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MINING NEWS: Tulsequah Chief mine’s future is borderline Redfern Resources has installed treatment system for acid mine drainage; mine development plans on hold due to economic difficulties Sarah Hurst Mining News Editor
Environmentalists and indigenous groups have long been calling for a clean-up of the acid mine drainage at the former Tulsequah Chief zinc-copper-silver-gold mine in British Columbia, just across the border from Juneau. Vancouver-based Redfern Resources wants to do a full clean-up of the site, but only if it can reopen the mine. So mine critics find themselves in the dilemma of opposing the very process that could solve some of the environmental troubles.
The mine has been polluting the Taku and Tulsequah rivers with acid mine drainage since it closed in 1957. Redfern installed a passive treatment system in the mine’s lowest-elevation tunnel at the end of June, which is intended to remove up to 90 percent of the toxic metals leaching out of the mine. The company has spent just over C$500,000 on the system this year, according to Terry Chandler, Redfern’s president.
The treatment comprises a sulfate-reducing bacterial system and the use of locally obtained limestone as a sustained alkalinity system to raise the pH of the water, Chandler said. As there is no road access to the mine or infrastructure, such as power supply, it is not possible to use more sophisticated methods that would be more effective. Ideally Redfern would like to build a high-density lime treatment plant at the mine.
“The mine plan calls for a road, water treatment and progressive reclamation, to negate the problem completely,” Chandler told Mining News. “There is copper, lead and a little bit of silver. The zinc is problematic, because it requires a very high pH adjustment.” It will be six to eight months before the biological activity from the treatment system starts to impact on the zinc, he added.
The old Tulsequah Chief mine site is on the steep slope of a mountainside and most of the water in the Tulsequah River originates from the Tulsequah Glacier. Regular floods cause the river’s flow rate to double or triple and the water level at the mine site rises by six feet. “The river system goes through a complete reworking,” Chandler said. “In the areas that currently receive untreated discharge, there is some impact, noticeable metal contamination.” Concern over salmon Canadian and Alaska environmentalists in the Transboundary Watershed Alliance are concerned that developing the mine could harm the wild salmon in the watershed. The Taku River Tlingit First Nation launched a legal challenge to the mine and road proposal in 1997, but after succeeding in British Columbia courts, the Supreme Court of Canada ruled in November 2004 that the province’s officials had consulted adequately with the Tlingits about the potential impact on the fishery and their unresolved land claim. “In reality we have great support from the membership of the band, but the leadership has accepted recommendations from NGOs to oppose the project,” Chandler said.
As the Tulsequah Chief mine is so close to Alaska, the state’s Department of Natural Resources has been working on the project with the British Columbia government, according to Ed Fogels, head of Alaska DNR’s Large Mine Permitting team. “Commercial fishing groups in Southeast Alaska are very concerned,” Fogels told Mining News. “We want the mine to be developed consistent with U.S. and Alaska standards. The Canadians are keeping us involved and addressing our comments.” Full clean-up dependent on development Fogels agrees with Redfern that a full clean-up depends on developing the mine. “We think the Tulsequah mine can be responsibly developed,” he said. “The fish are doing great, the runs are increasing. It’s not that big of an environmental issue. The passive system will probably make it a lot better than it is now.”
The mine plan includes construction of a 100-mile access road from Atlin to the mine. “The biggest concern is that the road will bring a whole bunch more development to their territory that they won’t be in a position to control,” Chandler said. “But no one can do that without a significant amount of consultation with the First Nation.” Like Cash Minerals with its Division Mountain coal project in Yukon, Redfern is hoping to use Alaska’s Skagway Ore Terminal to ship concentrate to foreign markets.
The new mine would be built down below the river level, and would be sealed and flooded on closure, after an estimated eight to nine-year life. Power to the mine would be diesel-generated. Redfern argues that the mine will create high-paying jobs for local people near Atlin. But the Tulsequah Chief project faces economic difficulties. An updated feasibility study showed high construction and operating costs and a reduced mineral resource estimate, causing the company to put its plans on hold in May this year. “We need to get back in there and define some additional resources,” Chandler said. The project is also awaiting approval from the Canadian government.
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