Con Mine Meg Keg Peg Lake System Study Design Workshop #1 December - - PowerPoint PPT Presentation

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Con Mine Meg Keg Peg Lake System Study Design Workshop #1 December - - PowerPoint PPT Presentation

Con Mine Meg Keg Peg Lake System Study Design Workshop #1 December 10, 2019 Newmont Goldcorp Confidential I Presentation Name 1 Month YEAR Meg Lake, looking towards Keg Lake, 2017 Workshop Agenda Welcome and Introductions MNML


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SLIDE 1

Month YEAR Newmont Goldcorp – Confidential I Presentation Name 1

Con Mine Meg Keg Peg Lake System Study Design Workshop #1

December 10, 2019

Meg Lake, looking towards Keg Lake, 2017

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SLIDE 2
  • Welcome and Introductions – MNML and Attendees
  • Background of Meg Peg Keg (MKP) lakes system - MNML
  • Goals and Objectives of the MKP Study – MNML and Attendees
  • Information Requirements to Meet Goals and Objectives – MNML and

Attendees

  • Summary and Wrap-up – MNML

Workshop Agenda

Keg Lake looking towards Con Mine, 2015

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SLIDE 3

Purpose of Workshop

  • Why is MNML completing a study on

Meg, Keg and Peg lakes and hosting this workshop?

  • See Schedule 6 Water Licence

Round Table of Introductions

  • What is your background with Con

Mine and/or MKP lake system?

  • What do you want to get out of or

contribute to this workshop?

Welcome and Introductions

Peg Lake, looking towards YK Bay, 2017

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Month YEAR Newmont Goldcorp – Confidential I Presentation Name 4

Description of Meg Keg Peg Lakes System

Meg Lake with approaching storm, 2019

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Sample Sample Sample

Characteristics of Meg, Keg, and Peg Lakes

  • Shallow (0.3 to 1 m) and relatively small lakes (0.07 to 0.38 km2)
  • Local climate, precipitation, and beaver activity affect the water volumes, elevations and

water quality in the lakes

  • Former beaver dam at outlet of Keg, and dam present at outlet of Peg; narrow, marshy

channels in between the lakes

  • Retention time through the system was modelled to be approximately 70 to 200 days,

depending on hydrologic conditions

Meg Lake, 2015 Meg Lake, 2017

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SLIDE 6

MKP Characteristics – Additional Details

Watershed Lake Surface Area (km2) Average Lake Depth(a) (m) Local Drainage Area Cumulative Drainage Area (km2) Total Land Area (km2) Total Water Area (km2) Total Watershed Area (km2)

Meg Lake Watershed

0.1 0.3 0.6 0.1 0.6 0.6

Keg Lake Watershed

0.4 1.0 2.2 0.5 2.7 3.3

Peg Lake Watershed

0.1 0.8 1.3 0.1 1.4 4.8

Peg Lake Outfall

not applicable not applicable 0.4 <0.1 0.4 5.2

(a) Measured during 2009 survey (Golder 2010) Local watershed boundaries, drainage areas, flow paths and flow connectivity within the MKP lake system were derived from publicly available elevation contour data using GIS tools (GNWT 2014). Due to the coarse resolution (2 m) of the elevation data, the assessment results have a correspondingly reduced accuracy.

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Historical Studies and Modelling

Historical Studies

  • Algal and invertebrate communities in three subarctic lakes receiving mine wastes (Moore et al.

1979)

  • Arsenic transport through the MKP lakes system (Bright et al. 1994, 1996)
  • Characterization of Arsenic in the effluent drainage basin of Miramar Con Mine, Yellowknife, NWT

(William Coedy, 1994) Modelling

  • 2010, 2018 GoldSim for the MKP lakes system and CORMIX modelling to estimate plume

dispersion in Jackfish Bay

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Environmental Monitoring

Surveillance Network Program (Water Licence) Metal and Diamond Mining Regulations (MDMER/EEM) Aquatic Effects Monitoring Program (Downstream) Supplemental Monitoring for the MKP Study

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Water Quality within MKP Lakes System

Above CCME aquatic life guidelines for some parameters (Phase 6 EEM Study)

  • Above chronic CCME aquatic life guidelines for chloride and some metals (e.g., aluminum,

arsenic, copper, iron)

  • Above acute CCME aquatic life guideline for chloride but typically below site-specific acute

lethality threshold (2,500 mg/L)

  • Within CCME pH guideline range and above CCME DO guideline

Peg Lake outflow into Jackfish Bay, 2017

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Water Quality within MKP Lakes System

Variable trends and patterns

  • Decreases in some parameters (e.g., chloride and ammonia) relative to 2000 to

2004 data

  • Variable seasonal and spatial patterns such as:
  • Concentrations of some parameters decrease with distance through the MKP

but some increase (e.g., chloride, arsenic) but not at a consistent location depending on the season or year

  • Seasonal trends for increasing concentrations during the open-water season

for TDS and major ions

  • Concentrations of some parameters are lower in the discharge than in the

receiving water at Meg and Keg lakes (e.g., arsenic, copper)

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Temporal and Spatial Trends - Chloride, 2000 to 2019

2000 4000 6000 8000

Average Chloride Concentration (mg/L)

Site

2000-2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 (draft)

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Temporal and Spatial Trends - Arsenic, 2000 to 2019

  • 0.2

0.2 0.4 0.6 0.8

Average Total Arsenic Concentration (mg/L)

Site

2000-2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 (draft)

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SLIDE 13

Current Water Quality - Chloride, 2019 (draft)

200 400 600 800 1000 1200 1400 1600 1800 2000

Chloride Concentration (mg/L)

Site

May-19 Jun-19 Jul-19 Aug-19 Sep-19

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Current Water Quality - Arsenic, 2019 (draft)

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

Total Arsenic Concentration (mg/L)

Site

May-19 Jun-19 Jul-19 Aug-19 Sep-19

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Month YEAR Newmont Goldcorp – Confidential I Presentation Name 15

Factors Influencing Meg, Keg, Peg Lakes

Climate – drought to record rainfall event

  • Historic Regional Operations
  • Future Operations / Land and water

use by others (off MNML lease)

  • Current treated effluent
  • Beaver Dams
  • Climate

Outlet of Meg Lake showing old flood damage to spruce trees

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References

Bright, DA, Coedy, B, Dushenko, WT, Reimer, KJ. 1994. Arsenic Transport in a watershed receiving gold mine effluent near Yellowknife, Northwest Territories, Canada. The Science of the Total Environment. Vol 155, pp 237-252. Bright, DA, Dodd, M, Reimer, KJ. 1996. Arsenic in subarctic lakes influenced by gold mine effluent: the

  • ccurrence of organo-arsenicals and 'hidden' arsenic. The Scient of the Total Environment. Vol 180, pp

165-182.

  • Golder. 2010. Dispersion of Effluent from Con Mine, Northwest Territories. Technical Memorandum.

Project 09-1328-0022/3000. May 2010. Moore, JW, Sutherland, DJ, and VA Beaubien. 1979. Algal and invertebrate communities in three subarctic lakes receiving mine wastes. Water Research. Vol 13, Issue 12, pp 1193-1202.

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Month YEAR Newmont Goldcorp – Confidential I Presentation Name 17

Goals and Objectives of MKP Study

Peg and Keg lakes looking towards Yellowknife, 2019

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Goals and Draft Objectives of MKP Study

Overall study goals

  • Increase our understanding of the MKP lakes system and how it has been

influenced in the past to aid in the predictions of the future state under continued use

  • Make recommendations for future monitoring of conditions in the MKP

Draft objectives for discussion

  • Assess how conditions in the MKP lakes system are influenced by past and
  • ngoing discharges from Con Mine
  • Assess how conditions in the MKP lakes system will be influenced by future

discharges from Con Mine

  • Recommend on-going post-closure monitoring of the MKP lakes system beyond

study period

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Information Needs for Discussion

Objective Information Available Information Gaps for Discussion

Assess how conditions in the MKP lakes system are influenced by past and ongoing discharges from Con Mine

  • Historical toxicity, water quality

and sediment quality but not for all years, locations or parameters

  • limited biological data
  • surveys demonstrated no over-

wintering habitat for fish

  • bathymetry, flow, limnological, water quality

[surface, porewater], sediment characteristics and quality data

  • understanding of temporal/spatial patterns

in water quality, sediment quality, and benthic invertebrate data

  • identification of parameters of potential

concern Assess how conditions in MKP lakes system will be influenced by future discharges from Con Mine

  • GoldSim model built with

estimates of loadings from WTP, runoff, seepage/sediment

  • GoldSim model calibrated at

Peg Lake outflow

  • more accurate and updated loadings

estimates for WTP, runoff, seepage, and sediment in GoldSim model

  • what changes in MNML’s water

management strategy have the potential to change MKP conditions either positively and negatively? Recommend on- going post-closure monitoring of MKP beyond study period

  • Existing environmental data set
  • Is it appropriate to develop closure “targets”

for the MKP lakes system

  • Is there a suitable analog to monitor as an

indicator of overall system condition?

  • What long-term monitoring should continue

in the MKP lakes system?

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Outline of MKP Study with AEMP/MDMER/EEM for Con Mine

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Next Steps for 2020

Q1 Q2 Q3 Q4

Supplementary monitoring in MKP Prepare draft outline of study design Present draft outline at Workshop #2 Discussions/planning for collaborative components of study Submit MKP Study Design to MVLWB - Dec 1 Update study design

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Month YEAR Newmont Goldcorp – Confidential I Presentation Name 22

Peg Lake Inlet, 2019

Thank you for attending!

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MKP Study Design Workshop #1 - Summary Notes

Page 1 of 3 10-December-2019

MKP Study Design Workshop #1 - Summary Notes

Date: Tuesday, December 10th, 2019 (8:30am to 4pm) Location: Chateau Nova, Yellowknife, NT Attendees: Dwight Grabke and Scott Stringer (Miramar Northern Mining Ltd.); Hilary Machtans and Alison Humphries (Golder Associates Ltd.); Tyree Mullaney, Heather Scott, and Katherine Harris (Mackenzie Land and Water Board); Rick Walbourne and Bryana Matthews (Government of Northwest Territories); Anne Wilson and Gabriel Bernard-Lacaille (Environment and Climate Change Canada); Adelaide Mufandaedza (North Slave Métis Alliance); and Sara Gillis (Yellowknives Dene First Nation). 1. Purpose of Workshops, Mandate of Working Group, Topics and Format of Workshop #1

Series of workshops schedule throughout the term of the licence to discuss and gather input on upcoming licence, monitoring, reporting requirements, or site remediation activities.

Current schedule is included in our Engagement Plan V2.0

Workshop #1 will be a combination of group discussion and smaller group work to engage parties and utilize our time effectively to aid in the development the MKP study objectives and a prioritized list of information needs. If there are opportunities for collaborative work on the study with other interested parties, MNML will be open to discussing those at the workshop as well.

Gather interested stakeholders for 1-2 workshops/year to discuss a variety of topics relative to the closure and post closure of the site.

MNML will chair workshops and document the discussions for consideration in the various

  • utputs from the relative topics.

2. Discussion of Goals and Objectives of MKP Study (objectives updated based on discussion during December 10th Workshop) MKP Study Goals Goals through this workshop is to utilize proponent and stakeholder collaboration:

to establish a list of prioritized and sequenced objectives to be monitored over the 5 year MKP study period

to identify suitable monitoring analog as an indicator of system condition during continued monitoring beyond the study period into post closure MKP Study Objectives Objective 1: Assess conditions in MKP lakes system (better understand the ‘black box’)  compile and review existing dataset and previous studies to evaluate the peak impacted baseline as a basis to measure improvement along the trend line into the future.

identify spatial variability in water and sediment quality (e.g., is there a lake, or on a coarse scale part of a lake, or a channel between lakes that is contributing more loading of a certain parameter)

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MKP Study Design Workshop #1 - Summary Notes

Page 2 of 3 10-December-2019

provide baseline sediment quality and benthic invertebrate data to compare over time to help answer the question how conditions in the MKP lakes system are changing over time

identify the types, quantity and quality for loadings to the MKP system, including WTP, runoff, seepage, sediment

consider impacts of seasonal ice cover on seasonal water quality, contaminate cycling, exclusion, stratification, mixing, and flushing

build a conceptual model for the ‘black box’ of the MKP lakes system that includes individual lakes and different potential sources of loads (e.g., current treated effluent, sediment flux, seepage, runoff, snowmelt, upstream lake, etc.), for which quantification or assumptions of the loading rates will be required Objective 2: Assess how conditions in MKP lakes system are, or will be, influenced by future discharges from Con Mine  assess how discharges of treated effluent impact water quality in the MKP lakes system in the short and long-term given the other current loadings to the system  identify parameters of potential concern parameters of potential concern for water and sediment quality, identify temporal trends in water quality  refine current model with consideration of more accurate watershed characteristics, precipitation, depths/surface areas/volumes of lakes, flows and loadings from the channels between and drainage areas of lakes

identify areas where there may be opportunities for changes in water management strategy (timing of discharge, frequency of discharge, etc.) to benefit the conditions within MKP Objective 3: Identify on-going post-closure monitoring of M-K-P beyond study period  identify if closure objectives and/or criteria are appropriate for this system and the timing of their development, where does the underlying liability reside  identify suitable analog as an indicator of system condition during continued monitoring beyond the study period into post closure 3. Identify and Prioritize Information Needs for Each Study Objective  Group broke into smaller groups to identify information needs/gaps for

  • ne study objective, rank information needs from highest to lowest priority and map

information need to a study outline (Figure 1). Figure 1 reflects the outcomes of the discussion

  • f the group during the workshop; MNML will consider this feedback when designing the study
  • utline.

 MNML is open to other interested parties gathering information collaboratively or in parallel during the study period to help inform the study but the Study Design requirements should be limited to those components that MNML is completing. 4. Next Steps Plan for 2020

develop study outline based on based on the information gathered today and further consultation as needed through Q1-Q2 2020

present proposed study outline to Working Group in advance of the Q2/Q3 in Workshop #2,

prepare study design for submission to the MVLWB based on feedback from Workshop #2

continue discussions in 2020 of study areas that could be done in collaboration with interested parties

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MKP Study Design Workshop #1 - Summary Notes

Page 3 of 3 10-December-2019

Figure 1 : Overview of Meg, Keg, Peg Study Deliverables, Information Needs and Activities, 2019-2026

Notes: The figures reflects the outcomes of the discussion of the group during the workshop; MNML will consider this feedback when designing the study outline. On-going activities (e.g., monitoring and reporting) outside of the MKP Study are shown in blue boxes and activities related to the MKP Study are shown in red boxes. a) Annual summaries will be limited to a description of work completed on the study design, If MNML identifies the need for a significant change to the study design, MNML will submit a revised study design to the MVLWB. b) The MKP Study Report will include a plain language summary of study findings. AEMP = Aquatic Effects Monitoring Program; EEM = Environmental Effects Monitoring; JFB MZB = Jackfish Bay mixing zone boundary; MVLWB = Mackenzie Valley Land and Water Board; MDMER = Metal and Diamond Mining Effluent Regulations; MKP = Meg, Keg, Peg lakes; MNML = Miramar Northern Mining Ltd.