The territorial government missed its chance to propose changes to the Carmacks Copper project, and that worries conservationists.
The mine, if built as planned, may leak toxic metals into salmon spawning grounds, according to the Yukon Conservation Society.
The Yukon government had until September 2 to send a screening report to the Yukon Environmental and Socio-economic Assessment Board.
The government has until September 17 to either accept or reject the project.
With no screening report submitted, de facto government approval of the mine has been made, said Karen Baltgailis, the society’s executive director.
It is unlikely the government would reject the mine outright, said Baltgailis.
If it had problems, it would have demanded changes in its screening report, she added.
If the proposed open-pit mine moves forward, millions of tons of crushed ore would be piled high, then doused with sulfuric acid to separate the copper.
The acid would later be washed off with a neutralizing solution and water.
But this method has not been properly tested, and may leave traces of acid, copper and heavy metals, said Baltgailis.
This toxic run-off would flow into Williams Creek, which enters the Yukon River upstream of a chinook and chum salmon spawning area.
A small field trial should be attempted before the mine receives full approval, said Baltgailis.
The society also worries not enough security money will be put down by Western Copper Corp. for clean-up.
The company’s highest estimate is $22.9 million; the conservation society says it may cost double that amount.
“So, it will be not only subsistence fishers and salmon that pay,” said Baltgailis. “Yukon taxpayers will also be on the hook.”