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Tailings pond breach at Mount Polley Mine in B.C.

News | August 6, 2014 | By:

Unlined pond fails, pours effluent into nearby waterways.

On Monday, Aug. 4, 2014, the tailings pond of the Mount Polley Mine burst, spilling toxic effluent into nearby Polley Lake and Quesnel Lake, and depriving residents of Likely, B.C., and surrounding areas of fresh water for household use.

This area is located in the Cariboo region of central British Columbia, situated where the west arm of Quesnel Lake empties into the Quesnel River, about 90 miles south of Prince George, B.C., 30 miles northeast of Williams Lake, B.C.

Boyd Ramsey, GSE chief engineer and chairman of the Executive Council of the Geosynthetic Materials Association (GMA), said that the Mount Polley failure is remarkably similar to the 2008 Kingston, Tenn., coal ash containment pond disaster, but with mine tailings-the refuse from the gold and copper mining processes at Mount Polley.

(In Kingston on Dec. 22, 2008, a 40-acre impoundment pond containing coal ash slurry from the adjacent power plant broke, spilling more than 1 billion U.S. gallons of waste into the surrounding land and waterways.)

In both the Kingston and Mount Polley failures, the containment reservoirs were not lined. Asked for comment about the Mount Polley facility failure, Ramsey replied: “A geosynthetic lined and reinforced system could have prevented this.”

Reports say that Canada’s National Pollutant Release Inventory shows that owner, Vancouver, B.C.–based Imperial Metals Corp., was disposing of arsenic, lead, and mercury, among other chemicals, as mining by–products at the Mount Polley facility last year.

The company, which also operates a gold mine in Nevada, said the tailings discharge was stabilized; however, the cause of the breach and the exact quantity of discharge has yet to be determined.

“Our first priority is the health and safety of our employees and neighbors, and we are relieved no loss of life or injury have been reported,” said a statement from Imperial Metals on Tuesday. “We are deeply concerned and are working to mitigate immediate effects and understand the cause.”

The company also said, “Monitoring instruments and onsite personnel had no indication of an impending breach.”

However, several news reports reference an environmental consultant who examined the Mount Polley Mine tailings pond who says the storage facility was growing at an unsustainable rate.

He said Imperial Metals was building the walls of the storage dam higher and higher to hold back the contaminated water, and was seeking a permit to treat and release some of the water to keep the size of the pond in check.

–compiled and edited by Geosynthetics magazine

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