Accurate gold assessment without fire assays is on the horizon.
HIGH-POWERED x-ray technology from Australia is set to increase the efficiency of assessing ore grades and reduce the mining industry’s environmental footprint.
South Australian company Chrysos has developed a gold analysis process that is up to three times more accurate than conventional methods.
PhotonAssay uses high powered x-ray machines to activate the gold in a given sample and measure the signal it gives off to quickly and accurately quantify how much gold is present. The process also helps to reduce the environmental impact of mineral processing because it eliminates the need for toxic chemicals and lead.
Chrysos is setting up its first production unit in Western Australia, working in partnership with Ausdrill and MinAnalytical. The company aims to have a smaller on-site model available next year to better support in-field exploration campaigns and make exporting its technology easier.
During the PhotonAssay procedure, a sample is put into a plastic screw top jar weighing about half a kilogram. The jar is then placed on a conveyor belt inside Chrysos’ analysis machine where x-rays determine how much gold is in the sample. The level of precision depends on the amount of gold in each sample but for high grade samples, the accuracy was within about 1%.
In tests with the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Canada last year, PhotonAssay was able to estimate the measurements of samples down to 30 ppb.
Find details of the PhotonAssay technology at http://Chrysos.com.au/.