WATER TER QUALIT ALITY Y MODELLING ODELLING AND D EFFL FLUEN UENT T QUALIT ALITY Y CRI RITERI TERIA MVLWB Technical Session Snap Lake Mine Final Closure, and Water Licence and Land Permit Renewal July 16 to 18, 2019 PUBLIC LIC PRESEN ENTATION ION
OUTL TLINE • Water Quality Models - Site, Snap Lake, and Downstream • Effluent Quality Criteria • Model Sensitivities and Near-field Modelling 1
WATER TER QU QUAL ALIT ITY Y MO MODELS ELS
INTR TRODU ODUCTION CTION 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 , '" I .-----------· Effluent Constructed Quality Wetland Criteria Design 3
INTR TRODU ODUCTION CTION CONTINUED TINUED M O D E L A S S U M P T I O N S • Extended Care and Maintenance - Modular water treatment plant (WTP)/reverse osmosis (RO) unit operational • Closure - Buildings decommissioned, North Pile covered, modular WTP/RO unit operational, passive treatment systems constructed and functioning • Post-closure - The modular WTP/RO unit decommissioned, effluent from passive treatment systems meets effluent quality criteria (EQC) - Passive treatment systems were not included in the Site model 4
SITE E MODEL DEL 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 5
➔ ~ ~ -■-■ ~ SITE E MODEL DEL CONCEPTU CEPTUAL DIAGR GRAMS AMS E X T E N D E D C A R E & M A I N T E N A N C E A N D P O S T - C L O S U R E C L O S U R E .----~ ------. Sump 1 Sump 1 Sewage I 7L__J ___ \ Treatment I I Plant I ... !- --- ~:=:::::::::::::::: r <: ,, '' I_ - - - Sump 2 Sump 2 I I Qtb :::········ O I Qi ,i,,,~ Sump 3 Sump 3 ... Snap Lake Water ... , Modular WTP ,, North Pile , Snap Lake Management North Pile + RO Unit ~ Lr ' Pond T~ L) i---- ~== ~ :::; .............. Sump 4 '" I Sump 4 I . I . I I .. . ... ,, Underground Sump 5 I. , Sump 5 J Mine I 0 1 . I I .. . I. Western Western ---- .. I- - - - ➔ L.---··-··-··-··-··-· I .... ... Embankment Embankment Catchment Catchment L.-·-··-··-··-··-··-··-··-··-··-··-··-··-··.J L.-·-··-··-··-··-··-··.J -----> -··-·> Pumping ing Runoff off + Seepage Seepage Outflo low (gravit ity) ) ················> 6
SITE E MODEL DEL INFL FLOWS & OUTFL TFLOWS The North Pile sumps included inflows and outflows from: 1. Direct precipitation 1 5 2. Inflows/concentrations from the North Pile 3. Inflows/concentrations from sump catchment area 2 6 4. Inflows/concentrations from other sumps North th Pile e 5. Evaporation 3 Sump mp 6. Pumping to the water management pond/outflow Volum lume/ e/ 4 Conc 7
SITE E MODEL DEL WATER ER QUALI ALITY SOURCE CE TERMS Source Water er Quality lity Monit itor orin ing Station tion Rib berm seepage SNP 02-02 Fine processed kimberlite runoff (before cover) SNP 02-02 Fine processed kimberlite runoff (after cover; May and June) SNP 02-05 Fine processed kimberlite runoff (after cover; July to April) SNP 02-02 Fine processed kimberlite draindown SNP 02-02 North Pile embankment seepage SNP 02-02 and SNP 02-05 Western embankment catchment area SNP 02-02 Natural catchment area Stream 1 Developed catchment area SNP 02-05 Sewage treatment plant SNP 02-16i Underground water quality SNP 02-01 8
■ ■ ■ ■ ■ ■ ■ ■ SITE E MODEL DEL PREDICTED DICTED WATER ER MANAGEME GEMENT T POND D INFL FLOWS S AND OUTFL FLOWS A N N U A L O U T F L O W S ( m 3 ) A N N U A L I N F L O W S ( m 3 ) Catchment Runoff Precipitation Underground Evaporation Sewage Treatment Plant North Pile Modular WTP + RO Unit Seepage to Snap Lake 5,000 35,000 13,000 4,000 150,000 154,000 270,000 5,000 9
□ ■ ■ ■ □ SITE E MODEL DEL PREDICTED DICTED DISCHAR SCHARGES S TO SNAP LAKE Annual al Dischar scharge e to Snap Lake e (m 3 ) Operations ECM and Closure Post-closure >18,000,000 300,000 270,000 22 22 Annual Volume Discharged to Snap Lake (m 3 ) Millions Annual Volume Discahrged to Snap Lake (m 3 ) 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 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 Year Year Water Treatment Plant Modular Water Treatment Plant + Reverse Osmosis Unit Underground Mine Sump 3 Sump 5 10 10
~ ~j SITE E MODEL DEL PREDICTED DICTED NITRA TRATE TE CONCENT CENTRA RATION TIONS • In Closure, concentrations in Sump 3 are predicted to increase because Sump 3 receives a greater proportion of North Pile runoff • In Post-closure, concentrations in the sumps are predicted to decrease because of the assumption that the sumps fill to their maximum volume before overflowing Sump 3 250 ECM Closure Post-closure Sump Volu olumes (m 3 ) Nitrate, as N (mg/L) 200 Sump Closu osure Post-closu losure 150 3 8,300 61,000 100 5 11,700 68,000 111111111111111111111111 50 0 ' ' ' ' ' I O ' I , , I , I 2018 2020 2022 2024 2026 2028 2030 2032 2034 2036 2038 2040 2042 2044 2046 2048 Year Reviewe wer comment nts: 11 11 • ECCC-08, MVLWB-55: discuss decreases in predicted sump concentrations
□ □ ■ □ ■ SITE E MODEL DEL ANNUAL AL NITRA TRATE TE LOAD D TO SNAP LAKE Annual al Nitrate e Load ad to Snap ap Lake e (kg N/yr) Operations ECM and Closure Post-closure 90,000 5,000 <7,000 100,000 100,000 Post-closure Operations ECM Closure 90,000 90,000 Nitrate Load to Snap Lake (kg N/yr) Nitrate Load to Snap Lake (kg N/yr) 80,000 80,000 70,000 70,000 60,000 60,000 50,000 50,000 40,000 40,000 30,000 30,000 20,000 20,000 10,000 10,000 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 Modular Water Treatment Plant + Reverse Osmosis Unit Underground Mine Sump 3 Sump 5 ECM - Extended Care and Maintenance 12 12
SNAP LAKE MODEL EL 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 13 13
-■-■ □ ,-■- ■-■-■-■ ~ ■ ■ ;-·-·- SNAP LAKE MODEL EL CONCEP EPTU TUAL AL DIAGRAMS GRAMS E X T E N D E D C A R E & M A I N T E N A N C E P O S T - C L O S U R E A N D C L O S U R E I J, D ··········· D Sump 3 Natural Water . Natural North Pile , Outflow Runoff Management Runoff Pond I I I !i I I ..., I 1 I Modular WTP , L Camp Use + RO Unit D- ··-· ··············· CJ I . - .. - .. - .. - .. - .. _, I L , North Pile Snap Lake Downstream . Snap Lake .-··-··) Sewage Treatment I A Plant I ____ D I D ·········...: D Sump 5 ■ CJ i Site Runoff Underground , L Site Runoff Outflow Downstream Mine - ·> -··-·> Seepage Pumping ing Runoff off Outflo low ) ················> - - 14 14
SNAP LAKE MODEL EL INPUT PUTS S FOR R EXTENDED ENDED CARE RE & MAINTEN TENANCE ANCE AND CLOSU SURE RE North Pile Seepage Camp Use Outflow Site Runoff ) Modular WTP + RO Unit Discharge Water Management Pond Seepage Stream 1 Other Inflows/Outflows • Precipitation Other Stream Inflows • • Evaporation • Seepage from Underground Mine to Snap Lake Reviewe wer comment nts: 15 15 • GNWT-89: Snap Lake volume, inflows and loading
SNAP LAKE MODEL EL INPUT PUTS S FOR R POST-CLOSURE OSURE North Pile Seepage Outflow Site Runoff ) Sump 5 Outflow Sump 3 Outflow Stream 1 Other Inflows/Outflows • Precipitation • Other Stream Inflows • Evaporation 16 16
SNAP LAKE MODEL EL WATER TER QUAL ALITY SOURCE E TERMS Input Water er Qualit lity Sour urce ce Ter erm Treated effluent discharge from the water Monitoring data from SNP 02-17 and SNP 02-17b treatment plant Treated effluent discharge from the modular water ECM and Closure: Median from the Site model treatment plant + reverse osmosis unit Water management pond pumping to Snap Lake Monitoring data from SNP 02-14 (2003-2004) Water management pond pumping to the ECM and Closure: Median in the water management underground mine pond from the Site model Calibration period: Monitoring data from SNP 02-14 Water management pond seepage ECM and Closure: Median in the water management pond from the Site model 17 17
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