It’s been a tough week for Western Copper Corporation.
The Yukon Water Board has held hearings in Whitehorse throughout the week on the Vancouver-based mining junior’s plans to build a mine just outside Carmacks, and the meetings have attracted no shortage of criticism.
First Nations and conservationists worry the mine is poorly designed and could end up dumping dangerous chemicals into the surrounding watershed, which flows into the Yukon River.
A number of revelations at the meeting appear to substantiate these concerns.
First, the company admitted its proposed design has never been used in a commercial copper mine.
Rather than build a costly mill, the company wants to douse massive piles of ore with sulphuric acid to separate copper from rock, then cleanse the pile with an alkaline solution. This design is called an acid heap leach.
Western Copper points to a successfully reclaimed mine of this design in Arizona, called Equatorial Tonapah, as proof that their plans are sturdy. But the Arizona project never rinsed its waste rock. Instead they simply buried the ore.
Jonathan Clegg, vice-president of engineering for Western Copper, said in an interview this only goes to show that Western Copper plans to take one further precaution than anyone else.
He noted that other types of heap leaches, such as Yukon’s Brewery Creek mine, which used cyanide to separate gold from ore, have been successful in the territory.
And small-scale tests of Western Copper’s plans have worked as promised, said Clegg. “It hasn’t been applied to another heap on a commercial basis – not that it hasn’t been tested.”
But this hasn’t alleviated critics’ concerns that the Yukon will be used as a guinea pig for an untested design.
Then came another bombshell; when the Little Salmon/Carmacks First Nation unearthed a document more than 20 years old that describes big problems encountered by Western Copper during early winter tests at the Carmacks site.
Chemical spills and heavy snows presented problems, according to the 1994 federal report.
But the big issue raised by the report is how the company was unable to properly clean up its acid-soaked ore. Fine, sandy material prevented the alkaline solution from fully rinsing the pile.
Again, Clegg downplayed the report’s significance in an interview. The purpose of the test was to see whether leaching would work in Yukon’s bitter winters. It does, he said.
“The company never planned to rinse and neutralize the test,” said Clegg. “That’s not correct information and it’s not substantiated anywhere.”
Clegg also took a walloping from the board’s own technical expert, Cord Hamilton, who clearly remained skeptical the mine’s design would work as promised. Many of his questions for Clegg through Thursday morning were either answered with grudging agreement or a promise to deliver more information later.
On Thursday afternoon, board members heard impassioned pleas from members of the Little Salmon/Carmacks First Nation, who called for tough measures to protect the environment.
“Our life, culture and tradition are at stake,” said Chief Eddie Skookum. “What will happen in the event of an environmental mishap?”
Salmon are particularly sensitive to the presence of copper in water. It harms the fish’s sense of smell, which in turn hampers salmon’s ability to navigate.
“If anything goes wrong, I wonder how I’ll tell my grandchildren,” said Michael Vance, lands director for the First Nation.
Contact John Thompson at