Sunday, 23 December 2012

Monash mining expert examines Wiluna uranium proposal

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yellow cake“How the mine will manage tailings—it’s not clear how that will happen effectively." —Mr Mudd. Image: Uranium Energy AN AUSTRALIAN expert on mining sustainability has highlighted some of the key environmental aspects for West Australia, as the state moves closer to its first uranium mine.

Resources company Toro Energy recently received state government environmental approval to develop WA’s first uranium mine near Wiluna, with the company now seeking federal environmental approval.

Monash University mining expert Gavin Mudd says the primary issues concern the management of tailings and waste rock, as well as water use, contamination and other aspects local to the mine site.

“How the mine will manage tailings—it’s not clear how that will happen effectively. There are some viable strategies in place, such as back filling the pit with tailings as the process occurs,” he says.

“But there hasn’t been any clear, convincing information as to what the chemistry would be, or the fact that it really will be stable for 10,000 years or more.

“Waste rock also is an important issue, as leaching off of waste rock includes low grade uranium so any water that leaches has to be managed and treated.

“At the Rum Jungle uranium mine for example, there has been massive amounts of acid rock drainage that has leaked uranium and a range of heavy metals and salts directly into nearby river systems.”

In granting approval, WA Environment minister Bill Marmion said Toro Energy will be required to research the water requirements of groundwater-dependent vegetation and more closely monitor stygofauna in the three calcrete ecosystems that would be partially impacted by the proposal.

“The new conditions will strengthen protection of stygofauna and groundwater-dependent vegetation, including Tecticornia samphires, and better address surface water flows,” he says.

Dr Mudd also highlighted the use and contamination of ground water sources in the area as a key issue, saying there have been issues at other uranium mines across Australia and it remains unclear where water for this site will come from or what techniques will be used to source it.

“At the Beverly uranium mine in South Australia, acid leach mining is permitted, which requires injecting sulphuric acid into the ground water to dissolve uranium and then pumping that back out to the surface for extraction.”

“It’s quite an easy process for deposits such as Beverly but it does leave massive contamination in ground water.”

Toro Energy Limited proposes to produce up to 1,200 tonnes per year of uranium oxide concentrate over an anticipated mine life of 10 years, from the Centipede and Lake Way deposits, approximately 30km south and 15km south-east of Wiluna.

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