Feasibility Study and Technical Report - Pretivm

There may be opportunities to optimize the underground development design andschedule. Further geotechnical and hydrogeological studies will better define groundcontrol and dewatering requirements.The study should be advanced to the detail design and construction stage.25.4 PROJECT INFRASTRUCTURE25.4.1 AVALANCHE HAZARD ASSESSMENTAn avalanche hazard assessment was completed for the Project. Facilities and accessroutes are exposed to approximately 15 paths or areas. Avalanche magnitude variesbetween Size 2 and 4, and frequency varies between annual and 1:100 years. Potentialconsequences of avalanches reaching the Brucejack mine facilities, transmission line,worksites, and roads include damage to infrastructure, worker injury (or fatality), andproject delays. Potential consequences of static snow loads on transmission towersinclude damage to towers and foundations, and potential loss of electrical service to themine. Without mitigation to the effects of avalanches and static snow loading, there is ahigh likelihood of some of these consequences affecting operations on an annual basis.Avalanche mitigation for the Project includes location planning in order to avoidplacement of facilities in avalanche hazard areas. For areas where personnel andinfrastructure may be exposed, an avalanche management program will be implementedfor mine operations during avalanche season (October through June). The program willutilize an Avalanche Technician team to determine periods of elevated avalanche hazardand provide recommendations for closures of hazard areas. The options for reducingcontrol include explosive control, or waiting for natural settlement. Areas that areexpected to have increased frequency of hazard and consequences will be evaluated forthe installation of the RACS in order to allow for avalanche explosive control duringreduced visibility (darkness and during storms). An allowance has been made in thecapital and operating cost estimates for six RACSs.25.4.2 TRANSMISSION LINEValard reviewed potential routes and developed an initial design for the transmission lineto the Project site. Based on Valard’s considerable experience in construction oftransmission lines, as well as the experience gained from the two significant transmissionprojects very near the Project site, Valard identified a transmission line route from LLHnorthwards up the Salmon Valley to the Knipple Glacier, and then high on the slopesabove the glacier to the Project site. Based on this route, Valard has the followinginterpretations and conclusions:• The preferred route for the transmission line is along the moderate slopes onthe west side of the Salmon Glacier valley. These slopes have exposed or nearsurface bedrock along most of the route, along with short and sparse tree cover.No harvesting activities exist in the area.Pretium Resources Inc. 25-2 1291990200-REP-R0012-02Feasibility Study and Technical Report on the BrucejackProject, Stewart, BC