Casino Mining Corporation says it will submit a new proposal for its massive copper and gold mine to the Yukon Environmental and Socio-economic Assessment Board by Dec. 31, 2017.
YESAB can then strike a panel to review the project, which could produce an estimated 8.9 million ounces of gold and 4.5 billion pounds of copper over a 22-year mine life.
The company says the new proposal will include an updated tailings pond design that will require less water to reduce the impact of a possible dam failure. The site’s airstrip will also be moved, to reduce the project’s overall footprint.
Casino submitted its original proposal to YESAB in January 2014, but in February 2016, the board bumped the project up to a panel review, the territory’s highest level of assessment.
The decision was made over concerns about the tailings pond and potential impacts to the Klaza caribou herd, whose range includes most of the project’s footprint.
As part of the panel review process, YESAB sent Casino a 95-page list of information required for its new proposal in June. Last week, Casino president and CEO Paul West-Sells told YESAB that the company plans to complete its submission by the end of 2017.
West-Sells told the News that much of that time will be used to complete new engineering work for the redesigned tailings pond.
He said the new design will “end up with a lot less water,” because only the tailings that could leach acidic water into the environment will be covered with water. The more benign material will be placed outside the pond.
The potentially acid-generating material will also be moved further back from the crest of the dam, West-Sells said, so that if there were a failure, those tailings would be less likely to wash downstream.
“There will just be a much larger beach,” he said, referring to the inside slope of the dam that rises above the water level.
But West-Sells couldn’t say whether the height of the dam will decrease as a result of the changes. At 286 metres, the proposed dam would be the highest in the world.
Lewis Rifkind of the Yukon Conservation Society said it’s good that Casino is going to take its time with the submission, as “there is a lot of work that has to be done.”
He said it might be possible for Casino to avoid a tailings pond altogether by stacking the acid-generating tailings and covering them with an impermeable cover, but he acknowledged that the cost might be prohibitive.
“It can get very expensive very quickly,” he said. “We have to recognize that money does run out.”
But he also pointed out that the Casino deposit is located up in the mountains, meaning that “if something goes, it’s going to flow a long way.”
Casino is also planning to relocate its proposed airstrip to a spot adjacent to the main access road. The original location was about 10 kilometres from the site, but would have required its own access.
West-Sells said this change will help shrink the project’s overall footprint, which could reduce the impact on the Klaza caribou herd. “It keeps some unimpacted area unimpacted.”
He said there are no plans to modify the design of the access road, which includes upgrades to the 83-kilometre-long Freegold Road out of Carmacks and construction of an additional 120 kilometres of all-weather gravel road.
But Rifkind said that access road poses a serious threat on its own.
“The access road is going to be a huge engineering feat, and that’s going to be very environmentally destructive,” he said.
He’s concerned that the new road will open up the whole region to more hunting and exploration, which could put a strain on the Klaza caribou.
Casino also plans to conduct more traditional land use studies with affected First Nations within the next year. West-Sells said some of that work has already been done, but “as a result of further discussions with the First Nations, there was a desire to do that in greater depth.”
The affected First Nations include Selkirk, in whose traditional territory the mine site is located, Little Salmon/Carmacks and Tr’ondek Hwech’in, whose traditional territories encompass parts of the access roads, and Kluane and White River, which are downstream of the tailings dam.
Once Casino’s proposal is submitted, YESAB’s executive committee will review it to make sure it’s complete. After that, a panel will be struck to begin the review. According to YESAB’s rules, the panel review will include public hearings in various communities.
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