Trelavour Hard Rock Lithium Project
The Trelavour Project repurposes a former kaolin pit near St Austell where lithium is present in mica minerals within the granite.
In 2018 and 2019 Cornish Lithium began onsite surface exploration at its hard rock lithium project at Trelavour Downs near St Dennis. Project identification resulted from extensive research into historical records, and modern geological, geochemical, and geophysical datasets. It is notable that lithium was successfully mined in the Trelavour Downs area during the second world war. This initial work identified the Trelavour Downs kaolin (china clay) pit as a high-priority site for exploration and development.
Initial drilling of the site in 2020 confirmed the presence of pervasive lithium mineralisation in the form of lithium bearing micas within the granite that were identified as amenable to extraction in initial successful laboratory metallurgical trials.
Lithium will be extracted from Trelavour ore utilising concentration to a lithium mica concentrate followed by lithium extraction via a licenced process developed by Australian company Lepidico, to produce battery grade lithium hydroxide. Cornish Lithium has acquired an exclusive licence to use Lepidico’s technology across the St Austell region.
The Lepidico process is a low-energy, ambient condition leach using conventional industrial equipment. Lepidico’s case studies have demonstrated lower energy consumption and lower capital and operating costs for the technology compared to other known processing routes. This is in keeping with the Company’s strategy of enabling a decarbonisation of the lithium supply chain.
Resource drilling in 2021 led to the publication of a maiden JORC-compliant Inferred Resource of 51.7 million tonnes at a grade of 0.24% lithium oxide equating to over 300,000 tonnes of contained Lithium Carbonate Equivalent. Based on the resource estimate, extensive metallurgical testwork and engineering studies, Cornish Lithium completed a scoping study in 2022 with the following highlights:
- 20-year mine life with average production of 7,800 tpa of lithium hydroxide
- Post-tax NPV (8%) of US$318.6 million and IRR of 24.4%
- Initial capital expenditure of US$243.8 million
- Payback within 3.8 years from first production
Whilst the Scoping Study includes the capital expenditure to produce a number of by-products such as caesium and rubidium, the current results do not include the additional revenue from such by-products. Test work is currently being completed that will allow their additional value to the project to be estimated.
Cornish Lithium has secured the Trelavour Downs site along with the nearby TreLith Processing area, which is a brownfield industrial site, which benefits from excellent logistics and existing infrastructure, including power, rail, road and access to port facilities.
Environmental surveys and studies have commenced to support the project’s Feasibility Study together with a drilling programme designed to expand the Trelavour Mineral Resource and allow conversion from Inferred to a Measured and Indicated classification under the JORC Code.
Detailed engineering of a demonstration plant is underway and construction at the TreLith site will commence shortly. This will validate the process flow sheet and will advance progress the Company’s plans to be in production in 2026.