Mount Polley Mining Corporation will be hosting a phone-in session on Thursday, Dec. 8, about its treated water discharge plan.
Residents from the region will receive a letter in the mail inviting them to dial in and a two-page back-grounder which the mine’s chief operating officer Don Parsons shared during a presentation to the Cariboo Regional District board last Friday.
Parsons said the mine is applying for the highest water discharge rate possible for limited periods of time to be better able to manage periods of high flow such as at spring freshet so the water is not stored in large amounts in the tailings impoundment.
Most of the water the mine had not received a permit to discharge was released as a result of the August 2014 tailings impoundment breach at Mount Polley, Parsons added.
“On an average year, with the rain fall we get, there are six million cubic metres of water to be released annually,” Parsons said, noting in a wet year that amount is 9.4 million cubic metres. “We have to have some sort of discharge plan.”
There has always been the intention to release water from the site into environment and nearby watersheds, including Quesnel Lake, Parsons said, referring to the mine’s original environmental assessment certificate issued in 1996.
Since December 2015, the mine has been discharging treated water into Quesnel Lake.
It is discharged into the new Hazeltine Creek channel, and carried to sedimentation ponds where it flows into two buried pipes and is discharged through diffusers into Quesnel Lake at 45 metres and 50 metres below the surface.
Area J director Xeni Gwet’in Chief Roger William told Parsons many people have concerns about any effluent from a mine going into nearby watersheds.
“Can the company reuse the water so that nothing is going out of the mine, is the treated water safe to drink, how safe are the fish in Polley Lake, and is there history on the water treatment system and its impacts if any on people?” William asked.
Parsons responded that he has been eating fish out of Polley Lake.
The water treatment plant was developed in Quebec, and is a type used world-wide.
“It is effective at taking out the suspended solids, which is what the biggest concern is at Mount Polley because that’s where most of the metals reside.”
Area B director Jerry Bruce voiced the concerns of the Quesnel Lake community that the lake is being damaged.
“My understanding is that Quesnel Lake is an international resource. It’s an inland fjord that is very, very deep and one of the largest in the world,” Bruce said. “When I look at the whole lake, and the stuff you’re putting into it, what portion of the lake are you actually affecting?”
Parsons said through the company’s water monitoring they cannot detect the discharged water in the lake outside 100 metres of the diffusers.