Little Salmon/Carmacks First Nation is still concerned about a copper project proposed in its traditional territory.
On Friday, the Yukon Environmental and Socio-economic Assessment Board recommended the project be approved with conditions.
“They’re looking at it as a field-scale trial,” said Little Salmon/Carmacks Chief Eddie Skookum.
“Obviously they admit that there are no examples of a successfully detoxified sulphuric acid copper heap leach, but they recommended that it go ahead anyways.
“What’s the deal with that? It’s like going into a wild frontier and not knowing what to expect.”
Western Copper Corporation is proposing to build its open-pit mine 38 kilometres northwest of Carmacks.
The site is nine kilometres uphill from the Yukon River.
If the mine is not properly cleaned up when it is decommissioned it could leach acid and heavy metals into the important watershed.
Copper is especially dangerous to salmon; even small amounts can damage their sense of smell and make it impossible to migrate.
“A significant amount will remain in the heap after the mine’s closed and this copper might potentially find its way back into the river some time down the road,” said Skookum.
“A field-scale trial is basically a big experiment. Do we want to experiment with the Yukon River the way it is already?”
Skookum hopes both the mining corporation and the Yukon government will meet with the First Nation to talk through some of its concerns.
“The assessment of this project has been a major undertaking for our board,” said assessment board executive committee member Stephen Mills during a news conference on Monday.
“This is the first large open-pit mining project that’s been assessed through a public process of YESAA. In fact it’s the first mining project that we’ve assessed.”
Project screening began in February 2007.
During the process, numerous concerns were raised by both the Little Salmon/Carmacks First Nation and the Yukon Conservation Society concerning the detoxification of the site.
Western Copper will extract the copper with a quick and inexpensive method known as acid heap leaching.
As much as 13.3 million tonnes of crushed ore will be loaded onto a lined pad in 20-metre-high piles.
The crushed rock will then be doused with sulphuric acid to dissolve the copper, which will be collected from the bottom of the pad.
The company expects to mine more than14,000 tonnes of copper cathode each year for about eight years.
When mining is complete, the piles will be rinsed with water and a solution to neutralize the acid.
The assessment board hired an outside expert who determined the clean-up process would take twice as long as the company initially reported.
It would also cost around $21 million rather than Western Copper’s estimate $7 million.
However, some experts are saying it may never get cleaned up.
A study conducted by Lionel Catalan of Lakehead University in Thunder Bay, Ontario, identified potential problems with the process.
The tests were conducted using five massive vats, each containing approximately 4,000 tonnes of copper oxide ore.
Catalan found that when rinsing and neutralizing the heaps, channels form that allow solutions to run through more readily.
This means that pockets in the pile can remain acidic and filled with toxic heavy metals even after repeated rinsing.
These pockets can cause the entire pile to rebound and become dangerously acidic again after the site is closed.
To prevent this, the assessment board recommended that the first heap be treated as a field-scale trial.
The trial will be monitored and, if un-rinsed zones are found, the process will be adjusted to fix the problem.
“Rebounds happen within a few days or weeks,” said the assessment board’s project manager Michael Muller.
The board is sure that, if the company detoxifies the entire heap, there will be no surprises a few years down the line.
To ensure that the heap gets detoxified in the first place, the board is recommending that regulators collected security fees based on the expected cost of clean-up.
These fees will be reassessed each year, based on the test pile.
With a combination of good planning, thorough assessment, strong regulatory oversight and monitoring there is no reason why the mine can’t be environmentally safe, said Mills.
The assessment board has also recommended the mining camp be located on the site, rather than in the village of Carmacks, to attempt to prevent any social problems that may arise from such a huge influx of people into the community.
With two years of set-up construction, eight years of production and seven to 10 years of clean-up, Western Copper expects to have the mine completely cleaned up by 2028.
The recommendation has been sent to the two decision bodies: the Yukon government and Natural Resources Canada.
The government bodies have a period of up to 60 days to decide whether or not to accept the board’s recommendations.