The Yukon government says methylmercury has been found in a creek near the Eagle mine for the first time.
The neurotoxin is an extremely poisonous compound of mercury that has the potential to bioaccumulate in fish and animal tissues.
Yukon government biologists detected the toxin at four sites along Haggart Creek on October 18.
“Additional sampling for methylmercury will be undertaken to collect more information and better understand what this means for fish, wildlife and the environment,” a government spokesperson said in a statement Friday.
“Yukoners should continue to avoid eating fish harvested in the immediate area of the mine.”
Samples show cyanide and cobalt levels are also increasing in Haggart Creek.
While “elevated” levels of total mercury and other metals in Haggart Creek exceed water quality guidelines, the territorial government said those levels do not pose a heightened risk to people downstream of the mine.
In an update released Friday, the government said work is continuing to drill a series of wells behind the new safety berm. The hope is that those wells will allow workers at the site to intercept contaminated groundwater.
Work is also underway by receiver PriceWaterHouseCoopers to construct a new water treatment plant at the mine site.
Industry must do better, consultant says
The news came days before the biggest annual celebration of mining in the territory, which draws hundreds of investors and company representatives to Whitehorse each year.
Speaking at the first day of the Yukon Geoscience Forum on Sunday, Na-Cho Nyäk Dun environmental consultant Bill Slater painted a bleak picture of the situation.
The annual Yukon Geoscience Forum showroom in 2023. (Yukon Chamber of Mines)
“Winter is here, freshet is coming,” he told a crowd of mining executives and stakeholders. “We still don’t have groundwater collection systems in place and groundwater is contaminating Haggart Creek as we speak with concentrations continuing to increase every day.”
“The receiver fortunately has now built more than 300,000 cubic meters of storage. Most of that is now full. More than once we’ve been within one rainstorm of releasing large amounts of cyanide solution.”
In the update, the government acknowledged the urgency of the situation heading into winter. A spokesperson said the site team’s “primary focus” over the coming months will be preparing for spring melt and freshet.
Slater also rehashed the timeline leading up on the heap leach failure on June 24, and pointed out numerous instances where regulators failed to address risks at the site.
Treated effluent from Eagle mine discharging into nearby Haggart Creek. (Yukon Government)
“It has been a roller-coaster since the failure occurred, but not a regular roller-coaster,” he said. “It’s one where we realized as we left the station that the locks to hold the wheels on the tracks had not been installed.”
“We know that if we don’t all lean in the right direction at the right time, this roller-coaster will fly off the tracks. We have been perilously, perilously close to that situation many times, and we still face disaster every single day.”
Both Slater and Na-Cho Nyäk Dun (NND) Chief Dawna Hope said industry partners and government officials must do better going forward.
“You have to be prepared to call out and address the unacceptable risk profiles that are operating in your industry for there to be a future for mining in NND territory,” Slater said.