Mount Polley takes water quality very seriously. Extensive monitoring is evidencing the effectiveness of the remediation and site water management programs undertaken by Mount Polley.
How is water quality monitored in Polley and Quesnel Lakes to ensure proper environmental monitoring is being carried out?
- Mount Polley follows the BC-ENV approved Comprehensive Environmental Monitoring Plan. The results for all our monitoring sites are published in the publicly available Annual Environmental and Reclamation Reports.
- You can find a link to the current report here: 2019 Environmental Report
- Polley Lake water met all BC Water Quality Guidelines for aquatic life parameters in 2019 with the exception of phosphorus, which was elevated even prior to mining. As Polley Lake is immediately adjacent to the mine site, this indicates the mine is doing a very good job of capturing and controlling run-off.
- A number of sites are monitored in Quesnel Lake, and in 2019 there were no exceedances of acute BC Water Quality Guidelines.
- At one monitoring site in Quesnel Lake, there was one minor copper exceedance of chronic BC Water Quality Guidelines in 2019, but as copper is also naturally occurring in the native soils and sediments around Quesnel Lake, and there are a number of creeks that empty into the lake near this sample site, it is difficult to know if this exceedance was natural or related to the mine.
We often get asked if we continue to discharge into Polley Lake or Quesnel Lake?
The mine discharges mine site water, that meets strict permit limits, through diffusers at depth into Quesnel Lake. This water is the only substance the mine is discharging to Quesnel Lake. The mine does not discharge water into Polley Lake.
- Mount Polley discharges only mine site water that meets strict Environmental Management Act (EMA) permit guidelines.
- treated by a water treatment plant, when needed to meet permit requirements, before being released into Quesnel Lake. The water going into the treatment plant (influent) is monitored on an ongoing basis, and the treated water leaving the plant (effluent) is sampled regularly for analysis. Not all water at Mount Polley requires treatment to meet EMA permit water quality guidelines before discharge, and in the past, water that was simply stored in Springer Pit was found suitable for passive discharge.
- The lake water quality is also routinely monitored and sampled regularly as part of the mine’s Comprehensive Environmental Monitoring Plan.
Continued monitoring data confirm that remediation efforts are effective.
- Currently, there are no indications in the monitoring data that the water discharged from Mount Polley is having any negative effects on Quesnel Lake water quality or aquatic life.
- If you are interested in looking at water quality data collected on surface water in the area around the Mount Polley mine, in addition to data in the mine’s annual reports, results are available through the BC Government Surface Water Monitoring Sites Interactive Map.