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Seven Years after Mount Polley Disaster, Mine Waste Still Flows into Quesnel Lake

Seven Years after Mount Polley Disaster, Mine Waste Still Flows into Quesnel Lake

A ‘temporary’ permit allows wastewater to be dumped in the water. That may not change anytime soon.

Doug Watt was sleeping the night the Mount Polley mine’s tailings dam released, dumping its contents into Hazeltine Creek, which flows into the west arm of Quesnel Lake near his home in Likely, B.C.

It was the early morning of Aug. 4, 2014, and Watt, who lives about seven kilometres from the mine site, says he wasn’t aware of the breach until a 6:30 a.m. call from the local fire and rescue service woke him. The first thing he noticed was the sound.

“It was quite a shock,” he says. “We went outside, and you could hear it down the lake. It sounded like a distant Niagara Falls.”

The gold and copper mine deposited nearly 25 million cubic metres of mine waste into the Fraser watershed that day — roughly equal to the volume of water flowing over Niagara Falls every two-and-a-half hours. It left a toxic slurry that remains on the lakebed today. Data showed the lake rose several inches overnight, Watt says.

Seven years later, mine waste continues to flow from Mount Polley into Quesnel Lake under a permit issued by the B.C. government.

That permit was meant to be temporary, a stopgap measure to prevent another spill while mine owner Imperial Metals developed long-term wastewater solutions.

Now a local citizen’s group is fighting proposed amendments that could allow mine waste dumped into Quesnel Lake well into the future.

…click on the above link to read the rest of the article…

Mount Polley spill blamed on design of embankment

Mount Polley spill blamed on design of embankment

Independent investigation finds foundation of earthen dam failed because of unstable underlying layers

An independent investigation has determined the breach of the Mount Polley mine tailings dam in B.C. was caused by a failure to detect a weak layer in its foundation, likening the massive embankment to a “loaded gun.”

The report, which was released on Friday morning in Victoria, said the design failed to take into account the complexity of the instability of underlying glacial and pre-glacial layers under the retaining wall.

But the authors, geotechnicians Norbert Morganstern and Steve Vick, did not blame provincial inspectors for not detecting the problem beforehand.

The investigators said the dam was built on a weak layer of glacial deposits that was undetected at the time, making the dam like a ‘loaded gun.”

They said the construction of a steep slope in the embankment as the dam was raised was “like pulling the trigger,” causing the failure last summer.

They also concluded that massive volume of water in the tailings dam did not cause the dam to fail, but it did result in more tailings being released when it did breach.

Just eight days before the dam failed, a plan was approved to raise the dam further, but on the condition that a buttressing wall was put in place and the slope decreased, they said.

The investigators also made several recommendations to improve the safety of tailings dams, including updating the way they are designed, monitored and regulated in B.C.

…click on the above link to read the rest of the article…

 

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