The Government of the Northwest Territories Public Hearing - - PowerPoint PPT Presentation

The Government of the Northwest Territories

Public Hearing Presentation De Beers Canada Mining Inc. Snap Lake Project Water Licence Amendments

MV2011L2-0004

Dettah, NT March 11th and 12th, 2014

Presentation Overview

• Introduction
• Background – Proposed WL amendments
• Environmental Assessment
• SSWQOs for Snap Lake
• SSWQOs for Mackay Lake
• EQC for TDS
• Monitoring and Adaptive Management
• Other Amendments
• Closing

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Introduction

• The GNWT seeks a resolution that ensures the Snap Lake

Mine operations have safeguards in place to protect the biophysical environment, and also encourage the ongoing

• perations of Snap Lake Mine to support the development of

a thriving socio-economic environment in the Northwest Territories.

• ENR is presenting water-related evidence and

recommendations on behalf of the Government of the Northwest Territories.

3

Background – Proposed WL Amendments

• Connate groundwater infiltrating into the underground

workings from footwall contains elevated TDS.

• TDS levels have trended upward in Snap Lake over past

several years.

• Higher than expected inflows and concentrations of TDS have

necessitated the need to evaluate mitigation options, including the re-visiting of current EQC.

4

Background – Proposed WL Amendments

• Original application in December 2013 requesting removal of

350 mg/L TDS whole-lake average.

• Referred to EA as this condition was linked to measures of the
• riginal EA (EA 01-004).
• EA concluded in October 2014.
• Interim application submitted in November 2014.
• Post-EA submission related to original application submitted

with revised SSWQO and EQC (November 2014).

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Environmental Assessment

• In September 2014, the Review Board issued its Report of

Environmental Assessment which included two measures.

• Measure 1 requires the MVLWB to set SSWQOs and lists

various objectives that must be met related to human and aquatic health.

• Measure 2 requires that mitigation will be implemented, as

required, to meet the objectives of Measure 1.

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Environmental Assessment

• Measure 1(a) relates to the protection of the aquatic

environment.

– The GNWT will provide recommendations related to this measure later in the presentation.

• Measure 1(b) relates to the protection of human-health.

– SSWQOs proposed by De Beers are reflective of Health Canada guidance and will ensure compliance with this measure.

• Measure 1(c) requires that fish are safe to eat in Snap Lake.

– ENR is unaware of any direct linkage between TDS and the edibility of

• fish. Regardless, the AEMP will continue to monitor fish tissue and

ensure that fish are safe to eat.

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The GNWT recommends that any amendment to Water Licence MV2011L2-0004 or subsequent licence continue to include the requirement that the AEMP shall include monitoring for the purpose

• f measuring Project-related effects on the following components of

the Receiving Environment:

• i. Fish health;
• ii. contaminant levels in fish flesh due to changes in water

quality in Snap Lake and/or the NE Lake; and

• iii. the taste of fish, to be completed with the communities,

due to changes in water quality in Snap Lake.

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Measure 1(c) (continued):

Environmental Assessment

• Measure 1(d) states that the SSWQO must ensure that “no

Total Dissolved Solids or its constituent ions from the Snap Lake Mine effluent will be detectable, relative to the range of natural variability, at the inlet to Mackay Lake, 44 km downstream of Snap Lake.”

– The GNWT will provide recommendations related to this measure later in the presentation.

9

SSWQOs for Snap Lake - TDS

• The GNWT undertook a review of toxicity work and SSWQO

derivation completed by De Beers related to TDS. Several deviations from the CCME guidance were identified:

– Exclusion of data – Procedures and methods used to interpret the data

• As a result of these concerns, ENR requested their consultant,

MESL, establish an SSD curve using the toxicity data from De Beers, to derive an SSWQO for Snap Lake.

10

SSWQOs for Snap Lake - TDS

• An SSD curve is used to determine the concentration at which

5% of the species in a receiving body would experience an effect (HC5).

• This level of protection (95% of species) has been chosen

among many jurisdictions as it is thought that an effect on

• nly 5% of species still preserves ecosystem functionality.
• MESL initially established a curve based on 10% effect level to

5% of the species, as this is the preferred effects level recommended by CCME.

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SSWQOs for Snap Lake - TDS

• HC5 of 399 mg/L TDS was calculated at a 10% effects level. At

this level a 10% effect to 5% of the species within Snap Lake would be anticipated.

• The presence of unbounded values resulted in higher

uncertainty and may over-estimate the toxicity of TDS at this level.

• As a result, the GNWT requested that MESL run a second SSD

curve, based on a 20% effects level.

12

SSWQOs for Snap Lake - TDS

• The second curve completed by MESL was based on a 20%

effects level and resulted in an HC5 of 690 mg/L. This is the level at which ENR would anticipate a 20% effect to 5% of the species within Snap Lake.

– ENR is confident this value meets Measure 1(a) of the Report of EA

• This information suggests that above 690 mg/L, greater than

20% effects levels in the most sensitive species in Snap Lake would occur.

– Unclear whether or not Measure 1(a) will be achieved.

13

SSWQOs for Snap Lake - TDS

• De Beers has requested an “interim” value of 684 mg/L TDS

– Supported by ENR

• De Beers has also requested a “long-term” value of 1000 mg/L

TDS.

– Additional information and clarity is required to ensure that the proposed long-term SSWQO would be protective of the aquatic ecosystem of Snap Lake, as required by Measure 1(a) of the REA. – Further study and assessment is needed to ensure these levels do not cause harm to food web dynamics (short term) and fish (long term).

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SSWQOs for Snap Lake - TDS

• SSWQO of 690 mg/L TDS would be adequately protective of

the aquatic ecosystem of Snap Lake and be in compliance with Measure 1(a).

• The proposed EQC within De Beers interim Water Licence

application could be implemented in the short-term, assuming that a SSWQO of 690 mg/L would still be met in Snap Lake. GNWT recommends that the SSWQO for TDS within Snap Lake be set at 690 mg/L

15

SSWQOs for Snap Lake - Nitrate

• The CEQG for nitrate is 3.0 mg-N/L for the protection of aquatic life.
• Based on recent sampling results it appears that an SSWQO of 3.0

mg-N/L is achievable.

• Values proposed by De Beers are based on the protection of human

health, not aquatic health. Additional evidence is needed to demonstrate that the proposed SSWQO of 10 mg-N/L would be protective of aquatic life in Snap Lake.

GNWT recommends a SSWQO of 3 mg-N/L for nitrate in Snap Lake.

16

SSWQOs for Snap Lake - Nitrite

• The CEQG for nitrite is 0.06 mg-N/L for the protection of aquatic

life.

• Based on recent sampling results it appears that an SSWQO of 3.0

mg-N/L is achievable.

• Values proposed by De Beers are based on the protection of human

health, not aquatic health. Additional evidence is needed to demonstrate that the proposed SSWQO of 0.20 mg-N/L would be protective of aquatic life in Snap Lake.

GNWT recommends an SSWQO of 0.06 mg-N/L for nitrite in Snap Lake.

17

SSWQOs for Snap Lake - Fluoride

• The CEQG for fluoride is 0.12 mg-N/L for the protection of

aquatic life.

• Values proposed by De Beers are based on the protection of

human health. Additional evidence is needed to demonstrate that the proposed long-term SSWQO of 1.5 mg-N/L is protective of aquatic life in Snap Lake.

• Current data indicates that levels of Fluoride in Snap Lake are

above the CEQG.

18

SSWQOs for Snap Lake - Fluoride

• The 2013 AEMP Annual Report notes that increasing levels of hardness

can reduce the potential for toxicity effects associated with fluoride.

• The BCMOE has proposed a hardness dependent guideline for fluoride,

but considers it to be an interim guideline due to the confounding effects

• f temperature and hardness on fluoride toxicity. Until the effects of

hardness on fluoride toxicity are better understood, the CEQG for fluoride should continue to be applied as an SSWQO for Snap Lake.

Considering current levels are above the CEQG, GNWT recommends additional investigation into potential mitigation for the reduction of fluoride in Snap Lake be conducted, with a goal of reducing levels below the CEQG.

19

SSWQOs for Mackay Lake

• Measure 1(d) states “No Total Dissolved Solids or its

constituent ions from the Snap Lake mine effluent will be detectable, relative to the range of natural variability, at the inlet to Mackay Lake, 44 km downstream of Snap Lake.”

• There are several components of this measure which must be

interpreted to ensure the Measure is met: – What is the precise location of discussion? – What is the range of natural variability at Mackay Lake?

20

SSWQOs for Mackay Lake

• In De Beers’ opinion, the intent of Measure 1(d) is that TDS

not be detectable outside of the range of natural variability within Mackay Lake.

• ENR concurs with De Beers that the intent of Measure 1(d) is

to ensure that TDS and its constituents from Snap Lake is not detectable within Mackay Lake.

• Appropriate monitoring and trend analysis will have to be

implemented upstream of Mackay Lake to ensure this does not occur, and Measure 1(d) is met.

21

SSWQOs for Mackay Lake

• De Beers has proposed a special 2 year study to

characterize natural conditions in Mackay Lake.

• ENR utilized all information currently available to

determine the natural variability in Mackay Lake.

– Both measured and calculated TDS are reported in the existing water quality data sets. – Calculated concentrations of TDS provide a more accurate and consistent basis for evaluating the range of natural variability of TDS levels in surface water.

22

23

SSWQOs for Mackay Lake

GNWT recommends that concentrations of TDS and its constituent ions within Mackay Lake be maintained within the range of natural variability as outlined within Table 1 and 2, until additional evidence is provided to the MVLWB that better defines this range.

24

SSWQOs for Mackay Lake

• A review of the Downstream Lakes Model (DLM) used by De

Beers identified that several model nodes were excluded and that no modeled predictions for constituent ions of concern have been developed and documented for the DLM.

• Additional modeling is needed to confirm that proposed Snap

Lake EQC will not result in the detection of effluent at Mackay Lake outside of the range of natural variability.

25

SSWQOs for Mackay Lake

• The Downstream Lakes Model (DLM) should be revised to

include model nodes for King Lake (upstream and downstream stations), and the inlet to Mackay Lake (i.e. located in the embayment at the mouth of the Lockhart River, within 100 m of the mouth of the river);

• The DLM should be revised to include predictions of TDS and

constituent ions of concern (including, but not limited to chloride, fluoride, and nitrate), at each of the existing and recommended model nodes;

• The DLM should be revised to include lower and upper bounds

for the water quality predictions by incorporating additional flow estimates (e.g., 10th and 90th percentile outflows) during baseline and operations.

26

Effluent Quality Criteria - TDS

• There are various relevant factors to note when deriving

SSWQOs for both Snap Lake and Mackay Lake.

• While an SSWQO of 690 mg/L has been recommended to

ensure the aquatic environment of Snap Lake is protected (Measure 1(a)), it is not clear at this point that this value will also prevent the detection of effluent at Mackay Lake (Measure 1(d)).

• Therefore, conditions in both Snap Lake and Mackay Lake

must be considered when determining the EQC for Snap Lake effluent.

27

Effluent Quality Criteria - TDS

• An EQC of 850 mg/L AML/1003 mg/L MDL may be permissible

in the interim provided that

– an SSWQO of 690 mg/L is not exceeded within Snap Lake, and – this level of discharge, over the period proposed, will not result in a detectable change of TDS and its constituent ions in Mackay Lake.

The GNWT recommends that for the protection of the aquatic ecosystem within Snap Lake an EQC for TDS within Snap Lake be calculated based on a SSWQO of 690 mg/L.

28

Monitoring and Adaptive Management

• The existing Water Licence includes a requirement for an

Aquatic Effects Monitoring Program.

• The current AEMP will require updating to reflect new EA

measures.

The GNWT recommends the existing AEMP be reviewed and updated as necessary in order to implement measures recommended in EA 1314-02 and approved by the Responsible Ministers.

29

Monitoring and Adaptive Management

• Additional stations will be required in the AEMP to confirm

that effluent from Snap Lake is not detectable in Mackay Lake beyond the range of natural variability.

The GNWT recommends including AEMP monitoring locations within Mackay Lake that will be used to ensure that Measure 1(d) is being

• implemented. The precise locations should be determined in

consultation with Aboriginal groups and other interested parties to ensure that the monitoring results will provide a satisfactory confirmation that the intent of Measure 1(d) is met.

30

Monitoring and Adaptive Management

• Additional modeling points are required to confirm that Snap

Lake EQC will not result in the detection of effluent at Mackay Lake outside of the range of natural variability. These modeling stations should be included as part of an updated AEMP.

The AEMP should be updated to include the modeling nodes for King Lake (upstream and downstream stations), and the inlet to Mackay Lake (i.e., located in the embayment at the mouth of the Lockhart River, within 100 m of the mouth of the river).

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Monitoring and Adaptive Management

• While the current 6-day rolling average EQC for chloride is

being met, higher concentrations can occur between sampling resulting in 31-day averages that are above EQC.

• Enforcement of a 31-day EQC would be logistically challenging

as it requires duplicate samples for 31 consecutive days.

The GNWT recommends that the whole lake average sampling program continue to be carried out in Snap Lake.

32

Monitoring and Adaptive Management

• The AEMP Framework will need to be updated to include

conditions related to meeting the EA measures in Snap Lake and Mackay Lake.

The GNWT recommends that the AEMP Response Framework include appropriate action levels and triggers to ensure that the EA Measures will be met in Snap Lake and downstream into Mackay Lake.

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Monitoring and Adaptive Management

The following recommendations are offered to ensure that the Adaptive Management Plan (AMP) that is ultimately established for the Snap Lake Diamond Mine site provides a basis for identifying and implementing mitigation measures:

Responses necessary to ensure that the effluent discharge limits are met, effluent is not acutely toxic, water quality objectives are met, surface water is not chronically toxic, sediments are not toxic, and biological integrity is maintained must be identified in the AMP and implemented in a timely manner. The metrics utilized for determining if adaptive management actions are needed to address site-related issues should include effluent chemistry, effluent toxicity, surface- water chemistry, surface-water toxicity, sediment chemistry, sediment toxicity, fish-tissue chemistry, invertebrate-tissue chemistry, phytoplankton community structure, zooplankton community structure, benthic invertebrate community structure, and fish health.

34

Monitoring and Adaptive Management

The following steps should be identified in the terms and conditions

• f the amended water licence, to ensure that the AMP is developed

in a timely manner and meets the expectations of reviewers:

• The permittee shall develop a Terms of Reference (TOR) for the

updated response framework. The TOR shall be submitted to the MVLWB within 30 days of licence issuance.

• The permittee shall submit a draft of the updated response

framework to the MVLWB for review within 90 days of Licence issuance;

• The permittee shall submit the final version of the updated

response framework to the MVLWB within 150 days of Licence issuance.

35

Other Amendments

• Section 6 of the GNWT’s Intervention outlines

recommendations on the other administrative and operational amendments requested by De Beers, in addition to the SSWQO and EQC amendments outlined previously.

• De Beers responded in Section 4.1 of their

Response to Interventions and agreed with the GNWT on six proposed amendments (Part A, E(3), F(8), SNP 02-02, 02-03, SNP 02-17B).

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Questions?

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