Water Quality

Buckhorn Mine Monitoring

The Buckhorn Mine operated from 2008-2017. Shortly after the underground mine on Buckhorn got the go-ahead and mining operations began in 2008, water quality monitoring data began to show increasing pollutant levels at the Buckhorn Mine. The issues began when the mine used contaminated development rock to construct the mine facilities, instead of putting it on liners as required. Several other factors have contributed to the degradation of water quality at the site including: discharges from the underground mine, the mine surface, and from the treatment facility (which early on, used inadequate technology).

The regulator, Washington State’s Department of Ecology (Ecology), issued the first penalty for a water quality violation to the Buckhorn Mine’s operator, Crown Resources (a wholly owned subsidiary of Kinross Gold Corporation) in April 2009, along with numerous corrective action requirements. Ecology issued the next penalty was issued in November 2010 for purposefully causing compliance water quality samples to be unrepresentative of the more polluted mine water. Unfortunately water quality problems persisted and got worse, leading Ecology to issue the largest penalty in Washington State history ($395,000) in July 2012; the 2012 penalty was appealed by Crown and subsequently settled with Ecology. Staff changes at Ecology compounded the challenges for the agency in addressing the pollution issues because of the time it takes for new personnel to become oriented.

In Washington State, the Department of Ecology (Ecology) is designated as the water pollution control agency for purposes of the federal Clean Water Act. This means they are responsible for issuing and administrating discharge permits under the Clean Water Act. The mine received its initial Clean Water Act discharge permit in 2007. The permit was revised and reissued in 2014, and immediately upon reissue, Crown appealed the renewed permit. Crown’s appeal was rejected by the Pollution Control Hearings Board, Ferry County Superior Court, and the Washington State Court of Appeals. The Appeals Court ruling affirmed that the water surrounding the Buckhorn Mine must be left almost as clean as it was before the mine was developed. The permit upheld by the court clarified the farthest extent from the mine that contaminants are allowed to spread and affirms that the water quality criteria (beyond this farthest extent) is set at the background level as it was before the mine was constructed.

Violations of the mine’s 2014 Clean Water Act discharge permit formed the basis for OHA’s Clean Water Act citizen suit, which was filed in 2020 and settled in 2024. During the legal process, Crown stipulated (or agreed) to having 3,538 monthly permit violations of numeric effluent limits between 2015 and 2022. This translates to 107,668 daily violations of the Clean Water Act.

Nearly all locations with water quality poor enough to exceed permit limits in the past continue to violate the permit – even with the mitigation measures put in place by Crown. The degradation of water quality outside the capture zone shows that the mining companies are not containing all mine-influenced water. OHA’s 2024 settlement with the mining companies includes provisions to investigate and capture additional mine-influenced water.

Water Quality Contamination

The red dashed line in the above graph shows the allowable (2014 permit) level of sulfate. The other dashed lines show the general trend of sulfate levels in various monitoring locations.

These monitoring wells are located in a fault downgradient from the mine, just outside the capture zone, which is supposed to capture all mine contaminants. Sulfate concentrations in all these monitoring wells (MW) are still increasing. Many values in MW-14 and MW-2R even exceeded the State groundwater standard (250 mg/L — a much higher level than the 69.5 mg/L allowed by the permit). Although MW-14, which is closest to Gold Bowl Creek, had the highest peak concentrations, the recent overall trend in that well could be decreasing slightly.

Water Quality Not Improving at The Buckhorn Mine

MINE SEEPAGE EXCEEDS PERMIT LIMITS; VIOLATIONS MOUNT

Mine Seepage Exceeds Permit Limits; Violations Mount The 2018 Annual Coordination Meeting at the Buckhorn Mine included a presentation from Dr. Ann Maest, OHA’s consulting aqueous geochemist. Dr. Maest has worked on Buckhorn issues for 25 years and is an expert on the environmental impacts of mining, working on projects internationally. In contrast to the water quality presentation given by Crown Resources, Dr. Maest took a critical look at the previous year’s data. In her presentation, Dr. Maest concluded that, despite ongoing mitigation measures at the mine, water quality was not improving in key locations at the site. The presentation focused on the water quality impacts of two contaminants of concern: sulfate and nitrate. Read More…