Rare earth elements like those used to make high-powered magnets and the batteries found in electric cars could be extracted from Utah’s existing coal mines. That’s according to an April study led by the University of Utah.
For Assistant Professor of Geology and Geophysics and study co-author Lauren Birgenheier, the research indicates that mining for these rare earth elements “could happen in 5 to 10 years.” But that’s not as simple as it might sound.
“I think the main thing that we don’t know is where is it most viable.”
That means researchers still need to determine if these elements are in high enough concentrations to justify mining for them.
“I can’t calculate a resource volume yet,” she said. “Until we can do that, it is a bit hypothetical.”
In fact, rare earth elements aren’t that “rare” at all.
According to the Science History Institute Museum & Library, some rare earth elements are about as common as copper or tin in the earth’s crust. What makes them rare is that they are seldom found in high concentrations and are usually very difficult to extract and process.
Another motivator for domestic extraction is the vast majority of the world’s rare earth elements are mined and processed overseas, namely in China.
The research also presents an interesting conundrum: these elements that could hasten the transition to more green forms of energy are found in the same place as the fossil fuels they are meant to replace. They are not found in the coal itself, but primarily in shale and siltstone bands immediately above and below coal deposits.
“There’s an obvious tension here in that in our minds we like to categorize fossil fuel based energy, coal, oil and gas. These have high carbon emissions,” Birgenheier said. “If we actually build the infrastructure for the clean energy technologies, we need the resources from the ground to make those things.”
That’s not to say that all mining is bad. In this case, if the concentrations of rare earth elements are found to be economically viable, it could be a positive.
“In general, we support mining where mining is already located,” said Center for Western Priorities Communications Manager Kate Groetzinger.
“We support mining that doesn’t disturb new lands. … And that’s generally a good thing because we do need these rare earth [elements]. We need to get them from somewhere. Why not get them from somewhere that’s already been disturbed?”
Where mining gets tricky is when efforts to access rare earth elements happen alongside mining for fossil fuels.
This year, the Utah Legislature passed laws seen by many as propping up the coal industry — something Birgenheier thinks could, in general, “be helpful in ramping up these secondary development efforts for other types of resources, like critical minerals.”
But that’s not good news for environmental groups like the Center for Western Priorities. For them, any new mining or extended mining for coal — even the kind that could speed up the transition away from fossil fuels — is unacceptable.
“Until we know whether these rare earth deposits are profitable and high quality, there’s really no reason to believe that coal mining should go on just to mine these ore deposits,” Groetzinger said. “It’s essentially like using new printer paper just so you can recycle it. It’s a net zero.”
But coal consumption in the United States is on the decline. As mines continue to close across the country, opportunities to extract these rare earth elements domestically could go along with it.
“I think it would be quite difficult to reopen an underground mine just for this purpose,” Birgenheier said. “Which is really why we focused most of our research on active mines.”
A note of disclosure: Kate Greotzinger is a former KUER reporter.
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Read More: Utah’s coal mines have rare earth elements. Getting to them is another problem