PhotonAssay system quickly tests gold ore (CSIRO)

X-rays for gold

China and Australia are the world’s two largest producers of gold. So, it’s fitting that a device combining Australian and Chinese research, and capabilities in high-tech manufacturing, is set to shake up the industry.

Ore processors need to know how much gold is in their raw material to get the most out of it. The current industry standard for testing ore is the fire assay, an elaborate and time-consuming process that requires temperatures over 1000 degrees and toxic chemicals such as lead. It also takes at least 8 hours to complete.

PhotonAssay system quickly tests gold ore (Credit: CSIRO)

That’s where the PhotonAssay machine comes in. Built by Adelaide’s Chrysos Corporation and Beijing’s Nuctech Company, it uses a two-minute X-ray scan to determine how much gold is in a sample of ore with an accuracy of less than one part in a million.

The concept was developed over a decade by James Tickner and colleagues at CSIRO: you bombard the ore with high-energy X-rays, and then identify gold by the characteristic gamma-ray echo it gives off in response.

The idea had such potential that a new company, Chrysos, was formed to develop it. For manufacturing smarts, James turned for assistance to Nuctech, a world-leading maker of security scanners. He has worked with the Chinese company since 2007, when they collaborated with CSIRO to produce an innovative neutron-based scanner for air cargo.

The air cargo scanner project led to other cooperative research and development projects. Over the years, James has made dozens of trips to visit Nuctech’s Beijing headquarters and their development and production facility in Miyun.

Teaming up with Nuctech engineers, Chrysos developed a design for the PhotonAssay machine in early 2017. Just over a year later, the first device began operation in Perth. Another two

PhotonAssay machines will be deployed in the first half of 2019, and after that Chrysos will ramp up production.

“Nuctech have given this project all the resources it needed to succeed,” says Chrysos CEO Dirk Treasure. “There’s no better party we could have chosen to work with.”

Making mines safer

Huainan Coal Mining Group is going deeper each year in the search for coal. Its miners are often working at depths of nearly a kilometre. Australia’s CSIRO is working with them to ensure the safety of the mines.

Coal seams in the Huainan area are highly gassy. That creates two major risks: explosive outbursts of coal and gas; and concentrations of methane gas.

Credit: Shutterstock

Traditionally miners have dealt with the methane after it has been released. The Huainan and CSIRO engineers looked at the problem differently and have developed a system that enables them to drain methane from the coal seam.

This approach was used at the Huainan Pansan mine and generated a consistent, high flow rate of high purity gas. It also helped CSIRO develop a similar approach for the Bulga coal mine in eastern Australia.

The Huainan and CSIRO team have also demonstrated that waste methane gas could be used to produce electricity using a novel catalytic combustion gas turbine system.

Automation for safety

Longwall automation at work (Credit: CSIRO)

Most underground coal mines use longwall mining. Typically, a seam of coal is mined in a series of one metre slices, taken from a block of coal that’s kilometres in length and hundreds of metres deep. The coal is carried away on a belt, and the roof of the mine is held up over the top of the equipment by large hydraulic rams. This mining system has made mines safer, but it still puts miners close to big, violent machines. “So, we worked with industry to create an underground automation system that isolates people from mining hazards while improving productivity,” says CSIRO’s Dr Mark Dunn. The machine knows where it is to the nearest centimetre using a built in guidance system that works underground. The system can be managed by an operator in the mine, on the surface or on the other side of the world.

Sixty per cent of Australia’s underground coal miners already use the CSIRO technology. China’s biggest miner, the China Energy Investment Corporation (China Energy), has installed five systems and China Coal Technology and Engineering Group is working with CSIRO to make the technology available to the 1,500 longwall mining sites in China.

For further information visit

Header image from Shutterstock