An abandoned mine in far northwestern British Columbia on the traditional territory of the Taku River Tlingit First Nation (TRTFN) may be on its way to more concerted cleanup efforts as the receivership process for the bankrupt company that owned it ends.
In August, the B.C. government announced that the bankruptcy receivership process for Chieftain Metals, owner of the Tulsequah Chief Mine in the Taku River watershed south of Atlin, had come to an end.
The mine in question is an underground copper, lead and zinc mine that was operated by the Cominco Mining Corporation in the 1950s. According to the B.C. government, untreated mine effluent has been flowing nearly uninterrupted from the mine into the adjacent Tulsequah River, a tributary of the Taku River, for more than 60 years. A 2016 water quality study at the mine site found metal concentrations that could pose unacceptable risks to fish, fish eggs and other aquatic life in the area immediately adjacent to the mine discharges.
With the bankruptcy proceedings concluded, those who have worked on the reclamation at the mine took stock of what had been done and the plans for the future. The B.C. government and the TRTFN have been working on a conceptual reclamation and closure plan for the mine.
“The province is continuing to work closely with the Taku River Tlingit First Nation and is committed to engaging with stakeholders regarding a long-term approach to reclamation and closure that will include addressing acid rock drainage,” a B.C. government spokesperson wrote in an email to the News.
“The province is committed to holding all past and present owners of the Tulsequah Chief Mine accountable to address clean-up of the site.”
Early reclamation work at the site has been going on for the past three summers with the provincial government, TRTFN workers and outside consultants involved. The B.C. government representative summed up the work so far as projects involving site stability and access, ongoing water quality monitoring, and initiation of an aquatic effects monitoring program.
For TRTFN workers, the reclamation projects are a chance to do what can be done to right the wrongs of past mining regulation schemes and help the salmon that rely on the river for breeding.
TRTFN lands manager Roger Thorlakson said that while mining today is more responsibly regulated, when production started at Tulsequah Chief more than 60 years ago, environmental damage was the last thing on miners’ minds. He added that the B.C. government has been supportive of efforts to clean up the former mine site.
Jackie Caldwell, TRTFN’s mining officer said that reclamation work so far has included water sampling both by outside consultants and TRTFN itself.
Caldwell said that it is highly unlikely that the acid rock leeching can be stopped completely, but its effects could be diminished. Mitigation can include closing surface entrances and cracks that allow melting snow into the former mine shafts and adits, but closing the contaminated area completely is not possible. She added that testing work is important to fully understand the problem as is light detection and ranging mapping conducted last year that gave a better picture of waste piles left behind by the mine and other important geographical information.
She said having indefinite water treatment at the site is not a possibility that makes the First Nation comfortable. Long-term treatment would require workers to live on site and access to the remote area where the mine is located is very challenging in the winter.
Caldwell added that there has also been work on roads, bridges and a camp at the mine site that will be required. Most of this work was awarded to a local economic partnership.
Mark Connor, fisheries coordinator for TRTFN, said the acid mine drainage has negative impacts on the fish that use the stream but plans are in place to improve the area as salmon habitat.
In some areas, acute toxicity sufficient to kill aquatic life outright has been observed near the “dead zone” where the mine adits spill out into the river but the long-term effects are harder to know.
Connor said previous work done by a mining company planning to reopen the mine led to a letter of credit being held by the federal Department of Fisheries and Oceans to cover cleanup work. He said nothing has been approved yet but work to connect a former gravel pit that is filled with groundwater to the rest of the salmon-bearing stream creating a sheltered spawning area is being considered.
Contact Jim Elliot at jim.elliot@yukon-news.com
