Coal ash is usually the stuff of headaches — dust, dams and long-term rehabilitation bills. But new research out of Monash University suggests it could be something else entirely: a ready-made stockpile of rare earth elements (REEs).
Monash engineers say their process can extract all 17 REEs from fly ash, tailings and even e-waste, with more than 90% efficiency. Crucially, the brown coal ash that fills Victorian storage ponds is free of the radioactive elements that complicate conventional rare earth mining.
“From coal fly ash alone, we could recover up to 45,000 tonnes of rare earth metal each year,” Monash University research fellow Bennet Thomas and Professor Sankar Bhattacharya, who led the project, wrote in a recent article. “That’s more than twice what Australia produced in 2021, and nearly 30% of current global production. That amount of rare earth metal is enough to make the magnets needed for about 15 million electric vehicles.”
‘Mining without mining’
The Monash team has already scaled up its technology from a bench-top experiment to a 30-litre system, and is now building a 100-litre semi-continuous unit with plans for a demonstration plant on campus. Their process has won awards and is attracting industry and government interest, underlining the momentum behind what they call “urban mining.”
The approach offers some clear advantages. Feedstock is consistent and abundant: Australia’s coal-fired power stations generate more than a million tonnes of fly ash annually in Victoria alone. Stockpiles are already sitting in ash ponds across the country, eliminating exploration risk and the decade-long lead times of a new mine.
Scott North, co-founder of Kamoa Capital, said the findings “could be the start of a whole new subsector — ‘mining without mining coal’”. In a recent LinkedIn post, he noted:
“If this process really works at scale, you’re talking about flipping a liability into an asset. Logistics are already in place, the feed source is consistent, and there’s no exploration risk.
“My question is economics,” he added. “Can you do it cheap enough to compete with conventional supply, especially with China still controlling the bulk of the REE market?”
That cost question looms large. New mines typically take 10 to 15 years and billions in capital before they produce their first tonne. A process that reuses coal ash could shortcut much of that timeline — but it still needs to prove economic viability at scale.
China tightens the spigot
The research comes as Beijing announces fresh curbs on rare earth export quotas, reinforcing its grip on a market where it already handles around 90% of refining.
The latest restrictions come as Chinese domestic demand grows and as geopolitical tensions remain high, particularly with the United States.
Analysts warn that supply squeezes have historically caused price spikes and downstream uncertainty for EV and defence supply chains. By leaning on urban mining, Australia and other producers could reduce vulnerability to these swings — but getting to market quickly is key.
Washington’s shifting playbook
Meanwhile, the US is also rethinking its critical minerals strategy. The Trump administration is reviewing the US Geological Survey’s list of critical minerals, with industry observers expecting rare earths, gallium and graphite to remain at the top of Washington’s security agenda.
On Capitol Hill, Senators Mike Lee and Mark Kelly have introduced a bipartisan bill to accelerate domestic processing capacity and reduce reliance on Chinese supply. At the same time, the US Interior Department is prioritising recovery of minerals from mine waste — echoing Monash’s “urban mining” concept.
This alignment of policy and research signals a potential shift toward more circular resource strategies. Where once coal ash was a clean-up liability, it could become part of the critical minerals pipeline.
Australia’s role in a fractured market
Australia has already positioned itself as a trusted partner in critical minerals, underscored by recent momentum towards the setting of a rare earths price floor similar to what the US has in place, which has boosted prospects for local projects such as Lynas’ rare earth operations in WA and Iluka’s refinery project at Eneabba.
But as Monash’s Thomas and Bhattacharya research shows, urban mining may offer a way to accelerate supply without the decade-long wait for new mines.
“It’s an opportunity to reshape how Australia thinks about resources,” they wrote. “By treating these stockpiles as a resource, not waste, we can make immediate use of existing materials while avoiding the environmental footprint of new mining.”
With global demand for EVs, wind power and defence technology rising fast, supply gaps are inevitable. If Monash’s method can move beyond the lab and into industrial deployment, Australia could add a new layer to its critical minerals story — one built not on digging deeper, but on rethinking the resources already at hand.