Wrathall also promises his methods will pose no danger to wildlife or drinking water. “We are regulated by the Environment Agency, by UK authorities, and by the Cornwall council,” he adds. “If there were risks, they wouldn’t give us planning permission.”
As regards the general environmental implications of the operation, much is still up in the air. Or, rather, under the ground. Critically it depends on whether the focus of Cornish Lithium – or anyone else – lies on extracting lithium from geothermal brines, or the hard rock. Each have their potential pitfalls, but as regards most criteria, one has rather fewer.
“Relative to hard rock mining, extraction of a metal like lithium from brine I would anticipate there are environmental benefits,” says Paul Lusty, Critical Raw Material Topic Lead for the British Geological Survey. “Much of the discussion and emphasis of Cornish Lithium seems to be on its recovery from metal enriched fluids that naturally exist in the ground. But they’re also interested in the lithium content of mica, one of the main minerals in granite. And they’ve been doing some work on what we term hard rock deposits. They are looking at what we term both types of resources. There’s two very separate approaches.”
Hard rock mining is, as mentioned, a world of holes in the ground, blasting, crushing. Regardless of the visual impact, it’s highly energy intensive. Recovery from brine has many benefits, not least according to Lusty, that prospective developers “don’t have to dig an open pit, and can use directional drilling to access a resource from a point on the surface where there are no restrictions.”
This would typically involve at least two holes, and a circulation system of pumping up lithium-rich brine from a subsurface pool, directing it through a lithium extraction method, then – presumably – re-injecting it into the ground. Possible hazards in this method is that removing pockets of water from the ground can cause pressure changes, which can then cause seismicity – small earthquakes – along faults and fractures. But such hazards, Lusty says, are watched closely.
“They can rarely be detected at the surface,” he says, but are “the reason why there is quite strict monitoring via a seismic network within the UK. Some of the developers also install more extensive seismic networks around project sites.” Such monitoring, he says, would be a regulatory requirement.
In addition, when it comes to lithium mining, as an approach, direct lithium extraction via brine pumping is exploratory territory in itself. “It’s not what you’d call conventional. It’s a fairly new technique,” says Lusty. “There’s probably still some significant development required, depending on the chemistry of the brine.”
