In December of 2022 the B.C. government approved a permit amendment to allow the continued discharge of wastewater into Quesnel Lake by Mt. Polley Mine until 2025.
A permit, in place since April of 2017, has allowed Mount Polley Mining Corporation (MPMC) to discharge mine effluent into Quesnel Lake near the outlet of the lake to the Quesnel River.
The water is rainfall accumulated on the mine site, some of which comes into contact with mining operations and becomes contaminated.
Prior to the tailings dam breach in August of 2014, this water was stored in the tailings storage facility held by the failed dam or in open pits.
The permit allows for the discharge to continue for another three years within specific parameters, with measurements taken by MPMC monitors from the initial dilution zone.
The permit allows for up to 50 per cent mortality in 100 per cent effluent of Rainbow Trout fry at the outlet itself and also includes requirements for the pH, total suspended solids and many specific elements and metals, including copper.
The mine currently uses a Veolia ACTIFLO treatment system to treat the water, which helps to reduce dissolved solids and Don Parsons, chief compliance officer for the mine defended the mine’s record in complying with the permit and said there is a response plan in place in cases where toxicity or metal levels are too high which allows the water plant to recycle the water through the treatment until it meets standards.
He also said MPMC is in the process of applying to extend the permit for the life of the mine, which is forecast to be another 10 years.
The mine also has a major mine expansion application in front of the province, according to Parsons. The Ministry of Environment confirmed the mine can apply for a permit amendment at any time.
The ministry said the amended permit took into account research published in Sept. 2022 and the amended permit “imposes discharge, monitoring and reporting requirements that ensures the ongoing protection of the environment.”
The mine’s current water treatment and monitoring does not satisfy the Concerned Citizens of Quesnel Lake (CCQL), a group advocating for stricter oversight and more treatment of the mine effluent.
“I don’t consider it treated,” said Christine McLean of CCQL, noting residents would not be allowed to empty dishwater into the lake, yet the mine can discharge contaminated water from the site. The group was frustrated the permit amendment was approved.
She said the group wants to see more independent monitoring of the discharge and more strict permit parameters, noting a previous plan for water discharge prior to the tailings breach included reverse-osmosis water treatment to more thoroughly clean the water of dissolved metals and other additives.
This, however, is not the option MPMC favours after looking at “best available technologies”, said Parsons, noting a reverse osmosis system would create a lot of brine from the removed contaminants, which would then need to be disposed of or stored, creating another problem.
But McLean asserts “dilution is not a solution to pollution.”
Researchers at the Quesnel River Research Centre (QRRC) said their monitoring of the effluent in the lake is not yet complete, but their work could create a clearer picture of how the effluent plume moves once it enters the lake.
They are currently doing constant monitoring of parameters not currently covered by the permit, including specific conductivity as well as temperature and have been doing monitoring for a couple of years.
Most mine discharge permits apply to effluent released into rivers, which is how the permit and sampling protocols may have been developed, said Dr. Ellen Petticrew, a research chair at UNBC who is associated with the QRRC. However, in a lake, the effluent will move differently than it would in a river.
During much of the year, a lake stratifies into layers, which do not mix until spring and fall “turnovers.” It is unclear if this might have an impact on how effective the current permit sampling by MPMC is to ensure the effluent is diluting down to safe concentrations.
She said the research QRRC is doing includes parameters not required to be monitored by the permit, so it could shed more light on possible impacts or lack of impacts from the discharge, especially on biologically important factors for organisms living in the lake and what impacts there could be over the longer term.
Petticrew recognized the challenges of balancing costs and benefits of any increased sampling, noting better models could help create more effective monitoring in the future.
“We are disappointed that they went ahead with this permit before the results are all in,” said Petticrew, noting their current funding wraps up in March 2023 and the data could then be compiled and reported out.
A statement from the Ministry of Environment said: “The plan is due for review in 2023 and the ministry expects the revised plan will incorporate new science and findings from ongoing work, including the work done by UNBC on remobilization of lake sediment and tailings from the dam breach,” referring to a previous study by QRRC. The ministry did not provide any examples of other effluent discharges into lakes but said:
“The comprehensive environmental monitoring program for Mount Polley Mine is designed to consider all the current knowledge and unique aspects of the local environment.”
Kukpi7 (Chief) Willie Sellars, of the Williams Lake First Nation (WLFN), said WLFN has been working collaboratively throughout the permit extension process to have any of their concerns addressed.
“If the science checks out then it’s something we can get behind,” said Sellars about the permit extension, which WLFN did not have an issue with.
“It’s tough, finding the balance between industry and environmental stewardship in a resource-based economy.”
WLFN’s natural resource department said they have developed an environmental management plan which deals with many aspects of the mine, “including trigger response plans, environmental reviews, monthly environmental meetings with MPMC and scheduled meetings with the various ministries during the operational as well as the ‘care and maintenance’ down time.”
WLFN has a participation agreement with Imperial Metals, which owns MPMC meaning they do receive economic benefits from the company.
Information provided by the Ministry of Environment detailed the environmental monitoring and compliance of Mt. Polley Mine from 2017 to 2020. Over the three-year period, there were some incidents of non-compliance on the part of the mine.
While most of those were administrative in nature, the ministry did report one incident in May 2018 when effluent discharge exceeded the permit limits for total copper, dissolved cadmium and total aluminum.
This resulted in discharge being temporarily suspended for 19 days. One incidence of a monetary penalty occurred as well, with the mine fined $9,000 for failing to submit some required information and/or documentation.
MPMC submits monthly, quarterly and annual reports on their environmental monitoring program and all documents must be signed off by qualified professionals, said the ministry.