Feasibility Study and Technical Report - Pretivm

HAULAGE TRUCKSAMC considered electric haulage trucks in the interest of minimizing ventilation airflowand heating requirements. The significant capital premium for equipping the mine withan electric fleet was found to be irrecoverable through reduced operating costs, such thatstandard diesel units were adopted for all haulage activity. Six units will be required tosupport the scheduled material movement of ore and waste.Forty tonne trucks were determined to be the most cost effective truck capacity inconsideration of utilization, capital cost and operating costs.BOLTERSPattern bolting of development headings and stope backs will utilize both 2.4 m resingrouted rebar and 2.4 m swellex type friction bolts. Two units will be required forredundancy and should be equipped for the installation of either bolt type.CABLE BOLTERSAll stope undercuts and overcuts will be cable bolted with 6 m long cable bolts, and allintersections will be bolted with 5 m long cable bolts. A single bolter could be utilized;however, the utilization would be higher than 90% and it is likely that headings wouldstand waiting. Two cable bolters have been factored into the study.LONG HOLE DRILLSProduction drilling will mostly be done with ITH hammer drills. Compared to top-hammerdrills, ITH drills are more accurate for longer holes and are recommended for the 25 maverage production hole length. The proposed Cubex Aries B drill is also able to ream762 mm diameter slot raises, thus eliminating the need for a standalone slot raisemachine or crew. This drill will also be utilized for service holes between sublevels.In addition to the ITH drills, a single top hammer drill will be used. This will provide someflexibility to the production drilling fleet. The top hammer drill will be utilized for sillrecovery, crown level stopes, stopes near the Brucejack fault where fan drilling isrequired (full width slashing is not anticipated for these stopes), and the recovery ofresources at the top of lenses where uphole drilling is inevitable. One unit will berequired.EXPLOSIVE LOADERSTwo face chargers will be required for development loading, to load as many as sixrounds per day. Each unit will require pumps for face charging with emulsion. One unitwill be required at full production for loading uphole and downhole stopes with emulsion.SHOTCRETE SPRAYERSIt is anticipated that 10% of development will require shotcrete. Shotcrete will also berequired for paste fill exposures in stope development and barricade construction forbackfilling and ventilation bulkheads. Two units will provide adequate capacity andredundancy for this critical activity. Wet fibre-reinforced shotcrete will be standard.Pretium Resources Inc. 16-42 1291990200-REP-R0012-02Feasibility Study and Technical Report on the BrucejackProject, Stewart, BC