New gold detection method in development

Researchers from the University of Adelaide are developing a portable, highly sensitive method for gold detection that would allow mineral exploration companies to test for gold on-site at the drilling rig. The method would be particularly advantageous to Australia as the world’s second largest gold producer.

“Gold is not just used for jewellery - it is in high demand for electronics and medical applications around the world - but exploration for gold is extremely challenging, with a desire to detect very low concentrations of gold in host rocks,” said postdoctoral researcher Dr Agnieszka Zuber.

“The presence of gold deep underground is estimated by analysis of rock particles coming out of the drilling holes. But current portable methods for detection are not sensitive enough, and the more sensitive methods require some weeks before results are available.”

Using light in two different processes (fluorescence and absorption), Dr Zuber and her colleagues at the university’s Institute for Photonics and Advanced Sensing (IPAS) have been able to detect gold nanoparticles at detection limits 100 times lower than achievable under current methods. According to Dr Zuber, the team’s easy-to-use sensor will “allow fast detection right at the drill rig with the amount of gold determined within an hour, at much lower cost”.

The researchers have been able to detect less than 100 parts per billion of gold in water. They are now testing using samples of real rock, with initial promising results.

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