Mining waste could be a key source of indium for Australia’s future home-grown solar panel manufacturing industry, and now a new study led by The University of Queensland has investigated indium host minerals at various scales – from centimetres to the nanoscale – helping to find economic ways to extract it and better understand its environmental impact.
In 2024, the Australian government pumped a billion dollars of research funding into a future solar manufacturing industry, but currently most indium – an element prized in solar panels because it conducts electricity and is see-through – is imported from China, where it is a major zinc-refining by-product.
Globally, no mines produce indium as a primary commodity, so to achieve an independent supply chain for Australia, reprocessing old mine waste may supply critical minerals faster than developing new deposits.
To support the search for an Australian source of indium from existing copper and tin deposits, Olivia Mejías, an ARC Centre in Critical Resources for the Future research fellow hosted at UQ’s Sustainable Minerals Institute has been developing tools to identify and characterise indium in mine wastes, bringing this emerging contaminant to the table in discussions about its potential impact on people and landscapes.
In a new scientific paper published in the international journal Science of the Total Environment, Mejías, as first author, and her collaborators applied these tools to find at the Baal Gammon copper mine in north-east Queensland and in the nearby Jamie Creek catchment.
Finding indium
The study found that the Baal Gammon mine waste contains an average of 93 parts per million of indium, more than 1,500 times higher than the usual abundance in the earth’s crust. Importantly, the study also detected polluted waters at the site had levels 24,000 times higher than natural waters.
“We detected indium in the acid mine drainage waters at very high levels; however, there is still a knowledge gap regarding whether it poses a contamination risk,” Mejías said and added that although indium dust is listed by Australian safety authorities as an airborne contaminant, the effects of water-borne indium on livestock, plants, and humans are not well understood, and there are no guidelines to date.
Dr Thomas Poulet, a study co-author, research scientist and team leader at the Commonwealth Scientific and Industrial Research Organisation (CSIRO), explained that studying both extraction and environmental impacts of critical minerals like indium is essential to prevent ecosystem damage and protect water and soil quality.
“Proactive mitigation ensures community trust and preserves companies’ social license to operate while supporting sustainable resource development,” Dr Poulet said.
Paper co-author and UQ Adjunct Associate Professor Anita Parbhakar-Fox said little is known in terms of the environmental impact of indium.
This study highlights a fundamental gap in environmental impact assessments,” she said, “but we anticipate that The University of Queensland will continue to demonstrate leadership in mine waste exploration.”
Mejías suggested that a future research question could be to explore how much indium is around the world and how much has entered the world’s creeks, rivers and oceans.
New technology to find indium
One tricky aspect of working with indium is that X-ray Fluorescence (XRF), the work-horse technology of mineral exploration, doesn’t pick up indium. Instead, Mejías has been working on adapting handheld Laser-Induced Breakdown Spectroscopy (LIBS) technology to detect and quantify indium and other critical minerals.
In October 2025, she recently won the Dan Alexander Memorial Prize, to explore the commercialisation possibilities of this LIBS technology.
As part of her research, Mejías also visited the Australian Synchrotron in Melbourne, where she used X-ray fluorescence microscopy (XFM) at high energies to generate stunning maps showing the distribution of indium at fine scales across a wide range of mine waste samples. This marks the first time that the Australian Synchrotron’s XFM beamline has been used to produce indium distribution maps.
Mine waste key to Mineral Security
Mejías explained that if Australia is going to develop its own supply chains for critical minerals, they will need to find and extract those minerals from mine wastes, in addition to developing known deposits.
“So more than indium, I think the big picture is to highlight the circular economy aspect: to extract and reprocess waste materials,” she said.
“Indium is a key component of solar panels, so if you can extract and use your own resources and you're manufacturing your own product using green energy, it's a win-win!”
Olivia Mejías
