High-speed gold analysis process becomes commercial reality
Invented by Australia’s national science agency CSIRO and brought to market by Chrysos Corporation in Adelaide, photon gold analyses is a faster, safer and more environmentally-friendly alternative to the conventional fire assay technique for gold analysis.
Chrysos CEO Dirk Treasure said the first PhotonAssay Max system is now operating at Ausdrill’s MinAnalytical facility in Perth, Western Australia, with two more systems to be established in the Kalgoorlie goldfields in the coming months.
“With the first system now up and running at Ausdrill, we have successfully progressed the photon assay technology from concept through to a deployed product in just 16 months,” Treasure said.
“We’ve taken the big step from being an R&D company to an equipment supplier.”
CSIRO research program director Nick Cutmore said the system was developed after it was recognised there was a market need for innovative data solutions to drive better and faster decision making across the minerals value chain.
“The result is a technology export opportunity for Australia worth $1 billion in gold mining alone, and a competitive edge for Australia’s mining industry on the global stage,” Cutmore said.
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 helps to reduce the environmental impact of mineral processing because it eliminates the need for toxic chemicals and lead.
During the PhotonAssay procedure, a 500g sample is put into a plastic screw top jar.
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 PA1408X system installed in Perth can analyse 72 samples per hour and gold can be assayed down to levels of 0.03 parts-per-million.
The level of precision depends on the amount of gold in each sample but for high-grade samples, accuracy is within about one per cent.
Loading and analysis is carried out robotically, and digital results are reported directly to clients or passed to existing laboratory information management systems.
Treasure said the PhotonAssay system also eliminated the destructive nature of fire assays and was much quicker.
“Analysis takes two to three minutes compared with the six or more hours for fire assays,” he said.
“This (quick results) will become even more important as the industry picks up and the turn around time for fire assay increases.”
The PhotonAssay process does not destroy the sample so further tests can be done on a sample at a later date.
The system will analyse at least 50,000 gold samples a month and can also be applied to a range of other minerals, including silver and copper.
Treasure said Chrysos has set up a leasing model that was of comparable cost to fire assays.
“Our lease model has been well received by the industry, with photon assay technology benefits being delivered without any increase in operating or capital costs,” he said.
Ausdrill has plans to install a PhotonAssay Max to service its mines in Africa and Chrysos is now developing mine site and mobile models of the technology.