One month after the tailings pond breached at the Mount Polley mine near Likely, B.C., the mine's operator now says the amount of contaminated water and waste that spilled into the ecosystem was nearly twice as much as originally estimated.

After the dam burst on Aug. 4, the initial estimates were that 10 million cubic metres of wastewater plus more than four million cubic metres of sediment spilled into Polley Lake, eventually washing down Hazeltine Creek into nearby Quesnel Lake.

Imperial Metals now says nearly 25 million cubic metres of contaminated water and mine waste spilled into surrounding waterways, about 78 per cent more than the first estimates. That total includes:

  • 10 million cubic metres of water.
  • 13.8 million cubic metres of tailings slurry.
  • 0.6 million cubic metres of construction waste from the dam.

But the company's vice-president of corporate affairs, Steve Robertson, said repeated testing has proven the water in the area is safe to drink, and he's been drinking it while living in nearby Likely.

Robertson said cleanup and restoration efforts in Quesnel Lake and Polley Lake are ongoing, but engineers need to sign off on the safety of the Hazeltine Creek area before the company can begin work there.

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