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X-rays could help detect gold, CSIRO says

Scientists at the CSIRO say shooting x-rays at chunks of ore could detect far more gold than the current industry standard, saving billions of dollars.

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Source: AAP


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Zapping rocks with x-rays could stop hundreds of millions of dollars worth of gold going back into the ground, the CSIRO says.

Scientists have fine-tuned a method called gamma-activation analysis, which they say is far better at detecting gold than the current industry standard.

It uses a metre-long tube to shoot high-powered x-rays - like those used to treat cancer patients - into fist-sized samples of ore.

The rays activate traces of gold which are then read by a detector.

The technique is faster and more accurate than the industry standard for detecting gold, said Dr James Tickner, a science leader at CSIRO.

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That method, called fire assay, puts tablespoon-sized samples through lengthy chemical tests.

It's slow and because it uses such small samples, can often miss gold traces, he said.

"Often only 65 to 85 per cent of the gold is recovered, and the rest eventually goes back into the ground."

The x-ray method could reduce those losses by a third, he said.

"Australia produces about $10 billion worth of gold per year, so even a few per cent saving on the amount you extract quickly becomes hundred of millions of dollars a year."

One of the challenges of gold mining is that is exists in minute quantities of about one gram per tonne of ore.

The Russian scientists who originally pioneered the method struggled to get the sensitivity to acceptable levels.

"We think that's a problem we've cracked," Tickner says.

The CSIRO is looking to partner with companies to get a facility up and running within two years.


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