GAA works by scanning mineral samples, typically weighing around half a kilogram, using high-energy x-rays similar to those used in hospitals. The x-rays activate any gold in the sample, and the activation is then picked up using a sensitive detector. According to project leader, James Tickner, CSIRO’s study showed that this method is two-to-three times more accurate than the standard industry technique “fire assay,” which requires samples to be heated to 1200°C.
Tickner explains that a gold processing plant may only recover between 65-85% of gold present in mined rock. Given that a typical plant produces around AUD $1 billion of gold each year, this means hundreds of millions of dollars’ worth of gold is going to waste.
One major benefit of GAA is that it is easily automated, allowing for much quicker analysis of ore samples. It is also more sustainable—no use of heavy metals such as lead is required. It is also very adaptable. “While most of the work we’ve done has been based on the gold industry, the technique can be modified for other valuable commodities such as silver, lead, zinc, tin, copper, and the platinum group metals,” says Tickner. For more information: James Tickner, 618/8303-8430, [email protected], www.csiro.au.
