“Globally significant” deposits of lithium in Cornwall could meet future UK demand

Cornwall is famous for its millennia-old tin mining industry which has supported the county industrially for hundreds of years until its demise in the early 20^th century. Now, explorative mining has found huge deposits of lithium which could spark a renaissance in Cornish mining but also support the UK’s EV industry.

Exploration of lithium deposits started almost two years ago, but it wasn’t until the autumn of 2020 that Cornish Lithium announced it had struck upon “globally significant” deposits of the metal at a site just north of Redruth. Samples were taken from between 600m and 5.2km in the ground and the result was very positive: concentrations of 220mg/l with low levels of other metals, such as magnesium, which make extraction more difficult.

Cornish Lithium’s Chief Executive said: “Initial results indicate some of the world’s highest grades of lithium and best overall qualities encountered in published records for geothermal waters anywhere in the world.”

The reason behind the high concentrations of lithium in Cornwall is all down to the county’s geology. Lithium is typically found in hard rock areas, often below dried lake beds in brine reservoirs. In countries such as Australia, Chile and other South American producers, large open cast mines have a huge environmental impact, and separating the valuable metal from the rock requires a huge amount of water and heat generated using fossil fuels.

In places like this, up to 15 tonnes of CO2 is released for every tonne of lithium extracted.

The lithium below Cornwall is found in geothermal briny waters, kept extremely hot and under high pressure thanks to naturally occurring geothermal energy. Extracting lithium from a source such as this is extremely clean in comparison to other methods as the heat and water required is already there in-situ, powered by natural processes.

There’s an additional benefit too: free power. Cornish Lithium said: “The same water can be used to generate zero-carbon electrical power and heat. As such, these waters are rapidly becoming recognised as the ultimate ethical source of lithium.”

At the concentration of 220 milligrams per litre, and with pressure pushing the brine at between 50 litres per seconds, a smartphone battery’s worth of lithium is produced every few seconds. A little while longer and you’ve got the amount required for an EV.

The need for battery independence

In January we reported how the Brexit deal that has been struck essentially gives UK car makers three years to source batteries from UK-based manufacturers if they are to avoid getting stung by tariffs.

Around 130GWh of production will be needed domestically to reach so-called battery independence and at the moment, the only Gigafactory that seems to be taking shape – that being built by Britishvolt – will have a 30GWh capacity by the end of 2023. And Britishvolt would be importing almost all of the raw materials required to build batteries, which obviously comes at a grim environmental cost.

According to Simon Moores, MD of the consultancy Benchmark Minerals, and speaking in the Financial Times, “if possible the UK should get 25 per cent of its raw materials domestically in the next ten years. It’s a good goal to invest in domestic UK sources and extraction technology.”

To fulfil the UK’s lithium needs by 2035, The Faraday Institute reckons we’ll need 59,000 tonnes per year. Cornish Lithium estimates that it can extract more than a third of this (20,800 tonnes) per year from its operations. What’s more, vehicle manufacturers across the world – such as Volkswagen, which is supporting lithium mining exploration in Germany – wants its batteries to be produced cleanly, so the pressure is on from the companies using the raw product to ensure it’s created cleanly.

A return of mining in the West Country

Cornish Lithium is joined by rival company, British Lithium, in wanting to explore and exploit the opportunity to bring mining back to Cornwall and the surrounding areas. From Devon in the east to under the sea between Cornwall and the Isles of Scilly in the west, there is a lot of ‘green’ lithium there for the taking.

British Lithium reckons it can have a conventional open-pit mine operational by 2023, but to get the more sustainable mining underway, more investment from the government and wider industry is needed. Cooperation from a wary local population is also needed. However, given the fact that lithium is going to be a requirement in achieving a low-carbon economy between now and 2050, it seems unlikely that the investment won’t be forthcoming.