Mount Polley tailings disaster prompts inquiry and dam inspections

The B.C. government is taking strong action following the breach of a mine tailings pond at Mount Polley, near Likely in the Cariboo region of the province.

The breach from an open pit copper and gold mine occurred overnight on August 4. It sent an estimated 10 million cubic metres of water and 4.5 million cubic metres of slurry into Polley Lake and other waterways. The pond covered four square kilometres but was “virtually empty” four days later. Its spilled contents caused one creek to expand from 2 metres to 50 metres across, and caused Polley Lake to rise by 1.5 metres.

On August 18, the province’s Minister of Energy and Mines, Bill Bennett, ordered an independent engineering investigation and inquiry into the cause of the breach. The panel has to report back by January 31, 2015.

The same day Polak suspended the environmental assessment of a proposed copper-gold mine at Morrison pending the results of the investigation.

She also ordered that all mining companies must conduct a safety inspection for every tailings storage facility they operate. The inspections have to be reviewed by an independent, qualified, third-party professional engineer — “from a firm not associated with the tailings facility.”

The order will affect 60 metal and coal mines — both operating and closed — in B.C. The number of tailings impoundments involved is 98.

Under the province’s Health, Safety and Reclamation Code for Mines, annual safety inspections would normally have been due on March 31 next year. The new order accelerates the deadline, and it also establishes the requirement for an independent review.

The order also requires third-party reviews of the “dam consequence classification” by December 1 this year. This classification looks at the potential impacts if a dam should fail on nearby populations, the environment, cultural values and infrastructure.

The three experts appointed to the panel investigating the cause of the Polley Mine tailings pond breach are Norbert Morgenstern, Steven Vick of Colorado and Dirk Van Zyl, a professor at the University of B.C. The panel was appointed with the support of the Soda Creek and Williams Lake Indian Bands.

The results of the investigation are to be made public and, according to the government statement, their recommendations will be implemented where appropriate “to ensure such an incident never happens again.”

Van Zyl told the Globe and Mail that the Mount Polley disaster was “a dark day not only for mining in B.C., but worldwide.”

The Polley Mine is owned by Imperial Metals.

This article was corrected on August 21, 2014, 9.04 a.m. EDT