Feasibility Study and Technical Report - Pretivm

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weight, the paste backfill will exude some water during the curing phase. This additionalwater is assumed to be pumped out with the seepage water and sent to treatment.Excess treated groundwater will be used as fluidizing water and discharged to BrucejackLake at depth. Fluidizing water is required at an average rate of 3,447 m 3 /d in order tomaintain flow in the discharge line to Brucejack Lake during periods when thickenedtailings are used for backfill paste. Reclaim from the lake is also required, as there areperiods when the groundwater inflows are predicted to be less than the processrequirement.An average annual outflow of 2,215 m 3 /h from Brucejack Lake has been estimated forthe life of mine, an average increase of about 5% above existing conditions (2,103 m 3 /h).The increase in flow results from the introduction of tailings slurry water and thedisplacement of water by the deposition of tailings and waste rock. Outflows fromBrucejack Lake are assumed to be of suitable water quality for discharge to BrucejackCreek.25.4.7 HYDROGEOLOGICAL ASSESSMENTA calibrated 3D numerical hydrogeologic model was used to estimate the inflow ofgroundwater to the proposed underground mine workings at the Project. The rate ofgroundwater inflow to the underground workings is predicted to remain relatively stablethroughout the development of the VOK Zone resource during the first 14 years of minelife, ranging between 2,250 m 3 /d and 2,650 m 3 /d. The rate of inflow to the undergroundworkings is predicted to increase to a peak of approximately 3,750 m 3 /d in Year 15, withthe development of the West Zone resource. During Years 16 to 21 of mine life,predicted inflows range between 2,700 m 3 /d and 3,000 m 3 /d, before decreasing toapproximately 2,400 m 3 /d in the final two years of mine life.The inflow estimates are most sensitive to the hydraulic properties of the bedrockrepresented in the model. Increasing the hydraulic conductivity by a factor of fiveresulted in the highest inflow estimates, with predicted inflows increasing by a factor ofapproximately two and average annual inflows of approximately 5,900 m 3 /d. The peakinflow associated with the increased hydraulic conductivity scenario is predicted to beapproximately 8,900 m 3 /d in Year 15 of operations. Decreasing the hydraulicconductivity by a factor of five resulted in a commensurate decrease in inflow (factor of0.5), with average annual inflows of approximately 1,394 m 3 /d. The peak inflowassociated with the decreased hydraulic conductivity scenario is predicted to beapproximately 2,017 m 3 /d.Using the base case, or best estimate simulation, the water table elevation in theimmediate vicinity of the underground workings is drawn down significantly during minedewatering operations, by up to 120 m in the mine footprint at the end of mine life. Thecone of depression associated with this dewatering drawn down has an areal extent ofapproximately 1.5 km by 2.5 km.Pretium Resources Inc. 25-5 1291990200-REP-R0012-02.1Feasibility Study and Technical Report on the BrucejackProject, Stewart, BC
25.4.8 TAILINGS DELIVERY SYSTEMThe tailings placement system for Brucejack Lake has been designed utilizing the bestavailable technology for the confinement of fine particulates to the bottom layer of animpoundment.25.5 ENVIRONMENTALPretivm is committed to operating the mine in a sustainable manner and according totheir guiding principles. To this end, Pretivm has been carrying out baseline studies andaboriginal engagement and consultation for several years. Pretivm has good and ongoingworking relationships with the Skii km Lax Ha, Nisga’a Nation, the Tahltan Nation,as well as other First Nations in the region. Environmental baseline studies have beenunderway since 2009. Information from the baseline studies have provided a robustunderstanding of biophysical, social-economic and current land use conditions in thearea. Fish do not occur within any immediate receiving environments and the occurrenceand distribution of wildlife species of potential concern is well understood.The goal is to develop the Project such that long-term environmental impacts areminimized. Waste rock and tailings management are being planned to minimizepotential for water quality issues in Brucejack Lake and downstream receivingenvironments with predictive studies on-going. The closure and reclamation plan willfocus on closing the adits, removing all site infrastructure, removing the transmissionline, and closing the access road including removing the bridges and culverts andrevegetation.Pretivm has formally entered provincial and federal EA processes and are workingtowards submission of Application for the EAC under the BCEAA and the EnvironmentalImpact Statement under the CEAA in Q4 2013.25.5.1 GEOCHEMISTRYThe development of proper waste management strategies requires an assessment of theARD/ML characteristics of the mine waste. In addition, potential adverse effects on thedownstream receiving environment from mine waste need to be assessed by waterquality prediction. The two strategies selected for the long-term management of minewaste at the Project are disposal in the underground mine and subaqueous disposal inBrucejack Lake.Underground disposal involves the storage of waste rock in the underground mineworkings. Waste rock and flotation tailings will also be stored in Brucejack Lake. Theunderwater storage in the (flooded) underground mine and in the lake will preventoxidation of pyrite and other metal sulphides that may cause ARD.Considering the ARD/ML characteristics of the mine waste and its potential adverseeffect on the downstream receiving environment, the following conclusions can be drawnregarding the selected strategies for mine waste disposal:Pretium Resources Inc. 25-6 1291990200-REP-R0012-02Feasibility Study and Technical Report on the BrucejackProject, Stewart, BC
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Report to:Pretium Resources Inc.Fea
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TABLE OF CONTENTS1.0 SUMMARY ......
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12.2 DATA VERIFICATION BY SNOWDEN .
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16.7 MOBILE EQUIPMENT REQUIREMENTS
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20.1 SUSTAINABILITY AND ENVIRONMENT
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26.4.2 HYDROGEOLOGICAL RECOMMENDATI
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Table 13.23 Occurrences of Gold in
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LIST OF FIGURESFigure 1.1 Simplifie
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Figure 16.11 Extent of Mine Develop
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hertz .............................
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atomic emission spectroscopy ......
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Mineable Shape Optimizer ..........
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VOK Domain 2 ......................
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1.2 PROPERTY DESCRIPTION AND LOCATI
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1.4 MINERAL RESOURCE ESTIMATESSnowd
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Table 1.2West Zone Mineral Resource
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Figure 1.1Simplified Process Flowsh
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1.7 MINING METHODSThe underground m
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Figure 1.2Overall Site LayoutE 4300
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Figure 1.4Knipple Transfer Station
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outflow. This approachdischarge thr
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summary of the overall operating co
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The Project schedule identifies the
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2.1 QUALIFIED PERSONSThe qualified
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Report Section Company QP23.0 Adjac
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4.0 PROPERTY DESCRIPTION AND LOCATI
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4.3 STATUS OF MINING TITLESThe Prop
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Figure 4.3Pretivm Mineral ClaimsSou
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5.0 ACCESSIBILITY, CLIMATE, LOCALRE
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5.2 CLIMATE AND PHYSIOGRAPHYThe cli
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6.0 HISTORYInformation in this sect
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Figure 6.1West Zone Underground Vei
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6.1 WORK COMPLETED BY SILVER STANDA
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7.0 GEOLOGICAL SETTING ANDMINERALIZ
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Figure 7.1Tectonic Setting of the B
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7.2 LOCAL GEOLOGY - SULPHURETS MINI
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Altered Stuhini Group rocks and Mit
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Figure 7.4Sulphurets Mining Camp Ge
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y the Brucejack Fault as well as by
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Previously, some of the rocks strad
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Figure 7.6Brucejack Property Geolog
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Figure 7.6 (con’t)Brucejack Prope
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more distal (i.e. down temperature)
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more heavily altered than those abo
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Figure 7.8Brucejack Property Minera
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Figure 7.10South-north Cross-sectio
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WEST ZONEThe West Zone gold-silver
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Figure 7.12VOK to West Zone Geologi
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Figure 7.14West Zone Drillholes and
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steep, is generally associated with
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Figure 7.15Trace Element Analysis b
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for which an age of c.110 Ma has be
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Figure 8.1Brucejack Deposit Mineral
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Figure 9.13D Geophysical Model Sche
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10.0 DRILLINGInformation in this se
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Figure 10.1Core in Wooden Core Boxe
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Figure 10.3Brucejack Property Diamo
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The cut PQ samples weighed approxim
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submitted to ALS. In addition, a re
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Primary sample gold concentrations
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12.0 DATA VERIFICATIONIndependent s
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12.2 DATA VERIFICATION BY SNOWDENSn
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Figure 12.4Sample Verification Resu
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Year Program ID Laboratory ** Gravi
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13.3.2 2012 TO 2013 TEST SAMPLESIns
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Table 13.7 Conceptual Master Compos
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ALSInspectorateFire Assay (g/t) Met
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13.3.6 ORE HARDNESS TEST WORKTable
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Table 13.14 Sample Specific Gravity
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In general, there was a reduction i
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Figure 13.5 Effect of Primary Grind
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In 2012 and 2013, most of the flota
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Further cleaner tests were conducte
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Figure 13.14 Effect of Cleaner Flot
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SampleIDWZ-2CompositeCompositeBJ-AC
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The 2012 and 2013 tests routinely i
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Figure 13.17Cumulative Stage GRG ve
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Figure 13.21 Silver Cyanide Extract
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Table 13.24 Head Sample Cyanidation
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Based on the findings of the prelim
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Primary Grind/Regrind SizesConcentr
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Further cyanide leach tests were ca
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including samples with low head gra
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Grade (g/t) Recovery/Extraction (%)
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Figure 13.28 Variability Test Resul
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Table 13.31Locked Cycle Tests Resul
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Table 13.33Conventional Thickening
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13.3.11 CONCLUSIONSA review of prel
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Table 13.37Head Grade(g/t)Metallurg
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• geological interpretation and m
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to form a series of seemingly strat
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14.6 COMPOSITING OF ASSAY INTERVALS
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In the high-grade domains (includin
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Table 14.3Parameters to Describe Go
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14.8.3 HIGH-GRADE DOMAINS - PROBABI
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analysis. Any target blocks that re
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For VOK and West Zone the interpola
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Table 14.9Comparison of the Mean Co
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the economic viability of the depos
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14.15 RESOURCE REPORTINGThe mineral
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15.0 MINERAL RESERVE ESTIMATES15.1
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Table 15.1Net Smelter Return Parame
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15.4 MINING SHAPESAMC used the Mine
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Strike length varies considerably w
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15.7 MINERAL RESERVESMineral reserv
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Figure 15.4Reserve Shapes and Minin
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16.2 MINE DESIGN16.2.1 ACCESS AND R
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Figure 16.2Brucejack Twin Declines
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Figure 16.4Typical Level Plan - 1,2
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Table 16.1Development Design Parame
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Figure 16.7Mineable Stope Shapes -
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Once the stope footprint is slashed
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16.3.3 STOPE SEQUENCEThe mining seq
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Stopes that will not be re-exposed
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Table 16.5LOM Backfilling - Waste R
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Figure 16.11Extent of Mine Developm
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• development of the 1,210 and 1,
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Figure 16.13Life of Mine Production
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Table 16.7LOM Tonnes and GradesYear
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Table 16.8Rock Mass PropertiesUnitU
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AMC estimated ore recovery in the w
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FULL-WIDTH UNDERCUTSThe Project min
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Table 16.10Mine Infrastructure Exca
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with lesser components supplied by
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un was completed representing glaci
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Table 16.12Underground Development
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TRANSMIXERSShotcrete will be delive
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The VOK Zone and West Zone mining a
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Figure 16.17 shows a ventilation co
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• regular inspection of the conve
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On low-head applications, a submers
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Figure 16.18Dewatering PlanPretium
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Figure 16.20CrusherThe 42 in wide b
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16.9.3 POWER REQUIREMENTS AND ELECT
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Electrical power will be supplied t
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To supply service water to the high
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16.9.7 WORKSHOP AND STORESThe maint
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Radio communications will be establ
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16.9.11 PORTAL STRUCTUREA portal st
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propane consumption. Table 16.18 sh
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16.10 PASTE FILL DISTRIBUTIONP&C co
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Figure 16.33Paste Fill Distribution
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Figure 16.35Pre-production Paste Fi
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RoleHeadCountMaintenance (72)Mainte
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17.0 RECOVERY METHODS17.1 MINERAL P
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The process plant will consist of t
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17.1.4 PLANT DESIGNMAJOR DESIGN CRI
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• a belt conveyor, 914 mm wide by
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CONCENTRATE REGRINDINGThe flotation
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The dried tabling concentrate will
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solution strength. The solution wil
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PROCESS CONTROL AND INSTRUMENTATION
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• vendors’ instrumentation pack
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18.0 PROJECT INFRASTRUCTURE18.1 OVE
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Figure 18.1Brucejack Overall Site L
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18.2 GEOTECHNICAL18.2.1 OVERVIEWThe
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18.3 ACCESS18.3.1 ACCESS ROADSThe B
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Figure 18.3Knipple Glacier Access R
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available in the winter and also pr
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18.5 GRADING AND DRAINAGEThe site w
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AVALANCHE FREQUENCYAvalanche freque
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• portal fuel storage• conveyor
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Operations CampSize 2 avalanches fr
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Figure 18.5Access Road Avalanche Ha
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and dated June 2013. As requested b
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Figure 18.7Photo of Typical Slopes
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• the design of special towers to
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modular construction where possible
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collect waste water during maintena
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water treatment plant to increase t
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Air/vacuum valves will be installed
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Figure 18.10Foot Print of 3% Deposi
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A pre-manufactured trailer will be
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• fuel storage• vendors’ inst
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18.17 OFF-SITE INFRASTRUCTURE18.17.
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18.17.3 BOWSER AIRSTRIPRegular char
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INSTRUMENT APPROACH PROCEDURESAn IA
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AERODROME PERSONNEL AND MAINTENANCE
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TRANSPORT MODE OPTIONSTruckThere ar
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SBT has the ability to mobilize cra
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Pretivm is committed to a process t
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engage with the Nisga’a Lisims Go
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Average monthly temperature data us
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The fisheries resources and fish ha
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was conducted on the NPR values of
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all modelling exercises, the accura
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16 corridor is recovering from the
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• reporting and feedback mechanis
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Approximately 47% of the tailings w
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20.1.8 WASTE MANAGEMENTMine WastesP
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from the site. Fixed equipment, suc
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• Forest Act (BC)• Forest and R
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Table 20.5List of Federal Approvals
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21.1.2 ESTIMATE BASE DATE AND VALID
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…costs not directly attributable
Page 395 and 396: • small tools• consumables• c
Page 397 and 398: The total cost for Major Area 33 -
Page 399 and 400: The unit cost estimates are based o
Page 401 and 402: MINE OPERATING COSTSThe total under
Page 403 and 404: Table 21.7Summary of Process Operat
Page 405 and 406: Table 21.8Summary of Backfilling Op
Page 407 and 408: DescriptionLabourForceTotal Cost($/
Page 409 and 410: 22.0 ECONOMIC ANALYSIS22.1 INTRODUC
Page 411 and 412: Figure 22.1Pre-tax Cash FlowCumulat
Page 413 and 414: transport the concentrate to a buil
Page 415 and 416: Figure 22.4Pre-tax Payback Period S
Page 417 and 418: Canadian development expense and 60
Page 419 and 420: 23.0 ADJACENT PROPERTIESSnowden not
Page 421 and 422: 23.2 HIGH PROPERTYThe Teuton Resour
Page 423 and 424: managers, and the mining manager, a
Page 425 and 426: MANAGEMENT PROCEDURESThe EPCM contr
Page 427 and 428: Figure 24.2Level 1 Execution Schedu
Page 429 and 430: Capital equipment purchases will be
Page 431 and 432: Construction work will be split int
Page 433 and 434: provided with dedicated emergency p
Page 435 and 436: econciliation to the freight consol
Page 437 and 438: PROJECT TEAM RESPONSIBILITIESIt is
Page 439 and 440: WBS Area PretivmEPCMTeamUnderground
Page 441 and 442: 24.1.15 RISK MANAGEMENTA Risk Asses
Page 443 and 444: There may be opportunities to optim
Page 445: The conceptual layout is preliminar
Page 449 and 450: 26.0 RECOMENDATIONS26.1 GEOLOGYThe
Page 451 and 452: • Further test work to identify t
Page 453 and 454: The estimated cost for the above-me
Page 455 and 456: • Careful planning as well as det
Page 457 and 458: 26.5.6 BRUCEJACK OUTLET CONTROL STR
Page 459 and 460: • Further groundwater quality and
Page 461 and 462: 27.0 REFERENCES27.1 AVALANCHE HAZAR
Page 463 and 464: Price, W. (2005). Mend Report 9.1c:
Page 465 and 466: Britton, J. M. and Alldrick, D. J.,
Page 467 and 468: Olssen. L., Jones, I.. 2012b. Preti
Page 469 and 470: 28.0 CERTIFICATES OF QUALIFIED PERS
Page 471 and 472: 28.2 IVOR W.O. JONES, M.SC., CP, FA
Page 473 and 474: 28.3 JOHN HUANG, PH.D., P.ENG.I, Ji
Page 475 and 476: 28.5 HAMISH WEATHERLY, M.SC., P.GEO
Page 477 and 478: 28.7 SABRY ABDEL HAFEZ, PH.D., P.EN
Page 479 and 480: 28.9 CATHERINE SCHMID, M.SC., P.ENG
Page 481 and 482: 28.11 BRENT MCAFEE, P.ENG.I, Brent
Page 483 and 484: 28.13 MICHAEL CHIN, P.ENG.I, Michae
Page 485 and 486: 28.15 MICHAEL PAUL WISE, P.ENG., MB
Page 487 and 488: 28.17 CLAYTON RICHARDS, P.ENG.I, Cl
Page 489 and 490: 28.19 ALI FARAH, P.ENG.I, Ali Farah
Page 491 and 492: 28.21 S. (KUMAR) SRISKANDAKUMAR, M.
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