An advanced x-ray detection technique could soon be deployed in Australia to ramp up the productivity of local gold mining.
The Commonwealth Scientific and Industrial Research Organisation (CSIRO) has conducted a pilot study in conjunction with Canadian engineering firm Mevex surrounding the use of gamma-activation analysis (GAA) technology to better detect the presence of gold in modest ore samples.
GAA uses high energy x-rays to scan mineral samples of around half a kilo in weight. The interaction of the x-rays with any gold contained by the samples permits it to be detected by highly sophisticated sensors.
The CSIRO study, led by Dr. James Tickner, has found that the method is around two to three times more accurate than the fire assay technique, which is currently widespread in the mining industry, and which requires that samples be heated to temperatures of 1200 degrees Celsius.
According to Tickner, in addition to obviating the need for heavy energy consumption via the extreme heating process, the GAA method is capable of detecting far smaller amounts of gold than conventional methods.
“The big challenge for this project was to push the sensitivity of GAA to detect gold at much lower levels – well below a threshold of one gram per tonne,” Tickner said in an official statement.
Tickner points out that inefficiencies in processing techniques mean that hundreds of millions of dollar of gold go to waste each year, with plants typically only capable of recovering between 65 to 85 per cent of the gold contained by excavated rock.
“Our experience suggests that better process monitoring can help reduce this loss by about a third,” he said.
Tickner said GAA’s other chief advantage is its extremely rapidity and convenience compared to the fire assay method, where results can take several days.
“Using GAA, we can do the analysis in a matter of minutes, allowing companies to respond much more quickly to the data they’re collecting,” he said. “A compact GAA facility could even be trucked out to remote sites for rapid, on-the-spot analysis.”
The technique can also be adapted to other areas aside from gold mining, as it is capable of detecting metals such as silver, lead, zinc, tin copper and the platinum group metals.
The next step for the project is to forge partnerships with both domestic and overseas firms to establish a full-scale analysis facility in Australia, an ambition they hope to fulfill within the next two years.