Crown-Indigenous Relations Relations Couronne-Autochtones l ♦I and Northern Affairs Canada et Affaires du Nord Canada Government of Northwest Territories Gouve GIANT MINE REMEDIATION PROJECT Dust Management and Monitoring Plan Version 1.0 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan TABLE OF CONTENTS 1 INTRODUCTION ...... 1-1 1.1 General Setting ...... 1-1 1.2 Giant Mine Remediation Project Team Overview ...... 1-4 1.3 Giant Mine Remediation Project Overview ...... 1-4 1.3.1 Dust Management and Monitoring Plan Overview ...... 1-6 1.3.2 GMRP Environment, Health & Safety, and Community Policy ...... 1-8 1.3.3 Regulatory Framework ...... 1-8 1.3.4 Linkages to other Plans ...... 1-9 1.4 Training and Personnel Safety ...... 1-9 2 AIR QUALITY AND DUST AT GIANT MINE ...... 2-1 2.1 Air Quality Summary ...... 2-1 2.2 Primary Dust Sources ...... 2-1 2.2.1 Tailings Containment Areas ...... 2-2 2.2.2 Roads and Roadworks ...... 2-2 2.2.3 Site Activities as Sources of Dust ...... 2-3 2.3 Factors Contributing to Dust Generation ...... 2-3 2.3.1 Precipitation and Evaporation ...... 2-3 2.3.2 Wind ...... 2-4 2.3.3 Soils and Contamination ...... 2-9 2.3.3.1 Soil Chemistry ...... 2-11 2.3.3.2 Soil Erodibility (Likelihood to Generate Dust) ...... 2-13 3 BEST MANAGEMENT PRACTICES...... 3-1 3.1 Scheduling and Staging ...... 3-2 3.2 Short Term Dust Suppressants...... 3-3 3.3 Physical Coverings ...... 3-4 3.4 Wind Reduction ...... 3-5 PHASE 1 – EXISTING CONDITION ...... 3-6 4 DUST MANAGEMENT AND MITIGATION – PHASE 1 ...... 4-1 4.1 Dust Sources ...... 4-1 4.2 Dust Management Best Practices – Existing Condition...... 4-1 4.2.1 Scheduling and Staging ...... 4-1 4.2.2 Short Term Dust Suppressants ...... 4-2 4.2.3 Physical Coverings ...... 4-2 4.3 Activity-Specific Mitigation Measures – Existing Condition...... 4-2 i January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan 4.3.1 Exposed Tailings ...... 4-2 4.3.2 Roads and Roadworks ...... 4-3 4.3.3 Earthworks ...... 4-3 4.3.3.1 Excavation of Tailings for Paste and Remediation ...... 4-4 4.3.4 Drilling ...... 4-5 5 MONITORING AND RESPONSE FRAMEWORK ...... 5-1 5.1 Wind Monitoring ...... 5-1 5.2 Visual Dust Monitoring ...... 5-3 5.3 Air Quality Monitoring ...... 5-4 5.3.1 Activity-specific monitoring ...... 5-6 5.3.1.1 Response to Activity-Specific OEL Exceedance ...... 5-6 5.3.2 Perimeter Monitoring ...... 5-6 5.3.2.1 Response to Perimeter RBAL Exceedance ...... 5-7 5.3.3 Community Monitoring ...... 5-7 5.3.3.1 Response to Community RBAL Exceedance ...... 5-8 5.4 Contingencies ...... 5-8 PHASE 2 – ACTIVE REMEDIATION AND ADAPTIVE MANAGEMENT ...... 5-10 6 DUST MANAGEMENT AND MITIGATION – PHASE 2 ...... 6-1 6.1 Anticipated Dust Sources ...... 6-1 6.2 Dust Risk Assessment Methodology ...... 6-1 6.2.1 Dust Generating Activities ...... 6-2 6.2.2 Soil Characteristics and Contamination ...... 6-2 6.2.3 Selection of Mitigation Measures ...... 6-3 6.3 Dust Management Best Practices – Phase 2 ...... 6-4 6.3.1 Exposed Tailings ...... 6-4 6.3.2 Roads and Roadworks ...... 6-4 6.3.3 Earthworks ...... 6-5 6.3.3.1 Excavation of Tailings for Paste and Remediation ...... 6-5 6.3.3.2 Quarrying/Borrow ...... 6-6 6.3.4 Infrastructure Demolition and Consolidation ...... 6-6 6.3.5 Drilling ...... 6-7 6.3.6 Blasting ...... 6-7 PHASE 3 – POST-CLOSURE MONITORING AND MAINTENANCE ...... 6-1 7 POST-CLOSURE MONITORING AND MAINTENANCE ...... 7-1 7.1 Sources of Dust...... 7-1 7.2 Monitoring and Contingencies ...... 7-1 8 REPORTING, REVIEW AND LINKAGES - ALL PHASES ...... 8-1 ii January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan 8.1 Reporting ...... 8-1 8.2 Required Review and Updates ...... 8-1 9 REFERENCES ...... 9-1 LIST OF TABLES Table 1.3-1: Regulatory Framework ...... 1-9 Table 2.3-1: Climate Annual Means for Yellowknife, NWT ...... 2-3 Table 2.3-2: Yellowknife Wind Normals: 1981 – 2010 ...... 2-5 Table 2.3-3: Summary of Contaminated Material Characteristics (Adapted from CRP Table 5.4-1 [CIRNAC and GNWT 2019a]) ...... 2-11 Table 2.3-4: Soil Classification Hierarchy ...... 2-13 Table 3.1-1: Best Management Practices – Scheduling and Staging ...... 3-2 Table 3.2-1: Best Management Practices – Short Term Dust Suppressants ...... 3-4 Table 3.3-1: Best Management Practices – Physical Coverings ...... 3-4 Table 3.4-1: Best Management Practices – Wind Reduction ...... 3-5 Table 4.1-1: Activities Requiring Dust Management in Phase 1 ...... 4-1 Table 5.1-1: Wind Thresholds and Action Level Responses ...... 5-2 Table 5.2-1: Dust Events and Action Level Responses ...... 5-3 Table 5.3-1 Site Perimeter Monitoring Locations ...... 5-6 Table 5.3-2 Community Monitoring Station Locations...... 5-7 Table 6.1-1: Activities Requiring Dust Management - Phase 2 ...... 6-1 Table 6.2-1: Risk Rating and Required BMPs ...... 6-3 LIST OF FIGURES Figure 1.1-1: Regional Location of Giant Mine ...... 1-2 Figure 1.1-2: Giant Mine Site Layout ...... 1-3 Figure 1.3-1: Conceptual Diagram of the Three Project Phases ...... 1-5 Figure 1.3-2: Anticipated Dust Levels Through Project Phases ...... 1-6 Figure 2.3-1: Yellowknife Airport Monthly Mean Precipitation, 1943 to 2017 and 2007 to 2017 ...... 2-4 Figure 2.3-2: Wind Rose – Yellowknife Airport (April-May, 2013-2017) (AECOM 2019) ...... 2-6 Figure 2.3-3: Wind Rose – Yellowknife Airport (June-August, 2013-2017) (AECOM 2019) ...... 2-7 Figure 2.3-4: Wind Rose - Yellowknife Airport (September-October, 2013-2017) (AECOM 2019) ...... 2-8 Figure 2.3-5: Wind Rose – Yellowknife Airport (November-March, 2013-2017) (AECOM, 2019) ...... 2-9 Figure 2.3-6: Site Terrain Map ...... 2-10 Figure 2.3-7: Existing Site Conditions – Bedrock / Forest / Wetland Soil Chemistry ...... 2-12 Figure 3.0-1: Hierarchy of Best Management Practices ...... 3-2 Figure 5.3-1: Air Quality Monitoring Stations ...... 5-5 Figure 6.2-1: Activities Ranked by Likelihood of Producing Dust...... 6-2 Figure 8.2-1: Linkages between CRP, Construction-related Plans, and Management and Monitoring Plans ...... 8-3 iii January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan LIST OF APPENDICES Appendix A: Conformity Table Appendix B: MCM Contact Information Appendix C: Giant Mine Remediation Project Environment, Health & Safety, and Community Policy Appendix D: Contingencies Appendix E: Best Management Practices Appendix F: GMRP Air Quality Monitoring Plan iv January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Acronyms and Abbreviations Abbreviation Definition AAQS Ambient Air Quality Standards ACGIH American Conference of Governmental Industrial Hygienists AQMP Air Quality Monitoring Plan BMP Best Management Practices CIRNAC Crown-Indigenous Relations and Northern Affairs Canada (formerly INAC) CRP Closure and Reclamation Plan DCU decontamination unit DMMP Dust Management and Monitoring Plan EHSC Environment, Health & Safety, and Community EQC Effluent Quality Criteria GMRP Giant Mine Remediation Project GNWT Government of the Northwest Territories GNWT-ENR Government of the Northwest Territories – Environment and Natural Resources HEPA high efficiency particulate air JSA job safety analyses LTMP Long-Term Monitoring Plan OEL Occupational Air Exposure Limits OH&S Occupational Health and Safety OMT Ontario Ministry of Transportation MCM Main Construction Manager MVLWB Mackenzie Valley Land and Water Board NT or NWT Northwest Territories PAPR powered air purifying respirators PCMMP Post-Closure Monitoring and Maintenance Plan PF protection factor PM Particulate Matter PPE Personal Protective Equipment PSPC Public Services and Procurement Canada (formerly PWGSC) ppm Parts per million PWGSC Public Works and Government Services Canada RECP Rolled erosion control product RBAL Risk-Based Action Level SDS Safety Data Sheet SOP Standard Operating Procedure TCA Tailings Containment Area(s) TSP Total Suspended Particulates WMMP Waste Management and Monitoring Plan WSCC Workers’ Safety and Compensation Commission WTP Water Treatment Plant °C degrees Celsius cm centimetres μm micrometer km/hr kilometres per hour v January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Abbreviation Definition L litres m meters m2 squared meters (area measurement) mg/kg milligrams per kilogram (equivalent to parts per million) m3 cubic meters (volume measurement) mm millimeters m/s metres per second µg/m3 micrograms per cubic meter vi January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Glossary of Terms Ambient Air Atmospheric air; most often referring to the air outside of buildings and structures. The systematic, long-term assessment of pollutant levels by measuring the quantity and Ambient Air monitoring types of certain pollutants in the surrounding, outdoor air.1 Arsenic Trioxide Dust A poisonous, white amorphous powder with the chemical formula As2O3. The release of particulate matter (typically measured as PM10 and PM2.5) to the Dust Emissions ambient air. Any activity capable of generating dust emissions including, land clearing, earthmoving, tailings excavation, construction, demolition, material handling, storage and/or Dust Generating Activity transporting operations, vehicle use and movement, the operation of any outdoor equipment or unpaved ground surfaces. Dust Suppressant Water or approved chemical stabilizers used as soil treatment to reduce fugitive dust emissions. The process of measuring the amount of pollutants, in a gaseous or particulate form, Emissions Measurement being emitted to the air from a specific source, such as an industrial process.2 Friable Asbestos Asbestos-containing material that can be crumbled to dust when dry, under hand pressure. Fugitive Dust Any particulate matter that becomes airborne as a result of human activity, excluding exhaust stack emissions. Particulate Matter (PM) All airborne solid and liquid particles of microscopic size, with the exception of pure water that remain suspended in the air. PM10 Particulate matter that is less than 10 microns in diameter (< 10 μm). PM2.5 Often referred to as Fine Particulate Matter, this particulate matter is less than 2.5 microns in diameter (< 2.5 μm). Real-Time Air Monitoring Air monitoring conducted at either a portable or permanent station that provides air monitoring data on a continual basis, such as collecting particulate matter concentrations. Total Suspended Particulates Airborne particles or aerosols that are less than 100 micrometers (< 100 μm) are (TSP) collectively referred to as total suspended particulate matter. Visible Emissions Any emissions to air that are visually detectable without the aid of instruments. This does not include condensed uncombined water vapour. 1 US EPA “Ambient Air Monitoring” https://www.epa.gov/air-quality-management-process/ambient-air-monitoring. Updated March 17, 2017. 2 US EPA “Emissions Measurement” https://www.epa.gov/air-quality-management-process/emissions-measurement. Updated March 7, 2017. vii January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Revision History Version Revision No Date Issued Page No Description Reviewed by 1.0 January 2019 Version 1.0 – GMRP viii January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan 1 INTRODUCTION 1.1 General Setting The Giant Mine (Site) is located within the City of Yellowknife boundary, approximately 1.5 kilometres (km) from the community of Ndilǫ and 9 km from the community of Dettah (Figure 1.1-1). The Site is situated on Commissioner’s Land administered by the Government of the Northwest Territories (GNWT). A Reserve (R622T) has been established to allow for the implementation of the remediation of the Site. Subsurface mineral rights are under federal jurisdiction and were withdrawn by Order in Council SI/2005-55 on 15 June 2005. The Site produced gold from 1948 until 1999 and ore for off-Site processing from 2000 until 2004. In 1999, the owner of Giant Mine at the time went into receivership; care, custody, and control of the Site was transferred to Crown-Indigenous Relations and Northern Affairs Canada (CIRNAC) and the GNWT. Ongoing care, maintenance and remediation of the Site is known as the Giant Mine Remediation Project (GMRP). The Site is comprised of eight open pits, extensive mined out underground workings, four tailings containment areas, a water treatment system, and site infrastructure built historically to support mining activities (Figure 1.1-2), some of which continues to be used in support of Care and Maintenance activities, in preparation for site remediation. Dust and air quality monitoring are important components of Site monitoring and management due to the proximity to communities, the large areas of exposed tailings and the planned remediation activities. This document provides the framework for dust mitigation, management and monitoring at Site. (The GMRP Air Quality Monitoring Plan [AECOM 2019] is located in Appendix F of this document and provides greater detail on air quality monitoring at Site.) 1-1 January 2019 PATH: I:\2013\13-1377\13-1377-0115\Mapping\MXD\CRP_25000\1313770115_25000_Fig_1_0_1_RegionalLocation_Rev0.mxd PRINTED ON: 2019-01-22 AT: 8:51:52 AM 640000 KEY MAP Vee Walsh Lake Lake Prosperous Lake INUVIK ! NUNAVUT ! NORMAN WELLS NORTHWEST TERRITORIES Giant Mine YUKON YELLOWKNIFE ! FORT SIMPSON ! HAY RIVER North ! Shot FORT SMITH ! Lake Martin Shot Lake Lake Trapper BRITISH r Lake e COLUMBIA ALBERTA iv R e if n k w o à l Ä l e Y Gar Lake 4 T r a p p e r C re ek B aker Cre Lower ek Martin Lake Pocket Baker Lake Pond k e e r C r e k a B Handle Lake Hay Lake Yellowknife Joe Bay Lake Fox Lake 6930000 Ndilǫ 6930000 Long Lake H! Back Ã Ä Bay 3 Yellowknife Jackfish Lake Airport Niven Lake Frame Lake Yellowknife H! Kam Lake Dettah H! 640000 LEGEND H! COMMUNITY GIANT MINE PROJECT BOUNDARY HIGHWAY REFERENCE(S) COMMUNITY, HYDROLOGY AND TRANSPORTATION DATA OBTAINED FROM GEOGRATIS, © ROAD 0 1,000 2,000 DEPARTMENT OF NATURAL RESOURCES CANADA. MUNICIPAL BOUNDARY CONTAINS PUBLIC WATERCOURSE SECTOR DATASETS MADE AVAILABLE UNDER THE CITY OF YELLOWKNIFE'S OPEN DATA LICENSE V.1. 1:50,000---METRES DATUM: NAD 83 PROJECTION: UTM ZONE 11 MÔWHÌ GOGHA DÈ NÎÎÅÈÈ BOUNDARY -- (SETTLED LANDS OF THE TÅÎCHÔ) PROPONENT PROJECT D IF THIS MEASUREMENT DOESNOT MATCHWHAT IS SHOWN,THE SHEET SIZE HASBEEN MODIFIED FROM: ANSI B YELLOWKNIFE MUNICIPAL BOUNDARY Crown-Indigenous Re lations Relations Couronne-Autochtones l ♦ I and Northern Affairs Canada et Affaires du Nord Canada Giant Mine Remediarion Project ~__!)- 25mm YYYY-MM-DD 2019-01-22 TITLE DESIGNED HM REGIONAL LOCATION OF GIANT MINE PREPARED AA Govem rMMt of REVIEWED HILARY MACHTANS REV. FIGURE Northwest Ten-itories Gouwt~ dn TelTltolres du Nord-Ouesc APPROVED BJORN WEEKS 0 1.1- 1 0 PATH: I:\2013\13-1377\13-1377-0115\Mapping\MXD\CRP_25000\1313770115_25000_Fig_2_0_1_SitePlan_Rev0.mxd PRINTED ON: 2019-01-22 AT: 8:55:38 AM 634000 636000 638000 6936000 6936000 Shot Lake Trapper Lake DAM 22B NON-HAZARDOUS MATERIALS DAM 22A STORAGE AREA HAZARDOUS MATERIALS Gar STORAGE AREA Yellowknife River Lake NORTHWEST POND DAM 21D SOLIDS RETENTION DYKE (SPLITTER DYKE) CONTAINMENT BERM EFFLUENT DAM 21A TREATMENT DAM 21C PLANT (ETP) DAM 21B Tra DAM 3C pp er B4 C DAM 3 re e PIT k SETTLING POND B ake POLISHING r C DAM 1 DAM 3D re 6934000 ek POND DAM 2 6934000 B3 NORTH PIT M&M DAM POND TAILING Pocket REPROCESSING DAM 6 à Lake Ä Baker PLANT 4 Pond DAM 10 (REMOVED) CENTRAL DAM 4 POND DAM 9 STORAGE CALCINE POND DOME MATERIAL B1 STORAGE B2 DAM AREA PIT DAM 8 B2 PIT (UBC) DAM 5 DAM 12 BROCK FORMER SOUTH PIT ROASTER POND AND STACK MILL POND MILL DAM 11 C1 CLAY C SHAFT DAM 7 BORROW DAM C1 PIT Baker Creek FORESHORE TAILINGS AREA 6932000 6932000 A SHAFT Yellowknife Bay Handle Lake A1 PIT TOWNSITE MARINA DWC DAM A2 PIT 634000 636000 638000 LEGEND BUILDING GIANT MINE PROJECT BOUNDARY HIGHWAY INDUSTRIAL WATERCOURSE 0 250 500 REFERENCE(S) INFRASTRUCTURE HYDROLOGY AND TRANSPORTATION DATA OBTAINED FROM GEOGRATIS, © DEPARTMENT OF NATURAL RESOURCES CANADA. ROAD 1:20,000----- METRES DATUM: NAD 83 PROJECTION: UTM ZONE 11 SPLITTER DYKE PROPONENT PROJECT IF IF THIS MEASUREMENT DOESNOT MATCHWHAT IS SHOWN,THE SHEET SIZE HASBEEN MODIFIED FROM: ANSI B SURFACE WATER MANAGEMENT DAM/DYKE Crown-Indigenous Re lations Relations Couronne-Autochtones and Northern Affairs Canada et Affaires du Nord Canada Giant Mine Remediarion Project 25mm TAILINGS OR SLUDGE RETENTION DAM l ♦ I ~__!)- WATERCOURSE YYYY-MM-DD 2019-01-22 TITLE INDUSTRIAL WATERBODY DESIGNED DP GIANT MINE SITE LAYOUT D PIT BOUNDARY PREPARED AA WATERBODY Govem rMMt of REVIEWED HILARY MACHTANS REV. FIGURE - Northwest Ten-itories Gouwt~ dn TelTltolres du Nord-Ouesc APPROVED BJORN WEEKS 0 1.1-2 0 Giant Mine Re1nediation Project Dust Management and Monitoring Plan 1.2 Giant Mine Remediation Project Team Overview The GMRP is jointly managed through a Cooperation Agreement, with the Government of Canada and the GNWT. The GMRP Team consists of CIRNAC and the Government of the Northwest Territories – Environment and Natural Resources (GNWT-ENR) acting as co-proponents with respect to the Environmental Assessment and other regulatory considerations. Public Services and Procurement Canada (PSPC) provides contracting services, contract management, and technical support services to CIRNAC. PSPC has awarded the Main Construction Manager (MCM) contract to Parsons Incorporated. This contract will be used to complete implementation activities for the GMRP. The MCM is responsible for overall site management including emerging risks on site and supporting planning efforts for closure and reclamation during the GMRP. The MCM is responsible for letting and managing various sub-contracts, with the goal of providing employment and maximizing training opportunities for Indigenous peoples and Northerners. Once remediation begins, the MCM will oversee the implementation of the Closure and Reclamation Plan (CRP) and associated activities. The GMRP Team is working towards permanent closure and reclamation of the Giant Mine Site. While CIRNAC will ultimately be responsible for compliance with the Type A Water Licence and Land Use Permit issued for the GMRP, the proposed dust management methods are conducted by private sector contractors procured through the MCM, who is managed by PSPC. The MCM will be responsible for ensuring required dust management controls are in place and working properly. Procured contractors will be required to adhere to dust mitigation and monitoring details once Design and Construction Plans are approved. Refer to Appendix B for an updated list of contact information for MCM staff responsible for dust management for the GMRP. 1.3 Giant Mine Remediation Project Overview The GMRP is defined by three reclamation-focused phases (see Figure 1.3-1): • Phase 1: Existing Condition - Project Definition; from licence issuance until the first remediation activity commences • Phase 2: Active Remediation and Adaptive Management - implementation of the approved closure activities, which has three corresponding sub-phases, applied on a component-by-component basis: • Detailed Design • Active Remediation/Construction (implementation of specific closure activity) • Adaptive Management (confirmation of component performance) • Phase 3: Post-closure Monitoring and Maintenance1 – long-term monitoring and maintenance after all site remediation is complete 1 Post-closure maintenance of this site includes ongoing operation of the Water Treatment Plant and the active cell in the non-hazardous landfill where treatment residuals will be disposed and managed. 1-4 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Figure 1.3-1: Conceptual Diagram of the Three Project Phases Phase 1 Phase 2 Phase 3 (ornp oni:!11t Detailed Adaptive Active Remediation #1 Mana ement Mine Cu111punl•nl Existing Active Remediation Adaptive Management Post-Closure declared /1'2 Desi n orphaned Condition Monitoring and (Project Comp,o_ nentl Detailed Desien ~...... Active Remediation Adaptive ond 11 Maintenance abandoned lkfi11iliu•1} :======:::;=~--...!:======:::==M===a=n=a~=em===e=n::::::t Component Adaptive Detailed Design Active Remediation #4 Mana ement Core and Long-term site monitoring Moint,mance and management Phase 1 is defined as the period that commences when a Water Licence is issued for site remediation, prior to commencement of remediation activities; however, this period really extends back to 1999, when the mine’s owner went into bankruptcy and CIRNAC assumed responsibility for the Site. Phases 2 is the core phase of the GMRP and commences once the first remediation activity is implemented. This phase includes three sub-phases: detailed design, implementation, and performance assessment of the closure plan activities described in the CRP and approved by the Mackenzie Valley Land and Water Board (MVLWB). Phase 2 applies to the GMRP as a whole, but its sub-phases are divided and applied to each component of the CRP individually (CRP Sections 5.1 to 5.10 [CIRNAC AND GNWT, 2019a]). This approach enables one component to be undergoing detailed design, another active remediation, while a third has yet to commence, as it may require completion of another activity to be implemented. All closure activities enter a period of adaptive management once completed. Phase 3 is the point at which the remediation of all components of the CRP are complete and adaptive management indicates they are performing as anticipated. At this point, the definition of the GMRP essentially changes from a remediation project to a post-closure monitoring and maintenance project. The purpose moving forward through Phase 3 will be to monitor the Site to ensure it meets closure criteria and continues to reflect the site objectives for the 100-year term of the project; this includes continued operation of the water treatment plant (WTP) to confirm discharged minewater meets effluent quality criteria (EQC). It is anticipated a new Water Licence application will be submitted as the project enters post-closure, as has been done for other remediation projects in the Mackenzie Valley. Details on the project phases in relation to development, implementation and monitoring is provided in Section 5.0 of the GMRP CRP (CIRNAC and GNWT 2019a). Site-wide dust management and mitigation procedures are anticipated to be similar in all three phases, though activities will change as remediation progresses. Levels of dust are expected to increase in Phase 2 during the peak of remediation activities, and slowly taper off as activities conclude. The end state air quality at the Site is expected to be similar to background levels (Figure 1.3-2). Refer to Section 8.2 for information on required review and updates of applicable procedures. 1-5 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Figure 1.3-2: Anticipated Dust Levels Through Project Phases ~ PHASE 1 PHASE 2 PHASE 3 ~ EXISTING CONDITION ACTIVE REMEDIATION ADAPTIVE MANAGEMENT MONITORING Traffic/road dust Traffic/ road dust Backfilline of Pits & UG Paste Backfi II Freeze Proeram General waste handline Demoliti on and Debris Removal Borrow and Quarry Contaminated soils Soil Remedi ati on Exposed Tailines Coveri ne of TCAs Baker Creek Realienment ti Anticipated Dust Level Ant1c,pated peak Anticipate air quality comparable ::, 0 (darker=more dust) dust production --> to surrounding region 1.3.1 Dust Management and Monitoring Plan Overview The objective of the dust management plan is to ensure that dust is mitigated, managed, and monitored to ensure dust impacts to human health, safety and the environment from the Site are minimized during each phase of the project. This will be achieved through proactive implementation of best management practices to control dust, and through active monitoring of wind and dust conditions. This plan is intended as a guide for decision making with respect to dust management and monitoring throughout the project. This plan provides the tools necessary to manage the existing condition at site, and to develop robust activity-specific mitigation and monitoring plans as required by the licence for Phase 2. This plan is split into three sections to reflect the three phases of the project. Phase 1 is provided in detail. Phase 2 reflects the level of information available to the Project at commencement of licencing, prior to detailed designs being completed for some of the key components of the CRP. Updated versions will be submitted with updated information as remediation progresses. A detailed discussion of how advancement of final design and site remediation links to plan updates is provided in Section 8. A clean-copy of this Plan will be submitted within 90 days of Licence issuance to reflect any updates or changes resulting from commitments and direction provided during the Licence process. In addition, updated versions will be submitted with new information as remediation activities progresses, as per standard Board processes. Phase 1 – Existing Condition Phase 1 of the Project is the existing condition of the Site, from the day of Water Licence issuance until active remediation begins. As detailed further in Section 4, the primary dust sources pre-remediation include the tailings containment areas, roads and road use, and earthworks related to site stabilization activities. Outlined in this plan: • Areas of concern at Site; 1-6 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan • Best management practices; • Methods for assessment of dust likelihood and risk; • Mitigation measures implemented to address current dust issues at site; • High-level monitoring commitments; and • Reporting timelines and requirement. This plan will be updated regularly to reflect changes in best management practices and risk assessment, as well as other operational and regulatory updates, as necessary. Phase 2 – Active Remediation and Adaptive Management In Phase 2, each project component or activity will be required to submit detailed design construction and monitoring plans for approval prior to implementation. These plans will include: • Details of the dust assessment for each component; • The selected best management practices for dust suppression and preventative controls that will be installed, maintained, and removed during implementation; • Monitoring and maintenance information specific to work being completed; and • Schedules and timelines for implementation. Closure activities of note are detailed in Section 6.1 (Anticipated Dust Sources). Although some dust generation is anticipated while carrying out these closure activities, once implementation of closure activities is complete, dust levels at the Site are expected to return to comparable air quality to the surrounding region. Existing sources of contaminated mineral materials that may have resulted in dust (i.e., tailings) will have then been covered and, therefore, eliminated as a potential source of fugitive dust. Adaptive management for dust and air quality will be structured to confirm the implemented closure activities (e.g., covers or borrow source areas) are not susceptible to wind erosion. Phase 3 – Post-Closure Monitoring and Maintenance Phase 3 of the GMRP is defined as the long-term monitoring of the site. Dust monitoring will continue to determine whether dust from roads and laydown areas used to support long-term monitoring and maintenance at the Site requires mitigation. Should Phase 3 air quality monitoring demonstrate air quality at the Site to be similar to background levels, and dust monitoring confirms no significant dust sources remain at the Site, the air quality monitoring program may be scaled back or discontinued after consultation with affected parties. 1-7 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan 1.3.2 GMRP Environment, Health & Safety, and Community Policy Within GMRP, the health and safety of employees and protection of the environment are an over-riding priority. Management is committed to doing everything possible to prevent injuries and to maintain a healthy environment. To this end the GMRP is committed to: • Protecting the environment and the health and safety of its employees; contractors and the general public; • Engaging meaningfully with stakeholders; • Delivering local social and economic benefits; and • Being a recognized leader in EHSC management among public environmental remediation projects. To this end, GMRP will act in a manner that minimizes its negative impacts, maximizes its positive benefits, and continually seek ways to improve its performance. Overall Commitments In order to achieve these objectives, the GMRP is committed to the following: • The GMRP will plan and execute in a manner that respects and cares for people and the environment. • The GMRP will comply with all applicable environmental, health and safety, and community (socio-economic and engagement) regulatory, policy and other requirements. • The GMRP will apply best management practices including best available technology and processes for environmental protection and public safety. • The GMRP will promote a project-wide culture committed to continual improvement in environmental, health and safety, and community guided by the EHCS Management System. Senior managers are responsible for ensuring that all the requirements of the Environment, Health & Safety (EHS) Policy are fully implemented. See Appendix C for the full GMRP Environment, Health & Safety, and Community Policy. 1.3.3 Regulatory Framework All work carried out at the Site is being implemented within a framework of federal and territorial legislation, policies and guidelines (See Table 1.3-1). Those used in the creation of the Dust Management and Monitoring Plan (DMMP) include: 1-8 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Table 1.3-1: Regulatory Framework Federal Territorial Contaminated Sites Environment, Health and Safety Policy Guideline for the General Management of Hazardous Waste (AANDC 2006) in the NWT (GNWT 1998) Canada’s Occupational Health & Safety Regulations Guideline for Dust Suppression (GNWT 2013) SOR/86-304 (2014) Best Practices for the Reduction of Air Emissions from Guideline for Ambient Air Quality Standards in the Northwest Construction and Demolition Activities (ECCC 2005) Territories (GNWT 2014) Guidance Document on Air Zone Management (CCME WSCC Codes of Practice for Asbestos Abatement (WSCC 2012a) 2012) Achievement Determination Canadian Ambient Air Quality Standards for Fine Particulate Matter and Ozone (CCME Asbestos Safety Act and Regulations. (WSCC 1997) 2012b) Guideline for the Management of Waste Asbestos. (GNWT Other 2004) General Guidelines for Asbestos Removal and Disposal. Ontario’s Ambient Air Quality Criteria (OMOE 2012) (GNWT 2010) 1.3.4 Linkages to other Plans The Dust Management and Monitoring Plan is a requirement of the licence and is intended to guide actions at site and future activity-specific construction/design plans. The DMMP informs and is informed by: • Closure and Reclamation Plan (CRP) (CIRNAC and GNWT 2019a); • Erosion and Sediment Management and Monitoring Plan (CIRNAC and GNWT 2019b); • Tailings Management and Monitoring Plan (CIRNAC and GNWT 2019c) • Waste Management and Monitoring Plan (CIRNAC and GNWT 2019d) • GMRP Air Quality Monitoring Plan (AQMP) (AECOM 2019) 1.4 Training and Personnel Safety Personnel will receive an orientation related to non-hazardous wastes sorting, handling of hazardous materials and WHMIS training as part of the general safety training for employees and contractors. All workers onsite are expected to have WHIMIS training and TDG certificates (among other training) before personnel commence work on site. Specific training is provided for personnel working directly with hazardous waste handling, and the handling of arsenic and asbestos-contaminated materials. Monthly checklist type audits will be conducted to verify training by the MCM. When working with any arsenic-contaminated wastes, personnel are required to use Personal Protective Equipment (PPE) and safety procedures must be adhered to at all times: • When working with arsenic, personnel are required chemical resistant coveralls with hood (Tychem QC®) with additional outer rain suits for select tasks, plus chemical resistant boots and inner and outer gloves with barrier cream, and a full-face shield. • PPE will be effectively worn by project staff and is rated by the manufacturer to provide protection from arsenic, asbestos, and the other hazardous materials on site. 1-9 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan • Use of powered air purifying respirators (PAPRs) with high efficiency particulate air (HEPA) filters. All employees who use this equipment will receive respirator training and will be quantitatively fit tested and verified for adequate flow prior to entering the work area applies a protection factor (PF) of 1,000 to the PAPR. • Supplied air respiratory protection is available for select tasks with a greater potential for exposure to arsenic or asbestos. For example, during removal of crocidolite asbestos, if there is a potential for exposure to gaseous substances (hydrogen cyanide or arsine) or if airborne arsenic levels exceed 5 milligrams per cubic metre (mg/m3). It should be noted, however, that the supplied air respiratory protection provides the same protection factor from particulate matter as a PAPR when quantitatively fit tested. Use of supplied air will be covered in the subcontractor job safety analyses (JSAs) and approved by the MCM health and safety coordinator • Airstream respirators are required if dusty conditions are present. • Avoid skin contact with arsenic sludge, dust or powder. • Avoid inhalation of arsenic sludge, dust or powder. • Avoid arsenic sludge, dust or powder from contacting clothing. • Prevent arsenic sludge, dust or powder from contacting the eyes. • Wash thoroughly after handling arsenic sludge or dust. • Comprehensive decontamination techniques will be undertaken in clearly defined work zones and showering after each departure from the exclusion zone using specialty designed decontamination unit (DCU) trailers complete with three air locked decontamination stages and ventilated using HEPA filtered negative air units. • An employee’s personal clothes will not be worn in the hazardous work areas and will remain in clean rooms that are maintain and verified clean through air and surface wipe sampling. • Shower after the completion of your work. • Do not eat or smoke until after completing wash up. Properly decontaminate work clothing or dispose of it in containers suitable for containing arsenic. • Low, moderate, and high-risk work on site have been identified by the MCM and applicable PPE requirements identified for each. New task that have not yet been categorized will undergo hazard identification and risk analysis to determine PPE requirements in accordance with the applicable regulations. • Baseline arsenic urinalysis testing. 1-10 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan 2 AIR QUALITY AND DUST AT GIANT MINE 2.1 Air Quality Summary Existing air quality in the area surrounding the Giant Mine site is a product of activities at the site including wind erosion of site features and facilities, emissions from sources in the Yellowknife area (e.g., dust from traffic and wind erosion), and intermittent flows from regional sources, such as forest fires when they occur. Ambient air quality has been monitored intermittently at Site (INAC and GNWT 2010) for many years beginning in 2005, but a formal program, the Air Quality Monitoring Plan (AQMP), began in 2013. The AQMP (AECOM 2013; AECOM 2018) consists of a community air quality monitoring component and a site perimeter monitoring component. Site perimeter monitoring also includes provision for mobile temporary stations that are used to monitor activity-specific dust levels. In general, the objectives of the AQMP are to maintain compliance with established GMRP air quality criteria during remediation activities, and to minimize and assess the impacts to community air quality as a result of remediation activities. Activity-specific air quality monitoring is also completed as part of maintaining worker health and safety on site as well as to monitor for fugitive dust that may affect nearby land and water. It is used as an early warning in order to signal a dust issue and mitigate the risk prior to an exceedance at a site perimeter or community air monitoring station. Activity-specific air quality monitoring results may be used to validate the ambient air quality results, as required, but they are not incorporated into the general ambient air quality assessment. In general, the AQMP results from 2013-2017 show that during Care and Maintenance, the ambient air quality at the Giant Mine Site was similar to local conditions with some exceptions. Site perimeter stations have measured only three incidents since 2014 that exceeded the acceptable criteria which were not due to smoke from regional forest fires, fog, snow, or sleet. The community stations have also recorded measurements above air quality criteria, however, there have been no exceedances for arsenic level criteria (SLR 2015, 2017, 2018). The majority of particulate concentrations measured above the established standards at the community stations were found to be likely caused by smoke from regional forest fires during summer months and from dust from adjacent roads, measured during the spring before and during the times winter road sand was removed. On none of these occasions was the wind direction such that the sampling locations were consistently downward of the Site. Wind directions on these days placed the sampling locations either upwind or crosswind of the Site, or were variable throughout the sampling day (SLR 2015, 2017, 2018). See the AQMP (AECOM 2019) and Section 5.0 for more details on monitoring. 2.2 Primary Dust Sources The two main causes of dust at the Site are: wind erosion of site features and facilities (landforms, engineered structures, waste areas, etc.), and wind dispersion of materials released during on-site activities (disturbance). 2-1 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan With respect to wind erosion, the following factors determine the extent to which dust will be created: • Size of the exposed area • Soil structure/type/humidity • Wind speed Similar factors are at play in the creation of dust when materials are disturbed as a result of site activities: • Characteristics of the material being disturbed, including particle size and humidity, and • Wind conditions at the time of the activity. The tailings containment areas and the road network are the largest facilities vulnerable to wind erosion. 2.2.1 Tailings Containment Areas Tailings at the Giant Mine site are a by-product of historic mining operations where a slurry of saturated fine particles were deposited into the various tailings ponds. Tailings are the largest potential source of fugitive dust at the Site at the commencement of remediation activities. The surface of the tailings ponds begin to dry out during the spring and summer and become a significant potential source of dust without proper management. There are four tailings ponds that comprise the Tailings Containment Areas (TCAs) at Site (South Pond, Central Pond, North Pond and Northwest Pond) which are actively managed to ensure dust does not reach unacceptable levels.). The Closure and Reclamation Plan identifies that three of the four tailings areas will be covered, and topped with a cover of large coarse rock that is not susceptible to wind erosion. The fourth (South Pond) will be excavated. Therefore dust mitigation of exposed tailings is a medium-term consideration which will be eliminated once covers are in place. Monitoring will occur to ensure the covered tailings areas are effective in achieving closure objectives. 2.2.2 Roads and Roadworks There is a road network that spans approximately 30 kilometers on the Giant Mine Site, including the chip sealed old Highway 4 and the re-aligned Highway 4/Ingraham Trail which cut through Site. In addition to general wind erosion, road use activities further increase the potential for dust generation, including: • General traffic movement. • Movement of heavy equipment. • Grading and contouring of existing roads. • The construction of berms and new roads, if needed. Due to the materials used in their construction, parking areas, storage areas, and turnaround areas can also generate dust. Several kilometers of this road network will eventually be graded and re-contoured for remediation. Air quality monitoring will occur during this work. 2-2 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan 2.2.3 Site Activities as Sources of Dust The proposed Closure and Reclamation activities are intended to stabilize the site by isolating or removing sources that currently contribute contaminant loads to surface waters and sediment through erosion and/or leaching. However, carrying out the remediation activities themselves will result in disturbance of soils and sediments. Potential sources of dust warranting the most attention are: 1. Large areas being exposed for extended periods. 2. Activities conducted in areas of high arsenic and other contaminants; and/or 3. Activities which occur in the near vicinity of natural water bodies. Site activities specific to the project phase will be further detailed in Sections 4 (Phase 1 - Existing Condition) and 6 (Phase 2 – Active Remediation and Adaptive Management). 2.3 Factors Contributing to Dust Generation 2.3.1 Precipitation and Evaporation The climate of the North Slave region is characterized by cool summers, very cold winters, and low humidity; it is considered one of the drier regions of Canada (INAC and GNWT 2010). Climate data from the Yellowknife airport meteorological station are available and climate means for the 1943 to 2017 and 2007 to 2017 time periods for Yellowknife, Northwest Territories (NWT) are summarized in Table 2.3-1. The 2007 to 2017 means are used to summarize recent conditions (within the last ten years), for comparison with the 1942 to 2017 long- term mean. July is the hottest month with a maximum mean temperature of 21 degrees Celsius (°C) and January the coldest month with a minimum mean of -31.1°C. (ECCC 2017). Table 2.3-1: Climate Annual Means for Yellowknife, NWT Climate Variable Long-Term Mean (1943–2017) Recent Mean (2007–2017) Air temperature (°C) -4.8 -3.7 Total snowfall (cm) 140.5 155.2 Total rainfall (mm) 157.7 173.8 Total precipitation (mm) 270.5 283.0 Source: ECCC 2017. °C = degrees Celsius; cm = centimetre; mm = millimetre. Yellowknife’s long-term (1943 to 2017) mean annual snowfall is 140.5 centimetres (cm), and mean annual rainfall is 157.7 millimetres (mm). A snowfall peak can be observed in January and November for the long-term (1943-2017) and short-term (2007-2017) averages (Figure 2.3-1), while rainfall has historically peaked in August but in more recent years has shifted to a September peak (Kokelj et al. 2012). 2-3 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Figure 2.3-1: Yellowknife Airport Monthly Mean Precipitation, 1943 to 2017 and 2007 to 2017 Dataset - 2007-2017 data - 1943-2017 data Rainfall (mm) 50 +------< 40 30 20 10 0 1------'~------=----~---_.L.--_ _.L.__ _ _.L______.______,___ _ ~ --~~---1 Snowfall (cm) Total Precipitation (mm) 50 40 30 20 10 0 Jan Feb Mar May Jun Jul Aug Sep Oct Nov Dec Month Date source: ECCC 2017 mm = millimetre; cm = centimetre 2.3.2 Wind Wind contributes to the dispersion, re-suspension and surface drying through evaporation; all of which have the potential to release dust particles. As such, wind conditions are very important in understanding the potential distribution of airborne contaminants throughout the Site. Wind conditions are monitored on an on-going basis by the Air Quality Monitoring contractor using both the on-site meteorological stations and reports from ECCC and are reported to the MCM to inform site activities and required mitigations. (See Section 5 for monitoring and response framework related to wind levels.) The average wind speed recorded at the Yellowknife airport between 1981 and 2010 was 12.8 kilometres per hour (km/hr) (ECCC 2017). Average wind speed ranges from 10.7 km/hr (January) to 14.3 km/hr (October). In June, July, and August, the most frequent winds were from the south (Table 2.3-2), while winds from the east dominated the rest of the year (Table 2.3-2). 2-4 January 2019 Giant Mine Remediation Project Dust Management and Monitoring Plan Table 2.3-2: Yellowknife Wind Normals: 1981 – 2010 Frozen Conditions No Snow/Unfrozen Ground Frozen Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Speed (km/h) 10.7 11.6 12.7 13.7 14.1 13.4 12.6 12.9 13.7 14.3 13.3 11.2 Most Frequent Direction E E E E E S S S E E E E Maximum Hourly Speed 72 61 61 64 64 68 64 64 72 64 64 57 (km/h) ever recorded Direction of Maximum NW NW NW NW NE NW N N W NW NW NW Hourly Speed Maximum Gust Speed 105 98 74 93 87 89 85 80 105 93 113 80 (km/h) Direction of Maximum Gust W N NW SW NW W N N W NW W SE Days with Winds >= 52 0.2 0.2 0.2 0.1 0.1 0.1 0.1 0.0 0.5 0.4 0.0 0.1 km/h Days with Winds >= 63 0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1 0.0 0.0 km/h Source: ECCC 2017 The mean wind speed during the seven-month snow-free period (shown in grey above) is 13.5 km/h. The maximum hourly wind speed average was recorded at 72 km/h in September 1957 and the maximum gust wind speed ever reached was 113 km/h in November 1956. Extreme wind events are rare compared to many other Canadian cities, with only an average of 1.8 days/year where winds reach speeds over 53 km/hr, and an average of only 0.3 days/yr where wind speeds have exceeded 63 km/h. Wind roses are a convenient and efficient method to present wind data, illustrating measured total wind speed, wind direction and wind class frequency for local wind patterns. Wind data from the Yellowknife Airport was compiled for the period from 2013 to 2017 as part of updating the AQMP (AECOM 2019) and is shown graphically as seasonal Wind Roses (Figures 2.3-2, 2.3-3, 2.3-4 and 2.3-5). Note that the wide part of the rose’s petals denotes where the wind is blowing from, and the tip of the triangle points where the wind blew. The coloured portions show the relative frequencies of various wind speeds. During non-snow covered months (typically April to October), the most frequent wind strength is between 2.10 to 3.60 metres per second (m/s), with the prevailing wind originating from the south, with good distribution of winds from the north as well. 2-5 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Figure 2.3-2: Wind Rose – Yellowknife Airport (April-May, 2013-2017) (AECOM 2019) 10% 8% WEST EAST WIND SPEED (nv's) D ,..11.10 • 8.80-1110 • 5.70-8.&l • 3.60-5.70 D 210- 3.so D o.so.2.10 Celms;0,57% SOU1H 2-6 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Figure 2.3-3: Wind Rose – Yellowknife Airport (June-August, 2013-2017) (AECOM 2019) NORTH 10% 8% WEST EAST WIND SPEED (mis) D ,-11.10 - 6.80-11.10 - 5.70-8Jll - 3-60-5-70 D 2-10-3_1;0 D o-50 - 2-10 calms: 0.83% SOUTH 2-7 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Figure 2.3-4: Wind Rose - Yellowknife Airport (September-October, 2013-2017) (AECOM 2019) NORTH 10% 8% WEST EAST WIND SPEED (mis ) D >:11.10 • 8.80-11.10 • 5.70-8.80 • 3.60-5.70 D 2.,0-3.so D o.so. 2.10 Calms: 0.72".4 SOUTH 2-8 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Figure 2.3-5: Wind Rose – Yellowknife Airport (November-March, 2013-2017) (AECOM, 2019) NORTH 10% WEST EAST WIND SPEED (mis) D - 11.10 - 8.80-11.10 - 5-70-8.80 - 3.60-5.70 D 210.3_50 D oso-2.10 Clllms: 284% SOUTH 2.3.3 Soils and Contamination As described in the CRP (CIRNAC and GNWT 2019a), the Site lies within a zone of discontinuous permafrost. The native soil consists of till and gravel deposits, overlain by glaciolacustrine clays and silts. Areas with peaty organic soils can be up to 1 m thick in some areas. The most prevalent soils in the area are glacial till (Figure 2.3-6). 2-9 January 2019 PATH: I:\2013\13-1377\13-1377-0115\Mapping\MXD\CRP_25000\1313770115_25000_Fig_2_2_2_Terrain_Rev0.mxd PRINTED ON: 2019-01-22 AT: 8:59:38 AM 634000 636000 638000 6936000 6936000 Shot Lake Trapper Lake à 4 Ä Gar Yellowknife River Lake T r a p p e r C re ek 6934000 6934000 Pocket Lake Baker Pond B a k e r C r e e k 6932000 6932000 Yellowknife Bay Handle Lake 634000 636000 638000 LEGEND HIGHWAY FOREST TERRAIN GIANT MINE ACCESS MORAINAL (BLANKET) ROAD MORAINAL (THIN NOTE(S) ROAD VENEER) TERRAIN CLASSIFICATION MAPPING GENERATED FROM LIDAR ANALYSIS. REFERENCE(S) PROJECT BOUNDARY MORAINAL (VENEER) 0 500 1,000 HYDROLOGY AND TRANSPORTATION DATA OBTAINED FROM GEOGRATIS, © DEPARTMENT OF WATERCOURSE WETLAND TERRAIN NATURAL RESOURCES CANADA. 1:20,000--- METRES DATUM: NAD 83 PROJECTION: UTM ZONE 11 COLLUVIUM PIT BOUNDARY --- - PROPONENT PROJECT TAILINGS IF THIS MEASUREMENT DOESNOT MATCHWHAT IS SHOWN,THE SHEET SIZE HASBEEN MODIFIED FROM: ANSI B TERRAIN POLYGON Crown-Indigenous Relations Relations Couronne-Autochtones D BOUNDARY FLUVIAL (APPROXIMATE) - l ♦ I and Northern Affairs Canada et Affaires du Nord Canada Giant Mine Remediarion Project ~__!)- 25mm LACUSTRINE DOMINANT SURFICIAL YYYY-MM-DD 2019-01-22 TITLE MATERIAL ORGANIC - SITE TERRAIN MAP BEDROCK - DESIGNED SF D DEVELOPED - PREPARED AA WATERBODY GovemrMMt of REVIEWED HILARY MACHTANS REV. FIGURE - Northw est Ten-itories Gouwt~ dn TelTltolres du Nord-Ouesc APPROVED BJORN WEEKS 0 2.3-6 0 Giant Mine Re1nediation Project Dust Management and Monitoring Plan 2.3.3.1 Soil Chemistry Existing soil chemistry and arsenic loading conditions are well documented in the CRP (Section 5.4 of CRP [CIRNAC and GNWT 2019a]). Figure 2.3-7 illustrates the arsenic concentrations in the soil surrounding the project components. Table 2.3-3 describes the soil characteristics and level of contamination of the primary contaminated materials that will be the focus of earthworks and excavation. Table 2.3-3: Summary of Contaminated Material Characteristics (Adapted from CRP Table 5.4-1 [CIRNAC and GNWT 2019a]) Material Types Description This heterogeneous material is typically dominated by sand (0.425 to 2 mm) and gravel (4.75 to 19 mm) with angular cobbles (75 to 300 mm) and boulders (>300 mm) and minor to some silt and clay. Contaminated Contaminant sources include arsenic-rich roaster stack emissions and/or mineralized waste rock. These granular fill sources have resulted in total arsenic concentrations >340 mg/kg (>160 mg/kg within the Townsite/Marina). This material is located within the Developed Areas (refer to Section 5.4.4.1 of the CRP). Heavily This material is a subset of the contaminated granular fill and is located in the mill/roaster area. This contaminated material represents contaminated granular fill with total arsenic concentrations greater than granular fill 4,500 mg/kg, the maximum total arsenic concentration of tailings. This material is composed of silt and clay with minor to some sand and is identified as glacial till / lacustrine native soil. This material is located within the Developed Areas (below the contaminated granular fill) and the bedrock/forest/wetland terrain (refer to Section 5.4.4.2 of the CRP). Within the Contaminated bedrock/forest/wetland terrain, this material is typically overlain by peaty organic soil of variable fine-grained soil thickness. Contaminant sources for this material are associated with arsenic leaching from overlying contaminated granular fill within the Developed Areas and arsenic-rich roaster stack emissions within the bedrock/forest/wetland terrain. Total arsenic concentrations are >340 mg/kg (>160 mg/kg within the Townsite/Marina). This material is a subset of the contaminated fine-grained soil and contaminated granular fill located PHC- within the Developed Areas (refer to Section 5.4.4.1 of the CRP); however, the primary contaminant contaminated soil source is PHCs. Concentrations of PHC parameters are greater than the applicable guidelines. The tailings are typically classified as a sandy silt to a silt with some sand: particle size ranges from a medium-grained sand (particle diameter of 2 mm or less) to clay-sized (particle diameter of 0.002 mm or less). In addition to the materials in the TCAs, tailings are located west of the Polishing and Settling Tailings and ponds towards Baker Pond (i.e., Area 4), within historical Jo-Jo Lake, and within the Mill Pond. Calcine calcine was historically deposited within the former Calcine Pond located adjacent to B1 Pit. Typical arsenic concentrations in the tailings are approximately 2,000 to 4,000 mg/kg, with a few samples in the 5,000 mg/kg range. The tailings are also enriched in antimony, cadmium, lead, and sulphur relative to natural crustal abundances. This material is composed of a mix of coarse sand and silt which grades towards a finer sand and silt Contaminated with depth. Contaminated sediment is located within Baker Creek and along the shoreline of Yellowknife sediment Bay (i.e., nearshore sediment). Contaminant sources for this material are described in Section 5.4.3.4 of the CRP. The erodibility (potential to create dust) of the various soil types is discussed further in Table 2.3-4. 2-11 January 2019 PATH: I:\2013\13-1377\13-1377-0115\Mapping\MXD\CRP_25000\1313770115_25000_Fig_5_4_2_ExistingSiteConditions_SoilChemistry_Rev0.mxd PRINTED ON: 2019-01-23 AT: 10:47:54 AM 636000 638000 Yellowknife River 6936000 6936000 Shot Lake Trapper Lake Gar Yellowknife River Lake NORTHWEST POND à 4 Ä B4 T rap PIT pe r C re e k SETTLING B3 POND B PIT ake POLISHING r C re 6934000 ek POND 6934000 JO-JO NORTH LAKE POND Pocket Lake Baker Pond CENTRAL POND B1 PIT B2 PIT (UBC) SOUTH DE POND T AIL BROCK MA P: CO PIT RE I CORE ND B1 PIT US INDUSTRIALAREA T R I AL A R E A (S C A L E B2 PIT 1 :1 C1 0 (UBC) ,0 0 PIT 0 0 ) Baker Creek Baker Creek SOUTH POND 6932000 6932000 Yellowknife Bay A1 PIT A2 PIT 636000 638000 LEGEND BAKER CREEK BEDROCKCREVASSE ARSENIC 0 250 500 BREAKWATER CONCENT RATION NOT E(S) (mg/kg) ARCGIS SOFTWARE USED KRIGING INTERPOLATION METHOD TO INTERPRET DISCRETE SOIL GIANT MINE PROJECT CHEMISTRY DATA POINTS. KRIGING METHOD ASSUMES THE DISTANCE AND DIRECTION BOUNDARY 0 - 340 1:20,000---METRES BETWEEN SAMPLES REPRESENTS A SPATIAL CORRELATION THAT CAN BE USED TO EXPLAIN -- VARIATION IN THE SURFACE. GIS TERRAIN MODEL COMBINED WITH INTERPOLATED SOIL REFERENCE(S) GIANT MINE ACCESS 340 - 3000 ROAD CHEMISTRY DATA TO CREATE HEAT MAPS, BY TERRAIN TYPE. KRIGING INTERPOLATION IS HYDROLOGY AND TRANSPORTATION DATA OBTAINED FROM GEOGRATIS, © DEPARTMENT OF 3000 - 4500 LIMITED TO THE EXTENT OF SAMPLE POINTS. AS A RESULT, THE INTERPRETATION DOES NOT NATURAL RESOURCES CANADA. HIGHWAY COVER THE FULL EXTENT OF THE PROJECT AREA. DATUM: NAD 83 PROJECTION: UTM ZONE 11 4500 + WATERCOURSE PROPONENT PROJECT FOREST/WETLAND IF THIS MEASUREMENT DOESNOT MATCHWHAT IS SHOWN,THE SHEET SIZE HASBEEN MODIFIED FROM: ANSI B BAKER POND ARSENIC Crown-Indigenous Re lations Relations Couronne-Autochtones DOWNGRADIENT OF CONCENT RATION l ♦ I and Northern Affairs Canada et Affaires du Nord Canada Giant Mine Remediarion Project ~__!)- 25mm DAM 3 (mg/kg) YYYY-MM-DD 2019-01-23 TITLE PIT BOUNDARY D 0 - 340 DESIGNED SF EXISTINGSITECONDITIONS –BEDROCK/FOREST/WETLAND SHORELINE LANDS D 340 - 3000 AND SOILCHEMISTRY ~ 3000 - 4500 PREPARED AA NEARSHORE D 4500 + Govem rMMt of REVIEWED HILARY MACHTANS REV. FIGURE TCA POND Northwest Ten-itories Gouwt~ dn TelTltolres du Nord-Ouesc APPROVED BJORN WEEKS 0 - - 2.3-7 0 Giant Mine Re1nediation Project Dust Management and Monitoring Plan 2.3.3.2 Soil Erodibility (Likelihood to Generate Dust) Soil characteristics determine the soil’s potential for wind erosion and dust creation. Silty soils have the highest erodibility classification while well-graded gravel has the lowest erosion potential. Table 2.3-4: Soil Classification Hierarchy Erodibility Classification Soil Type Soil Erodibility Rating Most Silt Silty Loam High Loam Silty Sand Sandy Loam Silty Clay Loam Medium Sandy Clay Loam Silty Clay Sandy Clay Clay Heavy Clay Loamy Sand Low Sand Poorly Graded Gravel Least Well-Graded Gravel When considered in conjunction with the contamination of soils at site, the need for active management of dust throughout this project is clear. 2-13 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan 3 BEST MANAGEMENT PRACTICES Fugitive dust management strategies are developed by addressing the two main causes of dust emissions - wind/drying, and physical disturbance - through: Managing wind erosion on site by: • changing the properties of the surface of the erodible material; • reducing the speed of the wind as it flows over a surface; or • minimizing the surface area exposed to wind erosion; and Minimizing and mitigating surface disturbance through: • sound engineering practices and timing of activities, • implementation of applicable and targeted dust mitigation measures to daily and overall activities, and • where possible, avoidance of key areas. Mitigation measures (Best Management Practices) presented in this plan can be grouped into the following categories: 1. Scheduling and staging of activities – includes considerations of season, access, and responding to environmental conditions 2. Short-term dust suppressants – both proactive and reactive use 3. Physical covers – short-term physical covers may be used during remediation, and permanent physical covers will be a significant part of closure activities 4. Wind control – may be employed in fixed locations where practical and necessary. Figure 3.0-1 illustrates the ascending level of effort as a result of the increase in likelihood or risk of dust. 3-1 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Figure 3.0-1: Hierarchy of Best Management Practices 4. Wind Control 3. Physical Covers 2. Short-term Dust Suppressants 1. Scheduling and Staging of Activities As depicted above, all site activities must be scheduled and staged with dust management in mind. Short term suppressants will be used for most activities. Physical covers and wind control will be considered on an as- needed basis. Remediation goals and stakeholder and affected party input will also be considered in selection of dust mitigation measures to ensure community input is addressed in managing and monitoring for dust and its potential impacts. An elaboration and analysis of the Best Management Practices (BMP’s) described below is provided in Appendix E. BMP’s are adapted from Ontario Ministry of Transportation (OMOT) (2015). 3.1 Scheduling and Staging Scheduling and staging BMP’s (Table 3.1-1) are essential factors to be considered early in all activities and design planning. These will guide decisions regarding timing and sequence of operations and highlight important factors to consider. These measures may include limiting unnecessary traffic or disturbance, or protocols for stoppage of work during high wind events. Table 3.1-1: Best Management Practices – Scheduling and Staging Scheduling and Staging of Activities Name Earthworks Tailings Containment Areas Activities Drilling Demolition Activities Blasting Roads Considerations Design and It is essential to properly design and implement a site-specific dust management Implement plan to ensure that sediment is not released from the site. This includes monitoring, ESC and maintenance and decommissioning. DMP Plan 3-2 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Table 3.1-1: Best Management Practices – Scheduling and Staging Scheduling and Staging of Activities Name Earthworks Tailings Containment Areas Activities Drilling Demolition Activities Blasting Roads Considerations The sequence of construction should be specified with consideration of site Optimize management and scheduling BMPs. The construction sequence should be Construction compatible with plans for progressive reclamation, instream works, stockpile Sequence operation, etc. Erosion and dust potential can be minimized by installing BMPs as soon as Install BMPs practical and always before soil is exposed. Early installation may require site Early access or traffic control considerations. Areas that are sensitive to disturbance and areas that must not be disturbed should Sensitive Area be clearly signed to convey that message. This also includes areas that represent a Signage safety hazard, such as highly contaminated areas. The site should be accessible from a limited number of points. Frequently- used Site Access access roads should be paved or graveled to minimize the tracking of material off Management site. Enforcing reduced vehicle speeds on unpaved roads. Vehicle washing on stabilized worksite entrances will minimize off-site sediment tracking. Maximize Dust potential is reduced by working during relatively wet conditions. This includes Favorable consideration of the season of construction and may require a larger number of Weather resources to complete the project in a shorter time. By minimizing the total disturbed soil area and the disturbed soil area at any time, Minimize the wind erosion potential is reduced and the quantity of sediment control Exposed Soils measures is reduced. Stripping of new areas should be delayed as long as possible and restoration of constructed areas should be done as soon as possible. Stockpiles should not be located near watercourses, exposed areas, or environmentally sensitive areas. Stockpiles should be protected against erosion by Stockpile water and wind immediately after they are established. This can be done by Management applying water or suppressant, and protecting from the wind using wind breaks or synthetic cover. Erosion and dust potential can be minimized by restoring or reclaiming constructed Restore Early areas as soon as possible by applying cover. 3.2 Short Term Dust Suppressants Short Term Dust Suppressants (Table 3.2-1) will apply to nearly all activities. As the simplest form of mitigation, dust suppression can be achieved through use of approved chemicals or water. Timing, type, and frequency of application will be determined by factors such season, winds, and the whether the material is arsenic-bearing. 3-3 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Table 3.2-1: Best Management Practices – Short Term Dust Suppressants Short Term Dust Suppressants arthworks Name E Tailings Containment Areas Activities Drilling Demolition Activities Blasting Roads Considerations Inexpensive. Application of water increases soil cohesion. Rate of water application Wet must be at least equal to the rate of evaporation and infiltration. Note that care must suppression be taken to prevent mud tracking if this is done. Approved chemical treatments can be applied to increase soil cohesion. It may be Chemical applied in conjunction with hydro-treatments. Chemical treatments may be Stabilization expensive and must be designed for site- specific conditions. Note that care must be taken to prevent mud tracking if this is done. Inexpensive. Freezing of pore water in soils or tailings reduces likelihood of wind Snow and Ice erosion. Heated water to produce ice cover. Additional snow can be used and Cover compacted to prevent drifting. Increases wetting in spring. 3.3 Physical Coverings Physical coverings (Table 3.3-1) will be considered where activities must be carried out in areas of arsenic- containing soils or during the transport of contaminated materials. Physical coverings may also be considered when winds are high or other factors dictate an increased level of control. This may include simple measures like the use of tarps to secure loads or stockpiles. In the larger scale, the object of many of the remediation activities will be to apply a permanent physical cover (e.g. – tailings ponds). Table 3.3-1: Best Management Practices – Physical Coverings Physical Coverings Name Earthworks Tailings Containment Areas Activities Drilling Demolition Activities Blasting Roads Considerations Plastic Plastic sheeting or tarps can be used to secure loads, or on slopes to prevent Sheeting dust. It is relatively easy and inexpensive to install. Rolled Erosion Control Products (RECP) provide a high degree of uniform and Rolled long-lasting erosion protection. Care should be taken to ensure that the product Erosion is suitable for the intended application and that it is applied in accord with the Control manufacturer’s specifications. Permeable RECP’s are used in conjunction with Products vegetation. Impermeable RECP’s may be used for protection of stockpiles. Highly effective long term solution; impractical in short term. Gravel and rock Aggregate blankets can stabilize soil surfaces and can be used in combination with other Cover types of cover. Little to no maintenance. Aggregate and rock covers should be designed by a qualified engineer. Impractical in the short-medium term. Effective at erosion and dust management Revegetation in the long term. Not applicable to the active reclamation stage, however natural revegetation will be promoted for some components of closure. 3-4 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan 3.4 Wind Reduction Wind reduction (Table 3.4-1) mitigations may be required where higher dust generating activities must be carried out, and where suppression activities are not sufficient. They may also be used where there are values at risk down-wind (water bodies etc.). Table 3.4-1: Best Management Practices – Wind Reduction Wind Reduction Name Earthworks Tailings Containment Areas Activities Drilling Demolition Activities Blasting Roads Considerations A wide variety of non-erodible elements have been used at mine sites, including tires, straw bales, and rocks. This method can provide >90% control but is highly Non-Erodible dependent on the size of the non-erodible elements and density of placement over Roughness the erodible surface. Random vs. linear placement perpendicular to prevailing Elements winds. The particular element used is typically dependent upon cost and local availability. Minimize dust from disturbed soils and surfaces by reducing wind speeds downwind Wind Breaks of fences. Large engineered structure vs. mesh pre-fab product. Typically installed and Screens in space limited areas (e.g. property lines) where other options are not feasible and where winds tend to be unidirectional. Relatively low cost. For high dust-generating activities, high risk areas, or where other mitigations prove insufficient: • Placement of non-erodible elements to reduce wind speed. • Use of wind fences. • Use of wind screens (both up-wind and down) around quarries to block wind and reduce dust spread from blasting and crushing, particularly where activities are conducted near Baker Creek. 3-5 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan PHASE 1 – EXISTING CONDITION (Project Definition; from licence issuance until the first remediation activity commences) January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan 4 DUST MANAGEMENT AND MITIGATION – PHASE 1 4.1 Dust Sources As described in Section 2, site facilities (tailings areas and roads) have significant potential for dust generation and require active management until closure (see Table 4.1-1 below). Table 4.1-1: Activities Requiring Dust Management in Phase 1 Activities Requiring Dust Management Roadworks • grading and contouring of existing roads • use and maintenance of existing roads to support remediation and monitoring activities Earthworks • excavation and movement of tailings for paste production and remediation • windblown erosion of exposed in-situ or stockpiled soils and tailings • development of temporary access roads/pads Drilling • geotechnical or geophysical drilling, • boreholes for equipment placement • boreholes for concrete delivery underground 4.2 Dust Management Best Practices – Existing Condition The following sections describe the general best management practices that are currently employed. 4.2.1 Scheduling and Staging Current practices in this category: • Controlling vehicle/equipment speeds. • Restricting traffic to designated roads/corridors, as needed. • Road and surface disturbances are minimized through proper road maintenance. • Driver training. • Limiting disturbance of tailings. • Tailings are left as wet as possible to prevent wind erosion. • Grading or covering piles to minimize wind exposure. • Using machinery appropriate for the job. For high-wind events (see Section 5.1 for details on wind categories): • Operating within acceptable wind speeds: reduce or suspend disturbance/activities in high winds. For elevated-arsenic areas: • Consulting map of elevated arsenic areas. • Washing of vehicles prior to leaving contaminated areas. 4-1 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan • Paste production is done in a covered area. 4.2.2 Short Term Dust Suppressants Current practices in this category: • Tailings are frozen in place/snow covered through the winter months. • Use of approved soil stabilizer or water as appropriate. • Water or suppressant can be re-added as needed. For high-wind events (see Section 5.1 for details on wind categories): • Increase vigilance. • Reapply as needed and as possible. For high dust-generating activities: • Use of irrigation whenever possible during deconstruction, drilling, blasting, quarrying and all earthworks. For elevated-arsenic areas: • Increase vigilance. • Consider approved chemical stabilizer where water is insufficient. 4.2.3 Physical Coverings Current practices in this category: • Paste production is carried out in a shelter. • Covering of tailings during transport. For high-wind events: • Cover piles or disturbed soils during high wind events. 4.3 Activity-Specific Mitigation Measures – Existing Condition Standard Operating Procedures include the following mitigation measures, which have been successful in managing dust at Site. 4.3.1 Exposed Tailings Management practices at this stage of the project focus on scheduling and staging, and short-term dust suppressants: • An approved soil stabilizer is added in the spring and as needed throughout the year. 4-2 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan • Tailings are not disturbed once the coating has been applied or coating is reapplied if disturbed. • Tailings are kept as wet as possible to prevent wind erosion. • Water or suppressant can be re-added as needed. • Tailings are frozen in place/snow covered through the winter months. • Tailings work will be suspended pending evaluation of site conditions and activities when a Level 2 wind or dust level is reached. (See Section 5.1 and 5.2 for details on wind and dust levels.) Temporary physical covers (e.g. tarps), and wind control measures may be considered, if the current mitigation is insufficient. Significant physical covers will not be employed until closure. 4.3.2 Roads and Roadworks Prevention of dust from roads is accomplished through the use of short-term dust suppressants and procedural mitigation measures (staging): • Application of an approved dust suppressant in spring and summer and as needed. • Roads are watered between applications of approved dust suppressant. • Road and surface disturbances are minimized through proper road maintenance. • Road maintenance (grading and repair) is curtailed during high wind conditions (See Section 5.1). • Controlling vehicle/equipment speeds to 25 km/h or less on all roads, with the exception of specific sections where speeds up to 40 km/hr are permitted. • Controlling vehicle/equipment speeds to 15 km/h around buildings and work sites. • Restricting traffic to designated roads/corridors, as needed. • Reducing disturbance when Level 3 wind or dust level is reached except to monitor and stabilize roads (See Sections 5.1 and 5.2 for wind and dust levels). • Driver training. • Washing of vehicles prior to leaving contaminated areas. A Traffic Management Plan will be developed for the Site as a result of the Giant Mine Environmental Agreement, 2015. Wind control measures may be considered if recurring issues arise. 4.3.3 Earthworks Standard practices to minimize dust during earthworks activities focus on scheduling and staging, and short-term dust suppression: • Consultation of a site arsenic contamination map prior to earth moving. • Minimize unnecessary disturbance. 4-3 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan • Soil or tailings are wetted down prior to, during, and after to prevent wind erosion. • Excavated piles of soil or tailings are graded and contoured to be kept low (20° to 40°) or covered with other material to prevent drying. • Soil excavation may be suspended in high wind environments (Level 2 or 3) and exposed piles are watered to prevent wind erosion. • Machinery used for soil or tailings disruption is to be appropriately sized for the level of effort, to minimize soil disruption as much as possible. • Respect relevant road dust mitigation measures while carrying out earthworks. Additional dust control best practices that may be applied during one or more of the earthworks activities planned for remediation may include wind control measures and temporary physical covers: • Use of tarps or tackifier when transporting loads. • Using engineering controls such physical coverings. • Placement of non-erodible elements to reduce wind speed. • Use of wind fences. • Use of snow and ice. • Application of straw mulch or crop residue to limit erosion during a specific activity. 4.3.3.1 Excavation of Tailings for Paste and Remediation The use of tailings for paste production has been a large part of the Site Stabilization Work at site; paste is used to stabilize the underground mine stopes, chambers and bulkheads. In addition to the Earthworks mitigation measures outlined above, these mitigations will be implemented when working with tailings: • Tarps or a soil tackifier are used when transporting tailings and placing tailings on stockpiles. • A tent is set up near the Tailings Reprocessing Plant for paste production for protection from wind and to reduce tracking to other parts of the mine site. • Tailings excavation will be suspended in high wind environments (Level 2 or above) pending evaluation of site conditions and mitigation measures by the MCM, and exposed piles are watered to prevent wind erosion. Additional dust control measures may be applied as outlined in earthworks activities. 4-4 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan 4.3.4 Drilling Short-term dust suppression will be the predominant mitigation during drilling: • Wet drilling involves the use of water combined with air to flush drill cuttings, preventing dust generation through the capture of dust particles in drilling water. • Drill water will be collected and managed according to the Waste Management and Monitoring Plan (WMMP) (CIRNAC and GNWT 2019d). • Dry drilling involves the use of a dust collector during drilling. • Should a dry drilling method be implemented due to the timing of the year, cuttings will be wetted to ensure they do not become airborne. Timing of the activity will be dependent upon the timing of the year and wind speeds, and additional measures may be added if concerns arise as to the anticipated contaminant levels in the dust. 4-5 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan 5 MONITORING AND RESPONSE FRAMEWORK Monitoring is fundamental to the Dust Management and Monitoring Plan. The dust monitoring program is developed to be predictive, proactive, and reactive to the presence of dust on site, through wind monitoring (Section 5.1), dust event monitoring (Section 5.2), and air quality measurements undertaken through the AQMP (AECOM 2019). Wind forecasts and wind monitoring provide a daily and real-time operational framework. Visual monitoring alerts operators to react quickly to reduce dust levels and prevent any potential dust impacts to surrounding communities. Air quality monitoring both at or near the Project boundary and in the communities of Yellowknife and Ndilo measures the effectiveness of the dust management practices and provides a feedback loop to determine effectiveness of the Plan. The Response Framework outlined here provides thresholds and mitigations for wind-, dust-, and concentration- based action levels. When any threshold is exceeded, whether it is wind speed, visual dust, or air quality concentration, the pre-defined action levels require implementation of a response to prevent or reduce airborne dust. This response framework: • Provides a graduated approach to response through appropriate action levels. • Reduces the likelihood of escalation of dust events and the potential for particulate matter to reach the community. • Reduces the likelihood of shut-down of remediation activities. • Provides timely notification to construction managers should Risk-Based Actions Levels (RBALs) for PM10 and/or TSP be triggered. • Continuously monitors the concentrations of target parameters at the community monitoring stations to evaluate long-term air quality. This long-term data record allows GMRP personnel and regulators to determine the efficacy of the RBAL limits and mitigation measures. 5.1 Wind Monitoring Wind forecasts are consulted each morning and throughout the day by the Air Quality Monitoring contractor and reported to the MCM. Wind warnings are e-mailed and communicated on-site to all relevant staff and contractors. Long-term meteorological monitoring data is archived as a data analysis tool for interpretation of the perimeter and community air quality data. Wind Thresholds, based on the Beaufort wind force scale (visual cues)1, are established to guide day-to-day operations and responses. Note that these action levels are based on wind speeds alone and not on visible dust events. The wind speed threshold (the speed at which wind erosion will occur) is typically in the range of 5.0 m/s (18 km/hr) for most mine tailings materials (SENES 2012). Wind that is laden with soil particles becomes more 1 The Beaufort wind force scale ‘is an empirical measure that relates wind speed to observed conditions at sea or on land.’ (Royal Meteorological Society 2018) 5-1 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan abrasive and therefore increases the impact that wind friction can have on exposed soils and tailings (OMOT 2015). In support of this, the Level 1 Wind Threshold triggers increased vigilance and suppression as the wind forecast approaches the speed at which tailings and road dust are likely to begin. While occurrences have been infrequent, analysis of air quality and wind speed monitoring data from 2013-2017 confirms that activities are more likely to cause dust events when operating at wind speeds greater than 30 km/hr (AECOM 2019). As such, Level 2 Wind Threshold (as outlined in Table 5.1-1 below) indicates that earthworks in contaminated soils and tailings requires greater awareness, planning and execution. Depending on the nature, location and duration of the work, activities may be suspended if wind thresholds approach Level 2. Other high-dust generating activities may be suspended if mitigations (suppression, covers, etc.) are not successful. It is anticipated that dust-generating work would stop for Level 3 or higher wind events to prevent a dust event from occurring. Efforts would be focused on suppression and other mitigation measures as appropriate. To be noted: the action levels detailed in the AQMP (AECOM 2019) should a site perimeter or community air monitoring station experience one or more real-time exceedances trump the responses below. Table 5.1-1: Wind Thresholds and Action Level Responses Wind Thresholds Response Level 1 Level 1 Moderate Winds. Sustained or gusting winds • Vigilance: Increase frequency of Security patrols in all active between 15 km/h and less than 30 km/h. work areas and in high risk areas such as TCAs. • Dust suppression: increase water or dust suppressant as appropriate. • Employ basic BMP's. Physical Cues: Raises dust and loose paper. • Continue with work as scheduled. Small branches are moved. Light flags • Should monitoring identify increased visual or quantitative dust extended. levels, apply mitigations. Level 2 Level 2 Moderate to high winds with gusting. • Vigilance: Increase frequency of Security patrols in all active Sustained winds between 30 km/h and less work areas and in high risk areas such as TCAs. Watch for dust than 40 km/h. Gusting up to 45 km/hr. moving off-site. Notify staff and contractors of wind warning. • Dust suppression: increase water or dust suppressant as appropriate. • Should monitoring identify increased visual or quantitative dust levels, apply mitigations. • Reduce disturbance where possible. Reduce wind erosion using temporary physical covers or wind blocks. Physical Cues: Small trees with leaves begin • High-dust activities (quarrying, other earthworks) may be to sway. Crested wavelets form on inland suspended if mitigation measures not successful. waters. • Do not resume high risk or high dust activities until wind dies down to within Level 1 threshold range. 5-2 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Table 5.1-1: Wind Thresholds and Action Level Responses Wind Thresholds Response Level 3 Level 3 • Vigilance: Increase frequency of Security patrols in all active High Winds. Sustained winds over 40 km/hr work areas and in high risk areas such as TCAs. Watch for dust or gusting over 45 km/hr. moving off-site. Notify staff and contractors of wind warning. • Dust suppression: increase water or dust suppressant as appropriate. • Reduce wind erosion using temporary physical covers or wind blocks. Physical Cues: Large branches in motion. • Suspend high-risk and high-dust activities (quarrying, Whistling heard in telephone wires. Umbrellas earthworks). used with difficulty. • Do not resume high risk or high dust activities until wind dies down to within Level 1 threshold range. 5.2 Visual Dust Monitoring Visual monitoring of dust is carried out during daylight hours, 365 days of the year through routine patrols. On- site personnel watch the work sites for any visible dust that may develop and Security Officers watch for dust as part of their routine patrolling of the property. This dust may be present outside active work areas or at low levels that do not trigger the perimeter air quality monitoring equipment alarms. The action levels below (See Table 5.2-1) assist with ensuring that dust is mitigated and air quality concentrations do not exceed the environmental and occupational concentrations identified. They are an indication that standard mitigations are not enough. Appropriate mitigations are to be implemented immediately. After implementation, these actions will be monitored to ensure they have addressed and abated the source of dust. To be noted: the action levels detailed in the AQMP (AECOM 2019) should a site perimeter or community air monitoring station experience one or more real-time exceedances trump the responses below. Table 5.2-1: Dust Events and Action Level Responses DUST EVENTS Response Apply water or approved tackifier. Site component (gravel, soil, tailings, drilling Long-term stabilization is preferred unless further movement is waste, etc.) is dry and is producing dust as a imminent. Level 1 Level result of wind. Consider temporary cover if practical. Workers wear appropriate PPE. Investigate source of dust. Have water applied to affected area as soon as practicably possible, if safe to do so (it won’t flush sediment into nearby waterbody). Visible airborne dust is emitting from areas of active or recent activity. Reduce disturbance if practical. Level 2 Level Workers wear appropriate PPE. Monitor sensors, and watch for dust moving off-site. Update SOPs with successful strategies. 5-3 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Table 5.2-1: Dust Events and Action Level Responses DUST EVENTS Response Continue to apply water or suppressants. Workers wear appropriate PPE. Airborne dust continues despite increased Monitor sensors, and watch for dust moving off-site. application of suppressants. Review design plan for activity; if selected dust mitigation options Level 3 Level are not working, discuss with Site Supervisor for an improved solution. Consider temporary wind blocks or physical covers. Update SOPs with successful strategies. MCM to contact PSPC representative and CIRNAC. Suspend work in the vicinity immediately and initiate emergency watering or appropriate mitigation as necessary to control dust. Airborne dust continues despite additional Review design plan for activity; if selected dust mitigation options mitigation measures. are not working, discuss with Site Supervisor for an improved Level 4 Level solution. Reconsider scheduling & staging options and other measures that are possible. Continue to apply water or suppressants. 5.3 Air Quality Monitoring In preparation for the demolition of the Roaster Complex, CIRNAC commissioned a study of existing ambient air quality criteria for arsenic and other airborne contaminants, and to identify appropriate air quality criteria (Arcadis 2013) for monitoring. The resulting framework was required to demonstrate that it was protective of human health in surrounding communities during future remediation activities. Building on this work and the successful implementation of the AQMP since 2013, ambient air quality monitoring will continue during remediation to ensure compliance with the DMMP and to assess whether the applied dust control measures are sufficient. Air quality monitoring is structured in three tiers: activity-specific monitoring (as and when needed), site perimeter monitoring, and community monitoring. (See Figure 5.3-1 for the locations of site perimeter and community air quality monitoring stations.) Thresholds are set for environmental alarms based on occupational air exposure limits, and relevant ambient air quality standards. Air quality concentrations for Occupational Air Exposure Limits (OEL’s) are based on occupational health and safety standards for personnel using appropriate personal protective equipment and are based on the American Conference of Governmental Industrial Hygienists (ACGIH) standards, as prescribed by the Canada Occupational Health and Safety Regulations. Community thresholds are based on relevant 24-hour Ambient Air Quality Standards (AAQS); where there are no NWT guidelines, Canada-Wide Standards or Ontario Ministry of Environment standards are used. Monitoring intensity is determined by levels established within the AQMP; see the AQMP (AECOM 2019) in Appendix F for full details. Results of monitoring will provide immediate feedback as to the efficacy of dust management practices at site. 5-4 January 2019 PATH: I:\2013\13-1377\13-1377-0115\Mapping\MXD\CRP_25000\1313770115_25000_Fig_2_1_6_CRP_AQ_MonitoringStations_Rev0.mxd PRINTED ON: 2019-01-22 AT: 8:57:01 AM 634000 636000 638000 640000 Yellowknife River 6936000 6936000 Shot Trapper Lake Lake C-NORTHWEST !( Gar Lake NORTHWEST Yellowknife River !( POND H-NORTHWEST POND B-4 Tr ap PIT pe r C SETTLING r e e k POND Ba ker POLISHING Cre A-NORTH ek !( 6934000 POND 6934000 B3 POND PIT NORTH Lower POND à Martin Pocket Ä Lake Lake 4 Baker Pond CENTRAL G-WEST !( POND B1 B2 PIT PIT (UBC) SOUTH POND k e e r !( BROCK C I-SOUTH r e PIT k POND a B D-BEACH !( C-1 PIT E-A1C1 !( 6932000 6932000 Yellowknife Handle Bay Lake A1 B-/TOWN PIT !( A2 YKB PIT !( F-MARINA Fox Lake NDL !( 6930000 6930000 Ndilǫ H! à 3 Ä Jackfish Lake NIVEN !( 6928000 6928000 Yellowknife H! NATIONAL AIR POLLUTION !( SURVEILLANCE (NAPS) 634000 636000 638000 640000 LEGEND H! COMMUNITY AIR QUALITY MONITORING STATIONS !( COMMUNITY MONITORING STATION GNWT MONITORING STATION !( 0 500 1,000 REFERENCE(S) !( SITE PERIMETER STATION HYDROLOGY AND TRANSPORTATION DATA OBTAINED FROM GEOGRATIS, © DEPARTMENT OF NATURAL RESOURCES CANADA. BREAKWATER - -- 1:30,000---METRES DATUM: NAD 83 PROJECTION: UTM ZONE 11 GIANT MINE PROJECT BOUNDARY PROPONENT PROJECT IF IF THIS MEASUREMENT DOESNOT MATCHWHAT IS SHOWN,THE SHEET SIZE HASBEEN MODIFIED FROM: ANSI B HIGHWAY Crown-Indigenous Re lations Relations Couronne-Autochtones and Northern Affairs Canada et Affaires du Nord Canada Giant Mine Remediarion Project 25mm ROAD l ♦ I ~__!)- WATERCOURSE YYYY-MM-DD 2019-01-22 TITLE D PIT BOUNDARY DESIGNED JC AIR QUALITY MONITORING STATIONS, GIANT MINE REMEDIATION PROJECT PREPARED AA Govem rMMt of REVIEWED HILARY MACHTANS REV. FIGURE Northwest Ten-itories Gouwt~ dn TelTltolres du Nord-Ouesc APPROVED BJORN WEEKS 0 5.3-1 0 Giant Mine Re1nediation Project Dust Management and Monitoring Plan 5.3.1 Activity-specific monitoring Activity-specific monitoring is conducted for higher risk activities which have the potential to create significant dust and/or are in areas such as tailings contaminated areas. These monitors are placed around the specific activities in upwind and downwind locations to ensure air quality in the immediate vicinity of the activity remains within acceptable occupational health and safety levels, and to identify issues before triggering the perimeter monitors. Worker health and safety monitoring is conducted in accordance with plans developed in cooperation with the Worker Safety and Compensation Commission (WSCC) and the contractor. Health and Safety Standards and Regulations applicable to air quality and dust monitoring are also identified in Section 1.3.3 above. These standards regulate the acceptable size of particulate matter and the quantity of airborne dust that may be generated during an industrial undertaking; and identify required and best practices for handling of wastes that easily become airborne or erode. In addition, health and safety standards defining allowable concentrations of substances within the dust produced at the Giant Mine site have been considered and incorporated as applicable. 5.3.1.1 Response to Activity-Specific OEL Exceedance Activity-level OEL exceedances result in immediate investigation, notification of findings, and potentially stoppage of work based on the investigation findings. When safe to do so, suppression and additional mitigations will be implemented, following the procedures outlined for a Dust Event (Table 5.2-1). Throughout the project, the perimeter and community monitoring stations will also continue to be monitored. Addressing dust at the source of any activity-level monitoring exceedance should result in site perimeter dust 3 3 concentrations less than PM10 of 159 µg/m or TSP of 333 µg/m depending on the proximity of the activity- specific monitors to the site perimeter monitors. 5.3.2 Perimeter Monitoring The nine (9) perimeter stations provide real-time monitoring of TSP and PM10: Table 5.3-1 Site Perimeter Monitoring Locations Station ID Station Description Station Location A-North Perimeter Station A 62.51131,-114.33185 B-Town Perimeter Station B 62.49022,-114.35873 C-Northwest Perimeter Station C 62.5229,-114.34926 D-Beach Perimeter Station D 62.49748,-114.34496 E-A1C1 Perimeter Station E 62.49459,-114.36899 F-Marina Perimeter Station F 62.48592,-114.36093 G-West Perimeter Station G 62.50639,-114.365 H-Northwest Pond Perimeter Station H 62.51944,-114.3625 I-South Pond Perimeter Station I 62.49994,-114.34744 5-6 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Environmental alarms, called Risk-Based Action Levels (RBAL’s) act as a trigger to initiate dust suppression activities and/or cease intrusive work for the protection of the general public. It is understood that the primary soil contaminant at the project site is arsenic, however, real-time measurement of arsenic is not possible. As such, arsenic is represented by PM10. The rationale and calculations on which the RBAL’s are based are detailed in the AQMP. Perimeter (RBALs): Dust-PM10 (<10 µm diameter) = 159 µg/m³ Dust TSP (<100 µm diameter) = 333 µg/m³ Perimeter monitor concentrations are averaged over 15-minute periods. 5.3.2.1 Response to Perimeter RBAL Exceedance If the Risk-Based Action Level (RBAL) is exceeded for a perimeter station, the Air Quality Monitoring contractor is automatically notified via a system alarm, which prompts them to visit the site of the exceedance immediately to investigate the source. The air quality management contractor then communicates to the MCM and PSPC/CIRNAC to report their findings. The MCM then initiates corrective actions as necessary to control the source of the dust. (If the source of the exceedance is found to be equipment error or meteorological such as ice fog the air quality contractor also communicates this information to the MCM.) The perimeter data is then monitored by the Air Quality Monitoring contractor to ensure that the concentrations are declining. Data collected at the community stations is reviewed alongside site perimeter data to establish if the dust exceedance observed on site has migrated off-site. (See the GMRP AQMP for further details.) The Air Quality Monitoring contractor may also liaise through the MCM with other contractors working in areas of the site where air quality results are below actions levels, to assist contractors in evaluating their dust control/abatement measures. When safe to do so, suppression and additional mitigations will be implemented, following the procedures outlined for a Dust Event (Table 5.2-1). 5.3.3 Community Monitoring Community Air Quality monitoring stations provide continuous monitoring of PM10 and PM2.5, recorded hourly and averaged over 24-hours,, as well as analytical filter-based concentrations of antimony (Sb), arsenic (As), asbestos, lead (Pb), iron (Fe), nickel (Ni), total suspended particulate (TSP) and Particulate Matter of 10 micrometers or less in diameter (PM10). See the AQMP (AECOM 2019) for further details on ambient air quality criteria for community air quality monitoring stations. There are three community monitoring locations (Table 5.3-2): Table 5.3-2 Community Monitoring Station Locations Station ID Station Description Station Location NDL Ndilo Community Station 62.47562,-114.33795 YKB Yellowknife Bay Community Station 62.48593,-114.36094 NVN Niven Community Station 62.46509,-114.37318 5-7 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan 5.3.3.1 Response to Community RBAL Exceedance Should an exceedance of the community stations occur, an investigation will be undertaken immediately to determine whether the exceedance is from site activities, regional issues (i.e., forest fire), or local source such as road dust, and to evaluate the need for additional mitigation measures. The MCM and CIRNAC/PSPC would be notified immediately of any exceedance at a community station regardless of the cause. See the AQMP (Appendix F) for further details on actions as the result of an RBAL exceedance. 5.4 Contingencies The MVLWB letter of submission requirements issued to the GMRP after the Environmental Assessment (MVLWB, 2014) and the MVLWB Standard Submission Guidelines (MVLWB, 2013) require contingency scenarios to be included in all management plans. Contingencies are defined by the MVLWB as a description of how the results of monitoring will be linked to those corrective actions necessary to ensure that a component continues to meet objectives, applicable policies, and is operating as designed. The GMRP maintains an internal risk registry. This registry identifies all existing potential risks associated with the site, and ranks them for acceptability. Risks may be associated with aging infrastructure, weather events, or other management concerns. Risks are tracked and managed through monitoring programs and implementation of mitigations. Risks that are deemed unacceptable are addressed. Good examples of past responses to unacceptable risks, are the demolitions of the Roaster Complex, A-Shaft headframe, and C-Shaft headframe; infrastructure monitoring deemed these buildings to have an unacceptable level of risk to human health and the environment and they were, therefore, deconstructed prior to more serious consequences occurring, such as structure collapse. The GMRP has developed contingency scenarios for each management plan based on identified potential risks. In following the Board’s definition for contingency and following the methods implemented to date in managing risks, each contingency scenario outlines: • a risk statement – a risk identified at the site; each management plan includes risks specific to the area of management; • the phase(s) of the GMRP it applies to (See Section 1.3 for GMRP Phase discussion) • mitigations and monitoring undertaken regularly to monitor the identified risk; • an action level – the point at which the contingency scenario is initiated; and • a contingency or response – what the GMRP will do should an action level be reached for a specified contingency. In addition to the known existing risks and contingencies, the GMRP is completing a Quantitative Risk Assessment (QRA; ongoing at the time of submission). The QRA is working to identify all the potential risks that will remain at the site after remediation is complete. It will also identify the level of risk associated with each (low, medium, or high). Contingency scenarios will be developed for the risks identified in the QRA once complete. Risks will be updated in each management plan, as is relevant, moving forward. 5-8 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Appendix D includes a table of draft contingencies specific to dust management and monitoring. These scenarios and corresponding proposed action levels and responses are currently in draft form. Updated contingency scenarios will be provided with the updated management plans after issuance of the Water Licence. 5-9 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan PHASE 2 – ACTIVE REMEDIATION AND ADAPTIVE MANAGEMENT (Implementation of the approved closure activities) January 2019 GCDOCS # 31903347 Giant Mine Re1nediation Project Dust Management and Monitoring Plan 6 DUST MANAGEMENT AND MITIGATION – PHASE 2 As the project moves forward into active remediation, the breadth and scale of activities will increase, and many activities will be carried out concurrently (see Figure 1.3-1 for relative timing). 6.1 Anticipated Dust Sources In addition to managing existing site facilities, any work activity that will disturb soil or tailings requires that on- going and activity-specific dust controls and monitoring be in place. A final Design and Construction Plan for each planned activity requiring an engineered design or specification will be submitted to the Board for approval, prior to commencement. Each submission will include specific dust-related mitigation measures and monitoring based on the practices outlined below, and will in many cases be combined or amalgamated with erosion and sediment controls to prevent water erosion during site activities as well (Erosion and Sediment Management and Monitoring Plan). Final Design and Construction Plans will be made available for stakeholder consideration. The specific short-term construction and remediation activities that may cause significant increases in dust are divided into five main categories (Table 6.1-1). Table 6.1-1: Activities Requiring Dust Management - Phase 2 Activities Requiring Dust Management Earthworks • quarrying of borrow materials and associated rock crushing • excavation and placement of contaminated soils in pit and tailings ponds • excavation and movement of tailings for paste production and remediation • construction of the on-site landfill and covers over contaminated materials • windblown erosion of exposed in-situ or stockpiled soils, borrow materials, and tailings • development of temporary access roads • removal of up to 30 km of roads and utilities Infrastructure Demolition • disturbance of friable materials such as asbestos. • grinding, cutting or breaking of non-friable and other materials. • waste material handling. Drilling • geotechnical drilling • boreholes for equipment placement • boreholes for concrete delivery underground Blasting • blasting for borrow • works for Baker Creek realignment and floodplain Roadworks • grading and contouring of existing roads • use and maintenance of existing roads to support remediation and monitoring activities 6.2 Dust Risk Assessment Methodology Understanding the dust potential of remediation activities in a given area allows for proper mitigation measures to be implemented. The appropriate level of cost and effort to be expended in mitigation must be commensurate to the level of risk associated with a project component. 6-1 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Risks associated with activities at site can be generally described in the context of: a. likelihood of dust occurrence as a result of an activity, b. level of contamination where that activity is taking place, c. consequences of dust migration to nearby values at risk. This assessment, which will be activity- and location-specific, will serve to inform the level of effort of dust suppression, mitigation, and monitoring to be undertaken. These assessments will also be influenced by seasonality (e.g. – snow cover or precipitation) and other site-specific factors. 6.2.1 Dust Generating Activities As described in Table 6.1-1, numerous site activities are anticipated to be potential sources of dust that will require mitigation. For practical purposes, key activities can be ranked according to the likelihood and/or degree of dust generation (Figure 6.2-1). This list is not exhaustive; judgement must be used to determine the likelihood that an activity will generate dust and the activity rated accordingly. For example: Figure 6.2-1: Activities Ranked by Likelihood of Producing Dust. ACTIVITIES 10 QUARRYING AND PROCESSING 9 EXCAVATION OF TAILINGS > > 8 EARTHWORKS/ROADWORKS 7 BLASTING 6 MOVEMENT OR HANDLING OF DEMOLITION WASTES INFRASTRUCTURE DEMOLITION AND 5 CONSOLIDATION 4 DRILLING 3 CONSTRUCTION ------TRAFFIC/GENERAL ACTIVITIES - NO Likelihood of Dust Generation Dust of Likelihood 2 SNOW ACTIVITIES UNDER SNOW COVER/WET CONDITIONS 1 As likelihood of dust generation increases, a greater emphasis is placed on proactive and preventative dust mitigation (See also Table 6.2-1). 6.2.2 Soil Characteristics and Contamination In addition to the activity’s likelihood of creating dust, each activity-specific plan must take into consideration the location, and soil type and chemistry where the activity will take place. Existing soil chemistry, types, and arsenic loading of various site components are detailed in Figure 2.3-6 andFigure 2.3-7. These figures should be used in conjunction with Table 6.2-1 to determine the soil fragility and arsenic loading at the location of the anticipated activity. 6-2 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Arsenic concentrations are separated into four concentration levels: 1. 0-340 mg/kg 2. 340-3000 mg/kg 3. 3000-4500 mg/kg 4. 4500+ mg/kg This value is used to complete the assessment in Table 6.2-1. 6.2.3 Selection of Mitigation Measures Based on the information collected in this section, project managers will be able to determine the types of mitigation measures that must be considered. BMP’s should be selected according to the highest value assigned to any aspect of the activity or location. In other words, if any aspect rates ‘high’, the mitigation plan for that activity should consider Scheduling and Staging, Short-term Suppressants, and Physical Coverings. Table 6.2-1: Risk Rating and Required BMPs Required BMPs Likelihood of Dust Generation Contamination Values at Risk Rating Activity Type Soil Type Arsenic Loads Values at Risk Scheduling & Staging Short Term Suppressants Coverings Physical ReductionWind ● Quarrying and ● Silt Processing Very High ● Silty Loam ● Excavation of Tailings 4500+ mg/kg Risk 4 ● Loam ● Silty Sand ● Other Earthworks ● Sandy Loam ● Activity immediately ● Blasting ● Silty Clay Loam adjacent to water High Risk ● Movement or Handling of 3000-4500 mg/kg 3 ●Sandy Clay Loam body or other Values Demolition Wastes ● Silty Clay at Risk ● Sandy Clay ● Infrastructure Demolition ● Activity upwind but ● Clay Moderate and Consolidation > X distance from ● Heavy Clay 340-3000 mg/kg Risk 2 ● Drilling water or other Values ● Loamy Sand ● Construction at Risk ● Sand ● Traffic / General Activities ● Activity downwind ● Poorly graded Gravel Low Risk ● Snow Clearing from water or other 1 ● Well graded Gravel 0-340 mg/kg ● Sampling Values at Risk 6-3 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan 6.3 Dust Management Best Practices – Phase 2 All mitigations and practices proposed for Phase 1 (Section 4) will be continued in Phase 2. While detailed design plans are still in development, the BMP’s established for Phase 1 will be implemented. These will be updated in future plans as detailed designs are finalized. 6.3.1 Exposed Tailings Short-term dust suppressants will be employed until the Tailings Containment Areas are covered and reclaimed. • An approved soil stabilizer is added in the spring and as needed throughout the year. • Tailings are not disturbed once the coating has been applied. • Tailings are left as wet as possible to prevent wind erosion. • Water or suppressant can be re-added as needed. • Tailings are frozen in place/snow covered through the winter months. • Tailings work may be suspended when a Level 2 wind or dust level is reached except to monitor and stabilize (Tables 5.1-1 and 5.2-1). • Phase 2 activities will include the construction of engineered covers for the TCAs. Temporary physical covers (e.g. tarps), and wind control measures may be considered in the interim, on an as- needed basis. 6.3.2 Roads and Roadworks Prevention of dust from roads is accomplished through the use of short-term dust suppressants and procedural mitigation measures (staging): • Application of an approved dust suppressant in spring and summer and as needed. • Roads are watered between applications of approved dust suppressant. • Road and surface disturbances are minimized through proper road maintenance. • Road maintenance (grading and repair) is curtailed during high wind conditions. • Controlling vehicle/equipment speeds to 25 km/h or less on all roads with the exception of specific sections where speeds up to 40 km/hr are permitted. • Controlling vehicle/equipment speeds to 15 km/h around buildings and work sites. • Restricting traffic to designated roads/corridors, as needed. • Reducing disturbance when Level 3 wind or dust level is reached except to monitor and stabilize roads. • Driver training. • Washing of vehicles and equipment prior to leaving contaminated areas. 6-4 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan A Traffic Management Plan will be developed for the site as a result of the Giant Mine Environmental Agreement, 2015. Wind control measures may be considered if recurring issues arise. 6.3.3 Earthworks Standard practices to minimize dust during earthworks activities focus on scheduling and staging, and short-term dust suppression: • Consultation of a site arsenic contamination map prior to earth moving. • Minimize unnecessary disturbance. • Soil or tailings are wetted down prior to, during, and after to prevent wind erosion. • Excavated piles of soil or tailings are graded and contoured to be kept low (20° to 40°) or covered with other material to prevent drying. • Soil excavation may be suspended in high wind environments (Level 2 or 3) and exposed piles are watered to prevent wind erosion (see Table 5.1-1). • Machinery used for soil or tailings disruption is to be appropriately sized for the level of effort, to minimize soil disruption as much as possible. • Respect relevant Road Dust mitigation measures while carrying out earthworks. Additional dust control best practices that may be applied during one or more of the earthworks activities planned for remediation may include wind control measures and temporary physical covers: • Use of tarps or tackifier when transporting loads. • Using engineering controls such physical coverings. • Placement of non-erodible elements to reduce wind speed. • Use of wind fences. • Use of snow and ice. • Application of straw mulch or crop residue to limit erosion during a specific activity. 6.3.3.1 Excavation of Tailings for Paste and Remediation The use of tailings for paste production has been a large part of the Site Stabilization Work at site; paste is used to stabilize the underground mine stopes, chambers and bulkheads. Additionally, tailings will be consolidated from the South Pond to the North and Central Ponds. In addition to the Earthworks mitigation measures outlined above, these mitigations will be implemented when working with tailings: • Tarps or a soil tackifier are used when transporting tailings and placing tailings on stockpiles. • A tent is set up near the Tailings Reprocessing Plant for paste production for protection from wind and to reduce tracking to other parts of the mine site. 6-5 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan • Tailings excavation may be suspended high wind environments (Level 2 or above), and exposed piles are watered to prevent wind erosion. Additional dust control measures may be applied as outlined in earthworks activities. 6.3.3.2 Quarrying/Borrow Extensive borrow materials will be sourced from within the Project boundary for various reclamation activities. In addition to the Earthworks mitigation measures outlined above, this activity will require specific scheduling, active dust suppression, and may incorporate wind control measures: • Operate within acceptable wind speeds/direction (see Table 5.1-1). • Irrigation of the crushing/screening process with water. • Use of wind screens (both up-wind and down) around quarries to block wind and reduce dust spread from blasting and crushing, particularly where activities are conducted near Baker Creek. • Materials will be kept wetted for loading/transport as per earthworks BMP’s. 6.3.4 Infrastructure Demolition and Consolidation The following general mitigation measures for demolition focus on scheduling and staging, and short-term dust suppression: • Timing: planned for periods when temperatures are above freezing to allow for water use. • Timing: planned for periods when forecasted winds are low and favourable direction to minimize potential impacts to communities. • Minimize any material drop heights to reduce dust emissions. • Water and dust suppressants will be applied. • Continual air monitoring will be employed, either through perimeter air quality monitoring or in combination with activity-specific air quality monitoring. • Spray water will be utilized to control dust emissions loading, moving, or consolidation of debris stockpiles. • Bagged hazardous wastes will be inspected to ensure the containers are properly sealed and cleaned before they are removed from containment. • Debris stockpiles will be wetted or covered to prevent dust generation and to protect the debris from wind and treated with other mitigations appropriate to earthworks. All structures will be assessed, and contaminated structures will be decontaminated prior to demolition using arsenic and asbestos abatement measures as were implemented in demolition of the Roaster Complex. All water will be collected and managed within the footprint of each building and disposed of appropriately according to the Waste Management and Monitoring Plan (CIRNAC and GNWT 2019d). Non-hazardous and hazardous 6-6 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan waste will be disposed of according to the Waste Management and Monitoring Plan (CIRNAC and GNWT 2019d). Specific procedures will vary with the type, location, and amount of hazardous materials present in the buildings being deconstructed. The onsite contractor will be required to develop operating procedures specific to each building or group of buildings (e.g., the townsite), which adhere to these and other Board approved Guidelines. 6.3.5 Drilling Short-term dust suppression will be the predominant mitigation during drilling: • Wet drilling involves the use of water combined with air to flush drill cuttings, preventing dust generation through the capture of dust particles in drilling water. • Drill water will be collected and managed according to the Waste Management and Monitoring Plan (CIRNAC and GNWT 2019d). • Dry drilling involves the use of a dust collector during drilling. • Should a dry drilling method be implemented due to the timing of the year, cuttings will be wetted to ensure they do not become airborne. Timing of the activity will be dependent upon the timing of the year and wind speeds, and additional measures may be added if concerns arise as to the anticipated contaminant levels in the dust. 6.3.6 Blasting While blasting itself may generate dust, the major source of dust will be from the crusher while it is operating. • Operate within acceptable wind speeds and direction (Table 5.1-1). • Blasting best practices: use of blasting mats, blasting hole patterns, limiting the size of the blast, “stemming” the hole with sand, and factoring in wind speed and direction when planning and executing blasting. Blasting underground: • use of water misters • legal requirement to wash down areas after blasting in order to settle the dust 6-7 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan PHASE 3 – POST-CLOSURE MONITORING AND MAINTENANCE (long-term monitoring and maintenance after all site remediation is complete) January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan 7 POST-CLOSURE MONITORING AND MAINTENANCE Remediation is anticipated to take approximately 10 years to complete. The post-closure phase is expected to commence in 2031. A Post-Closure Monitoring and Maintenance Plan (PCMMP) is required to be submitted prior to entering a state of post-closure. This PCMMP will provide a detailed description of all management, anticipated maintenance, and monitoring that will continue post-closure, linking required monitoring and maintenance to the GMRP Long-Term Monitoring Plan (LTMP). It is fully expected that the MVLWB and its reviewers will govern and provide input on a post-closure management plan once Phase 2 nears completion, and throughout Phase 3. 7.1 Sources of Dust During Adaptive Management (the latter part of Phase 2), remediation activities will be monitored, assessed, and adjusted as necessary to ensure their success in eliminating sources of dust and contaminants. As such, sources of dust post-closure should be limited to roads and laydown areas used to support long-term monitoring and maintenance. 7.2 Monitoring and Contingencies Dust monitoring will continue to determine whether dust from roads and laydown areas used to support long- term monitoring and maintenance at the Site requires mitigation. Should Phase 3 air quality monitoring demonstrate air quality at the Site to be similar to background levels, and dust monitoring confirms no significant dust sources remain at the Site, the air quality monitoring program may be scaled back or discontinued after consultation with affected parties. 7-1 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan 8 REPORTING, REVIEW AND LINKAGES - ALL PHASES 8.1 Reporting In accordance with the Annual Water Licence reporting requirements, the GMRP will submit a summary of dust management and monitoring activities conducted during the previous calendar year, in accordance with this Dust Management and Monitoring Plan, once approved. The Annual Water Licence Report provides a holistic summary of all on-site activities throughout the entire year. It helps to identify how different actions taken with respect to dust management may have impacts on other on-site monitoring and management, such as erosion control (Refer to Section 1.3.4 for linkages to other plans). 8.2 Required Review and Updates The existing dust management practices at the site have been reviewed by stakeholders and approved by the Board in previous management plans, including the dust management plan submitted for Site Stabilization activities MV2012L8-0010. In addition, Section 5.12 in the CRP provides a high-level outline of all management and monitoring planned for each phase of the GMRP (CIRNAC and GNWT, 2019a). This Dust Management and Monitoring Plan has been submitted as a supporting document to the GMRP Post-EA Information Package. The GMRP is requesting that Phase 1 of this plan be approved conditionally upon licence issuance; an updated version will be submitted within 90 days of Water Licence issuance if updates are needed based on the outcomes of the proceedings. Once the water licence is issued, standard conditions require annual reviews of all management plans; should updates be necessary, an updated plan is to be submitted to the MVLWB for public review and approval. For the GMRP specifically, it is anticipated that management and monitoring plans will require update on a regular basis, in response to updated information provided in Design and Construction Plans. The schedules for content of Design and Construction Plans, proposed in the draft Water Licence require the following monitoring and contingency information to be provided for all closure activities or constructed components implemented on site (part of Schedule 3, Conditions 1-3): Design and Construction Plan Components related to Management and Monitoring Plans Activity-specific monitoring and • monitored components; mitigation details for the Construction • sampling locations, parameters measured, and sampling frequency; period and post the- • reference to any associated monitoring program, including where and how Construction/adaptive management results will be analyzed and reported; and monitoring period. • an explanation of how proposed monitoring will assess the risks identified in Schedule 3, Condition 1(g); • linkages to applicable closure objectives and criteria; • linkages to existing management and monitoring plans and programs; and • any other monitoring details required to monitor and mitigate impacts to the Receiving Environment. A description of contingency • Identified risks related to achievement of the closure or performance activities that will be undertaken if criteria; monitoring results show that • A threshold or action level which defines the point at which monitoring Engineered Components are not indicates a response is necessary; and meeting closure criteria or are not • The proposed response to be implemented if threshold exceeded. satisfying performance criteria. 8-1 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan In addition, final closure criteria are to be proposed, if needed; operational requirements and any anticipated maintenance, is to be outlined, design details, construction considerations including a QA/QC, and any applicable background information must be included. For a full review of schedule details refer to Part E of the proposed Water Licence. Once construction is completed, Construction Completion Reports and Performance Assessment Reports must be submitted, developed in accordance with the Reclamation Completion Report requirements in the MVLWB (2013) Guidelines for the Closure and Reclamation of Advanced Mineral Exploration and Mine Sites in the Northwest Territories and outlined in Part E of the Proposed Water Licence. In addition to Guideline requirements, these two reports have been developed to allow the GMRP to propose updates to monitoring, contingencies, and maintenance requirements, if needed. Any updates require Board approval prior to implementation. Figure 8.2-1 depicts the connection between these three construction-related plans and management and monitoring plans. In consideration of the information to be provided in Design and Construction Plans and Construction Completion Reports, several sections of this management plan may be updated as the GMRP progresses through remediation including: • Dust sources • Proposed mitigation measures • Monitoring details • Contingencies Once updated, plans will be submitted to the Board. Any management and monitoring details not approved by the Board in the Design and Construction, Construction Completion reports, or Performance Assessment Report, requires Board approval. A conformity table which outlines all updates will be included in each new version being submitted to assist with review and approval. 8-2 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Figure 8.2-1: Linkages between CRP, Construction-related Plans, and Management and Monitoring Plans Approved details to be incorporated into updated CRP Submit Design and Submit Performance Construction Plans Assessment Report Detailed Design complete; Review of implemented closure activity ready for Includes any final closure ------•- closure option and implementation criteria, activity-specific monitoring, detailed identification of any design, etc. required maintenance Update Management Implement and Monitoring Plans Includes site-wide and activity specific monitoring Submit Construction Completion Report As-built; may include updat ed monitoring details Licence ReP.ort lncluaes summai:y of CRP. Progress to be reported through progress ana monitoring Annual Report result s 8-3 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan 9 REFERENCES AANDC (Aboriginal Affairs and Northern Development Canada) 2006. Contaminated Sites Environment, Health and Safety Policy prepared by Aboriginal Affairs and Northern Development Canada (April 13, 2006); https://www.aadnc-aandc.gc.ca/eng/1100100035307/1100100035308 AECOM 2019. Giant Mine Air Quality Monitoring Plan. AECOM 2013. Giant Mine Air Quality Monitoring Plan. Arcadis. 2013. Memo: Regarding: Real-time Fenceline Monitoring Risk-Based Action Level (RBAL) for PM10. CIRNAC and GNWT 2015. Giant Mine Remediation Project Environmental Agreement. June 9, 2015. http://www.enr.gov.nt.ca/sites/enr/files/giant_mine_environmental_agreement_signed_june_2015.pdf CIRNAC and GNWT. 2019a. Giant Mine Closure and Reclamation Plan. Prepared for the Mackenzie Valley Land and Water Board, Yellowknife, NT, Canada. January 2019. CIRNAC and GNWT. 2019b. Giant Mine Erosion and Sediment Management and Monitoring Plan. Prepared for the Mackenzie Valley Land and Water Board, Yellowknife, NT, Canada. January 2019. CIRNAC and GNWT. 2019c. Giant Mine Tailings Management and Monitoring Plan. Prepared for the Mackenzie Valley Land and Water Board, Yellowknife, NT, Canada. January 2019. CIRNAC and GNWT. 2019d. Giant Mine Waste Management and Monitoring Plan. Prepared for the Mackenzie Valley Land and Water Board, Yellowknife, NT, Canada. January 2019. CCME (Canadian Council of Ministers of the Environment) 2012a. Guidance Document on Air Zone Management. CCME 2012b. Achievement Determination Canadian Ambient Air Quality Standards for Fine Particulate Matter and Ozone. ECCC 2017. Canadian Climate Data. Available at: http://climate.weather.gc.ca/historical_data/search_historical_data_e.html ECCC 2005. Best Practices for the Reduction of Air Emissions from Construction and Demolition Activities, Cheminfo Services Inc. prepared for Environment Canada, Transboundary Issues Branch GNWT (Government of the Northwest Territories). 1998. Guideline for the General Management of Hazardous Waste in the NWT prepared by Government of the Northwest Territories (February 1998); http://www.enr.gov.nt.ca/sites/enr/files/guidelines/general_management.pdf GNWT 2004. Guideline for the Management of Waste Asbestos. Environment Division, Department of Environment and Natural Resources, Northwest Territories. GNWT 2010. General Guidelines for Asbestos Removal and Disposal. Northwest Territories Public Works and Services Department. 9-1 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan GNWT 2013. Guideline for Dust Suppression. http://www.enr.gov.nt.ca/sites/enr/files/guidelines/dustsupression.pdf GNWT. 2014.Guideline for Ambient Air Quality Standards in the Northwest Territories. Northwest Territories Environmental Protection Act INAC and GNWT (Indian and Northern Affairs Canada and Government of the Northwest Territories). 2010. Giant Mine Remediation Project Developer’s Assessment Report. Submitted to the Mackenzie Valley Impact Review Board, Yellowknife, NT, Canada. Kokelj SV, Spence C., Kokelj S. 2012. Changing Hydrological Regimes – Baker Creek: Results, Implications and Next Steps. Submitted to the Giant Mine Team by AANDC and ECCC. Accessed at: http://sdw.enr.gov.nt.ca/nwtdp_upload/GIANT_report_April%202012_pdf. MVLWB (Mackenzie Valley Land and Water Board) 2013. Standard Outline for Management Plans. https://mvlwb.com/sites/default/files/documents/wg/Standard%20Outline%20for%20Managment%20Pla ns%20-%20October%202013.pdf MVLWB 2013. Guidelines for the Closure and Reclamation of Advanced Mineral Exploration and Mine Sites in the Northwest Territories. https://mvlwb.com/sites/default/files/documents/wg/WLWB_5363_Guidelines_Closure_Reclamation_WR .pdf MVLWB 2014. Submission Requirements for Mining and Milling Water Licence and Land Use Permit Applications – Giant Mine Remediation Project – Yellowknife, NT. Letter from Zabey Nevitt, Executive Director, MVLWB, to Adrian Paradis, Regulatory Manager GMRP – AANDC. 20 August 2014. OMOE (Ontario Ministry of the Environment) 2012. Ambient Air Quality Criteria. OMOT (Ontario Ministry of Transportation) 2015 Environmental Guide for Erosion and Sediment Control During Construction of Highway Projects. http://www.raqsb.mto.gov.on.ca/techpubs/eps.nsf/0/7FF7C9FA7DEF430F85257F5B00510665 RWDI AIR Inc. Giant Mine Remediation. Fugitive Dust Assessment. Final Report. May 4, 2016. Royal Meteorological Society. 2018. The Beaufort Scale. Accessed 23 January 2018 https://www.rmets.org/resource/beaufort-scale SENES. 2012. CALPUFF Air Dispersion Modelling for the Giant Mine Remediation Project. March 2012. SLR (SLR Consulting [Canada] Ltd.). 2015. Air Quality Monitoring Program Annual Report – 2014. Giant Mine Remediation Program. Public Services and Procurement Canada. Yellowknife, NT, Canada. SLR. 2017. Air Quality Monitoring Program Annual Report – 2015. Giant Mine Remediation Program. Public Services and Procurement Canada. Yellowknife, NT, Canada. 9-2 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan SLR. 2018. Air Quality Monitoring Program Annual Report – 2016. Giant Mine Remediation Program. Public Services and Procurement Canada. Yellowknife, NT, Canada. SRK (SRK Consulting [Canada] Inc.) 2016. Giant Mine Remediation Project Surface Design Engagement Options Evaluation Workshop. Report prepared for INAC. August 2016. US EPA “Ambient Air Monitoring” https://www.epa.gov/air-quality-management-process/ambient-air-monitoring. Updated March 17, 2017. WSCC 2012. Codes of Practice for Asbestos Abatement WSCC 1997. Asbestos Safety Act. Northwest Territories Safety Act. 9-3 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan APPENDICES January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan APPENDIX A CONFORMITY TABLE January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Water Licence MV2007L8-0031 Corresponding Section in Management Plan Part G, condition 5: A minimum of 90 days prior to the commencement of n/a Reclamation, the Licensee shall submit a Dust Management and Monitoring Plan to the Board for approval. The plan should seek to minimize the amount of dust blowing into local communities as per Approved EA Measure 20. The Plan shall satisfy the requirements of Schedule 3, Condition 3. The Licensee shall not commence Site Reclamation until the Board has approved the Plan. Schedule 3, Condition 3: The Dust Management and Monitoring Plan referred to in Part G, Condition 5 of this Licence shall include, but not be limited to, the following: a) Information regarding potential dust dispersion on site: i A summary of meteorological information related typical to wind Section 2.3 directions and speeds at the site; ii A summary of relevant findings from the Air Quality MonitoringSection 5.3 Program as they relate to dust deposition at site; iii A description of potential extreme meteorological events that couldSection 5.1 influence dust dispersion from the site with recommendations for wind conditions under which any dust-generating activities should be halted in order to minimize the chances of dust and contaminants blowing into the City of Yellowknife, Dettah and Ndilǫ; b) Information regarding dust control and mitigation methodologies: i A summary of the types of site activities that could generate dust; Sections 4.1, 6.1, 7.1 ii For each of the activities identified above, a description of the best Sections 4.2, 4.3, 6.3 , management practices or mitigations that may be employed minimize 9.3 the generation of dust; iii Any other information required to describe how the Licensee will This plan minimize the release of dust and contaminants from any part of the site into the Receiving Environment. c) Information about monitoring including: i. Details for monitoring, including rationale, that will be undertaken with Sections 5, 6 respect to dust generated from the site; ii. an explanation of how proposed monitoring will assess the risks identified Sections 5, 6 in Schedule 3, Condition 3(d) iii. Linkages to other monitoring programs and the Construction Plans and Sections 1.3.4, 8 Construction Completion Reports required in this Licence; d. A description of maintenance or contingency activities that will be Sections 5.4 undertaken if monitoring results show that dust management systems are not meeting Part G, Condition 1 of Licence this . The contingencies section of the Dust Management and Monitoring Plan will include: i.Identified risks related to dust management for each phase of the GMRP; ii. A threshold or action level to define the point at which monitoring indicates a response is necessary; and d) Proposed response to be implemented if threshold exceeded. e) Corrective and preventative actions taken during the year shall be reported in Section 8 the Annual Water Licence Report as per Part B, Condition 10 of this Licence. January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan APPENDIX B MCM CONTACT INFORMATION January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Role Name Company Phone Number Office/Cell Phone: 867- Mine Manager Doug Hayes Parsons 669-3715/867-688-1036 Senior Project Manager Dayal Madhavan Parsons Cell Phone: 403-620-1588 Site Superintendent Daniel Mathes Parsons Cell Phone: 403-607-0648 Office/Cell: 867-669- Underground Superintendent Mark Schmaltz Parsons 3704/ 867-688-3297 Office / Cell Phone: 867- Environmental Manager Carolina Mora Parsons 669-3725 / 867-688-3352 Office Phone: 867-669- Health and Safety Manager Lex Lovatt Parsons 3719 Office Phone: 867-669- Security Manager Lex Lovatt Parsons 3719 Office Phone: 867-669- Medical Manager Lex Lovatt Parsons 3719 January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan APPENDIX C GIANT MINE ENVIRONMENT, HEALTH & SAFETY, AND COMMUNITY POLICY January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Giant Mine Remediation Project Environment, Health, Safety and Community Policy Policy Owner: Environment, Health, Safety and Community Manager Approval Date: February 2014 Preamble: As committed to in the Developer’s Assessment Report and during the Environmental Assessment Public Hearings, the Giant Mine Remediation Project (GMRP) will develop and implement an “Environmental Management System” that conforms with the requirements of ISO 14001 – the international Environmental Management Standard. Based on best practice in public sector operations and the mining sector, the GMRP has expanded the scope of the management system to include safety and community aspects. This policy was developed with input from engaged stakeholders and will guide the management of environment, health and safety and community aspects and issues for the duration of the project. Purpose: This Policy sets commitments for the management of environment, health and safety, and community (socio- economic and engagement) for the Giant Mine Remediation Project (GMRP). These commitments will guide the development and implementation of an integrated Environmental, Health, Safety and Community (EHSC) Management System that describes planning for, execution and continuous improvement of the environmental, health and safety, and community management and performance of the GMRP. Policy Statement: The GMRP is committed to: • Protecting the environment and the health and safety of its employees; contractors and the general public; • Engaging meaningfully with stakeholders; • Delivering local social and economic benefits; and • Being a recognized leader in EHSC management among public environmental remediation projects. • To this end, GMRP will act in a manner that minimizes its negative impacts, maximizes its positive benefits, and continually seek ways to improve its performance. Overall Commitments In order to achieve these objectives, the GMRP is committed to the following: • The GMRP will plan and execute in a manner that respects and cares for people and the environment. • The GMRP will comply with all applicable environmental, health and safety, and community (socio- economic and engagement) regulatory, policy and other requirements. • The GMRP will apply best management practices including best available technology and processes for environmental protection and public safety. • The GMRP will promote a project-wide culture committed to continual improvement in environmental, health and safety, and community guided by the EHCS Management System. January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Environment Commitments • The GMRP will continually evaluate and apply ways to responsibly govern the use of its resources and reduce its negative impacts on air, water, land resources and biodiversity. • The GMRP will minimize harmful releases of air contaminants, dust and halocarbons, and hazardous materials/dangerous goods. • The GMRP will minimize waste. • The GMRP will minimize disturbance or damage to heritage buildings, and Aboriginal archeological and burial sites • The GMRP will minimize harmful water and sediment discharges. • The GMRP will minimize disruption or damage to flora and fauna. 2 Health and Safety The GMRP will achieve excellence in health and safety performance through a zero harm target for employees, contractors and the public. 3 Community The GMRP will develop collaborative and mutually beneficial relationships with its stakeholders, and deliver local social and economic benefits. • The GMRP will communicate effectively with the public regarding the nature and status of the project. • The GMRP will meaningfully engage with stakeholders to address concerns and ensure that community land use expectations and traditional knowledge have been considered in closure planning. • The GMRP will implement strategies to maximize the economic opportunities for Northerners and local Aboriginal people through employment and procurement. • The GMRP will respect the rights of Aboriginal peoples. Persons Affected: This Policy applies to Federal and Territorial employees and contractors of the GMRP as well as visitors to the GMRP's operations. The GMRP will foster a culture that encourages safe, healthy and environmentally- responsible behaviour by clearly defining the responsibilities of all employees. Proactive employee involvement in these efforts will be encouraged. Roles and Responsibilities: Overall responsibility for the EHSC Policy rests with the Project Leader, Assistant Deputy Minister (ADM) Northern Affairs Program. The Management Board exercises due diligence with respect to this Policy through regular review, discussion and endorsement of EHSC Management Systems, strategies and action plans, as well as performance, incident and audit reports. The AANDC Giant Mine EHSC Manager is responsible for establishing and maintaining the practices, guidelines and internal controls pertaining to this Policy. All Project Employees are required to adhere to the principles of this Policy and will actively promote its adoption by contractors, suppliers, partners and agents. January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Policy Context: This policy is intended as functional guidance at the project level. It is ultimately subservient to existing policies and authorities in place at departmental and government-wide levels. This Policy is guided by AANDC’s CSP Contaminated Sites Management Policy (2006), Northern Contaminated Sites Program EHS Management Policy, and the Developer’s Assessment Report as well as the AANDC’s Sustainable Development Strategy. Commitments are guided by the critical strategic planning documents for the GMRP including the Project Charter, Project Execution Plan (PEP), and Performance Measurement Strategy, which is part of the PEP. January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan APPENDIX D CONTINGENCIES January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Risk Relevant Mitigations/Monit Initiation Point of Contingency/Resp Link to Other Statement Phases oring Contingency onse Plans •Formalized program of dust •Reapply management / suppressant and/or control and site- water wide AQMP •Stop work in high implemented: Tailings dust wind conditions •Regular from tailings •Install wind application of ponds blown blocks/physical suppressant and off site by •Wind events covers if necessary 1-2 water AQMP wind (with or •Visible dust events •Continuous air •Monitor wind without quality monitoring speeds activity along site perimeter •Minimize occurring) (during non-snow disturbance covered months) •Air quality and communities of monitoring Yellowknife and •Work in tailings Ndilo under low wind conditions •Monitor wind speeds •Formalized program of dust •Reapply management / suppressant and/or control and site- water wide AMP Extreme •Wind events •Stop work in high 1-3 implemented: AQMP wind events •Visible dust events wind conditions •Emergency •Install wind application of blocks/physical suppressant and covers if necessary water •Stop work •Air quality monitoring •Apply suppressant •Monitor wind and/or water to Structural speeds debris Collapse •Proactive removal 1-3 •Occurrence •Ensure health and AQMP produces of key structures safety of all persons dust •Air quality on/off site monitoringDRAFT •Use PPE January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan APPENDIX E BEST MANAGEMENT PRACTICES (FROM OMOT 2015) January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Scheduling and Staging Activities Best management practices for dust mitigation include the consideration of dust control in the scheduling and staging of activities. Optimizing the sequence for implementation of an activity will be within the purview of the selected contractor. The selected contractor will be required to outline its remediation schedule and staging plan for an activity it has bid on and been awarded. Dust Suppressants Currently there are exposed mineral wastes on site susceptible to erosion and therefore the potential for dry particles to become airborne. The largest of these areas are the tailings disposal areas, but roads and associated areas are also a large source of nuisance dust. Dust suppressants are compounds that can be applied to an erodible surface to hold it together such that it will resist wind erosion. Water can be considered as a dust suppressant, but there are also several commercially available chemical suppressants that can minimize wind erosion for extended periods. Water When fine-particulate soils or tailings are wet, the water adheres to the particles, thereby increasing their effective mass and surface tension forces. This has the effect of significantly decreasing the erodibility of a surface. The application of water can also result in the formation of natural aggregates and surface crusts that often persist after the water has evaporated (Watson et al., 2000 in RWDI, 2016). The efficacy of wet suppression is dependent on the amount of water applied per unit area, the time between applications, traffic volume/use of area during that time period, and prevailing meteorological conditions during application and the period following. Emissions from wet tailings (> 5 to 10% moisture content) are typically >95% lower than for dry tailings (McKenna et al., 2009 in RWDI, 2016). Therefore, the watering of a tailings area can be assumed to provide complete control over that area as long as its entirety can be kept moist constantly. To accomplish this, the rate of water application must be at least equal to the rate of water evaporation and infiltration. The actual amount of water application required can be computed from available weather records and will vary depending on the surface material, air temperature, wind speed, humidity and cloud cover. Chemical Dust Suppressants There are a variety of chemical dust suppressants available commercially. Most act very similarly by either agglomerating or binding fine particles together, or by forming a crust over the erodible surface thus preventing wind erosion of the underlying material. Essentially, chemical stabilization can either simulate a wet surface or a paved surface through attracting and retaining moisture or by cementing loose material into the surface, respectively (EPA 1992). The effectiveness of chemical suppressants is highly variable depending on the product but is generally at a maximum immediately following its application and then degrades with time. This rate of degradation is increased if the surface is disturbed, such as by vehicles driving on the crusts, or through surface cracking from freeze-thaw cycles. January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Salts such as magnesium or calcium chloride have also been used at facilities to keep tailings moist when snow or ice is present at temperatures as low as around -10°C. Applying these salts to the tailings area can help keep them moist for longer periods of time. They also allow the surface to absorb moisture at relative humidity levels above 50% (Watson et al., 2000 in RWDI, 2016). Similar to watering, this method can be assumed to control wind erosion by as much as 95% over the areas that can be kept moist. Salts however will eventually wash away with runoff from precipitation events and would need to be replenished. (summaries provided by RWDI, 2016 Report). Snow and Ice Cover In the winter, snow cover can reduce dust, as long as the erodible surface remains covered and the snow does not drift, which may leave some areas exposed (unprotected). Freezing of pore water in soils or tailings can also result in individual soil particles combining into frozen aggregates, reducing the likelihood of wind erosion. The application of additional snow on the tailings from snow removal at the facility can also be used to improve the effectiveness of snow and ice as a mitigation measure. Other mines in Canada have shown that mechanically compacting the snow covering exposed soils or tailings can increase the effectiveness of snow cover as a winter dust suppressant, by preventing the snow from drifting and also allowing it to melt more slowly in the spring, thus extending the protection period and resulting in improved short-term wetting of the soils and tailings upon melting. A heated water cannon can be employed to promote ice formation on exposed soils and tailings surfaces during winter months. This may be an effective method in support of dust and water erosion should a break in earthworks activities be implemented due to cold weather. Should earthworks be ongoing during winter conditions, and soil or tailings are being handled or moved, additional mitigations will need to be combined with this approach. Wind Reduction Non-Erodible Roughness Elements Covering an erodible surface with large (typically several 10’s of centimeters to meters in cross-sectional and frontal area) non-erodible elements causes the elements to absorb part of the momentum from the wind and thus protect the erodible surface. If the density of non-erodible elements is sufficiently high, they will absorb the majority of the momentum from the wind and the emissions from the protected erodible surface will be minimized. The required density of non-erodible elements over a tailings surface is dependent on the shape and surface area of the element being used. To achieve adequate surface protection, their vertically projected area ratio (the ratio of the frontal area visible to the wind to the total erodible surface area) should be approximately 2-5% (Marshall et al., 1971 in RWDI, 2016). This allows for the creation of a stagnant zone or ‘pocket’ in the lee of individual elements. A wide variety of non-erodible elements have been used at mine sites, including tires, straw bales, and rocks. This method can provide >90% control but is highly dependent on the size of the non-erodible elements and density of placement over the erodible surface. The particular element used is typically dependent upon cost and January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan local availability. For example, straw bales are not as readily available in Yellowknife as they are in other regions. However, rocks of different sizes can be generated on site and as such are a potential option. Given that are also a large number of disposed tires on site (> 1,000), and possibility of obtaining more from other sources, the use of tires as non-erodible elements during remediation may be worth consideration. Another form of non-erodible roughness element is the use of wind rows. This type of mitigation works along the same principles of other non-erodible roughness elements but in linear rows as opposed to a random placement that is typically adopted for discrete elements such as large rocks or straw bales. Wind rows are sometimes used at active mine sites where waste rock is being generated actively. Instead of dumping waste rock in a pit or pile it is deposited in rows on the tailings surface. Given the linear nature of wind rows, this approach lacks effectiveness for winds that are not essentially perpendicular to the row in the same way that wind fences are limited (Section 7.4). As rocks on site must be generated through blasting and crushing it is felt that if this level of effort is going to be employed it is likely more practical to deposit material in a thin layer across the entire surface than it is to generate wind rows as the former is expected to provide greater overall efficiency. Wind Fences Porous wind fences can be an effective means of reducing wind speeds and hence wind erosion downwind of the fence. Over flat ground, a 50% porous wind fence reduces the wind speed by more than 50% on the leeward side at distances of up to 12 or 15 times the height of the fence (Stunder et al. 1988 in GWDI, 2016). However, at farther downwind distances from the fence, the wind speed will increase back to its undisturbed speed. There are generally two different types of wind fences: those that are very large, engineered structures in excess of 10 m tall with a fabric or mesh suspended between large poles or stanchions; and, those that are much smaller (on the order of 2 m tall or less) and used as snow fences or similar purposes. The former kind of fence requires significant engineering (and often significant cost) in design and installation from the perspective of wind loading, stanchion installation, fabric, etc. Per the ratios provided above, a 10 m tall fence can reduce near-surface wind speeds in the lee by on the order of 50% for a distance of up to 120 or 150 meters. These types of fences are typically installed in space limited areas (e.g., along docks or property lines) where other options are not feasible and where winds tend to be unidirectional. Smaller porous structures such as snow fences offer protection to dust emitting surfaces through the same basic principles as larger fences. For greatest effectiveness, several wind fences typically need to be placed in rows at separation distances of up to 20 fence heights apart to cover the entire erodible surface area (i.e., rows of four foot tall snow fence can be installed up to 80 feet apart). Decreasing the separation distance to approximately 15 heights or 60 feet apart can provide further conservatism in terms of area protected and achieve on the order of 75-95% reduction in dust emissions over the protected surface. Note that with both types of fences, the rated effectiveness is only valid if the wind is blowing perpendicular to the fence(s). The relative effectiveness decreases drastically as the wind angle to the fence decreases, which supports the option of decreasing the spacing between rows. To provide mitigation in areas where there are two or three primary wind directions of concern, snow fencing installed in a saw tooth or ‘zig-zag’ pattern is sometimes used to mitigate both sand and snow drifting issues. However, there is no known report detailing how well this type of configuration might work for mitigating wind-blown dust. Further review and testing through field January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan trials, physical wind tunnel testing, or numerical simulation would likely be needed before further consideration for this type of approach is warranted. There are some other inherent benefits to exploring the use of snow fences that are worth consideration. Rough calculations suggest that several kilometers of fencing would likely be required to cover a given tailings area. However, the cost is relatively low for the fence material, as are the steel posts and mounting hardware. Although time consuming to install, the work can be done using light duty vehicles and involves primarily manual labour. All considered, the costs for snow fencing may be relatively modest. Another benefit to snow fencing is its ability to trap wind-blown snow within the tailings areas, resulting in a deeper snowpack and hence extension of the period during which snow cover protects the surface (Section 7.6). This may also play a minor role in increasing the wetted area of the tailings for a short period during the spring thaw. One potential downside to snow fencing is the need for relatively frequent maintenance to replace sections of fence, re-install posts, etc. It is also likely that the fencing material would have to be replaced after several years in the field. The expected frequency for replacement of fencing in Yellowknife is unknown but most likely available. The use of fencing can also result in wildlife becoming separated from its herd or pack or caught on the wrong side of a fence, especially when fencing in placed in low-traffic areas or along known corridors. Impacts to wildlife can be reduced through proper planning, wildlife deterrents, and monitoring. Although used in different configurations at a wide range of sites, the effectiveness of snow fences tends to be quite specific to the surface being protected (e.g., pile, material handling area, flat open surface), and wind regime (specifically the range of wind directions of concern) and therefore may vary in its applicability based on types and locations of earthworks activities during remediation. Physical Coverings Aggregate Cover Covering dust emitting surfaces with a non-erodible material would provide total (i.e., 100%) protection from wind erosion. As long as the covering remains intact, the wind would pass over the cover and the tailings below would be completely protected. The use of granular material such as gravel or cobbles as a surface coating or ‘armoring’ presents an option that can be very highly effective (> 95% efficiency). This is the long-term plan for the tailings ponds and pits: an engineered cover with multiple layers of fill material and rock will be placed over the tailings and the material placed in pits. Borrow material options for both gravel and cobble-sized materials are currently being assessed at the site. Some of the key benefits to using rocks are that they are native to the site, they are permanent, and they do not require maintenance. In addition, use of rocks to cover tailings and pits aligns with stakeholder input received through Surface Design Engagement (SDE) that the location of ponds and pits should remain visible as a reminder of what lies beneath. January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan Use of granular material as a physical barrier for short-term dust mitigation is not feasible. Use of other physical barriers, such as plastic sheeting is noted as temporary best management practice to provide short-term mitigation from wind and water erosion of stockpiles and smaller disturbed areas of exposed soils and tailings. Plastic Sheeting Plastic sheeting is inexpensive and easy to install. However, plastic sheeting can be vulnerable to lifting by wind and therefore is not recommended for more than short-term application. Edges of plastic sheeting must be property secured and overlapped to minimize wind disturbance; they should be inspected regularly and additionally after storm of high-wind events. Rolled Erosion Control Products Rolled erosion control products (RECPs), which can be biodegradable or synthetic soil coverings, are used for temporary or permanent protection of disturbed soils or tailings on slopes and channels. These include erosion control blankets (generally biodegradable and temporary), turf reinforcement mats (TRMs), and composite turf reinforcement mats. While RECPs have the added benefit of prevention of wind erosion, they are often used in support of revegetation efforts to protect seeds and stabilize soil temperature. Revegetation may be applicable to some areas of the site. Vegetation and Straw Mulch Vegetation is often used as a permanent erosion control solution. Vegetation controls wind erosion by absorbing part of the momentum from the wind and thereby protecting the erodible surface. Over time the roots from vegetation also help to stabilize the surface material. Although some vegetation may die in the winter, dead vegetation provides similar protection to living vegetation, as long as it remains intact. Vegetation has been applied to tailings at mines in the Northwest Territories with success, especially when native grasses have been used. Revegetation is a common closure practice, though expensive, and often mining projects rely on natural revegetation as a long-term solution, potentially with more medium-term erosion mitigations in place prior to establishment. As discussed previously, vegetation on tailings and pit covers has been identified as unfavorable from a social perspective, because some stakeholder groups have identified a desire for there to be a visual reminder of the project (SRK 2016) and therefore alternative tailings covers using granular material have been selected by the GMRP. January 2019 Giant Mine Re1nediation Project Dust Management and Monitoring Plan APPENDIX F GMRP AIR QUALITY MONITORING PLAN January 2019 Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Prepared by: Prepared for: AECOM Canada Ltd. Public Services and Procurement Canada 300 – 48 Quarry Park Blvd. SE 5th Floor, ATB Place North Tower Calgary, AB T2C 5P2 10025 - Jasper Avenue Canada Edmonton, AB T5J 1S6 T: 403 254 3301 F: 403 270 0399 www.aecom.com Date: February, 2019 Project #: 60577312 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Distribution List # Hard Copies PDF Required Association / Company Name Public Services and Procurement Canada AECOM Canada Ltd. Revision History Rev # Date Revised By: Revision Description 1 02Nov2018 JL/PT Revision of 2013 AQMP, Initial Draft 2 25Jan2019 JL/MG Draft with revisions 3 01Feb2019 JL/PS/MG Final 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx Imagine it. AECOM Canada Ltd. A:'COM Delivered. 300 – 48 Quarry Park Blvd. SE Calgary, AB T2C 5P2 Canada T: 403 254 3301 F: 403 270 0399 www.aecom.com Public Services and Procurement Canada February 1, 2019 5th Floor, ATB Place North Tower 10025 - Jasper Avenue Edmonton, AB Project # T5J 1S6 60577312 Subject: Giant Mine Remediation Project – Air Quality Monitoring Plan AECOM Canada Ltd. is pleased to submit this report to Public Services and Procurement Canada (PSPC) for the above noted project. We thank you for the opportunity to complete this work on behalf of PSPC. We hope this report meets your current needs. Should you have any questions or require additional information, please do not hesitate to contact the undersigned at (403) 270-9246. Sincerely, AECOM Canada Ltd. Michael Gregg, P.Eng. Air Quality Engineer JL:kw 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Statement of Qualifications and Limitations The attached Report (the “Report”) has been prepared by AECOM Canada Ltd. (“AECOM”) for the benefit of the Client (“Client”) in accordance with the agreement between AECOM and Client, including the scope of work detailed therein (the “Agreement”). The information, data, recommendations and conclusions contained in the Report (collectively, the “Information”): . is subject to the scope, schedule, and other constraints and limitations in the Agreement and the qualifications contained in the Report (the “Limitations”); . represents AECOM’s professional judgement in light of the Limitations and industry standards for the preparation of similar reports; . may be based on information provided to AECOM which has not been independently verified; . has not been updated since the date of issuance of the Report and its accuracy is limited to the time period and circumstances in which it was collected, processed, made or issued; . must be read as a whole and sections thereof should not be read out of such context; . was prepared for the specific purposes described in the Report and the Agreement; and . in the case of subsurface, environmental or geotechnical conditions, may be based on limited testing and on the assumption that such conditions are uniform and not variable either geographically or over time. AECOM shall be entitled to rely upon the accuracy and completeness of information that was provided to it and has no obligation to update such information. AECOM accepts no responsibility for any events or circumstances that may have occurred since the date on which the Report was prepared and, in the case of subsurface, environmental or geotechnical conditions, is not responsible for any variability in such conditions, geographically or over time. AECOM agrees that the Report represents its professional judgement as described above and that the Information has been prepared for the specific purpose and use described in the Report and the Agreement, but AECOM makes no other representations, or any guarantees or warranties whatsoever, whether express or implied, with respect to the Report, the Information or any part thereof. Without in any way limiting the generality of the foregoing, any estimates or opinions regarding probable construction costs or construction schedule provided by AECOM represent AECOM’s professional judgement in light of its experience and the knowledge and information available to it at the time of preparation. Since AECOM has no control over market or economic conditions, prices for construction labour, equipment or materials or bidding procedures, AECOM, its directors, officers and employees are not able to, nor do they, make any representations, warranties or guarantees whatsoever, whether express or implied, with respect to such estimates or opinions, or their variance from actual construction costs or schedules, and accept no responsibility for any loss or damage arising therefrom or in any way related thereto. Persons relying on such estimates or opinions do so at their own risk. Except (1) as agreed to in writing by AECOM and Client; (2) as required by-law; or (3) to the extent used by governmental reviewing agencies for the purpose of obtaining permits or approvals, the Report and the Information may be used and relied upon only by Client. AECOM accepts no responsibility, and denies any liability whatsoever, to parties other than Client who may obtain access to the Report or the Information for any injury, loss or damage suffered by such parties arising from their use of, reliance upon, or decisions or actions based on the Report or any of the Information (“improper use of the Report”), except to the extent those parties have obtained the prior written consent of AECOM to use and rely upon the Report and the Information. Any injury, loss or damages arising from improper use of the Report shall be borne by the party making such use. This Statement of Qualifications and Limitations is attached to and forms part of the Report and any use of the Report is subject to the terms hereof. AECOM: 2015-04-13 © 2009-2015 AECOM Canada Ltd. All Rights Reserved. 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Authors Report Prepared By: Jilayne Lester, EIT Junior Air Quality Engineer in Training Report Prepared By: Pooya Shariaty, PhD, EIT Air Quality Engineer in Training Report Reviewed By: Michael Gregg, P.Eng. Air Quality Engineer 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan List of Abbreviations Abbreviation Full Text AANDC Aboriginal Affairs and Northern Development Canada AAQC Ambient Air Quality Criteria AQMP Air Quality Monitoring Plan AMD Air Monitoring Directive AQC Air Quality Contractor As Arsenic BAM Beta Attenuation Monitor CEPA Canadian Environmental Protection Act CIRNAC Crown-Indigenous Relations and Northern Affairs Canada cfm Cubic Feet per Minute COI Constituents of Interest CC Construction Contractor DAS Data Acquisition System DIAND Department of Indian Affairs and Northern Development Fe Iron GMRP Giant Mine Remediation Project GNWT Government of the Northwest Territories Hi-vol High Volume, High Volume Sampler INAC Indian and Northern Affairs Canada/Indigenous and Northern Affairs Canada NAAQO National Ambient Air Quality Objectives NAPS National Air Pollution Schedule NDL Ndilo Community Air Monitoring Station Ni Nickel NIOSH National Institute for Occupational Safety and Health NO2 Nitrogen Dioxide NVN Niven Community Air Monitoring Station Pb Lead PCM Phase Contrast Microscopy PEI Project Environment Inspector PM10 Particulate matter with a diameter of 10 microns or less PM2.5 Particulate matter with a diameter of 2.5 microns or less PSPC Public Services and Procurement Canada PWGSC Public Works and Government Services Canada QA/QC Quality Assurance/Quality Control Sb Antimony SO2 Sulphur Dioxide TEM Transmission Electron Microscopy TSP Total suspended particulate matter US EPA United Stated Environmental Protection Act VFC Volumetric Flow Controlled YKB Yellowknife Bay Community Air Monitoring Station 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx i AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Summary The Giant Mine site (the Site) is located within the City of Yellowknife boundary, approximately 1.5 kilometres (km) from the community of Ndilǫ and 9 km from the community of Dettah. The Site produced gold from 1948 until 1999 and ore for off-Site processing from 2000 until 2004. In 1999, the owner of the Site went into receivership; care, custody, and control of the Site was transferred to Crown-Indigenous Relations and Northern Affairs Canada (INAC) and the GNWT. Ongoing care and maintenance and the remediation of the Site is known as the Giant Mine Remediation Project (GMRP). An Air Quality Monitoring Plan (AQMP) was developed in 2013 (AECOM 2013a) to provide a description of the air monitoring requirements during the Giant Mine Remediation Project (GMRP). The air monitoring program was reviewed and updated in 2018 based on the information and data collected from 2013-2017 to produce a revised AQMP (this document). This AQMP outlines methods for measuring, documenting, and responding to potential airborne contaminants during the remedial activities. The AQMP is an integrated and tiered air quality monitoring approach starting with activity-specific monitoring on an as-and-when needed basis, moving to the site perimeter (Project boundary) and extending into the communities of Ndilo and Yellowknife. Ambient air quality monitoring at the Giant Mine Site was conducted seasonally from 2005-2012 and as part of the AQMP from 2013-2017 during earthworks, building demolition (including the roaster complex) and general care and maintenance, as per AECOM (2013a) and continued through 2018 and beyond. Results of the monitoring from 2013-2017 were analyzed and used to guide this revision to the AQMP. Analysis of the 2013-2017 data indicated an air monitoring system with excellent data availability from a coordinated network of monitors. The text in this version of the AQMP has been updated to reflect the current air quality monitoring at Site along with updated air quality criteria guidelines but the basis of the air monitoring plan remains the same at this time. The air quality monitoring program for the GMRP consists of three community monitoring stations located in the communities of Yellowknife and Ndilo. These locations were selected based on an analysis of the climatological data (including wind speeds and directions), existing air quality data, location of sensitive receptors and topographic features. The program also consists of nine (9) site perimeter monitoring locations strategically positioned along or near the Project boundary. Activity-specific air quality monitoring is conducted as and when needed on site for higher risk activities. Previous studies served as a reference for the selection of parameters for the monitoring program during remediation. After review of the contaminants that were identified during investigations of the site through historical studies, and following a review of measurements collected from 2013-2017, the target parameters for the air monitoring program were originally identified and remain as arsenic (As), antimony (Sb), asbestos, iron (Fe), lead (Pb), nickel (Ni), total suspended particulates (TSP), particulate matter with a diameter of 10 microns or less (PM10), and particulate matter with a diameter of 2.5 microns or less (PM2.5). The requirements for upper concentration limits for the monitoring program consist of two categories; action levels for the site perimeter (the Project boundary) and the community air quality criteria requirements. The community requirements are based on the ambient air quality criteria (AAQC) set out by appropriate provincial or territorial authorities. The action levels for the site perimeter monitors were established through a risk-based analysis from a site-specific surrogate method that is based on soil concentrations (AECOM 2013 b). These action levels were reviewed in 2018 based on monitoring data from 2013-2017 and were determined to be sufficiently protective. The site perimeter monitoring data is used as a construction and Project management tool to ensure appropriate mitigation measures are implemented. If the action levels for the site perimeter monitoring locations are exceeded, appropriate measures are taken by the parties involved according to the directions outlined in this AQMP and the GMRP Dust Management and Monitoring Plan (DMMP), such as the initiation of an investigation and undertaking of appropriate mitigation steps as necessary. 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx ii AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan The AQMP includes quality assurance and quality control steps specifically focussed on the two aspects of the program (site perimeter and community air quality monitoring) to increase the quality of the measured parameters. Reporting requirements are also outlined in the AQMP and are broken down into real-time reports, and daily, weekly and annual reports. 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx iii AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Table of Contents page 1. AQMP Introduction ...... 1 2. AQMP Objectives ...... 2 3. Project Background...... 3 3.1 Previous Environmental Assessments and Reports ...... 3 3.2 Existing Human Health and Ecological Risk Assessments ...... 4 4. Current AQMP ...... 5 4.1 Overview ...... 5 4.2 Ambient Air Quality Criteria ...... 7 4.3 Sampling Locations ...... 8 5. Site Perimeter Air Quality Monitoring ...... 10 5.1 Target Parameters ...... 10 6. Community Air Quality Monitoring ...... 12 6.1 Community Air Quality Monitoring Sampling ...... 12 6.1.1 Asbestos ...... 12 6.1.2 TSP, PM10, and Inorganic Trace Elements ...... 13 6.1.3 PM10 and PM2.5 ...... 13 6.1.4 Continuous Nitrogen Dioxide (NO2) (Niven Station) ...... 13 6.2 Sampling Duration and Frequency ...... 13 7. Monitoring Type and Frequency ...... 16 8. Air Monitoring Action Levels ...... 18 9. Quality Assurance/Quality Control ...... 25 9.1 Data Collection and Management ...... 25 9.1.1 Data Validation ...... 25 9.1.2 Site Perimeter QA/QC ...... 26 9.1.3 Integrated Sampling Data Handling, Validation and Recovery ...... 26 9.2 Community Station QA/QC ...... 27 9.2.1 Calibrations ...... 27 9.2.2 Integrated Sampling Data Handling, Validation and Recovery ...... 29 9.2.2.1 Laboratory QA/QC ...... 29 9.2.3 Preventative and Corrective Maintenance ...... 29 9.2.4 Equipment Inventory ...... 30 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan 10. Reporting ...... 30 10.1 Real-Time Reports ...... 30 10.2 Daily Reports ...... 31 10.3 Weekly Reports ...... 32 10.4 Weekly Data Reports ...... 33 10.5 Annual Reports ...... 34 11. References ...... 35 List of Tables Table 4-1. Measured Parameters at Site Perimeter and Community Air Monitoring Stations ...... 6 Table 4-2. Air Quality Monitoring Criteria ...... 8 Table 4-3. Site Perimeter and Community Air Monitoring Stations ...... 9 Table 6-1. Community Monitoring – Summary of Air Monitoring Parameters ...... 12 Table 6-2. Site Perimeter and Community Air Quality Monitoring Methodology, Specifications, and Frequency .... 14 Table 7-1. Air Quality Monitoring Levels ...... 18 Table 8-1. Site Perimeter Air Monitoring Action Levels – Visible Dust ...... 20 Table 8-2. Site Perimeter Air Monitoring Action Levels – PM10 ...... 21 Table 8-3. Site Perimeter Air Monitoring Action Levels – TSP ...... 23 Table 10-1. Summary of Real-Time Site Perimeter Monitoring Data ...... 31 Table 10-2. Summary of 24-Hour Average Continuous Concentrations ...... 31 Table 10-3. Summary of Activity-Specific Monitoring Data ...... 32 Table 10-4. Summary of Daily NO2 Concentrations at Niven Lake Community Station ...... 33 Appendices Appendix A. AQMP Monitoring Locations Appendix B. Action Level Derivation Memo Appendix C. Analysis of 2013-2017 Monitoring Data Appendix D. Historical Ambient Air Monitoring Appendix E. Monitoring Requirements Decision Tree 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan 1. AQMP Introduction The Giant Mine (the Site) is located within the municipal boundary of Yellowknife in the Northwest Territories, approximately five kilometres north of the city centre; Figure 1 shows the location of the Site. The historic operation of Giant Mine resulted in widespread contamination of surface and subsurface soils. On-site ore processing generated arsenic trioxide dust which was discharged to the atmosphere in early years of mine operation and subsequently deposited on surface soils. A large portion of this by-product was collected and is stored in fourteen purpose-built chambers and mined-out stopes underground. Additionally, there are four tailings containment areas on Site which contain a less-toxic speciation of arsenic (As(V)) as well as other trace metals. The Giant Mine Remediation Project (GMRP) is intended to stabilize contaminated materials during remediation, however, some activities associated with the GMRP have the potential to generate dust which can be entrained in the ambient air either from the activity itself or assisted by unfavourable meteorological conditions. Mitigation measures are incorporated into remedial activities and management plans to substantially reduce the possibility of fugitive emissions from those activities. An Air Quality Monitoring Plan (AQMP) was developed in 2013 (AECOM 2013) and revised in 2018 (this document) following a review of ambient air quality measurements collected from 2013-2017. The AQMP provides a description of the air monitoring requirements during the GMRP and outlines methods for measuring, documenting, and responding to potential airborne contaminants during the remedial activities. It will be updated on a regular basis upon review of recommendations in annual air quality monitoring reports. The framework used to design the remedial phase AQMP includes the following basic steps: . Define program goals; . Specify target parameters; . Specify number and location of monitoring sites; . Specify duration and frequency of monitoring; . Specify monitoring methods; . Specify data quality objectives; . Specify Quality Assurance/Quality Control (QA/QC) program; . Specify data management and reporting systems; and . Specify compliance criteria and site action levels. The AQMP consists of a community air quality monitoring component and a site perimeter air quality monitoring component. Activity-specific air quality monitoring is conducted as and when needed for higher risk activities such as the completed roaster complex demolition or major earthworks in heavily contaminated areas. Appendix A shows the location of the site perimeter and community air monitoring stations; activity-specific monitors are not shown on the figure as their use and location are variable and depend on the location of a given activity. Occupational health monitoring is also conducted on Site as required dependent on specific activities; this monitoring is not covered in the AQMP. 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 1 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan 2. AQMP Objectives The objective of the AQMP is to help protect the environment, workers on-site and the public from health impacts as a result of remediation activities. The main goals of the air monitoring program are: 1. To measure air quality in the vicinity of remediation emissions to ensure overall compliance with established criteria. Real-time concentration averages will be continuously monitored on-site during remedial activity and the values will be compared to approved short-term action levels to assist site managers in assessing or modifying site activities to prevent exceedances of project criteria. 2. To measure ambient air quality in the community surrounding the remediation sites to confirm that there are no significant impacts to community air quality as a result of remediation activity. To achieve Objective 1, site perimeter air quality monitoring provides the basis for assessing real-time air quality conditions at the Site and consists of continuously calculated 15-minute average concentrations of Total Suspended Particulate (TSP) and Particulate Matter of 10 microns or less (PM10) at nine locations at or around the Project boundary to monitor effects from remedial activities on the local ambient air quality. It also consists of integrated filter-based samples for 24-hour average concentrations of PM10 and TSP. The site perimeter monitors are operated seasonally during non-snow covered months (typically May to November inclusive) or in response to activities on the Site during winter months. If a concentration above the established Risk-Based Action Level (RBAL) for PM10 or TSP (see Section 4.2 and Appendix B for more details) is measured at any of the nine perimeter locations, an automatic notification is sent by email to the Air Quality Contractor (AQC) personnel and they are required to notify the Main Construction Manager immediately investigate any on-site activities or equipment failure to identify potential causes and determine if mitigation measures are required. Site perimeter monitoring also consists of integrated filter-based 24-hour average concentrations of PM10 and TSP and trace metals. Site perimeter monitoring is discussed in Section 5. Additionally, activity-specific monitoring is conducted for higher risk activities which have the potential to create significant dust and/or are located in more heavily contaminated areas such as tailings containment areas. These monitors are generally triangulated around the specific activities. These monitors act as an early detection system to help to identify PM10 concentrations above baseline of particulates adjacent to a work area so that mitigation measures can be put into place before exceedances are measured at the site perimeter. To achieve Objective 2, three community air monitoring stations are operated off-Site as part of the AQMP. Two are located within the City of Yellowknife and the third in the community of Ndilo. The community stations monitor PM2.5 and PM10 on a continuous basis, recorded hourly. The three stations also collect discrete 24-hour filter samples that are analyzed for TSP gravimetrically and then post-exposure for selected trace metals: antimony (Sb), arsenic (As), iron (Fe), lead (Pb), and nickel (Ni) as well as 24-hour filter samples analyzed for PM10 gravimetrically and then post-exposure for arsenic in accordance with the National Air Pollution Surveillance (NAPS) schedule. Twenty-four hour integrated samples for asbestos are also collected at all three community stations. Continuous nitrogen dioxide measurements recorded hourly occur at the Niven community air monitoring station. The community monitoring stations currently operate continuously throughout the year. Community monitoring is discussed in Section 6. In addition to these monitoring stations, one additional community monitoring station is operated in the City of Yellowknife by the Government of the Northwest Territories (GNWT). While no longer part of the GMRP AQMP, data from this station is periodically used for comparison and information purposes with the data collected under the AQMP. 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 2 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan 3. Project Background The Giant Mine Site is located within the city of Yellowknife boundary, approximately 1.5 km from the community of Ndilo and 9 km from the community of Dettah. The Site is situated on Commissioner’s Land administered by the Government of the Northwest Territories (GNWT). A Reserve (R622T) has been established to allow for the implementation of the remediation of the Site. Subsurface mineral rights are under federal jurisdiction and were withdrawn by Order in Council SI/2005-55 on 15 June 2005. The Site produced gold from 1948 until 1999 and ore for off-site processing from 2000 until 2004. In 1999, the owner of the Site went into receivership; care, custody, and control of the site was transferred to Crown-Indigenous Relations and Northern Affairs Canada (CIRNAC) and the GNWT. Ongoing care, maintenance and remediation of the Site is known as the Giant Mine Remediation Project (GMRP). The historic mining process created a by-product of arsenic trioxide dust, of which approximately 237,000 tonnes is currently stored in fifteen underground chambers and mined out stopes. The Giant Mine Remediation Project (GMRP) is intended to stabilize contaminated materials, however, some activities associated with the GMRP have the potential to generate dust which can be entrained in the ambient air either from the activity itself or assisted by unfavourable meteorological conditions. Mitigation measures are incorporated into remedial activities in order to substantially reduce the possibility of fugitive emissions from those activities. The objective of the AQMP is to maintain a robust and protective air monitoring program that provides data that will be used to help prevent potential adverse effects to the environment and human health from airborne contaminants during the remediation activities. 3.1 Previous Environmental Assessments and Reports The Giant Mine Environmental Assessment (EA) began in 2008 under the jurisdiction of the Mackenzie Valley Environmental Impact Review Board and was completed in 2014. The atmospheric environment (air quality) was identified in the EA and in the Developer’s Assessment Report (DAR) (INAC and GNWT, 2010) as an environmental component that was and could be affected by past, present or future activities. The overall long-term goal of the Remediation Project is to prevent adverse effects that would result if no action was taken. Though the future effects of the project will benefit the environment and improve the current situation, site remediation activities may result in residual effects, notwithstanding extensive mitigation measures. In 2013 AECOM developed the Air Quality Monitoring Plan (AECOM, 2013) to measure effects of the onsite activities on ambient air quality that may not be controlled by the mitigation measures. The monitoring program has collected a wealth of air quality information since 2013 from the locations along the site perimeter and in the communities of Yellowknife and Ndilo. Some of the known and potential residual effects summarized in the DAR and the GMRP Closure and Reclamation Plan (GMRP, 2019) include: . Increase in suspended solids (dust) during earthmoving activities; . Combustion emissions from equipment and vehicles during on-site activities; . Release of existing contaminants to air during remediation of contaminated areas; . Surface disturbances affecting terrestrial habitat and biota; and 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 3 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan . Asbestos containing material in the site buildings, identified as a hazard for building deconstruction. Based on the evaluation of the residual effects on the atmospheric criteria in the DAR (2010), it was concluded that with the proposed mitigation measures in place, residual adverse effects will be minor since most of the residual effects will be temporary and restricted to the remediation phase. A screening level air dispersion modelling assessment was completed with the use of the United States Environmental Protection Agency’s (USEPA) Industrial Source Complex Short-Term (ISCST3) modelling software (Giant Mine Remediation Project, 2010). The screening level modelling assessment identified the following as Constituents of Interest (COI): Total Suspended Particulates (TSP), Particulate Matter with a diameter of 10 microns or less (PM10), Particulate Matter with a diameter of 2.5 microns or less (PM2.5), NO2 and SO2. The conclusion was that combustion emissions (NO2 and SO2) would exceed applicable 1-hour criteria in the immediate vicinity of heavy equipment operations. The primary source of particulate emissions was windblown dust. The offsite receptors were predicted to be within the allowable criteria for both particulates and combustion emissions. The mitigation measures to be implemented for emissions from vehicles and bulldozing activities were watering and the application of calcium chloride to reduce evaporative loss (Giant Mine Remediation Project, 2010), (SENES,2012). Refined air quality assessments using CALMET/CALPUFF were contracted in 2012 by CIRNAC to complete air contaminant dispersion analysis. The dispersion model evaluated Giant Mine remediation activities and assessed particulate emissions (TSP, PM10, and PM2.5) and combustion emissions (NO2 and SO2). Projected worst case operations of the Jackfish Power Plant were also included in the assessment, with the idea that an active freeze system would be built on site. (This is no longer the case, with a passive freeze system now planned.) The results of the screening level assessment were consistent with the CALPUFF results, in that with reasonable mitigation during remediation activities, wind-blown dust would be the primary emission source of TSP and arsenic (SENES, 2012). However, the CALPUFF results predicted exceedances of on-site and off-site receptors. The minimum conservative assumption (power plant operating continuously at 18 MW) had a predicted exceedance of 1-hour NO2 and 24-hour PM2.5 at one receptor location. The worst case maximum operation scenario for short term (power plant operating continuously at 27 MW for 1-hour) predicted significant exceedances of 1-hour NO2 emissions at two off-site receptor locations closest to the plant. On-site receptor locations were predicted to have exceedances of applicable criteria. The results also show that based on the operation of the freeze plant with 3 megawatts of incremental power from the Jackfish Power Plant, there would be no resultant NO2 and SO2 exceedances of applicable criteria at the sensitive receptor locations (SENES, 2012). 3.2 Existing Human Health and Ecological Risk Assessments Four risk assessments have been completed for the Giant Mine Site. In 2001-2002, an ecological and human health risk assessment was completed to assess the evaluation of alternative scenarios for the management of underground arsenic trioxide dust. In 2003 a screening level risk assessment for the site was completed. Following the screening level risk assessment, a Tier 2 Risk assessment was completed for the surface remedial activities in 2006 (SENES, 2006). A Human Health and Ecological Risk Assessment was also completed by the GMRP in 2016/17 (CanNorth, 2018). Risk assessments were carried out in support of assessing the potential adverse effects on human health, aquatic and terrestrial species in the vicinity of the site. The 2003 screening level risk assessment examined existing conditions at the Giant Mine site and used conservative assumption and literature transfer factors to assess effects from the surface conditions at the site. The 2003 results indicated that in addition to arsenic; antimony (Sb), lead (Pb) and nickel (Ni) also present risks to humans due to existing surface conditions at the site. Subsequent reviews 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 4 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan of the 2003 findings resulted in hazard quotient values below 0.5 for Pb and Ni. Therefore, Pb and Ni were not found to be COIs at the site. The primary source of Sb was found to be contaminated soils and that the proposed Remediation Plan of arsenic-contaminated soils will also lead to a substantial reduction in the Sb levels in the soils left on surface at the site. (SENES, 2006). A human health risk assessment was completed to determine the different levels of impacts on human receptors. The major pathways of exposure to background levels of arsenic were in the ingestion of water and food; air and soil inhalation pathways were considered insignificant contributors to overall arsenic exposure by Environment Canada (Environment Canada, 1993). As outlined in the previous risk assessment, toxic arsenic has carcinogenic effects, and carcinogenic risk is evaluated by the incremental incidence of developing cancer in a lifetime of exposure. In the assessment study, the predicted cancer risk for the remediation study was 6.1 in 10,000. This is well below the lifetime incidence cancer rate of 3 in 10 for the Northwest Territories population. Based on these statistics, the risk of developing cancer from total arsenic exposure is up to 300 times lower than the overall cancer risk for the population. However, while the incremental lifetime risk levels are above the acceptable level of 1 in 100,000 from Health Canada, the predicted levels of cancer development from exposure to arsenic releases from the site will not be distinguishable to the current levels of cancer development in the Yellowknife population (SENES, 2006). Overall, the human health risk assessment calculations found that arsenic intake by humans will be maintained within the estimated range for other Canadians and hence would have little risk of adverse health effects. Previous reports outlined the requirement for restrictions on future activity at the site until site monitoring programs prove that arsenic levels are within safe limits (Giant Mine Remediation Project, 2010). 4. Current AQMP 4.1 Overview The overall commitment of the GMRP is to ensure that appropriate measures and precautions are taken for the GMRP to occur successfully in a manner that is protective of the environment and human health. The AQMP is one measure that the GMRP implements to protect the local air quality during remediation activities. Past air quality monitoring from 2005 to 2012 show that there were some recorded exceedances from dispersion modeling and air monitoring for TSP, PM10, As, Fe, NO2 and SO2. Significant dust mitigation measures on-site, including the annual application of dust suppressant on the TCAs, has greatly reduced the amount of visible dust on Site and the number of exceedances at Site monitoring stations. Monitoring results from 2013–2017 AQMP data show that overall the site perimeter and community stations have excellent data availability. The stations for these two program components responded similarly to large-scale events such as elevated particulate concentrations associated with wildfires over the monitoring period, and correlations between elevated readings between stations occur frequently, indicating that the system is functioning well as a coordinated network. Outside of wildfire events there were very few exceedances of the RBAL on site perimeter stations and no exceedances of the RBAL on the community stations. There were no exceedances of the air quality criteria for arsenic at any of the site perimeter or community stations during the 2013 – 2017 monitoring period. (AECOM, 2018) 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 5 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan The air quality monitoring program includes three community monitoring stations located in the communities of Yellowknife (2 stations) and Ndilo (1 station). These locations were previously selected based on an analysis of the climatological data (including wind speeds and directions), existing air quality data, location of sensitive receptors and topographic features. The program also includes nine site perimeter locations at or near the Project boundary. Activity-specific monitors are used as and when needed based on Project activities. Previous studies served as a reference for the selection of parameters for the monitoring program during remediation. After review of the contaminants that were identified during investigations of the site through historical studies, and following a review of measurements collected from 2013-2017, the target parameters for the air monitoring program were identified and remain as arsenic (As), antimony (Sb), asbestos (Community stations only), iron (Fe), lead (Pb), nickel (Ni), total suspended particulates (TSP), particulate matter with a diameter of 10 microns or less (PM10), and particulate matter with a diameter of 2.5 microns or less (PM2.5) (PM2.5 at community stations only). The above parameters are laid out in Table 4-1 as well. Table 4-1. Measured Parameters at Site Perimeter and Community Air Monitoring Stations Station Description AQMP Measured Parameters Continuous basis reported as 15-minute averages: . TSP, PM10 Site Perimeter Stations Discrete 24-hour samples: . TSP plus Sb, Fe, Pb, Ni . PM10 plus As Continuous basis recorded hourly, reported as 24-hour averages: . PM10, PM2.5 . NO2 (Niven station only) Community Stations Discrete 24-hour samples: . TSP plus Sb, Fe, Pb, Ni . PM10 plus As . Asbestos The requirements for upper concentration limits for the monitoring program consist of two categories; action levels for the site perimeter (the Project boundary) and the community requirements. The community requirements are based on the ambient air quality criteria (AAQC) set out by appropriate provincial or territorial authority. The action levels for the site perimeter monitors were established through a risk-based analysis from a site-specific surrogate method that is based on the soil concentrations (AECOM 2013b) Appendix B and were reviewed in 2018 against air quality monitoring data collected between 2013-2017. The site perimeter monitoring data is used as a construction and project management tool to ensure appropriate mitigation measures are implemented. If the action levels for the site perimeter monitoring programs are exceeded, appropriate measures are taken by the parties involved according to the directions outlined in this air monitoring plan, such as the initiation of an investigation or the appropriate mitigation steps. See Section 8. In addition to the air monitoring devices, meteorological conditions are observed. Meteorological data such as wind speed, wind direction, humidity and precipitation can have a significant effect on fate and transport of atmospheric emissions from the Project. An onsite meteorological station is used as the point of reference for obtaining ongoing meteorological parameters in 15-minute increments. Meteorological data in 15-minute increments is used to appropriately assess the potential source location for potential exceedances of the 15-minute action level. Onsite meteorological data is also used to gauge the direction of emission plumes from their source. Meteorological information can be found in Appendix C. 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 6 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan The AQC collects real-time weather data including wind direction, speed, temperature, precipitation and relative humidity from the onsite station. The AQC also obtains detailed 24-hour weather forecasts prior to each work day from Meteorological Services Canada and communicates relevant details such as forecasted high winds to the Main Construction Manager (MCM) and/or relevant parties. The AQMP includes quality assurance and quality control steps specifically focussed on the two aspects of the program (site perimeter and community air quality monitoring) to increase the quality of the measured parameters. Reporting requirements are also outlined in the AQMP and are broken down in to real time reports, and daily, weekly and annual reports. The AQC is responsible for operating and maintaining the community air monitoring equipment, providing and maintaining site perimeter air monitoring equipment, as well as sample collection, transportation, subcontracting a laboratory for analyses of samples, data validation, QA/QC, interpretation, reporting and management of monitoring results. 4.2 Ambient Air Quality Criteria Ambient air quality criteria have been established to evaluate air monitoring results and to help protect local air quality. The GNWT Department of Environment and Natural Resources has developed a Guideline for Ambient Air Quality Standards based on the National Ambient Air Quality Objectives (NAAQO’s) and Canada Wide Standards (CWS). This guideline was established under the GNWT’s Environmental Protection Act and sets the standards for ambient air quality throughout the Northwest Territories (GNWT, 2014). In cases where there is no applicable GNWT standard, air monitoring results are compared to the Ontario Ambient Air Quality Criteria (Ontario Ministry of Environment, April 2012). In addition, the Health Canada Unit Risk factor was used to derive the community annual criteria for arsenic. The arsenic criterion is outlined in the Health Canada publication, “Federal Contaminated Site Risk Assessment in Canada. Part II: Health Canada Toxicological Reference Values” (Health Canada, 2004). The risk-based community air quality arsenic criterion was calculated considering the following: . Health Canada’s arsenic risk factor; . Incremental lifetime cancer risk screening; and . A ten-year work plan exposure. Using the Health Canada Unit Risk factor for arsenic of 0.0064 (µg/m3)-1 (Health Canada 2004), which corresponds to 70 years of exposure, the air quality concentration for arsenic corresponding to the Giant Mine site remediation, were it to last as long as ten years, is 0.011 µg/m3 [(1 x 10-5 / 0.0064 (µg/m3)-1) x (70 yr / 10 yr)] (AECOM, 2013). For arsenic, consideration of carcinogenic effects for annual criteria results in more stringent annual criteria than when considering non-carcinogenic effects. For further information regarding the use of Health Canada Toxicological Reference Values for the development of project specific arsenic criteria, please refer to AECOM’s letter dated April 12, 2013 regarding “Real-time Fenceline Monitoring Risk-Based Action Level (RBAL) for PM10” (AECOM, 2013 b) (Appendix B). Any exceedances to the air quality criteria at any site perimeter or community air monitoring station are immediately investigated, reviewed and acted upon as appropriate. The MCM determines the appropriate short-term action required with subcontractors, using approved methods and dust suppressants. If concentrations exceed the criteria, an evaluation of both remedial procedures and control measures is warranted. If exceedances are determined to be project related, corrective measures will be identified by the MCM in association with all applicable parties. Long- term trends will be compared against relevant annual criteria and will be used as a benchmark to measure effects associated with the remediation project (Section 8). 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 7 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Table 4-2 summarizes the relevant air quality criteria for the GMRP. Table 4-2. Air Quality Monitoring Criteria Averaging Source Parameter AAQC (µg/m3) Period (Current as of 2018) Guideline for Ambient Air Quality Standards in the 24-hour 120 TSP Northwest Territories (February, 2014) 3 (µg/m ) Guideline for Ambient Air Quality Standards in the Annual 60 Northwest Territories (February, 2014) PM10 Ontario Ambient Air Quality Criteria 24-hour 50 (µg/m3) (April, 2012) Guideline for Ambient Air Quality Standards in the PM2.5 24-hour 28 Northwest Territories (February, 2014) 3 Guideline for Ambient Air Quality Standards in the (µg/m ) Annual 10 Northwest Territories (February, 2014) NO2 Guideline for Ambient Air Quality Standards in the 24-hour 200 (µg/m3) Northwest Territories (February, 2014) SO2 Guideline for Ambient Air Quality Standards in the 24-hour 150 (µg/m3) Northwest Territories (February, 2014) Annual Health Canada Toxicological Reference Valuesa (2004) 0.011 As 3 Ontario Ambient Air Quality Criteria (µg/m ) 24-hour 0.3 (April, 2012) Fe Ontario Ambient Air Quality Criteria 24-hour 25 (µg/m3) (April, 2012) Ontario Ambient Air Quality Criteria Ni 24-hour 0.2 (Ni in TSP) (April, 2012) Ontario Ambient Air Quality Criteria Pb 24-hour 0.5 (April, 2012) Ontario Ambient Air Quality Criteria Sb 24-hour 25 (April, 2012) Asbestos 24-hour Ontario Ambient Air Quality Criteria (April, 2012) 0.04 (fibres/cm3) Site Perimeter - TSP Risk Based Action Levelb 15-minute - 333 Site Perimeter - PM10 Risk Based Action Levelb 15-minute - 159 a Derivation calculated using Health Canada’s Toxicological Reference Values in “Real-time Site Perimeter Monitoring Risk-Based Action Level (RBAL) for PM10” (AECOM, 2013) b Derived from toxicological references for the hypothetical on-site worker/trespasser, chronic criterion based on protection against both an incremental carcinogenic risk of 1 x 10-5 (Health Canada, 2004) using the Health Canada Inhalation Unit Risk Factor. 4.3 Sampling Locations To determine the siting of the community air monitoring stations, several factors were reviewed and analyzed. (See Location Plan map in Appendix A for station locations). Factors that were taken into consideration in establishing the monitoring locations included: . The review of existing ambient air quality data within the study area; using historical ambient air quality data; 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 8 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan . The location of project activities and sensitive receptors such as residential dwellings, health care facilities and education facilities; . The variability of local wind patterns by reviewing meteorological data from the site-specific monitoring collected by CIRNAC and the Yellowknife Airport meteorological data. Meteorological data was analyzed for the period 2013-2017 with seasonal wind roses and frequency distributions for both the on Site meteorological station and the Yellowknife Airport presented in Appendix C; and . The location of topographic features that affect the dispersion of emissions. Based on these factors, monitoring sites were chosen that will be representative of the general group of sensitive receptors within the study area. To achieve the goals for this AQMP, three (3) air monitoring locations were selected based on the meteorological data for wind directions, the location of receptors and the location of the remedial activities. The first station is the Yellowknife Bay Community Station (YKB, previously named YCC), is located in the Marina closest to the Project Site. The second station (NDL) is located south of the Site on Latham Island in the Yellowknives Dene First Nations community of Ndilo. The third station is located in the Niven Lake area (NVN). During the review of 2013-2017 air quality monitoring data, the spatial distribution of station locations for the site perimeter air quality monitoring stations were also reviewed. It was determined that the stations correspond similarly to large-scale events such as forest fires, as well as to local events at the site perimeter indicating the air monitoring network functions as a coordinated network. In addition, there is an existing NAPS station in Yellowknife run by the GNWT which is not part of the AQMP. Data is retrieved and reviewed, and used for comparison purposes with the three community stations of the AQMP. Please refer to Appendix A for the monitoring locations mentioned. There are nine site perimeter monitoring stations at the Project boundary as part of the site perimeter monitoring program. These locations were selected after considering the proposed work locations, public access, wind speeds, direction, frequency and the general layout of the site. Six of the site perimeter monitoring stations have been monitoring since 2013, and three more stations were installed in 2016. A review of the 2013-2017 data produced a recommendation to remove one site perimeter monitoring stations as possibly redundant, however that recommendation has not been implemented for this AQMP. (See Table 4-3 below and Appendix A for station locations.) Table 4-3. Site Perimeter and Community Air Monitoring Stations Station ID Station Description Station Location A-North Site perimeter Station A 62.51131,-114.33185 B-Town Site perimeter Station B 62.49022,-114.35873 C-Northwest Site perimeter Station C 62.5229,-114.34926 D-Beach Site perimeter Station D 62.49748,-114.34496 E-A1C1 Site perimeter Station E 62.49459,-114.36899 F-Marina Site perimeter Station F 62.48592,-114.36093 G-West Site perimeter Station G 62.50639,-114.365 H-Northwest Pond Site perimeter Station H 62.51944,-114.3625 I-South Pond Site perimeter Station I 62.49994,-114.34744 NDL Ndilo Community Station 62.47562,-114.33795 YKB* Yellowknife Bay Community Station 62.48593,-114.36094 NVN Niven Community Station 62.46509,-114.37318 *Note: The air quality monitoring station at the Great Slave Sailing Club (YKB) was formerly (erroneously) named YCC. 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 9 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan 5. Site Perimeter Air Quality Monitoring The site perimeter air monitoring component of the AQMP is critical to ensure that the remediation work is carried out in a manner that mitigates atmospheric emissions. The site perimeter stations correspond wherever practical with the Project boundary. The primary objective of the site perimeter air monitoring program is to measure air quality on a continuous basis and record 15-minute average concentrations of PM10 and TSP. Real-time monitoring data are compared to established short-term action levels or Risk-Based Action Levels (RBALs) developed to assist construction managers to respond and modify site activities, as appropriate, to prevent associated exceedances of 24-hour ambient air quality criteria at community monitoring stations located in Ndilo and/or Yellowknife. This is accomplished by comparing real-time site perimeter data collected to developed site action levels on an hourly basis. Site perimeter air monitoring also consists of 24-hour integrated filter-based samples for PM10 and TSP, as well as trace metals (antimony, arsenic, lead, nickel, and iron) and arsenic. Site perimeter air monitoring occurs seasonally during non-snow covered months or when warranted by on-site remediation activities. At the site perimeter stations, TSP and PM10 are currently (as of 2018) measured using separate MetOne E- Samplers. In 2017 these monitors replaced the TSI DustTrak monitors that were used at the beginning of the monitoring program due to better performance in cold weather as well as due to filter analysis capabilities of the MetOne E-Samplers. 5.1 Target Parameters The real-time air quality work will focus available resources on those COI’s that have been determined to pose the most significant health risks during remedial activity. The real-time program identifies target compounds that can be monitored effectively on-site on a continuous basis using portable equipment, which are: PM10, TSP, and 24- hour integrated filter samples of PM10 gravimetric and arsenic and TSP gravimetric and trace metals (antimony, arsenic, lead, nickel, and iron). The target compounds have been selected based on the following: . Toxicity or unit risk factor of the particular COI; . Relative concentration of the COI present in the buried waste or soil; . The COI’s rate at which the compound is emitted to the air; . The location and spatial coverage of the remedial activities; . Limitations and effectiveness of real-time monitoring equipment in measuring the types of air emissions typically released to the air by these activities; and . Analysis of 2013-2017 monitoring results. Rapid data turnaround is an important consideration in the selection of real-time monitoring equipment. Turnaround times are critical when the monitoring data are being compared with short-term action levels during remediation. A multi-level approach to real-time monitoring had been developed which includes: . Visual (dust) by sensory detection; . Continuous reading particulate monitors at perimeters and near source(s), recorded in 15-minute average concentrations. 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 10 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Any remediation activity that moves or disturbs soil or waste at the site can potentially result in air emissions of COIs and particulate matter (i.e., dust). Solid or liquid particles can be released from remedial activity into the ambient air, including contaminated soil particles and inorganic trace elements. Control of particulate emissions at the remediation source will limit concentrations of inorganic elements (as particulate-borne concentrations) in the ambient air surrounding the site. In addition, the wind direction, wind speed, humidity and precipitation will be important meteorological parameters that will be monitored during remedial activities. These meteorological parameters are chosen to be monitored for the following reasons: . These parameters may affect the fate and transport of airborne emissions . Wind direction and speed will be important to assess location of the monitoring locations in relation to downwind receptors and on-site activities . Humidity and precipitation events may impact the results of the monitors In summary, the target parameters include the following: . Visible dust plumes from on-site activity – monitoring the source of plume and the direction headed . TSP site perimeter monitoring locations . PM10 site perimeter monitoring locations . Trace metals: antimony, lead, nickel, and iron . Arsenic . Wind direction, wind speed, humidity and precipitation will be monitored at the on-site meteorological station Site Perimeter monitoring will be conducted to measure air quality in real-time and used to implement operational controls to reduce the potential for fugitive dust emissions to emanate from the site, as needed. Therefore, the instrumentation selected for the site perimeter program will be portable and have the ability to provide quick/real- time results. Air quality monitoring is currently conducted at site perimeter locations using Met One E-Sampler aerosol monitors, equipped with either PM10 or TSP sampling cyclones, that continuously measure and record 15-minute average concentrations of PM10 or TSP. The 15-minute average particulate matter concentrations are transmitted to an off- site alert system computer that tracks and compares concentration data with previously derived Risk-Based Action Levels (RBALs). The monitor at each site is set up in a weather resistant environmental enclosure that sits on a tripod for continuous monitoring and operates on battery and/or solar power. The environmental enclosure protects the monitor from the elements and includes a sample inlet tube and pump for active air sampling. The AQC is responsible for maintaining an ongoing real-time log of concentrations for each 15-minute averaging period. The concentrations will be continuously compared to the Action Levels defined in Section 8. To summarize, a valid hourly monitoring database at the site perimeter will require, as a minimum, the following: . A frequency of three (3) 15-minute valid readings per hour at each downwind location will be required; . One (1) upwind 15-minute reading for every 1-hour period will be required and used to compare the downwind values for the same hour, and; 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 11 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan . The fixed stations will continuously monitor 15-minute readings (i.e. three (3) 15-minute readings per hour will occur at the fixed stations). 6. Community Air Quality Monitoring As previously noted, the community air quality monitoring component of the AQMP consists of three air monitoring stations that operate year-round, collecting continuous and discrete integrated ambient air quality samples. Table 6-1 summarizes the monitoring parameters for each community monitoring station. Table 6-1. Community Monitoring – Summary of Air Monitoring Parameters YKB NDL NVN Yellowknife Bay Marina Ndilo Community Niven Community Asbestos as fibres > 5 um in length As Sb Fe Pb Ni (in TSP) TSP PM10 PM2.5 NO2 Daily and annual concentration data is compared to the ambient air monitoring criteria for the appropriate time periods (Table 4-2) to monitor overall airshed quality during each phase of the remediation work. Any upward trends in average concentration for an individual or group of contaminants will be identified and evaluated in terms of project impact. In the event that these upward trends are determined to be project related, an evaluation of remedial procedures will be warranted (see Air Monitoring Action Levels in Section 8). 6.1 Community Air Quality Monitoring Sampling 6.1.1 Asbestos Twenty-four hour average sampling for asbestos is currently conducted using SKC Flite 2 sampling pumps. The sampling pumps are programed to sample at a rate of approximately 5 litres per minute (L/min). A BGI BIOS DryCal flow standard is used before and after each sample collection period to verify the sample rate and calculate the average sampling flow rate. Asbestos fibres are collected on a 47-millimetre mixed cellulose ester (MCE) filter media and post-exposure filters submitted to a certified laboratory for asbestos analysis in accordance with NIOSH method 7400. Chain of custodies submitted with the asbestos samples documented sample start and stop times, pre and post sampling flow rates, average sampling flow rates, and sample volume. Results are provided in concentration units of counts of fibres of asbestos per cubic metre of air sampled. 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 12 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan 6.1.2 TSP, PM10, and Inorganic Trace Elements TSP and PM10 is collected with High-Volume (Hi-Vol) samplers in accordance with the US EPA methods and the Canadian standards. The samples will be submitted for gravimetric analysis and for subsequent analysis for Sb, As, Fe, Pb and Ni (EPA Reference Document 40CRF Part 50 Appendix B). The Hi-Vol sampler that is used for this sampling program will be a Volumetric Flow Controlled (VFC) type, equipped with a vacuum motor (pulling air through an 8”x10” filter supported by a wire mesh). The selection of a Tisch Environmental Hi-Vol sampler (or equivalent Hi-Vol sampler) is based on the operating specifications and research on the climate indicating that it would stand up to the conditions. Historical air monitoring in the region has also used similar methods and as such will have results that can be compared to this monitoring program for an analysis of environmental effect trends. The use of the Hi-Vol samplers will help to ensure data consistency throughout the remediation program. The sample-inlet collection efficiency also meets the EPA Code of Federal Regulations (Appendix B, Part 50). The range of operation specifications meets the project needs for this AQMP. Mechanical timers (instead of LCD) can also be implemented with these instruments to stand up to more extreme cold weather application (Tisch, 2013). Additionally, the operation in the application of the baseline study will ensure that the data is consistent throughout the remediation. The Hi-Vol samplers with their volumetric flow control is recommended by the EPA for measuring air quality standards since automatically maintaining constant flow during sampling periods reduces errors due to the method for calculating the particle concentration (weight per sampling flow rate) and the Tisch models use a continuous flow recorder (Tisch, 2013) (EPA Reference Document 40CRF Part 50 Appendix B). 6.1.3 PM10 and PM2.5 PM10 and PM2.5 are continuously measured at the stations using separate Beta Attenuation Monitors (BAM) monitors. The BAM-1020 is controlled by an advanced microprocessor system that makes it fully automatic. The BAM devices use the continuous tape method to detect airborne particles. At the beginning of the sampling period, beta ray transmission is measured across a clean section of filter tape. This section of filter tape is then mechanically advanced to the sampling inlet. Particulate matter is then drawn into the sample inlet and deposited on the filter paper. At the completion of the sampling period, the filter tape is returned to its original location and the beta ray transmission is re-measured. The difference between the two measurements is used to determine, with exceptional accuracy, the particulate concentration. The mass density is measured using the technique of beta attenuation. A small 14C beta source (60 μCi) is coupled to a sensitive detector that counts the emitted beta particles. The samplers provide hourly averages of particulate concentrations in micrograms per cubic meter. A real-time data telemetry system, which has the capability of telemetering the collected data via satellite to a central computer, is employed. Data is ultimately be archived and stored in a central computerized database. 6.1.4 Continuous Nitrogen Dioxide (NO2) (Niven Station) Ambient air monitoring for NO2 is conducted at the NVN community station using a Teledyne T200 monitor. Monitoring of NO2 is measured on a continuous basis and recorded hourly. 6.2 Sampling Duration and Frequency Wind speed and wind direction will be continuously monitored and logged in 15-minute increments. Precipitation and humidity will be continuously monitored and logged on an hourly basis, as a minimum. Wind speed, wind 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 13 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan direction, precipitation and humidity will be obtained on an ongoing basis from the on-site meteorological station, as well as the meteorological station at the Yellowknife Airport. Continuous monitoring for PM10 and PM2.5 (i.e. automated and continuously monitoring and logging data 24/7 and can be used to assess effects in real time if desired) is conducted at all three community stations year-round according to the National Air Pollution Surveillance (NAPS) program schedule. Continuous monitoring for PM10 and TSP is conducted at the site perimeter stations when in operation. PM10 is the parameter that is used as a project management tool to help determine the appropriate mitigation measures. Therefore, it is important that PM10 is continuously monitored at both the site perimeter and the community air quality monitoring locations (Appendix A). PM2.5 is monitored to validate data from past environmental assessments and studies. Once enough data has been collected for validation, this parameter may no longer be monitored. TSP, PM10, As, Sb, Fe, Pb and Ni is monitored every three (3) days over 24 hours during the period in which the site perimeter air monitoring stations are also operating. The frequency of monitoring these parameters is reduced to once every six days during the period when the site perimeter air monitoring stations are not in operation. These targeted parameters require filters to be collected and shipped to a qualified laboratory for further analysis. During periods of remedial activity air sampling is performed every three days over an automated 24-hour period (12AM to 12AM) in accordance with Environment and Climate Change Canada’s NAPS cycle for sampling that requires integrated sampling and time-weighted averages. This will be required for those samples that require laboratory analysis and currently do not have proven technology to continuously monitor. During periods of no-construction the GMRP can reduce this frequency to an acceptable interval (ensuring that limits are within the range outlined by the jurisdictions) until activity is resumed. The 24-hour sample collection criteria is an acceptable time period for the community air monitoring, and will ensure that air quality monitoring is validated and provides data that can be compared to ambient air criteria. The site-wide air quality monitoring program mandates that the duration of monitoring extend three years past surface remediation period. The remediation period is projected to be ten years (SRK Consulting, SENES, 2007). Changes to the AQMP resulting in reduced air quality monitoring would be engaged upon with affected parties and stakeholders prior to implementation. Table 6-2. Site Perimeter and Community Air Quality Monitoring Methodology, Specifications, and Frequency Averaging Current Monitor / Method Analyte Location Operating Frequency Period Specification 24 hours/day, May- Met One E-Sampler w/ PM10 PM10 15-minute Site Perimeter November (and as inlet warranted by site activity) 24 hours/day, May- Met One E-Sampler w/ TSP TSP 15-minute Site Perimeter November (and as inlet warranted by site activity) 24 hours/day, May- PM10 24-hour Site Perimeter Met One E-Sampler, PM10 inlet November (and as warranted by site activity) 24 hours/day, May- PM10 – Arsenic 24-hour Site Perimeter US EPA Method 6020Cmod November (and as warranted by site activity) 24 hours/day, May- TSP 24-hour Site Perimeter Met One E-Sampler, TSP inlet November (and as warranted by site activity) 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 14 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Averaging Current Monitor / Method Analyte Location Operating Frequency Period Specification 24 hours/day, May- TSP-Metals 24-hour Site Perimeter US EPA Method 6010Cmod November (and as (Sb, As, Pb, Ni, Fe) warranted by site activity) Met One Beta Attenuation 24 hours/day PM2.5 1-hour Community Monitor (BAM) 1020, VSCC Inlet Met One Beta Attenuation PM10 1-hour Community 24 hours/day Monitor (BAM)1020, PM10 inlet 1/3 day or 1/6 day, depending on season and TSP 24-hour Community Tisch Environmental Hi-Volume level of site activity NO2 1-hour Community (NVN only) Teledyne T200 24 hours/day NO2 24-hour Community (NVN only) Teledyne T200 24 hours/day 1/3 day or 1/6 day, TSP-Metals 24-hour Community US EPA Method 6010Cmod depending on season and (Sb, As, Pb, Ni, Fe) level of site activity 1/3 day or 1/6 day, Tisch Environmental Hi-Volume PM10 24-hour Community depending on season and with Anderson PM10 Inlet level of site activity 1/3 day or 1/6 day, PM10 – Arsenic 24-hour Community US EPA Method 6010Cmod depending on season and level of site activity 1/3 day or 1/6 day, SKC Flite2 Pump, NIOSH Asbestos 24-hour Community depending on season and Method 7400 level of site activity Continuously monitored data is to be captured by a data logger system (PM10, PM2.5, meteorological data) that is owned by the Government of Canada. The data logger will be the primary collection point for signal-based acquisition (analyzers) in the community monitoring stations. The data logger will be configured to collect and store analog signal data from analyzers and sensors operating in each monitoring station. The data logger will also control system functions like automatic calibration sequences (zero/span checks) and computes conditional averages. Data loggers record 1-hour averages of air contaminants and zero/span checks, and 15-min averages of meteorological data. Data collected by the data logger is then transmitted to a central data server via a satellite modem line. Data collected on the server is then disseminated to the project parties that have been provided authority to access the data. The data acquisition system (DAS) will poll data from the data loggers regularly and download raw data on to the data server/host computer where the collection of programs resides in order to review air quality data for validating operations of monitoring sites within the network. The DAS will allow high quality network operations and data by performing the following functions: . Allow the operator to review current and recent past data, guide the operator through calibration, maintenance, operation and troubleshooting procedures and serves at the primary on-site QA documentation archive . Facilitate flagging of data to obtain rationale from the field technicians or site operations/functions 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 15 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan § The AQC operates and manages software for equipment to ensure that data is properly captured, managed and interfaced. Beta Attenuation Monitors (BAM) 1020 configurations require Envista software to be compatible with the GNWT air monitoring website (http://aqm.enr.gov.nt.ca) where real time data is presented. (see Reporting Section 9 for more details) 7. Monitoring Type and Frequency To assist the GMRP in determining the level of air monitoring required for various remediation activities, the following approach will be implemented. (See also Appendix E) It should be noted that the below is not a reduction in to-date monitoring levels, rather it is meant as a user-friendly decision path particularly for assisting in determining the use of activity-specific monitoring. Air Quality Monitoring Level 0 – Low Risk Activities and/or conditions. Very low or no probability of dust generation. Examples of possible activities include: regular care and maintenance, snow clearing, isolated instances of minor ground disturbance (e.g. soil sampling). AQM 0 recommended monitoring requirements include: § Activity-Specific Continuous Particulate Monitoring: No monitoring required; § Site Perimeter Stations - Continuous Particulate Monitoring: No monitoring required if outside the normal operation period of May-November; § Community Stations – Continuous Particulate Monitoring: Active; § Community Stations – 24-hour Sample (TSP, Metals): Active on a 6-day NAPS schedule if outside May- November or a 3-day NAPS schedule if within May-November; § Community Stations – 24-hour Sample (PM10, Arsenic): Active on a 6-day NAPS schedule if outside May- November or a 3-day NAPS schedule if within May-November; and § Community Stations – 24-hour Sample (Asbestos): Active on a 6-day NAPS schedule if outside May- November or a 3-day NAPS schedule if within May-November. Air Quality Monitoring Level I – Low to Moderate Risk Activities that may generate some dust. Examples of possible activities include: moderate handling of low contamination soil or waste. AQM I recommended monitoring requirements include: § Activity-Specific Continuous Particulate Monitoring: No monitoring required; § Site Perimeter Stations - Continuous Particulate Monitoring with integrated filter samples: Active at least 24 hours before the activity starts (or sufficient time for monitor operation to stabilize) if outside the normal operating period of May-November; § Community Stations – Continuous Particulate Monitoring: Active on a 6-day NAPS schedule if outside May- November or a 3-day NAPS schedule if within May-November or if Site Perimeter Stations are operating; and; § Community Stations – 24-hour Sample (TSP, Metals): Active on a 6-day NAPS schedule if outside May- November or a 3-day NAPS schedule if within May-November or if Site Perimeter Stations are operating;; § Community Stations – 24-hour Sample (PM10, Arsenic): Active on a 6-day NAPS schedule if outside May- November or a 3-day NAPS schedule if within May-November or if Site Perimeter Stations are operating; and 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 16 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan . Community Stations – 24-hour Sample (Asbestos): Active on a 6-day NAPS schedule if outside May- November or a 3-day NAPS schedule if within May-November or if Site Perimeter Stations are operating. Air Quality Monitoring Level II – Moderate Risk Activities. Activities that are likely to generate and/or entrain large amounts of dust. Examples of possible activities include: moderate/major ground disturbance, earthworks (soil disposal, drilling, blasting). AQM II recommended monitoring requirements include: . Activity-Specific Continuous Particulate Monitoring: Active at upwind and downwind locations at least 24 hours before the activity starts (or sufficient time for monitor operation to stabilize); . Site Perimeter Stations - Continuous Particulate Monitoring with integrated filter samples: Active at least 24 hours before the activity starts (or sufficient time for monitor operation to stabilize) if outside the normal operating period of May-November; . Community Stations – Continuous Particulate Monitoring: Active; . Community Stations – 24-hour Sample (TSP, Metals): Active on a 6-day NAPS schedule if outside May- November or a 3-day NAPS schedule if within May-November or if Site Perimeter Stations are operating; and . Community Stations – 24-hour Sample (PM10, Arsenic): Active on a 6-day NAPS schedule if outside May- November or a 3-day NAPS schedule if within May-November or if Site Perimeter Stations are operating; and . Community Stations – 24-hour Sample (Asbestos): Active on a 6-day NAPS schedule if outside May- November or a 3-day NAPS schedule if within May-November or if Site Perimeter Stations are operating. Air Quality Monitoring Level III – High Risk Activities. Activities that are likely to generate and/or entrain large amounts of dust that may include highly contaminated dust. Examples of possible activities include AQM III recommended monitoring requirements include: . Activity-Specific Continuous Particulate Monitoring: Active at upwind and downwind locations at least 24 hours before the activity starts (or sufficient time for monitor operation to stabilize); . Site Perimeter Stations - Continuous Particulate Monitoring with integrated filter samples: Active at least 24 hours before the activity starts (or sufficient time for monitor operation to stabilize) if outside the normal operating period of May-November; . Community Stations – Continuous Particulate Monitoring: Active; . Community Stations – 24-hour Sample (TSP, Metals): Active on 3-day NAPS schedule; . Community Stations – 24-hour Sample (PM10, Arsenic): Active on 3-day NAPS schedule; and . Community Stations – 24-hour Sample (Asbestos): Active on a 3-day NAPS schedule. As the project evolves there may reason to alter the frequency of operation of the activity-specific monitors, the site perimeter monitors, and/or the community stations. Stakeholder and affected parties will be part of that discussion. See Appendix E for Air Quality Monitoring Level Decision Tree. 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 17 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Table 7-1. Air Quality Monitoring Levels Monitoring Requirements Air Quality Community: Community: Monitoring Activity- Site Community: Community: 24-hour Level Continuous 24-hour Specific Perimeter 24-hour TSP/Metals PM10/Arsenic Particulate Asbestos 6-day NAPS/3-day 6-day NAPS/3-day 6-day NAPS/3- AQM 0 - seasonal Active NAPS NAPS day NAPS 6-day NAPS/3-day 6-day NAPS/3-day 6-day NAPS/3- AQM 1 - Active Active NAPS NAPS day NAPS 6-day NAPS/3-day 6-day NAPS/3-day 6-day NAPS/3- AQM 2 Active Active Active NAPS NAPS day NAPS AQM 3 Active Active Active 3-day NAPS 3-day NAPS 3-day NAPS 8. Air Monitoring Action Levels The site perimeter monitoring program and associated action levels are a construction management tool that will be used during site activities to implement appropriate and effective emission control measures. The site perimeter air monitoring component of the air monitoring program is critical to ensure that the remediation work is carried out in a manner that mitigates atmospheric emissions to a reasonable extent. Real-time concentration averages will be continuously monitored on-site during remedial activity and the values will be compared to established short-term action levels to assist construction managers under MCM supervision in assessing or modifying site activities to prevent exceedances of project criteria. The primary objective of site perimeter air monitoring program is to monitor air emissions, on a continuous basis at or near the Project boundary. Real-time monitoring data are compared to approved, short term action levels or Risk-Based Action Levels (RBALs) developed to assist construction managers to respond and modify site activities, as appropriate, to protect local air quality in nearby communities. This section discusses the action levels and measures, to protect the local air quality from potential adverse effects of the Project. The first-line of defense is continuously monitoring on-site for the presence of visible dust plumes as a result of remedial activity. In the event that dust is detected, the condition will be assessed, with the most appropriate corrective measures taken. See the GMRP Dust Management and Monitoring Plan for further details. Results of the site perimeter air monitoring program will be compared to site-specific action levels that have been developed specifically for this project. Real-time action levels will be used to help control site operations to mitigate the potential for offsite exposures. The action levels provide a real-time screening value for the 15-minute average PM10 and TSP concentrations to be compared against. An action level is a contaminant concentration that when exceeded requires a response such as additional hand- held sampling, immediate work procedure modification and/or work stoppage until the issue is resolved or elevated concentrations are reduced below the Action Levels. AECOM has developed a Risk-Based Action Level for real-time site perimeter monitoring of PM10 for protection of the local air quality during remedial activities. Action levels were developed using a risk-based approach accounting 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 18 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan for the duration of excavation activities and the arsenic concentrations in soil and then accounting for dilution based on distance from the source and wind frequency. The site-specific particulate action levels are an indication of when it may be appropriate to initiate dust suppression activities and/or cease intrusive work for the protection of local air quality. It is understood that the primary soil contaminant at the project site is arsenic. Therefore, the particulate action levels were developed based on arsenic. Please refer to Appendix B for further information on the derivation of the action levels outlined in this section. Action levels and the response actions will be evaluated periodically with respect to the results of the YKB, NDL and NVN community monitoring program to ensure that the action levels are appropriate for controlling potential offsite emissions. If it is determined that the action levels are not appropriate they will be accordingly adjusted. Additionally, the site perimeter monitoring will allow for determining the locations that require mitigation measures. Aside from the requirements in this AQMP, occupational health monitoring and contractor monitoring may also be implemented by construction contractors within the property boundary. Occupational health monitoring and contractor boundary monitoring provide near source monitoring. This near source monitoring and wind direction data can be used by the construction manager to determine the areas with higher readings to help zone in on the key emission sources that require further mitigation. Tables 8-1, 8-2, and 8-3 show the Action Levels for the site perimeter air monitoring program during periods of remediation. 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 19 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Table 8-1. Site Perimeter Air Monitoring Action Levels – Visible Dust Monitoring Averaging Parameter Action Level Site Condition Action Required if Level Exceeded Location Period If visible dust emissions are observed on-site, the AQC is to ensure all monitors on site are functioning properly through equipment checks. Site Condition 1 – A single continues to operate. The AQC is to communicate the presence of visible Action Level observation dust to the MCM who in turn will coordinate with subcontractors to of dust in a single day. investigate the potential source and evaluate the need to implement emission control procedures and if the results require mitigation measures Visible Dust Visible dust as outlined below. Plumes observations On-site Not Applicable Implement emission control procedures. The AQC with notify the On-site onsite MCM/PSPC/CIRNAC of the condition. The AQC will ensure all monitors on Condition 2 – A second site are functioning properly through equipment checks. Real-time Action Level observation measurements at the community stations will be monitored to ensure of dust in a single day or concentrations are not increasing. an observation of dust moving off-site The MCM will investigate the potential source of air emissions and instruct subcontractors to implement emission control procedures as necessary. 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 20 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Table 8-2. Site Perimeter Air Monitoring Action Levels – PM10 Monitoring Averaging Parameter Action Level Site Condition Action Required if Level Exceeded Location Period The AQC immediately investigates to determine if the cause is equipment failure or malfunction, regional influence (e.g. weather or forest fire smoke), or local influences. The AQC then immediately notifies the MCM by phone and /PSPC/CIRNAC via email of the exceedance and air monitoring results at the community monitoring stations Condition 1 – Site continues to operate if Site Condition 3 is not met. The difference between the The MCM will immediately investigate the potential source of air emissions and upwind and 3 evaluate the need to implement emission control procedures. PM10 159 µg/m downwind results in a single Action Emission control procedures may include the following: Level exceedance (measured) in a . Establish trend of data and determine if evaluation/wait period is warranted; single day. . Apply water to area of activity or haul roads to minimize dust levels; @ downwind . Cover all or part of the excavation area; project . Change construction process or equipment that minimizes air emissions; 15-minute boundary or and/or receptor . Evaluate Site activities and mitigation measures as they relate to PM10 concentrations. The AQC immediately notifies the MCM by phone and /PSPC/CIRNAC via email of the exceedances and of air monitoring results at the community stations. (Similar to Condition 1, the AQC will also immediately investigate to determine if Condition 2 – the cause is equipment failure or malfunction, regional influence (e.g. weather or The difference forest fire smoke), or local influences.) between the upwind and 3 The MCM to initiate appropriate control measures upon notification from the AQC. PM10 159 µg/m downwind results Work shall resume within a short time period when corrective procedures are in a second Action implemented and Action Levels have returned below exceedances values. The Level exceedance MCM will evaluate work practices and determine the appropriate course of action. (measured) in a single day. The MCM will review corrective action(s) taken to date and identify additional measures to reduce air emissions. Construction practices and procedures will be examined to assess potential modifications. 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 21 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Monitoring Averaging Parameter Action Level Site Condition Action Required if Level Exceeded Location Period AQC immediately notifies the MCM by phone and /PSPC/CIRNAC via email. The MCM instructs for immediate relocation or ceasing of activities. Condition 3: The difference The site work location will be relocated or ceased until appropriate mitigative between the techniques are identified and implemented. upwind data and downwind data The MCM will review corrective action(s) taken to date and identify additional results in action measures to reduce air emissions. Construction practices and procedures will be levels being @ downwind examined to assess potential modifications. exceeded and 3 project PM10 159 µg/m 15-minute monitoring data at boundary or Work does not resume until a satisfactory mitigation strategy is formulated and the any of the receptor implemented and Action Levels have returned below exceedance values. The community MCM and PSPC/CIRNAC to agree on the proposed strategy. stations are exceeding action Mitigative measures may include the following: levels or community criteria . Temporarily stop work; due to project . Temporarily relocate work to an area with potentially lower emission levels; activities. . Slow the pace of construction activities; . Reschedule work activities. 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 22 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Table 8-3. Site Perimeter Air Monitoring Action Levels – TSP Monitoring Averaging Parameter Action Level Site Condition Action Required if Level Exceeded Location Period The AQC immediately notifies the MCM by phone and PSPC/CIRNAC via email of the exceedance and air monitoring results at the community stations. The AQC will also immediately investigate to determine if the cause is equipment failure or malfunction, regional influence (e.g. weather or forest fire smoke), or local influences. Site continues to operate if Site Condition 3 is not met. Condition 1 – A single The MCM will investigate the potential source of air emissions and evaluate the @ downwind project Action Level need to implement emission control procedures. 3 TSP 333 µg/m boundary or 15-minute exceedance receptor (measured) in a single Emission control procedures may include the following: day. . Establish trend of data and determine if evaluation/wait period is warranted; . Apply water to area of activity or haul roads to minimize dust levels; . Cover all or part of the excavation area; . Change construction process or equipment that minimizes air emissions; and/or . Evaluate Site activities and mitigation measures as they relate to TSP concentrations. The AQC immediately notifies the MCM by phone and /PSPC/CIRNAC via email of the exceedances and of air monitoring results at the community stations. (Similar to Condition 1, the AQC will also immediately investigate to determine if the cause is equipment failure or malfunction, regional influence (e.g. weather or forest fire smoke), or local influences.) Condition 2 – A second @ downwind project Action Level MCM to immediately initiate appropriate control measures. Work shall resume TSP 333 µg/m3 boundary or 15-minute exceedance within a short time period when corrective procedures are implemented and receptor (measured) in a single Action Levels have returned below exceedance values. The MCM will evaluate day. work practices and determine the appropriate course of action. The MCM will review corrective action(s) taken to date and identify additional measures to reduce air emissions. Construction practices and procedures will be examined to assess potential modifications. 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 23 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Monitoring Averaging Parameter Action Level Site Condition Action Required if Level Exceeded Location Period AQC immediately notifies the MCM by phone and /PSPC/CIRNAC via email. The MCM instructs for immediate relocation or ceasing of activities. Temporary site relocation practices or stoppage of work will be evaluated if concerns exist for air quality data at the Latham Station. The site work location will be relocated or ceased until proper techniques are identified and implemented. Condition 3: Site action The MCM will review corrective action(s) taken to date and identify additional levels are being measures to reduce air emissions. Construction practices and procedures will be @ downwind project exceeded at any of the examined to assess potential modifications. TSP 333 µg/m3 boundary or 15-minute community stations and receptor the site perimeter due Work does not resume until a satisfactory mitigation strategy is formulated and to project activities. implemented and Action Levels have returned below exceedance values. The MCM and PSPC/CIRNAC to agree on the proposed strategy. Mitigative measures may include the following: . Temporarily stop work; . Temporarily relocate work to an area with potentially lower emission levels; . Slow the pace of construction activities; . Reschedule work activities. 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 24 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan 9. Quality Assurance/Quality Control 9.1 Data Collection and Management The following sections discuss the quality assurance and quality control (QA/QC) methods carried out for the current AQMP relating to the collection and recovery of valid air quality data and include: field and lab quality controls, field and lab quality assurance checks, routine data surveillance, data handling and reduction checks, and data validation for final reporting as detailed in SLR (2018). 9.1.1 Data Validation Samples are collected and analyzed in accordance with the following methods: . US EPA National Primary and Secondary Ambient Air Quality Standards, Appendix B – Reference Method for the Determination of Suspended Particulate Matter in the Atmosphere (High-Volume Method) (40 CFR Subchapter C Part 50) . US EPA National Primary and Secondary Ambient Air Quality Standards, Appendix L – Reference Method for the Determination of Fine Particulate Matter as PM10 and PM2.5 in the Atmosphere (BAM EQPM-0798-122 and EQPM-0308-170) (40 CFR Subchapter C Part 50) . Ontario O.Reg 278/05 and NIOSH 7400 (Asbestos and Other Fibers by PCM, 1994) . Alberta Environment and Sustainable Resource Development Air Monitoring Directive (1989) and the 2006 Amendments to the Air Monitoring Directive (2006) Air monitoring data is reviewed routinely by the AQC and screened using the recommended criteria from U.S. Environmental Protection Agency (EPA) and the criteria in this AQMP. Site specific databases and spreadsheets are used to store and graphically review data collected by the Project. Monitoring locations are visually checked during routine site visits. AQC technicians verify the condition of the monitoring location during each visit. After the completion of field work, documentation of the visit is entered into an electronic station log book and/or field notes. Logbook entries and/or field notes included the following: . Time, date, and personnel at monitoring location; . Activities completed during the visit; . As-found and as-left observed conditions of monitoring equipment; and . Any unusual ambient or meteorological conditions noted during visit. AQC air quality specialists review all records received from the field. Problems or irregularities in the records are brought to the attention of the AQC technicians for further clarification. If the documentation is not sufficiently defensible, the affected data is invalidated. All data generated at the stations is reviewed according to the AQC data validation procedures. 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 25 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan 9.1.2 Site Perimeter QA/QC The site perimeter monitoring program incorporates a number of field and data QA/QC procedures to demonstrate the acceptability and quality of air quality observations. Procedures to verify equipment function and measurement accuracy follow manufacturer recommendations and include: . Daily site visits with visual inspection of sampling apparatus; . E-Sampler weekly flow, temperature, and pressure sensor verifications; . E-Sampler sampling system leak checks; . Communications system verification; and . Daily battery charge verification. Weekly sensor verifications are conducted to confirm E-Sampler instrument response to acceptability criteria for flow, temperature, and pressure. This ensures that any measurements of particulate matter concentrations near the instrument detection limits are accurate and reliable. This check ensures that the instrument is responsive to particulate matter passing through the instrument detection system. Battery charge levels are checked regularly to ensure that sufficient electrical power is available to operate the instrument for the 24-hour sampling period. Similarly, communications systems are checked continuously during operational periods to ensure that each site perimeter monitor is remotely accessible and able to communicate sampler operational status and particulate matter concentrations to the remote computer data acquisition system. As E-Sampler response to particulate matter concentrations are dependent on instrument air flow, the weekly single-point flow calibration verification is conducted to ensure that the sampler is operating within manufacturer operating specifications and that observed concentrations are accurate and defensible. To assess sampler flow, a certified flow transfer standard, of known and traceable accuracy is inserted on the sampler inlet system and the sampler was placed in normal operating mode. The weekly flow calibration verification assesses the sampler- controlled flows against performance specifications. E-Sampler instruments contain temperature and pressure sensors used to accurately report particulate matter concentrations at standard temperature and pressure. These sensors are also verified on a weekly basis using certified calibration standards. 9.1.3 Integrated Sampling Data Handling, Validation and Recovery . The data handling for integrated sampling includes production and review of chain of custody (COC) records submitted to the laboratory for analysis. The original signed paper copies of the COCs are submitted along with filter media to the laboratory for analysis of TSP, PM10, trace metals (TSP samples), and arsenic (PM10 samples). Data on the COC includes sample identification, sampling location, sampling date and time, average temperature and pressure flow conditions, average flow volume corrected to standard temperature and pressure (25 degrees Celsius [°C] and 760 mmHg), and laboratory analysis requested. . Following laboratory analysis of filter media, the laboratory provides the results to the AQC via email. Validation of the emailed analytical results includes verification for correct sample identification, sample dates, flow volumes, and concentration units. Analytical results are also confirmed against appropriate laboratory quality assurance parameters and any pertinent comments included in the laboratory analytical report remarks section that would invalidate or flag analytical results. . Provided that all filter media and chain of custody data received and resubmitted by the laboratory are found correct and accurate, laboratory analytical results are compared to available real-time site perimeter and community data from PM10 TSP, and PM2.5 particulate monitors. 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 26 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan . Further comparisons and investigations are conducted in the event that concentration results are significantly different across the site perimeter and community monitoring networks. Comparisons and investigations include review of available site perimeter and community monitoring data, station logbooks, field data sheets, calibration records, and on-site operational activity records. . Final validation of integrated sampling results includes review and accounting of all samples submitted and analytical results received, valid weekly sensor verifications, correct association of sample dates and sample identification’s, and qualitative review and comparison of meteorological and community station data for ensuring reasonably explainable sampler performance and analytical results. 9.2 Community Station QA/QC The current monitoring program incorporates a number of field and data quality assurance and control procedures to demonstrate the acceptability and quality of air quality observations. Procedures to verify equipment function and measurement accuracy follow manufacturer recommendations and include: Continuous PM2.5 and PM10 Monitors: . Daily inter-measurement correlation (PM2.5 vs. PM10 fractions); . Monthly sensor verifications (barometric pressure, sample flow, and ambient temperature); . Yearly three-day zero background check; and, . Yearly multipoint calibration of all sensors. Continuous NO2 Monitor: . Daily single point internal calibration; . Quarterly flow verifications; and, . Quarterly multipoint calibrations. Integrated High Volume Samplers: . Pre-sampling and post-sampling flow calibration verification; . Timer verification; . Inter-measurement correlation (TSP vs. PM10 fractions for particulate and arsenic); and . Quarterly multi-point flow calibrations. 9.2.1 Calibrations The community air monitoring BAM 1020 particulate matter monitors for PM2.5 and PM10 rely on a number of calibration procedures to ensure the accuracy of measurements. . An initial zero background calibration is performed on each monitor to account for local site conditions that could influence measurement accuracy near the instrument detection level. . Zero background calibrations are performed annually by operating the instrument for a minimum of 72 hours with a filter on the inlet preventing any particulate matter from entering the measurement system. 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 27 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan . An automated span verification check is performed every hour by the instrument to ensure that instrument response has not drifted due to external parameters such as temperature, barometric pressure, and relative humidity conditions. A film, representing a known instrument response, is mechanically inserted into the detector to assess instrument response. Results from the detector span verification check are captured and recorded with the hourly concentration measurement and if the verification exceeds required operating specifications data are flagged as invalid measurements. . Flow rate information is recorded by the instrument every hour for flow calibration verification. External verification of instrument flow is assessed monthly. To assess sampler flow, a certified flow transfer standard of known and traceable accuracy is inserted on the sampler inlet system when the sampler is in normal operating mode. . Monthly flow calibration verification assesses the sampler-controlled flows against performance specifications. . Monthly leak verification checks are performed to ensure that the sampler inlet system integrity has not been compromised. Monthly leak verification involves placing the instrument inlet system under negative pressure (vacuum) conditions for a period of time and assessing whether the remaining pressure is maintained within specification. . Monthly verification of the instrument’s temperature and barometric pressure measurement system are performed to ensure flow rates are accurate. The integrated high-volume samplers also require regular calibrations and data correlation, including: . Multi-point flow calibrations are conducted on a quarterly basis for the PM10 and TSP high volume samplers. Flow calibrations are completed quarterly to ensure that sampler flow accuracy and precision was representative of seasonal conditions affecting sampler flow volumes and sampler inlet performance. . An inter-measurement correlation check is done on all measurements when multiple fraction-size data are collected. PM10 concentrations are compared to PM2.5 concentrations and if concentrations do not follow anticipated trends, data analysts perform additional investigations to determine the validity of the measurements. . Due to the large volume of air sampled by the 24-hour time integrated high-volume samplers, pre-sampling and post-sampling flow calibration assessment is required to assess sampler operation throughout the entire sample collection period. The potential exists for significant amounts of particulate matter “loading” on the sample media restricting airflow and thus the volume of air sampled would be reduced leading to inaccurate calculation of pollutant concentrations. Flows that are below calibration and operational specifications would result in overestimation of 24-hour particulate matter or asbestos concentrations. Flows above calibration and operational specifications would result in underestimation of 24-hour concentrations. . Pre-sampling flow calibration verifications on the asbestos, TSP, and PM10 are conducted after installation of sample media to determine that the start-up flows of the sampler are within specification. A post-sampling flow verification calibration check for the asbestos, TSP, and PM10 samplers is conducted before removal of the sampling media following successful completion of a 24-hour sampling event. Similar to assessment of flow rates for other samplers, a flow transfer standard of known accuracy is used to measure the sampler flow rate and compare them to acceptance criteria. . Timer function which controls when a sample is collected and for how long is verified when sample media are installed for initial sample collection. After completion of a sampling event, timer verification is performed to ensure that the actual sampling period was conducted at the right time (midnight-to-midnight) and for the proper duration (between 23 and 25 hours). . Due to the generally predictable relationship between TSP and PM10 the relative concentration observations are evaluated. The inter-measurement correlation check is done on all measurements when multiple fraction- size data are collected. In this case, TSP concentrations are compared to PM10 concentrations and TSP 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 28 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan arsenic concentrations are compared to PM10 arsenic concentrations and if concentrations do not follow anticipated trends, data analysts perform additional investigations to determine the validity of the measurements. 9.2.2 Integrated Sampling Data Handling, Validation and Recovery . The data handling for integrated sampling includes production and review of COC records submitted to the laboratory for analysis. The original signed paper copies of the COCs are submitted along with filter media to the laboratory for analysis of TSP, PM10, trace metals, and asbestos. Data on the COC includes sample identification, sampling location, sampling date and time, average temperature and pressure flow conditions, average flow volume corrected to standard temperature and pressure (25°C and 760 mmHg), and laboratory analysis requested. . Following laboratory analysis of filter media, the laboratory provides the results to the AQC via email. Validation of the emailed analytical results includes verification for correct sample identification, sample dates, flow volumes, and concentration units. Analytical results are also checked for appropriate laboratory quality assurance parameters and any pertinent comments included in the laboratory analytical report remarks section that would invalidate or flag analytical results. . Provided all filter media and chain of custody data received and resubmitted by the laboratory are found correct and accurate, laboratory analytical results are compared against available continuous community data from PM10 and PM2.5 BAM particulate monitors. Analytical results are also checked and compared across all community and site perimeter stations for reasonable correlations. . Further comparisons and investigations are conducted in the event that concentration results are significantly different across community and fence line monitoring networks. Comparisons and investigations include review of available site perimeter and community monitoring data, station logbooks, field data sheets, calibration records, and on-site operational activity records. Final validation of integrated sampling results included review and accounting of all samples submitted and analytical results received, valid multi-point flow calibrations, correct association of sample dates and sample identification’s, and qualitative review and comparison of meteorological and community station data for ensuring reasonably explainable sampler performance and analytical results. 9.2.2.1 Laboratory QA/QC Laboratory work is to be carried out by independent subcontracted analytical facilities that have QA/QC procedures in place equivalent to accreditation based on the Canadian Standard CAN/CSA-Z753, extension of the international standard ISO/IEC Guide 17025:2005. 9.2.3 Preventative and Corrective Maintenance Performing regular system checks and calibrations will ensure that the sampling equipment is working according to specifications. Preventative maintenance is an important tool in creating a proactive environment where QA and reliability are a top priority in providing fast responses and accurate results. The routine system checks will work towards providing this preventative maintenance step. If initial corrective maintenance steps prove insufficient in troubleshooting for the scope of a particular event, the AQC will have a support team of experts on stand-by, ready to help with the maintenance issue. Preventative Maintenance will be done as per manufacturer specification for each instrument in the network. Repairs will be recorded and will help to determine if preventative measures are working and will assist in determining which instruments should be ear marked for replacement. 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 29 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Corrective maintenance will be performed as required. Records will be kept of corrective maintenance and will also be recorded as part of our QA/QC program. Minor repairs will be conducted as part of the ongoing operation and maintenance program. Maintenance that occurs during the course of a routine calibration will be performed at that time. 9.2.4 Equipment Inventory An inventory database is maintained to keep track of equipment parts that have been replaced, ordered, required to be ordered and in storage. This will ensure that the components and parts for the instruments are available when they are needed, minimizing delays in data collection and reporting, ensuring continuous, uninterrupted monitoring. By having consistent and reliable monitoring equipment and by extension data will be upheld with a high confidence level. The equipment inventory will be implemented providing a complete record of manufacturer and supplier information, dates and locations of monitor usage, monitor performance, maintenance and or/cleaning events, calibration documentation and other pertinent information. Air monitoring stations are equipped with monitor manuals for reference. The manuals contain performance specifications, procedures and recommended maintenance. A critical spare parts inventory supply containing consumables related to the operations of the air quality network is required. Consumables include inlet filters, tubing, fittings and scrubber materials. Certification, calibration or records verifying that the product used adheres to a specific assured quality or has been approved for use will be maintained. 10. Reporting The GMRP has the potential to impact existing local air quality due to activities on site. The effectiveness of mitigation efforts on local air quality will be monitored on an ongoing basis and results will be reported on a regular basis, as outline below. In order to incorporate changes to regulatory requirements or to respond to changes in the GMRP or monitoring conditions, the AQMP and associated protocols shall be reviewed and revised periodically (at least every three years) during the GMRP and/or associated ambient air monitoring. 10.1 Real-Time Reports The network of site perimeter and community monitors measuring PM10, TSP and/or PM2.5 will be capable of logging minimum, maximum and average concentrations over predetermined time intervals via an external data logger. This network of monitors shall be capable of transmitting results directly to a control command data management center where real-time information from the monitors are converted quickly into practical information for rapid on-site decision-making requirements. The management center shall provide both visual and audible alarms. Alarms can then be acknowledged, detectors can be enabled and disabled, as well as event logs and event log history can be viewed. Real-time information concerning daily operations shall be provided directly to the AQC for evaluation and action as required. Any exceedances are to be immediately checked by on-site AQC staff to 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 30 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan determine site conditions, equipment functionality, and any site activity that may be a contributing factor. Following this initial investigation, immediate email notification for any exceedance or warning at a site perimeter or community station is required, with details of the investigation and probable cause, if known or suspected. The email notification is sent to the MCM and PSPC/CIRNAC, as well as relevant contractor leads on site. 10.2 Daily Reports The daily reports of site perimeter and community station monitoring data shall be submitted to the MCM and PSPC/CIRNAC within two business days following receipt of data by the AQC and shall include at a minimum the following information: . A list of ongoing and/or upcoming activities on site relevant to air quality monitoring. (It is important for the AQC to have a solid understanding of site activity levels in order to quickly identify possible sources of any warning or exceedance values.) . Summary table of real-time site perimeter monitoring data for all active stations: Table 10-1. Summary of Real-Time Site Perimeter Monitoring Data RBAL 15- Maximum 15- Time Interval RBAL 15- Maximum 15- Time Interval minute Average minute Average Maximum PM10 minute Average minute Average Maximum TSP PM10 Conc. PM10 Conc. Conc. TSP Conc. TSP Conc. Conc. Exceedance1 (µg/m3) Measured2, 3 Exceedance1 (µg/m3) Measured2, 3 A-North Yes/No Yes/No B-Town Yes/No Yes/No C-Northwest Yes/No Yes/No D-Beach Yes/No Yes/No E-A1C1 Yes/No Yes/No F-Marina Yes/No Yes/No G-West Yes/No Yes/No H-NW Pond Yes/No Yes/No I-South Pond Yes/No Yes/No 1. 3 3 The RBAL for 15-minute average concentrations for PM10 and TSP are 159 µg/m and 333 µg/m , respectively. 2. Data is in Mountain Standard Time format – no adjustment for daylight savings time. 3. Time intervals for the maximum 15-minute average concentration are marked with NA for days with no periods greater than 1 µg/m3. . Summary table of 24-hour average continuous concentrations at community stations: Table 10-2. Summary of 24-Hour Average Continuous Concentrations 1 2 PM2.5 PM10 NDL Station YCC Station NVN Station 1. 3 The GNWT 24-Hour standard for 24-Hour average concentrations for PM2.5 is 28 µg/m . 2. 3 The Ontario 24-Hour standard for 24-Hour average concentrations for PM10 is 50 µg/m . 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 31 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan . Summary table of activity-specific monitoring data, if applicable: Table 10-3. Summary of Activity-Specific Monitoring Data RBAL 15-minute Average Maximum 15-minute Average Time Interval Maximum PM10 1 3 2, 3 PM10 Conc. Exceedance PM10 Conc. (µg/m ) Conc. Measured Station ID Station ID 1. The RBAL15-minute average Exceedance Concentration has been defined as 159 µg/m3. 2. Derivation calculated using Health Canada’s Toxicological Reference Values in “Real-time Site Perimeter Monitoring Risk-Based Action Level (RBAL) for PM10” (AECOM, 2013) 3. Derived from toxicological references for the hypothetical on-site worker/trespasser, chronic criterion based on protection against both an incremental carcinogenic risk of 1 x 10-5 (Health Canada, 2004) using the Health Canada Inhalation Unit Risk Factor. . Table and/or list indicating meteorological conditions (temperature, wind, and any other notable meteorological conditions) and site activities; and . Results exceeding criteria shall be clearly highlighted and correlated to site activity as appropriate, as well as corrective measures taken and resulting outcome(s). . The purpose of the daily activity report is to provide ongoing snapshots of the air quality monitoring program and the impacts of any site activity. 10.3 Weekly Reports Weekly summary reports will be prepared by the AQC with submission no later than five business days following the week in which the sampling took place. The contents of the Weekly Reports should contain at minimum the following information from site perimeter and community monitoring stations, as well as activity-specific monitoring if applicable: . Site perimeter monitoring: . Details on any 15-minute average PM10 concentrations above the established RBAL at each station, as applicable. This is to include the measured concentrations, actions taken by the AQC to determine the cause, and the outcome. If the exceedance is determined to be weather related, this is to be stated. If no exceedances are measured this is also to be stated. . Details on any 15-minute average TSP concentrations above the established RBAL at each station, as applicable. This is to include the measured concentrations, actions taken to determine the cause, and the outcome. If the exceedance is determined to be weather related, this is to be stated. If no exceedances are measured this is also to be stated. . Laboratory results for TSP, PM10 and trace metals (including arsenic) analyses that were returned during the previous week, once validated. If all results were below detection limit and/or below the referenced standard, this is also to be stated. . Community Stations: . Details on any real time PM2.5 or PM10 24-hour average concentration above the referenced standards measured at any of the community stations that week. 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 32 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan . Laboratory results for TSP, PM10 and trace metals (including arsenic) analyses that were returned during the previous week, once validated. Date of sampling event to be specified. If all results were below detection limit and/or below the referenced standard, this is also to be stated. . Laboratory results for asbestos analyses that were returned during the previous week, once validated. Date of sampling event to be specified. If all results were below detection limit and/or below the referenced standard, this is also to be stated. . Details on any NO2 concentrations measured at the Niven Lake community station above the NWT Ambient Air Quality 24-hour standard of 106 parts per billion (ppb) or the 1-Hour Standard of 213 ppb. Summary table of daily NO2 concentrations at Niven Lake Community Station Table 10-4. Summary of Daily NO2 Concentrations at Niven Lake Community Station Date Maximum One-hour Average (ppb) 24-hour Average (ppb) Date 1 Date 2 Date 3 Date 4 Date 5 Date 6 Date 7 . A general description of site activities and other potential offsite emission sources in terms of the monitoring events; . General operation: . A data validation report, including data availability for site perimeter, community, and activity specific monitors (as applicable); . An equipment maintenance report; . Meteorological summaries including a comparison of on-site measurements with airport measurements; . Exceedances of action levels; . Discussion of exceedances with regard to health, environment and source of emission, and mitigation steps undertaken by the contractor; . Discussion concerning geographic variation of results; . Evaluation of data with regard to historical data; and . Tables presenting the weekly, program-to-date statistics. 10.4 Weekly Data Reports Weekly data reports are compiled for site perimeter and community air monitoring stations in excel format for upload to the GNWT Air Quality Monitoring Network website (aqm.enr.gov.nt.ca). Weekly data reports of QA/QC’d data are emailed to the MCM, PSPC, CIRNAC, and GNWT. 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 33 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan 10.5 Annual Reports The AQC shall prepare an annual summary report for each calendar year, to be submitted to the MCM, PSPC and CIRNAC by March 15th of the following year at the latest. The report will include at a minimum the following for community, site perimeter and activity specific monitoring: . Executive summary; . Plain language summary . Approach and methodology used; . A description of the data collection programs; . A summary of data quality issues; . A complete statistical evaluation and reporting of the data; . An analysis of trends and seasonal distinctions; . A discussion of any exceedances; . A comparison of the data to annual historical conditions; . A comparison of the data to the GNWT NAPS air quality monitoring station; . An overall air quality statement based on the air quality results; . Conclusions and recommendations; and . Appendices: . Calibration and instrument certification records . Laboratory analytical reports 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 34 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan 11. References Aboriginal Affairs and Northern Development Canada (AANDC). 2013. Giant Mine Meteorological Data 2009-2013. Aboriginal Affairs & Northern Development Canada & Government of the Northwest Territories. 2012. Giant Mine Environmental Assessment - Closing Comments. AECOM. 2010. Project Environmental Protection Plan, Document # 97918-GEN-EPP-N-001-RD AECOM. 2010. Environmental Management Plan, Document # # 97918-GEN-EMP-N-001-R2 AECOM, 2010. 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Air Quality Monitoring at Giant Mine Site - Yellowknife a Baseline Study. Volume 5. SENES Consultants Limited. 2009. Air Quality Monitoring at Giant Mine Site - Yellowknife a Baseline Study. Volume 6. SENES Consultants Limited. 2010. Air Quality Monitoring at Giant Mine Site - Yellowknife a Baseline Study. Volume 7. SENES Consultants Limited. 2011. Air Quality Monitoring at Giant Mine Site - Yellowknife a Baseline Study. Volume 8. SENES Consultants Limited. 2012. Air Quality Monitoring at Giant Mine Site - Yellowknife a Baseline Study. Volume 9. SENES Consultants Limited. April 2012. Calpuff air dispersion modelling for the giant mine remediation project. SRK Consulting Engineers and Scientists; SENES Consultants Ltd. July 2007. Giant Mine Remediation Plan. Tisch Environmental TSP high volume air sampler. February 2013. Available at: http://tisch-env.com/products/9- High-Volume-TSP-Total-Suspended-Particulate-Samplers/63-TE-5170-V/default.asp Tisch Environmental PM10 high volume air sampler. February 2013. Available at: http://tisch-env.com/products/10- High-Volume-PM10-Particulate-Sampler/55-TE-6070DV/default.asp TSI. 2013. DustTrak DRX Aerosol Monitor 8534. Available at: http://www.tsi.com/ProductView.aspx?id=21994 US Environmental Protection Agency. June 1999. Sampling of Ambient Air for Total Suspended Particulate Matter and Using High Volume (HV) Sampler. Available at: http://www.epa.gov/ttnamti1/files/ambient/inorganic/mthd-2-1.pdf 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 37 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan US Environmental Protection Agency. May 2012. Plenary Session – Technical Program Update. FEM Overview. http://www.epa.gov/ttnamti1/files/2012conference/4Hanley.pdf US Environmental Protection Agency. 2007. Method SW-6020. Available at: http://www.epa.gov/osw/hazard/testmethods/sw846/pdfs/6020a.pdf US Environmental Protection Agency. 2012. List of Designated Reference and Equivalent Methods. Available at: http://www.epa.gov/ttn/amtic/files/ambient/criteria/reference-equivalent-methods-list.pdf US Environmental Protection Agency. 2009. Method 7E – NOx – Instrumental. Technology Transfer Network Emission Measurement Center. Available at: http://www.epa.gov/ttn/emc/methods/method7e.html US Environmental Protection Agency. 1994. Asbestos Sampling - SOP 2015. Available at: http://www.epa.gov/region9/toxic/noa/eldorado/pdf/EPA-ERT-Asbestos-Sampling-SOP-2015.pdf WorkSafeBC. September 2010. Guidelines Part 5 – Background Information. Available at: http://www2.worksafebc.com/publications/ohsregulation/guidelinepart5.asp?reportid=19335 Workers’ Safety and Compensation Commission. 2000. General Safety – English/French (NT). Available at: http://www.wcb.nt.ca/YourWSCC/Resources/Documents/Safety%20Regs/General_Safety_NWT.pdf Workers’ Safety and Compensation Commission. May 2012. Asbestos Abatement. Northwest Territories & Nunavut Codes of Practice. Available at: http://www.wscc.nt.ca/Documents/Code%20of%20Practice%20on%20Asbestos%20Abatement.pdf York University. March 2010. Asbestos Management Program. Available at: http://www.yorku.ca/dohs/documents/AsbestosManagement.pdf 405-Air Re-Evaluate-47-RPT-0001-Rev3_20190201 (Air Quality Monitoring Plan).Docx 38 Imagine it. AECOM Delivered. Appendix A AQMP Monitoring Locations Last saved by: KNOTTJ (2019-02-01) Last Plotted: Fri Feb 01, 2019 Project Management Initials: Designer: Checked: Approved: ANSI B 279.4mm x 431.8mm Filename: P:\60577312\900-CAD_GIS\920-929 (GIS-GRAPHICS)\02_MXDS\SITE\H001_60577312_MONITORINGSTATIONS.MXD modifies drawing this without express AECOM's written consent. responsibility,and denies any whatsoever,liability to that any party no accepts AECOM agencies. reviewing governmental by use for or law by required as client, its and AECOMby agreed as except parties, third by upon relied or client reproduced used,AECOM's be of not may and use the for prepared been has drawing This Ortho-Imagery:MapsBing Aerial Basemap:SLR Legend Yukon . ! . ! Columbia British 300 Site Perimeter Site Station Monitoring Perimeter Site Station Monitoring Community 150 NAD 1983 UTM Zone 11NZone UTM 1983 NAD Northwest Territories 0 Alberta ² ^ _ Key Map Key Site 1:30,000 300 Saskatchewan 600 Nunavut Manitoba 900 m GIANT MINE REMEDIATION PROJECT MONITORING STATIONS AIR QUALITY MONITORING PLAN PUBLIC WORKS AND GOVERNMENT SERVICES CANADA Project No.: 60577312 Date: 2019-02-01 Figure: 1 Imagine it. AECOM Delivered. Appendix B Action Level Derivation Memo AECOM A:COM 200 – 6807 Railway Street SE 403 254 3301 tel Calgary, AB, Canada T2H 2V6 403 270 9196 fax www.aecom.com April 12, 2013 Via: Email Belinda Campbell Public Works and Government Services Canada Dear Belinda Campbell: Project No: 60284490 Regarding: Real-time Fenceline Monitoring Risk-Based Action Level (RBAL) for PM10 AECOM has developed a Risk-Based Action Level (RBAL) for real-time fenceline monitoring of inhalable particulate matter (PM10) for protection of the general public during remedial activities to be performed at the Giant Mine site. This memo provides the derivation of site-specific particulate action levels as an indication of when to initiate dust suppression activities and/or cease intrusive work for the protection of the general public. It is understood that the primary soil contaminant at the project site is arsenic. Therefore, the particulate action levels were developed based on this contaminant. 1. Risk-Based Particulate Exposure Concentration Associated with Arsenic In order to develop an action level for particulates, it was first necessary to determine a risk-based, acceptable concentration in air (AAC) for arsenic. No Canada Wide Standard is available for arsenic. The Northwest Territories Department of Environment and Natural Resources has developed a Guideline for Ambient Air Quality Standards (January 2011) for carbon monoxide, fine particulate matter ( as PM2.5), ozone, nitrogen dioxide, sulphur dioxide and total suspended particulate. However, the guideline does not outline guidelines for arsenic. The primary health concern with exposure to long-term airborne emissions of arsenic is cancer risk. For the basis of developing a risk-based particulate exposure concentration, an incremental lifetime cancer risk screening level of one chance in 100,000 (1 x 10-5) was used. This lifetime cancer risk is consistent with the risk goal used by Health Canada for site remediation. Using the Health Canada Unit Risk factor for arsenic of 0.0064 (µg/m3)-1 (Health Canada 2004), which corresponds to 70 years of exposure, the AAC for arsenic concentration corresponding to the Giant Mine site remediation, were it to last as long as ten years, is 0.011 µg/m3 [(1 x 10-5 / 0.0064 (µg/m3)-1) x (70 yr / 10 yr)]. This risk-based arsenic concentration is highly conservative considering that the planned excavation period is only two to three years and it assumes that exposures occur 24 hours/day, 365 days/year. For arsenic, an AAC was calculated by using the annual average concentration of 0.011 µg/m3 and then adjusting for the exposure duration and frequency based on the anticipated remediation Appendix C RBAL Memo 20130627.Docx Page 2 A:COM April 12, 2013 activities. It is expected that intrusive soil excavation activities which might generate site-related particulates in the air would occur 12 hours/day (an expected work day) and 245 days/year (7 days/week for 35 weeks/year). Note that the assumption of 12 hours/day accounts for potential dust- generating site activities that may at times extend beyond a standard 8 hour work day and that steps will be taken to help prevent wind-blown dust at other times when no remediation activities are taking place. The Health Canada risk based arsenic concentration of 0.011 µg/m3 can then be modified to derive an AAC, as indicated below: 3 0.01 1 µg/m Acceptable Air Concentration 0.0328 µg/m 3 12hr 245d 24hr 365d In the next step, the PM10 action level was calculated by dividing the AAC by a soil concentration for arsenic. The PM10 action level was calculated by conservatively assuming that 100% of the arsenic in soil would become airborne. In other words, the concentrations of arsenic in particulates would mirror the concentrations in soil. The particulate concentration was calculated using the following equation: (A AC) (C) (AAC) Level ActioneParticulat Level SC Where: C = Conversion factor, 1 x 106 mg/kg AAC = Acceptable Air Concentration, 0.0328 µg/m3 SC = Soil Concentration, 6,120 mg/kg (95th percentile arsenic soil concentration) The particulate concentration based on the AAC for arsenic of 0.033 µg/m3 and a 95th percentile arsenic soil concentration of 6,120 mg/kg is 5.36 µg/m3. The 95th percentile was determined based on data for 515 soil samples obtained from the document “Distribution of Arsenic in Surficial Materials: Giant Mine” (Golder Associates, 2005). The location and material type sampled is outlined in Table 1. The statistical summary of all 515 samples is outlined in Table 2 below. Table 1 Summary of Sampling Locations and Associated Material Type Investigated Areas Material Type Mill Mixed Fill, and Clay with Silt and Sand West of the Central Tailings Tailings Containment Area West of Tailing Retreatment Clay with Silt and Sand Plant West of Settling Pond Tailings, Rock Fill, Mixed Fill, Refuse Propane Tank Farm Clay with Silt and Sand Appendix C RBAL Memo 20130627.Docx Page 3 A:COM April 12, 2013 Investigated Areas Material Type Rock Fill, Mixed Fill, Clay with Silt and Sand, Townsite and Soil with Organic Matter Townsite Road Rock Fill, and Soil with Organic Matter Tailings, Mixed Fill, and Soil with Organic Dam 7 to Yellowknife Bay Matter East of Dam 3 Mixed Fill, and Clay with Silt and Sand Table 2 Statistical Summary of the Arsenic Soil Concentration Data Points (515) Maximum (mg/kg) 87000 Minimum (mg/kg) 5 Average (mg/kg) 1687.27 95th Percentile (mg/kg) 6120 2. Adjustment Factors for Long-Term Community Exposure 3 As demonstrated above, a continuous PM10 risk-based exposure concentration of 5.4 µg/m during every hour of remediation for 12 hours a day would correspond with the established annual health- based objective for arsenic. The exposure concentration will be used as a basis to establish an action level for 15-minute average real-time “fenceline” monitoring. Because the objective of the real-time monitoring is to make continuous short-term (15 minute average) measurements close to potential dust-generating remedial activities, it is unrealistic to assume that long-term average concentrations in nearby communities would be at the levels. Figure 1 shows the location of three of the arsenic contaminated areas (areas 6, 7 and 8) with respect to three nearby population areas located to the north and northeast of Yellowknife. The closest distance between any of the three populated areas and the contaminated sites is 1.77 km, between Arsenic Area 6 and Resident Area A. The three arsenic areas are in the sector ranging from the west-northwest to north-north with respect to the three nearby populated areas. In establishing a conservative RBAL, (i.e., health-protective) adjustments are required to convert a peak 15-minute concentration at a fenceline to long-term average community exposure. The required adjustments include: 1. An averaging time adjustment factor (ATF) to relate peak 15-minute concentrations to work-day (12 hr) concentrations at the fenceline; 2. The dilution adjustment factor (DAF) addresses the degree to which dispersion will reduce the airborne fugitive dust concentrations by the time emissions reach nearby residential areas; and 3. The wind frequency factor (WFF) accounts for the long-term wind patterns for the time of day and time of year that remediation will take place in reference to the location of nearby populated areas. Appendix C RBAL Memo 20130627.Docx Page 4 A:COM April 12, 2013 Using these adjustment factors, the proposed action level will then be computed according to: 3 RBAL PM10 15-minute real-time action level = 5.36 µg/m x ATF x DAF x WFF (Equation 1) Figure 1: Locations of Arsenic Contamination Closest to Residential Areas Appendix C RBAL Memo 20130627.Docx Page 5 A:COM April 12, 2013 Averaging Time Adjustment Factor (ATF) Experience monitoring of PM10 near fugitive dust sources indicate that 15-minute average concentrations are highly variable. Given that the objective of the monitoring plan is to ensure that actions are taken to generally limit short-term concentrations at the fenceline below the RBAL, it has been conservatively assumed that the 12-hour work-day average concentration will not exceed 90% of the RBAL. This assumption results in an ATF of 1.11 (1/0.90). Dilution Adjustment Factor (DAF) The DAF is defined as the relative degree of dilution from the fenceline monitor to the nearest residential area. DAF was based on the modeled 1-hour average downwind concentration associated with a ground level area source, representing a typical active excavation area. Model receptors were placed at two distances corresponding to the fenceline where monitoring is taking place and the closest residential area, where long-term exposure could occur. The DAF is then computed the ratio of the modeled concentration at the fencelince receptor and the residential receptor. For this calculation it is conservatively assumed that there is no deposition of PM10 that would further reduce airborne concentrations at the residential receptor. For a ground level source, the modeled concentration pollutant is directly proportional to the emission rate and inversely proportional to the wind speed. Thus, the selection of emission rate (1 g/sec) and wind wind speed (1 m/sec) do not affect the ratio of the modeled concentrations at the fenceline and residential receptors. The model parameters that affect the DAF are the size of the area source, distance of the fenceline and residential receptors and the atmospheric stability class and dispersion environment (urban or rural), which affect the rate of dispersion. U.S. EPA SCREEN3 model was applied with a rural dispersion environment. In the rural mode SCREEN3 applies the standard Pasguill Gifford Taylor (PGT) dispersion coefficients. Given that remediation activities will take place during daylight hours SCREEN3 was applied using neutral atmospheric dispersion conditions (stability category D). During most of a typical day the atmosphere is unstable (categories A, B, and C) which would result in greater dilution. Stable conditions which occur at night result in a lesser dilution. Thus, the use of neutral stability is suitably conservative as it results in the least degree of atmospheric dispersion that would occur during daylight hours. A 0.001 g/sec/m2 emission rate and 1 m/sec wind speed was applied in SCREEN3. The screening model was used to estimate the degree of downwind dilution that would occur at the closest residential location (Resident Area A) associated with remediation taking place at Arsenic Area 6, 1.7 km to the west-northwest. For this calculation it is assumed that primary fugitive dust generating activities are taking place within a 300 m square area, corresponding to a portion of Arsenic Area 6, closest to community receptors. The fenceline monitor was assumed to be located 100 m from the downwind edge of the area source (i.e., 250 m from the center of the area source). The Dilution Adjustment Factor was computed as the ratio of the SCREEN3 modeled concentration at the fenceline receptor (2.61E+04 µg/m3) to the modeled concentration at the receptor 1.7 km downwind (4.38E+03 µg/m3). This ratio results in a DAF of 5.96. This DAF (in Equation 1) can further be adjusted to incorporate people who may be present near the fenceline of an active excavation area for recreational purposes. The DAF for these recreational receptors will be smaller than the 5.96 and could be as small as 1 due to minimal distance Appendix C RBAL Memo 20130627.Docx Page 6 A:COM April 12, 2013 attenuation. The recreational areas considered include the Marina and Ingraham Trail. To address recreation that may occur close to the fenceline, the DAF would be replaced with the Daily Exposure Factor (DEF). The (DEF) in Equation 1 and will reflect the number of hours per day spent at the location (assumed to be less than 12 hours). 12hrs/day site activity Daily Exposure Factor (DEF) H Where: H = Hours per day a person is at the fenceline A value of 2 hours per day for H would result in a DEF of 6, which is roughly equivalent to the currently modeled DAF value of 5.96. Wind Frequency Factor (WFF) To estimate the wind frequency factor a long-term wind rose was developed for non-winter meteorological seasons (April through November) during the hours of 7 AM to 7 PM, approximating the time of day and time of year that remedial activities are expected to occur. For this analysis five years of hourly meteorological data (2008-2012) was obtained from the nearby Yellowknife meteorological station. The resulting wind rose, shown in Figure 2 was then used to estimate the fraction of the time during these periods that winds are likely to transport fugitive emissions in the wind direction of the nearby populated areas (WNW, NW, NNW and N). The wind rose indicates that winds from this sector are expected to occur about 22.3% of the time. This indicates that about 78% of the time the concentration measured at the downwind fenceline will not affect the annual average concentration at the residential areas because these areas are not downwind of any of the arsenic remediation sites. The WFF accounts for the contribution of activities to annual average concentrations by dividing the total frequency (100%) by the frequency of transport to the nearby populated areas (22.3%). Thus, the WFF is 4.48 (100/22.3). 3. Risk-Based Action Level The RBAL for PM10 is computed by applying Equation 1. RBAL = 5.36 µg/m3 x 1.11 x 5.96 x 4.48 = 159 µg/m3. This RBAL is also applicable to recreational users close to site activities when considering the same WFF outlined previously and 2 hours of exposure per day. TSP represents particles with an aerodynamic diameter less than 30 µm. TSP is not directly associated with human health effects because particles between 10 and 30 µm in diameter are not inhaled into the lungs. Thus, a human health RBAL was developed only for inhalable PM10. Fenceline criteria for TSP will be outlined in the site-wide air monitoring plan and will be based on nuisance effects. Appendix A and Figure 2 provide the dispersion modeling and wind frequency information used to develop the DAF and WFF, respectively. Appendix C RBAL Memo 20130627.Docx Page 7 A:COM April 12, 2013 Figure 2: Wind Rose for Yellowknife Representative of Remediation Period W IDiFOSe: PLOT: OJSR.AY: Yellow kn if e, Northw est Territori es, Canada W ind Si><'<'d 2009-2012, Ap ril t o November D i"ection {Dl owing fro m) Frequency.of W i nd 15% . Directi0 fi s Affecting ,. Popµl at ed Areas, 22'.~% 12% , W IN:D SPEED (mis) , , ~ 11.1 -- .. -- .. -- - ,. -'-',. D 8.8 - 11 .1 • 5.7 - &8 :sOJ TH 3.6 - 5.7 - .. .. - --- ~ -- ,. - • •D 2.1 - 3.6 D 0,5 - 2 1 Ca1ms: 1.-21'7.. COW.iiN'TS : co.,,::,Al',.Y " _ Sta.rt Date: 8/31 12!l 09 -11 : IIO AECO M Time Peri od : 7am · 7pm End Date: 11 /300012 - 19:00 MO!l:.LER: Ajeev Mark Ramnaut h 0\1.iM WUm s: TOTA!.. W NT: 137% 10708 hrs. AVG. WI IDS?ffiD: CATE: PRo..Ecr 3.60 m/ s 4181 2013 60284490 Appendix C RBAL Memo 20130627.Docx Page 8 A:COM April 12, 2013 If you have any questions, please do not hesitate to contact the undersigned. Sincerely, AECOM Canada Ltd. Aileen Raphael, P.Eng. David W. Heinold, CCM. Canada West Practice Lead – Atmospheric Services Sr. Air Quality Meteorologist [email protected] [email protected] AR:kw cc Ajeev Mark Ramnauth, EIT. Appendix C RBAL Memo 20130627.Docx Page 9 A:COM April 12, 2013 4. References Aboriginal Affairs and Northern Development Canada (AANDC). 2013. Giant Mine Meteorological Data 2009-2013 Golder Associates. October 2005. Distribution of Arsenic in Surficial Materials: Giant Mine. Giant Mine Remediation Team and SRK Consulting Health Canada. 2004. Federal Contaminated Site Risk Assessment in Canada. Part II: Health Canada Toxicological Reference Values. Environmental Health Assessment Services Safe Environments Programme, Health Canada. Available at: http://www.hc-sc.gc.ca/ewh- semt/alt_formats/hecs-sesc/pdf/pubs/contamsite/part-partie_ii/part-partie_ii-eng.pdf US EPA. November 2006. Aggregate Handling and Storage Piles. Available at: http://www.epa.gov/ttn/chief/ap42/ch13/final/c13s0204.pdf Appendix C RBAL Memo 20130627.Docx A:COM Memo Appendix A - Screen 3 Model Output and Input Used to Compute the Dilution Adjustment Factor 04/08/13 10:29:49 *** SCREEN3 MODEL RUN *** *** VERSION DATED 95250 *** 300 m area source SIMPLE TERRAIN INPUTS: SOURCE TYPE = AREA EMISSION RATE (G/(S-M**2)) = .100000E-02 SOURCE HEIGHT (M) = .0000 LENGTH OF LARGER SIDE (M) = 300.0000 LENGTH OF SMALLER SIDE (M) = 300.0000 RECEPTOR HEIGHT (M) = .0000 URBAN/RURAL OPTION = RURAL ANGLE RELATIVE TO LONG AXIS = .0000 BUOY. FLUX = .000 M**4/S**3; MOM. FLUX = .000 M**4/S**2. *** STABILITY CLASS 4 ONLY *** *** 10-METER WIND SPEED OF 1.00 M/S ONLY *** ********************************* *** SCREEN DISCRETE DISTANCES *** ********************************* *** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES *** DIST CONC U10M USTK MIX HT PLUME MAX DIR (M) (UG/M**3) STAB (M/S) (M/S) (M) HT (M) (DEG) ------250. .2612E+05 4 1.0 1.0 320.0 .00 0. 1700. 4384. 4 1.0 1.0 320.0 .00 0. *************************************** *** SUMMARY OF SCREEN MODEL RESULTS *** *************************************** CALCULATION MAX CONC DIST TO TERRAIN PROCEDURE (UG/M**3) MAX (M) HT (M) ------SIMPLE TERRAIN .2612E+05 250. 0. *************************************************** ** REMEMBER TO INCLUDE BACKGROUND CONCENTRATIONS ** *************************************************** Imagine it. AECOM Delivered. Appendix C Analysis of 2013-2017 Monitoring Data (Including Meteorological Data) AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Appendix C C1.1 Summary of AECOM AQMP Re-Evaluation Technical Memorandum A technical memorandum was written by AECOM to analyze the data collected from site perimeter and community stations from 2013-2017. The air quality monitoring was conducted according to the Air Quality Monitoring Plan (AQMP) (AECOM, May 2013) to measure any impacts of the onsite activities on ambient air quality. A summary of the key findings and recommendations can be found in Table C-1 below: Appendix C - Analysis Of 2013-2017 Monitoring Data.Docx C-1 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Appendix C Table C-1. Summary of Key Findings and Recommendations Document Item Current Status Recommended Change Reference Overall the site perimeter and community stations have excellent data availability. The stations for these two program components respond similarly to large-scale events such as during elevated particulate concentrations associated with wildfires, and correlations between elevated readings between stations occur frequently, indicating that the system is functioning well as a coordinated network. Considering the spatial distribution of the different stations across the air quality monitoring network, this level of commonality is remarkable and supports the conclusion of accuracy and repeatability from station to station. General Comments None General Outside of wildfire data there were very few exceedances of the RBAL on site perimeter stations and no exceedances of the RBAL on the community stations. Across all years, but most notably in 2014 and 2017, a large portion of the PM10 concentrations above baseline at the site perimeter monitors were measured while the wind was blowing predominantly from the south, toward the Site. This is indicative of offsite particulate matter blowing across the site from the south. There were no exceedances of the air quality criteria for arsenic at any of the site perimeter or community stations during the reviewed monitoring period (June, 2013 to December, 2017). Appendix C - Analysis Of 2013-2017 Monitoring Data.Docx C-2 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Appendix C Document Item Current Status Recommended Change Reference AECOM recommends that the AQMP be reviewed periodically and revised as required. A periodic review of the AQMP will allow the plan to be adapted for changes in the remedial activities and monitoring requirements. AQMP Review and The AQMP (AECOM, 2013) does not specify requirements General Revision for periodic review and revision. The timing of the AQMP re-evaluation should be coordinated with the requirements of other monitoring programs (e.g. Aquatic Effects Monitoring Program). AECOM recommends that a formal review period of 3 years be added to the next AQMP revision, or at an interval that aligns with the requirements of other monitoring programs. The AQMP (AECOM, 2013) identifies the goals of the remedial phase air monitoring program as: 1. To measure air quality in the vicinity of remediation emissions to confirm overall compliance with established criteria. Real-time concentration averages will be continuously monitored on-site during remedial No changes are recommended; AECOM believes that the Technical AQMP Objectives activity and the values will be compared to approve AQMP objectives remain relevant to the planned activities Memorandum short term action levels in order to assist site associated with the GMRP going forward. Section 3 managers in assessing or modifying site activities to prevent exceedances of project criteria. 2. To measure ambient air quality in the community surrounding the remediation sites to confirm that there are no significant impacts to community air quality as a result of remediation activity. An opportunity exists in the revision of the AQMP to correct this Technical Station Naming Change One community station – YCC – was erroneously named naming error, and through discussion with PSPC and CIRNAC it Memorandum – YCC when the monitoring program was established. has been decided that it be more appropriately named the Section 2 Yellowknife Bay Community Station, abbreviated by YKB. Appendix C - Analysis Of 2013-2017 Monitoring Data.Docx C-3 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Appendix C Document Item Current Status Recommended Change Reference Through discussion with PSPC and CIRNAC, it was Technical Station Naming Change The AQMP (AECOM, 2013) refers to the site perimeter decided to refer to these as “site perimeter” stations to Memorandum – Perimeter Stations stations as “fenceline” stations. avoid confusion with planned fencing that is expected to Section 3 enclose a smaller area within the site. For future consideration, AECOM recommends removing Technical Measured Parameters – Continuous basis reported as 15-minute averages: TSP, TSP monitoring requirements from the site perimeter Memorandum Site Perimeter Stations PM10 stations and maintaining only PM10 at these stations. Section 3.1.1 For future consideration, AECOM recommends removing PM2.5 monitoring requirements from the community stations and maintaining only PM10 at these stations. For future consideration, AECOM recommends removing Continuous basis reported as 15-minute averages: trace metals monitoring requirements from the . PM10, PM2.5 community monitoring stations. Discrete 24-hour samples: Technical Measured Parameters – . TSP plus Sb, Fe, Pb, Ni Memorandum Community Stations For future consideration, AECOM recommends only Section 3.1.2 . PM10 plus As collecting asbestos samples at the community stations when site activities involve a known disturbance of . Asbestos asbestos-containing material, such as a building demolition. Since arsenic pollution is a primary concern for the GMRP and the community, AECOM recommends retaining the requirement for metals analysis from the AQMP. Laboratory detection limits were evaluated to determine if Technical Laboratory Detection they were appropriate to allow for meaningful interpretation No changes are recommended. Memorandum Limits of measured concentrations. Section 3.1.3 Appendix C - Analysis Of 2013-2017 Monitoring Data.Docx C-4 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Appendix C Document Item Current Status Recommended Change Reference AECOM recommends updating the air quality criteria for PM2.5, Some air quality criteria have been updated since the AQMP and adding criteria for Ni, Pb, and Sb, and changing the air (AECOM, 2013) was finalized in 2013. The AQMP does not quality criteria for iron from metallic iron to ferrous oxide. Technical specify air quality criteria for Ni, Pb and Sb, which are Air Quality Criteria Memorandum monitored parameters. Additionally, the AQMP specifies an Additionally, AECOM recommends removing any air quality Section 3.2 air quality criteria for metallic iron, which is a form of iron that criteria for pollutants that are not being monitored and part of the is not expected to be produced from the GMRP activities. AQMP. AECOM does not recommend making such a change at this stage of the project. There is expected to be a reduced risk associated with the airborne concentration of metals resulting from planned remedial activities (as compared to the roaster deconstruction), as well as the elimination of an exposure pathway associated with re- The Risk-Based Action Level (RBAL) was developed for the routing the public-access roadway. However, there is value in Technical Review of RBAL roaster deconstruction and considered potential public maintaining an RBAL that is designed to protect human health Memorandum exposure associated with a roadway that crossed the Site. and reduce ecological risk even during the highest risk activities Section 3.3 of the project. Additionally, there is little advantage to relaxing the RBAL, since the RBAL has not been restrictive to site activities. Only a small number of concentrations were measured above the RBAL at the site perimeter, and none were measured above the RBAL at the community stations. Three exceedances of the RBAL were observed that were not attributable to increased particulate matter from wildfires. Technical Site Perimeter RBAL Consider early-season mitigation measures to reduce wind- Those exceedances were observed in May of 2014, 2015, Memorandum Exceedances blown dust from the south tailings pond. and 2016, and were attributed by the air quality contractor to Section 3.3 wind-blown dust from the south tailings pond. Appendix C - Analysis Of 2013-2017 Monitoring Data.Docx C-5 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Appendix C Document Item Current Status Recommended Change Reference While this approach was appropriate for the roaster deconstruction, it may not be suited for the variety of planned activities throughout the remediation phase. As the project Site Perimeter and continues, differentiating between remedial activities and site Community Stations: The AQMP (AECOM, 2013) was developed for the roaster Technical conditions may be appropriate. Monitoring program deconstruction, and recommends that monitoring occur Memorandum tailored to different consistently during remedial activities. Section 3.4 AECOM suggests a tiered monitoring approach based on the remedial activities characterization of the remedial activity occurring onsite, the level of contamination of material that may be disturbed, and environmental (seasonal) conditions at the time of the activity. AECOM recommends that the on-site meteorological station be Meteorological data collection on the Site appears to be inspected to determine the source of the bias, and whether systematically biased. This may lead to an incomplete repair or replacement of the station is required. Technical On-Site Meteorological understanding of wind speed and direction and how on site Memorandum Station activities relate to measured concentrations of monitored Additionally, AECOM recommends that a comparison of on-site Section 4.1 contaminants. meteorological data with airport data be performed with regular reporting to identify any potential bias between the two stations. Site perimeter Stations I and D have a significant overlap in terms of the portion of the airshed they are measuring. Comparing measurements between the two stations shows AECOM recommends considering the removal of Station D, that Station I (located at the top of the embankment) provided that Station I can fulfil the intent of site perimeter Site Perimeter Station captured a large number of events with PM10 concentrations monitoring (e.g. no remedial activities occur between the Technical Locations – Stations I & above baseline that were not measured by Station D locations of Station I and Station D). Memorandum D (located at the bottom of the embankment). Section 4.2.7.1 AECOM notes that the station may need to be relocated when Conversely, very few events of PM10 concentrations above the South Pond is incorporated into the Central/North ponds. baseline that were measured by Station D did not coincide with an event of PM10 concentrations above baseline measured by Station I. Appendix C - Analysis Of 2013-2017 Monitoring Data.Docx C-6 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Appendix C Document Item Current Status Recommended Change Reference AECOM recommends continuing the mitigation measures that Gusts and wind speed variation have a relatively small Technical have been applied to the project. impact on observed concentrations at the site perimeter and Memorandum community monitoring stations. Section 4.2.5 Gust and Windspeed The favourable monitoring results at higher wind speeds are Analysis likely a result of the increased application of dust suppression Higher wind speeds and gusts are often associated with Technical mitigation measures during periods of high wind speed, higher concentrations of particulate matter; however, this Memorandum effectively preventing increased dust concentrations during was not observed in the analyzed data. Section 5 those wind events. AECOM recommends an investigation into this bias by the air quality consultant to determine the cause of the bias (e.g. placement, technology difference, etc) and propose a plan to There appears to be a systematic bias between the co- correct the bias. located site perimeter (Station F) and community station Technical Measurement Bias – (Station YKB, formerly YCC) where the community station Memorandum Stations F & YKB Alternately, AECOM recommends considering the removal of consistently measures higher than the site perimeter station Section 4.2.7.2 the site perimeter station provided that reporting from the during periods of PM10 concentrations above baseline. community station can be adapted to fill the purpose of the site perimeter monitoring (e.g. reporting short-term concentration changes in real time) No changes recommended to windspeed threshold bins. Windspeed threshold bins in the Dust Management Plan Technical Mitigation Measures – (Draft) (CIRNAC, 2018) were considered with respect to the AECOM recommends specifying the required mitigation Memorandum Wind Speed observed wind speeds and associated measured dust measures in further detail or referring to the Dust Suppression 4.2.6 concentrations. and Mitigation section of the DMP where appropriate when specifying responses to windspeed thresholds. Technical Mitigation Measures – Responses to visual dust observations are specified in the No changes are recommended to the visual dust monitoring Memorandum Visual Observations Dust Management Plan (Draft) (CIRNAC, 2018). requirements of the DMP. 4.2.6 Appendix C - Analysis Of 2013-2017 Monitoring Data.Docx C-7 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Appendix C The following figures provide a summary of the key analyses of the previous air quality data as presented in the AECOM technical memorandum. Note that the figure numbers are those direct from the AECOM technical memorandum. . AECOM recommended that there is little advantage to changing the RBAL, since only a small number of concentrations were measured above the RBAL at site perimeter locations outside of specified wildfire dates, as shown in Technical Memorandum Figure 2. 0 C") 20 -IJ) E C ,Q rn::::,_ ro en ~ Q) '°~ IJ) I\ 15 .0 C 0 ,Q .EC ~ 'E .;, Q) u 10 C 0~u 0 Q) 0 .0 - E~ ::, c.. z 5 0 ,t:- ('~ 0'<2 /'& -S'~ ~~ ~\, ~ Q,'1-: ,s,~ 0-?; I!> 01:j o'i-_, ;;,('~ ,,.0,,. ;;,_,,; C!>u' 0-?; o<-0 ~Its ;;, ,.,<) ~Its ,<) @u',, C!>u' o_,O" ,.,<) o-,0' o_,o- Figure 2. Number of 15-min PM10 Measurements above the Risk Based Action Level at Site Perimeter Stations . AECOM recommends that a comparison of on-site measurements of wind speed and direction with the airport data be performed with regular reporting to identify any potential bias between the two stations. It was noticed that for winds blowing from the north, current data from the onsite met station show a consistent absence of measurements as shown in Technical Memorandum Figure 4. 9% N 6% 8% -10I05" 7% 5% 6% 5% 31 7!040 20510 317 w E w 13 1020 5 7 6 io 13 1 81076 (km/hr) Figure 4. Wind Rose Plots from On-site (Left) and Yellowknife Airport (Right) Meteorological Stations (2013 – 2017) Appendix C - Analysis Of 2013-2017 Monitoring Data.Docx C-8 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Appendix C . At the site perimeter locations, TSP and PM10 are measured concurrently, and data trends were observed to be consistent between the two fractions of particulate matter, as shown in Technical Memorandum Figure 7. AECOM recommends considering the removal of TSP monitors from the sire perimeter locations in the future. The TSP data collected at the site perimeter stations is not providing additional information about risks from project-based activities to human health or environmental health. ■ A-North • B-Town • C-NorthWest • D-Beach ♦ E-A1C1 ◄ F-Marina ► G-West • H-NorthWest Pond * I-South Pond • 2000 ...--.. I (") E * --0) * 3 ■ 1500 en C 0 :;:::; ,_ro 1000 c Q) (.) C 0 500 U a.. (/) l- o 1000 (") -E ♦ --0) 3 800 I en C 0 :;:::; 600 ,_ro .. C • -Q) (.) 400 C u0 0 200 •• ~ • ~ a.. 0 6/1/2013 7/26/2014 9/19/2015 11/12/2016 Figure 7. TSP and PM10 Concentrations Measured at Site Perimeter Stations . AECOM recommends continuing with the dust suppression techniques that have previously been employed, as they appear to be effective in preventing elevated concentrations of PM10 at higher wind speeds. Since the site perimeter stations only measured a very small number of instances where concentrations were above the RBAL. Furthermore, since the community stations did not measure any such exceedances, extending dust suppression practices to lower wind speeds when there are no specific site activities going on, as outlined in the Dust Management Plan, is considered optional. Appendix C - Analysis Of 2013-2017 Monitoring Data.Docx C-9 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Appendix C ;,"600 ;,"600 ;:;'600 E E E c,500 A-North c,500 8-Town c, 500 C-NorthWest :i 1 :i --;;;400 ';;' 400 ~ 400 0 C: 0 C: 0 C: ~ g 300 ~ g 300 ~ g 300 a.. ., a.. ., a.. ., ~., 200 ~., 200 E., 200 g 100 g 100 g 100 'A. ~ 0 ....,_,.,_ 0 0 u 0 - u u 0 0 10 20 30 40 50 60 0 10 20 30 40 50 60 0 10 20 30 40 50 60 Wind Speed (km/hr) Wind Speed (km/hr) Wind Speed (km/hr) ;:;'600 r,'600 ;:;"600 E E E 0)500 D-Beach c,500 E-A1C1 cn soo F-Marina :i 1 ';; 400 -; 400 -;;;400 0 C: 0 C: 0 C: ~ g 300 ~ g 300 ~ g 300 a.. ., a.. ., a.. ., °E., 200 °E., 200 E., 200 g 100 g 100 g 100 0 0 0 u 0 u 0 u 0 0 10 20 30 40 50 60 0 10 20 30 40 50 60 0 10 20 30 40 50 60 Wind Speed (km/hr) Wind Speed (km/hr) Wind Speed (km/hr) ;,,600 ;,-600 ;:;--600 E E E c,500 G-West c,500 H-NorthWest Pond c,500 I-South Pond :i 1 1 ';;; 400 ';;; 400 '";;; 400 0 C: 0 C: 0 C: ~ g 300 ~ g 300 ~ g 300 a.. ., a.. ., a.. ., ~., 200 E., 200 °E., 200 g 100 g 100 ., g 100 0 0 " 0 u 0 u 0 ~ u 0 0 10 20 30 40 50 60 0 10 20 30 40 50 60 0 10 20 30 40 50 60 Wind Speed (km/hr) Wind Speed (km/hr) Wind Speed (km/hr) Figure 31. PM10 Concentrations at Different Wind Speed Measured at Site Perimeter Stations ;, 600 -~~~-.-~--.~~~r---,r-.--.. E c,500 NOL :i "";; 400 0 C: ~ g 300 X a.. ., ~., 200 g 100 0 U 0 0 10 20 30 40 50 60 0 10 20 30 40 50 60 0 10 20 30 40 50 60 Wind Speed (km/hr) Wind Speed (km/hr) Wind Speed (km/hr) Figure 32. PM10 Concentrations at Different Wind Speed Measured at Community Stations Appendix C - Analysis Of 2013-2017 Monitoring Data.Docx C-10 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Appendix C . No correlation was found between the arsenic and PM10 concentration. As such, AECOM recommends continuing to monitor for trace compounds including arsenic. This is a valuable method to confirm the RBAL and verify the potential for arsenic exposure throughout the varying Site activities and the disturbance of different areas of the Site. Additionally, during periods of elevated background levels due to wildfires, the arsenic analysis provides confidence that PM10 concentrations above baseline measurements are not related to activities on the Site. 1111 NAPS 400 EZ23 NDL ~ YKB t--- 300 ~ NVN T""" 0 N I ('I") 60 T""" 0 N 50 CJ') >-ro 0 40 -0 a5 30 ..c E z::J 20 10 Non-detect <1% 1%-2% 2-5% 5-10% 10-31% >31% Percentage of Ambient Air Quality Criteria (0.3µg/m3) Figure 42. Arsenic Measurement Results Summary . For the analysis of asbestos, all available data from the community stations was plotted with PM10 when wind was blowing from the site. All of the asbestos readings are well below the AAQC. Similar to the analysis of arsenic measurements, no correlation noted between asbestos and PM10 concentration. Appendix C - Analysis Of 2013-2017 Monitoring Data.Docx C-11 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Appendix C E I • NOL • YKB • NVN I --....Cl) Q) .0 0.04 ~ MOC Cl) C 0.03 0 • ~ 0.02 "E Q) u 0.01 C • 0 0 ,-.. Cl) (") •;,; a. • . J ■ Ti 5 I a 0.00 .. 0 E Cl) --C> 1000 -Q) ::l .0 Cl) -Cl) 800 I <( C 0 :;:; • ....ro 600 C 400 -Q) u C 0 200 RBAL 0 0 0 ~ ~ a.. 6/1/2013 8/5/2014 10/9/2015 12/12/2016 Figure 48. Measured Concentrations of Asbestos at Community Stations and PM10 Concentrations when Wind Blowing from the Site . For the analysis of metals, all available data from the community stations was plotted with PM10 when wind was blowing from the site. Concentrations of all metals were well below the applicable AAQC. In the event that iron concentration was above AAQC, PM10 concentration was also found above the baseline. Appendix C - Analysis Of 2013-2017 Monitoring Data.Docx C-12 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Appendix C ,..-... C") ... E I • NDL • YKB NVN I --Ol AAQC 25 3 C/l C ~ 20 0 :.;::. cc ~ 15 ... C -Q) 10 (..) C 0 ~ 5 0 >. ,..-... C C") 0 0 E 25 •• •• E 0) - AAQC - ~ --:::l 20 <( -C/l C 0 :.;::. 15 cc... C 10 -Q) (..) C 0 5 0 ,..-... C") C 0 E ...0 0.5 --0) AAQC :::l 0.4 -C/l C 0 :.;::. 0.3 cc... c 0.2 Q) • (..) C 0.1 0 ,..-... 0 C") E ..... 0.0 i:::, •• cc _ Q) Ol 0.20 -- ··-- AAQC ...J 3 C/l C 0.15 0 ~... 0.10 ~ C -Q) (..) C 0 0.05 ~ 0 ,..-... Q) ,. C") .::,,:. 0.00 • ... .. •• .. E -~ 1000 0) z --:::l I 800 -C/l C 0 • :.;::. 600 ...cc 400 C -Q) (..) C RBAL 200 0 0 0 0 ~ ~ 6/1/2013 8/5/2014 10/9/2015 12/12/2016 a.. Figure 49. Measured Concentrations of Metals at Community Stations and PM10 Concentrations when Wind Blowing from the Site Appendix C - Analysis Of 2013-2017 Monitoring Data.Docx C-13 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Appendix C C1.2 Summary of Wind Data Wind contributes to the dispersion, re-suspension and surface drying through evaporation; all of which have the potential to release the dust particles. As such, wind conditions are very important in understanding the potential distribution of airborne contaminants throughout the Remediation Program. Wind roses are a convenient and efficient method to present wind data. As such, wind roses are used to present the measured total wind speed, wind direction and wind class frequency data for local wind patterns. The wind roses in this section will aid in the analysis of the wind behaviour and lead to the determination of monitoring locations that are required for the AQMP. The study area includes two monitoring stations that were used in this assessment: . Yellowknife Airport (NavCanada), located southwest of the Giant Mine site . Giant Mine Site (CIRNAC) The meteorological station located at the Giant Mine Site showed a systemic bias throughout the monitoring period from 2013-2017, as noted in Giant Mine Air Quality Monitoring Program Re-Evaluation technical memorandum (AECOM, 2018). Meteorological measurements from this station do not include measurements of wind events blowing from the North. Wind roses from these stations are included below, but should be considered in this context. Figure 3-1 and Figure 3-2 depict the wind roses for the local study area. In the wind roses below, the length of radial barbs depict the total percent frequency of winds from the indicated direction, while portions of the barbs of different colours and widths illustrate the frequency of associated wind speed categories. The frequency distribution for wind speeds for the local study area is illustrated below each wind rose in Figure C-1 and Figure C-2. Figure C-1 illustrates the data from the Giant Mine site while Figure C-2 represents Yellowknife airport data. The seasonal wind roses allow for a more detailed look at the wind data through the seasons within the five-year period. During the more active remediation period (April to November), the Giant Mine site shows that the most frequent wind strength is generally between 2.10 to 3.60 m/s. The prevailing wind originates from the south, but there is good distribution of winds from the north as well. From the Yellowknife airport meteorological station, the most frequent wind strength is also between 2.10 to 3.60 m/s during construction period. Again, the prevailing wind originates from the south, with good distribution of winds from the north as well. Detailed analysis is provided for the Giant Mine Site meteorological station through the rest of this section. The winter wind rose shows that the prevailing winds were from the northwest and the east, which also concurs with the 30-year climate normal for that period. The average winter wind speed is 2.35 m/s with 12.74% calms. The fall data shows generally the same shape as the five-year wind rose with the exception that the highest wind speed seen through the seasons was encountered in the fall months from the west northwesterly direction, and is consistent with the historical assessment information. In the fall, the average wind speed is 3.25 m/s with 3.98% calms. Spring data illustrates that the predominant winds were easterly with some northeast and some southwest winds. In the spring, the average wind speed is 3.26 m/s with 4.29% calms. The frequency distribution of wind speeds shows that spring and fall have the highest average wind speeds. Appendix C - Analysis Of 2013-2017 Monitoring Data.Docx C-14 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Appendix C For the summer periods, the prevailing winds are from the south and south west followed by the constant easterly wind. The average wind speed is 3.21 m/s, the lowest average wind speed of all seasons. Calms occur 4.20% of the time. Appendix C - Analysis Of 2013-2017 Monitoring Data.Docx C-15 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Appendix C Figure C-1: Wind Roses for Giant Mine Site (2013-2017) _.. •·· · ···-. / ..--· ···· ; .... .-·· ··· ..·· ··•,.. r··- ·--. ·.. \ : ~:· / / / ! ./ •, i ,... , '·. . ··.. _ --r::J ,-1114 \. - IJO 111~ • •' .... - •«i-H;,~~-·· . 2.t~HO D O u,.110 ·· ---·! ···· ·•···••' .-·· ' _ •••« .... JS(l,tl'H·•·"· .... Giant Mine Site Total Wind Rose Wind Class Frequency Distribution 35 EL 30 26.8 ~ 25 -- % 20 = -- 15 -- 10 - - .12. - -- 0 2 0,0 0 ' ' Calms 2.10- 3.60 tO5.70- 8.80 8.80- 11:0 c,; 11.10 0.50 - 2.10 3.60 - 5.70 Wind Class (mis) Frequency Distribution – Giant Mine Site Appendix C - Analysis Of 2013-2017 Monitoring Data.Docx C-16 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Appendix C ······ ···1mii .. . ·-·-·1mi···--...... _ .•··· -- . t. ,... -+-' ·-·-··· ····-.. ,• .. , ..-···· :········· .. ; i--··· iMn ·~ ...... l""~' !·•·-~ ----~-·-- . \ .. Wtf;t$ft(p \ .. ··t ... W'II0"'8!D \ \ / ____ ,,. 19'""' ..... o \ _/ ""' a u1,10 □ -""' , _ ... • ~1" -•tt: \ ... • ,v~ ,~ . ,4',l,,. • .t6)-~,0 Oi•i •• 0 1~•Hlo,l ····-. .... -·-· □ "~ -i,, □ •~ 1 » ······· ...~ ...... ,.-· ~-.i1.-.. c-•:rr.- ·-.. ·-..._ ... , l,SWT>I ·• ..... Wind Rose – Giant Mine Site Winter (November - March) (2013-2017) Wind Rose – Giant Mine Site Spring (April-May) (2013-2017) Wind Class Frequency Distribution Wind Class Frequency Distribution 40 40 35 33.1 ~ 35 30 - 30 25 - 25 % 20 % - 20 .1L1 15 - J11. - 15 10 I- - - - 10 5 - - -- 5 02 00 04 00 0 ....j.., ~ 0 Calms 0.50-2,10- 2.10-3.60 -3.60-5,70TI 5,70-8.80 8.80-11.10 '>=11.10 Calms 0.50 - 2.10 2.10- 3.60 3.60 - 5-70 5.70 - 8.80 8.80 - 11.10 >= 11.10 Wind Class (mis) Wind Class (mis) Frequency Distribution – Giant Mine Site Winter (November-March) (2013-2017) Frequency Distribution – Giant Mine Site Spring (April-May) (2013-2017) Appendix C - Analysis Of 2013-2017 Monitoring Data.Docx C-17 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Appendix C ·····-. -·-····:···· +.... ··-... ·,,_ ·,. .. , .. ·•' .. ·-..... ,· •• --·····•i ' ··••··•• "' _ ...... •·· ·.. / \~~ ...... i · •· ··. . _..,. ,... , CJ """ □ -1!') - t«I.IIIO ·--.. _ .. \ . -. •, • ,10.,g. ·• : .. .- ,l'Q,~·~ ••it - lt0t'!I ...... ,.·· _./ . ,oo,,oe ·-... D o11u~ □ : 1, .)~ O ,,;,.:,r ··-. -..... _ ··--. □ ·~ ,,~ _.,•· -;- . '-'"' ·• ... __. ..--- .,•· ,..,,,. .,•· --····· Wind Rose – Giant Mine Site Summer (June-August) (2013-2017) Wind Rose – Giant Mine Site Fall (September-October) (2013-2017) Wind Class Frequency Distribution Wind Class Frequency Distribution 40 40 35 35 30 30 25 25 % % 20 20 15 15 10 10 5 5 0 1 00 04 0 0 0 0 Calms 0.50 • 2.10 2.10-3.60 3.60-5.70 5.70-8.80 8.80-11.10 >= 11.10 Calms 0.50 · 2.1 0 2.10-3.60 3.60-5.70 5.70-8.80 8.80-11.10 >= 11.10 Wind Class (mis) Wind Class (mis) Frequency Distribution – Giant Mine Site Summer (June-August) (2013-2017) Frequency Distribution – Giant Mine Site Fall (September-October) (2013-2017) Appendix C - Analysis Of 2013-2017 Monitoring Data.Docx C-18 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Appendix C Figure C-2: Wind Roses for Yellowknife Airport (2008-2013) ...,_,.. .. £!) _,, • . .... , 1111 • 110 - 1.IO - 11111 -111 o0 ....H 0 .,11" .. Yellowknife Airport Total Wind Rose W ind Class Frequency Distribution 40 I- 35.0 35 30 -=-- 25 I- % 20 I- 17.6 15.0 - 15 - I- I- 10 - I- I- 5 - - I- 1.6 1.8 0,3 0 - I - ..... -I-= --4-- - I - Calms 0.50 - 2.10- 2.10 - 3.60- 3.60 - 5.70- 5.70 - 8.80 8.80 - 11 .10 >= 11 .10 Wind Class (mis) Yellowknife Airport Total Frequency Distribution Appendix C - Analysis Of 2013-2017 Monitoring Data.Docx C-19 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Appendix C ••••••.. • ·· ··• ,lolOIITM. ··.,..,:··· ·,._ ! / I - ··· ;wrsr ;- ! \ ;: \_ \ •, \ ··.. \_ WICI Si'EEO ~vuo ... ···-~·- '"'" \ Cl _,. .. / £:1 ...... - ·· . .... 1110 - ! Ill-UC -..,,, ...... · 1--HII .. • •••n ' •·•. .. D ,-.,. Q . .a.uo O H11no ~· □,_,,-..... i ,. .. --···•'·· Wind Rose – Yellowknife Airport Winter (November - March) (2013-2017) Wind Rose – Yellowknife Airport Spring (April-May) (2013-2017) Wind Class Frequency Distribution W ind Class Frequency Distribution 40 45 on 1 35 34,7 40 ~ - 31,7 35 30 - 30 25 2A-.6 - % 25 - - 22.0 % 20 f- = .11.L 20 - - - 15 - - E.1. 15 - 10.8 -- 10 '- -- 10 -, - - 5 2.8 ------2.3 - - - 1.4 06 -- -- 06 0,2 I I 0 ' - - 0 ~ ' 0.5*10 - 2.1o"!";'60- 3.67s.10 8.80-11.10 >= 11 .10 Calms 0.50 - 2.10 2.10-3.60 3.60-5,70 5.70---+-8.80 8--.80- 11.10 >= 11 .10 5.70 - 8.80 -- ~ Wind Class (mis-) Wind Class (mis) Frequency Distribution – Yellowknife Airport Winter (November - March) (2013- Frequency Distribution – Yellowknife Airport (April-May) (2013-2017) 2017) Appendix C - Analysis Of 2013-2017 Monitoring Data.Docx C-20 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Appendix C .,·•·.. -~. ·1~····· ·········· ···~ ···· ... ····· ~ ··t· ··:······· ···•. ···-. ····1····- ...... ·•.. ·-..... -~ ·. , \ ...... ' \ ),...... f...... )_·...... • ...... 1 jW!$T ""'' ·, , ·, '• / / •, ...... '• _,..,., IM I ,... , o ...... ,. '•·... (0 ""'"..a • non• - •to-Ill) . )l'Q, t t:> .. ·· -r ··--· ...., . !lll•tlC - ltof"} __ ,,.· - l(li:l•~"I 0 !.~-HO 0,19111: □ •t:in) ··.. ,_ ·-... O o)n-,•~ ·•,.. e..-,,.,o,~...... ·r .... _,,•· ···• .. ··; ..... _ ..•· ;&,Ot/rtj ' ·•...... , ...... ·...... \'-01)111 ... ····· · Wind Rose – Yellowknife Airport Summer (June-August) (2013-2017) Wind Rose– Yellowknife Airport Fall (September-October) (2013-2017) Wind Class Frequency Distribution Wind Class Frequency Distribution 40 40 35 35 ~ ~ 30 30 27.8 26.7 25 >- 25 - .E,.'.!. % 20 " - 19.9 % 20 - - 15.8 - - 15 ,- 15 12.9 - - ~ 10 - - - 10 - - - 5 -- 5 - - 1.6 - 2.4 0.8 - 0.7 02 0,2 0 ' I - 0 ' I I Calms 0.50 - 2.10 2.10 - 3.60 3.60 - 5.70 5.70 - 8.80 8-.80 - 11.10 > = 11.10 Calms 0.50+ - 2. 10 2.10 -3.60 3.60-5.70 5.70-8.80 ~8.80 - 11.10 ~= 11.10 Wind Class (mis) Wind Class (m/s} Frequency Distribution – Yellowknife Airport Summer (June-August) (2013- Frequency Distribution – Yellowknife Airport Fall (September) (2013-2017) 2017) Appendix C - Analysis Of 2013-2017 Monitoring Data.Docx C-21 Imagine it. AECOM Delivered. Appendix D Historical Ambient Air Monitoring AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Appendix D CIRNAC conducted ambient air monitoring during the summer months for eight years from 2005 to 2012. The on- site historical ambient air monitoring program was implemented to obtain information for fugitive emissions from tailing areas and other disturbed areas in the Giant Mine site. It was designed to establish information to compare with the effect of future remediation activities and was not used for mitigative purposes. The intent was also to augment off-site measurements of particulate matter concentrations. Simultaneous samples of particulate matter (TSP and PM10) was collected to determine the ratio of the two size fractions, and to ensure that an adequate mass of particulates was collected for trace element analysis. Air monitoring was conducted at four locations on the Giant Mine site and one location on the Giant Mine town site. The equipment consisted of eight Mini-Vols and one Hi-Vol. The historic on-site monitoring program spanned from 2005 to 2012 during July to September. The ambient air monitoring program included the following parameters: . PM10 . TSP Additionally, the particulate samples were analyzed for inorganic trace element concentrations, including arsenic. Sampling was conducted on a 24-hour, 6 day cycle. D1.1 Historical Air Monitoring Results SENES evaluated the historical air monitoring program results, which was further summarized by AECOM as outlined in Table 6-1. Table 6-2 shows the average values of the statistical parameters for the 8 monitoring periods. The past monitoring reports report that iron (Fe) and arsenic exceeded the air quality limits. The breakdown by location and by year can be seen in Table D-1 while the average summary of the data by location for the 8 year period can be seen in Table D-2.The mean concentration for TSP exceeded the criterion in the northwest pond, while the mean PM10 concentration illustrated exceedances at all monitoring locations (air quality criteria used in the studies) (SENES, 2005-2013)). The average (over 2005-2012) number of valid data points per location per monitoring period ranged from 9 to 12. Overall (2005-2012) air monitoring results are outlined in Appendix D; locations of monitoring stations are also in Appendix A. Table D-1. Summary of Statistics for Historical Ambient Air Monitoring Data (2005 – 2012) Giant Mine Northwest South Pond B3 Pit Mill Town Site Pond Average Maximum 32.36 161.16 196.29 183.10 315.66 Average 25.12 174.52 196.18 179.58 302.78 TSP 95th percentile (µg/m3) Average Mean 13.52 95.93 101.43 101.32 135.33 Range of Exceedance Occurrences 0 0 - 6 0 - 8 0 - 10 0 - 9 Average Valid Data points* 12 12 11 11 11 As in TSP Average Maximum 0.023 0.252 0.147 0.091 0.727 3 (µg/m ) Average 0.016 0.199 0.132 0.081 0.541 Appendix D - Historical Ambient Air Monitoring.Docx D-1 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Appendix D Giant Mine Northwest South Pond B3 Pit Mill Town Site Pond 95th percentile Average Mean 0.005 0.064 0.040 0.034 0.176 Range of Exceedance Occurrences 0 0 - 2 0 - 1 0 0 - 4 Average Valid Data points 12 11 11 11 10 Average Maximum n/a 126.96 132.54 131.30 134.18 Average n/a 132.77 134.23 135.70 137.50 95th percentile PM10 (µg/m3) Average Mean n/a 81.44 78.46 88.80 83.53 Range of Exceedance Occurrences n/a 2 -12 1 - 12 1 - 13 0 - 11 Average Valid Data points n/a 11 12 9 12 Average Maximum n/a 0.093 0.045 0.029 0.155 Average n/a 0.065 0.042 0.027 0.127 95th percentile As in PM10 (µg/m3) Average Mean n/a 0.027 0.018 0.016 0.062 Range of Exceedance Occurrences n/a 0 - 1 0.00 0.00 0.00 Average Valid Data points n/a 10 11 9 11 Exceedances from Ontario Ambient Air Quality Criteria were noted for both TSP and PM10. The Northwest Pond resulted in higher readings of TSP and arsenic. In addition, the Northwest Pond had the most exceedances for both TSP and arsenic. The Giant Mine Town Site resulted in lower readings for both TSP and arsenic when compared to the other sites. PM10 was found to be similar at all monitoring locations on the Project site. The particulate samples were also analyzed for inorganic trace element concentrations. All metal concentrations were found to be below the applicable air monitoring criteria with the exception of Fe and arsenic (SENES, 2005- 2013). The arsenic concentrations in TSP and PM10 exceeded the allowable 24-hour criteria, as seen in Table 3-2. At the time of this report, no quantitative data for Fe levels was available for further statistical analysis. This study is not representative of a baseline since the number of valid data points for each annual monitoring period is low, monitoring data is limited to three months a year (July to September), and the locations and equipment chosen are not consistent with the Project; however, used in conjunction with the other historical reports analyzed, the historical air monitoring program provides a basis for selecting monitoring criteria. These reports include, but are not limited to: . The CALPUFF air dispersion modelling for the giant mine remediation project (SENES, 2012) . Giant Mine Remediation Plan (SRK Consulting, 2007). D1.2 Historical National Ambient Pollution Schedule (NAPS) Monitoring Data for the Community In addition to the on-site historical data, air monitoring data previously collected in the Yellowknife community was also analyzed. Air monitoring data was collected at two stations in Yellowknife: Yellowknife station (ID: 129003); Appendix D - Historical Ambient Air Monitoring.Docx D-2 AECOM Public Services and Procurement Canada Giant Mine Remediation Project – Air Quality Monitoring Plan Appendix D and the Yellowknife Post Office station (ID: 129001). Please refer to Appendix A for the locations of the air monitoring stations. The monitoring data was gathered in partnership with NAPS. In 2006, Hi-Vol monitoring (for particulate matter and inorganic trace elements) at the Post Office was removed from operation. Data for SO2, NO2, PM2.5, PM10, and arsenic air monitoring was obtained from GNWT. The monitoring data for Fe was obtained from Environment Canada. Statistical analysis was completed by AECOM for all data provided. The air monitoring results were compared to the relevant air quality criteria (Table 4-2) and the results are summarized in Table D-2. There is a low frequency of exceedances for all parameters. Exceedances occurred for PM2.5 and PM10, at 1% and 2%, respectively. Table D-2. Summary of Statistics for Yellowknife-NAPS Ambient Air Monitoring Data (2005 – 2011) Yellowknife Station Yellowknife Station Post Office Station Yellowknife Station (2005-2011) (2005-2006) (2004-2005) (2000-2004) SO2 NO2 PM2.5 PM10 As As Fe Minimum (μg/m3) 0 0 0 0.1 0 0 0.00 Maximum (μg/m3) 0.0040 0.0235 110.6 170.4 0.0394 0.0409 5.06 Average (μg/m3) 0.0006 0.0031 3.7 13.2 0.0025 0.0033 0.24 Exceedances 0 0 17 42 0 0 1 Exceedances [%] 0% 0% 1% 2% 0% 0% 0% Valid Data points 2,459 2,493 2,444 1,753 110 105 682 Valid Data per 96% 98% 96% 69% 94% 91% 94% Total days [%] Standard Deviation 0.0007 0.0029 5.0695 13.1685 0.0049 0.0064 0.5071 Appendix D - Historical Ambient Air Monitoring.Docx D-3 Imagine it. AECOM Delivered. Appendix E Monitoring Requirements Decision Tree Minimal Activity onsite / Care & Maintenance: · Activity onsite that is non-intrusive (e.g., site inspections, equipment or supply delivery/placement) · Snow clearing with frozen or wet ground AQM 0 · Activity onsite that involves isolated instances of minor ground disturbance that are unlikely to provide the opportunity for significant entrainment of dust such (e.g., soil sampling program using hand trowels) Yes Snow cover or Activity onsite that involves minor handling/moving/disturbing soil or waste including Hotspot*? No frozen ground/ No test-pitting AQM I material? Yes Yes Activity onsite that involves moderate/major ground disturbance, earthworks: · Excavation of tailings · Earthworks Snow cover or · Drilling Hotspot*? No frozen ground/ No AQM II material? · Blasting and Quarrying · Crushing · Major road works Yes No Activity onsite that involves Building demolition and consolidation of wastes: · The disturbance of friable materials Friable Asbestos? Yes AQM III · Waste material handling *Hotspots are determined by most up-to-date soils heat map available. Figure 3. Air Quality Monitoring Level Decision Tree Level O: light breeze and no Apply appropriate mitigation. Yes---.i Basic BMP's apply14-----, activities likely to generate dust Level 1 No Is the activity on a Increase water or suppressant No hot spot area? and apply appropriate mitigation. Level 2 Level 1: One exceedance at Which Wind Speed Yes Activity-Specific Level? Yes Monitors No Work is limited to mitigation and low-dust generating Level 3, 4 activities. Work can resume once wind levels decrease or exceedance values drop. No No Is the activity on a Increase water or suppressant No hot spot area? and apply appropriate mitigation. Level 2: Is the ~L___- One RBAL exceedance measurement down Is it Level 4 wind Yes Yes at Site Perimeter wind of site speed Monitors activities? Yes No Work is limited to mitigation and low-dust generating Yes activities. Work can resume once wind levels decrease or exceedance values drop. Level 3: Is the RBAL exceedance at measurement down Work is limited to mitigation and Yes Yes two or more Site wind of site --i► L___1low-dust- generating activities erimeter Monito activities? No Level 4: Work is limited to mitigation and RBAL exceedance at Yes low-dust generating activities Community Station Figure 51. Recommended Response to Real Time Air Quality Monitoring aecom.com
GIANT MINE REMEDIATION PROJECT Dust Management and Monitoring Plan
