A massive dam breach that spilled billions of gallons of mining waste into lakes and rivers in western Canada is still being investigated, but early results have alleviated some concerns.
The environmental disaster at Imperial Metals’ open pit copper and gold mine on Mount Polley, almost 400 miles northeast of Vancouver, saw the dam of its tailings pond break on Aug. 4. A torrent of grey sludge widened the adjacent Hazeltine Creek to a river; the sludge made its way to pristine Polley and Quesnel Lakes, important to pacific salmon spawning runs.
The size of the dam alone was enormous. A bulldozer sitting atop the dam looks like an ant compared to the massive wall of dirt and rock that was supposed to hold in the byproducts of mining operations there. The pond itself is the size of Central Park.
Imperial Metals has been accused of not properly maintaining the dam. A former Imperial foreman told the Vancouver Sun that an engineering firm hired to monitor the construction of the pond directed the dam be reinforced with five and a half million tons of rock. He estimates a little over one million tons was actually used.
The immediate impacts of the spill are quickly passing. On Tuesday health authorities cancelled water warnings covering much of the affected area proclaiming the water safe to drink and fish safe to eat. A much smaller area where a plume of sediment is still visible remains under restrictions however.
First Nation communities in the area are concerned the fish will require longer-term testing to be certain they are not contaminated with heavy metals or other residues from the tailings pond. Two native communities have elected not to fish the area this year.
Al Richmond, chair of the Cariboo Regional District, said the breach cannot be safely investigated yet and it is too early to know the exact cause.
“Everybody would like to get investigation underway right away, but it’s difficult to do.”
Richmond said they do not want to put people at risk because the area is a large swath of unstable mud.
While it is encouraging that daily water tests are coming back clean, he said the long-term impacts remain unknown.
The Ministry of Environment is testing the sediment that was released and those results are expected Saturday. Whatever is in the sediment will have a longer-term impact on the immediate environment.
The Department of Fisheries and Oceans is still testing fish. Richmond said they would be a need to monitor salmon runs to learn the long-term impacts of the breach.
With the worst of the spill now passed, local residents have a new worry—jobs. The breach has forced Imperial Metals to suspend normal operations, affecting about 380 workers. Forty-two workers have already been dismissed and the others are working on the clean up.
While cleanup costs are unknown, they are widely believed to be hundreds of millions of dollars beyond the company’s reported $15 million insurance policy.
The president of the workers union the affected employees belong to told CBC on Thursday the fate of the mine was uncertain.