Rare earths could be easier to mine than we thought.
Most are unsightly and unnecessary, and they can even be toxic. But the wasteland of 200 years of mining in the region of Australia could be a golden opportunity in the rush for green energy.
A series of supply shocks have awakened the world to the value of critical minerals and rare earths. They are used in the production of light but strong alloys, batteries, electric motors and resilient electronics and are essential for high performance and miniaturized technologies.
But they are hard to find, expensive and dirty to mine and refine, and their supply and prices are extremely volatile.
“About 70-80% of the supply of most of these minerals is controlled by one country – China,” says Mohan Yellishetty, associate professor at Monash University.
But that doesn’t need to be the case. Rich reserves of these minerals lie – above ground – right under our noses.
They are usually found in remote, regional parts of Australia, in the midst of mining boom towns that have seen better days. But those boom days may return, says resource engineering expert Yellishetty.
Much of the environmental and economic cost of extracting these minerals has already been paid. The explosives went off, the drills did their drilling. Diesel was burned to extract the ore from the ground. And it is often already partially refined.
Why start all over again if such easy selections are available?
“If you look at the Olympic dam [in South Australia], which we have studied several times, it could supply quite a large part – up to 40% – of the world’s demand for rare earths,” says Yellishetty. “But only if BHP is happy to collect them.”
Most rare earths and critical minerals are associated with a more common metal. So we know where to look. Olympic Dam, for example, is Australia’s largest copper mine. But associated with copper are the elements yttrium, cobalt and tellurium.
“Currently, no essential minerals are mined,” says Yellishetty. “They all end up in the tailings. So all the hard work of digging them out of the ground is already done. It’s just a matter of finding a business and legal model to refine them.
Australia has started, he adds.
Geoscience Australia’s $225 million Exploring for the Future project is studying national mining waste sites to map their potential.
For example, the Hellyer gold mine in western Tasmania contains some $1.5 billion worth of gold, silver, lead and zinc in its tailings dams.
The Century mine at Lawn Hill in the Gulf country of Queensland has the potential to become the fourth largest zinc mine in the world, thanks to tailings discharge.
Sometimes the results seem to defy logic.
The OneVictorian gold mine, Yellishetty says, sometimes produces particularly high concentrations of antimony. This is necessary for ammo, cables and enamels.
“This is where the relevant legislative/regulatory structure may need to be nimble to accommodate these dynamics so that we can get most of our minerals.”
And this represents a failure of state and national policies. There is no legal way to separately license the recovery rights to these by-products. And exactly who owns and can access what on a disused mine remains to be determined.
But steps are underway to change that, Yellishetty says. A few daring miners and the Exploring for the Future project identify opportunities.
“There are still a lot of details to iron out,” concludes Yellishetty. “But at least there are positive movements. It’s a matter of having something is better than having nothing.