X-RAY technology is set to increase the efficiency of assessing ore grades and reduce mining’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 reduce the environmental impact of mineral processing as it eliminates the need for toxic chemicals and lead.

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The PhotonAssay process where different metals are counted atom-by-atom after unique signatures are produced when a sample is hit with an x-ray beam.

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 and exports.

Chrysos CTO James Tickner said the A$6 million project to take the technology to market would address mineral processing inefficiencies. “Technology is advancing and many industries are getting information in real-time. Down the track we see the technology being deployed to mining sites so that we can provide substantial gains for the industry.

“The current challenge is that methods for analysing gold ore are not fast enough and require too much work. Our process is not new but we have developed it further to be more accurate and it also has potential to assess other metals.”

During the procedure, a sample is put into a plastic screw top jar weighing about 500gm. The jar is placed on a conveyor belt inside Chrysos’ analysis machine where x-rays determine how much gold is in the sample.

Chrysos partnered with CSIRO to trial its technology in Canada and results showed PhotonAssay was able to estimate the measurements of samples down to 30 parts per billion.

The precision level depends on the amount of gold in each sample but for high-grade samples, accuracy was within about 1%.

Ausdrill COO Andrew Broad said the destructive nature of contemporary procedures such as fire assays and the speed of PhotonAssay led the company to partner with Chrysos. “There are two major issues with fire assays – they are laborious and it is difficult to get skilled labour. They take anywhere between 24-48 hours to get results, reduced to just minutes using PhotonAssay. Fire assay is also destructive but with PhotonAssay you can run further tests on a sample at a later date.”

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