North America: Copper Mountain mine

This open pit copper mine near Princeton, British Columbia, resumed production in 2011 after the mine’s 1996 suspension.

 

A permit condition of resumption was the segregation and separate management of waste rock with potential for acid rock drainage even though ARD had not been seen at the site during a century of mining. Any potentially acid-generating (PAG) rock remaining after mining was to be re-handled, used as backfill, and covered with water to prevent oxidisation.

 

Since the reopening, SRK has annually helped interpret monitoring data collected as part of waste rock and tailings management plans. Samples of non-PAG rock confirmed its non-acid-generating characteristics, and samples of PAG waste rock indicated low ARD potential.

 

Through a statistically-designed sampling program, SRK confirmed its observation that while bulk rock could be PAG, blast fines were consistently non-PAG. Based on this, our client asked for its permit segregation requirement to be removed. The government approved this provided an enhanced monitoring program was designed with alert levels specified for segregation resumption.

 

Increasing waste rock placement options and decreasing re-handling have reduced operation costs.