Mt Polley Mine Requests Discharge Bypass

October 2020 Mt Polley requests approval to bypass their water treatment facility and discharge directly into Quesnel Lake via the QL pipeline.

...The Mount Polly Mine has an annual net water surplus, and discharge from the mine site is necessary to manage mine site water. As described in the Tailings Storage Facility Detailed Design to Elevation 970 m report (Golder 20151), the TSF is used for temporary detention and attenuation of large freshet flow rates; however, the fundamental basis of the water management plan is to not accumulate water on site (including the TSF) by discharging water, and to not carry over water from year to year even under extreme wet conditions. Accumulation of water in the TSF or the site in a year over year basis increases the risk to the TSF as it reduces the capacity at the site to manage runoff from extreme flood events....