WATER LICENCE AMENDMENT TECHNICAL SESSIONS 22.Jan.2015 The De - - PowerPoint PPT Presentation

The De Beers Group of Companies

22.Jan.2015

MV2011L2-0004 SNAP LAKE WATER LICENCE AMENDMENT TECHNICAL SESSIONS

The De Beers Group of Companies 1

Section Title

Overview of Water Licence Amendment Applications - TDS

• De Beers is applying to change the quality of water allowed to be

discharged to Snap Lake

• Necessary for De Beers to continue sustainable operations at

Snap Lake Mine that provide ongoing benefits to local communities and the economy of the Northwest Territories

• De Beers has, for several years, presented water models have

shown that TDS loading to Snap Lake is increasing due to mining, and that current water licence limits for whole-lake TDS and chloride in effluent will be exceeded without mitigation

• Water licence renewed in 2012 required De Beers to propose new

water quality objectives and effluent limits for TDS and other parameters for Snap Lake Mine based on aquatic toxicity studies

The De Beers Group of Companies 2

Overview of Water Licence Amendment Applications - TDS

• Studies of the aquatic organisms of Snap Lake show that previous

licence limit for TDS was overly protective

• Studies of mitigation technologies to reduce TDS loadings show

that existing limits cannot be met using available technologies

• Application also proposes minor regulatory and administrative

changes

• Proposed increases to TDS limits meet the requirements of the

Mackenzie Valley Environmental Impact Review Board to prevent significant adverse impacts to fish, the aquatic environment, human health and traditional land use

The De Beers Group of Companies 3

Overview of Water Licence Amendment Applications - TDS

Effluent Quality Criteria (EQC)

• A concentration of a substance

in water above which effects to aquatic health may occur

• Protective of aquatic life in

Snap Lake Water Quality Objective (WQO)

• Concentration of a substance in

effluent that can be discharged without exceeding the WQO Effluent Mixing Zone Outfall

The De Beers Group of Companies 4

Overview of Water Licence Amendment Applications - TDS

Interim TDS Limits Life-of-Mine TDS Limits Proposed changes

• Rescind whole-lake average 350 mg/L
• SSWQO of 684 mg/L
• EQC of 850 mg/L (average monthly)
• Chloride regulated as part of TDS
• Rescind whole-lake average 350 mg/L
• SSWQO of 1,000 mg/L
• EQC of 960 mg/L (average monthly)
• Chloride, sulphate regulated as part of

TDS Mitigation to Meet Limits

• “unmitigated” plus current practice

(storage, dilution, targeted grouting)

• RO-based water treatment, plus dilution,

targeted grouting Effective Period

• As soon as possible (Q2) until LOM limit

is determined (assume Q3 2015)

• Q3 2015 to end of licence term

Purpose

• Allows mine to operate in compliance in

short term while mitigation is tested and LOM limit is set

• Long-term sustainable operation of Snap

Lake Mine Meets Measures of EA1314-02

• Yes
• Yes

The De Beers Group of Companies 5

Overview of Water Licence Amendment Applications - TDS

TDS near diffuser SNP02-20e under Upper Bound and Lower Bound unmitigated scenarios

Effective period of proposed interim SSWQO Proposed interim SSWQO 684 mg/L Proposed Life-of-mine SSWQO of 1,000 mg/L Current licence limit 350 mg/L

Near Diffusers

The De Beers Group of Companies 6

200 400 600 800 1,000 1,200 1,400 1,600 1,800 2004 2006 2008 2010 2012 2014 2016 2018 2020 2022 2024 2026 2028 Total Dissolved Solids (mg/L) Year Upper Bound Lower Bound

Overview of Water Licence Amendment Applications - TDS

TDS in effluent (SNP02-17B) under Upper Bound and Lower Bound unmitigated scenarios

Effective period of proposed interim EQC Proposed interim EQC 850 mg/L Proposed Life-of-mine EQC of 960 mg/L

Effluent

The De Beers Group of Companies 7

Overview of Water Licence Amendment Applications - TDS

• Decision on EA1314-02 to replace requirement to maintain TDS <350 mg/L in Snap Lake
• Measures 1a-d require that SSWQO for TDS and constituent ions meet the following
• bjectives:

EA Measure How Met by Proposed Amendments 1a Aquatic system is protected SSWQO has been proposed based on technically defensible aquatic toxicity testing focused on resident species 1b Water in Snap Lake is safe to drink (Health Canada) Nitrate, nitrite and fluoride in Snap Lake will not exceed Health Canada’s Drinking Water Guidelines 1c Fish are safe to eat in Snap Lake and downstream TDS does not affect safety of fish consumption; AEMP monitoring will continue 1d TDS not detectable in Mackay Lake (44 km) Snap Lake TDS will not be detectable in Mackay Lake (will not cause changes outside of range of natural variability)

The De Beers Group of Companies 8

Overview of Water Licence Amendment Applications - TDS

• EA Measure 2 requires De Beers to implement water treatment or other

mitigations to achieve the numerical SSWQO and associated EQC set by the MVLWB, which meet the objectives of Measure 1.

EA Measure How Met by Proposed Amendment 2 Mitigation to be implemented to achieve SSWQO and EQC (interim) Treatment of effluent will not be required to meet the proposed interim SSWQO of 684 mg/L and EQC of 850 mg/L in the short term (2015); testing of mitigation will be completed Mitigation to be implemented to achieve SSWQO and EQC (LOM) Proposed SSWQO of 1,000 mg/L and EQC of 960 mg/L can be met by treating a portion of effluent using RO- based water treatment technology

• De Beers’ proposal for TDS amendments is consistent with commitments made

during EA1314-02 as listed in Appendix B of the report of EA.

The De Beers Group of Companies 9

Overview of Water Licence Amendment Applications - TDS

• De Beers has given due consideration to the MVEIRB’s Suggestions

EA Suggestion How Taken into Consideration in Proposed Amendment 1 Update AEMP Response Framework

• De Beers proposes to submit an update to the AEMP

Design Plan within 1 year of amendment

• De Beers proposes a Special Study to address data gaps

and improve model certainty 2 Water quality in Snap Lake to achieve aesthetic objective 5 years post-mine operations

• TDS in Snap Lake will return below aesthetic objective

within 7 years 3 Evaluate technologies using BATEA approach

• BATEA for Snap Lake Mine concludes that RO-based

treatment is technologically, environmentally and economically viable to achieve proposed SSWQO

The De Beers Group of Companies 10

Overview of Water Licence Amendment Applications - TDS The proposed TDS SSWQO of 1,000 mg/L is: 1. PROTECTIVE (not over-protective) 2. APPROPRIATE (based on site-specific studies) 3. ACHIEVABLE (can be met through mitigation) The proposed interim SSWQO of 684 mg/L allows the mine to

• perate in compliance in the short term while mitigation is

tested and LOM limit is set by the MVLWB

The De Beers Group of Companies 11

Supporting Documents – TDS Amendments

• Model Reports: (Groundwater Flow Model; Snap Lake Site Water Balance

Model; Site Water Quality Model; Snap Lake Hydrodynamic and Water Quality Model)

• All reports of toxicity studies to establish Chronic Effects Benchmarks in

support of SSWQOs

• TDS Response Plan
• Development of Effluent Quality Criteria (EQC) Report
• Report on preliminary evaluation of BATEA for Snap Lake Mine
• Responses to Information Requests: April 2014; May 2014; January 2015
• Engagement records filed December 2013, June 2014, November 2014,

January 2015 (in-camera)

• All other materials filed as part of EA1314-02 during the joint MVLWB-

MVEIRB proceedings and MVEIRB proceedings

The De Beers Group of Companies 12

Summary of Findings BATEA Study

• Treatment of mine effluent for removal of chloride is uneconomic

(HATCH 2014)

• The BATEA study concludes that the protective TDS EQC for Snap Lake
• f 960 mg/L can be achieved using available technologies
• Combined environmental and technical evaluation rates RO-based

treatment as best available for Snap Lake Mine

• Economic viability of RO technology at Snap Lake Mine depends on:

1. The TDS limits set by the Land and Water Board (how much treatment is required) 2. Future mine outflows (how much effluent needs to be treated) 3. The efficiency of the treatment (how much TDS can be removed)

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Mitigation to Meet Proposed EQC Un Under r Interi rim m EQC of 850 mg/L during ng 2015: 5:

• Allows mine to operate in compliance in short term while mitigation is tested

and life-of-mine limit is set

• Continue with existing methods for managing TDS: storage; controlled

dilution; targeted grouting

• Implementation and testing of proof-of-concept Reverse-osmosis (RO)

treatment unit arriving on winter road Un Under r Life-of

• f-Min

Mine EQC of 960 mg/L (2015-2028) 028)

• RO-based treatment of a portion of the effluent using a phased approach

(progressive addition of treatment capacity and brine reduction)

• Net reduction in TDS loading to Snap Lake by offsite disposal of solid waste

brine

• Complemented by controlled dilution and targeted grouting

The De Beers Group of Companies 14

Next Steps - Implementation of RO Proof-of-Concept Phase

• RO module to arrive by winter road 2015
• Installation and commissioning in Q3 2015
• Life-of-mine EQC set in water licence
• Operation of the proof-of-concept RO system to gather important

information about:

• Recovery efficiency
• Optimized configuration
• Design of brine minimization
• Decisions on design of subsequent phase(s) must be made Q3

2015 to complete designs by Q4 2015

The De Beers Group of Companies 15

Modular RO Treatment Single modular treatment plant Multiple modular treatment plant

Spiral-Wound RO Module

PermNte C

• ncentrate-
• '

...

The De Beers Group of Companies 16

Complementary Mitigation Progress of targeted grouting:

• Multiple campaigns since 2011 to improve understanding

and applicability

• Significant effort and investment in targeted grouting since

2014

• Ongoing monitoring and evaluation of one grouted heading
• Currently optimizing materials and techniques based on
• ngoing data evaluation

The De Beers Group of Companies 17

Summary of Water Licence Amendment - TDS 1. The protective TDS EQC for Snap Lake of 960 mg/L can be achieved using RO technology 2. The viability of RO technology at Snap Lake Mine depends on:

• Appropriate site-specific TDS limits set by the Land and

Water Board

• Future mine outflows (how much water needs to be

treated)

• The efficiency of the treatment (how much TDS can be

removed)

• 3. Protective, appropriate and achievable TDS limits will support

continued sustainable operations at Snap Lake Mine that provide ongoing benefits to local communities and the economy of the Northwest Territories

The De Beers Group of Companies 18

TDS TOXICITY Y TESTING NG

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Conceptual Site Model – Schematic Food-Web for Snap Lake

The De Beers Group of Companies 20

Conceptual Site Model – Relevant Exposure Pathways

Contaminant Sources Mine Water Exposure Media Water Column Receptors of Concern Benthic Invertebrate Community Demersal Fish Pelagic Fish Lake Productivity

(phytoplankton and zooplankton)

1 2 2 2 3 3

Notes:

• 1. TDS loading from treated mine effluent discharged through permanent diffuser
• 2. Potential direct toxicity
• 3. Potential indirect effects due to degradation of food supply

Schematic of Pathways and Receptors of Concern

The De Beers Group of Companies 21

TDS Toxicity Test Data Used for SSWQO

Test est Sp Species ecies End ndpoint

• ints

[TDS] mg mg/L /L Pseudokirchneriella subcapitata (green alga) Growth: IC10 >1,474 Navicula pelliculosa (diatom) Growth: IC10 >1,487 Brachionus calyciflorus (rotifer) Rate of population increase: IC10/IC20 (geomean, n=3) >1,330 Cyclops vernalis (copepod) Growth: IC20 (n=2) >1,508 Daphnia magna (water flea) Reproduction: IC20 (geomean, n=5) >1,099 Chironomus dilutus (chironomid) Growth: IC10 >1,379 Salvelinus namaycush (Lake Trout) Dry fertilization LC20 fry survival 991 Dry fertilization IC20 fry weight and length (growth) >1,490 Wet fertilization LC20 fry survival >1,484 Wet fertilization IC20 fry weight and length (growth) >1,484 Thymallus arcticus (Arctic Grayling) Dry fertilization LC20 fry survival >1,419 Dry fertilization IC20 fry weight and length (growth) >1,419 Wet fertilization LC20 fry survival >1,414 Wet fertilization IC20 fry weight and length (growth) >1,414 Pimephales promelas (Fathead Minnow) Hatching of fertilized eggs, survival, growth: IC20 >2,202

The De Beers Group of Companies 22

Ceriodaphnia dubia Data Excluded from SSWQO

• Not a resident genus; waterfleas found in Snap Lake but better

represented by genus Daphnia, found in Snap Lake

• Very high variability in C. dubia results

– IC20s: <274 to >1,497 mg/L – IC10s: 218 to 1,074 mg/L

• Possibility of laboratory artefacts (20% Perrier water for culturing

and for control)

• In 2013 waterfleas increased in abundance in Snap Lake despite

whole-lake TDS concentrations 228 to 284 mg/L, maximum TDS 301 mg/L

• Not possible to choose technically defensible IC10 or IC20 for C.

dubia

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Proposed TDS SSWQOa of 1,000 mg/L (= 1 ppt) Protective

• Primary reliance on CCME (2003; Resident Species Approach and

Recalculation Approach), considering more recent science

• Based on all components of the Snap Lake aquatic ecosystem (benthos,

plankton, fish – per Conceptual Site Model)

• Species tested determined in consultation with regulators and communities

(began consultation in early 2011 [e.g., April 20, 2011 Technical Workshop]); all requests for additional testing and/or changes to test procedures met

• Below the lowest negligible effects concentration for the most sensitive

resident taxon, Daphnia (1,000 mg/L vs >1,099 mg/L)

• Daphnia make up 1 to 7% of the zooplankton in Snap Lake; other

zooplankton less sensitive to TDS (>1,330 to >1,508 mg/L)

• Acute toxicity to Daphnia not seen at effluent TDS concentrations to 2,660

mg/L

aIncludes chloride and sulphate

The De Beers Group of Companies 24

Information Sources

• Golder Associates Ltd. 2013. Development of Total Dissolved

Solids (TDS) Benchmark for Aquatic Life for Snap Lake. Submitted to De Beers Canada Inc and Mackenzie Valley Environmental Review Board, Yellowknife, NWT, Canada.

• Chapman PM. 2014a. Additional Daphnia magna 21-day TDS

toxicity test results. Technical Memorandum. Submitted to De Beers Canada Inc. and Mackenzie Valley Land and Water Board. Yellowknife, NWT, Canada. June 10, 2014.

• Chapman PM. 2014b. Copepod TDS toxicity tests results.

Technical Memorandum. Submitted to De Beers Canada Inc. and Mackenzie Valley Land and Water Board. Yellowknife, NWT,

• Canada. June 10, 2014.

The De Beers Group of Companies 25

Information Sources (cont’d)

• Chapman PM. 2014c. Snap Lake Mine: additional toxicity testing

to determine a site-specific water quality objective for total dissolved solids in Snap Lake. Technical Memorandum. Submitted to De Beers Canada Inc. and Mackenzie Valley Land and Water

• Board. Yellowknife, NWT, Canada. November 23, 2014.
• De Beers Canada Inc. 2014. MV2011L2-0004 Water Licence

Amendment Post-EA Information Package. Yellowknife, NWT,

• Canada. November 28, 2014.
• De Beers Canada Inc. 2015. Response to MV2011L2-0004 Water

Licence Amendment Information Requests. Yellowknife, NWT,

• Canada. January 8, 2015.

The De Beers Group of Companies 26

Conceptual Site Model – Schematic Food-Web for Snap Lake

The De Beers Group of Companies 27

Water Quality Objectives Summary

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Terminology Review

1. WQO – water quality objective

• Concentration of a substance in

Snap Lake that is protective of aquatic life

2. DWG – Drinking water guideline

• Concentration of a substance in

Snap Lake that is protective of drinking water (health-based, not aesthetic)

3. EQC – Effluent Quality Criteria

• Concentration of a substance

that can be discharged without exceeding an in-lake water quality objective (WQO)

Outfall EQC – Effluent Quality Criteria (end-of-pipe) Mixing Zone WQO - Water Quality Objective (in-lake) DWG – Drinking Water Guideline (in-lake)

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Water Quality Objectives – Apply in Snap Lake for Life of Mine 1. Process for Selecting WQOs:

• Select protective and appropriate WQO specifically for Snap

Lake from the scientific information available

• Consider modifying factors such as hardness and chloride
• Calculate based on conditions in Snap Lake (e.g., pH and

temperature)

• Determine whether a health-based drinking water guideline

(DWG) exists (Measure 1b)

• Choose the more restrictive: aquatic life vs drinking water
• Meet Measures in Report of Environmental Assessment and

Reasons for Decision

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Water Quality Objectives – Toxicity Modifying Factors

• Hardness reduces potential toxicity of TDS, chloride, fluoride, nitrate,

and metals

• Chloride reduces potential toxicity of nitrite
• Literature base to support ameliorating effects (referenced in AEMP

reports, Post-EA package, IR responses, Nitrite Report)

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Water Quality Objectives – Apply in Snap Lake for Life of Mine TDS = 1,000 mg/L (Golder 2014)

• Protective of aquatic life
• Based on site-specific testwork
• No national health-based drinking water guidelines (DWG)

Fluoride = 1.5 mg/L (Health Canada 2012)

• DWG
• Protective of aquatic life (lower than SSWQO = 1.94 mg/L)

Nitrate = 10 mg-N/L (Health Canada 2012)

• DWG
• Protective of aquatic life (lower than SSWQO = 16.4 mg-N/L)

Ammonia = 3.9 mg-N/L (CCME 1999 with updates to 2014)

• Aquatic life guideline (chronic)
• Variable, based on pH and temperature in Snap Lake

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Water Quality Objectives – Apply in Snap Lake for Life of Mine Nitrite = 0.2 mg-N/L (BCMOE 1986, 2009)

• Aquatic life guideline
• Lower than health-based DWG of 1.0 mg-N/L
• Incorporates chloride as a toxicity modifying factor

Chloride and Sulphate (Golder 2014)

• Included in TDS
• No national health-based DWGs for chloride or sulphate
• Testwork included chloride and sulphate

Phosphorus = 0.011 mg/L (Wetzel 2001)

• Maintain oligotrophic status in Snap Lake
• Approved benchmark under the Response Framework (De Beers 2014)

Metals = Variable (CCME 1999 with updates to 2014; De Beers 2002)

• Hardness-dependent, aquatic life (lower than DWGs)

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In-lake Water Quality Objectives

Param ameter Water r Qualit lity Objective (mg/L) Source TDS 1,000 Golder (2014) Fluoride 1.5 Health Canada (2012) Ammonia, as N 3.9 (chronic) CCME (1999 with updates to 2014) 20 (acute) USEPA (2013) Nitrate, as N 10 Health Canada (2012) Nitrite, as N 0.2 BCMOE (1986, 2009) Aluminum 0.1 CCME (1999 with updates to 2014) Arsenic 0.005 CCME (1999 with updates to 2014) Chromium 0.0089 CCME (1999 with updates to 2014) Copper 0.0079 De Beers (2002) Lead 0.007 CCME (1999 with updates to 2014) Nickel 0.15 CCME (1999 with updates to 2014) Zinc 0.03 CCME (1999 with updates to 2014) Total phosphorus 0.011 Wetzel (2001)

• WQOs used to derive EQC are appropriate, protective and meet the REA Measures
• The water in Snap Lake is safe to drink, aquatic ecosystem and fish populations are protected, and

fish are safe to eat