Casino Mining defends heap leach plan as distrust of gold extraction method lingers

The heap leach facility at the Casino mine will be different from the one that failed last summer at the Eagle gold mine in the Yukon, according to the mining company.

The Casino mine — which is still in the environmental assessment phase — is 300 kilometres northwest of Whitehorse via Carmacks, on what the company says is one of the largest copper-gold deposits in Canada. Shena Shaw, Casino Mining's vice-president of environmental and community affairs, gave a presentation at the Association of Yukon Communities' annual general meeting on April 25. 

Whitehorse Mayor Kirk Cameron addressed the "poor reputation" of heap leaching during the question-and-answer portion. He asked Shaw to explain why Casino's technology is more trustworthy than Victoria Gold's.

"It's obviously a completely fair question," Shaw replied, and said they are still waiting for the investigation results to learn what went wrong at Eagle. "I don't want to go out too far to say what they did wrong, but there are some significant differences," she said.

Shaw said the Casino mine will use different ore and a different liner system from the Eagle mine, and strip the soil down to bedrock under the facility for stability. 

"I know it's hard to believe right now … but [heap leach facilities] do operate all around the world and in cold climates without problem in other places," Shaw said.

Heap leaching refers to the method of separating gold from surrounding solids.

Casino is a much larger mine than Eagle, Shaw continued. It will have an 882-bed camp with 600 to 700 permanent employees and 100 to 200 contract staff. It'll have its own power plant, landfill and water treatment system. Its projected lifespan is 27 years.

"The scale of what we're producing is not even comparable to Victoria Gold," Shaw said.

Public distrust of heap leach lingering

There have been a few calls to ban heap leach mining in the Yukon since the Eagle mine failed. 

The First Nation of Na-Cho Nyäk Dun has called for a ban on its traditional territory, alongside five other calls to action. 

A local advocacy group, Yukoners Concerned, circulated a petition calling for a ban on open pad heap leach mining, which was submitted to the Legislative Assembly with 237 signatures on April 24. The Yukon government said it was not going to license another heap leach facility until the review is finished and the outcomes are "incorporated, as appropriate."

Cameron told CBC News he's also heard from residents who are concerned about another heap leach facility in the territory as a "gut reaction" right now.

"It is highly toxic. It's terrible for our environment, especially for waterways, and of course, Casino is not all that far away from the Yukon River," Cameron said, adding that he ultimately trusts the assessment process.

"I'm personally not all that uncomfortable — but I've certainly heard a lot of people out there who've expressed concern that we're potentially into high risk if indeed that is not properly designed."

Shaw said the mine is still five to seven years away from completing the permitting process.