A regional conservation group recently called attention to the prospective sale of a disused Canadian mine, and suggests the exchange could bode poorly for efforts to maintain water quality in transboundary rivers.
The Tulsequah Chief zinc mine is across the Canadian border in British Columbia located along the Tulsequah River, a tributary of the Taku River. It has been out of use since 1957, and its critics contend it has since been a source of headache both for its past owners and for subsistence users along the Taku watershed it neighbors.
Constructed and initially operated for five years during the 1950s, after a lengthy lull it was purchased by Redfern Resources Ltd., which applied for an environmental assessment (EA) certificate to develop a 2,480-ton-per-day underground copper, lead, zinc, gold and silver mine at the site. Twice since, the mine has changed hands due to bankruptcy, the latest occurring last fall when owner Chieftain Metals Corporation was placed into receivership. Since its initial abandonment in 1957, acid has been draining from the mine site into the Tulsequah River, which in turn is a tributary to the Taku River.
According to B.C.’s Ministry of Energy and Mines (MEM), acid mine drainage is the outflow of acidic water from metal or coal mines. While the acid in rock is formed through a naturally occurring process, fine particles created and left exposed through the blasting or crushing processes involved in ore extraction speeds up the oxidation process. When oxidation occurs acid is rapidly produced, and can go on for many years.
At this particular mine site, the Tulsequah River is the primary receiving environment of its acidic effluent. The costs for the pollution abatement necessary to safely reopen the Tulsequah Chief mine have proven an unsurpassable obstacle for both mine owners. A treatment center was installed by Redfern in 2005 but never used, with the company arguing it needed the mine open to finance its operation. The facility was subsequently sold along with other mining equipment to satisfy creditors. After Chieftain Metals acquired the site in 2010, another acid-water treatment plan was developed and put into action for a short period in 2012.
The mine went into another receivership after its owner, Chieftan Metals Corporation, was pressed into bankruptcy late last year. The provincial government implemented a Tulsequah Chief working group in September 2016 to bring together all provincial regulating agencies to ensure communication and coordination of action.
Shortly after Chieftain Metals was placed under receivership, on September 26 inspectors from two ministries and the Taku River Tlingit inspected the Tulsequah Chief mine site. Inspectors found a number of non-compliance issues at the site including no caretaker on site, drainage issues at the sediment pond, and unsecured chemicals at the site. MEM has since reported hiring a contractor to “store and properly secure all chemicals identified on site,” with most of the work completed in December 2016.
Water quality watchdog Rivers Without Borders reports that the seeping of rock-produced acid into the neighboring watershed still remains a problem at the site, posing a potential risk to salmon and other fish inhabiting the system. Despite a statement of cooperation signed between British Columbia and the state of Alaska last October promising more dialogue between the two on mining concerns, news of a prospective buyer to the site has caused the group concerns. The cordial agreement had been reached following heightened concerns about protecting river water quality, following the rupture of a tailings dam at Mount Polley into the Fraser River system in August 2014.
Rivers Without Borders announced the possible purchase of Tulsequah Chief on June 29, noting it had learned of the arrangement from a redacted post on receiver Grant Thornton’s website, rather than from the provincial government. What is disconcerting to the organization about the proposed sale is the lack of dialogue between British Columbia’s provincial government and Alaska.
“B.C. did not say one word about this potential buyer,” commented Chris Zimmer, Rivers Without Borders’ Alaska director.
One of several concerns the group voiced in last month’s media release was the province’s strategy of relying on mine operators to implement full cleanup of the site is not working, in part because the financial incentives are not there – in the short term for a smaller scale mine like Tulsequah Chief, but in the longer term for much larger ventures being developed across the province.
“Trying to re-open the Tulsequah Chief a third time is not a cleanup plan. It is a recipe for another bankruptcy, more pollution, and opening up the heart of the Taku to mining and road building,” Zimmer commented in the release.
“The Tulsequah Chief is not a viable mine, and it’s time to clean it up and close it down once and for all,” it quoted John Morris, Sr., an elder and Tribal Council member of the Douglas Indian Association. “Two mining companies have gone bankrupt trying to re-open this mine and have left a legacy of toxic acid mine drainage into salmon habitat. B.C.’s assurances of mine cleanup seem hollow, with B.C. more interested in re-opening this failed mine rather than cleaning up its 60 year legacy of pollution.”
A body metals study on Taku River king salmon and Dolly Varden char concluded by the Alaska Department of Fish and Game in October 2016 showed no significant difference in metal concentration in fish captured near the mine site, when compared to fish captured upstream and downstream of it. However, the mine’s authors noted the scope of the study was limited to whether fish were impacted, not whether Tulsequah Chief was polluting nearby waters.
An aquatic ecological risk assessment undertaken by Chieftain Metals in 2014 likewise found there had been “no unacceptable risk” to river salmon from the mine, but concerns about the assessment prompted the province to require another one to be taken, which was not completed by the time the company went into receivership.
The ongoing issue highlights similar concerns about mining projects elsewhere in the province. The Red Chris Mine, which began operations near the Stikine River’s tributary Iskut in 2015, is one such case. Zimmer noted the sizable copper and gold mine makes use of watered tailings storage similar in design but larger in scale than that at Mount Polley. In the official autopsy examining the latter’s rupture, one of the key recommendations to prevent similar incidents was to use dry tailings storage techniques.
Involving stacking relatively dried cake leftover from mining operations, this method would virtually eliminate ground water contamination and runoff, and would be resistant to seismic disturbances. If used as intended, risks of catastrophic ruptures such as that at Mount Polley would not be a concern. However, the main reason to favor watered tailings over dry storage is financial, being less costly to develop and maintain slurried tailings. Other logistical considerations are to be considered, such as rainfall and onsite water storage.
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