Feasibility Study and Technical Report - Pretivm

16.0 MINING METHODS16.1 GENERALThe proposed underground mine design supports the extraction of 2,700 t/d of orethrough a combination of transverse LHOS and longitudinal LHOS. Paste backfill isintegral to the mine plan to maximize both orebody recovery and mining productivity.Modern trackless mobile equipment will be employed in the majority of mining activities.A main decline from a surface portal in close proximity to the concentrator will be used toaccess the mine. A second decline, parallel to the main access decline, will be dedicatedto conveying crushed ore directly to the concentrator via a 650 m long conveyor. Theexisting West Zone portal will also provide access (and egress) to the mine, although thisroute will not generally be required for day to day operations.A fleet of LHDs and trucks will be used for material loading and transport from thevarious underground working areas through an internal ramp system that connects alllevels to the centrally located crusher.Permanent fans will provide ventilation by forcing air down the declines, through theinternal ramps, and exhausting to surface via dedicated raises that connect the variousworking levels to surface in each zone. The primary fans will be located at each of themain surface portals, and complemented by booster fans located in the exhaust raises,in a common push-pull configuration. An electric mine air heating system will be used totake advantage of low electricity prices, with a propane system available as a back-up.A pre-production development program that attains approximately 660 m/mo of advancewill be required to establish the mine infrastructure and provide access to the initialstoping levels during the first two years of underground activity. Ongoing development, tosustain 2,700 t/d of ore production, will average approximately 475 m/mo during thefirst half of the mine life, and then decrease to approximately 275 m/mo in later years.Major underground infrastructure will include crusher, conveyor belt, ventilation raises,fans, heating system, pumping stations, a maintenance facility, electrical substations, afuelling facility, explosives magazines, refuges, mine communications and other ancillaryinstallations.Pretium Resources Inc. 16-1 1291990200-REP-R0012-02Feasibility Study and Technical Report on the BrucejackProject, Stewart, BC