Although significant levels of copper and zinc were found downstream from the Tulsequah Chief mine, the mine’s drainage poses a low risk to fish in the Tulsequah River, according to a third-party water quality assessment released Dec. 20. The report also stated the discharge does not affect the Taku River. Scientists from Palmer Environmental Consulting Group, Core6 Environmental Ltd. and Triton Environmental Consultants, firms based in British Columbia, performed a study of the water quality at four sites in the Tulsequah River, where the mine is located near the confluence of the Taku River in British Columbia about 40 miles north of Juneau.
The mine was originally operated in the 1950s, and according to a past Empire report Canadian inspectors have known since 1990 that the mine is leaking sulfuric acid into the Tulsequah River, down the Taku River and into Southeast Alaska.
The Taku River flows into U.S. waters about 10 miles southeast of Juneau, and is the largest salmon-producing river system in Southeast Alaska, according to the Alaska Department of Natural Resources website.
Ministry mandate
The British Columbia Ministry of Environment’s Ian Sharpe sent a letter in August 2013 to Toronto-based Chieftain Metals Inc., the owner of the mine, requiring the company to “hire a qualified professional, with experience in aquatic impact assessment and in particular, fisheries impact assessment, to provide the Ministry with a risk assessment of the current mine effluent discharge (into) the Tulsequah River from the Tulsequah Chief mine site,” the letter stated.
In April 2012, the ministry required the company to treat acid waters coming from the excavation and removal of historical waste rock at the mine through the Environmental Management Act, according to the letter.
When the mine was shut down in June 2012, the water treatment plant ceased to operate, putting the company out of compliance with the EMA. In a past Empire report, the company said cost overruns precipitated the shutdown and the water treatment plant would not run until the company secured adequate funds. The treatment plant had operated since December 2011.
In July 2012, the Ministry of Environment required the mine to determine an interim water treatment strategy and test water quality regularly, according to the letter.
“Since then, the Ministry has been receiving regular water quality submissions, and communicating with Chieftain to review the status of the project and obtain updates on the action plan to come into compliance with the EMA authorization,” the letter stated.
Chieftain Metals was required to submit its third-party-conducted risk assessment to the ministry by Oct. 31, 2013. Continue reading….
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