A Toronto environmental company is cleaning up a toxic Manitoba mine site at no cost to taxpayers. Its compensation? It gets to keep any gold it can extract from a stockpile of arsenopyrite concentrate.
“As the price of gold and copper began to rise, we realized the possibility for extracting value from mine tailings,” says Ross Orr, president and CEO of BacTech Environmental Corporation.
The company is employing bioleaching technology, which uses microbes to extract valuable metals from undesirable materials.
“Bacteria digest the sulphides to break up the matrix of the tailings materials,” says Orr. “The arsenic and iron go into the solution and the precious metals go into a precipitate for which we can use conventional extraction methods.”
While the technology isn’t new, the application is. The plant would be the world’s first bioleaching facility for the remediation of toxic material. The company initially met with some resistance, however, when it presented its ideas under its other banner, mining firm REBgold Corporation.
“There’s an opinion out there among some people that dealing with a mining company is like dealing with the devil,” says Orr.
The company split into two entities in 2010, with REBgold continuing mining efforts, while BacTech pursued environmental remediation.
Orr says he began his search for toxic tailings that might contain gold by simply Googling “mine tailings” and “arsenic problems.” He quickly found a site located in the community of Snow Lake in Northern Manitoba, about 700 kilometres north of Winnipeg.
“The site was operated as the Nor Acme Mine for 10 years and went broke in 1959,” he says. “It holds 300,000 tonnes of concentrate and contains up to 20 per cent arsenic. The concentrate was stored on site but eventually dumped into the lap of the taxpayer.”
The tailings pile is uncovered and measures between six and 10 metres deep over an area of almost 20,000 square metres. Environmental assessment indicates that acid and arsenic are currently leeching from the stockpile into the surrounding watershed.
After receiving permission to sample the stockpile for gold content, Orr determined that it contained approximately 9.7 grams of gold, or about one-third of an ounce, per tonne. In full production, the plant could net 10,400 oz. of gold per year.
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