The Trelavour hard rock lithium project is located at St Dennis in the St Austell region of Cornwall. Mineralisation is contained within mica minerals within the granite rock.
In 2018 and 2019 Cornish Lithium began onsite surface exploration at its flagship hard rock lithium project at Trelavour Downs near St Dennis. Project identification was achieved through extensive research into exclusive historical resources, combined with the use of modern geological, geochemical, and geophysical datasets. This work identified Trelavour Downs and china clay pit as a top site for exploration and development, combined with the knowledge that Trelavour Downs was the only known site in Cornwall to have produced economic lithium during the second world war. Work ensued thereafter on collecting surface samples and conducting initial successful laboratory metallurgical trials.
In early 2020, Cornish Lithium conducted a highly successful first drilling programme at Trelavour. This comprised 40 drillholes for a total of 1,600m, using an open-hole percussive method and a highly reputable local drilling contractor. The drill programme gave Cornish Lithium the confidence that Lithium grades were indeed present at depth and allowed the team to define a very broad extent to which to focus further drilling on. Cornish Lithium’s geologists used the highest standards throughout the programme to ensure the best possible sample integrity, including a very vigorous QA/QC procedure. The high quality of data ensured that Cornish Lithium could use the drilling information to understand the geology in better detail to define controls on lithium grade across the deposit.
Throughout 2019 and 2020 Cornish Lithium developed a first draft of a mineral processing flowsheet to enable the concentration of lithium bearing micas. The simple but highly effective flowsheet allowed Cornish Lithium to successfully conduct a full lab-scale trial of conversion and production of battery grade lithium hydroxide. This was achieved using a proven method that has a low carbon impact but is highly effective.
Cornish Lithium plans to accelerate work to prove up the viability of the Trelavour project. This includes drilling of an extensive 3,400m resource definition programme in 2021. This will enable Cornish Lithium to produce a maiden JORC compliant resource with consultants and competent persons – Mining Plus. In addition to this, further drilling is planned for later in the year to extend the known footprint of lithium-enriched granite at Trelavour. Cornish Lithium will also be expanding on the successful metallurgical testwork developed so far, by building its first mineral processing pilot plant to treat 20 tonnes of granite and produce a lithium mica concentrate and furthering work on producing battery grade lithium hydroxide at a larger scale. Cornish Lithium is also advancing all aspects of the project to better understand what a successful mining operation will look like, it is doing this in tandem with local and specialist mining and processing consultants.