OUTS TSTANDING ANDING INFORM ORMATI TION N EFFL FLUEN UENT T QUALIT ALITY Y CRI RITERI TERIA Technical Workshop Snap Lake Mine Final Closure, Water Licence and Land Permit Renewal September 19, 2019 PUBLIC LIC PRESEN ENTATION ION
OUTL TLINE • Summary of Updates - Changes between Version 1 and Version 2 of the linked water quality models (Site, Snap Lake, Downstream) and effluent quality criteria • Board IR 1 – Screening Approach • Board IR 2 – Development of Effluent Quality Criteria and Supporting Evidence • Board IR 3 – Mixing Zones • Board IR 4 – Environmental Assessment Measures 1(a) and 1(d) 1
SUMM MMAR ARY Y OF OF UPD PDATE TES
SUMMAR MARY Y OF DIFFE FERENC RENCES BETWE WEEN EN V.1 AND V.2 OF Change ges s Since nce v1 (in n red) THE EFFLUE UENT QUALI ALITY CRITERIA TERIA REPOR ORT Time e Pe Period iod Version ion 1 Technic nical al Session on Version ion 2 1. Screening process was not 1. Screening process was 1. Screening process was completed to identify completed to identify POPC updated and completed to parameters of potential identify POPC concern (POPC) 2. Mixing zone (1) boundary is 2. Mixing zone (1) boundary is 2. Mixing zone (1 to 3) 200 m from outfall 200 m from outfall boundaries are 200 m from Before outfall gravity fed 3. Proposed to maintain 3. Proposed EQC: 3. Proposed EQC: collection effluent quality criteria (EQC) • Nitrate • Nitrate system from Operations • TSS Same EQC: • 18 parameters • Faecal coliforms • TSS pH Faecal coliforms • • • pH 4. Assume modular WTP/RO 4. Assume modular WTP/RO 4. Assume modular WTP/RO will be required will be required will not be required 3
SUMMAR MARY Y OF DIFFE FERENC RENCES BETWE WEEN EN V.1 AND V.2 OF Change ges s Since nce v1 (in n red) THE EFFLUE UENT QUALI ALITY CRITERIA TERIA REPOR ORT Time e Pe Period iod Version ion 1 Technic nical al Session on Version ion 2 1. Screening process was 1. Screening process was 1. Screening process was completed to identify POPC completed to identify POPC updated and completed to identify POPC 2. Mixing zone boundaries are 2. Mixing zone boundaries 2. Mixing zone boundaries are 200 m from outfalls could be as little as 100 m 200 m from outfalls After gravity from outfalls fed 3. Proposed EQC: 3. Proposed EQC: 3. Proposed EQC: collection • Nitrate • Nitrate • Nitrate system is • TSS • TSS Same EQC: established • pH • pH • TSS • pH 4. Assume passive treatment 4. Assume passive treatment 4. Assume passive treatment systems will be required systems will be required systems will not be required 4
WATER ER QUALI ALITY MODELS ELS No C Chang nges es Since ce v1 L I N K E D M O D E L S Water Quantity Model Downstream Lakes Water Quality Site Water Quality Model Model Snap Lake Water Quality Model Effluent Constructed Quality Wetland Criteria Design 5
SITE E MODEL DEL No C Chang nges es Since ce v1 L I N K E D M O D E L S Water Quantity Model el Downstream Lakes Water Quality Site Water Quality Model Model Snap Lake Water Quality Model Effluent Constructed Quality Wetland Criteria Design 6
SITE E MODEL DEL - BEFORE ORE GRAVITY FED COLLECTION ECTION SYSTEM EM Change ges s Since nce v1 (in n red) Ver ersio ion 1 and Tech echnic ical al Session ion Ver ersio ion 2 Sump 1 Sump 1 Sewage Sewage Treatment Treatment Plant Plant Sump 2 Sump 2 Sump 3 Sump 3 Water Water Modular WTP North Pile North Pile Snap Lake Management Snap Lake Management + RO Unit Pond Pond Sump 4 Sump 4 Underground Underground Sump 5 Sump 5 Mine Mine Western Western Embankment Embankment Catchment Catchment Pumping ing Runoff off + Seepage Seepage 7
SITE E MODEL DEL - AFTER ER GRAVITY FED COLLECT ECTION ON SYSTEM No C Chang nges es Since ce v1 Ver ersio ion 1, 1, Technica hnical l Session ion and Ver ersio ion 2 Sump 1 Sump 2 Runoff f + Seepage age Seepage age Sump 3 Snap Lake North Pile Outflo low (gravi vity ty) Sump 4 Sump 5 Western Embankment Catchment 8
SITE E MODEL DEL PREDICTED DICTED DISCHAR SCHARGES S TO SNAP LAKE No C Chang nges es Since ce v1 Annual al Disc schar harge ge to Snap p Lake e (m 3 ) Before Gravity Fed Collection After Gravity Fed Collection Operations (Approved) System System >18,000,000 300,000 270,000 22 22 Annual Volume Discharged to Snap Lake (m 3 ) Annual Volume Discahrged to Snap Lake (m 3 ) Millions Millions Operations ECM Closure Post-closure 20 20 18 18 16 16 14 14 12 12 10 10 8 8 6 6 4 4 2 2 0 0 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 Year Year Water Treatment Plant Water Management Pond Underground Mine Sump 3 Sump 5 9
SITE E MODEL DEL ANNUAL AL NITRA TRATE TE LOAD D TO SNAP LAKE Change ges s Since nce v1 (in n red) Ver ersio sion 1 and Tec echnical ical Sess ssio ion Annual al Nitrate e Load ad to Snap ap Lake e (kg N/yr) Before Gravity Fed Collection After Gravity Fed Collection Operations System System 90,000 (actual) 5,000 7,000 250,000 (approved) Ver ersio sion 2 Annual al Nitrate e Load ad to Snap ap Lake e (kg N/yr) Before Gravity Fed Collection After Gravity Fed Collection Operations System System 90,000 (actual) 14,000 16,000 250,000 (approved) 10 10
SNAP LAKE MODEL EL No C Chang nges es Since ce v1 L I N K E D M O D E L S Water Quantity Model el Downstream Lakes Water Quality Site Water Quality Model Model Snap Lake Water r Quality Model Effluent Constructed Quality Wetland Criteria Design 11 11
SNAP LA LAKE MODEL EL - BEFORE ORE GRAVIT ITY Y FED Change ges s Since nce v1 (in n red) COLLECTION ECTION SYSTEM EM Ver ersio ion 1 and Tech echnic ical al Session ion Ver ersio ion 2 Water Water Natural Natural North Pile Management North Pile Management Runoff Runoff Pond Pond Modular WTP + RO Camp Use Camp Use Unit Snap Lake Snap Lake Sewage Sewage Treatment Treatment Plant Plant Underground Underground Site Runoff Downstream Site Runoff Downstream Mine Mine Seepage Pumping ing Runoff off Outflo low 12 12
SNAP LAKE MODEL EL - AFTER ER GRAVITY FED COLLECTI ECTION SYSTEM EM No C Chang nges es Since ce v1 Sump 3 Natural Outflow Runoff Runoff Seepage age North Pile Snap Lake Downstream Outflo low Sump 5 Site Runoff Outflow 13 13
DOWNSTREAM TREAM LAKES MODEL EL No C Chang nges es Since ce v1 L I N K E D M O D E L S Water Quantity Model el Downstre ream Lakes es Water er Quality Site Water Quality Model Model Snap Lake Water Quality Model Effluent Constructed Quality Wetland Criteria Design 14 14
DOWNSTREAM TREAM LAKES MODEL EL CONCEP CEPTU TUAL AL DIAGRAM GRAM No C Chang nges es Since ce v1 EXTEN ENDED DED CARE & MAINTENA ENANCE, CE, CLOSURE E MacKay Node 22 AND POST-CL CLOS OSURE Lake West MacKay Lake Embayment King River Camsell King Lake Lake DSL10 Northeast DSL9/ North Lake Lake KING01 DSL8 Snap Lake Lac Capot DSL1 DSL2 DSL4 & 5 DSL6 DSL7 Blanc 15 15 DSL - Downstream lake
SCREE REENIN NING G AP APPR PROACH CH Board IR 1
SCREENI EENING PROC OCESS SS TO IDENT ENTIFY FY PARAMETERS ETERS OF POTENT ENTIAL CONCERN CERN “Clarification and further evidence are required from De Beers on how a single approach to parameter screening is appropriate as well as why these two reasons are no longer applicable to account for uncertainty.” • In both Version 1 and Version 2 of the EQC Reports, one screening approach was used to identify parameters of potential concern regardless of the specific discharge source water and discharge locations • In Version 2 of the EQC Report, the screening process does not use predictions from the modular water treatment plant /reverse osmosis unit to identify POPC • Short-term variabilities in water quality concentrations that may occur as a result of construction and demolition activities have not been accounted for in the site model in Version 1 or Version 2 of the EQC Report 17 17
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