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Published 17 May 2012 05:06, Updated 17 May 2012 11:52
Business efficiency and environmental benefit don’t have to be mutually exclusive. Proto Resources and Investments has developed a way of dealing with waste in tailings dams for nickel mining that is both cheaper and more environmentally beneficial.
“It makes no sense to pour iron suphate into tailings dams,” says Andrew Mortimer, who co-developed the technology which Proto plans to use on its flagship Barnes Hill nickel project in Tasmania.
“For one thing you have to invest in acid [to treat it]. So I said: “Let’s chop the iron sulphate molecule in half with electricity and produce an iron product. The lab said it wouldn’t work and refused to do the testing for three months.”
Mortimer was able to prove his process worked and the company developed a technology that reduces the cost of production. “You see with sites like Ravensthorpe (nickel mine in Western Australia), they have to make massive capital expenditures, meaning they can only make money years later in the cycle. We said we have to find a low capex [capital expenditure] approach that reduces the cycle. We also needed to drive down acid usage.”
Mortimer says the process retrieves the acid and the iron product is highly magnetic so it is easy to separate into its constituent parts, including magnesium.
“And you don’t have to store it – the storage alone can send you bankrupt. Everyone wants to crack this problem. As people become more interested in preserving the environment, they are not going to tolerate these tailings dams,” Mortimer says.
“I saw one that went for 10 kilometres – it was impressive. [Taking this approach] makes so much more sense, both from a moral and financial perspective.”
Mortimer says the process goes through five stages and that the electricity creates a high pH (alkaline) product in a low pH (acidic) solution.
“The Tasmanian government said: ‘We are not going to stop you doing this project [Barnes Hill] but can you make it as clean as possible.” He says the process could potentially be applied to bigger projects such as the Olympic Dam mine in South Australia.