Lithium and the dream of Cornwall’s mining revival

Lithium, the lightest metal element, is a vital resource for the energy transition. It is used in batteries for EVs and grid-scale energy storage – a single Tesla Model S battery contains 12kg of lithium.

Cornwall happens to be sitting on a massive lithium deposit, prompting former Prime Minister Boris Johnson to describe it as the "Klondike of lithium". Would-be miners – most notably the companies British Lithium and Cornish Lithium, both based in the county – have descended on the Cornish landscape, poring over old geological maps to search for buried treasure. At present, there is no full-scale operation or any certainty of a full-scale operation. However, pilot projects have yielded encouraging results, and the companies hope that by 2030 they could be extracting thousands of tonnes of lithium every year.

There is sincere hope that this will come to fruition. Cornwall's mining heritage reaches back to the Bronze Age. Its landscape is so sculpted by abandoned mines that the Cornwall and West Devon Mining Landscape was recognised as a Unesco World Heritage Site in 2006. However, the decline of its mining industries through the 20th century has left it the second poorest area in Northern Europe, in no small part dependent on tourism and, until recently, EU funding. The dream is that the Cornish mining industry might be revived – this time, without harming its people and environment – and become an important part of that green industrial revolution the UK has been promised.

The energy transition is driving demand for lithium to unprecedented heights. According to US-based alliance Li-Bridge, demand for lithium-ion batteries in the US alone is set to grow sixfold by 2030. "I think the world has realised that lithium is obviously an essential element, and demand is going to go up massively," says Jeremy Wrathall, CEO of Cornish Lithium. "We're talking about five million tonnes of [annual] demand by 2035."

At present, lithium production is dominated by a few countries. Australia is the leader (approaching 100,000 tonnes of annual production), followed by Chile, China, Argentina, Zimbabwe and Portugal. Not unusually for energy transition metal mining, lithium mining often comes at great environmental and human cost. Geothermal lithium extraction as performed in South America, for instance, involves laying out lithium-rich brine in colossal evaporation pools beneath the Atacama sun. In Chile's lithium-rich Salar de Atacama salt flat, mining activities consume almost two-thirds of the area's water, contributing to devastating water shortages. There is an increasing feeling that lithium mining must be carried out more responsibly if the world is to reap its benefits fully. This could be an opportunity for the UK to distinguish itself. It would have a long way to go to catch up with the big lithium producers in terms of volume, but it may be able to mine the world's most sustainable lithium.

Of course, there are other reasons why the UK government might be interested in domestic lithium production. The US and its allies are scrambling to establish supply chains for technologies of strategic importance – from solar panels to semiconductors – that circumvent China, which is the world leader in both raw critical minerals and lithium-ion battery production. Domestic lithium mining, along with domestic battery manufacturing, would be strongly in the UK's geopolitical interests. Then-minister Nadhim Zahawi said in 2020: "The potential to become self-sufficient in lithium, which Cornish mining represents, will, I think, be incredibly important to the British economy."

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There are two potential avenues for lithium production: hard-rock mining and direct extraction from brines. The more traditional approach is hard-rock mining. This involves digging rocks, crushing and grinding them to separate the lithium micas (a group of pinkish minerals rich in the element), then subjecting them to various processes to extract the lithium.

Both British Lithium and Cornish Lithium are experimenting with hard-rock mining around St Austell. The former is using its own patented technology for the extraction stage, and the latter is using technology from Australia-based Lepidico. Both companies seem confident. Notably, British Lithium has identified a suitable lithium resource in a former china clay mine which could support annual production of 20,000 tonnes of lithium – enough to meet a third of national demand around the end of the decade.

Whether lithium extracted via hard-rock mining can be considered sustainable hinges mainly on the question of energy. All of that crushing and grinding is incredibly energy-intensive. British Lithium acknowledged in a 2021 interview that if it and Cornish Lithium ran operations concurrently, they would overload the grid. Hopefully, nothing of the sort will come to pass. Both companies are interested in establishing private power networks supplied by local renewable resources like solar and offshore wind (Imerys, which carries out related operations in Cornwall, already has its own private network).

In 1864, a brine 'rich in Lithia' was discovered in a mine near Redruth. Cornwall sits on a 280-million-year-old granite sheet, through which water has trickled, absorbing and dissolving lithium in its path. This leaves lithium-rich springs beneath the Cornish landscape. With hard-rock mining, Wrathall says, the rock must be cracked to get the lithium solution out, but, with these brines "nature has already done it for you".

Extracting lithium from brine is a more experimental approach. Cornish Lithium, which is attempting it, prefers not to call it 'mining' at all. The company aims to take brine up to ground level, directly extract the lithium (concentrating the brine via reverse osmosis, followed by an extraction step), then put it back in the ground. This could be a remarkably undisruptive way to produce lithium. In terms of infrastructure, it would require little more than a shed-sized plant and two boreholes: one to collect the brine and one to return it. In 2020, the company confirmed it had found 'globally significant' levels of lithium in waters under Cornwall. It recently drilled its third borehole and hopes to have small-scale production (up to 300-500 tonnes a year) running by 2025.

Cornish brines are much less lithium rich than South American brines (220-260mg/L vs 2,000mg/L), but have certain advantages that bode well for sustainability. Elsewhere in the world, these brines surface at very high temperatures and need to be kept under high temperature and pressure to prevent the dissolved solids from crystallising. Cornish brines surface at just 80°C, making them easier and more energy-efficient to process. While not hot enough for geothermal power generation, they are hot enough for district heating networks. Cornish Lithium is already supplying some heat to local clotted cream company Rodda's and is discussing the possibility of providing heat for greenhouses.

Professor Karen Hudson-Edwards of Camborne School of Mines, an expert in sustainable mining, acknowledges that further work could be needed to ensure this process is truly sustainable – such as understanding the impacts of changing the chemical composition of these brines – but concludes: "In terms of overall impact I think geothermal lithium mining is as sustainable as we can get. It's not going to create a lot of waste, the footprint is small, and Cornish Lithium are very committed to sustainability, so that's a big plus as well.

"Mining has a bad reputation with many people, for [good] reasons. Really, it has not been a great performer in the past but I think the companies are waking up to the fact that people are demanding – well, insisting on – sustainability and good practice or they won't fund the mining companies if they don't do that. Things are changing quickly."

Thanks to its natural resources and the sincerity of the companies involved, there is plenty of potential for sustainable lithium mining in Cornwall. Some hope that this – along with renewables and perhaps even a battery factory (St Austell and Newquay MP Steve Double has pressed the government on the possibility) – could place Cornwall at the forefront of a green industrial revolution that is good for the economy, communities in deindustrialised areas, and the environment.

"I absolutely, categorically do think [lithium extraction] could be part of a green revolution in Cornwall," Wrathall says. Among other benefits, he emphasises that lithium production could offer a great incentive for ambitious young people to stay in their home county.

This is a critical consideration. There is a strong feeling that Cornwall must benefit from this mining revival, rather than having its labour and resources exploited by others (this is complicated by big questions about land ownership, still dominated in the county by hereditary landowners like the Duchy of Cornwall). An important part of ensuring that Cornwall benefits from lithium mining is investing in skills and infrastructure to support the industry. "The metal might be in the ground; you might be able to extract it technologically and economically, but we've got skills gaps at the moment. [Local] people haven't had the opportunity to study and get to a stage where they would be able to easily or naturally go into these jobs," says Dr Eva Marquis, also of Camborne School of Mines.

"Then you've got a social tension if you can't get people in the county with the right skillset and you want to get these mines up and running in the next five to 10 years. If you don't invest in the talent pipeline now, you're [...] going to have to bring people in, and that will probably skew the social divide even more. There would be some benefit to having more people down here but we're already in a housing crisis, so there are lots of underlying challenges."

The amount of work required to make the most of Cornwall's lithium deposits should not be underestimated. It will be a complex, costly endeavour and inherently risky – will markets be willing to pay a large enough green premium to make it economically feasible? The recent collapse of lithium-ion battery start-up Britishvolt, before it was bought out of administration by an Australian firm, should remind us to take nothing for granted.

Experts agree that the challenge is bigger than the main two companies involved, and call for a clear, coordinated strategy to support this green industry and others. Wrathall says: "It doesn't help that our government hasn't got an industrial strategy. If we're to retain the car industry in the UK, that would be helpful. The odds are against us at the moment, but I think Cornwall has got the potential to restore its legacy of innovation and technological leadership."