Feasibility Study and Technical Report - Pretivm

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13.3.11 CONCLUSIONSA review of preliminary test work on samples from the Brucejack deposit has led to thefollowing conclusions:• The Brucejack mineralization is moderately hard.• The test results suggest that the mineralization is amenable to thegravity/flotation combined recovery process. The recovery flowsheet shouldinclude: gravity concentration to recover coarse free gold and silver flotation to produce rougher and scavenger concentrates regrinding on the rougher and scavenger concentrates gravity concentration to recover fine free gold and silver cleaner flotation to produce a final concentrate for sale smelting on gravity concentrate to produce gold/silver doré.• The test results indicate that there is a significant variation in the metallurgicalperformance of mineral samples taken from different parts of the deposit.• The test results show that flotation concentrate responds reasonably well todirect leaching using cyanide, excluding a few of samples containing highergraphite (carbon), arsenic, or electrum content. The cyanide leaching conditionshave not yet been optimized.Further improvements should be evaluated for gold and silver recoveries,including oxidation pre-treatment.• The gravity concentrates responded very well to intensive leach by cyanide.13.3.12 RECOMMENDATIONSFurther test work is recommended to:• Conduct large scale pilot plant tests to confirm the findings of the test workcompleted to date.• Further investigate the response of the sample material to the cyanide leachprocess.13.4 METALLURGICAL PERFORMANCE PROJECTIONThe proposed flowsheet used for the current study will include a gravity/smelting andflotation process, to produce gold-silver doré and a flotation concentrate containing goldand silver. The metallurgical performance of the Brucejack mineralization has beenprojected according to the results generated from the locked cycle and variability tests.Pretium Resources Inc. 13-53 1291990200-REP-R0012-02Feasibility Study and Technical Report on the BrucejackProject, Stewart, BC
There is significant variation in metallurgical performance, which is possibly due tonugget effects; therefore, the projections were based on average data, summarized asfollows:• The gold and silver recoveries reporting to gold-silver doré were projected basedon the gravity concentration test results, GRG gravity circuit simulations, andexperience. It was assumed that the smelting recovery is 99.5%. The slag fromsmelting will be ground and tabled to recover gold-silver alloy grains, and thetable tailings will be blended with the flotation concentrate.• The gold and silver recoveries reporting to the gold-silver flotation concentratewere estimated using the average locked cycle test results achieved at a primarygrind size of 80% passing approximately 75 µm, and the regression equationsthat were derived from the plots of the variability test results.• The flotation concentrate grade was estimated by the sulphur grade of theconcentrates produced from the locked cycle tests.For materials with head grades beyond the range of the tested heads, the metal recoveryand concentrate grade estimates were assumed based on test results and experience.The projections are detailed in Table 13.36 for the VOK Zone mineralization and Table13.37 for the West Zone mineralization.Table 13.36Head Grade(g/t)Metallurgical Performance Projection – VOK ZoneGold and Silver Recovery(%)Doré - Gold< 0.5 = 00.5 to 9.99 = - 0.147*((Head Grade, g/t) 2 ) + 5.68*(Head Grade, g/t) - 1.2149.99 to 40 = 7.32*ln(Head Grade, g/t) + 24.012> 40 = 52Doré - Silver 400 = 1.0Flotation Concentration - Gold< 0.5 = 300.5 to 5.64 = 85.44*(Head Grade, g/t) 0.056 + 0.147*(Head Grade, g/t) 2 - 5.68*(Head Grade, g/t) + 2.65.64 to 9.99 = 1.18*ln(Head Grade, g/t) + 0.147*((Head Grade, g/t) 2 ) - 5.68*(Head Grade, g/t) + 94.6949.99 to 40 = - 6.14*ln(Head Grade, g/t) + 69.558> 40 = 46.5Flotation Concentration - Silver< 3.0 = 353.0 to 130 = 2.793*ln(Head Grade, g/t) - (34.643*((Head Grade, g/t) - 0.48 )) + 78.07130 to 400 = 90.5> 400 = 91.5Pretium Resources Inc. 13-54 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
Page 127 and 128: Year Program ID Laboratory ** Gravi
Page 129 and 130: 13.3.2 2012 TO 2013 TEST SAMPLESIns
Page 131 and 132: Table 13.7 Conceptual Master Compos
Page 133 and 134: ALSInspectorateFire Assay (g/t) Met
Page 135 and 136: 13.3.6 ORE HARDNESS TEST WORKTable
Page 137 and 138: Table 13.14 Sample Specific Gravity
Page 139 and 140: In general, there was a reduction i
Page 141 and 142: Figure 13.5 Effect of Primary Grind
Page 143 and 144: In 2012 and 2013, most of the flota
Page 145 and 146: Further cleaner tests were conducte
Page 147 and 148: Figure 13.14 Effect of Cleaner Flot
Page 149 and 150: SampleIDWZ-2CompositeCompositeBJ-AC
Page 151 and 152: The 2012 and 2013 tests routinely i
Page 153 and 154: Figure 13.17Cumulative Stage GRG ve
Page 158 and 159: Figure 13.21 Silver Cyanide Extract
Page 160 and 161: Table 13.24 Head Sample Cyanidation
Page 162 and 163: Based on the findings of the prelim
Page 164 and 165: Primary Grind/Regrind SizesConcentr
Page 166 and 167: Further cyanide leach tests were ca
Page 168 and 169: including samples with low head gra
Page 170 and 171: Grade (g/t) Recovery/Extraction (%)
Page 172 and 173: Figure 13.28 Variability Test Resul
Page 174 and 175: Table 13.31Locked Cycle Tests Resul
Page 176 and 177: Table 13.33Conventional Thickening
Page 180 and 181: Table 13.37Head Grade(g/t)Metallurg
Page 182 and 183: • geological interpretation and m
Page 184 and 185: to form a series of seemingly strat
Page 186 and 187: 14.6 COMPOSITING OF ASSAY INTERVALS
Page 188 and 189: In the high-grade domains (includin
Page 190 and 191: Table 14.3Parameters to Describe Go
Page 192 and 193: 14.8.3 HIGH-GRADE DOMAINS - PROBABI
Page 194 and 195: analysis. Any target blocks that re
Page 196 and 197: For VOK and West Zone the interpola
Page 198 and 199: Table 14.9Comparison of the Mean Co
Page 200 and 201: the economic viability of the depos
Page 202 and 203: 14.15 RESOURCE REPORTINGThe mineral
Page 204 and 205: 15.0 MINERAL RESERVE ESTIMATES15.1
Page 206 and 207: Table 15.1Net Smelter Return Parame
Page 208 and 209: 15.4 MINING SHAPESAMC used the Mine
Page 210 and 211: Strike length varies considerably w
Page 212 and 213: 15.7 MINERAL RESERVESMineral reserv
Page 214 and 215: Figure 15.4Reserve Shapes and Minin
Page 216 and 217: 16.2 MINE DESIGN16.2.1 ACCESS AND R
Page 218 and 219: Figure 16.2Brucejack Twin Declines
Page 220 and 221: Figure 16.4Typical Level Plan - 1,2
Page 222 and 223: Table 16.1Development Design Parame
Page 224 and 225: Figure 16.7Mineable Stope Shapes -
Page 226 and 227: 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
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• small tools• consumables• c
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The total cost for Major Area 33 -
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The unit cost estimates are based o
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MINE OPERATING COSTSThe total under
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Table 21.7Summary of Process Operat
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Table 21.8Summary of Backfilling Op
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DescriptionLabourForceTotal Cost($/
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22.0 ECONOMIC ANALYSIS22.1 INTRODUC
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Figure 22.1Pre-tax Cash FlowCumulat
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transport the concentrate to a buil
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Figure 22.4Pre-tax Payback Period S
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Canadian development expense and 60
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23.0 ADJACENT PROPERTIESSnowden not
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23.2 HIGH PROPERTYThe Teuton Resour
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managers, and the mining manager, a
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MANAGEMENT PROCEDURESThe EPCM contr
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Figure 24.2Level 1 Execution Schedu
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Capital equipment purchases will be
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Construction work will be split int
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provided with dedicated emergency p
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econciliation to the freight consol
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PROJECT TEAM RESPONSIBILITIESIt is
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WBS Area PretivmEPCMTeamUnderground
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24.1.15 RISK MANAGEMENTA Risk Asses
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There may be opportunities to optim
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The conceptual layout is preliminar
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25.4.8 TAILINGS DELIVERY SYSTEMThe
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26.0 RECOMENDATIONS26.1 GEOLOGYThe
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• Further test work to identify t
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The estimated cost for the above-me
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• Careful planning as well as det
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26.5.6 BRUCEJACK OUTLET CONTROL STR
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• Further groundwater quality and
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27.0 REFERENCES27.1 AVALANCHE HAZAR
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Price, W. (2005). Mend Report 9.1c:
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Britton, J. M. and Alldrick, D. J.,
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Olssen. L., Jones, I.. 2012b. Preti
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28.0 CERTIFICATES OF QUALIFIED PERS
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28.2 IVOR W.O. JONES, M.SC., CP, FA
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28.3 JOHN HUANG, PH.D., P.ENG.I, Ji
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28.5 HAMISH WEATHERLY, M.SC., P.GEO
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28.7 SABRY ABDEL HAFEZ, PH.D., P.EN
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28.9 CATHERINE SCHMID, M.SC., P.ENG
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28.11 BRENT MCAFEE, P.ENG.I, Brent
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28.13 MICHAEL CHIN, P.ENG.I, Michae
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28.15 MICHAEL PAUL WISE, P.ENG., MB
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28.17 CLAYTON RICHARDS, P.ENG.I, Cl
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28.19 ALI FARAH, P.ENG.I, Ali Farah
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28.21 S. (KUMAR) SRISKANDAKUMAR, M.
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