Yukon Water Board allows temporary release of more contaminated water from Victoria Gold mine

The Yukon Water Board has approved an emergency licence amendment for Victoria Gold's Eagle Gold mine that will temporarily allow water with higher concentrations of contaminants to be released into the environment.

The amendment, effective Dec. 20 until March 15, 2025 comes with a number of conditions, including requirements that water discharges stop if contaminants in nearby Haggart Creek reach levels harmful to fish. 

The discharged water will be "not acutely toxic" but may contain up to double the concentration of total copper and suspended solids compared to before, as well as more weak acid dissociable cyanide and dissolved iron. 

Firm PriceWaterhouseCoopers (PwC), which took charge of the Eagle Gold site in August after Victoria Gold went into receivership, applied for the emergency amendment last month. It cited the rising volume of contaminated water on-site, the inability to properly treat it for cyanide and diminishing storage capacity as key reasons for its application, warning of an "uncontrolled" release should facilities be overwhelmed.

"The Board finds the uncontrolled release of cyanide-contaminated water to the environment presents a risk of adverse environmental impacts to the receiving environment and requires immediate preventative action," the board wrote in its reasons for approving the application.

It added that the board requires "operational changes" to prevent "adverse environmental and social impacts." 

Managing contaminated water at Eagle Gold has been a major issue since late June, when an estimated four million tonnes of ore slid off the mine's heap leach facility. Approximately half of that material, which was being treated with cyanide solution, left containment and spilled into the surrounding area, raising concerns about the impact on both surface and groundwater. 

The on-site water treatment plant was not designed to treat cyanide. While PwC has been upgrading the plant to do so, that work had not been completed yet as of the filing of its emergency amendment application. 

Under the amendment, PwC may discharge water containing a maximum of 0.05 mg/L of weak acid dissociable cyanide, 0.6 mg/L of copper and 30 mg/L of suspended solids. 

PwC may also discharge water with up to 6.4 mg/L of dissolved iron — the same concentration for total iron under the existing water licence conditions, meaning that the total amount of iron in the water will be much higher. 

Iron, the board's decision noted, is required for cyanide destruction. 

The amendment comes with several "adaptive management" measures. For example, the concentration of weak acid dissociable cyanide in discharged water must be lowered back down to 0.03 mg/L should the concentration detected at a downstream monitoring station on Haggart Creek exceed 0.005 mg/L. As well, dissolved copper in discharged water may have a maximum concentration of 0.2 mg/L unless that's found to have an adverse impact on aquatic life, at which point it must be dropped down to 0.1mg/L

PwC is subject to several requirements throughout the emergency amendment period, including conducting daily and weekly sampling and testing of both discharged water and points along Haggart Creek. It must also submit a supplemental water management plan by Dec. 31, a progress report by Jan. 15, 2025 and reports on topics including the volume of water it discharges, the quality of the water discharged and available storage capacity on site. The reports and sampling and testing results must be provided to both the water board and the First Nation of Na-Cho Nyäk Dun, on whose traditional territory the Eagle Gold mine and surrounding area are located. 

While PwC had initially requested that the emergency period last until the end of March, the board, acting on comments provided by the First Nation of Na-Cho Nyäk Dun, reduced the time by 16 days. Citizens of the First Nation, the board noted in its decision, have relied heavily on Arctic greyling as a foodsource in the wake of declining salmon numbers. The greyling stage at Haggart Creek and the South McQuesten River Fishing in late March, and "restoring robust" water standards before that was "imperative" to protect the fish.