Mount Polley: A Wake-Up Call to the Realities of Tailings Ponds
When a tailings pond broke at the Mount Polley gold and copper mine in south-central B.C., spilling millions of cubic metres of waste into a salmon-bearing stream, B.C. Energy and Mines Minister Bill Bennett called it an “extremely rare” occurrence, the first in 40 years for mines operating here.
He failed to mention the 46 “dangerous or unusual occurrences” that B.C’s chief inspector of mines reported at tailings ponds in the province between 2000 and 2012, as well as breaches at non-operating mine sites.
The Mount Polley tailings spill threatens two of B.C.’s most valued resources: salmon and water.
This spill was predictable. Concerns were raised about Mount Polley before the breach. CBC reported that B.C.’s Environment Ministry issued several warnings about the amount of water in the pond to mine owner Imperial Metals.
With 50 mines operating in B.C.—and many others across Canada—we can expect more incidents, unless we reconsider how we’re extracting resources.
Sudden and severe failure is a risk for all large tailings dams—Mount Polley’s waste pond covered about four square kilometers, roughly the size of Vancouver’s Stanley Park. As higher-grade deposits become increasingly scarce, mining companies are opting for lower-grade alternatives that create more tailings. As tailings ponds grow bigger and contain more water and waste than ever before, they also become riskier. The average height of a Canadian tailings dam doubled from 120 meters in the 1960s to 240 meters today. Alberta writer Andrew Nikiforuk likens increasing mining industry risks to those of the oil sands.
Open ponds of toxic slurry aren’t the best way to manage mining waste. Although there’s no silver-bullet solution, and more research funding on alternative technologies is needed, smaller underground mines are finding safer ways to deal with waste by backfilling tailings. Drying tailings or turning them to a paste before containment are two other options. Safer solutions cost more, making them less popular with profit-focused corporations. But surely B.C.’s $8-billion mining industry can afford to pay more for public and environmental safety.
The government allows the mining industry to choose the cheapest way to deal with waste, and companies often lack adequate insurance to cover cleanup costs when accidents happen. Imperial Metals admits its insurance will likely fall far short of what’s required to repair the damage at Mount Polley.
The mining industry and provincial and federal governments must do a better job of managing risks. But how can this happen when we’re facing unprecedented dismantling of Canada’s environmental regulations and decreased funding for monitoring and enforcement?