Method Detection Limit MESCP Main Embankment Seepage Collection Pond MMER Metal Mine Effluent Regulations


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MPMC Mount Polley Mining Corporation MTD Main Toe Drain NAG Non-Acid Generating NBD North Bell Dump NEZ North East Zone NPR Neutralizing Potential Ratio NW Temporary Northwest OMS Operation, Maintenance and Surveillance [Manual] PAG Potentially Acid Generating PAO Pollution Abatement Order PEEIAR Post-Event Environmental Impact Assessment Report PETBP Perimeter Embankment Till Borrow Pit PESCP Perimeter Embankment Seepage Collection Pond PLC Public Liaison Committee POI(s) Parameter(s) Of Interest QA/QC Quality Assurance/Quality Control QP Qualified Professional QPO Quantitative Performance Objectives QUL Quesnel Lake QUR Quesnel River RCP Reclamation and Closure Plan RDS Rock Disposal Sites RPD Relative Percent Difference SCIB Soda Creek Indian Band SERDS Southeast Rock Disposal Site SEZ Southeast Zone STD South Toe Drain SWE Snow water equivalent TAR Technical Assessment Report TDAR Tailings Dam Access Road ToR Terms Of Reference TSF Tailings Storage Facility TSS Total Suspended Solids VAN2 Van Dorn water sampler WHR Waste Haul Road WLIB Williams Lake Indian Band WTP Water Treatment Plant WTP-RC Water Treatment Plant – Recirculation Mode


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UNITS

°C degrees Celsius dt dry tonnes ft feet ha hectare(s) kg kilogram(s) km kilometer(s) L liter(s) m metre(s) masl metres above sea level m3 cubic metre(s) m3/s cubic metre(s) per second mm millimeter(s) mg/L milligrams per litre µS/cm micro Siemens per centimeter % percent ppm parts per million t tonne(s) tpd tonne(s) per day

CONSULTANTS AND LABORATORIES

ALS ALS Environmental Inc. Contango Contango Strategies Ltd. Golder Golder Associates Ltd. Maxxam Maxxam Analytics Inc. Minnow Minnow Environmental Inc. Nautilus Nautilus Environmental Inc. SRK SRK Consulting Inc. Tetra Tech EBA Tetra Tech EBA Inc. WaterSmith WaterSmith Research Inc.


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1 Introduction

Mount Polley Mining Corporation (MPMC) is required to submit annual reports; one to the British Columbia (BC) Ministry of Environment and Climate Change Strategy (ENV), and a second to the BC Ministry of Energy, Mines & Petroleum Resources (EMPR) as per the by Environmental Management Act (EMA) Permit 11678 and Mines Act Permit M-200, respectively. Beginning with the reporting year of 2000 and continuing through 2017, these two reports have been combined into one comprehensive report for submission to both ministries under the title of the 2017 Annual Environmental and Reclamation Report.

In 1995 and 1996, an environmental monitoring program, which expanded on previous studies from 1989 and 1990, was designed and implemented to support mine planning, operations, and reclamation activities at the Mount Polley Mine. The program included baseline studies documenting the pre-development land uses and the conditions of the aquatic and terrestrial ecosystems. This information provides the foundation upon which operational environmental monitoring programs were, and continue to be, based. The November 29, 2015 Permit 11678 amendment includes a revised condition, to develop a Comprehensive Environmental Monitoring Plan (CEMP) to evaluate the effects of mining-related activities on the physical, chemical, and biological characteristics of Hazeltine Creek (HAC), Edney Creek (EDC), Bootjack Lake, Morehead Creek, Polley Lake, Quesnel Lake (QUL), Quesnel River (QUR), and associated riparian and upland areas. The CEMP plan was submitted to the ENV on June 23, 2016 and is provided as Appendix A along with the amended EMA Permit 11678 from September 19, 2016 and April 7, 2017. Subsequent revisions to the CEMP were also submitted for review in 2017 but were not approved by ENV.

1.1 Objectives

Environmental monitoring according to the 2016 CEMP (Appendix A) is ongoing. The CEMP includes figures showing all monitoring locations, fulfilling both the requirements of the Mines Act Permit M–200 under the EMPR and EMA Permit 11678 (Appendix A) under the ENV. The objective of this monitoring is to assess the environmental effects of mining activities at Mount Polley Mine on the receiving environment.

Monitoring results for 2017 are reported in subsequent sections of this report as follows:

• Chemistry and quantity of surface, seepage, lake and groundwater;

• Aquatic biology;

• Water levels in groundwater wells;

• Stream flows and water levels;

• Meteorology (temperature, precipitation, snowpack, evaporation rates); and

• Wildlife observations.


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1.1.1 Reclamation Objectives

In accordance with the BC Mines Act and the Health, Safety and Reclamation Code for Mines in British Columbia, the primary objective of the Reclamation and Closure Plan (RCP) (MPMC, 2017a) is to:

“return all mine-disturbed areas to an equivalent level of capability to that which existed prior to mining on an average property basis, unless the owner, agent or manager can provide evidence which demonstrates to the satisfaction of the chief inspector the impracticality of doing so”.

To achieve these objectives, reclamation and closure prescriptions are continually being refined based on the results from the ongoing reclamation research program (Section 10). An updated draft RCP was submitted to the EMPR on January 15, 2017 (MPMC, 2017a). At the time of this writing, the draft RCP is under review by government.

The main objective of the reclamation program is to return all areas that have been disturbed by mining operations (except pit walls) to equivalent or greater land capability than existed prior to mining, on an average property basis. To achieve this objective, MPMC has proposed end land use objectives that are based on an ecosystem approach. The ecosystem approach considers all ecosystem components and the resulting ecosystem services in reclamation planning. These ecosystems can be mapped on appropriate areas of the landscape, but rather than limiting each area to one designated end land use (e.g., wildlife habitat), this approach will allow for multiple, compatible end land use objectives to be targeted. End land uses that are encompassed in the target ecosystems over time include forest cover, wildlife habitat, hunting, trapping, guide outfitting, traditional use, livestock grazing, and recreation.

An End Land Use Plan, included in the RCP, (MPMC, 2017a) has been developed that focusses on ecosystem rehabilitation as the main goal with a target towards ecosystems that existed prior to the development of the mine (Section 10). The End Land Use Plan also estimates shifts in the end land use objectives over time as the ecological trajectories of the ecosystem mature. This ensures that end land use planning is considered over the long-term and that a variety of end land uses can occur on the landscape over different temporal scales.

The following goals are implicit in achieving these end land use objectives:

• Long-term preservation of water quality within and downstream of decommissioned operations;

• Long-term stability of engineered structures, including the waste rock dumps, TSF (Tailings Storage Facility), and open pits, as well as all exposed erodible materials;

• Removal and proper disposal of all access roads, structures, and equipment not required after the Mine closes;


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• Natural integration of disturbed lands with the surrounding landscape and restoration of the natural appearance of the area after mining ceases; and

• Establishment of self-sustaining vegetation covers consistent with the end land uses.

Once these aspects are in place, flexibility exists to modify ecosystem composition, patch size, and vegetation mosaic and to provide additional structural components, as required. By reclaiming disturbed land to stable, functioning, locally appropriate ecosystems that can reasonably be expected to thrive on a specific landform or location, a variety of end land use objectives can also be met.

End land use objectives envelop a multitude of values that may exist beyond ecological conditions and are driven by what regulators, MPMC, First Nations, and local communities prefer for the landscape once the Mine is closed. End land use decision is influenced by several factors, including:

• Permit obligations;

• Regulatory requirements;

• Landform design;

• Surface and subsurface materials at closure;

• Surface water hydrology;

• Slope;

• Aspect,

• Elevation;

• Input from First Nations, local communities and stakeholders; and

• Traditional and cultural land use.

End land use objectives may be adapted over time as interests evolve; however, once a landform is constructed, the end land uses are limited to the conditions and ecological trajectories associated with the particular ecosystem that has been rehabilitated.

Site research that was initiated at the Mine in 1998 indicates that conifer growth on reclaimed waste rock dumps is an attainable goal for parts of the Mines Site. However, to create appropriate microsites for conifers that grow in later successional stages, it is often necessary to promote early successional stage vegetation growth, allowing the process of natural succession to establish suitable vegetation cover and moisture conditions. Establishment of early successional stage communities can effectively support functioning ecosystems. Over time, as succession and native species ingress occur at reclamation sites, climax forest communities will be established.

Rehabilitation of the Mount Polley Mine site’s wildlife capability will require development of self-sustaining vegetation that imitates pre-development cover. Recreation of the natural appearance and creation of suitable habitats will allow for natural integration of disturbed lands into the surrounding landscape and improve wildlife use and access over time once the Mine has reached full closure. Post-closure, as wildlife


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usage increases and public access to parts of the site is re-established, the government will have the opportunity to sanction the end land uses of hunting, guide outfitting, and trapping.

Similarly, livestock grazing is a compatible end land use as there is overlap in wildlife and livestock forage species and vegetative cover preferences. Other forms of outdoor recreation, including sport fishing, will be supported by maintaining appropriate water quality and aquatic habitats in receiving environment water bodies.

1.1.2 Ministry of Energy, Mines and Petroleum Resources

The 2017 Annual Reclamation Report for the EMPR, as required by Mines Act Permit M–200, requires a summary and description of the past year’s mining and reclamation program including:

• A summary of disturbed areas and surface development.

• Updated disposal or storage locations for tailings, waste rock, ore, overburden or other materials, and associated volumes.

• A description of the environmental protection program over the reporting year and projected changes to the program, including surface water and groundwater quality, water management, Acid Rock Drainage/Metal Leaching (ARD/ML) characterization and management, wildlife protection, and sediment and erosion control.

• Drainage monitoring programs, including flows and water quality.

• Geological characterization and material characterization test work.

• An update on completed site reclamation, reclamation research, and reclamation plans for the next 5 years.

• Reclamation liability cost estimates.

1.1.3 Ministry of Environment and Climate Change Strategy

As per the most recent amendment of EMA Permit 11678 (April 7, 2017; Appendix A), the 2017 Annual Environmental Report must include:

a) All monitoring sample quality results required under the permit.

b) An evaluation of quality assurance, including collection, sampling, and data handling protocols.

c) An evaluation of the treatment plant operation and control.

d) An evaluation of the impacts of the mining operation on the receiving environment from the previous year.

e) A summary of any non-compliance with the permit and other incidents that may have led to impacts to the receiving environment.


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f) An update to the water balance, and a calibration assessment of the water balance and water quality models

g) An assessment of the outfall dispersion and dispersion modelling for the Quesnel Lake discharge

h) An update to any modeling related to the Springer Pit groundwater seepage and its impacts on Bootjack Lake.

i) A progress update with respect to the final water management plan.

j) A review and update of the assessment of ARD potential and water quality impacts from mine waste management.

k) A comparison of monitoring data with water quality guidelines, predictions and targets.

l) An update on the progress of reclamation and any updates to the reclamation plan.

m) An evaluation of the effectiveness of the Surface Runoff and Mine Drainage Control programs.

n) A summary of the Public Liaison Committee meetings, and issues and concerns presented.

o) An evaluation of the Outfall and Pipeline Inspection programs.

p) Trend analysis (graphs) of water monitoring data at each site for the past five years.

The purpose of this document is to allow the ENV to: identify whether spills or incidents have been reported and addressed; evaluate permit compliance; identify environmental effects; verify predictions of effects; and identify whether the permit adequately protects the environment or if changes are required.

1.2 First Nations and Stakeholders

1.2.1 First Nations Engagement

First Nations with recognized claimed traditional territory for the Mount Polley Mine are the T’exelc (Williams Lake Indian Band; WLIB) and the Xatśūll First Nation (Soda Creek Indian Band; SCIB). In 2011 and 2012, MPMC executed Participation Agreements with the WLIB and the SCIB, respectively. In August 2016 and April 2017, MPMC and WLIB and SCIB (respectively) these agreements were renewed. Through these respective Participation Agreements, Implementation Committees (IC) were formed in order to facilitate open dialogue between each of the First Nations and MPMC, providing a formalized, regular venue to discuss environmental, social and economic matters related to mine development, operation, reclamation, and closure (e.g., mine updates, permitting, environmental protection, reclamation, employment opportunities, and potential joint ventures). Meetings have taken place since March 16, 2012 with the WLIB and since July 19, 2012 with the SCIB. Effective October 18, 2012, Joint IC meetings have been held with representatives from MPMC, the WLIB, and the SCIB, replacing the previous MPMC/SCIB and MPMC/WLIB Implementation Committee meetings. Joint IC meetings are held at a minimum on a quarterly basis, but typically more frequently. These meetings and associated documentation ((Terms of Reference (ToR), minutes, and action items) provide a well-defined constructive forum in which issues, reviews, and comments relating to the current and anticipated future operations of the Mount Polley Mine may be


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discussed. The 2017 Annual Environmental and Reclamation Report will be provided in its current form to the SCIB and the WLIB for review, and discussion. Any comments or concerns will be facilitated through the Joint IC.

Four (4) Joint IC meetings were held in 2017: January 11, 2017; March 8, 2017; April 12, 2017; and May 25, 2017. As a result of the forest fires and the recovery from the forest fires in 2017, no meetings were held after the May 25th meeting.

1.2.2 Regional Mine Development Review Committee

In 2014, the Regional (Cariboo) Mine Development Review Committee (CMDRC) was revived by the EMPR. The CMDRC is a regionally based multi-agency review committee chaired by the EMPR. Participants include representatives from MPMC, local, provincial, and federal government agencies and First Nations. Members of the public are also invited to participate on a topic-specific basis. One (1) CMDRC meeting was held on 2017.

The CMDRC also acts as a venue for communication related to permit amendment applications under the EMA permits, or other regulations administered by the ENV and the BC Ministry of Forests, Lands and Natural Resource Operations & Rural Development. While communication related to EMA permit amendments will be conducted as per the EMA Public Notification Regulation, information is presented through the CMDRC where possible in order to coordinate review and consultation with parallel Mines Act permit amendments and other updates on the Mount Polley Mine site. The goal being to make efficient use of CMDRC member’s (government, First Nations, and community representatives) time.

1.2.3 Public Liaison Committee

The intention of the Public Liaison Committee (PLC) is to provide an opportunity for MPMC to share information about mine activities and monitoring results with its members. These members are comprised of public stakeholders, First Nations and government. The members are then responsible for relaying information between MPMC and the group or individuals for which they are the Designated Representative.

MPMC held four (4) PLC meetings in 2017: February 16, 2017; June 14, 2017; October 5, 2017 and November 16, 2017. A meeting was scheduled for May 18, 2017; however, this was delayed until June as the Government representatives were unable to attend due to the extended interregnum period following the provincial election. A meeting was also schedule for August 17, 2017, however this was delayed due to the extended forest fire season which challenged the availability of members. Site tours were completed during the June 14 and October 5 meetings. Minutes for the February, October, and November 2017 PLC meetings are included in Appendix C. Minutes for the June 14 meeting were never finalized due to the forest fire evacuations.

The EMA Permit 11678 amendment issued April 7, 2017, required MPMC to develop updated ToR for the


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PLC in consultation with the committee members. Upon review of the existing ToR in 2017, the PLC came to the consensus that no updates to the ToR were required at this time. This was communicated with the Director on October 19, 2017 who ultimately approved the ToR on January 19, 2018.

The EMA Permit 11678 (Appendix A) requires that a summary of the PLC meetings and issues and concerns be presented in this annual report. MPMC has chosen not to provide this as a summary but instead has provided the meeting minutes in full in Appendix C.

In 2017, most of the PLC meetings were well attended with between 15 and 20 attendees at each meeting. Lists of the attendees are included in the meeting minutes in Appendix C. At each of the PLC meetings, MPMC provided a site update, an update on the water management planning including an overview of the water discharge system and the current water balance, and an update on all environmental monitoring. As outlined in the ToR, the PLC is intended to provide opportunity for MPMC to share information about mine activities and the results of monitoring programs with PLC members and for members to share such information with their respective community.

1.2.4 Communication Plan

The April 7, 2017 amended EMA Permit 11678 required MPMC to develop and submit an update to the Communication Plan, in consultation with stakeholders, by June 30, 2017. This plan addresses the sharing of environmental data with WLIB, SCIB, Cariboo Regional District and the community of Likely. This deadline was extended to October 20, 2017 to allow for more consultation, and then to compensate for the interruption caused by forest fires. Table 1.1 outlines the consultation that was undertaken for the update to the Communication Plan. Ultimately, the consensus was that the plan was complete as it was originally written in 2016 and did not require updating. The Plan was formally approved by ENV on January 19, 2018.

Table 1.1 Summary of stakeholder consultation for the updated Communication Plan


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Date Description

June 14, 2017 PLC Meeting

September 14, 2017 Email to Likely Community with Communication Plan attached. The email requested input from the community on the plan.

September 14, 2017 Email to Likely Community with an invitation to meet with MPMC and Imperial Metals (IM) representatives the evening of September 29, 2017 to discuss the Communication Plan.

September 18, 2017 Posted an invitation on the Likely Community website and Facebook page to meet with MPMC and IM representatives on September 29, 2017 to discuss the Communication Plan.

September 29, 2017 MPMC and IM representatives were in Likely and prepared to speak with community members about the Communication Plan. One community member attended.

October 5, 2017 PLC Meeting

1.3 Qualified Professionals

Section 2.15 of the EMA Permit 11678 requires, “All documents submitted to the Director must be signed by the author and where specifically required by this permit, authored and signed by a Qualified Professional [QP]”. Further to that, Section 3.9 requires, “Monitoring data and the analysis of that data, as it will be presented in the annual report, must be reviewed by a third party QP”. The sections of this annual report that fall under these requirements are provided in Table 1.2 along with the QP that has reviewed or authored that section. Seals, where appropriate, have been provided in the applicable appendix, which are also summarized in Table 1.2.

Table 1.2 Annual report sections reviewed by a Qualified Professional


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Section Qualified Professional Appendix

4.5.1 Russell Smith, RPF: WaterSmith Research Inc (WaterSmith) K

5.1 Barbara Wernick., R.P. Bio.: Golder Associates Ltd. (Golder) E

5.3 Jacqueline Foley, Geol; Connie Romano, P.Geo: Golder F

6.2-6.3 Barbara Wernick., R.P. Bio.: Golder H

7.4 Connie Romano: Golder; Reidar Zapf-Gilje, CSAP: Consultant to Golder F

7.6 Russell Smith, RPF: WaterSmith K

8.1-8.2 Barbara Wernick., R.P. Bio.: Golder H

8.1 Pierre Stecko R.P. Bio: Minnow Environmental Inc. (Minnow) J

8.3 Russell Smith, RPF: WaterSmith K

8.4 Pierre Stecko R.P. Bio: Minnow J 8.5 Pierre Stecko R.P. Bio: Minnow J 8.7 Pierre Stecko R.P. Bio: Minnow J


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2 Mount Polley Mine Project Overview

2.1 Project History

Mount Polley Mine, operated by MPMC (a wholly owned subsidiary of Imperial Metals Corporation), is an open pit copper/gold mine with an underground component, and has the capacity to process 20,000 to 22,000 tonnes per day (tpd) of ore. The Mine is located eight (8) kilometres (km) southwest of Likely and fifty-six (56) km (100 km by road) northeast of Williams Lake, BC (Figure 2.1). The Mount Polley Mine property covers 18,892 hectares (ha), which consist of seven (7) mining leases totaling 2,007 ha, and forty-three (43) mineral claims encompassing 16,855 ha. Mount Polley Mine concentrates are trucked to facilities at the Port of Vancouver, and then shipped to overseas smelters or transported by rail to smelters in North America.

Clearing of the site and construction of the entire facility began in 1995, with the mill commissioned in June 1997. In May 1997, the Mine received an ENV (previously the Ministry of Water, Land and Air Protection) Effluent Permit, EMA Permit 11678, issued under the provisions of the provincial EMA. This permit authorized the discharge of concentrator tailings, mill site runoff, mine rock runoff, open pit water, and septic tank effluent to a tailings impoundment. Approval of the “Mount Polley Mine Reclamation and Closure Plan” by the EMPR resulted in the issuance of Mines Act Permit M–200 in July 1997. The first full year of mining and milling at Mount Polley Mine took place in 1998. The mine suspended operations in October 2001 due to low metal prices, then reopened in December 2004, with mill production commencing in March 2005.

A summary of EMA Permit 11678 amendments is provided in Table 2.1.


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Table 2.1 Summary of EMA Permit 11678 amendments

Date Scope of Amendment 30-May-1997 Original permit 20-Oct-1997 Amended authorized tailings discharge rate (10,000 tpd increase) 12-Jun-1998 Amended reporting requirements 8-Sep-1999 Amended monitoring requirements 1-Feb-2000 Amended authorized tailings discharge rate (4,500 tpd increase)

7-Feb-2002 Approval to discharge effluent from the Perimeter Embankment Seepage Collection Pond (PESCP) and Main Embankment Seepage Collection Pond (MESCP); approval to store TSF supernatant and Mine Site contact water in the Cariboo and Bell Pits

4-May-2005 Amended authorized tailings discharge rate (5,000 tpd increase); discharge of groundwater to Polley Lake; updates to reference analytical procedures and monitoring program

17-Apr-2009 Amended monitoring, water level and supernatant characteristic requirements for the Cariboo and Bell Pits

7-Nov-2012 Approval to discharge to Hazeltine Creek 7-Jun-2013 Sulphate guidelines 9-Jul-2015 Tailings discharge to the Springer Pit 29-Nov-2015 Approval to discharge to Hazeltine Creek 4-Apr-2016 Discharge of additional tailings to the Springer Pit 9-Sep-2016 Hazeltine Creek discharge total suspended solids limit change 7-Apr-2017 Direct pipeline from Water Treatment Plant (WTP) to Quesnel Lake


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Figure 2.1 Mount Polley Mine property location


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2.1.1 Tailings Storage Facility Embankment Breach

On August 4, 2014, a breach occurred in the Perimeter Embankment of the TSF; this event is herein referred to as the “TSF embankment breach”. The TSF embankment breach released tailings, water, and embankment construction materials to the downstream environments of Polley Lake, Hazeltine Creek and Quesnel Lake. The ENV issued MPMC Pollution Abatement Order (PAO) 107461, dated August 5, 2014, ordering MPMC to attend to the environmental impacts of the TSF embankment breach. As of December 31, 2017, the PAO remains in effect and MPMC continues to meet its requirements.

2.1.1.1 Post TSF Embankment Breach Reporting

Following the TSF embankment breach, an environmental monitoring program was initiated in areas downstream of the TSF including Polley Lake and Hazeltine Creek, both of which were previously monitored under EMA Permit 11678 (Appendix A). Monitoring of these areas in 2014 and 2015 was carried out under the PAO; consequently, these monitoring results were presented in the Post-Event Environmental Impact Assessment Report (PEEIAR; MPMC, 2015a; submitted to the ENV on June 6, 2015; publicly available online) and PEEIAR Version 2 (MPMC, 2016a; publicly available online). Results from monitoring conducted in 2016 were presented Human Health Risk Assessment (HHRA), (MPMC, 2017b; publicly available online) and Ecological Risk Assessment (ERA), (MPMC, 2017c; publicly available online) which have both been approved by ENV. Monitoring results from 2017 are presented in this annual report. A Conceptual Remediation Plan was required by the PAO to address the remedial actions based on the findings, results, and conclusions on the risk assessments, and will be integrated in the updated CEMP. This plan was submitted on January 31, 2018 to ENV and is currently under review. It will be made public in early summer 2018.

2.2 Current Project Status

2.2.1 Mine Operations

Following the TSF embankment breach, mine operations ceased. Restricted operations, with tailings being deposited in the Springer Pit, commenced on August 4, 2015. On November 6, 2015, MPMC applied for an amendment to Mines Act Permit M–200 to allow for the return to full operations at the Mount Polley Mine, with use of the TSF for tailings deposition. A corresponding Mines Act Permit M–200 amendment was received from the EMPR on June 23, 2016. Authorization to resume deposition of tailings in the TSF under EMA Permit 11678 was received from the ENV on June 23, 2016. MPMC resumed deposition of tailings in the TSF on June 27, 2016.

Currently authorized operations allows for: open pit mining of the Phase 4 Cariboo-Springer Pit and Boundary Pit; underground development of the Boundary Zone; milling of up to a maximum of 8,200,000 t of ore per year with deposition in the TSF; and, construction and operation of the TSF up to an elevation of 970 metres above sea level (masl).

https://www.imperialmetals.com/assets/docs/mt-polley/2015-06-18-MPMC-KFR.pdf

https://www.imperialmetals.com/assets/docs/mt-polley/2016-06-03_1411734-124-R-Rev0-10000.pdf

https://www.imperialmetals.com/assets/docs/mt-polley/HHRA_11MAY_17.pdf

https://www.imperialmetals.com/assets/docs/mt-polley/Ecological-Risk-Assessment.pdf


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The current active project infrastructure consists of the Mill site, mining in the Cariboo Pit, two (2) rock disposal sites (RDS) (the Southeast Rock Disposal Site (SERDS), and the Temporary Northwest (NW) Potentially-Acid Generating (PAG) Stockpile), the TSF, as well as access roads, power lines, a tailings pipeline, drainage collection systems, and sediment/seepage control ponds. Additional active mining is ongoing in the Boundary Zone underground operation, with the portal in the bottom of the Wight Pit. The Boundary Zone Pit, the Pond Zone Pit, the Southeast Zone (SEZ) Pit, the Bell Pit, and the Springer Pit are not currently active. Back-filling of the Bell Pit and Pond Zone Pit with waste rock was completed in 2012, and the SEZ Pit was backfilled in 2013. A detailed mine site map is included in Appendix B.

No permits for operation beyond the Phase 4 Cariboo-Springer Pit development are in place; however, identified ore reserves indicate approximately ten (10) more (cumulative) years of viable mine life. Given the uncertainty around future operations and mine life, reclamation and closure planning described in this document are subject to review and updates.

2.3 Environment

2.3.1 Topography and Climate

The Mount Polley Mine property is located on the eastern edge of the Fraser Plateau physiographic sub-division, characterized by rolling topography and moderate relief. Elevations range from 920 masl at Polley Lake to 1266 masl at the summit of Mount Polley. Volcanic rocks general underlay this part of the plateau with inclusions of intrusive rocks. Most of the area is covered by a deposit of unconsolidated till which contains fluvial, lacustrine, and colluvial deposits. Some patches of organic soils are present in poorly drained areas (i.e., wetlands). The property is located in an alkali porphyry copper-gold deposit hosted in the Central Quesnel Belt along the Intermontaine Belt of BC.

The site is located within the Interior Cedar Hemlock biogeoclimatic zone. Local forests consist of Western red cedar, Douglas-fir, hybrid spruce, and subalpine fir, with a lesser presence of trembling aspen, black cottonwood, and paper birch. Much of the area has been harvested in commercial logging operations and is also used for cattle grazing.

Average annual precipitation in the study area is 670 millimetres (mm). Precipitation typically occurs as snowfall from November through March, with an average maximum of snowpack of 178 mm snow water equivalent occurring at the end of March (Golder 2015a). Average monthly temperatures at the Mount Polley Mine range from -6.0 degrees Celsius (°C) in January to 15.3 °C in July and August (MPMC 2016b). Prevailing winds are from the north-north-east and from the south-south-west near the TSF, and from the northwest (and to a lesser extent the southeast) near the mill, with a predominance of winds designated as calm (below 3 metres per second; Golder 2015a).


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2.3.2 Hydrogeology

The groundwater flow at the site occurs primarily in the bedrock units in response to recharge from precipitation in the area between Polley Lake and Bootjack Lake. Flow in the overburden is less significant due to its limited thickness and discontinuous nature. Prior to mining, the water table at the site generally followed the surface topography, but the water table was deeper below the topographic heights and shallower in the low areas. At that time, the direction of groundwater flow was inferred to be from the top of the ridge between Polley Lake and Bootjack Lake towards the low-lying areas associated with these lakes northeast and southwest from the ridge.

Mine dewatering has altered the groundwater flow pattern at the site, with the open pits and underground workings acting as sinks for groundwater flow. Mine dewatering lowered the water table elevation and created radial patterns of groundwater flow towards these facilities. At present, the Springer Pit water level is being drawn down and the pit lake acts as a groundwater sink. The currently available information suggests that some seepage from the lake towards Bootjack Lake could occur once the pit lake level reaches 1020 to 1030 masl elevation (Golder 2015a).


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3 Environmental Management

3.1 Water Management

A map of all drainages and watersheds around the mine site is provided in Appendix B. Further information regarding pre-mining drainage and watershed can be found in the RCP (MPMC, 2017a).

3.1.1 Evaluation of Effectiveness of Water Management

MPMC continually evaluates water management infrastructure through routine inspections to ensure that it performs as expected. In 2017, all water management infrastructure performed as intended and no unintentional releases of mine contact water occurred.

3.1.2 Water Management System Update

A map of the mine runoff collection and water management system as of the December 31, 2017 is presented in Appendix B. Changes to this system in 2017 include:

• Removal of pipeline from Springer Pit to the WTP. • A French drain was installed in a portion of the Central Collection Sump (CCS)/PESCP ditch to

accommodate buttress construction at the Perimeter Embankment. • Construction of a water discharge pipeline from WTP to Quesnel Lake. • Installation and commissioning of a permanent pumping system from the Perimeter Embankment

Till Borrow Pit (PETBP) to the TSF.

3.1.3 Water Management System Upgrades

MPMC completed and submitted a Water Management Plan and System Review to the EMPR on March 31, 2016, as required under conditions of Mines Act Permit M–200. This Water Management Plan and System Review provided an overview of water management planning at the Mount Polley Mine. An update on site works completed since the issuance of the July 9, 2015 Mines Act Permit M–200 amendment requiring its development; a review of the design criteria and operational requirements of the water management system, as completed by third party QPs; a summary of the outcomes of the third party review; and, planned work.

Bi-annual sump and ditch inspections (required under EMA Permit 11678 found in Appendix A) were completed in 2017, as well as daily water management infrastructure inspections, environmental monitoring, and other observational activities as per MPMC’s Operation, Maintenance and Surveillance (OMS) Manual (as well as part of MPMC’s Sediment and Erosion Control Plan; Section 3.2). Based on inspection results, upgrades and modifications (in addition to routine maintenance) were made to support


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continuous improvements of the site water management system. The following improvements to existing site contact water collection systems were conducted in 2017:

• Reconstruction of a small portion of the NW Ditch to allow for more capacity

• Repairing of small erosional feature on the bank of the CCS

• Reconstruction of the embankment at the Bootjack Creek Sump

• Reconstruction of the Mine Drainage Creek (MDC) Sump to limit seepage and increase capacity

• Reconstruction of pipe grades and drainage structures from the South Embankment Seepage pond, through and past the MESCP and to the PETBP.

3.1.4 Water Discharge Background

MPMC has a positive water balance and the annual surplus of water has increased over the life of the project as the mine footprint has expanded, necessitating the collection of surface runoff from a larger area. A surplus of water accumulated in the TSF and water was discharged to Edney Creek under EMA Permit 11678 during the period in the early 2000’s when the mine was in care and maintenance due to low metal prices. In November 2011, MPMC received an amendment to EMA Permit 11678 that allowed for discharge of tailings dam filtered water into Hazeltine Creek; however, permit restrictions on the quality and quantity of water to be discharged, discharge season, and water source did not allow MPMC to fully discharge the surplus water that was accumulating in the TSF. At the time of the TSF embankment breach, MPMC was actively pursuing permit amendments for a short-term discharge (reverse osmosis-treated water to Polley Lake, with the process reject stream (brine) stored in the TSF), to manage the surplus of water for a period of approximately three to four years while a long-term water management plan was developed.

Following the TSF embankment breach, MPMC had no permitted discharge, and all contact water was being stored in the Springer Pit. However, the mine site continued to have a positive water balance (Golder 2015a) and the Springer Pit has a finite capacity. Golder estimated (Golder, 2015a) that once the pit water elevation reaches approximately 1,030 masl, the water will exfiltrate to the groundwater and discharge towards Bootjack Lake. At 1,050 masl the Springer Pit will overflow. Therefore, a short-term water management plan was developed following the TSF embankment breach; MPMC applied for and received an amendment to EMA Permit 11678 (along with the required supporting permits and authorizations) for a short-term water discharge to be utilized in the interim, while consultation and planning was carried out to develop a long-term water management strategy. The short-term discharge expired on November 30, 2017, at which time the long-term water management strategy was implemented.

Table 3.1 provides a summary of water discharge authorizations from the Mount Polley Mine. The current authorized discharge is discussed in further detail in Section 6.

Table 3.1 Summary of EMA Permit 11678 authorizations for water discharge from the Mount Polley Mine


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Date Discharge Source Permitted Discharge Location Comments

7-Feb-2002 MESCP Edney Creek Discharge discontinued in 2005; no longer permitted.

7-Nov-2012 Dam filtered Hazeltine Creek Discharge discontinued in 2014; no longer permitted.

29-Nov-2015 Springer Pit, and site runoff and seepage collection water management systems

Quesnel Lake via Hazeltine Creek

Current discharge; see Section 6.

30-Nov-2017 TSF, and site runoff and seepage collection water management systems

Quesnel Lake via direct pipeline

Was not active in 2017; see Section 6

3.1.5 Short-Term Water Management Plan

On July 16, 2015, MPMC applied to the ENV for an amendment to EMA Permit 11678 to allow short-term (maximum two year) discharge of treated mine effluent to Quesnel Lake via the Hazeltine Creek channel which was constructed and armoured, but not fish bearing. The permit amendment was received on November 30, 2015, authorizing discharge until November 30, 2017. MPMC commenced discharging on December 1, 2015.

Construction of required pipelines and diffusers, and procurement of water treatment infrastructure was completed prior to October 30, 2015, as required by the July 9, 2015 Mines Act Permit M–200 amendment, and this infrastructure was incorporated into the site the December 15, 2015 Operation, Maintenance and Surveillance (OMS) Manual update. The environmental monitoring program was initiated, as described in Section 6.2.

Additional details on the discharge system and assessment of potential effects on the receiving environment are available in the Mount Polley Mine: Short Term Effluent Discharge Technical Assessment Report in Support of an Effluent Permit Amendment developed by Golder (2015a).

3.1.6 Long-Term Water Management Plan Development

MPMC developed a long-term water management plan in conjunction with the implementation of the short-term water management plan in 2016. Below is a list of the milestones from the EMA Permit 11678 amendments (Appendix A), which dictated the timeline for transition to the long-term water management plan:

• An Alternative Discharge Design and Construction Plan was due January 31, 2015. • A draft Long-term Water Management Strategy Technical Assessment Report was submitted June

30, 2016. The final report was submitted October 17, 2016 followed by the submission of the amendment application on October 20, 2016.


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• Development and implementation of an alternative to the discharge to Hazeltine Creek is required by November 30, 2017. The April 2017 amendment of the permit required completion by December 31, 2017.

• The short-term water discharge is authorized only for a two-year period, ending November 30, 2017.

• The long-term discharge is authorized until December 2022. • The pipeline to convey water to Quesnel Lake was the chosen option for the long-term water

management plan. The construction of the pipeline was completed in November 2017.

3.1.7 Water Balance

MPMC retains Golder to maintain a predictive water balance model for the Mount Polley Mine site using GoldSimTM software. This model generates probabilistic flow and water balance forecasts for site water management system components, and has been adapted to model conditions during operations, closure, and post-closure following reclamation work.

The GoldSim water balance model is used for planning purposes such as water discharge planning, with calibration and revised projections made based on actual observed site conditions (i.e., water levels and storage volumes). The model also undergoes routine validation through comparison of predicted and observed accumulations, based on actual climate conditions and water management data recorded from site. Model validation was most recently carried out in March 2018 for data covering the period January 2017 to December 2017. Golder provided a Water Balance Calibration Technical Memo but was not finalized at the time of the report submission and it will be submitted separately.

In addition to the GoldSim model developed by Golder, MPMC has an operational spreadsheet that is used to record, and track components of the on site water balance for operational purposes. Water storage conditions on site for 2017 are summarized in Table 3.2. Under conditions of Mines Act Permit M–200 authorizing the return to full operations and use of the TSF, Quantitative Performance Objectives (QPOs) were established. Some of the QPOs are specific to free water storage in the TSF. Under current authorizations, the TSF is operated with a ‘normal operation free water surplus between 1,000,000 m3 and 1,500,000 m3, and is authorized for temporary detention of water for contingency (e.g., freshet) storage provided that a minimum freeboard of 1.1 m is maintained.

A summary of the water storage conditions is presented in Table 3.2.

Table 3.2 Water storage conditions at end of 2017

Item 2017 Year End Change from 2016 Year End

Springer Pit Elevation (masl) 1004.52 -7.72 Springer Pit Volume (m3) - Total 5,052,074 -1,218,111


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Springer Pit Volume (m3) - Water 1,442,712 -1,218,111 Springer Pit Volume (m3) - Tailings + Interstitial Water 3,609,362 0.00 Cariboo Pit Water Elevation (masl) - (a) 0.00 Cariboo Pit Water Volume (m3) - (a) 0.00 TSF Elevation (masl) 958.46 5.78 TSF Volume (m3) - Total 9,324,976 5,106,312.00 TSF Volume (m3) - Water 1,993,032 253,217 Total Free Water Volume (Springer + Cariboo + TSF) 3,435,744 -964,894.30

Total Water Discharged (m3) 2,019,650 - 4,688,080 (a) Actively mining in Cariboo Pit. Sump being kept as low as practicable.

3.2 Sediment and Erosion Control

MPMC maintains a Surface Erosion and Sediment Control Plan. Measures conducted in 2017 as per this plan are summarized in Section 3.1.3 (excluding work being done related to the TSF embankment breach). Under Mines Act Permit M–200, the plan must be reviewed annually; the updated plan was submitted to the EMPR in January 2017 as an appendix to the updated RCP (MPMC, 2017a).

In addition, a minimum amount of required sediment and erosion control materials are kept on hand for emergency use.

3.2.1 Re-vegetation

MPMC recognizes re-vegetation as a critical aspect of site maintenance and reclamation. Disturbed areas are grass seeded on an ongoing basis to prevent erosion and invasive species establishment. Soil stockpiles and areas that are unlikely to be disturbed are typically prescribed a native seed mix (Table 3.3). Sites that may be re-disturbed (or where preventing establishment of native species is the primary goal) are typically prescribed an aggressive seed mix (Table 3.3). This mixture grows rapidly in the short term, but dies off allowing the ingress of native species from surrounding areas.

All non-active soil stockpiles on site were inspected for erosion and vegetative cover and any non-active stockpiles requiring additional vegetative cover and/or showing signs of erosion were added to the bi-annual (spring and fall) seeding list.

Seeding and re-vegetation took place at numerous locations at the mine site in 2017 (see Appendix B). It occurred primarily on soil stockpiles and along roadside ditches. Seeding also took place at disturbed areas around the WTP and the newly constructed discharge pipeline right of way. MPMC maintains an


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active Seeding List that serves to track areas that require seeding, their size, description and type of seed.

In addition to seeding ground covers, much of the re-vegetation objectives at the mine include the establishment of woody shrubs and trees. Both conifer and deciduous species are planted. MPMC recognizes the importance of appropriate seed source and selection for long-term success and endeavours to use local seed sources. All of the conifer management at the mine is consistent with provincial forest management practises as governed by the Forest and Range Practices Act. This includes participation in regional silviculture strategies, stocking standards, tree species selection, and seed planning and registration. Additional erosion control is provided through re-vegetation associated with site progressive reclamation described in Section 10.3.2.

Table 3.3 Aggressive and native seed mixes for reclamation

Species % by Weight Aggressive Seed Mix

Dahurian Wildrye 25 Slender Wheatgrass 30 Perennial Ryegrass 15 Timothy 5

Native Seed Mix Mountain Brome 25 Native Red Fescue 10 Rocky Mountain Fescue 14.31 Bluebunch Wheatgrass 25 Blue Wildrye 25 Fireweed 0.014 Big Leaf Lupine 0.68

3.3 Invasive Plant Management

Invasive plant species are managed under MPMC Invasive Plant Management Plan. This plan was updated in 2017 and is included in Appendix G. Invasive species management activities in 2017 included:

• Seeding of soil stockpiles that are not active and new disturbed areas (Section 3.2.1 as well as new reclamation sites that (unless they covered with freshly stripped soil that is expected to re-vegetate without seeding; Section 11.3.2) to promote establishment of native species.

• Use of only high quality grade seed (currently sourced from Premier Pacific Seed (Table 3.3). At a minimum, seed used is of the grade Common No.1 Forage Mixture (or better) or Canada No. 1 Ground Cover Mixture. All seed used meets or exceeds Canadian Food Inspection Agency (CFIA) and regional standards for presence of noxious weeds.

• Monitoring of soil stockpiles to evaluate presence of invasive species (Section 12.3.2).


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• Planting of trees and shrubs in reclamation areas deemed inactive for mining purposes in a timely fashion to encourage rapid canopy cover (Section 11.3.2).

• Completion of a formal invasive plant inventory by Spectrum Resource Group (Appendix G)

The invasive species currently known to be present at Mount Polley Mine that are listed in the 2017 Regional Strategic Plan for Invasive Plant Management by the Cariboo Chilcotin Coast Invasive Plant Committee (CCCIPC, 2017) are oxeye daisy, Canada thistle, orange hawkweed, yellow hawkweeds (non-native), and scentless chamomile. All of these plants have the priority ranking “3 – Established”, and are common and widespread, with widespread control not currently possible. As such, MPMC’s approach is to manage invasive species at this site such that they do not inhibit reclamation activities, with recognition that all outside sources (for example, cattle, wildlife, wind and water) pose challenges to eradicating invasive plants at the mine site that are widespread in the surrounding areas.

3.4 Waste Management

3.4.1 Storage

In its mining operations, Mount Polley Mine utilizes a variety of chemicals, reagents, and other products. At any one time, the approximate volumes of materials in Table 3.4 could be on site. In 2017, Mount Polley Mine accepted no mineral-enriched soil from the Vancouver shipping wharves.

Table 3.4 Chemicals and reagents stored at the Mount Polley Mine site

Materials Total Stored On Hand on Jan 1, 2018 PAX (Mill Reagent) 18,000 kg 6,800 kg Lime 100,000 kg 58,532 kg Polyclear 3180M 2,800 kg 3,628 kg Polyfroth W22C 21,000 kg 2,673 kg NaHS 18,000 kg 8,100 kg Methanol 5,000 L 17,400 L Vanpress (Coagulant) 39,295 kg 39,295 kg

Blasting product values shown in Table 3.5 are the maximum allowable limits that may be stored at any given time at Orica Ltd.’s Mount Polley Mine site and a snap shot of what was on hand on January 5, 2018.

Table 3.5 Blasting products stored at Orica Ltd.’s Mount Polley Mine site

Blasting Products Maximum Allowable Limits Stored On Hand on Jan 5, 2018

Ammonium Nitrate Emulsion 50 t 30 t Ammonium Nitrate Prill 100 t 65 t Sodium Nitrite 3000 kg 1500 kg Ethylene Glycol 4000 kg 4000 kg


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3.4.2 Recycling

MPMC recognizes the value of responsible waste management and recycling plays a big role in site waste management practices. Mount Polley Mine continues to recycle used materials including waste oil, scrap steel, batteries, plastic pails, electronic waste, light bulbs and associated fixtures, paper, cardboard, and beverage containers. In 2017, MPMC donated the funds generated by its beverage container recycling program to the Big Brothers and Big Sisters of Williams Lake.

Recycling and waste management educational presentations were provided to MPMC employees and contractors in Q4 2017 and Q1 2018. An overview of waste segregation procedures is also presented to all contractors and new employees during site orientation

3.4.3 Chemical, Reagent, and Contaminated Waste Disposal

Mount Polley Mine operations utilizes potentially hazardous chemicals, reagents, and other products that are subject to a waste disposal procedures. In 2017, Sumas Environmental Services Ltd. routinely removed and disposed of these waste products in an environmentally safe manner compliant with all relevant waste management legislation. Products removed include: aerosol cans; contaminated gasoline and diesel; waste oil (in drums); waste oil filters; waste grease fuel or oil soaked rags, debris, and floor dry; and leachable liquid toxic waste, such as glycol/anti-freeze mix. The site waste oil tanks are emptied and the oil removed from site by GFL Environmental. In 2017, MPMC collected a total of 212,900 L of waste oil. There was ~ 17,000 L of waste oil on site on Jan. 1, 2018. MPMC is registered with the ENV under the Hazardous Waste Regulation for generation and temporary storage of these materials.

3.5 Incidents

3.5.1 Spills of Hydrocarbon or Dangerous Goods

All spills of hydrocarbons, coolant, and chemicals are reported to the MPMC Environmental Department. In 2017, there were four (4) coolant spills and fifteen (15) hydrocarbon spills reported. Of these spills, five (5) were considered reportable to Emergency Management BC as outlined in the Spill Reporting Legislation (Table 3.6). Those spills were given Dangerous Goods Regulation (DGR) number, and recorded into the government database. All spills were cleaned up, and the materials were removed from site in environmentally safe barrels by Sumas Environmental Services Ltd.

Table 3.6 Hydrocarbon and Dangerous Goods Spills reported to Environmental Department in 2017


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*Note that only 20L spilled outside the building; the rest was collected in the crusher building.

WHR: Waste Haul Road

3.5.2 Water Releases

In 2017, there were no releases of mine-affected water.

Date & Time Reported DGR# Source Volume (L) (estimated) Material Location02-Jan-2017 15:00 15-037 Haul Truck 40 Hydraulic Oil In pit washrooms21-Jan-2017 9:00 10-012 Drill 60 Coolant Cariboo Pit 1036 Bench22-Jan-2017 8:00 16-3075 10-012 Drill 130 Hydraulic Oil Cariboo Pit 1120 Bench23-Jan-2017 13:00 Waste Oil Tank 25 Waste Oil Outside Pit Shop16-Mar-2017 14:00 15-018 Haul Truck 60-80 Coolant PAG Dump10-Apr-2017 9:30 20-018 Excavator 90 Hydraulic Oil Cariboo Pit 1024 Bench12-Apr-2017 19:15 17-0146 05-021 Shovel 800 Hydraulic Oil Cariboo Pit 1040 Bench20-Apr-2017 20:30 10-012 Drill 85 Coolant Cariboo Pit 1072 Bench20-Apr-2017 21:45 10-012 Drill 70 Coolant Cariboo Pit 1072 Bench20-May-2017 6:30 Oil line 700* 220 Oil Tertiary Crusher 321-Jun-2017 10:30 10-010 Drill 50 Diesel Fuel Fuel Docks02-Aug-2017 15:30 14-1528 10-008 Drill 200 Compressor Oil Cariboo Pit 1036 Bench22-Aug-2017 0:00 25-013 Loader 90 Coolant/Engine Oil Cariboo Access Stockpile

28-Aug-2017 20:30 15-002 Haul Truck 75 Engine Oil Back road to SERD04-Sep-2017 13:30 17-1914 15-019 Haul Truck 200 Hydraulic Oil SERD to WHR21-Sep-2017 0:00 Gear box breather 40 220 Oil Crusher08-Oct-2017 23:30 15-020 Haul Truck 50 Diesel Fuel Fuel Docks11-Nov-2017 20:00 20-018 Excavator 50 Hydraulic Oil Springer Pit 1132 Bench12-Nov-2017 4:00 17-2747 15-018 Haul Truck 150 Transmission Oil SERD to WHR


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4 Data Quality Assurance/Quality Control

The purpose of the data quality assurance/quality control (QA/QC) program is to verify the reliability of monitoring data through the implementation of procedures for controlling and monitoring the measurement and analysis process. The QA/QC program provides information for evaluation of the analytical and monitoring procedures, and identification of issues pertaining to possible contamination, both in the field and in the analytical laboratory. The QA/QC program includes:

• Quality assurance (QA): management and technical practices designed to confirm that data were consistent with the objectives of the water quality program

• Quality control (QC): specific data quality objectives (DQO), statistical assessment of data quality, and corrective measures taken whenever the DQO were not met

The QA/QC program is conducted at all stages of the sampling program: sample collection, transport, and analysis for all sites including contact water quality sites, surface water quality sites, lakes, and groundwater wells.

MPMC maintains a Quality Assurance/Quality Control Manual (most recent version: MPMC, 2017d; herein referred to as the “MPMC QA/QC Manual” that is reviewed and audited annually. This manual oversees all the standard operating procedures and work methods pertaining to monitoring and sampling activities on the mine site.

4.1 Environmental System Audits

Environmental management plans (EMP) are based on the requirements set out by the EMA Permit 11678 and Mines Act Permit M–200 and are scheduled for updating and submitting accordingly. The following EMP were reviewed and updated in 2017:

• Environmental Emergency Response Plan • Hazeltine Creek Fish Exclusion Plan • Annual Discharge Plan • Outfall and Pipeline Inspection Plan • QA/QC Manual • CEMP • RCP • Invasive Plant Management Plan • Soil Management Plan


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4.2 Scheduling

To coordinate sampling and schedule all planned monitoring, as per the CEMP, MPMC prepares internal monthly sampling schedules.

4.3 Field Methods

4.3.1 Sample Collection

Sample collection was consistent with the procedures described in the current British Columbia Field Sampling Manual: 2013 – For Continuous Monitoring and the Collection of Air, Air-Emission, Water, Wastewater, Soil, Sediment, and Biological Samples (ENV, 2013) and MPMC QA/QC Manual (MPMC, 2017d). Monitoring procedures for the discharge locations (see Section 6) were consistent with the Metal Mining Effluent Regulations (Environment Canada, 2017), as appropriate.

4.3.2 Sample Suites

Each full sampling suite for water chemistry analysis consists of a variety of bottles. The type and volume of bottle will depend on the analysis and is determined by the BC Field Sampling Manual (ENV, 2013) and laboratory criteria (see Section 4.4):

Table 4.1 MPMC full sampling suite

Type and volume of bottle Name of analysis Type of analysis

500 mL clear plastic bottle

Nutrients-1 (surface and lake water)

pH, conductivity, turbidity, total dissolved, solids, hardness, alkalinity, chloride, fluoride, sulphate, phosphorus total and dissolved, and ortho-phosphorus

Nutrients-2 (groundwater only) pH, conductivity, hardness, alkalinity, chloride, fluoride, sulphate, phosphorus total and dissolved

TSS Whole bottle TSS

120 mL amber bottle Total ammonia and nitrogen Total nitrogen, nitrate, nitrite,

ammonia Dissolved organic carbon Dissolved organic carbon

60 mL plastic bottle Total metals See CEMP (Appendix A) Dissolved metals See CEMP (Appendix A)

In 2017, the full sampling suite for surface and lake water chemistry consisted of six (6) bottles: Nutrients-1, TSS, total ammonia and nitrogen, dissolved organic carbon, total metals and dissolved metals bottles. The full sampling suite for groundwater chemistry consisted of three (3) bottles: Nutrients-2, total ammonia and nitrogen and dissolved metals.


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4.3.3 Field Meters and Monitoring Equipment

Field meters were used to measure dissolved oxygen, conductivity, pH, temperature, turbidity, and water flow. Meters and other field equipment were operated and calibrated following the manufacturers’ instructions and the MPMC QA/QC Manual, which includes specific work methods for the equipment discussed below.

The conductivity and pH meters used for field analysis of surface water and groundwater were the WTW pH/Conductivity 340i and 3430 handheld multimeters. In-situ turbidity was measured with LaMotte 2020e and 2020we turbidity meters. For measuring field parameters in lakes, YSI EXO multimeters were used. Calibration records were recorded in the calibration logbook, as outlined in the MPMC QA/QC Manual (MPMC, 2017d). The YSI EXO multimeter was operated based on the equipment manual and guidance from the supplier (Hoskin Scientific), with general MPMC calibration practices being followed.

Flow measurements were taken using a Sontek FlowTracker Acoustic Doppler Velocimeter. The user measures flow rates across a creek or ditch cross section using the FlowTracker handheld device and the device then calculates the discharge rate based on these measurements and input parameters. The meter has QA/QC standards programed into it, and provides error notifications if these standards are not met. An International Organization for Standardization and statistical U.S. Geology Survey percent error are calculated for each discharge reading based on depth, velocity, width, method, number of stations, and calibration accuracy to evaluate accuracy of the discharge measurement. The dry salt slug injection tracer method was used by WaterSmith during benchmarking surveys and station assessments in August 2017 and was subject to WaterSmith’s QA/QC procedures .

The staff gauge benchmarking (calibrating) and hydrology station calibrating program occurs annually as required by Section 3.4 of EMA Permit 11678 and as per protocol in the MPMC QA/QC Manual (MPMC, 2017d). Station specific details are provided in Section 7.6 and 8.3.

Field secchi disk monitoring was undertaken in the lakes (see Section 8.6.2 ; Appendix K). To promote consistency, secchi disk readings are done whenever possible by the same technician throughout the season with a QA/QC check done annually by a more experienced staff member to evaluate consistency of the readings compared to other years.

Chlorophyll a, phytoplankton and zooplankton samples were collected as per the protocol in the MPMC QA/QC Manual (MPMC, 2017d). Chlorophyll a and zooplankton tissue metals analysis were sent to ALS (see Section 4.4). Enumeration and species identification of phytoplankton community and zooplankton taxonomy samples were sent to specialized labs, as described in the CEMP (Appendix A).

4.4 Quality Control and Data Quality Objectives

Analytical processing of samples collected by MPMC is conducted by ALS Environmental Ltd. (ALS) in


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Burnaby, BC. ALS is a Canadian Association for Laboratory Accreditation Inc. accredited laboratory for the analyses requested. The Laboratory DQO provided to MPMC by ALS are included as Appendix D.

Bioassay (toxicity) testing in carried out by Nautilus Environmental (Nautilus) in Burnaby, BC. Nautilus is Canadian Association for Laboratory Accreditation Inc. accredited laboratory for the analyses requested. Acute and chronic bioassays methods are conducted as outlined in the Metal Mining Effluent Regulations (MMER) Environmental Effects Monitoring (EEM) studies and EMA Permit 11678. The toxicity tests are scheduled 30 days prior to sampling as required by MMER (see Section 6.3). The laboratory QA/QC measures provided to MPMC by Nautilus are included as Appendix D.

Samples submitted were tracked to verify that laboratory sampling and analysis protocols were followed, including hold times, sample containers, preservatives, detection limits, and approved methodology. Instances in which these protocols were not followed were recorded in the sample tracking sheet. This spreadsheet tracked individual samples and recorded the locations of samples, along with the date, duplicate and blank sample information, sample shipping information, laboratory correspondence, analytical results, and potential data integrity issues.

4.4.1 Replicates and Blanks

For water chemistry, QC samples were collected as a component of the monitoring program as per the MPMC QA/QC Manual. The recommended minimum number of replicates and blanks is 10% of the overall samples set out by the current BC Field Sampling Manual (ENV, 2013). In 2017, MPMC achieved 13% of total QC samples. A combined QC schedule across the various MPMC monitoring programs as described in the CEMP is summarized in Table 4.2.

Table 4.2 Water chemistry QC sample frequencies for MPMC monitoring programs

QC Samples Minimum Frequency

Duplicate samples 2 per month

Equipment blanks Monthly per piece of equipment (when used)

Trip blanks Monthly

Field blanks Monthly

Filter blanks Quarterly

Deionized (DI) water blanks Annually

Intra-laboratory replicate Annually

4.4.1.1 Field Replicates

The semi-blind replicates are intended to evaluate the QA/QC surrounding the sampling methods. Replicates are prepared by collecting two full sample suites from one location at the same time, one after the other, labelling one with the sampling location name (e.g., E4, HAC-12) and labelling the second sample


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suite with a replicate name (e.g., ED, HAC-12x). When the results are reported back from the analytical laboratory, all parameters from the replicate and the actual sample are screened to confirm likeness, or potential of sampling error or contamination. The screening process also considers accuracy of the analytical procedures and small-scale natural variations in water quality which may occur over the timescale of collection (approximately 10 minutes). In particular, there is considerable potential for variations in water quality over short-time scales during periods of high sediment loads.

Semi-blind field replicates were compared to evaluate the precision of the methods used (i.e. combined precision of field methods, laboratory methods and the environmental variability between the side-by-side samples). A relative percent difference (RPD) is calculated to identify significant differences between the replicate and sample, where the RPD (as %) can be defined as:

RPD (%) = �𝑋𝑋𝑥𝑥 – 𝑋𝑋𝑦𝑦�

𝑋𝑋� × 100

Where 𝑋𝑋𝑥𝑥= the concentration of the original sample 𝑋𝑋𝑦𝑦= the concentration of the blind field duplicate sample

𝑋𝑋� = the average of the original and duplicate samples

The acceptance criteria for RPDs for water chemistry are defined as 1.5x the laboratory RPD criteria, which is summarized in Table 4.3. For results less than five times the detection limit, significant differences are identified if the difference of the two results is greater than twice the detection limit. When either sample is less than detection limit, differences are not calculated.

Table 4.3 Duplicate Sample RPD Acceptance Criteria

Analyte Group RPD Acceptance Criterion

Metals 30%

Inorganics 30%

Organics 45%

Other parameters 1.5 x Laboratory RPD

There were sixty-seven (67) field replicate samples collected in 2017, as shown in Table 4.4. The raw data is available in Appendix D. Note the prefixes refer to location areas (ie. ‘W’ refers to non-contact water site, ‘EDC-01’, refers to Edney Creek); additional information on naming conventions are found in the CEMP (Appendix A). There were no results for total metals analysis for the groundwater duplicates (e.g. GW15-1a) as total metals are not analyzed for groundwater samples. In addition, the BAC samples (eg. BAC-01) are only analyzed for E-coli and total bacteria coliform.

Table 4.4 Field replicate sample locations collected in 2017

Date Sampled Location Replicate Name

3-Jan-17 HAC-12 HAC-12X

5-Jan-17 W4a WD


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Date Sampled Location Replicate Name

1-Feb-17 HAD-03 HAD-C

14-Feb-17 E18 ER

21-Feb-17 HAC-13 HAC-M

2-Mar-17 W1 WA

6-Mar-17 QUL-58-B QUL-EH-B

20-Mar-17 GW15-1a GW15-1AX

21-Mar-17 E19 ES

28-Mar-17 WTP-RC WTP-RC dup

3-Apr-17 HAC-08 HAC-H

5-Apr-17 W5 WE

10-Apr-17 QUL-2a-40m QUL-Ba-40m

12-Apr-17 QUR-11 QUR-K

17-Apr-17 E19 ES

17-Apr-17 WTP-RC WTP-RC dup

2-May-17 HAC-10 HAC-J

4-May-17 GW12-3a GW12-Ca

4-May-17 W8 WH

10-May-17 GW96-1b GWIF-Ab

15-May-17 GW00-1a GWXX-Aa

25-May-17 W20 WT

28-May-17 QUL-18-20m QUL-R-20m

31-May-17 E19 ES

1-Jun-17 W10 WJ 7-Jun-17 GW16-7 GWP-G

20-Jun-17 HAC-13 HAC-M 21-Jun-17 QUL-120a-80m QUL-Ata-80m 22-Jun-17 GW15-2b GWO-Bb 28-Jun-17 P2-20m PB-20m 4-Jul-17 E1a EAa 4-Jul-17 HAC-12 HAC-L

3-Aug-17 W8b WHb 22-Aug-17 QUL-18-100m QUL-R-100m 24-Aug-17 GW16-6a GW16-FA 27-Aug-17 HAC-13 HAC-M 5-Sep-17 BAC-01 BAC-0A 5-Sep-17 W4a WDa 6-Sep-17 B1-B BA-B


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Date Sampled Location Replicate Name 12-Sep-17 QUL-2a-20m QUL-Ba-20m 13-Sep-17 GW12-5a GWL-Ea 13-Sep-17 95R-5 IE-RE 13-Sep-17 GW96-4b GWIF-Db 19-Sep-17 HAD-03 HAD-C 19-Sep-17 E19 ES 28-Sep-17 GW11-2b GWK-Bb 2-Oct-17 EDC-01 EDC-A

11-Oct-17 W1 WA 26-Oct-17 QUL-58-BT QUL-EH-BT 30-Oct-17 P1-S PA-S 2-Nov-17 GW16-2a GWP-Ba 7-Nov-17 HAC-08 HAC-H 9-Nov-17 W8z WHz

20-Nov-17 W12 WL 21-Nov-17 HAC-14 HAC-N 23-Nov-17 QUR-11 QUR-K 4-Dec-17 W10 WJ 4-Dec-17 E1a EAa 4-Dec-17 W5 WE 5-Dec-17 HAC-01c HAC-0Ac 5-Dec-17 HAC-05a HAC-Ea 5-Dec-17 HAC-10 HAC-J 5-Dec-17 POF-1 POF-A 7-Dec-17 QUL-58-S QUL-EH-S

13-Dec-17 GW15-2b GWO-Ba 19-Dec-17 BAC-03 BAC-0C

For total metal analyses, the applicable replicate criterion was exceeded on one (1) occasion for manganese (RPD = 40.2%), molybdenum (RPD = 49.9%), and zinc (significant difference = 0.0145 mg/L); and arsenic and lead on two (2) occasions. The significant differences for the arsenic exceedances were 0.00076 and 0.00055 mg/L. The significant difference for the one lead exceedance was 0.000126 mg/L and the other exceedance was above five times the detection limit and reported as a RPD of 51.7% (Table 1, Appendix D). Some degree of variability can be expected in replicate samples for parameters such as total metals, which are influenced by total suspended solids (TSS).

For dissolved metals analyses, the applicable replicate criterion was exceeded on one (1) occasion for molybdenum (RPD = 39.1%). On five (5) occasions, manganese exceeded the replicate criterion. Of those five (5), three (3) were less than five times the detection limit and the significant differences ranged from 0.00021 to 0.00047 mg/L. Two (2) of those (5) exceedances had results above five times the detection limits


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and those RPDs were 39.4% and 31.6%. (Table 2, Appendix D).

For general parameters (ammonia, nitrate, nitrite, sulphate, and TSS), two significant differences were identified for TSS (25.5 mg/L and 2.3 mg/L) (Table 3, Appendix D).

For E-coli and total coliform analysis, no differences were identified between samples. All results were below detection limit (Table 4, Appendix D).

There was one (1) inter-laboratory replicate collected in 2017. This replicate is intended to evaluate the QA/QC surrounding the analytical laboratory. This replicate was prepared as described above; the sample with the sampling location name is sent to ALS and the sample with the anonymous name is sent to Maxxam Analytics Inc (Maxxam) in Burnaby, BC. Maxxam is also a Canadian Association for Laboratory Accreditation Inc. accredited laboratory for the analyses requested.

There were no RPDs or significant differences identified in the inter-laboratory replicate (Table 5, Appendix D).

4.4.1.2 Blanks

Trip blanks and field blanks, prepared by the analytical laboratory, are exposed to the same conditions and treatments as the water samples collected and are intended to monitor contamination that may occur during sampling or shipping. Field blanks are opened and preserved at one of the sample locations to expose them to the natural environment and trip blanks remain closed at all times. Trip or field blanks are submitted to the laboratory with sample sets for total suspended solids, total metals, and nutrient and anion analysis, as well as dissolved organic carbon analysis for field blanks.

4.4.1.2.1 Trip Blanks

In 2017, twenty (20) trip blanks were submitted to ALS, as listed in Table 4.5.

Table 4.5 Trip blanks sent for analysis in 2017

Date Sampled Area

5-Jan-17 Mine Site

14-Feb-17 Hazeltine Creek

2-Mar-17 Mine Site

14-Mar-17 Hazeltine Creek

3-Apr-17 Hazeltine Creek

11-Apr-17 Quesnel Lake

19-Apr-17 Mine Site


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Date Sampled Area

4-May-17 Mine Site

7-Jun-17 Mine Site

18-Jun-17 Polley Lake

6-Jul-17 Mine Site

3-Aug-17 Mine Site

6-Sep-17 Mine Site 1-Oct-17 Quesnel Lake

11-Oct-17 Mine Site 30-Oct-17 Polley Lake 7-Nov-17 Edney Creek 9-Nov-17 Mine Site 4-Dec-17 Mine Site

20-Dec-17 Quesnel River

Total ammonia and total barium were above detection limits in one or more of the trip blanks (Table 6, Appendix D). However, only total ammonia was greater than five times the detection limit; results are provided in Table 4.6:

Table 4.6. Summary of trip blank results that are 5x detection limit

Date Sampled Parameter Detection Limit Result

1-Oct-17 Total Ammonia (mg/L) 0.0050 0.0479



04-Dec-17 Total Ammonia (mg/L) 0.0050 0.052

The trip blank parameters that are above detection limit are rechecked by ALS laboratory. A code is associated with the parameters in the results spreadsheet to indicate that the result was rechecked and verified. Communications with ALS identified that there was an ammonia contamination with the travel blanks (see Appendix D).

4.4.1.2.2 Field Blanks

Twenty-two (22) field blanks listed in Table 4.7 were submitted to ALS in 2017. Total ammonia, and total manganese were above detection limits in one or more of the field blanks; also potentially related to a lab contamination These results were within five times the reported detection limit so was determined not to affect the reliability of the data (Table 7, Appendix D).


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Table 4.7 Field blanks sent for analysis in 2017

Date Sampled Area 24-Jan-17 Hazeltine Creek 1-Feb-17 Hazeltine Creek 6-Feb-17 Mine Site 1-Mar-17 Hazeltine Creek 2-Mar-17 Mine Site 24-Apr-17 Mine Site 9-May-17 Quesnel Lake

25-May-17 Mine Site 7-Jun-17 Mine Site

20-Jun-17 Hazeltine Creek 21-Jun-17 Quesnel Lake 4-Jul-17 Hazeltine Creek 6-Jul-17 Mine Site

3-Aug-17 Mine Site 22-Aug-17 Quesnel Lake 6-Sep-17 Mine Site

20-Sep-17 Quesnel River 23-Oct-17 Mine Site 9-Nov-17 Mine Site

21-Nov-17 Hazeltine Creek 4-Dec-17 Mine Site 5-Dec-17 Hazeltine Creek

4.4.1.2.3 Filter Blanks

Filter blanks are prepared by filtering DI water and submitting for dissolved metals analysis. Four (4) filter blanks were submitted in 2017. All parameters analyzed in the filter blanks were below reported detection limits except dissolved barium from October 23, 2017 (Table 8, Appendix D).

4.4.1.2.4 DI Water Blanks

DI water blanks are prepared by submitting a full sample suite (minus dissolved metals since filter blanks are prepared) of DI water. One (1) DI water blank was submitted in 2017; all parameters were below reported detection limit as expected (Table 9, Appendix D).

4.4.1.2.5 Equipment Blanks

When conducting lake water quality sampling, an equipment blank sample is taken with the Van Dorn (VAN2) or Kemmerer (KEM1b) sampler monthly during each sampling program, such as spring overturn monitoring. Equipment blanks are submitted to the laboratory for full sample suites (minus dissolved metals


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since filter blanks are also prepared). Twelve (12) equipment blanks were taken in 2017, as shown in Table 4.8. One monthly blank was missed in July 2017 due to the evacuation from forest fires. VAN2 was not used in 2017, so only KEM1 blanks were taken. The lake sampling program in 2017 commenced in March and ended in December (see Sections 6.2 and 8.2). Note that KEM-1B equipment blanks were conducted in January and February as sampling from the Quesnel River was monthly (see Section 6.2.7).

Table 4.8 Equipment blanks taken in 2017

Date Sampled Equipment

9-Jan-17 KEM-1B

9-Feb-17 KEM-1B

6-Mar-17 KEM-1B

11-Apr-17 KEM-1B

9-May-17 KEM-1B

22-May-17 KEM-1B

1-Jun-17 KEM-1B

29-Aug-17 KEM-1B

20-Sep-17 KEM-1B

19-Oct-17 KEM-1B

21-Nov-17 KEM-1B

7-Dec-17 KEM-1B

Turbidity, total phosphorus, total aluminum, total barium, total lead, and total manganese were all above detection limits in one or more of the equipment blanks (Table 10, Appendix D). A summary of results for the KEM1 blanks that are greater than five times the detection limit is provided in Table 4.9.

Table 4.9 Summary of KEM1 blank results that are 5x detection limit

Date Sampled Parameter Detection Limit Result

6-Mar-17 Total Phosphorus (mg/L) 0.0020 0.0474

22-May-17 Total Lead (mg/L) 0.000050 0.000379

19-Oct-17 Total Barium (mg/L) 0.000050 0.000284

07-Dec-17 Total Lead (mg/L) 0.000050 0.00111

The equipment blank parameters that are above detection limit are rechecked by ALS laboratory. A code is associated with the parameters in the results spreadsheet to indicate that the result was rechecked and verified. The elevated total phosphorus result stemmed from the cleaning agent that contained phosphate; it has subsequently been changed to a phosphate-free detergent. Investigations for total lead and barium results are on-going.


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4.5 Data Quality Review and Data Management

A data quality review was conducted for results, including screening of laboratory QA/QC data, sample integrity issues, detection limits achieved, and metadata accuracy, as well as potential outliers/extreme values. This information was catalogued in the MPMC sample tracking spreadsheets described in Section 4.4.

MPMC uses MonitorPro (MP-5 database) by EHS Data Limited for data management. water, soil, sediment, and tissue chemistry data as well as weather station downloads were uploaded into the MP-5 database using files generated by the analytical laboratory. Accompanying field data was manually entered and uploaded into the MP-5 database. Original laboratory-produced results files are filed on the MPMC network according to location, and date, and are linked to the data stored in the MP-5 database. Sample names, dates, and times are cross-referenced with the MPMC sample tracking sheet before final upload to the database and field data undergo a QC screening prior to upload. Parameter restrictions are in place in the MP-5 database to reduce the likelihood of a typographical or laboratory reporting error being uploaded. Any errors identified by the MP-5 database underwent further audit before final acceptance.

Non-chemistry data, including toxicity testing results, benthic invertebrate and plankton taxonomy data, and hydrology data (logger downloads and FlowTracker exports) are filed according to year and site on the MPMC network.

4.5.1 Rating Curve Equation

Stage-discharge rating curves were developed for the hydrometric stations by relating manual water level and stream discharge measurements acquired by MPMC (velocity based measurements using a SonTek FlowTracker) and WaterSmith (dry salt slug injection tracer method [Hudson and Fraser, 2005]). The rating curves were fit statistically [R Development Core Team, 2010] using a nonlinear least-squares regression model of the following generic form:

Q = 10(a + b log10(H - c))

where 𝑄𝑄 is the discharge, m3/s, 𝐻𝐻 is stage (m), a, b, and c are regression coefficients.

Vented pressure transducers (model INW PT2x) were installed at various sites to continuously monitor water levels at 10 minute intervals during non-freezing months. According to the manuals, INW PT2x sensors maintain a sensor accuracy of ±0.25% (Seametrics 2016). A linear relation was developed between the automatically recorded pressure and the manual staff gauge readings at each station. Stage values estimated from the pressure readings using the stage-pressure rating relation can then be substituted into


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the rating curve equation to estimate discharge at a 10 minute interval throughout the monitoring season. Any estimation above the highest measured discharge is considered an extrapolation.

Statistical analysis of the manual gauge readings are reported in Sections 7.6 and 8.3 and in Appendix K.

As required by Section 3.4 of the EMA Permit 11678, calibration measurements (taken by a dry salt slug injection tracer method) and benchmarking surveys of hydrological stations were conducted by a qualified professional, in this instance, WaterSmith, from August 29-30, 2017. Details of the site visit will be reported in in Sections 7.6 and 8.3.

Routine monitoring incorporates inspections of equipment, including stilling wells and loggers (e.g., to identify sedimentation inside the stilling well, debris build up in logger ports). QA/QC of all collected data was completed to identify potential station changes or issues like spurious errors and drifts in the automated data. This process included comparisons with previously collected data.


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5 Mine Site Environmental Monitoring

5.1 Contact Water Chemistry

Contact water sampling and analysis was conducted as outlined in sub-Sections 2.4 and 3.2 of EMA Permit 11678 (Appendix A). Surface sampling is outlined as per Section 4.1 in the 2016 CEMP (Appendix A). Refer to Section 4 of this report for a discussion of field sampling equipment and methodology.

This section contains data for effluent site with a prefix letter “E”. Sample site and frequency are summarized in Table 5.1. Sample locations are shown in Appendix B. The effluent site listed in this section, E11, is contained within the site and treated and discharged as per sub-Section 1.2 of the September 19, 2016 amended EMA Permit 11678 (Appendix A). Direct discharge from the Springer Pit to the WTP ceased after March 30, 2017. Approval to cease the sampling of E11 and E11a was granted by ENV on October 26, 2017 (Appendix O). As per sub-Section 4.1.2 of the 2016 CEMP (Appendix A), legacy sites such as East and West Main Toe Drains, MESCP (E4) and CCS (E18) that no longer discharge into Hazeltine or Edney Creek have been removed. Note that E19 (PETBP), and E11a (Springer Pit Supernatant), were included as a surface contact water sites in the CEMP but will be discussed in the discharge system and monitoring section of the annual report (see Section 6). All other contact water sites that are collected under Mines Act Permit M–200 are described in Section 11.5.

Table 5.1 Sampling events in 2017 at contact water quality sites

Site Site Identifier (EMS No.)

Frequency

Permit Requirement Actual

E1a (a) E225309 Monthly 13 E11 E302090 Monthly (b) 4 (c)

(a) Deposition of tailings into TSF is ongoing; TSF supernatant being used as reclaim water as of November 8, 2016. E1 has been replaced by E1a.

(b) Monthly commencing in May 2016; samples at E11a were taken weekly when directly discharging from Springer Pit to WTP.

(c) Samples taken in January, February, September and November. No Springer Pit water was directly discharged to the WTP as of March 30, 2017.

Samples were submitted to ALS for analysis of:

• Physical parameters (pH, turbidity, TSS, total dissolved solids, and hardness); • Anions and nutrients (alkalinity, sulphate, total nitrogen, nitrate, nitrite, ammonia, chloride, fluoride,

total phosphorus, dissolved phosphorus, and ortho-phosphorus); • Organics (dissolved organic carbon); and • Total and dissolved metals (metals suite as listed in CEMP (Appendix A).


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Thirteen (13) parameters of interest (POIs) were identified in the Chemical Characterization of the Proposed Effluent for Discharge to Hazeltine Creek (Knight Piésold Ltd 2009) based on site geochemistry and historical characteristics, as well as existing and projected waste and water management practices. To monitor changes in the effluent surface water quality, in the subsequent sections, these POIs were reviewed for each water quality site over time:

• Physical Parameters: Hardness, TSS; • Anions: Chloride, sulphate; • Nutrients: Nitrate, total phosphorus; and • Metals: Dissolved aluminum, total cadmium, total copper, total molybdenum, total and dissolved

iron, total selenium.

Results for POI concentrations for the effluent sites are noted and included in tabular format in Appendix E. Note that results below method detection limit (MDL) are represented as half (0.5x) the MDL in statistical calculations and graphs.

Water quality data, including summary statistics (number, minimum, maximum, mean, standard deviations, and method detection limit) are provided in Appendix E.

5.1.1 Site E1a – Tailings Supernatant (E225309)

Tailings deposition into the TSF recommenced in June 2016. The reclaim barge (location of E1) was floating and reclaim water was being sourced by November 22, 2016, so sample collection began at this time. This location was renamed to “E1a” to reflect the deposition of tailings after the TSF embankment breach. Water quality at this location was sampled thirteen (13) times in 2017. Graphs and results for a subset of parameters only for the post-breach years, are provided in Appendix E. Notable observations in POI results are compared with data from the last five years (three years pre-breach and two years post-breach):

Hardness: A general increase in concentration occurred after tailings deposition started post-breach. The 2017 annual mean was 510 mg/L, and overall post-breach mean of 519 mg/L. The pre-breach mean was 446 mg/L. The maximum hardness post-breach has increased compared to pre-breach with concentrations of 609 mg/L and 500 mg/L respectively.

TSS: Concentrations have remained stable post and pre-breach. The 2017 annual mean was 17.7 mg/L, and overall post-breach mean of 17.8 mg/L. The pre-breach mean was 12.0 mg/L. The maximum TSS post-breach is similar to pre-breach with concentrations of 50.1 mg/L and 54.9 mg/L respectively.

Chloride: Concentrations have remained stable post and pre-breach. The 2017 annual mean was 21.6 mg/L, and overall post-breach mean of 21.1 mg/L. The pre-breach mean was 24.0 mg/L. The maximum chloride post-breach is similar to pre-breach with concentrations of 26.5 mg/L and 28.0 mg/L respectively.


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Sulphate: Concentrations have remained stable post and pre-breach. The 2017 annual mean was 613 mg/L, and overall post-breach mean of 616 mg/L. The pre-breach mean was 545 mg/L. The maximum sulphate post-breach is above pre-breach with a concentration of 596 mg/L and 675 mg/L respectively.

Nitrate: Concentrations have increased post-breach. The 2017 annual mean was 10.5 mg/L, and overall post-breach mean of 10.6 mg/L. The pre-breach mean was 6.5 mg/L. The maximum nitrate post-breach is above pre-breach with concentrations of 12.8 mg/L and 7.76 mg/L respectively.

Total phosphorus: Concentrations have remained stable post and pre-breach. The 2017 annual mean was 0.024 mg/L, and overall post-breach mean of 0.024 mg/L. The pre-breach mean was 0.014 mg/L. The maximum total phosphorus post-breach is similar to pre-breach with concentrations of 0.07 mg/L and 0.06 mg/L respectively.

Dissolved aluminum: Concentrations have remained stable post and pre-breach. The 2017 annual mean was 0.0246 mg/L, and overall post-breach mean of 0.0232 mg/L. The pre-breach mean was 0.0208 mg/L. The maximum dissolved aluminum post-breach is similar to pre-breach with concentrations of 0.0505 mg/L and 0.0521 mg/L respectively.

Total cadmium: Concentrations have remained stable post and pre-breach. The 2017 annual mean was 0.00002 mg/L, and overall post-breach mean of 0.00003 mg/L. The pre-breach mean was 0.00003 mg/L. The maximum total cadmium post-breach is equal to pre-breach with a concentration of 0.00004 mg/L. Note that the majority of results are below detection limit in pre- and post-breach sampling.

Total copper: Concentrations have increased post-breach. The 2017 annual mean was 0.019 mg/L, and overall post-breach mean of 0.02 mg/L. The pre-breach mean was 0.009 mg/L. The maximum total copper post-breach is approximately double the pre-breach concentration of 0.083 mg/L and 0.041 mg/L respectively.

Total molybdenum: Concentrations have remained stable post and pre-breach. The 2017 annual mean was 0.193 mg/L, and overall post-breach mean of 0.191 mg/L. The pre-breach mean was 0.184 mg/L. The maximum total molybdenum post-breach is similar to pre-breach with concentrations of 0.258 mg/L and 0.213 mg/L respectively.

Total iron: Concentrations have remained stable post and pre-breach. The 2017 annual mean was 0.317 mg/L, and overall post-breach mean of 0.338 mg/L. The pre-breach mean was 0.245 mg/L. The maximum total iron post-breach is similar to pre-breach with concentrations of 0.814 mg/L and 1.47 mg/L respectively.

Dissolved iron: Concentrations have remained below detection limits in pre- and post-breach results.


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Total selenium: Concentrations have remained stable post and pre-breach. The 2017 annual mean was 0.0362 mg/L, and overall post-breach mean of 0.0359 mg/L. The pre-breach mean was 0.0266 mg/L. The maximum total selenium post-breach is similar to pre-breach with concentrations of 0.0423 mg/L and 0.346 mg/L respectively.

Only three parameters have shown significant increase in concentration after post-breach deposition of tailings commenced. Hardness, nitrate and total copper have shown a general increasing trend, with total copper and nitrate almost doubling in concentrations in post-breach era. Monthly sampling is on going at this site, and tailings water is discharged through the WTP via the PETBP.

5.1.2 Site E11 – Springer Pit Sump (E302090)

The Springer Pit Sump (E11) was sampled four (4) times in 2017. Samples for E11 in 2017 are not representative of the pit lake water quality, rather of runoff water coming down the ramp to the pit. Therefore no further discussion will be included in this section. Results are provided in Appendix E.

5.2 Seep Sampling

Seep sampling is conducted under Mines Act Permit M–200 and is summarized in Section 11.5.

5.3 Groundwater Monitoring

5.3.1 Site Groundwater Program

MPMC contracted Golder as the QP, to present and interpret the data from the 2017 groundwater monitoring program. A summary of conclusions and recommendations from Golder’s report (Appendix F) is as follows.

Based on the results of this monitoring program, the following conclusions are provided:

• Groundwater levels at GW15-1(a,b), GW15-2(a,b) and GW12-2(a,b) (located on the west side of the minesite) displayed similar trends to surface water elevations within Springer Pit, and appear to be influenced from the filling and emptying of the pit. When these groundwater elevations (particularly those at GW12-2(a,b) and GW15-2(a,b) are greater than the surface water elevation within the pit, it is inferred that a groundwater divide is present between Springer Pit and Bootjack lake (in the area of these monitoring wells). This groundwater divide results in groundwater flowing from these monitoring wells towards to east, to Springer Pit, and also towards the west to Bootjack Lake.

• Based on the 2017 groundwater level elevations and the water level elevations in Springer Pit, it can be inferred that groundwater leakage from Springer Pit to Bootjack Lake did not occur.


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• Significant changes to groundwater quality have not been identified in 2017. Slightly increasing POI concentration trends at the following downgradient locations could be indicative of the effects of seepage from some mine facilities:

o Hardness at GW12-2b, GW96-7, GW11-1a, GW00-1b, and GW96-4b o Sulphate at GW12-1b, GW12-2(a,b), GW15-2b, 95R5-1, GW05-1, GW96-4b, GW96-2b, and

GW96-3a o Nitrate at GW15-2b, GW12-1b, GW11-1a, GW05-1, and GW12-4b o Arsenic at GW15-2a, GW12-3b, 95R-5, and GW96-3a o Molybdenum at GW15-2a, GW12-4a, and GW96-3a o Copper at GW12-5b and GW00-1b o Selenium at GW05-1

Based on the results of the 2017 annual groundwater monitoring report, and as previously noted in Golder’s August 16, 2017 technical memorandum summarizing the results of previous hydrogeological assessments conducted in association with Springer and Cariboo Pits (Golder 2017), the following recommendations are provided:

• Continue the groundwater level and quality monitoring program at the mine site. This includes measuring the depth to groundwater at the various on-site monitoring wells a minimum of once per year on the same day.

• No water levels were measured at GW14-1 due to the use of the well as a pumping well. If possible, a depth to groundwater, during both pumping and non-pumping conditions, should be measured a minimum of once per year, and specifically, during the one day when the depth to water is measured at all other wells on one given day.

• Although Golder had previously recommended to reduce the frequency of water quality monitoring at GW12-2 (a,b), GW15-1 (a,b) and GW15-2 (a,b) from monthly to quarterly, it is recommended that an additional year of quarterly monitoring be conducted, as some increasing (albeit slight) trends for POIs at these locations were noted.

• An additional year of groundwater quality monitoring at the 2016 well series on a quarterly basis should be conducted, after which the frequency should be re-evaluated.

• Following the full dewatering of Springer Pit (anticipated in 2018), a hydrogeological report summarizing the characterization of the groundwater regime in the area between the Springer and Cariboo Pits and Bootjack Lake should be issued. The hydrogeological assessment should include information collected since 2014, over the period of pit lake filling and initial dewatering. This will allow for the refinement of hydrogeological conditions for a fully developed pit lake that is required in support of mine closure planning.


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• The groundwater model previously developed for the area between Springer and Cariboo Pits and Bootjack Lake (Golder, 2016b) should be recalibrated using current groundwater and surface water elevations prior to mine closure.

The next groundwater monitoring program review will be completed by March 31, 2019 as required by EMA Permit 11678.

5.3.2 Groundwater Management

MPMC retained Golder to provide an Adaptive Management Plan (AMP) in response to meetings held in 2017 with ENV regarding potential exfiltration from Springer Pit toward Bootjack Lake. The focus of the AMP is to identify, manage, and learn how to reduce uncertainty with respect to groundwater seepage from the Springer Pit to the receiving environment (ie. Bootjack Lake) during operations and closure. Water chemistry and hydraulic head pressures in the groundwater wells near the Springer Pit will be monitored on an ongoing basis and the AMP will be updated annually. The most recent version of the AMP is located in Appendix F.

5.4 Climate

MPMC’s EMA Permit 11678, Section 3.6 (Appendix A) requires the collection of detailed meteorology data. The objective of this data collection program is to provide site-specific precipitation and evaporation data for use in water balance calculations and hydrological predictions. Mount Polley Mine maintains two (2) automated HOBO weather stations. These stations monitor temperature, rainfall, solar radiation, relative humidity, wind direction, wind speed, and wind gust speed. Weather Station #1 is located approximately one (1) km southeast of Polley Mountain and was installed in September 2012. Weather Station #2 is located northeast of the TSF (between the Rock Quarry and Biosolids Storage Facility) and was installed in November 2012. Due to equipment and battery issues, only partial data is available from Station #2 for May and October. Station #1 has only partial rain data due to a sensor error for July. There were no periods in 2017 when both stations were not logging data. A summary of the monthly site precipitation, evaporation, and temperature data collected in 2017 is provided in Table 5.2.

Evaporation is calculated by using the Penman-Monteith equation using the WaSIM software developed by Cranfield University. Snowfall measurements are based on monthly snowpack testing done at multiple locations across the site. These measurements are taken at the end of every month, as well as between melting and snowfall events, if forecasted.

Table 5.2 Mount Polley Mine monthly precipitation, evaporation, and temperature data in 2017.


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Month Monthly

Precipitation as Rain (mm)

Monthly Snowpack (mm Snow Water

Equivalent)

Evaporation (mm)

Average Temperature

(°C)

Maximum Temperature

(°C)

Minimum Temperature

(°C)

January 0 130 5 -7.4 5.9 -23.5 February 0 135 14 -7.1 9.4 -24.7 March 0 75 39 -1.8 9.1 -16.3 April 46.4 0 70 3.0 13.8 -0.5 May 36.3 0 105 9.9 27.5 -1.3 June 37.8 0 158 13.4 30.3 2.8 July 8.1 0 166 16.5 31.0 5.1 August 20.0 0 140 17.7 32.2 4.5 September 33.5 0 69 11.3 28.8 -1.1 October 44.4 0 24 3.0 16.4 -4.0 November 3.2 20 11 -2.1 8.6 -17.3 December 0.0 58 1 -8.4 3.8 -25.7

5.4.1 Wind Monitoring

It was confirmed by the database company (EHS Data) that previous wind data presented here before the 2015 Annual Environmental and Reclamation Report (MPMC, 2015b) was an inaccurate representation of site conditions. The figures presented below are an accurate representation of the 2013 to 2017 data. Figure 5.1 shows wind data collected by the site weather stations in 2017, and data collected on site since 2013. Data collected in 2017 are consistent with data collected in the past three years. High speed winds are typically observed from the northwest, but in general, there is no dominant wind direction.

Figure 5.1 Mount Polley Mine wind data for 2017 (left), and for 2013-2017 for Weather Station #1 (centre) and Weather Station #2 (right)

5.4.2 Temperature

In 2017, the lowest monthly mean temperature was -8.4 °C recorded in December, and the highest monthly


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mean temperature was 17.7 °C recorded in August. Monthly mean temperatures were warmer than average in May, June, July, August, and September when compared to site data collected since 1995. Figure 5.2 presents a comparison of 2017 maximum, mean, and minimum monthly temperatures with average monthly temperature data (based on data collected at Mount Polley Mine since 1995). This data is shown in tabular form in Table 5.2.

Figure 5.2 Maximum, mean and minimum monthly temperature data for Mount Polley Mine (2017 versus average)

5.4.3 Precipitation

In 2017, 442 millimetres (mm) of precipitation were recorded: 230 mm as rain and 212 mm as snow water equivalent (SWE). This is below the average annual precipitation of 630 mm, with both rainfall and snowfall below their respective annual averages. The 2017 snowpack peaked in February, and was below average (80% of average). Total rainfall was lower compared to monthly averages for all months, with the most rain falling in April (46 mm) and September (44 mm). The driest non-freezing month was July, with 8.1 mm of rain recorded. Precipitation data by month are presented in Table 5.2, Figure 5.3, and Figure 5.4. All precipitation averages are calculated based on data collected at the Mount Polley Mine site since 1995.

-30.0

-20.0

-10.0

0.0

10.0

20.0

30.0

40.0

Tem

pera

ture

(°C)

Monthly Temperatures (°C)

Average Mean Temp 2017 Mean Temp Average Max Temp

2017 Max Temp Average Min Temp 2017 Min Temp


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Figure 5.3 Monthly rainfall at Mount Polley Mine (2017 versus average)

Figure 5.4 Monthly snowpack at Mount Polley Mine (2017 versus average)

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

Rain

fall

(mm

)Precipitation as Rainfall (mm)

Average 2017

0

20

40

60

80

100

120

140

160

180

January February March April November December

Snow

Wat

er E

quiv

alen

t (m

m)

Snowpack (mm)

Average 2017


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5.4.4 Evaporation

Total open water evaporation in 2017 was calculated to be 801 mm. July experienced the greatest amount of evaporation at 166 mm. Monthly evaporation data are presented in Table 5.2. Figure 5.5 presents monthly comparisons of precipitation and evaporation for 2017. All evaporation averages are calculated based on data collected at the Mount Polley Mine site since 1995

Figure 5.5 Mount Polley Mine monthly precipitation and evaporation in 2017.

0

20

40

60

80

100

120

140

160

180

Prec

ipita

tion/

Evap

orat

ion

(mm

)

2017 Precipitation & Evaporation

Precipitation (Snow + Rain) Evaporation


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6 Discharge System and Monitoring

The WTP is a Veolia ACTIFLO® system, which was commissioned in October 2015. Discharge began on December 1, 2015, and continued throughout 2017. The total discharge in 2017 was 2,019,650 m3. The 2016 Annual Discharge Plan (MPMC, 2016c) was prepared and submitted to ENV on June 16, 2016; it was approved on December 20, 2016. The 2017 Annual Discharge Plan (MPMC, 2017e) was originally submitted to ENV on April 14, 2017 and is still under review.

6.1 Discharge System

Based on site water management objectives, site contact water is either pumped directly to the TSF or reports to the gravity-driven sections of the West Ditch or Long Ditch, the latter two of which both flow to the CCS. Water in the CCS is currently allowed to overflow to the PETBP where it is pumped to the WTP. Pumping infrastructure also exists at the CCS such that it can be directed to the TSF. Water from the TSF is primarily pumped to the Mill via the Booster Station to meet process requirements, but can also be diverted to the CCS from which it can flow to the WTP via the PETBP. The WTP sources water from the PETBP. When discharging in 2017, effluent was conveyed from the WTP to the Hazeltine Creek Channel; this water then flowed from the channel to Quesnel Lake through a pair of diffusers. Discharge to the Hazeltine Creek channel ceased September 30, 2017.

6.1.1 Treatment Works and Source Control Optimization

MPMC was required to assess and optimise the existing treatment process and works on a regular basis in the amended April 7, 2017 EMA Permit 11678. A series of deliverables established under Section 2.9 of EMA Permit 11678:

1) Final Assessment Report implementing an improved copper removal process 2) Initial Optimization Plan and Optimization Plan Updates 3) Explosive and Nitrogen Management Plan

The first deliverable examined the copper removal process in the WTP, and recommended continued optimization of the WTP for targeted copper treatments. This report also identified potential upgrades to site works (eg. ditches and sumps) to decrease erosion potential and reduce the TSS and associated metal-bearing particulate content of WTP influent (MPMC, 2017f).

The second deliverable addressed the recommendations from a final assessment report. Optimization for copper treatment at the WTP was continued based on findings from bench-scale testing. Maintenance and surveillance of on-site water management systems was continued part of operations at the Mine as per OMS and Sediment and Erosion Control Plan (MPMC, 2017g).

The Explosive and Nitrogen Management Plan outlined the sources of nitrogen in the WTP influent and


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associated mitigation practices. MPMC implements a blasting quality control program that follows the drill/blast process from design through implementation and into review. Environmental monitoring and sampling of site contact water and seep and drainage water are conducted and managed under the 2016 CEMP (Appendix A), (MPMC, 2017h). Discharge limits of ammonia, nitrate and nitrite are included in EMA Permit 11678 found in Appendix A.

6.1.2 WTP Operations

During treatment, the feed water of the WTP undergoes suspended solids removal using Veolia ACTIFLO® water treatment technology prior to discharge. The WTP doses the raw water with coagulant to a tank where a polymer is injected to create floc particles. Microsand is added to ballast the flocculants, which move on to another tank that allows them to swell and mature. The water flows to the next stage, which uses lamella to clarify the water and promote fast settling of the microsand ballasted sludge. The clarified water is discharged and the sludge is separated from the microsand, which is reused. An on-line turbidity meter measures the turbidity every ten seconds and calculates the TSS using a calibrated factor based on a site-specific correlation between turbidity and TSS. If an on-line TSS measurement is above 11 mg/L for 10 minutes, or over 12 mg/L instantaneously, an alarm sounds to alert the operator and the WTP automatically goes into recirculation mode and ceases discharge.

In lower Hazeltine Creek, the water was transferred into Quesnel Lake from the Hazeltine Creek upper sedimentation pond via intake structures which feed two pipelines with diffusers (two sedimentation ponds were constructed in lower Hazeltine Creek following the 2014 TSF embankment breach to reduce suspended solids loadings into Quesnel Lake). The water discharge had flow rates of up to 0.3 m3/s, was continuous (year-round), and be operational for a maximum of two years, during which time the long-term strategy is planned to be implemented, as described in Section 3.1.6.

In 2017, the WTP ran continuously from January 1 to March 30, 2017. As Hazeltine Creek was experiencing naturally high flows at the end of March, the WTP was shut down to prevent a discharge flow exceedance at the outlet to Quesnel Lake. A requirement for additional toxicity testing as outlined in Section 1.2.4 and 1.2.6 of the newly amended EMA Permit 11678 from April 7, 2017, delayed the re-start of discharge from the WTP, however this testing was completed with successful results and was approved by the Director on May 16, 2017. Discharge did not restart until June 6, 2017 as further discussion with ENV was required to ensure that all compliance requirements were achievable. The WTP was again shut down on July 10, 2017 due to the surrounding wildfires in the Cariboo area and the inability to ship samples because of road closures and evacuation of the mine site. Discharge recommenced on September 18, 2017 and was once again shut down on September 30, 2017 to facilitate construction of the direct discharge pipeline. There was no discharge for the remainder of 2017. Total treated effluent discharged in 2017 was 2,019,650 m3.

6.1.3 Outfall and Pipeline Commissioning and Inspection

As required by in Section 3.5 of EMA Permit 11678 (Appendix A), routine visual inspection of the outfall into


50

Quesnel Lake, along with the pipeline, must be conducted. MPMC conducts routine inspections and maintains records of these routine inspections.

A comprehensive inspection and testing of the outfall must be conducted by a QP annually for the first three years (2015-2017), followed by once every three years thereafter (starting with 2020). The comprehensive inspection conducted on September 6, 2017 and was submitted to ENV. There were no follow up requirements identified.

In 2017, MPMC transitioned from the short term to long-term water management plan with the construction of a pipeline to Quesnel Lake. The construction was completed on November 24, 2017 under the supervision on Golder. As required by EMA Permit 11678, a series of testing was completed prior to the authorization from ENV commence the use of the pipeline. Following the submission of the testing results report to ENV, MPMC received an email confirmation from ENV that MPMC had met the requirements of Section 3.5 and could now commence discharging from the WTP through the pipeline (Appendix O).

6.2 Discharge Monitoring

This section provides an assessment of the compliance with amended EMA Permit 11678 limits with respect to the data collected at the WTP discharge end-of-pipe site (HAD-03) and at the edge of the initial dilution zone (IDZ) site (QUL-58) in Quesnel Lake. These data were collected in accordance with the approved 2016 CEMP (Appendix A) and supporting correspondence with ENV (Appendix O). This compliance is primarily based on the permit conditions stipulated in the EMA Permit 11678 dated April 7, 2017. This section addresses the EMA Permit 11678 Section 3.9 requirements:

• (e) a summary of any non-compliance with the permit and other incidents that may have led to impacts to the receiving environment;

• (k) a comparison of monitoring data with water quality guidelines, predictions, and targets.

This discharge triggered the Metal Mine Effluent Regulations (MMER) and reporting to Environment Canada continued in 2017 as outlined in the MMER. All requirements were met with the exception of the second bi-annual chronic toxicity testing due to the shut down of the discharge. Table 6.1 outlines the number of sampling events at each site in 2017 (a map of these locations is provided in Appendix B).

Table 6.1 Sampling events in 2017 at discharge monitoring sites


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Site Name Site Identifier (EMS No.) Full Sample Suite Frequency Actual Sampling Events

E11a E305894 Weekly (a) 9

E19 E305050 Weekly (b) 28

HAD-03 E304230 Weekly (b) 25

HAC-01c E303953 Weekly (c) 10

HAC-05a E304510 Monthly 22

HAC-08 E303013 Monthly 23

HAC-10 E303010 Monthly 21

HAC-12 E304351 Weekly (b) 38

HAC-13 E304810 Weekly (b) 38

QUL-57 E304874 Weekly/Monthly (d) 0

QUL-58 E304876 Weekly/Monthly (e) 16

QUL-59 E304875 Weekly/Monthly (d) 0

QUL-2a E303020 Monthly (f) 7

QUL-18 E303019 Monthly (f) 8

QUL-120a E303022 Seasonally/Bi-annually (g) 3

QUR-11 E306454 Monthly (h) 12 (a) Established April 28, 2016 to replace E11; taken weekly until March 30, 2017 when direct discharge from Springer

Pit to WTP ceased.

(b) When discharging.

(c) As of November 21, 2017, Hazeltine Creek is no longer reporting to the diffusers and HAC-12 no longer represents the outlet to Quesnel Lake; HAC-12 has been replaced by HAC-01c.

(d) Reduced to monthly profiles only based on the recommendations provided in Golder’s Review of Monitoring Frequency in Quesnel Lake (Golder, 2016a). Samples collected only when discharging.

(e) Weekly during spring and fall turnover; monthly all other times of the year. This was reduced in 2016 based on the recommendations provided in Golder’s Review of Monitoring Frequency in Quesnel Lake (Golder, 2016a).

(f) Monthly between spring and fall turnover; twice during winter (if weather permits).

(g) Seasonally (four times per year) as per the 2016 CEMP; weather conditions did not allow for sampling in fall or winter.

(h) Established April 6, 2016; replaced QUR-1; reduced to monthly June 1, 2016.

6.2.1 Permit Compliance

The EMA Permit 11678 requires the following regulatory compliance be met:

1. Effluent chemistry data from end-of-pipe at HAD-03 (WTP outflow) must be equivalent to or less


52

than specified values in Section 1.2.3 of the Permit. The discharge characteristics must meet the limits, while discharging, for the “Edge of the Quesnel Lake Initial Dilution Zone (IDZ) in Quesnel Lake” specified in Section 1.2.3 of the EMA Permit 11678.

2. Effluent must meet the acute toxicity requirement of less than 50% mortality in 100% effluent in 96-hour rainbow trout (Oncorhynchus mykiss) and 48-hour Daphnia magna toxicity tests (EMA Permit 11678 Section 3.3 and 3.10). Intake to Secondary Discharge Point to Quesnel Lake (HAC-12) must meet the chronic toxicity requirement of less than 25% inhibition in 7-day survival and reproduction of Ceriodaphnia dubia and less than 25% non-viable embryos in 7-day early life stage (ELS) of salmonid fish (Permit Section 3.3 and 3.10). Further discussion will be presented in Section 6.4.

6.2.2 Influent Chemistry

In accordance with 2016 CEMP, E19 (WTP Feed) water samples were taken concurrently with HAD-03. The WTP monitors the influent flow rate, turbidity and temperature. Water samples were also collected at E11a (Springer Pit Pump) when Springer Pit supernatant was directly pumped to the WTP during the first quarter of 2017.

6.2.2.1 E11a – Springer Pit Pump

E11a was sampled from January 9 to March 27, 2017 as naturally high flows in Hazeltine Creek prompted the shut down of the WTP. The pipeline from Springer Pit to the WTP was disconnected before the restart of the WTP in June 2017. For the rest of 2017, Springer Pit water was collected with other contact site water in the PETBP.

6.2.2.2 E19 – Water Treatment Plant Feed

E19 represents the water entering (influent) into the WTP; the influent is pumped from the PETBP which collects the contact water from the mine site. Twenty-eight (28) samples were collected from E19 in 2017. The influent results are compared with the effluent results to gauge the efficiency of the treatment.

6.2.3 Effluent Chemistry – HAD-03

To meet the requirements of the EMA Permit 11678 and MMER requirements, water chemistry samples were collected weekly at the end-of-pipe site at the WTP outlet (site HAD-03) when discharging. This requirement was met by the collection of twenty-five (25) samples at HAD-03 in 2017. Note, there was no discharge from March 30 to June 5, from July 10 to September 19, and from September 30 to December 31, 2017. All parameters were at or below the concentrations limits in Section 1.2.3 of the EMA Permit 11678 with the exception of one parameter (details in Section 6.2.3.1).

Compared to 2016, there were no exceedances of total copper. From January to March 2017, the permit


53

limits from the amended September 19, 2016 EMA Permit 11678 were in effect. For that period, the total copper limit was 0.012 mg/L. With the amended EMA Permit 11678 from April 7, 2017, the permit limit for total copper was revised to 0.033 mg/L. The maximum result for total copper at HAD-03 in 2017 was 0.011 mg/L in June; the annual average was 0.007 mg/L. Results for the influent and effluent are shown below and for clarity purposes, only the updated (April 7, 2017 amendment) permit limit is shown in Figure 6.1.

Figure 6.1 Total copper concentrations in influent (E19) and effluent (HAD-03) in 2017.

Compared to 2016, there were no exceedances of TSS. The permit limit for TSS has been consistent between the two most recent EMA Permit 11678 amendments. The maximum total TSS limit must be equivalent to or less than 30 mg/L with a monthly average equivalent to or less than 15 mg/L. The maximum result for TSS at HAD-03 in 2017 was 11.1 mg/L in March; the annual average was 5.59 mg/L. Results for influent (E19) and effluent (HAD-03) TSS are shown in Figure 6.2.


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Figure 6.2 Total suspended solids concentrations in influent (E19) and effluent (HAD-03) in 2017.

6.2.3.1 Permit Limit Exceedance Event

Total zinc from the January 3, 2017 sampling event at HAD-03 resulted in a concentration of 0.012 mg/L which was above the permit limit of 0.0083 mg/L (from the September 19, 2016 amended EMA Permit 11678). It was noted that the influent (E19) concentration was 0.0031 mg/L. MPMC notified the Director of the possible exceedance and to justify not shutting the WTP but instead, reducing the flow due to the extreme freezing temperatures (See Appendix O).

Further investigation included re-analysis of the total metal sample bottle, which confirmed the original report; and analysis from the raw (non-preserved) water sample bottle, which returned zinc results below detection limit. Samples collected on January 9 and 10, 2017 also resulted in total zinc below detection limit. Upon reviewing the investigation, the total zinc result above the discharge limit was likely due to sample bottle contamination. Proper handling procedures were reviewed by the MPMC Environmental Department field crews to avoid any possible contamination of sampling equipment during future sampling events.

There were no other permit limit exceedances in 2017 at HAD-03.


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6.2.4 Hazeltine Creek

Water quality was monitored weekly and monthly at various sites throughout Hazeltine Creek when discharge occurred in 2017 in accordance with the 2016 CEMP (see Table 6.1). Fish continued to be excluded by physical barriers at upper and lower Hazeltine Creek as the creek underwent construction and remediation work in 2017.

Water quality data for Hazeltine Creek are included in Appendix E. Under the EMA Permit 11678, it is not considered a receiving environment, therefore is not discussed in depth, except for any BC Water Quality Guideline (BCWQG) for aquatic life exceedances at HAC-12. Thirteen (13) acute (see Table 6.2) and fifty-six (56) chronic (see Table 6.3) BCWQG exceedances occurred at HAC-12 in 2017. More details on water quality in Hazeltine Creek from 2014 to 2016 are presented in the HHERA (MPMC, 2017c) and ERA (MPMC, 2017d).

Table 6.2 Summary of acute BCWQG for aquatic life exceedances for aquatic life at HAC-12.

Site Parameter Results Acute BCWQG (mg/L)

HAC-12 Dissolved aluminum 5 exceedances 0.1

Total copper 5 exceedances 0.012-0.059(a) Total iron 3 exceedances 1.0

Table 6.3 Summary of chronic BCWQG for aquatic life at HAC-12. Note that this only applies during periods where five (5) samples were collected within 30 days.

Site Parameter Results Chronic BCWQG (mg/L)

HAC-12

Dissolved aluminum 17 exceedances 0.05 mg/L Total copper 3 exceedances 0.012-0.059 (a)

Total chromium 1 exceedances 0.001 mg/L (b) Total selenium 5 exceedance 0.002 mg/L

TSS 13 exceedances 5 mg/L change from background in 30 days

Turbidity 17 exceedances 2 NTU change from background in 30 days

(a) Hardness dependent copper guideline; range given is based on hardness range at each site, when available. (b) Based on the BC working water quality guidelines (BCWWQG) for Chromium (Cr(VI)).

Dissolved aluminum: There were five (5) acute BCWQG for aquatic life exceedances in 2017. These occurred during periods of effluent discharge (two in March and June, and once in July). The exceedances appear to be individual events as discharge was continuous from January to March and throughout June to mid-July. The maximum result was 0.152 mg/L in March and an annual average of 0.053 mg/L. There were seventeen (17) chronic BCWQG for aquatic life exceedances in 2017. Twelve (12) of these exceedances spanned from February to April, another four (4) from June to July and one in September. Most of these exceedances occurred during periods of discharge; note that discharge ceased on March 30, and chronic


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exceedances still occurred in April.

Total copper: There were five (5) exceedances of the acute BCWQG for aquatic life in 2017. All except one occurred during periods of no effluent discharge. Four out of the five exceedances occurred in April during freshet when the Polley Lake weir was open. One exceedance occurred in January when discharge occurred. The maximum result was 0.287 mg/L in April, with an annual average hardness of 240 mg/L and annual average total copper result of 0.012 mg/L. There were three (3) chronic exceedances in January, April and May ranging from 0.012 to 0.024 mg/L.

Total iron: There were three (3) acute exceedances of the BCWQG for aquatic life exceedances in 2017. Two out of the three occurred in April, during freshet when the Polley Lake weir was open. The maximum result was 1.27 mg/L in October; substantial rainfall occurred during the day and the days prior to this sampling event. The in-situ turbidity was elevated in mid and lower Hazeltine Creek compared to the upper sites leading to the theory that some sloughing may have been the cause of this elevated result. The annual average of total iron was 0.313 mg/L.

Total chromium: There was one chronic BCWQG for aquatic life exceedance in 2017. The average total chromium result in April was 0.0014 mg/L. No discharge occurred in April due to freshet and the opening of the Polley Lake weir. The annual average total chromium was 0.0011 mg/L; note that twenty-three (23) out of thirty-three (33) results were below detection limit.

Total selenium: There were five (5) chronic BCWQG for aquatic life exceedances in 2017. Exceedances occurred from January to March and in June and October. These exceedances occurred during periods of discharge, however total selenium has historically been elevated in Hazeltine Creek (details on water quality in Hazeltine Creek are presented in the HHERA (MPMC, 2017c) and ERA (MPMC, 2017d). The annual average total selenium was 0.008 mg/L with a maximum result of 0.033 mg/L in September.

TSS: There were thirteen (13) chronic BCWQG for aquatic life exceedances in 2017. Exceedances occurred in January, from April to June, and in October. Natural environmental factors were the cause of the majority of these exceedances: in January, sampling occurred through the ice, which can stir up material; freshet occurred in April, with residual effects seen in May; and heavy rainfall in October appeared to result in an increase in suspended material. Water levels were low in June; therefore, some particles may have been mobilized and collected during sampling. The annual average was 6.4 mg/L with a maximum result of 20.9 mg/L in April.

Turbidity: There were seventeen (17) chronic BCWQG for aquatic life exceedances in 2017. Exceedances occurred in January, from April to May, August to September and in October. Natural environmental factors were the cause of the majority of these exceedances: in January, sampling occurred through the ice, which can stir up material; freshet occurred in April, with residual effects seen in May; and heavy rainfall in October appeared to trigger an increase in turbidity. Water levels in August and September were extremely low


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therefore, some particles may have been mobilized and collected during sampling. The annual average was 4.6 NTU with a maximum result of 24.8 NTU in October.

6.2.5 Plume Dispersion Model

Tetra Tech EBA Inc. (Tetra Tech EBA) was retained by MPMC to assess the long-term and far-field influence of effluent discharge from the diffusers in Quesnel Lake (see Section 6.1) in 2016. Tetra Tech EBA applied the existing hydrodynamic model of Quesnel Lake to simulate effluent concentrations throughout the lake as a result of the discharge. After the simulations were completed, MPMC requested advice with respect to the likely position of the effluent plume by month, to support monitoring in the field (Tetra Tech EBA, 2016). In 2017, Tetra Tech EBA was retained to determine the relationship between the volumetric dilution by a dilution test and dilution calculated from observed specific conductivity from limnological profiles in Quesnel Lake. The results improved the confidence of the estimated dilution factor applied to the profiles. Tetra Tech EBA ran the near-field model to discuss the plume width and dilution and concluded that there was only a 3% chance of detecting the plume at the IDZ. In addition, the field models suggest the plume concentrations are generally less than 1% at the IDZ (see Appendix I).

6.2.6 Receiving Environment Chemistry – Quesnel Lake

The receiving environment for the water discharge plan is Quesnel Lake and the downstream in upper Quesnel River. In accordance with the 2016 CEMP, (Table 6.1), monitoring at the edge of the IDZ in Quesnel Lake occurred monthly, when treated effluent was discharging in 2017, with intensive sampling conducted during overturn periods.

In-situ limnological profiles, secchi measurement (Section 8.6.2) and grab samples were collected for water chemistry at the inferred centerline of the effluent plume (when discharging) at the compliance site QUL-58 (when weather conditions were safe). A reasonable amount of effort was spent looking for the discharge plume by observing any visibly obvious higher specific conductivity levels using a profiler. If the plume was detected, grab samples were taken at surface, 5m above the plume, middle of plume, 5m below the plume, and bottom, with additional profiling at supplemental stations, QUL-57 and QUL-59, located at the edge of the IDZ, 25m on either side of QUL-58 (plume centerline) at the edge of the IDZ. If the plume could not be detected, then sampling occurred at the default QUL-58 site at the surface, bottom, mid-depth (if no thermocline) or 1m above and below the thermocline (if present).

In 2017, there were sixteen (16) sampling events at edge of the IDZ (QUL-58). Five (5) of those events occurred when the treated effluent was discharging (Table 6.4). The plume was not detected during the investigations by the field crew along the IDZ in 2017, when the WTP was discharging treated effluent.

Table 6.4 Effluent discharge condition during IDZ sampling at QUL-58


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Date sampled Treated effluent condition 2-Feb-17 Discharging 6-Mar-17 Discharging 10-Apr-17 Not discharging 9-May-17 Not discharging 15-May-17 Not discharging 22-May-17 Not discharging 29-May-17 Not discharging 5-Jun-17 Not discharging 12-Jun-17 Discharging 19-Jun-17 Discharging 27-Jun-17 Discharging 22-Aug-17 Not discharging 1-Oct-17 Not discharging 26-Oct-17 Not discharging 20-Nov-17 Not discharging 7-Dec-17 Not discharging

In addition to the field investigation, MPMC retained Tetra Tech EBA to develop near-field models to predict the plume direction and depth using the specific conductivity from the limnological profiles from Quesnel Lake from 2017 (Section 6.2.5). In the Quesnel Lake Monitoring: Summary of 2017 Quarterly Reviews (Appendix I), Tetra Tech EBA identified nine (9) possible plume signatures at certain sites along Quesnel Lake. Confidence levels considered as ‘High’ signify that according to the model, there is a ‘High’ certainty that the plume was detected. On only two (2) occasions in June was the plume detected when discharge was occurring and both were at QUL-58; otherwise, all other seven (7) ‘High’ confidence levels occurred when there was no discharge. As explained the Tetra Tech EBA memo, the ‘High’ confidence of plume detection at further sites (QUL-18 and QUL-2a in April and QUL-ZOO-1 and QUL-ZOO-7 in August) may be influenced from seasonal trends and other sources ie. seiche events or higher conductivity river water.

6.2.6.1 Permit Limits at the edge of Quesnel Lake IDZ

As of April 7, 2017, the amended EMA Permit 11678 included compliance limits at the edge of the Quesnel Lake IDZ. All parameters met or were below the concentrations limits in Section 1.2.3 of the EMA Permit 11678 (see Appendix H).

Total copper results for the edge of the Quesnel Lake IDZ (QUL-58) are shown below in Figure 6.3. The annual total average of total copper at the IDZ in 2017 was 0.0011 mg/L. The maximum total copper concentration (when the WTP was discharging) was 0.0021 mg/L above the thermocline at QUL-58 in March; the maximum total copper concentration (when the WTP was not discharging) was 0.0020 mg/L in December at the surface of QUL-58. Note that the maximum results are similar when the WTP was discharging and not discharging. As there are many inputs into Quesnel Lake, it is hard to pinpoint exactly


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which sources are contributing to the total copper results as the discharge is not the sole contributing factor.

Note: AT = above thermocline, B = bottom, BT = below thermocline, S = surface Figure 6.3 Total copper concentrations at the edge of the IDZ (QUL-58) in 2017.

6.2.6.2 BCWQG at the edge of Quesnel Lake IDZ

Short-term maximum and long-term average BC WQG for aquatic life concentrations were compared with the water chemistry data from QUL-58. These limits are not considered compliance as MPMC is regulated with EMA Permit 11678 requirements at the IDZ (see Section 6.2.6.1). Total copper (see Figure 6.4) and other parameters for the BC WQG for aquatic life guidelines were met (with the exception of total phosphorus).

Note that samples were taken monthly at QUL-58, with bi-annual intensive sampling during spring and fall turnover (dependent on weather conditions and safety). As summarized in Table 6.4, intensive sampling occurred during May and June (ie. five (5) samples in thirty (30) days) which can be compared to the chronic total copper guideline (see Figure 6.4). The data in Figure 6.4 is an average concentration of all depths at QUL-58 for clarity purposes. All other data points are presented for screening purposes only. Note that all concentrations from QUL-58 are below the short term maximum BC WQG for total copper.


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Figure 6.4 Short and long term BCWQG for aquatic life total copper concentrations at QUL-58 in 2017 (depths averaged).

Historically, total phosphorus has not met the BCWQG, and it continued to not fall with in the range of 0.005 mg/L to 0.015 mg/L in 2017. The monthly mean results range from 0.0010 to 0.0035 mg/L, which are below the minimum limit of 0.005 mg/L for aquatic life – lakes (where salmonids are predominant fish species). This is expected as Quesnel Lake is regarded as an oligotrophic water body.

Total phosphorus exceeded the BCWQG maximum limit of 0.015 mg/L during the March 6, 2017 sampling event at depths above and below the thermocline and at bottom, but not at surface. The surface sample was not collected using the Kemmerer sampler, and was well below the BCWQG for phosphorus. An investigation into the cause of these elevated results revealed that the samples were likely contaminated by the cleaning product used on the sampling equipment (Kemmerer, KEM-1b), which contained phosphate. The cleaning agent was changed to a new phosphate-free product. QUL-58 was re-sampled and the total phosphorus results were below the BCWQG. ENV was notified of this contamination via email. The correspondence resulted in agreement with the findings from the investigation and the discharge was allowed to continue (see Appendix O).


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6.2.7 Receiving Environment Chemistry – Quesnel River

Quesnel River, site QUR-11, is monitored and sampled monthly by MPMC as a downstream site in the receiving environment. Grab samples and in-situ parameters are collected off the Likely Bridge using the Kemmerer sampler. The water chemistry results are compared to the BCWQG for aquatic life and all guidelines were met at QUR-11 in 2017.

MPMC provides funding for a joint federal and provincial water quality monitoring site that is monitored at this same location. This sample is currently collected monthly and is generally off-set from MPMC monitoring by two weeks. The data from the government sample is available on-line.

6.3 Discharge Toxicity Testing Results

As per Section 1.2.4 of the amended EMA Permit 11678 issued on April 7, 2017, the discharge was subject to “Interim” concentrations until acute toxicity testing program on the final effluent concentrations was completed. The toxicity tests were successful (acutely non-toxic); and the ‘Final’ discharge limits were subsequent applied. Discharge from the WTP commenced and toxicity test sampling occurred as required by EMA Permit 11678 and MMER in 2017 (Table 6.5)

Table 6.5 Toxicity sampling events in 2017 at discharge and monitoring sites

Site Name

Site Identifier (EMS No.) Test Type Frequency Actual Sampling

Events

HAD-03 E304230

96-h rainbow trout LC50 Monthly 6 (b,c) 48-h D. magna LC50 Monthly 6 (b,c) 7-d C. dubia survival and reproduction Quarterly 3 (c) 7-d rainbow trout embryo-alevin Quarterly (a) 3 (c) 72-h P. subcapitata growth inhibition Bi-annually 1 (c) 7-d L. minor growth inhibition Bi-annually 1 (c)

HAC-12 E304351 7-d rainbow trout embryo-alevin Quarterly (a) 3 (c, d) 7-d C. dubia survival and reproduction Quarterly 4 (c)

(a) If test media not available at testing laboratory, 7-d rainbow trout swim-up survival and growth test was substituted

(b) Discharge only occurred in January, February, March, June, July, and September 2017. Note: Discharge was shut down on July 10, 2017 due to forest fire evacuation of the Mount Polley Mine site, therefore no acute toxicity samples could be taken.

(c) There was no discharge in quarter 4 of 2017, therefore bi-annual, quarterly and monthly toxicity samples could not be collected.

(d) There were 2 sampling events at HAC-12 in quarter 1 of 2017.


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6.3.1 Acute toxicity testing

Monthly acute toxicity testing occurred at HAD-03 throughout 2017, when the WTP was discharging (see Table 6.5). These tests were conducted on 100% (ie. full strength) treated effluent in accordance with the following standard methods as required by EMA Permit 11678 and MMER:

• 96-hour acute lethality to juvenile rainbow trout (procedures described by Environment Canada (2000a))

• 48-hour acute lethality to the water flea D. magna (procedures described by Environment Canada (2000b))

Acute toxicity tests of rainbow trout and D.magna both met the permit requirement of no acute toxicity by determining that the mortality was less than 50% in 100% effluent (results are provided in Appendix H).

6.3.2 Chronic toxicity testing

Chronic toxicity tests at HAD-03 (see Table 6.5) were conducted on 100% treated effluent according to the following standard methods as required by EMA Permit 11678 and MMER requirements:

• 7-day survival and reproduction of the water flea C. dubia (procedures described by Environment Canada (2000c))

• 7-day early life stage with salmonid (rainbow trout embryo-alevin) (procedures described by Environment Canada (1998))

• 7-day growth inhibition in the aquatic plant Lemna minor (procedures described by Environment Canada (2007b))

• 72-hour growth inhibition in the alga Pseudokirchneriella subcapitata (procedures described by Environment Canada (2007c)).

C.dubia and rainbow trout early life stage met the permit requirement of less than 25% inhibition (results are provided in Appendix H).

Effects were noted for both P.subcapitata and L.minor during the chronic toxicity testing from June 13, 2017. Stimulatory effects were observed for P.subcapitata cell yield; however, the IC25 and IC50 (%v/v) for cell yied were both >95.2%. Inhibitory effects on frond growth and dry weight of L.minor were observed with an IC25 and IC50 (%v/v) for frond growth and dry weight at 33.5% and 46.3%, and 80.8% and >97%, respectively.

Chronic toxicity testing occurred at HAC-12 on a quarterly basis (when discharging to Quesnel Lake) as required by Section 3.3 of EMA Permit 11678. These tests were conducted in accordance with the following standard methods as required by EMA Permit 11678:


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• 7-day survival and reproduction of the water flea C. dubia (procedures described by Environment Canada (2000c))

• 7-day early life stage with salmonid (rainbow trout embryo-alevin) (procedures described by Environment Canada (1998))

C.dubia and rainbow trout early life stage met the permit requirement of no chronic toxicity by determining that the inhibition of both tests was less than 25% (results are provided in Appendix H).


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7 Hazeltine Creek Aquatic Environment Monitoring

7.1 Surface Water Monitoring

Monitoring of Hazeltine Creek and its surrounding areas was completed in 2017 as per CEMP and EMA Permit 11678 requirements (see Appendix A). Hazeltine Creek sampling details are provided in Section 6.2.4 and the water quality is provided in Appendix H.

Additional monitoring was continued in the Polley Flats (area immediately west of upper Hazeltine Creek) to identify any potential influential sources seeping into Hazeltine Creek. Site POF-1 was established in 2016 and was sampled nineteen (19) times in 2017 (see Appendix E for water quality). An addition source, POF-5, was established in summer 2017 and was dry throughout the rest of the year therefore could not be sampled. Influence from these sites will be monitored by upstream and downstream samples of established sites in Hazeltine Creek in 2018.

7.2 Remediation

MPMC has been implementing a remediation strategy over the last two (2) years that resulted in the removal of tailings from the Hazeltine Creek bed and surrounding areas. In 2017, Reach 2 (from HAC-13 to HAC-05a; Appendix B) of upper Hazeltine Creek underwent channel reconstruction, fish habitat formation and floodplain contouring and planting. The fish habitat consisted of riffle-pool morphology with irregularly spaced scour pools covered by large woody debris to provide rearing, spawning and overwintering environment for rainbow trout. Terrestrial objectives included mounding and ripping as site preparation, which allowed liberation of original topsoil. Planting consisted of planting live willow and black cottonwood wattles, prickly rose, black twinberry, red osier dogwood, Sitka alder and conifers, and a native seed blend (Table 3.3). The goal of this remediation is to return the ecosystem back into its ecological homeostasis, with the planting of native species and returning fish back in the upper areas of Hazeltine Creek in 2018. The restoration work for Reach 2 was completed in November of 2017.

7.3 Periphyton

Periphyton sampling was conducted by Minnow in Hazeltine, Frypan and Edney Creeks in 2017 to meet the CEMP requirements (Appendix A). Three sites along Hazeltine Creek were sampled for chlorophyll a, ash-free dry mass, and periphyton tissue chemistry. The data and discussion of the periphyton memo by Minnow was not finalized at the time of this report submission and will be submitted separately.

7.4 Groundwater

Following the TSF embankment breach an investigation of the groundwater quality in the Hazeltine Creek riparian area was conducted in 2015 to confirm the results of the geochemistry assessment conducted by SRK Consulting Inc. (SRK, 2015a). A second groundwater assessment was completed in 2016 in support of


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the risk assessments, and in 2017, a third assessment was completed by Golder. The results and discussion reading all three assessments are included in Appendix F.

7.5 Fish Exclusion

In accordance with Section 2.6 of EMA Permit 11678 and the Hazeltine Creek Fish Exclusion and Response Plan (MPMC, 2016d), monthly visual inspections were conducted in 2017 (Table 7.3). All Inspections included the whole length of Hazeltine creek from the Polley Lake Weir to the lower sedimentation ponds near the outlet to Quesnel Lake; with the exception of the lower canyon during winter months due to safety concerns. Where fish were observed during inspections, minnow traps and/or seine nets were used in an effort to remove the fish and return them to Polley Lake in accordance with Fish Collection Permit WL17-267263. Fish were observed February 23, 2017 however no minnow traps were deployed as the Fish Collection Permit did not cover this month. Fish were observed on July 8, 2017, however no salvage was conducted as due to reduced resources and ultimately a site evacuation on July 15, 2017 due to regional forest fires.

The majority of fish were observed between the three fish fences upstream of the Polley Lake weir and immediately downstream of the weir; all other observations of fish were between the weir and the Gavin Lake Bridge. Throughout 2017, a total of eight (8) juvenile Rainbow Trout, 187 juvenile longnose suckers, and 105 juvenile/adult redside shiners were salvaged and relocated to Polley Lake.

Table 7.3 Monthly visual fish inspections results of Hazeltine Creek in 2017.

Date of Inspection Inspection Results 23-Jan-17 No fish observed

23-Feb-17 Fish observed upstream of Gavin Lake Bridge, did not have salvage permit; therefore did not complete salvage

23-Mar-17 No fish observed 15-Apr-17 No fish observed 13-May-17 No fish observed

9-Jun-17 No fish observed

8-Jul-17 Fish observed in upper portion of Reach 1 (site was evacuated on July 15; therefore no salvage was completed)

14-Aug-17 Fish observed between POF-1 and HAC-13; salvage completed on August 15-16, 2017

9-Sep-17 Fish observed near POF-1; salvage completed on Sept 10, 2017 10-Sep-17

15-Oct-17 No fish observed

16-Oct-17 11-Nov-17 No fish observed; channel approx 60% covered in ice

19-Dec-17 Channel approx. 95% covered in ice; no inspection completed


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7.6 Hydrology

In 2017, hydrological monitoring in Hazeltine Creek was completed at sites H1 (Upper Hazeltine Creek), H2 (Lower Hazeltine Creek) and H4 (Polley Lake outlet), as required by Section 3.4 of EMA Permit 11678 and Section 5.3.2 of the CEMP (Appendix A). Manual flow measurements were taken from January through November when flow rates were sufficient. Due to the remediation efforts around the upper Hazeltine Creek area between June and September 2017, flow was controlled by the Polley Lake weir and not indicative of the natural flow regime. The flow regime was also impacted by the discharge from the WTP, with incremental flow contributions not exceeding 0.3 m3/s.

Tables and figures presenting the 2017 hydrology results at all sites, including hydrographs, stage discharge rating curves, pressure-stage relations, goodness of fit statistics and photographs are presented in Appendix K.

7.6.1 Site H1 - Upper Hazeltine Creek

Seven (7) staff gauge readings and five (5) manual flow measurements were taken between April 22 and October 29, 2017. The highest manually measured discharge rate was 0.41 m3/s on July 9, 2017.

Pressure transducer data from a PT2x were recorded from April 14 to October 10, 2017. Gaps in the data from May 8 to May 27, 2017 can be attributed to water in the connector cap. The pressure transducer was replaced on May 27, 2017. Data gaps from May 27 to July 5, 2017 incurred from an equipment malfunction; the equipment has since been updated. The PT2x was removed in mid-October due to freezing temperatures. A benchmark survey conducted on August 29 by WaterSmith indicated the stilling well and staff gauge had been stable, and the water level data did not require adjustment.

A stage-discharge rating curve was developed to relate the staff gauge readings and the manual discharge measurements made in 2017, and a stage-pressure relation was developed between the manual staff gauge readings and the automated pressure data to allow application of the rating curve to the automated pressure data. An assessment of the goodness of fit of the manual readings to the stage-discharge rating curve yielded a mean difference of 7.2% and a standard error of 9.1%. The stage-discharge rating curve is provided in Appendix K.

Continuous records of stage and discharge values for the monitoring season were generated from PT2x data. Discharge fluctuated during April and May due to the freshet and flow control by the weir. Flow peaked in May and steadily declined in July. Sporadic heavy precipitation events contributed to the increases seen in late September and early October. Note that the large variation in flow at times was generated by opening and closing the weir gate at Polley Lake. The gate adjustments were made to facilitate the remediation work in Hazeltine Creek. The highest calculated discharge rate was 0.48 m3/s on May 5, 2017.


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7.6.2 Site H2 - Lower Hazeltine Creek

Ten (10) staff gauge readings and eight (8) manual flow measurements were taken between April 22 and November 12, 2017. The highest manually measured discharge rate was 0.52 m3/s on May 23, 2017. The stage-discharge rating curve based on 2017 data is included on the graph in Appendix K.

Pressure transducer data from a PT2x were recorded from April 15 to October 10, 2017. The PT2x was removed in mid-October due to freezing temperatures. A benchmark survey conducted on August 29 by WaterSmith indicated the stilling well and staff gauge had been stable and the water level data did not require adjustment. The goodness of fit assessment yielded a mean difference of 16.1% and a standard error of 14.6%.

Continuous records of stage and discharge for the monitoring season were generated from the pressure transducer data. Discharge was punctuated with elevated peaks during freshet in April and May. Flow decreased at the end of July, staying consistently low during the rest of the record. Note that the large range of flow at times was consistent with the opening and closing of the weir gate at Polley Lake. This was to facilitate the remediation activities in Hazeltine Creek. The highest calculated discharge rate was 2.44 m3/s on April 18, 2017.

7.6.3 Site H4 - Polley Lake Weir

Installation of a stilling well, staff gauge and weir was completed in October 2016. Twelve (12) staff gauge readings and six (6) manual flow measurements were taken between January 31 and August 29, 2017. The highest measured discharge rate was 0.43 m3/s on May 27, 2017.

Pressure transducer data from a PT2x were recorded from April 25 to November 11, 2017. A benchmark survey conducted on August 29 by WaterSmith indicated the stilling well and staff gauge had been stable and the water level data did not require adjustment. An assessment of the goodness of fit of the manual readings to the stage-discharge rating curve yielded a mean difference of 7.1% and a standard error of 7.1%. The stage-discharge rating curve is provided in Appendix K.

Continuous records of stage and discharge values for the monitoring season were generated from the PT2x data. Peaks occurred in May and June as flow declined to its lowest in early July. Flow peaked again in late July only to decrease again until early November. Heavy precipitation events in November caused flows to peak again. Note that the large variation in flow at times was generated by opening and closing the weir gate at Polley Lake. The gate adjustments were made to facilitate the remediation activities in Hazeltine Creek in 2017. The highest calculated discharge rate was 0.7 m3/s on November 14, 2017.


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8 Aquatic Receiving Environment

8.1 Surface Water Quality

Surface water monitoring and analysis was conducted as outlined in the CEMP (Appendix A). Refer to Section 4.3 for a discussion of field sampling equipment and methodology. Sampling stations and frequency are summarized in Table 8.1 and locations are shown in Appendix B.

Table 8.1 Sampling events in 2017 at surface water quality sites


Frequency

Permit Requirement Actual Total

W1 E225084 Monthly 12 12

W4a E298551 Monthly 12

19 Weekly (a) 7

W5 E208039 Monthly 11

18(d) Weekly (a) 7

W8 E216743 Quarterly 5

13 Weekly (a) 8

W8z E223292 Quarterly 3 3 (e)

W10 E291209 Monthly 12

17 Weekly (b) 5

EDC-01 E303014 Monthly 11(c)

16 Weekly (b) 5

W12 E216744 Quarterly 4 4 W20 E297070 Quarterly 2 (f) 2

(a) Weekly TSS and turbidity sampling for five (5) weeks during spring freshet and autumn low flows (b) Weekly at W10 and EDC-01 was only taken during freshet. (c) Sample missed in August (d) Dry on July 4, 2017. (e) Dry on August 1, 2017. (f) Frozen, not enough water to sample on February 16, 2017; Dry on August 7, 2017.

Samples were submitted to ALS for analysis of:

• Physical parameters (pH, turbidity, TSS, total dissolved solids, and hardness); • Anions and nutrients (alkalinity, chloride, fluoride, sulphate, total nitrogen, nitrate, nitrite, ammonia,

phosphorus total and dissolved, and ortho-phosphorus); • Organics (dissolved organic carbon); and • Total and dissolved metals (metals suite as listed in CEMP Appendix A).

Water chemistry results from the surface sites were compared with the BCWQG for aquatic life for both


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short-term (maximum or acute) and long-term (chronic) exposures. In 2017, there were twenty-four (24) exceedances of the acute BCWQG for aquatic life at the permitted surface water monitoring sites (Table 8.2). Note that the list of analytes with concentrations greater than BCWQG is similar to baseline. Exceedances for the chronic BCWQG for dissolved aluminum, total copper, total chromium and total selenium occurred at various sites, however, since only monthly or quarterly sampling is conducted at these sites, the required five samples taken in thirty days to calculate the average was not met (with the exception of W10 and EDC-01). Therefore, these comparisons are for screening purposes only (Meays 2012) and are not listed in Table 8.2; they are described in the individual site sections below.

Prior to the TSF embankment breach elevated concentrations of selenium were observed in the mine’s receiving environment (Minnow 2011, 2013a, b), and following the breach there were elevated selenium levels in impacted areas. MPMC is working with Minnow to monitor the selenium in the receiving environment to document special and temporal differences in concentrations and relationships among media. A summary report of data collected between 2009 and 2017 is provided in Appendix J.

At sites W4a, W5, and W8 weekly intensive sampling of TSS and turbidity occurred during spring (freshet) and fall (low flow period); and a 30-day average could be calculated; these were therefore appropriately compared to chronic TSS and turbidity BCWQG as summarized in Table 8.3. Intensive sampling also occurred at W10 and EDC-01 in spring and chronic BCWQG are applicable and are listed in Table 8.3. Additional details for each site are provided in the following sections and Appendix E. Appendix E includes tables of results for the past five years and graphs of select parameters. Note that only parameters with trends and/or exceedances are discussed the sections below. It was noted at time of publishing that the 95th percentile presented on the graphs may be incorrect; MPMC is working with the database provider to rectify this issue. Note that results below method detection limit (MDL) are represented as half (0.5x) the MDL in statistical calculations and graphs.

Table 8.2 Summary of acute BCWQG exceedances for aquatic life at surface water monitoring sites

Site Parameter Results Acute BCWQG (mg/L)

W1 Dissolved aluminum 0.133 mg/L 0.1

Total copper 0.00806 mg/L; 0.00683 mg/L 0.0058-0.0131(a)

W4a Total copper 3 exceedances - see Section 8.1.91 for

details 0.011-0.0227 (a)

Total iron 1.49 mg/L 1.0

W5 Dissolved aluminum 3 exceedances - see Section 8.1.3 for details 0.1

Total copper 0.00921 mg/L; 0.0103 mg/L 0.0044-0.0198 (a) W8 Dissolved aluminum 0.250 mg/L 0.1

W8z Dissolved aluminum 3 exceedances - see Section 8.1.5 for details 0.1

Dissolved iron 0.365 mg/L 0.35 W10 Dissolved aluminum 3 exceedances - see 8.1.6 for details 0.1

EDC-01 Dissolved aluminum 0.117 mg/L; 0.172 mg/L 0.1 W20 Dissolved aluminum 0.152 mg/L 0.1


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Total copper 0.00698 mg/L 0.0076-0.0155(a)

(a) Hardness dependent copper guideline; range given is based on hardness range at each site, when available.

Table 8.3 Summary of chronic BCWQG exceedances for aquatic life at surface water monitoring sites. Note that this only applies to sites where five (5) samples were collected in 30 days.

Site Parameter Results Chronic BCWQG (mg/L)

W4a TSS 6 exceedances - see Section 8.1.92 for

details 5 mg/L change from

background in 30 days

Turbidity 7 exceedances - see Section 8.1.92 for details

2 NTU change from background in 30 days

W5 Turbidity 4 exceedances - see Section 8.1.3 for details 2 NTU change from background in 30 days

W8

TSS 4 exceedances - see Section 8.1.4 for details 5 mg/L change from background in 30 days

Turbidity 5 exceedances - see Section 8.1.4 for details 2 NTU change from background in 30 days

W10

Dissolved aluminum 7 exceedances - see Section 8.1.6 for details 0.05 mg/L Total copper 2 exceedances - see Section 8.1.6 for details 0.0018-0.0078 mg/L(a)

Total chromium 3 exceedances - see Section 8.1.6 for details 0.001 mg/L (b)



EDC-01

Dissolved aluminum 6 exceedances - see Section 8.1.7 for details 0.05 mg/L Total copper 3 exceedances - see Section 8.1.7 for details 0.0019-0.0079 mg/L(a)

Total chromium 3 exceedances - see Section 8.1.7 for details 0.001 mg/L (b) Total selenium 1 exceedance - see Section 8.1.7 for details 0.002 mg/L



(a) Hardness dependent copper guideline; range given is based on hardness range at each site, when available.

(b) Based on the BC working water quality guidelines (BCWWQG) for Chromium (Cr(VI))

8.1.1 Site W1 – Morehead Creek (E225084)

This site was sampled twelve (12) times in 2017. Graphs for a subset of parameters are provided in Appendix E. There were three (3) acute BCWQG exceedances at this location in 2017. A decrease in acute BCWQG exceedances was observed compared to 2016; therefore monitoring will continue as outlined. Notable observations in the results were:

Hardness: An increase in hardness was first observed in 2015 and hardness remained elevated in 2017 in


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fall and early winter, but was lower than or similar to previous years. In 2017, the maximum was 119 mg/L compared 163 mg/L in 2016, and the 2017 annual mean was 72 mg/L compared to 61 mg/L in 2016.

Sulphate: A general increase in sulphate levels has been recorded at W1 since 2005. In 2017 levels increased starting in October with a maximum of 36.4 mg/L (compared to a maximum of 12.1 mg/L in 2016) and an annual mean of 11.0 mg/L (7.21 mg/L in 2016). The 2017 levels however, followed the same trend and were comparable to the 2015 results.

Chloride: An increase in chloride has been observed at this site since 2009. The maximum concentration recorded in 2017 was 19.5 mg/L compared to 73.9 mg/L in 2016 (4.78 mg/L in 2015 and 11.4 mg/L in 2014) and the mean was 4.14mg/L compared to 8.11 mg/L in 2016 (2.22 mg/L in 2015 and 4.71 mg/L in 2014).

TSS: A general decrease in TSS was observed in 2017 compared to 2016. The maximum concentration observed in 2017 was 5.7 mg/L in June, which is above chronic BCWQG (see description in Section 8.1). The annual mean was 2.79 mg/L.

Dissolved Aluminum: There was one (1) acute exceedance for dissolved aluminum in 2017. The maximum concentration recorded above the BCWQG in 2017 was 0.133 mg/L in April. The annual mean was 0.034 mg/L. There were two (2) chronic exceedances (see description in Section 8.1).

Total Copper: There were two (2) acute guideline exceedances in the results for total copper in 2017; 0.00806 mg/L and 0.00683 mg/L were recorded in April and May respectively. The maximum concentration recorded above the BCWQG in 2017 was in April; an elevated result also occurred at the same period in 2016. The annual mean was 0.0048 mg/L. There were ten (10) chronic exceedances (see description in Section 8.1).

8.1.2 Site W4a – North Dump Creek below Wight Pit Road (E298551)

This site replaced site W4 on July 7, 2014. W4a was sampled twelve (12) times in 2017 for full metals suites and seven (7) times for turbidity and TSS only. Graphs are provided in Appendix E. There were four (4) acute BCWQG exceedance at this location in 2017. An increase in acute exceedances was observed compared to 2016; however, two of the exceedances occurred due to road runoff during an unexpected melting event and the other two occurred during freshet, therefore monitoring will continue as outlined. Additional metals sampling may be undertaken during the TSS and turbidity programs to understand the scope of the chronic BCWQGs. Notable observations in the results were:

Dissolved Aluminum: There were no acute or chronic exceedances for dissolved aluminum in 2017. The annual mean was 0.009 mg/L and the maximum concentration at this location was 0.040 mg/L in May 2017.

TSS: A maximum value of 138 mg/L was observed in October. This elevated result was due to a heavy rainfall


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event as the weekly results before and after are both below detection limit. The manual rain gauge had collected 8.2 mL in the two (2) days prior and 16.8 mL in the three (3) days after. The annual mean at this site was 22.87 mg/L. There were eight (8) chronic exceedances: two (2) from monthly samples in February and March (see description in Section 8.1), four (4) ranged from April 5 to May 4, 2017 during the weekly intensive spring sampling and two (2) ranged from September 5 to October 10, 2017 during the weekly fall intensive sampling. Chronic exceedances were comparable with W8 during the spring (freshet) sampling events.

Turbidity: A maximum value of 145 NTU was observed in October. This elevated result was due to a heavy rainfall event as the weekly results before and after are both below detection limit. The manual rain gauge had collected 8.2 mL in the two (2) days prior and 16.8 mL in the three (3) days after. The annual mean at this site was 11.3 NTU. There were nine (9) chronic exceedances: two (2) from monthly samples in February and March (see description in Section 8.1), five (5) ranged from April 5 to May 4, 2017 during the weekly intensive spring sampling and two (2) ranged from September 5 to October 10, 2017 during the weekly fall intensive sampling. Chronic exceedances were comparable with W8 during the spring (freshet) sampling events.

Total Copper: There were three (3) acute exceedance for total copper in 2017. The maximum value was observed at 0.0724 mg/L in February; this result appears to be an outlier as there may have been road runoff influence as the field notes express that the water was cloudy at the time of sampling. Other results that were above acute BCWQG occurred in April and May with concentrations of 0.0155 mg/L and 0.0121 mg/L respectively. The annual mean was 0.0128 mg/L. There were five (5) chronic exceedances from February to June (see description in Section 8.1).

Total Iron: There was one (1) acute exceedance for total iron in 2017. The maximum value was observed at 1.49 mg/L in February. This exceedance may have had road runoff influence as the field notes express that the water was cloudy at the time of sampling. The annual mean was 0.314 mg/L.

Total Selenium: A maximum of 0.0021 mg/L was observed in April and May, which is slightly above the BCWQG (see description in Section 8.1). The annual mean was 0.0014 mg/L.

8.1.3 Site W5 – Bootjack Creek (E208039)

This site was sampled twelve (12) times for full metals suite and seven (7) times for TSS and turbidity only. Graphs are included in Appendix E. There were five (5) acute BCWQG exceedances at this location. A decrease in acute exceedances was observed compared to 2016; therefore monitoring will continue as outlined. Additional metals sampling may be undertaken during the TSS and turbidity programs to understand the potential for exceedance of chronic BCWQGs. Notable observations in the results were:

Hardness: A maximum hardness of 189 mg/L was observed in November; elevated levels above 100 mg/L


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were also observed from August to November. The annual mean is 95.9 mg/L.

Sulphate: A maximum concentration of sulphate was observed at 39.1 mg/L in November. All other results were below 17.5 mg/L (except in December when the concentration was 32 mg/L) and the annual mean was 12.6 mg/L.

Dissolved Aluminum: There were three (3) acute BCWQG exceedances at this location in 2017. The maximum value above the acute BCWQG was 0.172 mg/L in May. Two (2) more exceedances occurred in April and December. The annual mean was 0.055 mg/L. There were three (3) chronic exceedances in April, May and November (see description in Section 8.1).

Total Copper: There were two (2) acute exceedances at this location in 2017. The maximum value above the BCWQG was 0.0103 mg/L in April. Another exceedance occurred in May with a result of 0.00921 mg/L. The annual mean was 0.007 mg/L. There were nine (9) chronic BCWQG exceedances from January to August and November to December (see description in Section 8.1).

TSS: The maximum concentration observed in 2017 was 10 mg/L in November. Two (2) results exceeded the chronic BCWQG from samples collected in August and November (see description in Section 8.1) but were not part of the five weekly sampling events from April 5 to May 4, 2017 and September 4 to October 10, 2017. The annual mean was 3.51 mg/L.

Turbidity: A maximum value of 6.95 NTU was observed in November. The elevated result was due to chopping through the ice to obtain a sample and in the process, disturbing the water. The TSS result was also elevated during the same sampling event. The annual mean at this site was 1.69 NTU. There were six (6) chronic exceedances: two (2) from monthly samples in February and November (see description in Section 8.1), and four (4) ranged from April 5 to May 4, 2017 during the weekly intensive spring sampling. Chronic exceedances were comparable with W8 during the spring (freshet) sampling events.

8.1.4 Site W8 – Northeast Edney Creek Tributary (E216743)

This site was sampled five (5) times in 2017 for full metals suite and eight (8) times for turbidity and TSS only. Graphs are provided in Appendix E. There was one (1) acute BCWQG exceedance at this location in 2017. A decrease in acute exceedances was observed compared to 2016; therefore monitoring will continue as outlined. Additional metals sampling may be undertaken during the TSS and turbidity programs to understand the scope of the chronic BCWQGs. Notable observations in the results were:

Dissolved Aluminum: There was one (1) acute exceedance at this location in 2017. The maximum value was 0.250 mg/L in May. The annual mean was 0.035 mg/L. There was one (1) BCWQG chronic exceedance in May (see description in Section 8.1).


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Total Copper: There were no acute BCWQG exceedances at this location in 2017. A maximum of 0.0038 mg/L was observed in May, which is above the chronic BCWQG (see description in Section 8.1). The annual mean was 0.0016 mg/L.

Total Chromium: A maximum of 0.0015 mg/L was observed in August, which is above the chronic BCWWQG (see description in Section 8.1). The annual mean was 0.0009 mg/L.

TSS: The maximum concentration observed in 2017 was 26.5 mg/L in May. The annual mean was 5.81 mg/L. There were four (4) chronic BCWQG exceedances that spanned the five samples collected weekly from April 5 to May 4, 2017. Five samples collected weekly from September 18 to October 19, 2017 did not result in any chronic exceedances.

Turbidity: A maximum value of 3.04 NTU was observed in April. The annual mean was 1.34 NTU. There were four (4) chronic BCWQG exceedances that spanned the five samples collected weekly from April 5 to May 4, 2017. Five samples collected weekly from September 18 to October 19, 2017 did not result in any chronic exceedances.

8.1.5 Site W8z – Southwest Edney Creek Tributary (E223292)

This site was sampled three (3) times in 2017 (see Table 8.1). It should be noted that this is a control site, as it is not downstream of any Mount Polley Mine components. Graphs are provided in Appendix E. There were four (4) acute BCWQG exceedances at this location in 2017. A decrease in acute exceedances was observed compared to 2016; therefore monitoring will continue as outlined. Notable observations in the results were:

Dissolved Aluminum: There were three (3) acute BCWQG exceedances at this location. The maximum value was 0.280 mg/L in February, which is the range of historical levels. The two other exceedances were 0.187 mg/L and 0.227 mg/L in May and November 2017 respectively. The annual mean was 0.23 mg/L. There were three (3) chronic BCWQG exceedances in 2017 (see description in Section 8.1).

Total Copper: There were no acute BCWQG exceedances at this location. The maximum value above the BCWQG was 0.00508 mg/L in November, which is within the range of historical levels. The annual mean was 0.0043 mg/L. There were three (3) chronic BCWQG exceedances in 2017 (see description in Section 8.1).

Dissolved Iron: There was one (1) acute exceedance at this location. The maximum value was 0.365 mg/L in February. The annual mean was 0.279 mg/L.

Total Chromium: A maximum of 0.0018 mg/L was observed in November, which is above the chronic BCWWQG (see description in Section 8.1). Another chronic exceedance occurred in February. The annual mean was 0.0014 mg/L.


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TSS: TSS remained below detection limit at this site in 2017.

Turbidity: A maximum value of 2.13 NTU was observed in November. The annual mean was 1.80 NTU. Chronic BCWQG do not apply as there samples were taken quarterly at this site (see description in Section 8.1).

8.1.6 Site W10 – Edney Creek (E291209)

Prior to this becoming a permitted site there were only a few samples collected here since 1995. This site was sampled for full metals monthly with a five (5) weekly intensive sampling program during freshet in 2017. This site is a reference site and not impacted by mining activities. This site is selected for comparisons to the sites downstream from the mine disturbance, including a site in the re-engineered channel of Edney Creek. Graphs are provided in Appendix E. There were three (3) acute BCWQG exceedances at this location in 2017. A decrease in acute exceedances was observed compared to 2016; therefore monitoring will continue as outlined. Notable observations in the results were:

Dissolved Aluminum: There were three (3) acute BCWQG exceedances at this site. Two occurred in April with values of 0.196 mg/L and 0.117 mg/L and the other occurred in May with a value of 0.101 mg/L. Elevated values are comparable during the freshet period in 2015 and 2016. The annual mean was 0.058 mg/L. There were eight (8) chronic BCWQG exceedances: one (1) in January (see description in Section 8.1) and seven (7) spanning from April 3 to May 23, 2017 during the intensive sampling.

Total Copper: There were no acute BCWQG exceedances at this site in 2017. The maximum value recorded was 0.0038 mg/L in April. The annual mean was 0.0024 mg/L with a maximum of 0.0038 mg/L recorded in April. There were two (2) chronic BCWQG exceedances in April and May 2017 during the intensive weekly sampling.

Total Chromium: Chronic BCWWQG exceedances occurred three (3) times in April with a maximum concentration of 0.0014 mg/L during the intensive spring sampling program. The annual mean was 0.0009 mg/L.

TSS: Chronic BCWQG exceedances occurred three (3) times in April and once in May during the intensive sampling program. A maximum of 11.8 mg/L was observed in April and the annual mean was 6.1 mg/L.

Turbidity: Chronic BCWQG exceedances occurred seven (7) times during the intensive spring sampling program. A maximum of 6.36 NTU was observed in April and the annual mean was 2.04 NTU.


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8.1.7 Site EDC-01 – Edney Creek below constructed channel (E303014)

Located just upstream of the mouth of the creek near Quesnel Lake, this site was established in February 2015 after the newly constructed Edney Channel was completed and opened to fish passage. This site is used to monitor any potential impacts on Edney Creek following the TSF embankment breach and associated remediation works. This site was sampled monthly (except August 2017, see Table 8.1) with a five (5) weekly intensive sampling program during freshet in 2017. There were two (2) acute exceedances at this site. A decrease in acute exceedances was observed compared to 2016; therefore monitoring will continue as outlined. Considering W10 as the background site for Edney Creek, the following observations are noted:

Dissolved Aluminum: There were two (2) acute BCWQG exceedances at this site. The maximum value was 0.172 mg/L in April. The other BCWQG exceedance also occurred in April with a concentration of 0.117 mg/L. Chronic BCWQG exceedances occurred once in January and April (see description in Section 8.1). There were six (6) chronic BCWQG exceedances spanning from April 18 to May 23, 2017 during the intensive weekly samples. Comparing these results to W10, the levels at EDC-01 were similar.

Total Copper: There were no acute BCWQG exceedances at this site. The maximum value recorded was 0.0071 mg/L in February. The annual mean was 0.0036 mg/L at EDC-01 compared to the mean of 0.0024 mg/L at W10. Chronic BCWQG for total copper was exceeded once in February (see description in Section 8.1). There were three (3) chronic BCWQG exceedances spanning from April to June 2017 during the intensive weekly samples similar to W10.

Total Iron: There were no acute BCWQG exceedances at this site. The maximum value recorded at this site was 0.74 mg/L in April. The annual mean was 0.30 mg/L at EDC-01 compared to the mean of 0.27 mg/L at W10.

Dissolved Iron: There were no acute BCWQG exceedances at this site. The maximum value recorded at this site was 0.25 mg/L in March. The annual mean was 0.16 mg/L at EDC-01 and W10.

Total Chromium: Chronic BCWWQG guidelines were exceeded three (3) times in April with a maximum result of 0.0015 mg/L. Another exceedance occurred in December with a result of 0.0014 mg/L (see description in Section 8.1). The annual mean was 0.00095 compared to 0.0009 mg/L at W10.

Ammonia: There were no chronic BCWQG exceedances at this site in 2017. A maximum of 0.0123 mg/L was recorded in January at EDC-01 compared to a maximum concentration of 0.013 mg/L in January at W10. The annual mean at both locations was 0.008 mg/L.

Nitrate: Nitrate was slightly higher than the background site but well below the maximum BCWQG at a


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mean of 0.138 mg/L compared to a mean of 0.0655 mg/L at W10.

Sulphate: Results were above sulphate levels at W10 for much of the year, but remained below the BCWQG. The maximum observed was 65.4 mg/L in February and the mean annual value was 12.1 mg/L compared to a maximum of 14.7 mg/L in October and a mean of 5.66 mg/L at W10.

TSS: Chronic BCWQG exceedances occurred once in January (see description in Section 8.1) and three (3) times in April during the intensive sampling program. Results were similar throughout the year with a maximum of 13.0 mg/L was observed in April and the annual mean was 6.38 mg/L at EDC-01 compared to a maximum of 11.8 mg/L in April and an annual mean of 6.1 mg/L at W10.

Turbidity: Chronic BCWQG exceedances occurred once in February (see description in Section 8.1) and six (6) times during the intensive spring sampling program. A maximum of 7 NTU was observed in April and the annual mean was 2.17 NTU at EDC-01 compared to a maximum of 6.36 NTU was observed in April and the annual mean was 2.04 NTU at W10.

Total Molybdenum: Results were somewhat elevated compared to background, but remained below the BCWQG. The maximum for 2017 at EDC-01 was 0.0141 mg/L in February and the annual mean was 0.002 mg/L, compared to a maximum of 0 .0024 mg/L and a mean of 0.0009 mg/L at W10.

Total Selenium: The maximum at EDC-01 was 0.0030 mg/L in February, which is above the chronic BCWQG (see description in Section 8.1); this appears to be an outlier considering that the annual mean was 0.0004 mg/L. The maximum selenium concentration at W10 was 0.0002 mg/L and the mean was 0.0001 mg/L.

Total arsenic, cadmium, and zinc were all similar to the upstream station of W10.

8.1.8 Site W12 – 6K Creek at Road (E216744)

This site was sampled four (4) times in 2017. Graphs are provided in Appendix E. No acute BCWQG exceedances were found in 2017; therefore, monitoring will continue as outlined. Notable observations in parameters results were:

Total Copper: There were no acute BCWQG exceedances at this site in 2017. The annual mean was 0.0042 mg/L with a maximum of 0.0062 mg/L recorded in May. There were two (2) chronic BCWQG exceedances in February and May (see description in Section 8.1).

TSS: The maximum concentration observed in 2017 was 10 mg/L in May. The annual mean was 5 mg/L. There was one chronic BCWQG exceedance in May (see description in Section 8.1).

There were no other changes in parameters observed at this location in 2017 compared to past years.


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8.1.9 Site W20 – W20 Creek (E297070)

This site was sampled two (2) times in 2017 (see Table 8.1). Graphs are provided in Appendix E. There were no notable changes in parameters observed at this location in 2017 compared to past years. There were two (2) acute BCWQG exceedances at this location in 2017. A decrease in acute exceedances was observed compared to 2016; therefore monitoring will continue as outlined. Notable observations in parameters results were:

Dissolved Aluminum: There was one (1) BCWQG acute exceedance at this site. The maximum value above the acute BCWQG was 0.156 mg/L in May, which falls within the historical range. The annual mean was 0.108 mg/L. There were two (2) chronic BCWQG exceedances (see description in Section 8.1).

Total Copper: There was one (1) BCWQG acute exceedance at this site. The maximum value above the acute BCWQG was 0.0069 mg/L in May, which falls within the historical range. The annual mean was 0.0054 mg/L. There was one (1) chronic BCWQG exceedances (see description in Section 8.1).

Total Selenium: The maximum at W20 was 0.0005 mg/L in November, which is below the chronic BCWQG (see description in Section 8.1). After 2014, selenium has been decreasing and the trend continued in 2017 with a mean of 0.0004 mg/L.

8.2 Lake Sampling

In 2017, lake sampling (see Table 8.4) was completed as outlined in the CEMP in Appendix A. Refer to Section 4 for a discussion of field sampling equipment and methodology and Appendix B for site map.

Appendix L includes tables of all results for the past five years and graphs of the parameters measured.

Table 8.4 Lake water quality sampling locations in 2017


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Site Site

Identifier (EMS No.)

Profile Frequency Sample Frequency

Permit Requirement Actual Permit Requirement Actual

P1 E207974 Bi-monthly 9

Monthly 6 P2 E207975 Bi-monthly 10

Monthly 7

B1 E207972 Bi-monthly 8

Bi-annually 4 B2 E215897 Bi-monthly 8

Bi-annually 4

B4 Bi-monthly 7 - - QUL-ZOO-1 E306455 Bi-annually 1

Bi-annually 2 QUL-ZOO-7 E306456

Bi-annually 2

Bi-annually 2

QUL-ZOO-8 E306457 Bi-annually 0

Bi-annually 0 QUL-55 E303017 Supplemental 11 Supplemental 8 QUL-66a E303024 Supplemental 5 Supplemental 2 QUL-2a E303020 Monthly (a) 7 Monthly (a) 7 QUL-18 E303019 Monthly (a) 8 Monthly (a) 8

QUL-120a E303022 Seasonally/Bi-annually

3 Seasonally/Bi-annually 3 HOR-2 Supplemental - Supplement 6

(a) Monitoring is only conducted twice during winter at these sites

8.2.1 Bootjack Lake

In Bootjack Lake, station B1 is located at the northwest end of the lake and station B2 is located at the southeast end. It was discovered that in late 2016, the previous stations were not at the deepest locations for the 2016 monitoring season and these sites were relocated to the deepest areas for monitoring in 2017. Sampling occurred during spring turnover in May and in late summer in September and in fall in October. Limnological profiles were taken bi-monthly (with the exception of May, June and July when only one profile was collected) at stations B1 and B2 as per Section 8.1.2.2 in CEMP (Appendix A). Profile and chemistry data are presented in Appendix L.

In 2016, four (4) locations (B3, B4, B5, and B6) were created near areas of potential exfiltration from the Springer Pit supernatant. Based on the 2016 results it was determined in 2017 that one location, B4, would be profiled bi-monthly. As the Springer Pit supernatant elevation is well below the recommended 1030 masl (Golder 2016b). Profiles were only conducted once a month except for in September when two profiles were collected. Only one profile was taken in May due to late ice coverage; wildfires in the area caused a site wide evacuation in July; and air quality was unsafe in August.

8.2.1.1 In Situ Data

In 2017, MPMC recorded profile data at B1 and B2 eight (8) times. Profiles of pH, conductivity, dissolved oxygen, turbidity, and temperature as well as secchi depth were measured at B1 and B2 on Bootjack Lake twice per month from May to October 2017. During the lake turnover event in spring 2017 as well as


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throughout the year, field parameters were consistent with previous years.

Profiles were taken at B4 intermittently between May and October. No noticeable increases of any parameter were identified at this additional site. Investigations were conducted using specific conductivity to locate areas of possible exfiltration from the Springer Pit supernatant at various depths. According to Golder, (2017), as the Springer Pit level has drastically decreased since June 2016 it has become a groundwater sink in both upgradient and downgradient groundwater and therefore the results of no exfiltration detected in Bootjack Lake are expected.

8.2.1.2 Lake Water Chemistry

Water samples for analytical chemistry were collected at surface, bottom, and every 10 m when the lake is isothermal and at surface, bottom, and every 5 m when the lake is not isothermal at sites B1 and B2. Appendix L contains water chemistry data tables with results from the last five years. Total iron, total manganese and total phosphorus levels exceeded aquatic BCWQGs for samples collected near the bottom of B1 and B2 during sampling events in September, due to conditions at the bottom becoming anoxic with the fall turnover. Historically, MPMC has not sampled during fall turnover on Bootjack Lake and therefore did not have baseline data for comparison. There have been no other significant changes in water chemistry in Bootjack Lake.

Further information on Bootjack Lake water quality is included in Appendix J with details on the results of Diffusive Gradient in Thin Films Device (DGT) sampling completed by Minnow.

8.2.2 Polley Lake

In Polley Lake, station P1 is located at the deepest point at the north end of Polley Lake and station P2 is located at the deepest point at the south end of Polley Lake and are shown in Appendix A. Sampling occurred monthly between spring and fall overturn; limnological profiles were conducted bi-monthly along with the secchi depth during the same period as per Section 8.1.2.3 in the CEMP (Appendix A). Due to evacuation from wildfires in the area, no sampling and only one profile occurred in the month of July. Only one sampling event occurred in winter 2017 at P2. Profile and chemistry data are presented in Appendix L.

Polley Lake was impacted by the TSF embankment breach that occurred in 2014 (MPMC, 2015a) and sample results for water quality show that some water chemistry results are elevated from historic and baseline levels. All results are included in Appendix L.

8.2.2.1 In Situ Data

In 2017, MPMC recorded profile data at P1 and P2 nine (9) and ten (10) times, respectively. Note that P1 was not accessible during the ice sampling event in 2017; therefore no profile was recorded. Profiles of pH, specific conductivity, dissolved oxygen, turbidity and temperature were measured at P1 and P2 twice a


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month in May, June, and August 2017; as mentioned above, July only had one profile complete. During the lake turnover event in spring 2017 as well as throughout the year, field parameters were consistent with previous years.

In Polley Lake, conductivity historically ranged from 192 to 215 µS/cm. Following the breach, the conductivity increased to a maximum of 342 µS/cm at P1 and 338 µS/cm at P2. Conductivity throughout Polley Lake appears to be decreasing slightly since the breach; however, it remains elevated above historic levels. In 2017, the average conductivity recorded at P1 was 273 µS/cm and at P2 was 277 µS/cm.

In Polley Lake, pH historically ranged between 7.58 and 9.18 at P1 and from 7.6 and 9.09 at P2. Following the breach, pH remains similar with a range of 7.58 to 8.81 at P1 and from 7.57 to 8.76 at P2.

Further information on Polley Lake water quality is included in Appendix J with details on the results of DGT sampling completed by Minnow.

8.2.2.2 Water Chemistry

In 2017, water samples for analytical chemistry were collected at surface, bottom, and every 5 m when conditions were not isothermal and every 10 m when isothermal at sites P1 and P2. These data are presented in Appendix L.

Water quality monitoring completed by MPMC includes total and dissolved metals. According to Minnow, total and dissolved metals over-represent the metal fraction that is potentially available for uptake by aquatic organisms in natural surface waters. Minnow’s technical memo “Results of Diffusive Gradients in Thin Films Device Deployment” (Appendix J), describes the methods and results for the DGT deployments for 2017. Key findings for Polley lake include that mean DGT-labile copper concentrations are very low (0.00052 mg/L) however they are higher than in Bootjack Lake (the reference), and DGT labile concentrations in Polley Lake of arsenic, molybdenum, selenium and vanadium were enriched compared to Bootjack Lake. However, total concentrations of these metals were below the BCWQG.

8.2.3 Quesnel Lake

8.2.3.1 Quesnel Lake Zooplankton Sites

In Quesnel Lake, site QUL-ZOO-1 is located in the centre of the West Basin, QUL-ZOO-7 is located in front of Horsefly Bay, and QUL-ZOO-8 is located at the junction of the North, East and West Arms (Appendix B). Sampling and limnological profiles occurred bi-annually as per Section 8.5.2 in the CEMP (Appendix A). Note that QUL-ZOO-8 was not sampled in 2017 due to unsafe conditions caused by unfavourable weather and forest fires in the area, and one profile for QUL-ZOO-1 was not recorded due to equipment malfunction. MPMC continues to collect profile and surface water quality data from these sites to be used in the analysis of plankton results (see Section 8.6).


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8.2.3.2 Quesnel Lake Receiving Environment Sites

The far-field receiving environment in Quesnel Lake is monitored at QUL-18 (the deepest area of the West Basin, downstream far-field exposure station) and QUL-2a (West Basin upstream of the mouth of Hazeltine Creek; to monitor for potential eastward flow of effluent due to seiche events). Sampling and limnological profiles at depths as outlined in the 2016 CEMP (Appendix A), occurred monthly between April and November with the exception of July due to site wide mandatory evacuation because of active forest fires in the area. Supplement sites were monitored in 2017: QUL-55 (approximately 200 m upstream of Hazeltine Creek near the outlet of Edney Creek) and QUL-66a (deep site beyond the mouth of Hazeltine Creek), HOR-2 (Horsefly River approximately 2.6 km upstream of Quesnel Lake). These sites are not required sites in the 2016 CEMP; however MPMC collected data at these sites, as well as from Edney Creek, to compare results with those of permitted sites, to determine how other water sources influence water quality in Quesnel Lake. QUL-55 was sampled eight (8) times and limnological profiles taken eleven (11) times in 2017 (Table 8.4). QUL-66a was sampled two (2) times and limnological profiles taken five (5) times in 2017 (Table 8.4). HOR-2 was sampled six (6) times. The Horsefly River is also part of the Provincial and Federal monitoring program and water quality results and flow data can be found on various government websites.

8.2.3.2.1 Lake Water Chemistry

Quesnel Lake is an oligotrophic lake, therefore, it is common to see total phosphorus concentrations lower than the BCWQG, as was observed at all sites in Quesnel Lake (Appendix L). No acute BCWQG exceedances were found in any of the receiving environment sites for 2017. Additional information related to the discharge water quality are in Section 6.2 and discharge plume modeling in Quesnel Lake are in Appendix I.

QUL-18, considered a receiving environment sample site, was also impacted by the TSF embankment breach. QUL-18 was sampled eight times in 2017. There were no observed changes or trends in the water quality at this site. There were two exceedances of the calculated chronic water quality guideline for copper at this location in 2017, one at a depth of approximately 100 m in April (0.00297 mg/L) and another at the same depth in October (0.00455 mg/L) (see Figure 8.1). This October result appears to be associated with elevated TSS likely a result of hitting the bottom of the lake with the Kemmerer sampler or the profiling equipment. It is important to consider that there are many sources of water contributing to the water quality of Quesnel Lake and many of these sources travel through mineral rich areas. On April 25, 2017 the Horsefly river was flowing at a rate of approximately 53 m3/s and the total copper was reported as 0.00298 mg/L (note MPMC has a permit limit of 0.0022 mg/L which is below this value for the IDZ, see Section 6.2) . On the same date Edney Creek, upstream of the ditch road bridge had a total copper value of 0.00327 mg/L.

At QUL-18, the chronic BCWQG for total chromium was exceeded at a depth of 20 m in November. This sample result appears to be an outlier, potentially from a contaminated sample vessel or sampling error as all other sample results for this site are below the detection limit of 0.0005 mg/L .


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Figure 8.1 Total copper results at QUL-18

At QUL-2a, there were no trends observed and no acute or chronic exceedances were found in the 2017 sampling events.

8.2.3.2.2 Quesnel Lake Reference Sites

An upstream reference station, QUL-120a, is located east of Cariboo Island. Sampling and limnological profiles at depths outlined in the 2016 CEMP (Appendix A), occurred between June and August 2017, with the exception of July due to a site wide evacuation caused by active wildfires in the area. Monitoring at this reference site is planned for once per season; however, due to unfavourable weather conditions in the fall and winter it was unsafe to access this location. Sampling and limnological profiles occurred one (1) time in the spring (April 2017) and two (2) times in the summer (June and August 2017) to coincide with zooplankton sampling events. There were no trends observed and no acute or chronic exceedances were found at QUL-120a in the 2017 sampling events. Figure 8.2 presents the copper monitoring results for QUL-120 at varying depths since 2014.


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Figure 8.2 Total copper results at QUL-120a

8.3 Hydrology

In 2017, hydrological monitoring was completed at sites W1b (Morehead Creek), W4a (North Dump Creek), W5 (Bootjack Creek), W12 (6km Creek), and H3 (Edney Creek) as required by Section 3.4 of the EMA Permit 11678 and Section 6.2 of the CEMP (Appendix A). Supplemental monitoring was carried out at W8 (Northeast Edney Creek Tributary), the Long Ditch, the SERDS, the NW Ditch, Junction Zone Ditch, Joe’s Creek Pipe, the Cut-off Wall Drain, and the Main and South Toe Drains at the TSF. Refer to Appendix B for a map of monitoring locations.

Tables and figures presenting 2017 hydrology results at all sites, including hydrographs, rating curves, pressure transducer figures, and statistical analysis are presented in Appendix K.

8.3.1 Site W1b – Upper Morehead Creek

Three (3) staff gauge readings and two (2) manual flow measurements were taken between April 5 and August 7, 2017. The highest manually measured discharge rate was 0.0561 m3/s on June 21, 2017. The stage-discharge rating curve based on 2016-2017 data is included in Appendix K.


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In 2016, WaterSmith made significant changes to the site including removal of debris and installation of a new stilling well and staff gauge.

No pressure transducer was installed at this site in 2017. A benchmark survey conducted on August 30 by WaterSmith indicated the staff gauge had been stable and the water level data did not require adjustment.

A stage-discharge rating curve was developed using the monitoring results in 2017. An assessment of the goodness of fit of the manual readings to the stage-discharge rating curve yielded a mean difference of 66.1% and a standard error of 69.9%. These error values are inflated by the actual flows being very low, thus, limiting the accuracy of the velocity-based manual flow measurements.

8.3.2 Site W4a – North Dump Creek

At site W4a, ten (10) bucket flow measurements were recorded from a constructed pipe weir between January 5 and December 4, 2017. No staff gauge or pressure transducer was installed at this site in 2017. The highest estimated discharge rate was 0.015 m3/s on April 18, 2017. Flow data is included in Appendix K.

8.3.3 Site W5 – Bootjack Creek above Hazeltine Creek

Four (4) staff gauge readings were taken between April 5 and October 19, 2017. Flow measurements could not collected at this site. Conditions at W5 were difficult in 2017: ice was present at W5 from January to early May and again from November to December; and no flow occurred from July to October. The highest staff gauge reading was 0.238 m on May 4th, 2017. The stage-discharge rating curve based on 2016 data is provided in Appendix K.

A new stilling well and staff gauge were installed on April 13, 2016, approximately ten (10) meters downstream of the previous station.


A stage-discharge rating curve was developed using the monitoring results between April 13 and October 27, 2016. An assessment of the goodness of fit of the manual readings to the stage-discharge rating curve yielded a mean difference of 4.6% and a standard error of 4.2%.

8.3.4 Site W12 – 6 km Creek at Bootjack Road

Five (5) staff gauge readings and two (2) flow measurements were taken between May 4 and September 11, 2017. The highest manually measured discharge rate was 0.057 m3/s on June 10, 2017. The stage-discharge rating curve equation based on 2017 data is included on the graph in Appendix K.


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In 2016, a new stilling well was installed by WaterSmith.


A stage-discharge rating curve were developed using the monitoring results from 2017. An assessment of the goodness of fit of the manual readings could not be determined.

8.3.5 Site H3 – Lower Edney Creek

Nine (9) staff gauge readings and three (3) manual flow measurements were taken between May 4 and August 29, 2017. The highest manually measured discharge rate was 0.0169 m3/s on July 1, 2017. The stage-discharge rating curve based on 2017 data is included in Appendix K.

Pressure transducer data from a PT2x were recorded from April 28 to August 29, 2017. On May 26, 2017, the PT2x was removed from the stilling well as it was noticed that it was not properly seated at the bottom of the well due to an obstruction. The well was adjusted on May 27, 2017 and the PT2x was reinstalled. Data prior to May 27, 2017 have been omitted due to this error. A benchmark survey conducted on August 29 by WaterSmith indicated the stilling well was raised by 0.033m during this maintenance process. The automated pressure data were adjusted accordingly.

Data were lost after August 29, 2017 due to equipment malfunction; the equipment has since been updated. A stage-pressure relation and a stage-discharge rating curve were developed using the 2017 monitoring results after May 27, 2017, and were supplemented with the 2016 data to improve the fit of the stage-pressure relation. An assessment of the goodness of fit of the manual readings to the stage-discharge rating curve yielded a mean difference of 12.4% and a standard error of 1.3%.

Continuous records of stage and discharge values for the monitoring season were generated from PT2x data. Data from April 28, 2017 to May 26, 2017 were excluded from the hydrograph. Flow was highest in May and decreased steadily throughout the summer. The highest calculated discharge rate was 0.47 m3/s on May 27, 2017.

8.3.6 Supplemental Sites

Flow monitoring and/or staff gauge measurements were also collected at supplemental sites including W8 (Northeast Edney Creek Tributary), the Long Ditch, the SERDS, the NW Ditch, Junction Zone Ditch, Joe’s Creek Pipe, the Cut-off Wall Drain and the Main and South Toe Drains at the TSF. Results are presented in Appendix K. These flow measurements from site water management system components are primarily used for verifying the site water balance.


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8.4 Sediment Quality

Sediment traps were deployed in Polley and Quesnel Lake in 2017 by Minnow as part of an ongoing study to understand the post-depositional stability of materials deposited into the aquatic environment following the TSF embankment breach. Overall, the deposition rates in Polley and Quesnel have decreased or remained unchanged. The data and discussion are presented in the Assessment of Sediment Deposition Rates memo in Appendix J.

8.5 Benthic Invertebrates

Benthic community and productivity monitoring was completed in Edney, Frypan, and Hazeltine Creeks, and in Quesnel Lake. The data and discussion are presented in 2017 Polley Lake Frypan Creek Fish Monitoring and the Benthic Community and Productivity memos provided by Minnow in Appendix J.

8.6 Plankton, Chlorophyll a, and Secchi Disk

8.6.1 Plankton and Chlorophyll a

In 2017, chlorophyll a samples in Polley and Quesnel Lake were generally collected two times (ie. June and August) per growing season (Table 8.5). Samples were missed at QUL-120a in June, and QUL-2a and QUL-18 in August due to time constraints and weather conditions. Results are in Appendix L.

Table 8.5 Chlorophyll-a sampling events in 2017

Site name Samples

QUL-ZOO-7 2 21-Jun-17 21-Aug-17QUL-ZOO-1 2 21-Jun-17 21-Aug-17QUL-120a 1 31-Aug-17QUL-2a 1 19-Jun-17QUL-58 3 15-May-17 29-May-17 19-Jun-17QUL-18 1 19-Jun-17P1 2 28-Jun-17 23-Aug-17P2 2 28-Jun-17 23-Aug-17

Sample Date


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Figure 8.3 Chlorophyll results from Polley Lake

Zooplankton samples were also collected twice per growing season (July and August) at the same stations in Polley Lake (P1 and P2), but at different stations in Quesnel Lake. Quesnel Lake monitoring is conducted at three stations historically sampled by Department of Fisheries and Oceans (DFO), so pre- and post-TSF embankment breach results can be compared for both spatial and temporal trends. Station 1 (QUL-ZOO-1) is located in the centre of the West Basin, station 7 (QUL-ZOO-7) is located in front of Horsefly Bay, and station 8 (QUL-ZOO-8) is located at the junction of the North, East, and West Arms. In 2017, zooplankton community samples were collected on June 21, 2017 at ZOO-1 and ZOO-7. Results are in Appendix L. Note no chlorophyll a or zooplankton samples were collected at QUL-ZOO-8 due to high winds creating unsafe conditions for the field crews in June and forest fires limiting visibility and deteriorating air quality in August.

Results from monitoring conducted in 2014 to 2016 were included in the ERA (MPMC, 2017d).

Field methodology is described in Section 4.3

8.6.2 Secchi Disk

During each sampling and profiling event, a secchi depth measurement (Table 8.6) was collected as per Section 6.5 of the CEMP (Appendix A). Secchi depth data are included in Appendix L.

0.1

1

10

100

1000Ch

loro

phyl

l a (µ

g/L)

Polley Lake North Station P1 surface Polley Lake South Station P2 surface


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Table 8.6 Secchi depth measurement events in 2017.


Secchi Depth Measurement Events

P1 E207974 9 P2 E207975 8

B1 E207972 9

B2 E215897 9 B4 n/a 6

QUL-120a E303022

3 QUL-18 E303019

8

QUL-58 E304876

14 QUL-2a E303020

7

All secchi depths measured were within the range of measurements from previous years.

8.7 Fish

Several fish studies were conducted by Minnow in 2017. In Edney Creek, a fish usage and habitat characterization study was conducted, and in Frypan Creek and Polley Lake, habitat assessments and fish community monitoring were completed (Appendix J). Fish tissue sampling was also conducted in Polley and Bootjack Lakes. The data and discussion of the fish tissue memo by Minnow was not finalized at the time of this report submission and will be submitted separately.


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9 Terrestrial Monitoring

Terrestrial environmental monitoring was implemented as per Section 9 of the CEMP (Appendix A). Wildlife observations and notes were recorded throughout the year as per Section 9.1 of the CEMP (Appendix A) and are presented here. Soil, soil invertebrates and vegetation monitoring were ongoing in 2017 and all the results were presented in the HHRA (MPMC, 2017b) and ERA (MPMC, 2017c) in 2017.

9.1 Wildlife Monitoring

The Mount Polley Mine site and surrounding area is home to a wide variety of wildlife including ungulates, carnivores, raptors, water fowl, song birds, mustelids, amphibians and a host of aquatic organisms. With extensive wildlife activity on the mine site, MPMC provides training to all employees regarding management of food waste and bear awareness. This training and information is intended to help keep MPMC employees and the wildlife safe.

To meet requests by the ENV and various stakeholders, to provide valuable data for evaluating the effects of the mine on wildlife, and to monitor wildlife habitat creation through reclamation, the MPMC Environmental Department records wildlife observations and incidents on the mine site. In addition, MPMC maintains a motion triggered wildlife camera, which enables MPMC to capture around the clock wildlife activities. This information is considered valuable for future reclamation and land use planning.

Following the TSF embankment breach, MPMC submitted the PEEIAR (MPMC, 2015a) that included an investigation of the impacts to wildlife. The findings stated that there was no evidence of direct impacts to local populations of larger mammals such as deer, moose or bear, but impacts due to bioavailability of metals was yet unknown. The ERA (MPMC, 2017c) evaluated the possible risks of metal bioaccumulation in various animals. The findings showed that metals were likely to have low bioavailability and a low risk of bioaccumulation. The ERA also compared the frequency of wildlife observations in 2015 to 2016, and noted that the observation of deer, small mammals and birds increased, due to increased forage ability. Ongoing remediation of the impacted areas are providing habitat and food for a variety of mammals and birds, which is an important step to rebuilding the ecosystems.

In 2017, there were 734 recorded wildlife observations; including sightings, scat, and tracks, reported at MPMC (refer to Table 9.1). The observations are separated into “Onsite”, “Offsite” and “Breach Affected” areas and have increased from 2016. They included a wide range of different birds, carnivores, and several insects. It is assumed that the number of reported observations is only a fraction of the actual observations, but suggests regular use of the site by wildlife. Table 9.1 indicates some generic observations such as “Bird”, “Eagle”, and “Deer”, these entries refer to sightings with no positive species identification.

There were no wildlife incidents reported in 2017. Table 9.1 2017 wildlife observations at Mount Polley Mine


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Wildlife Observed # Observed Scat/Tracks Wildlife Observed # Observed Scat/Tracks Wildlife Observed # Observed Scat/Tracks

American Kestrel 2 Arctic Tern 1 American Dipper 3Bald Eagle 8 Beaver 1 Bald Eagle 30Barred Owl 1 Black Bear 9 Barn Swallow 1Barrow's Goldeneye 1 Brown Bear 2 Belted Kingfisher 1Bird 1 Canada Goose 1 Black Bear 22Black Bear 211 Columbia Spotted Frog 1 Blue Heron 3Blue-winged Teal 1 Coyote 1 Bobcat 1Bobcat 4 Fox 1 Brown Bear 2Brown Bear 5 Grizzly Bear 1 Canada Geese 1Bufflehead 2 Lynx 4 Canada Goose 7Canada Goose 4 Moose 5 Chipmunk 2Chipmunk 1 Mule deer 5 Common Merganser 2Common Merganser 1 Otter 1 3 Coyote 3 1Cougar 1 Ruffed Grouse 1 Crossbill 1Cow Moose 1 Sandhill Crane 1 Crow 1Coyote 23 Snowshoe Hare 3 1 Dark headed Junco 2Crow 1 Tadpoles 1 Deer 6 1Deer 14 Unknown 2 2 Duck 3Duck 1 Eagle 2Eagle 2 Eagles 1Elk 3 Frog 1Ermine 3 Golden Eagle 10Fox 1 Goose 1Garter Snake 2 Grizzly Bear 1Geese 1 Grouse 2Golden Eagle 1 Hawk 1Golden Eye Ducks 1 Humming Bird 1Goose 1 Killdeer 6Great Grey Owl 2 Kingfisher 3Grizzly Bear 1 Lesser Scaup Duck 1Grouse 2 Loon 2Hawk 3 Lynx 5Hooded Merganser 1 Malard Duck 1Killdeer 2 Mallard Ducks 1Kingfisher 1 Merlin 1Loon 1 Mermaid 1Lynx 10 1 Moose 9 1Mallard 3 Mountain Blue Bird 3Moose 26 Mule deer 7Mountain Blue Bird 2 Muskrat 1Mule deer 51 Northern Flicker 1Muskrat 2 Northern Pygmy Owl 1Northern Harrier Hawk 2 Osprey 7Osprey 6 Otter 1Otter 2 Owl 1Owl 2 Pacific Tree Frog 1Pacific Tree Frog 1 Polyphemus Moth 1Pine Grosbeak 1 Rainbow Trout 1Porcupine 1 Red Tailed Hawk 7Red Tail Hawk 1 Red-breasted Nuthatch 1Red Tailed Hawk 6 Ruby-crowned Kinglet 2Ring-necked Duck 1 Sandhill Crane 4Sandhill Crane 9 Sapsucker 1Skunk 1 Slug 1Solitary Sandpiper 1 Sparrow 2Stellars Jay 3 Sucker 1Turkey Vulture 2 Swan 4White-crowned Sparrow 1 Toad 1Wolf 1 Tree Swallow 5Yeti 1 Trumpeter Swan 7Unknown 1 1 Trumpeter Swans 1Golden Eye Duck 1 Varied ThrushCoopers Hawk 1 Vole 1Wood pecker 1 Water Fowl 1Squirrel 1 Western Toad 5Wiskeyjack 1 Winter Wren 1Great Horned Owl 1 Wolf 4 1

Yellow-rumped Warbler 1Unknown 5 5Raven 1Yellow Rumped Warbler 1Blue Heron 1Mouse 1Catepillers 1

2017 Wildlife ObservationsOnsite Breach AffectedOffsite


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9.2 Archaeological Resources

First Nations with recognized claimed traditional territory for the Mount Polley Mine are the WLIB and the SCIB. Pre-mining studies noted that the area had low heritage resource potential due to the extensive disturbance in the area from logging and earlier mining projects (Points West Heritage Consulting, 1989).

There were no archaeological or historic sites identified at Mount Polley in 2017.


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10 Reclamation Program

The objectives of the reclamation program are outlined in Section 1.1.1. To achieve these objectives, as outlined in the most recent RCP (MPMC, 2017a), MPMC has established projects at the site to research soil amendments and application methods, re-vegetation, vegetation metal uptake, and passive water treatment. Based on the results of these research projects, larger scale progressive reclamation has been ongoing at Mount Polley since 2010, with two primary benefits:

1. Conducting reclamation during the operating life of the mine reduces the size of disturbed area requiring reclamation at closure, minimizing liabilities.

2. Sites undergoing progressive reclamation can be continually monitored, and reclamation prescriptions modified based on findings. Using this approach, it is anticipated that a refined prescription for meeting reclamation objectives will be developed, and can be applied site wide at mine closure.

An update on 2017 reclamation activities and research projects is included in this section, as well as an updated five-year reclamation plan. Reclamation activities in 2017 were minimal as reclamation resources were primarily allocated to the TSF embankment breach related remediation initiatives in Hazeltine Creek and adjacent to Polley and Quesnel Lakes. Further reclamation information can be found in the MPMC RCP Upate (MPMC, 2017a).

10.1 Reclamation Cost Update

The RCP Update (MPMC, 2017a) is a high level treatment of reclamation and closure activities projected for the End-of-Mine-Life and includes a closure cost update. Updates to the Reclamation Cost estimates were made at the end of 2017 and will be submitted under a separate confidential report to EMPR.

10.2 Stability of Works

10.2.1 Rock Disposal Sites

Examinations of RDS are made in accordance with Section 6.10.1 of the Health, Safety and Reclamation Code for Mines in British Columbia (HSRC). Monitoring of RDS occurs according to the terms and conditions of a variance granted by the EMPR on February 9, 2001. A report on the 2017 RDS inspection, prepared by a Qualified Professional, was submitted to the EMPR on March 31, 2018.

10.2.2 Pit Walls

Pit walls are monitored for stability using high-precision 3-D surveys, radar monitoring, and surface inspections. Pit wall stability is reviewed annually by a third party QP from an engineering services firm. A report on the 2018 pit slope inspection, prepared by a QP, was submitted to the EMPR on March 31, 2018.


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10.2.3 Tailings Storage Facility and Associated Works

MPMC has received authorization to proceed with construction activities at the TSF to a maximum elevation of 970 m under Mines Act Permit M-200, amended June 23, 2016. Construction of the Main Embankment and Perimeter Embankment Buttresses for the 970 m approved design were deemed completed by the Engineer of Record (EoR) in 2016.

MPMC conducted the following TSF related construction activities in 2017:

• April-May 2017 – Embankment construction from 959 m to 966 m at the Corner 1 breach in accordance with the TSF Detailed Design to 970 m.

• June-December, 2017 – Construction of the Corner 1 Buttress for the 970 m stability, in accordance with the TSF Detailed Design to 970 m, making use of the reclaimed tailings from Polley Flats.

o Completion of the 970 m Buttress to occur in 2018, and to include the extension required as a result of the 2016/2017 TSF geotechnical investigation.

• Construction of the Upstream Drain to 964 m elevation

The following inspections occurred at the TSF in 2017:

• Annual Dam Safety Inspection (ADSI), conducted by the EoR in October 2017. Report to be submitted by March 31, 2018.

• Dam Safety Review (DSR) conducted by SRK and occurred in early May. • Annual EMPR Geotechnical inspection occurred in October 2017.

In addition to the physical activities, MPMC also submitted the following reports:

• An as-built report for the Main Embankment and Perimeter Embankment Buttress was prepared by the EoR and submitted to the EMPR on January 31, 2017.

• An as-built report for the 2016 Corner 1 Raise Construction was prepared by the EoR and submitted to the EMPR on March 29, 2017.

• The 2016 ADSI, as required under the HSRC was submitted to the EMPR on January 16, 2017. • Additionally, a TSF geotechnical investigation program was completed in 2016/2017 under the

supervision of the EoR. A factual report on the geotechnical site investigation, as required under the June 23, 2016 Mines Act Permit M-200 amendment, was submitted to the EMPR on January 16, 2017.

• The DSR from SRK was submitted to EMPR on June 28, 2017.

There were no unusual or dam safety related occurrences in 2017. Pond water volume fluctuated between 1.5M and 3.3M m3, with excess water available for discharge through the WTP beginning in June 2018.


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10.3 2017 Reclamation Activities

10.3.1 Reclamation Inspection

On October 4, 2017, EMPR conducted a site visit to carry out a Mines Act environmental and reclamation compliance inspection. An inspection report was issued, including recommendations related to Mines Act Permit M-200 HRSC, and established best practices in environmental management and mine reclamation.

The report included three (3) recommendations and three (3) information requirements that required response from the mine manager. All recommendations have been considered, and a summary is provided in Table 10.1.

Table 10.1 Summary of EMPR reclamation inspection recommendations

Recommendation MPMC Response Recommendation 1: At the stop where the long ditch and the west ditch meet near Bootjack Creek, it was noted that the sediment has been removed from the west ditch, which is a conduit of contact water and has been used previously to transport water from the Springer Pit tailings facility. The sediment was excavated and piled in an adjacent area (not viewed). It is recommended that these materials be characterized to inform selection of an appropriate disposal option that meets reclamation objectives for the site.

MPMC agrees that the material should be characterized and will endeavor to do so to ensure proper disposal.

Recommendation 2: At the Highway to Heaven stop, site personnel discussed the work being conducted by Golder Associates to develop moisture retention curves for the various options being considered for cover materials on the waste dumps and tailings. It is recommended that MPMC evaluate the use of these data for informing the design of soil covers to achieve site-specific land capability (i.e., ecosystems to site series) and end land use targets (i.e., different habitats, etc.).

MPMC has contracted Golder to do this work with the intention of evaluating the data to develop designs and to identify end land use targets.

Recommendation 3: Dust and dust control were discussed briefly during the site tour. Site personnel noted that there have been wind events that have generated substantial dust over the summer. Anecdotal information is that the dust appears to settle out rapidly as it disperses away from the sources on site. This is based on the assertion that the events do not appear to be captured in the dustfall collection devices that are deployed around the site. It is recommended that these events are closely monitored and trigger criteria that reflects the conditions that create the dusting events are established. Dust mitigation plans should be developed to address the conditions that trigger these types of events.

MPMC has a Dust Management Plan in place that addresses these events. The plan has been provided with this response package.


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Information Requirements MPMC Response 1. It was noted during the post-inspection meeting that the site

does have a dust management plan. In the response to this report, please provide the referenced Dust Management Plan and identify the page references that address the recommendations identified in recommendation #3 above.

The Dust Management Plan has been provided with this response package.

2. The sprinkler system used to control dust on the tailings beach was observed from a distance during the inspection. It appears that the area of coverage is only a portion of the exposed surface (though it is possible that the sprinklers may be moved around as needed). Further to the information requirement above, please provide details regarding how dust will be effectively addressed as the area of exposed tailings beach increases over time.

The Dust Management Plan outlines a Plan, Do, Check, Act cycle that provides guidance for managing dust at the TSF. The plan indicates that there are nine (9) whirlybird style sprinklers in place at the TSF. More specifically, theses sprinklers are portable and can be moved around the “beach” area to ensure that moisture is maintained in the exposed tailings.

3. During the inspection, it was stated that biosolids importation to the mine site may resume in the future and these materials could be used for large scale reclamation purposes. At least 30 days prior to transporting these material to site, please provide notification to the Chief Inspector of intent to import biosolids to the mine. The notification must include a plan and schedule for use of the materials on site, as well as the monitoring program that will be implemented to ensure that any risks to human health or the environment are identified and mitigated. This program should include vegetation tissue, as well as soils, groundwater and surface water.

MPMC will notify the EMPR at least 30 days prior to transporting biosolids to the mine. This notification will include a plan and schedule for use of the materials. All environmental monitoring is included in the Comprehensive Environmental Monitoring Plan submitted under EMA Permit 11678.

The conclusion of the report stated the following: “The October 4, 2017 reclamation inspection provided a good overview of the status of the reclamation and environmental protection activities at the mine site. Recommendations provided pertain to disposal of sediment excavated from the contact water collection system, design of soil covers to promote restoration of ecosystems and habitats, and dust management planning. Information requirements include dust mitigation plans, in particular considering expansion of the TSF beach, and monitoring and use of biosolids for reclamation purposes.”

10.3.2 Progressive Reclamation

Progressive reclamation completed to date is detailed in Table 10.2. Further information on progressive reclamation at Mount Polley Mine is summarized in the following sections. Table 10.2 summarizes the area disturbed and reclaimed in 2017, and fulfills the EMPR requirements for Table 1.


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Table 10.2 Progressive reclamation completed at Mount Polley Mine as of December 31, 2017

10.3.2.1 Waste Dumps

In 2017, approximately 8,505 lodgepole pine, 6,360 Sitka alder, 255 prickly rose, 255 paper birch, 1060 black cottonwood, 250 saskatoon and 255 Scouler’s willow were planted on Phase 1 and 2 on the North Bell Dump (NBD). Initial walkthrough assessments (informal) indicate serious drought damage on the plantation and future success of the plantation is expected to be limited. Monitoring is ongoing.

Reclamation of ~ 0.9 ha was initiated in two locations on the east side of the North Bell Dump in 2017. The work included re-contouring and soil delivery. Completion of the work is pending.

No new reclamation work was completed on the North East Zone (NEZ) Dump, Boundary Dump, or East RDS in 2017. Monitoring of past reclamation is ongoing.

10.3.2.2 Watercourse Reclamation

No watercourse reclamation was conducted in 2017.

10.3.2.3 Pit Reclamation

No pit reclamation was conducted in 2017. The Bell Pit, Pond Zone Pit, and Southeast Zone (SEZ) Pit have been back-filled by waste dumps and will not require reclamation.

10.3.2.4 TSF Reclamation

No reclamation was conducted at the TSF in 2017.

10.3.2.5 Road Reclamation

No road reclamation was conducted in 2017.

2017 Total 2017 Total 2017 Total 2017 Total 2017 Total2a, 2b1, 2b2 0.00 5.13 0.00 5.13 0.00 5.13 0.00 5.13 0.00 5.13Beside 2a/2b 0.00 2.47 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00Parcels 1 - 10 0.00 9.45 0.00 11.59 0.00 11.59 0.00 11.59 0.00 11.59South Triangle 0.00 1.30 0.00 1.30 0.00 1.30 0.00 1.30 0.00 1.30Phase 1 0.00 2.21 0.00 2.21 0.00 2.21 0.00 2.21 2.21 2.21Phase 2 0.00 2.87 0.00 2.87 0.00 2.87 0.00 2.87 2.87 2.87Metro Van Research 1 0.00 2.81 0.00 2.81 0.00 1.87 0.00 2.34 0.00 2.34Wrap Around Toe 0.00 0.00 0.00 2.20 0.00 2.20 0.00 0.00 0.00 0.00Beside Research 1 0.00 4.76 0.00 1.99 0.00 0.00 0.00 0.00 0.00 0.00Metro Van Research 2 0.00 2.00 0.00 2.00 0.00 1.33 0.00 1.66 0.00 2.00Beside Research 2 0.00 2.73 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00Beside BJ FSR 0.90 0.90 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Boundary Zone Dump 0.00 4.70 0.00 4.70 0.00 0.00 0.00 0.00 4.70 4.70Above Access Road 0.00 3.42 0.00 4.06 0.00 4.06 0.00 0.00 2.75 2.75Highway to Heaven 0.00 11.53 2.89 9.47 2.89 6.58 0.00 0.00 9.47 9.47Tree Plots 0.00 2.31 0.00 2.31 0.00 2.31 0.00 1.20 0.00 2.31Above WHR 0.00 1.81 0.00 1.81 0.00 1.81 0.00 0.00 0.00 0.00Below Helipad 0.00 1.53 0.00 1.53 0.00 1.53 0.00 1.53 0.00 1.53

South Till Borrow 0.00 23.25 0.00 0.00 0.00 14.75 0.00 12.00 0.00 0.00TOTAL 0.90 85.18 2.89 55.98 2.89 59.54 0.00 41.83 22.00 48.20

Re-contoured (ha) Seeded (ha) Fertilizer/Biosolids (ha) Tree-Planted (ha)Soil/Till Applied (ha)Area Parcel

NEZ Dump

Waste Haul Road

East RDS

NBD


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10.3.2.6 Treatment of Structures and Equipment

No site structures or equipment were salvaged or disposed of in 2017.

10.3.2.7 Securing of Mine Openings

There was no sealing or securing of any mine entrances in 2016; both portal and escape ways remain open and in use.

10.4 2017 Reclamation Research Update

Limited reclamation research was conducted in 2017. Ongoing biosolids reclamation research was summarized in the paper Conifer Seedling Establishment on a Rock Disposal Site at the Mount Polley Mine to Assess Competitive Effects of Various Herbaceous Groundcovers when Using Biosolids as a Soil Amendment (Appendix M). A ground cover assessment was completed on the research trials parcels 1-6 in the summer/fall of 2017, which is not included in this report but will eventually be included in the paper.

Information on ongoing and past reclamation research can be found in MPMC Annual Environmental and Reclamation Reports from years 2010 to 2015. Further information can be found in MPMC RCP Update January 2017 (MPMC, 2017a).

10.4.1 Native Species Establishment

Native species establishment is a target for all current and future reclamation at Mount Polley Mine. Seedlings of native species have been propagated and planted at the site utilizing the services of commercial nurseries. The custom MPMC Native ground cover seed mix consists of native species Table 3.3. Also, site preparation surface roughening techniques such as ripping, mounding and windrowing are utilized in part to assist in seed recruitment from adjacent woodlands. Development of a native seed collection program is being considered. Native species establishment research has been initiated on site in a number of research trials and progressive reclamation areas. While no new results are available from 2017, growth of these trials continues and monitoring will continue in the future.

10.4.2 Biosolids

In 1999, the ENV issued MPMC a permit to import biosolids from the Greater Vancouver Regional District (now Metro Vancouver) for the purpose of mine site reclamation (EMA Permit 15968). After initial receipt and stockpiling of the biosolids shipments in 2000, the program was suspended due to the temporary closure of the mine; biosolids shipment recommenced in 2007. In 2014, EMA Permit 15968 was amended to include:

• An increase in the maximum rate of land application from 150 dry tonnes (dt)/ha to 165 dt/ha; • An increase in the maximum cumulative discharge from 90,000 dt to 99,000 dt;


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• Revised references to MPMC land claims and an updated site plan; and • The allowance of two designated storage facilities.

Currently there is only one biosolids stockpile on site, located near the TSF. Table 10.3 provided by Metro Vancouver, summarizes biosolids deliveries and applications at Mount Polley from 2000 to 2014. No biosolids were used or stockpiled on site in 2017. As no deliveries were made in 2017, no Metro Vancouver biosolids were assessed for compliance with EMA Permit 15968 requirements or compared to the Organic Matter Recycling Regulation criteria for Class A biosolids.

Table 10.3 Metro Vancouver biosolids deliveries and applications at Mount Polley (2000 – 2014)

10.4.3 Vegetation Metal Uptake

The impact of vegetation metal uptake of tailings from the TSF embankment breach was evaluated in the HHRA and ERA completed in 2017. Conclusions from the risk assessment reports foundd that the hazard to human health is considered very low (MPMC, 2017b) and that the “presence of residual metals in the soil are not likely to prevent the reintroduction of diverse, functional, self-sustaining and inter-dependent plant

Mt Polley Inventory, Updated: Oct. 28, 2014

Annacis Lulu Total (wt) Total (dt )

10,754 10,754 25814,641 4,641 1114

7,101 124 7,225 216016,136 42 16,178 43671,206 1,206 3389,664 9,664 2706

3,875 3,875 11635,058 5,058 1416

1,060 1,060 2971,482 1,482 415

2013 Deliveries: Tree Trial Plots (Sept. 28 - Oct. 6) 960 960 269706 706 198

Delivered 2000-to-present 47,247 15,561 62,808 17022

Annacis Lulu Total (wt) Total (dt )tree research plots (circa 2000/01) 234 234 56

NEZ - 2008 3,875 3,875 1,163 North Bell Roadside Slopes (Areas 1 - 10) - 2011 11.6 122 5,058 5,058 1,416

North Bell (Areas 11 - 19) - 2012 5.1 140 2,542 2,542 712 North Bell Tree Trial Plots (Plots 2-6) - 2013 2.3 104 960 960 269

North Bell Tree Trial Plots (Plots 8-12) - 2014 1.7 118 706 706 198 -

13,141 234 13,375 3,813 34,106 15,327 49,433 13,209

Stockpile Location Delivery Date Biosolids Delivered

Tailings Storage Facility Stockpile(Area 1)

2000/01 inventoryFeb 7 - Nov 2, 2007Aug 5 - Nov 1, 2009

Jan 1 - Nov. 12, 2010Apr 4 - 14; July 4, 2011Apr 25 - Sept. 4, 2013

NEZ Sep 28 - Nov 19, 2008Apr 15 - May 29, 2011

Biosolids Utilized

CONFIRMED - APPLIED/USED to date

North Bell

2012 deliveries: MPMC "Area 2" (May 30 - June 17)2012 deliveries: MPMC "Area 1" (June 18 - July 31)

2014 Deliveries : Tree Trial Plots (May 21 - 27)

Carry Over (at TSF)

Applications

Site ID ha rate(dt/ha)


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community” (MPMC, 2017c). Details and results are found in the HHRA (MPMC, 2017b) and the ERA (MPMC, 2017c).

10.4.4 Passive Treatment

The Anaerobic Biological Reactor (ABR) was a pilot passive water treatment system constructed at the Mount Polley site in 2009 in partnership with the University of British Columbia and Genome BC. In 2015, the ABR was decommissioned in preparation for buttressing of the TSF Main Embankment. The objective of the ABR was to reduce elevated parameters in mine effluent through microbial activity to concentrations appropriate for discharge into the receiving environment.

Monitoring results (refer to pervious Annual Environmental and Reclamation Reports) indicate that the ABR was capable of reducing metal concentrations in TSF toe drain water to below BCWQGs for protection of aquatic life for all parameters except sulphate. Research indicated the primary causes for the low levels of sulphate reduction to be a lack of dissolved metals for sulphate to bind to and insufficiently anaerobic conditions during summer months.

In 2016, MPMC engaged Contango Strategies Ltd. (Contango), and Golder, to initiate further research work into the feasibility of passive and semi-passive water treatment at the Mount Polley Mine site. As stated in the RCP 2017 Update (MPMC, 2017a), “a passive or semi-passive system is the preferred option for water treatment during closure/post-closure; however, optimization through bench- and pilot-scale testing is required to address uncertainties and to optimize the design of a full-scale system” or systems. In addition, where technically achievable, the Mine intends to initiate passive and/or semi-passive treatment during operations.

The work initiated in 2016 is intended to identify and characterize the feed water chemistry and flows of various locations on site that would be most suitable for passive treatment, and to identify sites that could be (a) discharged directly with little or no treatment, (b) suitable pilot sites for simple passive treatment systems, and (c) potential pilot sites for semi-passive treatment. Ideally, individual flows for various Mine water sources will be individually assessed in order to tailor treatment technologies to specific sources and their characteristic chemistry. Also, wherever possible, passive treatment systems (if shown to be feasible) will be designed to make use of materials available on site or from the local area (MPMC, 2017a).

Passive treatment research is being advanced in parallel across multiple fronts. Key passive treatment initiatives being investigated include use of biochemical reactors (BCR), constructed wetland treatment systems (CWTSs) and in situ pit lake treatment. Summaries of the work completed to date and future plans are provided below, with further detail provided in the Treatment Works and Source Control Optimization: Progress Report #1 (MPMC, 2017g) submitted under Section 2.9 of EMA Permit 11678.

BCR

Work is ongoing with Golder to explore the potential for use of BCRs at the Mount Polley site. This work complements the previous ABR research, and includes evaluation of potential passive


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treatment ‘train’ configuration (and the role of a BCR within it). As summarized in the Long Term Water Management Plan (LTWMP) Technical Assessment Report (TAR) (Golder, 2016c) and RCP (MPMC, 2017a) work conducted in completing the site selection screening, COC identification and technology assessment and preliminary implementation scheduling supports advancing the concept of BCRs to the bench-scale phase. Work in 2018 is planned to include bench-scale testing of various combinations of BCR substrate, inoculums and influent water. Results of the bench-scale testing will inform the advancement to, and subsequent design off pilot-scale works.

CWTSs

Work is ongoing with Contango to explore the potential for use of CWTSs at the Mount Polley site. Following initial site visits in 2016 and initial review of the information contained in the RCP 2017 Update, Contango completed a “Phase 1 Feasibility Assessment”. Findings of the assessment determined, among other things, that the water chemistry at the Mount Polley site is relatively benign, and that passive treatment is conceptually and theoretically possible.

Advancing from the feasibility assessment, and utilizing information contained in the RCP 2017 Update, Contango produced a technical memorandum in 2017 identifying Contaminants of Potential Concern (COPCs) for predicted closure and post-closure water quality characteristics and identifying potential treatment mechanisms for each constituent.

Similar to the findings of the work conducted relative to BCRs, work completed to date regarding CWTSs supports the advancement to bench-scale testing. Work in 2018 is planned to include (a) conceptual design and sizing of CWTSs for closure and (b) bench-scale testing of various substrates and water chemistries. Results of the bench-scale testing will inform the advancement to, and subsequent design off pilot-scale works.

In situ Pit Lake Treatment

Work is ongoing with Golder to explore the potential for use of in situ pit lake treatment at the Mount Polley site. Informed by the results of the water quality modelling included in the LTWMP TAR (Golder, 2016c), the primary target of the in situ pit treatment investigation is selenium reduction. This treatment technology relies on the same anaerobic microbial reduction process as active and passive biological treatment, and involves amending surface water to promote this anaerobic reduction.

A desktop study conducted in 2017 (MPMC, 2017a) supported the feasibility of the treatment methodology, and recommended advancing to bench-scale testing. Work in 2018 is planned to include bench-scale testing of various combinations of carbon amendments, inoculums and influent water. Results of the bench-scale testing will inform the advancement to, and subsequent design off pilot-scale works.

Work is ongoing to meet the requirements of the EMA Permit 11678 and reclamation goals of MPMC.


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10.5 Five Year Reclamation Plan

Table 10.4 outlines Mount Polley’s five year progressive reclamation plan, and the reclamation sites are shown in Figure 4-1 of the RCP. MPMC is currently focusing reclamation efforts on the rehabilitation of Hazeltine Creek and areas impacted by the TSF embankment breach. Ongoing monitoring will continue on progressive reclamation sites and research projects, and the five year reclamation plan may evolve based on the findings.


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Table 10.4 Five year progressive reclamation plan

Site Parcel(s) Area End Land Use Objectives Soil Stockpile Source Volume (m3)

Application Depth(cm)

Ammendments Grass Seed Mix3 Shrub & Deciduous Tree Planting Conifer Tree Planting Re-Contour Soil Application Soil Ammendment

Application

Coarse Woody Debris

Applicaiton

Grass Seeding

Shrub & Deciduous Tree Planting

Conifer Planting

North Bell Dump Parcels 1-10 11.59 Wildlife, forestry Wight Till 10,600 20 Biosolids (122 dt/ha)

Native grasses (30 kg/ha)(hydroseeded with fibre mulch, except southern-most Parcel 10 hand seeded at 35 kg/ha)

Black cottonwood - 60 sphPaper birch - 34 sphTrembling aspen - 34 sphSitka alder - 172 sphSaskatoon - 34 sphPrickly rose - 34 sphScoulers willow - 79 sphSoopolalie - 100 stem trial plot

Lodgepole pine - 1075 sphDouglas fir - 451 sphWestern red cedar - 54 sphHybrid spruce - 54 sph

Consider underplanting with later successional species in future.

2011 2011 2011 2011 2011 2013 - poor survival2014 - re-plant 2014

South Triangle 1.30 Wildlife, forestrty North Bell Dump Till 1,733 30 18-19-18 Fertilizer (75 kg/ha) Native grasses (35 kg/ha)(hydroseeded with fibre mulch)

2013Black cottonwood - 1000 sphSitka alder - 800 sph

2014Soopolalie - 100 stem trial plot

Lodgepole pine - 1400 sphDouglas fir - 600 sph


2011 2011 2011 - 2011/2012 2013/2014 2014

Phase 1 2.21 Wildlife, forestry North Bell Dump Till 3,920 20 Biosolids (138 dt/ha) Native grasses/forbes (35 kg/ha)(hand seeded)

Black cottonwood - 200 sphPaper birch - 100 sphTrembling aspen - 100 sphSitka alder - 200 sphSaskatoon - 100 sphPrickly rose - 100 sphScoulers willow - 200 sph



2012 2012 2012 - 2012 TBD TBD

Phase 2 2.87 Wildlife, forestry North Bell Dump Top 4,680 20 Biosolids (135 kg/ha) Native grasses + lupine (35 kg/ha)(hand seeded)




2012 2012 2012 - 2012 TBD TBD

Metro Van Research Parcel 1 2.81 Wildlife, forestry North Bell Dump Till 4,680 20 Biosolids (107 dt/ha) (on 2.34 ha)

1) No seed2) Forbes mixture (75 g/ha fireweed, 1 kg/ha lupine, 113 g/ha Dryas drummondii, 4.9 kg/ha june grass, yarrow, pearly everlasting mix)3) Fireweed (75 g/ha)4) No seed5) Native grasses/forbes (5kg/ha)6) Native grasses/forbes (10 hg/ha)

Black cottonwood - 200 sphPaper birch - 50 sphTrembling aspen - 50 sphSitka alder - 200 sphSaskatoon - 50 sphPrickly rose - 50 sphScoulers willow - 50 sphHuckleberry - 50 sph



2012 2013 2013 - 2014 2014 2014

Wrap Around Toe 2.20 Wildlife North Bell Dump Till 14,418 6 None Native grasses (~15 kg/ha)(hand seeded) - 2012 - - 2012

Beside Research 2.00 Wildlife, forestry Direct Placement:SEZ Stripping 4,000 20 None

Monitor natural growth from direct placement.Native grasses/forbes or forbes as needed. (application rate to be determined)




2012 2013 - Already in soil TBD TBD TBD

Metro Van Research Parcel 2(in Beside Phase 2 parcel 4.73 ha area)

2.00 Wildlife, forestry North Bell Dump Top 4,000 20 Biosolids (107 dt/ha)

1) No seed2) Forbes mixture (75 g/ha fireweed, 1 kg/ha lupine, 113 g/ha Dryas drummondii, 4.9 kg/ha june grass, yarrow, pearly everlasting mix)3) Fireweed (75 g/ha)4) No seed5) Native grasses/forbes (5kg/ha)6) Native grasses/forbes (10 hg/ha)

Black cottonwood - 200 sphPaper birch - 50 sphTrembling aspen - 50 sphSitka alder - 200 sphSaskatoon - 50 sphPrickly rose - 50 sphScoulers willow - 50 sphJuniper - 90 stem trialSoopalalie - 90 stem trial

Lodgepole pine - 1090 sphDouglas fir - 758 sphh


2012 2014 2014 - 2014 2015 2015

Wrap Around 5.14 Wildlife, forestry North Bell Dump Till 10,280 - 12,850 20 - 25 Biosolids2 - - - TBD TBD TBD TBD TBD TBD TBD

Waste Haul Road Heli Pad Area 1.53 Wildlife, forestry Old Cariboo Stockpile/Springer Pit 3,825 28 18-19-18 Fertilizer (170 kg/ha) Aggressive seed mix (26 kg/ha)

(hydroseeded) Monitor natural vegetation ingress

Douglas fir - 330 stemsPlanned:Lodgepole pine - 1260 sphDouglas fir - 540 sph


- 2013 - Already in soil 2014 -2015

Rest - TBD

Above WHR (Pond Zone) 1.81 Wildlife, forestry Old Cariboo Stockpile/Springer Pit 5,456 30 None Native grasses/forbes (22 kg/ha) Monitor natural vegetation ingress



- 2013 - Already in soil 2013 - TBD

East RDS Highway to Heaven 11.52 Wildlife, forestry

2014:Direct Placement: Cariboo Ore Stockpile, WX Zone Stripping

2015:Highway to Heaven

2014:26,700

2015:8,200

40 None Native grasses/forbes (30 kg/ha)




2014 - 9.47 ha2015 - 2.05

2014 - 6.58 ha2015 - 4.94 ha - Already in soil 2014 2015 2016

Tree Plots4 2.13 Wildlife, forestry Bell Pit Stockpile Not Calculated 0 - 65

Amendment Tested:Fertilizer (RTI Bio Pack's, 10g/bag)Biosolids (50 - dt/ha)Tailings (20cm)

Domistic grasses (20kg/ha - 40 kg/ha)Native grasses/forbes (40 kg/ha) - two different mixtures

- Lodgepole pine - 1400 sphDouglas fir - 600 sph 2000 1998 -

2000 1998 - 2000 - 1998 - 2000 - 1998 - 2000

Above Access Road 3.78 Wildlife, forestry

Direct Placement:TSF Rd Stripping (Bootjack Creek), Cariboo Ore Stockpile, WX Zone

9,000 25 None

~ 0.75 kg/ha lupine~2 kg/ha june grass, yarrow, pearly everlasting mix~35 g/ha Fireweed(~1 ha on eastern side only)Remaining area: Native grasses/forbes (30 kg/ha)




2011 2014 - Already in soil 2014 TBD TBD

44.42 Wildlife, forestry, livesSouth Till Borrow 65,340 20 - - - - TBD - TBD TBD TBD TBD TBD

23.95 Wildlife, forestry, livesSouth Till Borrow N/A N/A Biolids - 12.00 ha Unknown

NEZ Dump Parcel 2 (a/b) 5.13 Wildlife, forestry Wight Till 20,000 402a: fertilizer (238 kg/ha)2b1: biosolids2b2: fertilizer (71 kg/ha), biosolids

Native grasses/forbes (handseeded)2a: 45 kg/ha2b: 34 kg/ha

Paper birch - 100 sphTrembling aspen - 100 sphBlack cottonwood - 200 sphSitka alder - 100 sphsaskatoon - 100 sphwood rose - 100 sphWillow live stakes - 40 sph

Lodgepole pine - 1300 sphDouglas fir - 700 sph 2010 2010 2010 - 2011 2012 2012

North Triangle 11.73 Wildlife, forestry Wight Till 52,300 45 Biosolids2 - - - TBD TBD - Already in soil TBD TBD TBD

Boundary Zone Boundary Dump 4.70 Wildlife, forestry PAG Dump Stripping 12,000 28 None 2011 2014 - Already in soil

Below Access Road 3.10 Wildlife, forestry PAG Dump Stripping 6,200 - 7,750 20 - 25 None - - - TBD TBD - Already in soil TBD TBD TBD

Notes:

1) Blank cells indicate prescription to be determined based on most recent findings from ongoing research and progressive reclamation.

2) Base biosolids application rate on lastest results from trials and progressive reclamation.

3) Native grasses/forbes: mountain brome, native red fescue, Rocky Mountain fescue, wheat grass - blue bunch, blue wild rye, june grass, tickle grass, fireweed.

Native grasses: mountain brome, native red fescue, Rocky Mountain fescue, wheat grass - blue bunch, blue wild rye.

Aggressive seed mix: dahurian wildrye, slender wheatgrass, perennial ryegrass, timothy

4) Refer to summary reports on the tree plots for detailed information on the treatment units and research design

Monitor growth from direct placement and natural ingressMonitor growth from direct placement and natural ingress (monitor invasive species establishment)

ScheduleSite Specifications

Monitor natural vegetation ingress

Revegetation1Soil

TBD - monitoring ingress

South Till Borrow Soil Stockpile/Old Borrow


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11 Mining Program

11.1 Surface Development to Date

At the end of 2017, the total disturbed area at the Mount Polley Mine site was 1,239.75 ha. Discussion of disturbed areas in this report does not include areas disturbed due to the TSF embankment breach. Table 12.1 provides a breakdown of disturbed areas by mine component. These areas are shown on the site facilities map in the RCP (MPMC, 2017a). Concurrently with surface development, progressive reclamation is ongoing. Table 11.1 provides the areas re-sloped, seeded, fertilized, and re-vegetated in 2017 and total reclamation to date. A detailed discussion of site reclamation from 2017 is provided in Section 10.

Table 11.1 Mount Polley Mine site existing and projected disturbance

Area End Land Use Existing Area

Closure Area (if change)

Reclaimed Area

Lake Area

Reclamation Area

(ha) (ha) (ha) (ha) (ha) Dumps Bell Dump N/A Boundary Dump Wildlife/Forestry 4.85 4.70 0.15 East RDS Wildlife/Forestry 51.37 5.06 46.31 Highway to Heaven Wildlife/Forestry 16.24 9.47 6.79 NEZ Dump Wildlife/Forestry 22.92 5.13 17.79 North Bell Dump Wildlife/Forestry 62.47 62.07 22.31 39.76 SERDS Wildlife/Forestry 109.97 110.27 106.21 Temporary NW PAG Stockpile Wildlife/Agroforestry 80.48 77.93 74.19

Dumps Subtotal 348.32 345.67 46.67 - 291.20 Pits Boundary Pit Pit Walls/Lake 12.26 19.41 2.74 5.28 C2 Pit N/A Cariboo Pit N/A Pond Zone Pit N/A TSF Quarry Pit Walls/Lake 10.80 10.80 SEZ Pit N/A Cariboo-Springer Pit Pit Walls/Lake 145.77 163.57 49.70 90.54 Wight Pit Pit Walls/Lake 40.33 14.61 22.95 Pits Subtotal 209.16 234.11 - 67.05 129.57 Stockpiles #1 Stockpile Wildlife/Forestry 10.76 10.06 10.06 Biosolids Wildlife/Forestry 2.92 2.92 High Ox Stockpile Wildlife/Forestry 10.57 10.57 Mount Polley Soil Wildlife/Forestry 4.03 4.03


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NEZ Soil Wildlife/Forestry 9.46 9.46 Cariboo Ore Stockpile Wildlife/Forestry 11.00 11.00

Pond Zone Wildlife/Forestry 2.83 2.83 SERDS Soil Stockpile Wildlife/Forestry 12.76 12.09 12.09 Tailings Soil Wildlife/Forestry 2.95 2.95 Stockpiles Subtotal 67.28 65.91 - - 65.91 Roads Boundary/Wight Pit Connector Road Wildlife/Forestry 1.64 - - 1.64

Crusher Road Wildlife/Forestry 2.28 2.28 Mill/TSF Connector Road Wildlife/Forestry 17.20 17.20

New Access Road Wildlife/Forestry 26.89 26.89 Old Mine Access Road (Bootjack) - Mine Component

N/A

Old Pond Zone Road N/A Old Tailings Haul Road Wildlife/Forestry 12.08 12.08

Old Wraparound Road Wildlife/Forestry 11.10 11.10

Ore Switchback Road Wildlife/Forestry 10.50 10.50

Polley Lake Access Road Access Road 0.71 0.71

Waste Haul Road Access Road 59.21 103.72 103.72 Wight Pit Haul Road Access Road 14.42 14.42 Wight Pit/Tailings Road Access Road 16.83 16.83

Roads Subtotal 172.86 217.37 - - 217.37 TSF Corner 4 to Corner 5 Wildlife 11.49 11.49 Corner 4 to Corner 5 Light Duty Access Road

Access Road 6.61 6.61

East Till Borrow Wildlife/Agroforestry 13.98 13.98 Hazeltine Discharge Pipe Grade Wildlife/Forestry 3.68 3.68

Main Embankment Access Road 28.40 28.40 Perimeter Embankment Access Road 44.87 44.87

South Embankment Access Road 9.10 9.10 Southeast Till Borrow Wildlife/Agroforestry 26.27 23.95 2.32


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11.2 Underground Mining Program

Approximately 25,000 tonnes of ore were extracted from the underground mine in 2017 from Halo 2. This completes all current mining and as of May 2017, the underground went into care and maintenance. A drill program consisting of 6,000 m, which began in December 2016, was completed in February 2017. An Economic Potential Assessment based on the drilling results was completed in August 2017.

Tailings Pipe Grade N/A TSF - South and Main Ponds Wildlife/Agroforestry 10.83 10.83

TSF - Southwest Pond Wildlife/Agroforestry 3.83 3.83

TSF Surface Wildlife - Forested Wetland 214.09 32.11 181.98

TSF Subtotal 373.15 373.15 23.95 32.11 317.09 Miscellaneous Geology Area Wildlife/Forestry 2.80 2.80 Helipad Wildlife/Forestry 3.12 1.53 1.59 Hydro Line Wildlife/Forestry 3.17 3.17 Long Ditch Watercourse 7.46 7.46 Mill Area Wildlife/Forestry 23.80 23.80 Northwest PAG Ditch N/A

Old Dispatch N/A Old Orica Sites Wildlife/Forestry 1.73 0.76 0.76 South SERDS Ditch Watercourse 2.61 0.40 0.40 Warehouse Area Wildlife/Forestry 14.36 14.36 West Ditch Watercourse 9.93 9.93 Miscellaneous Subtotal 68.98 65.80 1.53 - 64.27

TOTAL 1,239.75 1,302.01 72.15 99.16 1,085.41


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11.3 Projected Surface Development

The projected closure disturbance area for the four-year mine plan is 1,302.01 ha, which is a total increase of 1.09 ha over the existing (December 31, 2017) Mine Site footprint. This increase in disturbance is the result of the development of components under the authorized mine plan, including pits (continued mining), SERDS and Temporary NW PAG Stockpile development (material placement), and road infrastructure (i.e., the Tailings Dam Access Road; TDAR).

The projected changes in disturbed areas with the closure footprint are outlined in Table 12.3. Existing and projected disturbance can be found in Table 12.1. Further information on projected surface development can be found in RCP (MPMC, 2017a).

Table 11.2 Changes in disturbed areas with closure footprints

Area Existing Area (ha)

Closure Area (if changed) (ha) Delta Description

Dumps

North Bell Dump 62.47 62.07 -0.40 Cariboo-Springer Pit Expansion SERDS 109.97 110.27 0.30 Final resloped footprint Temporary NW PAG Stockpile

80.48 77.93 -2.55 Final resloped footprint

Pits

Boundary Pit 12.26 19.41 7.15 Boundary Pit Development Cariboo-Springer Pit 145.77 163.57 17.80 Cariboo-Springer Pit Development Stockpiles

#1 Stockpile 10.76 10.06 -0.70 Cariboo-Springer Pit Expansion SERDS Soil Stockpile 12.76 12.09 -0.67 SERDS Expansion Roads

West Haul Road 59.21 103.72 44.51 Assumes completion of TDAR; if not, no additional disturbance.

Miscellaneous

Old Orica Sites 1.73 0.76 -0.97 TDAR Construction (West Haul Road) South SERDS Ditch 2.61 0.40 -2.21 TDAR Construction (West Haul Road)

11.4 Salvaging and Stockpiling of Surficial Materials

11.4.1 Volumes and Storage Locations

As per the MPMC Soil Management Plan in the RCP (MPMC, 2017a), MPMC tracks volumes and locations of soil stockpiles and has a sampling program in place to characterize soil suitability for reclamation. In 2017 the following transfers were completed:

• 1,487 m3 was removed from the access to the Cariboo Pit to the SEZ-1 Stockpile to allow for re-


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orientation of the Cariboo Pit access road. • 14,367 m3 was removed from the new SERD Access Road to the Cariboo Stockpile

Active stripping at the TSF in advance of expansion of the Perimeter Embankment Buttress work was completed by the end of 2017. Recovered soil from the Perimeter Embankment Buttress work was used in the remediation of the tailings breach affected areas adjacent to the buttress. Table 11.4 summarizes the quantities of soil at the mine site and meets the requirements for EMPR reporting for ‘Table 5’.

Table 11.3 MPMC Soil Inventory as of Dec. 31, 2017.

Stockpile Name Location Soil Volumes (m3) TSF Corner 1 - Windrow TSF Corner 1 5,100 Upper Plug Acces Road (PAR) - Windrow

Along upper PAR 1,700

Plug - Stockpiles Polley Lake Plug 127,017 Perimeter Pond - Stockpile Bottom of Corner One (near old Perimeter

Pond) 4,700

Till Borrow - Windrow North of (Perimeter) Till Borrow 42,800 Perimeter Embankment - Windrow

Edge of Perimeter Embankment 3,800

Main Embankment - Stockpile SE of Main Embankment 94,900 South Till Borrow - Stockpile 1 NW stockpile in South Till Borrow 11,600 South Till Borrow - Stockpile 2 S stockpile in South Till Borrow 65,300 South Till Borrow - Stockpile 3 NE stockpile in South Till Borrow 9,600 Gavin Lake Road - Windrow Gavin Lake Road (along South/Main

Embankment) 24,200

TDAR - Windrow Adjacent to TDAR 43,500 Tailings Reclaim Road - Windrow Tailings Reclaim Road 44,300 Cariboo Stockpile - Stockpile Below Cariboo Stockpile 33,967 Mill Site - Stockpile East of Mill/Admin Building (includes

berms) 10,700

Access Road km 11.5 - Stockpile Across from NBD Reclamation Parcels 1 - 10 8,200 Access Road km 12 - Stockpile S-SW of Mount Polley Peak (by km 12 on

Access Rd) 83,700

East RDS - Stockpile Top of East RDS 58,500 Leach Pad - Stockpile Top of East RDS 4,800 Highway to Heaven - Windrow Highway to Heaven Access Road 21,500 NEZ Dump Top - Stockpile Top of NEZ Dump 6,500

25,000 NEZ Dump Lower - Stockpile Off Wight Pit Haul Road 71,300 Wight Pit Till - Stockpile Bottom of Wight Pit Haul Rd 135,100 Wrap Around Road - Windrow Wight Pit - TSF Connector Road (below NEZ

Dump) 101,600

North Bell Dump Till - Stockpile North Bell Dump 164,000 North Bell Dump Top - Stockpile Top of North Bell Dump 8,500


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Springer North Between North Bell Dump and Springer Pit 20,000 Northwest Sump Road - Windrow Northwest Sump Road 7,500 PAG Dump - Windrow Below PAG Dump 39,300 SEZ 1 - Stockpile Top of Old Pond Zone Pit 108,687 SEZ 2 - Stockpile Top of SERDS (near SEZ - 1) 14,000 SEZ-3 Below Co-mingling Project 65,700 SEZ-4 Below Co-mingling Project / SERDS 22,600 SERDS - Stockpile Below SERDS Dump 58,000 Old TSF Haul Road Along old TSF Haul Road (SERDS) 27,200 Lower SERDS - Stockpile 1 Below SERDS Dump 30,900 Lower SERDS - Stockpile 2 Below SERDS Dump 28,200 Lower SERDS - Stockpile 3 Below SERDS Dump 140,100 TDAR Sand/Soil Stockpile Tailings Dam Access Road 46,425

Total: 1,820,496

Further details regarding soil balance and planned usage during progressive and final reclamation can be found in RCP (MPMC, 2017a).

11.4.2 Soil Stockpile Inspections

Several soil stockpiles on the North Bell Dump were inspected in 2017. The inspections were done in advance of reclamation activities on adjacent parcels. Stockpiles were assessed for erosion and vegetative cover. Any stockpiles where erosion or low vegetative cover was observed were added to the bi-annual (spring and fall) seeding list to be seeded with MPMC’s custom native grasses and forbes blend. Percent invasive species was assessed and documented as part of ongoing management of invasive plant species Mount Polley Mine site; refer to Section 3.3 for more information on Mount Polley’s Invasive Plant Management Plan (Appendix G).

11.4.3 Soil Stockpile Quality

Stockpile sampling and characterization did not occur in 2017. A stockpile sample program was undertaken in 2013 and 2014. Information regarding stockpile quality can be found in MPMC 2013 and 2014 Annual Environmental and Reclamation Reports (MPMC, 2013, 2014).


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11.5 Acid Rock Drainage/Metal Leaching Characterization Program and Waste Disposal

11.5.1 Waste Rock Characterization and Disposal

Active monitoring of ARD/ML potential in the Mount Polley waste rock continued in 2017 as part of the established protocol which encompasses two stand-alone acid-base accounting (ABA) procedures: ARD analysis of diamond drill core pulps to model a preliminary PAG body; and ongoing ABA determination of individual blast hole samples during mining operations to enhance the segregation of PAG from non-acid generating (NAG) waste. The program characterizes all material types that will be handled during the mine life. Analysis is completed on site by Mount Polley’s LECOTM analytical machine which allows the mine to characterize waste and direct it to suitable storage sites or designate it for construction usage when required and if deemed suitable.

On each bench, a sample of cuttings is collected from each blast hole and analyzed for total copper, non-sulphide copper, iron, and gold. In 2017, blasthole patterns were 7.4m by 8.5m or 7.0m by 8.0m in the Cariboo Pit and the bench height remained at 12 m. Areas of ore and waste are identified by indicator kriging and assigning assay values, mill head value, etc. using an inverse distance calculation. The ore control staff member then establishes ore/waste boundaries based on the calculated mill head values. Millfeed ore areas are excluded from ABA analysis, as this material is processed through the mill. Only waste rock is submitted for ABA analysis. The waste rock material is being sampled at minimum frequency of one sample per 10,000 tonnes of rock in 2017 as an increased QA/QC sample check to minimize the chance of PAG in waste rock piles. Survey data by pit is included in Appendix N of this report.

Samples with both a Neutralizing Potential Ratio (NPR) greater than 2 and a sulphur content less than 0.1% are considered NAG, and samples with both a NPR less than 2 and a sulphur content greater than 0.1% are considered PAG. PAG is currently stored in the Temporary NW PAG Stockpile to the northwest of the Springer Pit, and will be relocated to the bottom of the Springer Pit and submerged upon mine closure.

A summary of quantities of waste rock, tailings, and other mine waste added to site storage areas in 2017, and the total quantities on site as of December 31, 2017 is provided in Table 11.4 and in Table 2 in Appendix N.


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Table 11.4 Quantities of waste rock, tailings, low grade ore, and other mine waste as of December 31, 2017.

11.5.1.1 Springer Pit

No mining occurred in the Springer Pit in 2017. Note that any material from the Springer Pit mining zone refers to the knob atop the wall dividing the Cariboo and Springer Pits.

11.5.1.2 Cariboo Pit

The majority of the Cariboo Pit waste that was blasted in 2017 was NAG. One sample per 10,000 tonnes of rock was collected from the pit and submitted for ABA analysis. No PAG was identified in any grab samples from waste piles in 2017. The Cariboo Pit NAG waste was hauled to either to the SERD, the TSF buttressing project or used for other projects. The PAG was dumped to the west of the Springer Pit in the Temporary NW PAG Stockpile. A summary of what was mined in the Cariboo Pit is provided in Table 11.5 (and in Table 3 in Appendix N). Note that the differences in tonnages between tables reflect error margins on haul truck counts and additional sub-surface rock extraction.

11.5.1.3 Wight Pit/Underground

Underground mining occurred in the Boundary Zone (with the portal located in the Wight Pit) until May 2017 when it was put into care and maintenance. For more details, refer to Section 11.1.1 and Tables 3 and 4 in Appendix N.

2017 Total 2017 Total 2017 Total

Waste Haul Roads 0 0 0 0 201,118 11,244,795South East NAG Dump 0 0 0 0 16,396,284 56,401,765Temporary PAG Stockpile 0 0 4,040,869 24,117,436 0 48,182,524NEZ Dump/Wight Pit Dump 0 0 0 0 0 359,759,809Temporary Rock Stockpile 0 0 0 0 0 25,074Total 0 0 4,040,869 24,117,436 16,597,402 475,613,967

HAC Construction Material 0 0 0 0 25,312 21,906,435TSF Area Construction Material 0 0 0 0 683,001 3,167,590Total 0 0 0 0 708,313 25,079,962

Low Sulphur Waste 0 0 0 0 0 752,433Low Grade Stockpile 0 0 253,716 253,716 923,780 10,414,779Total 0 0 253,716 253,716 923,780 11,167,212Water Treatment Plant - Total 0 0 0 0 3,239 39,511

Low Grade Ore/Coarse Reject/Other Mine Waste

Name of Waste Pile or PondAcid Generating Waste

(tonnes)Potentially Acid Generating Waste

(tonnes)Non-Acid Generating Waste

(tonnes)

Waste Dumps

Tailings Pond


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Table 11.5 Summary of monthly mining production

11.5.1.4 ABA Data

There were 1874 ABA samples analyzed in 2017. Approximately 16% of the waste mined was PAG. These samples were collected to characterize the ML/ARD potential of possible materials milled. ABA samples are collected from blastholes in the pit and from waste stockpiles. No ABA samples were taken from ore stockpiles as the blasthole ABA samples will have already provided a profile of the material. Mill feed and tailings sampling summaries are available in Table 4 in Appendix N. The results of these analyses are summarized here in Table 11.6 and the raw data is tabulated in Appendix N. Note that the differences in tonnages between tables reflect error margins on haul truck counts and additional sub-surface rock extraction.

Table 11.6 Summary of ABA data from the operating pits in 2017.

Pit Samples Tonnes NPR NP C (%) AP S (%) Cariboo - NAG 1,412 15,267,891 9.98 14.66 0.17 2.1 0.06 Cariboo - PAG 248 2,490,261 1.45 15.14 0.18 19.12 0.61

Cariboo SP Ore (NAG) 69 923,780 5.08 14.45 0.17 3.29 0.1 Cariboo SP Ore (PAG) 20 234,088 1.57 5.96 0.07 3.9 0.12

Springer - NAG 100 872,092 11.55 32.65 0.39 4.28 0.13 Springer - PAG 24 209,600 1.73 19.04 0.22 12.39 0.39

Springer SP Ore (PAG) 1 19,627 1.74 23.09 0.28 13.25 0.42 Total 1,874 20,017,340 8.57 15.45 0.18 4.51 0.14

Month PitTotal ore Mined

(tonnes)NAG waste

(tonnes)PAG waste

(tonnes)Overburden

(tonnes)Total waste

(tonnes)

January Cariboo 858,634 903,264 666,150 4,466 1,573,880February Cariboo 720,104 927,371 362,804 0 1,290,175

March Cariboo 511,059 1,242,765 351,707 0 1,594,472April Cariboo 520,339 1,518,745 659,948 0 2,178,693May Cariboo 524,808 1,476,153 564,903 0 2,041,056June Cariboo 470,098 1,518,838 431,216 0 1,950,054July Cariboo 142,935 668,644 186,918 0 855,562

August Cariboo 434,030 1,952,889 274,683 0 2,227,572September Cariboo 377,219 2,080,756 179,698 0 2,260,454

October Cariboo 311,028 1,889,499 97,155 0 1,986,654November Cariboo 175,761 1,838,995 17,767 0 1,856,762December Cariboo 495,694 1,558,154 243,208 28,509 1,829,871

Total 5,541,709 17,576,073 4,036,157 32,975 21,645,205

Mining Summary


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11.5.1.5 Field Grab Samples

In 2017, fifty (50) ABA grab samples were collected from active waste rock dumps for QA/QC purposes during periods when PAG was mined. Note that the site was evacuated for two (2) weeks in July and no PAG was mined during that time. One (1) sample was split and analyzed by the MPMC lab and ALS Laboratory as an annual QA/QC check. One (1) sample was collected from the temporary PAG dump. Fourteen (14) samples taken from NAG dumps resulted in a sulphur content of >0.1% but had an NPR >2, and therefore were constituted as NAG. No ABA grab samples from the NAG or PAG stockpiles had a NPR of <2 and a sulphur content of >0.1%. Results for the LECOTM analysis for these are included in Appendix N.

11.5.1.6 Tailings Storage Facility

Total NAG pit material moved to the dam in 2017 for construction purposes was 683,001 t.

11.5.1.7 Monthly Milling Rates

The total amount of ore sent to the crusher in 2017 was 7,388,595 t. The majority of the feed was extracted from the Cariboo Pit, while the other sources included ore stockpiles and ore mined from the underground pit. A monthly summary of the various ore feeds is provided in Table 11.7. Monthly custom milling production is available in Table 4 in Appendix N.

Table 11.7 Summary of monthly crusher mill rates in 2017

Month Cariboo Pit

Crusher Feed (tonnes)

Stockpiles to Crusher Feed

(tonnes)

Underground to Crusher

Feed (tonnes)

Total Crusher Feed (tonnes)

Cariboo Ore to Stockpiles (tonnes)

January 631,859 22,140 2,322 656,321 234,469February 567,416 43,777 45 611,238 103,712

March 419,812 258,564 7,887 686,263 65,063April 419,256 180,749 9,344 609,349 83,695May 441,957 151,306 4,996 598,259 44,024June 381,631 241,405 0 623,036 31,905July 123,725 142,413 0 266,138 12,154

August 370,830 250,957 0 621,787 19,121September 356,292 431,778 0 788,070 24,290

October 187,767 399,332 0 587,099 124,063November 114,862 518,490 0 633,352 9,642December 475,831 231,852 0 707,683 52,695

Total 4,491,238 2,872,763 24,594 7,388,595 804,833

SourceCrusher Mill Feed Summary


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The total ore milled in 2017 was 6,723,188 tonnes with a daily average target of 21,000 tonnes. A summary is provided in Table 11.8. The 0.09% tonnage discrepancy of total crusher feed from Table 11.7 and total mill feed from Table 11.8 comes from error in the haul truck counts of material delivered to the crusher, as mine operations assumes a constant tonnage for every haul truck coming out of the pit. The mill receives crushed ore from the crusher by conveyor belts, which measure the actual tonnage of material feeding the mill.

Table 11.8 Summary of monthly mill production 2017

11.5.1.8 Tailings

Representative composite tailings samples were collected and analyzed for ABA every month when processing of ore occurred to represent the tonnage of tailings. From January 1 to December 31, 2017, approximately 6,686,158 t of tailings were deposited into the TSF. Table 11.9 displays the ABA data for each of the tailings composite samples for 2017. The composite tailings samples had an average NPR value of 7.894 and range NPR values from 3.75 to 10.99.

Cu (lbs) Au (oz) Ag (oz)

January 495,713 492,805 1,519,755 3,759 2,768February 563,010 559,435 1,862,857 4,888 3,545

March 634,038 629,828 2,078,058 5,164 4,565April 589,768 586,701 1,628,664 4,379 3,600May 596,434 592,223 2,220,122 5,497 3,963June 593,200 589,698 1,757,745 4,082 2,974July 260,759 259,112 857,274 1,837 1,534

August 577,862 574,614 1,659,216 3,844 2,587September 606,005 603,196 1,464,626 4,308 3,203

October 579,690 577,175 1,287,822 3,240 2,690November 645,116 642,654 1,281,191 3,915 2,946December 581,593 578,718 1,453,601 3,097 2,251

Total 6,723,188 6,686,158 19,070,932 48,009 36,626

Tails Tonnage (tonnes)

Metal ProductionMill Production Summary

MonthFeed

Tonnage (tonnes)


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Table 11.9 ABA results from 2017 monthly tailings composite samples

Month Tailings Composite NPR January 3.75 February 10.28 March 7.31 April 7.20 May 8.75 June 7.73 July 10.99 August 6.74 September 8.97 October 7.62 November 9.11 December 6.28 2017 Average 7.894

11.5.1.9 Rock Borrow Pit

No rock was extracted from the rock borrow in 2017.

11.6 Drainage Water Quality Monitoring

An important component in determining and monitoring long-term chemical stability of drainage from the pits and waste rock dumps is water quality monitoring. Locations monitored by MPMC (in addition to sampling required under the Mines Act M-200 and EMA Permit 11678 [refer to the CEMP in Appendix A]), sampling periods, and sampling frequencies are provided in Table 11.10.

These water collection facilities and drainage monitoring locations are shown in Appendix B. MPMC continued the bi-annual seep survey program of all rock waste dumps on site in 2017, with representative seeps being monitored monthly or quarterly when possible (numerous seeps stop flowing during dry periods). Seep monitoring locations are shown in Appendix B. Note that when field parameters of adjacent seeps are consistent, typically only the seep with larger flow is sampled. Results are reported in Appendix E. Collection of this data is used in long-term water quality predictions.


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Table 11.10 Site drainage water quality monitoring locations, and sampling periods and frequencies

Sample Location Drainage Area Sampling Period

Current Sampling Frequency

Cariboo Pit Sump (E8) - 1997 – current Bi-annually1 Wight Pit (E10) - 2006 – current Bi-annually

Pond Zone Pit Sump (E12) - 2010 – 2012 N/A Springer Pit Sump (E11) 2 - 2011 – current Bi-annually1

Boundary Pit - 2012 – current Bi-annually Joe’s Creek Pipe NBD seep 2010 – current Monthly

Long Ditch East RDS, NEZ Dump, SERDS, Wight Pit dewatering 2008 – current Quarterly

SERDS Ditch SERDS, West Ditch, MDC Sump 2012 – current Quarterly

NW Sump (E13) Temporary NW PAG Stockpile, NW Ditch 2012 – current Quarterly

MDC Sump (E14) Upper MDC, West Ditch 2013 – current Quarterly

Bootjack Creek Culvert Sump (E15)

TSF Access Road, Upper Bootjack Creek 2013 – current Quarterly

9km Sump (E17) Temporary NW PAG Stockpile, Junction Zone Ditch 2014 – current Quarterly

TSF Supernatant (E1a) Tailings slurry, seepage collection ponds

1997 – 2014, 2016 – current Monthly3

MESCP (E4) MTD, STD, Main Embankment foundation drains 2001 – current Quarterly

PESCP (E7) Long Ditch, SERDS Ditch, PTD 2001 – 2014 N/A

Central Collection Sump (E18) Long Ditch, SERDS, Ditch, PTD,

MESCP, South Embankment Seepage Collection Pond, TSF (as of 2016)

2014 – current Quarterly

East/West Main Toe Drains (MTDs) TSF Main Embankment toe drains 1998 – current Quarterly

Perimeter Toe Drain (PTD) TSF Perimeter Embankment toe drain 2009 – 2014 N/A

South Toe Drain (STD) TSF South Embankment toe drain 2011 – current Quarterly 1 when pit is not storing water from other sources on site 2 E11 is discussed in Section 5.1.2 3 when barge in TSF is supplying reclaim water to mill; started sampling November 2016; this site is discussed in Section 5.1.2 No obvious trends in the water quality at the drainage location sampling sites have been observed. This is consistent with SRK ore characterization and geochemical source term reports (SRK 2015b; 2016).

11.6.1 Long-Term Predictions – Kinetic Testing

Kinetic rate information is an important component of drainage chemistry prediction that provides a measure of the dynamic performance or “reactivity” of the material being tested. Stephen Day, MSc, PGeo,


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of SRK has been retained to interpret results of the ongoing kinetic-testing program and recommend additional testing, if required. The most updated report was submitted as an appendix of the 2012 Annual Environmental and Reclamation Report. Sample HC13 from the Pond Zone (humidity cell and three column tests) initiated April 20, 2009 is the only test currently running. Additionally SRK completed a report describing the derivation and use of the source terms (SRK, 2016) for the TAR submitted to ENV for the long-term water management application (Golder, 2016c).

11.6.2 Test Heap Leach

In 2006, Mount Polley applied for an amendment to the Mines Act M-200 Permit allowing them to build a Heap Leach Pad and Copper Recovery facility. The amendment was granted on March 29, 2007. The Mines Act M-200 Permit requires that all monitoring data from the facility be included in this report.

In 2014, Mount Polley participated in a research project with Kemetco Research who has been developing a sulphur oxidation bioreactor system for potential use in generating sulphuric acid for copper oxide heap leaching. The heap leach at Mount Polley has been decommissioned until the research is complete. Three batch tests were started at Kemetco Research but the project has been postponed since the TSF embankment breach. Two concentrate samples of the leachate were taken in 2017. The results were 1240 ppm copper and 163 ppm iron in January; and 252 ppm copper and 138 ppm iron in July. In 2017, the total volume retrieved from the leachate collection recycle system (LCRS) was 51.7 m3. Table 11.11 shows the sump levels in 2017.

Table 11.11 Heap leach sump level in 2017

Month Heap Leach Sump Level (ft) January 8.19 February 11.3 March 13.64 April 17.21 May 17.41 June 16.41 July 15.75

August 15.99 September 4.26

October 12.08 November 14.28 December 5.09

11.7 Air Discharge Permit

In 1997, MPMC was issued an Air Discharge permit, (under the former Waste Management Act) by ENV. There are no reporting requirements for this EMA Permit 14590.


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12 Summary and Conclusions

The 2017 monitoring program achieved the objectives, outlined in the 2016 CEMP, (Appendix A) that were submitted to and approved by ENV. To facilitate more effective monitoring and more efficient reporting and reviews in the future, MPMC will continue working with ENV to develop the CEMP. The CEMP is designed to integrate environmental monitoring programs currently being carried out at the mine to meet multiple BC ENV requirements.

Environmental Monitoring in 2017 included:

• Chemistry and quantity of surface, seepage, lake and ground water;

• Rate of deposition of sediment;

• Sediment chemistry;

• Aquatic biology (toxicity testing, fish and benthic community studies, periphyton, fish and benthic tissue chemistry);

• Hydrology of groundwater and surface water flows and levels;

• Meteorology (temperature, precipitation, snowpack, evaporation rates); and

• Wildlife observations.

Monitoring of effluent discharge showed compliance with all parameters and no toxic effects on the environment. The technical memo provided by Tetra Tech (Appendix I) suggests a 3% chance of being able to detect a plume at the IDZ. Effort will continue to try to locate the plume when sampling (only during periods of discharge). Monitoring at the IDZ remains a safety challenge that MPMC is discussing with ENV.

Post-breach monitoring of Quesnel Lake showed no trends or changes from 2016. As of April 7, 2017, the amended EMA Permit 11678 included compliance limits at the edge of the Quesnel Lake IDZ. The maximum results for total copper are similar when the WTP was discharging and not discharging. It is worth noting that there are many inputs into Quesnel Lake, which are contributing to the total copper in the lake, and that the discharge is not the sole contributing factor. No acute BCWQG exceedances were found in any of the receiving environment sites for 2017. Secchi disk readings continue to be similar or better than background readings (prior to 2014).

In the field monitoring program, MPMC exceeded the required QA/QC replicate and blank samples, collecting 13% QC samples.

Mine site surface water and groundwater (not including the Springer Pit Wells) monitoring results were consistent with previous years monitoring.

MPMC aims to collect more hydrology flow measurements in 2018 at the recommendation of the WaterSmith QP.


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The rehabilitation of the Hazeltine Creek corridor will continue as planned (MPMC 2015c) and progressive reclamation of the mine site will continue in 2018.

An increasing trend of wildlife sightings was observed in 2017. Ongoing remediation and reclamation are providing habitat and food for a variety of mammals and birds.

MPMC will continue to work with QPs on recommendations for changes in monitoring plans and implementation of additional monitoring as described in this report and the accompanying appendices.


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13 References

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ENV (BC Ministry of Environment and Climate Change Strategy), (2016). Hazardous Waste Regulations.

ENV (BC Ministry of Environment and Climate Change Strategy), (2017a). British Columbia Approved Water Quality Guidelines: Aquatic Life, Wildlife & Agriculture Summary Report.

ENV (BC Ministry of Environment and Climate Change Strategy), (2017b). British Columbia Working Water Quality Guidelines: Aquatic Life, Wildlife & Agriculture Summary Report.

Environment Canada, (2017). Metal Mining Effluent Regulations. SOR/2002-22.

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Golder Associates Ltd., (2016a). Mount Polley Mine: Review of Monitoring Frequency in Quesnel Lake. Technical Memorandum prepared for and submitted to MPMC, June 27, 2016.

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Knight Piésold Ltd, (2009). Chemical Characterization of the Proposed Effluent for Discharge to Hazeltine Creek. Letter to Mr. Ron Martel, Mount Polley Mining Corporation from Amanda Strouth, Greg


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Smythe and Ken Brouwer. May 11, 2009.

Meays, C, (2012). Derivation of water quality guidelines to protect aquatic life in British Columbia. Science Information Branch, Ministry of Environment, Victoria, BC.

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MPMC, (2015b). Annual Environmental and Reclamation Report. Submitted to Ministry of Environment and Ministry of Energy and Mines, March 31, 2016.

MPMC, (2015c). Rehabilitation Strategy: Summary Table. Updated November 5, 2015.

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MPMC, (2016c). MPMC 2016 Annual Discharge Plan. Submitted to the Ministry of Environment, June 16, 2016.

MPMC, (2016d). Hazeltine Creek Fish Exclusion and Response Plan Rev1. Submitted to Ministry of Environment, May 5, 2016.

MPMC, (2017a). Mine Reclamation and Closure Plan Update January 2017. Submitted to Ministry of Energy and Mines, March 15, 2017.


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MPMC, (2017e). MPMC 2017 Annual Discharge Plan. Submitted to the Ministry of Environment, April 14, 2017.

MPMC, (2017f). Copper Removal Process – Final Assessment Report. Submitted to Ministry of Environment June 8, 2017.

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MPMC, (2017h). Explosive and Nitrogen Management Plan. Submitted to Ministry of Environment January 9, 2018.

Points West Heritage Consulting, (1989). Heritage Resource Overview Assessment, Mount Polley Copper/Gold Project, Williams Lake, BC. Technical assessment submitted to MPMC. Report submitted to Archeology and Outdoor Recreation Branch, October 10, 1989.

R Development Core Team, (2010), R: a language and environment for statistical computing, R Foundation for Statistical Computing, Vienna, Austria.

Seametrics, (2016). INW PT2x Pressure/Temperature Smart Sensor and Data Logger Instructions. Seametrics, Kent Washington, USA.

SonTek, (2007). FlowTracker Handheld ADV Technical Manual. SonTek/YSI Inc, San Diego, California, USA.

SRK, (2015a). Mount Polley Mine Tailings Dam Failure: Update on Geochemical Characterization of Spilled Tailings. Technical Memorandum prepared for and submitted to MPMC, November 2015.

SRK, (2015b). Mount Polley Geochemical Characterization of Ore Stockpiles. Technical Memorandum prepared for and submitted to MPMC, October 2015.

SRK, (2016). Derivation of Geochemical Source Terms, Mount Polley Mine. Technical Memorandum prepared for and submitted to MPMC, September 2016.


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Tetra Tech EBA, (2016). Expected Plume Location by Month. Technical Memorandum prepared for and submitted to MPMC, December 19, 2016.

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