Feasibility Study and Technical Report - Pretivm

pumped from the underground and used in process. In response, the baseflowinputs to Brucejack Lake will also be altered during this period. The undisturbedrunoff value in the flow schematic accounts for these reduced baseflows.• With a settled dry density of 1.46 t/m 3 and a slurry consisting of 65% solids byweight, the paste backfill will exude some water during the curing phase. It isassumed that this additional water will be pumped out with the seepage waterand sent to treatment.Figure 20.1Brucejack Lake Water Balance Model Schematic – Operations (AverageConditions)water displaced bytailings & waste rockdisposalvoidlosses802299BrucejackCreekBrucejack52,908 50,219Lakeundisturbedrunofftailings slurry3,4663,447fluidizingwatervoidlosses2,2043634372,380WTP2,816336oremoisture68ProcessPlant573paste backfillUndergroundMinemilllosses725concentrate2,580groundwaterOff-SiteNote:Units are m 3 /d. Red arrows indicate pumping routes.An average annual outflow of 2,205 m 3 /h from Brucejack Lake has been estimated forthe LOM, an average increase of approximately 5% above existing conditions(2,103 m 3 /h). The increase in flow results from the introduction of tailings slurry waterand the displacement of water by the deposition of tailings and waste rock.Pretium Resources Inc. 20-19 1291990200-REP-R0012-02Feasibility Study and Technical Report on the BrucejackProject, Stewart, BC