Feasibility Study and Technical Report - Pretivm

operating cost estimate include annual maintenance and replacement as required. It isrecommended that a trade-off study be done during the next phase of the project todecide on the most appropriate method of control in these areas.Alpine Solutions also recommends the following:• The area affected by icefall hazard at Path AR8 should receive constantmonitoring throughout the winter, and be regularly controlled using explosives tolimit the chance of large icefall events impacting a vehicle.• The segment of the access road which transits the Knipple Glacier should be reassessedon a regular basis due to the effects of glacial recession on avalancherunout distance on the glacier.• During winter, snow berms should be constructed in areas at the mine siteaffected by short slopes or avalanches to Size 2, in order to reduce thefrequency of small avalanches reaching facilities.• Transmission line structures (towers) should be located away from avalanchepaths in order to reduce the requirement for avalanche mitigation. If this is notpossible, additional analysis should be completed to determine the mostoptimal mitigation option. Mitigation may include designing towers foravalanche impact, diversion structures, or earthworks upslope of the tower.• The final design of the transmission line should involve collaboration with anAvalanche Specialist in order to optimize structure (tower) and conductorlocations.• Construction of the transmission line during avalanche season should includean avalanche management program to reduce risk to personnel andinfrastructure.• Any changes to layout of facilities and roads should be re-assessed foravalanche hazard.26.5.2 TRANSMISSION LINEValard reviewed the potential for a transmission line to the Project site, as a means toprovide electricity for mining operations. In comparing the transmission line to otherprojects in the area near the Project site, as well as other transmission line projects inthe area, Valard has the following recommendations:• Specialized steel structures should be used to allow for longer spans and limitthe number of structures. This will reduce the overall cost of the transmissionline, and allow for spanning of many snow avalanche areas along the route.• An active snow avalanche program should be used to manage the operationalrisk around snow avalanches to the transmission line. Snow avalanches,particularly on the east side of the Salmon Glacier valley, pose a risk to thetransmission line. An active snow avalanche program will likely be needed tocontrol the size and timing of snow avalanches during operations.Pretium Resources Inc. 26-6 1291990200-REP-R0012-02Feasibility Study and Technical Report on the BrucejackProject, Stewart, BC