A COMPANY that has been exploring for lithium near Redruth says it has found some of the world's highest grades of the metal.

Cornish Lithium Ltd says results from preliminary sampling of lithium – which is used in batteries from electric cars to household appliances – in deep geothermal waters at the United Downs Deep Geothermal Power Project, Gwennap, "indicate some of the world’s highest grades of lithium and best overall chemical qualities encountered in published records for geothermal waters anywhere in the world".

Geothermal waters which contain lithium are very different from other occurrences of lithium 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, CEO 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.”

Falmouth Packet:

Jeremy Wrathall

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

The £4 million 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 260 mg/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 at a concentration of only 5mg/L.

Additional testing is planned over coming weeks.

DLE technology extracts dissolved lithium compounds from the water without the need for the large evaporation ponds that are 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 Cornish Lithium 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 compelling supply of lithium for automotive manufactures seeking low carbon supply chains of battery metals.

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.

The company assayed the samples at two separate independent laboratories to confirm the grades.

The results from the United Downs Geothermal Power Project also verify the accuracy of historic samples identified by Cornish Lithium 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.

Dr Rob Bowell, of SRK Consulting, is the Qualified Person for Cornish Lithium’s geothermal water project.

He 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.”