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 11 th and 12 th , 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 2
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 operations 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 original 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). 5
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. 6
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. 7
Measure 1(c) (continued): 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 of 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. 8
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 ( HC 5 ). • This level of protection (95% of species) has been chosen among many jurisdictions as it is thought that an effect on only 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. 11
SSWQOs for Snap Lake - TDS • HC 5 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 HC 5 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). 14
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 of 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
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