Mt. Polley Mine, site of Canada’s worst spill, is back in limited operation and seeking permits to return to full operation as one expert forecasts a dozen similar, serious failures by 2020 that could cost upward of $6 billion in damages.
In August 2014, Mt. Polley, a gold-andcopper mine owned by Imperial Metals Corp., Vancouver, dumped 4.5 billion gallons of water and 10.3 million cu yd of tailings and construction waste into Polley Lake, Hazeltine Creek and Quesnel Lake, which feeds into British Columbia’s Fraser River, endangering the area’s drinking water and, possibly, waters where salmon spawn.
The drinking water has been declared safe and continues to be monitored, but the long-term effects on wildlife and the environment still are being studied.
The Polley incident won’t be the last big blowout of a tailings storage facility (TSF), says David Chambers, a mining specialist and president of the Center for Science in Public Participation, Bozeman, Mont.
In their report, Chambers and Lindsay Newland Bowker, risk analyst and head of Bowker Associates, Stonington, Maine, say the Mt. Polley spill and others are occurring more often, getting bigger and becoming more costly to governments— and their taxpayers—worldwide.
“Water management is an important part of these accidents. Ponds are being used to store excess amounts of water,” Chambers said. The experts who studied the Mt. Polley spill noted “tailings dams fail, on average, 10 times the rate of water dams,” he said. “If you operate tailings dams the same as water [dams], you could cut the failure rate by 10.” Chambers and Bowker, who studied decades of mine spills, also found that, generally, “the public is stuck with the cleanup cost.”
British Columbia requires mining companies to post a reclamation security, said David Haslam, Ministry of Mines spokesman. Mt. Polley has put up $20.5 million, and Red Chris Mine, Imperial’s controversial new mine, has posted $12 million.
Mt. Polley reclamation and rehabilitation work will cost an estimated $67.4 million, says spokesman Steve Robertson.
Hazeltine Creek, about 6 ft wide before the spill and gaping at 160 ft after, has been rebuilt and replanted by company and contract crews, including First Nations workers, Robertson said.
They removed more than 154,300 tons of dirt and mining waste to the TSF from the creekbed. They also brought in more than 460,000 tons of rock to build a new creek channel and banks, which were lined with more than 36,000 cu yd of mulched trees destroyed by the spill, Robertson said.
The province has paid about $6 million for inspection, testing, monitoring and related costs and is seeking $626,645 under Spill Cost Recovery regulations, said David Karn, spokesman for the Ministry of Environment. Imperial has proposed a repayment plan schedule, he said.
The Imperial Metals has completed its phase-one remediation work, dealing mainly with water quality and elimination of health and environmental impacts. It’s now working on phase two, which involves remediation through a summer 2016 deadline, as well as into the future, Karn said.
“Full environmental remediation will take years,” so a cost estimate is difficult, Karn added.