Three-and-a-half years after the Mount Polley Mine breach, the company responsible for the disaster is preparing to return water and tailings to the original tailings storage facility that failed in August 2014.
“We are going to start dredging the Springer Pit,” general manager Dale Reimer said on Feb. 21.
“We were mining in Springer Pit before the breach, and after the breach, we were using it to deposit all site contact water, plus the tailings from the mill.”
All of the water and tailings will be taken from the Springer Pit and sent through a pipeline, which is approximately three kilometres long, to be deposited into the repaired tailings pond.
“We mix the tailings with water and pump it down,” Reimer said, noting it is estimated in total about four million tonnes will be moved in total.
In advance of the release, the mine is doing water tests on the system, and if it works well and there are no “hiccups,” the dredging could start soon.
As for the continued discharge of water from the site into Quesnel Lake, Reimer said the mine’s water treatment plant is functioning for that purpose.
On average about 14,000 cubic metres of water goes into the lake a day.
“We are also continuing to mine in Cariboo Pit.”
When the tailings storage facility breached on Aug. 4, 2014, an estimated 10.6 million cubic metres of supernatant water, 7.3 million cubic metres of tailings solids, 0.6 million cubic metres of construction material and 6.5 million cubic metres of interstitial water was released.
The release caused physical impact to the downstream environment, including Polley Lake, Hazeltine Creek and Quesnel Lake.