Cornish Lithium Ltd says it has found ‘globally significant’ deposits of valuable mineral used in automotive industry.

A mining company has found “globally significant” deposits of valuable lithium in Cornwall and is preparing to start work on a £4million pilot plant to extract the mineral.

Cornish Lithium Ltd, a mineral exploration company hunting for “battery metals” in the South West, said the results from preliminary sampling of lithium in deep geothermal waters at the United

Downs Deep Geothermal Power Project near Redruth, Cornwall, indicate some of the highest grades of lithium found anywhere in the world.

Geothermal waters which contain lithium are different from other occurrences in brine given that 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, the company said.

Jeremy Wrathall, chief executive and founder of Cornish Lithium, said: “This is an exciting step towards the realisation of low-carbon lithium extraction from geothermal waters in Cornwall, and compliments Cornish Lithium’s work to date on exploring for lithium contained within shallower geothermal waters in the County.

“The pilot lithium extraction plant, part funded by the UK Government, that we will develop with Geothermal Engineering Ltd. at the United Downs Deep Geothermal Power Project will allow us to evaluate green Direct Lithium Extraction technologies which will bring us another step closer to commercial production of lithium in Cornwall.

“We now have increased confidence that these lithium-enriched geothermal waters can be found at depth across Cornwall and believe that there is significant potential to replicate combined lithium and geothermal extraction plants in different locations across the County where Cornish Lithium has mineral rights agreements in place”

The company, in collaboration with Geothermal Engineering Ltd (GEL), the developer of the United Downs Geothermal Power Project, was recently awarded funding from the Government’s Getting Building Fund to build a pilot lithium extraction plant at the United Downs site.

The £4million project will design, procure and build a pilot plant to trial Direct Lithium Extraction (DLE) technology to extract lithium from the geothermal waters which circulate naturally at depth in the granite rock that underlies Cornwall.

The initial assay results show lithium concentrations of up to 260mg/L, which are believed to be amongst the highest published grades of lithium in geothermal waters globally.

Importantly, the Total Dissolved Solids (TDS) content of these Cornish waters is exceptionally low relative to other geothermal waters worldwide, making Cornish waters globally significant. In particular, magnesium, a metal that makes processing more difficult and expensive, is extremely low.

These results are considered highly encouraging by the firm given current developments in lithium extraction using DLE technologies. Additional testing is planned.

DLE technology extracts dissolved lithium compounds from water without the need for the large evaporation ponds used in the arid regions of South America.

DLE technology uses ionic adsorbents and/or ion exchange membranes, with the residual water being returned to depth via a borehole.

Using DLE technology the company aims to maximise product recovery from the geothermal waters in a small footprint, energy efficient extraction plant which will be powered by an on-site geothermal power plant.

The pilot plant at the United Downs Deep Geothermal Power Project will allow detailed evaluation of potential processing methodologies and accelerate efforts towards commercial production of lithium.

Low-carbon lithium extraction from geothermal waters should make this a very compelling supply of lithium for automotive manufacturers seeking low carbon supply chains of battery metals, the firm said.

Mr Wrathall added: “These results show that Cornish deep geothermal waters, unlike others around the world, have low salinity, meaning much lower concentrations of elements such as magnesium and sodium.

“When these elements are present in high concentrations it can make it difficult and more expensive to separate out the lithium compounds. Cornish geothermal waters should therefore be highly suitable for extraction methods using DLE technology.”

The results from the United Downs Geothermal Power Project demonstrate that this geothermal system has realistic potential to produce economic grades of lithium and, potentially, additional by-products.

Cornish Lithium assayed the samples at two separate independent laboratories to confirm the grades and the results verify the accuracy of historic samples identified in other locations across Cornwall.

Next steps include further sampling of the deep geothermal waters when GEL commences its next phase of test work at the United Downs site in October, with further tests expected to provide additional observations regarding the origins and context of these deeper geothermal waters.

The information from additional bulk samples will then be used to inform the design and technology for the pilot DLE plant.

Rob Bowell, who has been involved in development, design and review of lithium and salt extraction projects in South America, Mexico, Nevada, Tibet, Africa, India and Europe and is Corporate Consultant with SRK Consulting, said: “The lithium grades reported from the deep geothermal waters at United Downs are globally significant. Coupled with the low salinity of the waters, they should be highly amenable to lithium extraction using cutting-edge DLE technology.

“This is a fantastic opportunity for Cornwall to lead the charge on environmentally-responsible extraction of this critical raw material in Europe and beyond.”

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