British Columbia

Mount Polley spill leads to new rules for tailing ponds

The disastrous collapse of the Mount Polley mine tailings pond in B.C.'s Interior last year has spurred changes to provincial environmental requirements for new mines with similar dams.

Companies have to enhance safety and cut the risk of dam failures

An aerial view of the Mount Polley mine tailings pond shows the area where the earthen wall gave way early on the morning of August 4. (Ministry of the Environment)

The disastrous collapse of the Mount Polley mine tailings pond in B.C.'s Interior last year has spurred changes to provincial environmental requirements for new mines with similar dams.

Developed in collaboration between the ministries of environment and mines, the new rules say mining firms must consider the possibility of a tailings disaster and evaluate the environmental, health, social and economic impacts of an accident.

Environment Minister Mary Polak said Thursday that companies currently under environmental assessment have been anticipating the changes.

"I think there's an understanding within the industry that after Mount Polley, the world has changed," Polak said. "We have to be able to assure the public that what's happening in the province for resource development is safe."

On Aug. 4, 2014, the massive dam storing tailings from the gold and copper mine gave way, spilling 24 million cubic metres of mine waste and water into nearby lakes and rivers.

Polak said the new requirements apply to all mining companies with applications currently under environmental assessment and are an interim measure while the Ministry of Mines completes a review of mining regulations.

The changes mean companies must include in their tailing management applications the best-available technologies and options for water balance to enhance safety and reduce the risk of a dam failure.

Potential risks

The Environmental Assessment Office will evaluate tailings management options and decide whether each mining company's plan adequately addresses potential risks.

Polak said the new requirements won't change the application process, but that most applicants will need to provide significantly more information and analysis.

Pending findings from two more investigations into the Mount Polley disaster — one by the Ministry of Mines and one by the B.C. Conservation Officer Service — could also lead to changes, Polak said.

"There will be all sorts of steps that will have to be taken following the Mount Polley incident."

The new regulations are based on the findings in the Mount Polley Independent Expert Investigation, prepared by a panel chaired by Norbert Morgenstern and released in January.

The investigation started weeks after the mine's tailings pond dam collapsed.

The report concluded the construction of the mine's tailings dam foundation on a sloping glacial lake deposit amounted to loading a gun and pulling the trigger.

Energy and Mines Minister Bill Bennett immediately ordered inspectors to check on similar dam foundations throughout the province.

Mining in B.C.

There are 98 permitted tailings storage facilities at 60 B.C. mines.

A spokesperson for Imperial Metals was unavailable for comment.

Karina Brino, president of the Mining Association of British Columbia, said her industry knew the investigation into the dam's collapse would inevitably mean regulatory and permitting changes.

"We are, obviously, as an industry, anxious to sit down with government and define how the whole package is going to be implemented," she said. "We're actually already looking at implementing some of those recommendations ourselves."


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