Imperial Metals cleared to restart full production at ill-fated Mount Polley mine

TORONTO (miningweekly.com) – The British Columbia government on Thursday gave the owner of the now infamous Mount Polley copper/gold mine the thumbs up to restart full production.

The August 2014 Mount Polley mine disaster, considered the worst mine disaster in Canadian history, released more than 25-million cubic metres of mine waste into the Fraser river watershed.

Owner Imperial Metals and subsidiary Mount Polley Mining Corporation would now resume production using the repaired and strengthened tailings storage facility (TSF) to manage tailings.

The permit amendment authorised Mount Polley Mining to continue operations in previously permitted areas of the Cariboo pit and underground workings. Under the permit amendment the mine was authorised to process up to 22 450 t/d of ore and store tailings in the repaired and strengthened TSF, the provincial government advised.

Before receiving the permit amendment, the application underwent a lengthy review process including a geotechnical review, a 30-day public consultation period and a detailed technical review by members of the mine development review committee (MDRC). The MDRC comprised representatives from provincial agencies, First Nations, local governments (the city of Williams Lake and the Cariboo regional district), the community of Likely, the Department of Fisheries, and Oceans and Environment Canada.

The geotechnical review found that the proposed design and construction of the repaired TSF met appropriate engineering standards for tailings facilities. It also found that the recommendations from the independent expert panel and Chief Inspector of Mines investigations were adequately taken into consideration for the design and operation of the repaired and reinforced TSF.

The British Columbia government had previously issued a restricted restart permit amendment on July 9, 2015, under which Mount Polley Mining had the obligation to submit a draft technical assessment report in support of the long-term water management plan to government by June 30, to continue operations.