Pretium Resources reported that commissioning is under way at its high-grade, underground Brucejack gold mine in northwest British Columbia and that the mine will reach commercial production before year-end 2017. Brucejack is scheduled to produce an average of 504,000 ounces per year (oz/y) of gold over its first eight years of operation and a mine-life average of 404,000 oz/y over 18 years.
The Valley of the Kings portal building will serve as the primary access point to convey gold ore from the under-ground crusher to the mill.
Capital cost to complete the Brucejack project is now estimated at $811.1 million. The feasibility study for the project, completed in June 2014 and updated in December 2016, considers only the project’s Valley of the Kings deposit, which hosts proven and probable reserves of 8.1 million oz of gold in 15.6 million metric tons (mt) grading 16.1 grams/mt gold.
The study describes a path to production for a 2,700-mt/d underground mine. Stopes will be mined using a combination of longitudinal and transverse mining, depending on zone width and orientation. Cemented paste tailings will be prepared in a paste plant on surface near the mill and pumped underground for distribution to the stopes.
As of early February, underground development was well advanced, with 11 stopes crosscut on two levels in preparation for long-hole drilling. Crosscutting of a further four stopes was in progress. Long-hole drills were being mobilized, with long-hole drilling expected to begin in the second week of March. Construction of underground infrastructure, including the crusher, conveyor and transfer tower, was ongoing.