Feasibility Study and Technical Report - Pretivm

• fuel storage• vendors’ instrumentation packages.An automatic sampling system will collect samples from various product streams foronline analysis and daily metallurgical balance.Particle-size-based computer control systems will be used to maintain the optimum grindsizes for the primary grinding and concentrate regrinding circuits. Particle-size analyzerswill provide main inputs to the control system.Remote MonitoringCCTV cameras will be installed at various locations throughout the plant, such as thecrusher conveyor discharge point, the SAG surge feed conveyer, the SAG and ball millgrinding area, the flotation area, the regrind area, the paste plant, the gold room, theconcentrate handling building, and the tailings handling facilities. The cameras will bemonitored from the plant control rooms.18.15 POWER SUPPLY AND DISTRIBUTIONA BC Hydro 138 kV overhead power line will supply power to the Project site.The main site power will be stepped down from 138 kV to 4.16 kV via two15/20/25 MVA oil-filled transformers, complete with neutral grounding resistors, locatedin the main substation yard. Each transformer is capable of carrying the entire site load.A pre-fabricated electrical house (e-house), containing 5 kV class switchgears, willdistribute power to various points on the site.The main mill and underground loads will be fed via power cables in cable tray. Thesubstation location is at a significant elevation above the mill; therefore, the proposedpower cable routing will descend several benches from the substation then follow onebench to both the portal and mill building areas. A cable bridge will be constructed tospan from the bench to the mill building allowing for safe clearance and free traffic flowbelow.Within the mill, large loads will be powered at 4.16 kV. Smaller loads will be powered at600 V via switchgear and MCCs. Variable frequency drives and soft starters will beemployed strategically to optimize process and energy performance.Approximately 1.6 km of 4.16 kV single wood-pole overhead power lines will beconstructed to provide power to outlying buildings such as the water treatment plant, fuelstorage, operations camp, etc.The emergency power strategy will employ two elements:• Four existing 500 kW, 600 V diesel generators will be installed at the mainsubstation and will connect to the main power distribution bus. Although thePretium Resources Inc. 18-41 1291990200-REP-R0012-02Feasibility Study and Technical Report on the BrucejackProject, Stewart, BC