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Casino's massive mine proposal sent to highest level of assessment

Yukon's largest proposed mine has been bumped up to the highest level of environmental assessment in the territory, over concerns about its tailings pond and possible impacts on caribou.

Yukon’s largest proposed mine has been bumped up to the highest level of environmental assessment in the territory, over concerns about its tailings pond and possible impacts on caribou.

The Yukon Environmental and Socio-economic Assessment Board announced on Thursday that the Casino mining project requires a panel review, which will include public hearings in various communities.

This will be the first panel review that YESAB has undertaken.

Ken McKinnon, YESAB’s spokesperson for the executive committee reviewing the Casino Mining Corporation’s proposal, said the decision was made because the project “involves technology that is controversial in Yukon” and because it might have significant adverse environmental or socio-economic effects.

According to the Yukon Environmental and Socio-economic Assessment Act, each of those factors is enough to require a panel review.

The Casino project is a copper, gold, molybdenum and silver deposit located 300 kilometres northwest of Whitehorse. It would be accessed along a 120-kilometre extension of the Freegold Road, which runs northwest out of Carmacks. The project is designed to process 120,000 tonnes of ore per day over a 22-year mine life.

The major issue at play here is Casino’s proposed tailings dam, which would be the highest tailings dam in the world. At 286 metres, it would stand just slightly shorter than the Eiffel Tower. It would be 2.5 kilometres wide, and would retain a tailings pond expected to cover 11 square kilometres. The pond would hold 950 million tonnes of tailings and 650 million tonnes of waste rock.

“From a stability perspective, a facility or a dam that’s retaining water as well as tailings has a high risk with regards to possible physical failure,” said Nathan Aasman, a lead assessor on the project. “So this requires long-term inspections and monitoring and maintenance.”

Aasman explained that tailings dam technology has come under scrutiny since the failure of B.C.‘s Mount Polley dam in 2014. He said there’s growing debate among experts about how to safely store mine tailings “in perpetuity.”

McKinnon pointed out that while most of the material released during the dam failure at Mount Polley was benign, some of the mine waste at Casino would be potentially acid-generating, which could have much more serious environmental impacts.

He said a dam failure at Casino could release tailings into the Donjek, White and Yukon rivers.

YESAB is also concerned about possible impacts on the Klaza caribou herd, whose range includes most of the project’s footprint. Aasman said the project could reduce caribou habitat and could fragment some parts of their range.

Since the Casino Mining Corporation first submitted its proposal in January 2014, it hasn’t provided enough information to address those concerns, McKinnon said. The company has responded to two information requests from YESAB, in March and December 2015, but both responses have been met with questions and criticism from First Nations and the territorial and federal governments.

“There isn’t one of those contributors (that) didn’t say that they need further information,” McKinnon said.

Now that the proposal is going to a panel review, YESAB has three months to put together a panel of three board members. The executive committee will also work on guidelines that outline the information Casino must submit to the panel.

The panel will also organize public hearings, which are one of the most important elements of the review process. McKinnon said he wouldn’t be surprised if every community in the Yukon ended up wanting its own hearing.

Mara Pollock, YESAB’s legal counsel, said the panel also has “quasi-judicial authorities,” meaning it can subpoena witnesses, call evidence and make orders.

YESAB will have 15 months to complete the review, not including the time it takes Casino to provide the information it’s asked for. That fixed timeline was set out in Bill S-6, which made controversial changes to Yukon’s assessment act when it was passed last year.

McKinnon said the timeline will be “really tight,” but added that YESAB has met its deadlines in the past. He also said that Casino has been very cooperative in the assessment process so far.

Once the review is complete, YESAB will recommend that the project be approved, with or without conditions, or rejected.

McKinnon said he expects the review will cost $1 to $2 million, though he said that will depend partly on the number of communities that want public hearings. He said YESAB has spent $500,000 on consultants for the Casino project so far.

Paul West-Sells, president of Western Copper and Gold, the company that owns the Casino project, said there are “pluses and minuses” to YESAB’s decision.

“It was certainly a little bit surprising if you look at the last round of questioning,” he said, pointing out that none of the agencies providing comments were asking for a review at that point. He said the company was preparing for a third information request, rather than a full panel review.

But he’s also glad the decision was made now, rather than later in the process, when a panel review might have meant a significant delay.

As for the public hearings, he said the company will “encourage any additional public interaction on this project.” He said the company has already hosted public meetings in Whitehorse, Carmacks, Pelly Crossing and Dawson, before and after the proposal was submitted.

Still, he said he believes the single, large tailings pond is the best option for the project. “If you look at the potentially acid-generating material that we have, the best available technology for storing that material is under water cover.”

West-Sells said the company has spent $90 million on the Casino project so far, and he feels confident the company will get the financing it needs to complete the assessment.

“It’s an important project. It’s important that it’s done right and we’re committed to that,” he said. “And if it takes a little longer because of this panel review, then that’s fine.”

Lewis Rifkind, with the Yukon Conservation Society, said he didn’t foresee YESAB’s decision either. But he said it shows the assessment board is “taking the time to do it right.”

Rifkind said mining companies should be moving away from wet tailings altogether and should look more seriously at dry stacked tailings instead. And as for this project, he said, the size is a major concern.

“I think it’s too big. They’re trying to do too much with technology that’s very dubious. That tailings dam is a show-stopper. And I don’t think it can be built safely or built in such a manner as to last forever.”

Contact Maura Forrest at