There were only 10 present for last night's Cornish Mining Sundowner at Falmouth's Chain Locker, but there was interesting news of developments in Cornwall.
The South Crofty tin mine is scheduled to come back into production at the end of 2027 and last night it was good to talk to the COO of Cornish Metals, Owen Mihalop, and Mike Hallewell, Consulting Metallurgist, on the latest developments. Mike has been working on the proposed flowsheet, which is based on the original flowsheet used at Wheal Jane in the 1990s, but is adapted to incorporate modern separation technologies that were not available 30 years ago.
Pre-concentration is a key feature to reduce downstream processing and pastefill costs and incorporates the latest TOMRA XRT technology for the coarser fractions and Gekko jigs for the finer fractions. DMS is replaced by jigs due to the considerable cost savings. The Gekko jig metallurgy is currently being tested but is anticipated to provide Cornish Metals with a much more attractive option.
Spiral concentration is incorporated into the grinding circuit as it was at the old South Crofty, so that coarse cassiterite is recovered prior to ball milling and around 20% of the cassiterite is estimated to be recovered via this simple route.
Multi spigot hydrosizers and Holman Wilfley shaking tables will make up the majority of the downstream circuit as it did at Wheal Jane, but Mozley MGS technology will be used on the finer size fractions where shaking table efficiency is compromised.
The Wheal Jane deslime and tin float circuit will be replaced with much simpler, lower cost and easy to operate Falcon "continuous" units for roughing at high G force and MGSs for cleaning at a lower more discerning G force.
In the photo below I am with Dave Mildren, of Gravity Mining Ltd, the Cornish company who will supply the MGS machines, Owen Mihalop, Mike Hallewell and Dave Goldburn of Holman Wilfley.
It was good to hear this month that Cornish Lithium has been granted planning permission to build the UK’s first commercial lithium production facility in Cornwall, to be established at the Cross Lanes Lithium Project, near Chacewater. The facility, which will include a demonstration plant phase, will enable Cornish Lithium to implement multiple phases of testing and enhancements, with a long-term aim of achieving full commercial production at the site. I talked to Jonny Coad and Tim Richard, Process Operatives at Cornish Lithium, about developments.
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| Jonny and Tim |
Phase One of the project will involve drilling and testing two 2,000-metre-deep production-scale geothermal wells, which will build on successful exploration drilling at the site. Lithium-enriched geothermal waters will be extracted from the first well using state-of-the-art Direct Lithium Extraction (DLE) technology. Once the lithium has been extracted, the water will then be returned underground via the second well. These production-scale wells will also allow the Company to assess the potential for harnessing heat from the same geothermal waters to provide heating for local homes and businesses.
In Phase Two, a temporary demonstration plant will be constructed and operated to validate the production of lithium compounds at the Cross Lanes site. This phase will evaluate the opportunity to provide samples for battery and electric car manufacturers. Following successful testing and evaluation, Cornish Lithium intends to construct a commercial plant at this location.
Having drilled and tested an exploration borehole at Cross Lanes in 2023, Cornish Lithium has already established that lithium-enriched geothermal waters circulate naturally within the permeable geological structures that underlie the area. This, together with the progress made at its pilot plant facility at United Downs, where the Company has been evaluating numerous DLE technologies since 2021, affirms the feasibility of building a demonstration plant, and subject to further evaluation, a commercial-scale lithium processing facility at the Cross Lanes site. With planning consent now in place, work on the Cross Lanes Lithium Project is expected to begin this spring (see also posting of 18 September 2020).
Founded in 2016, Cornish Lithium now has 105 employees, many of then graduates from the Camborne School of Mines (CSM), including Chairman and CEO Jeremy Wrathall. In 2021 Camborne was placed world number 8 in the field of Minerals & Mining Engineering in the QS World University Rankings, its highest ranking ever. All the more ironic as two months earlier, following 5 months of deliberations, Exeter University decided to discontinue the Mining Engineering undergraduate degree programme.
The 2025 Rankings have now been published and not surprisingly Camborne's ranking has dropped to a still respectable #19, its great rival, the Royal School of Mines at Imperial College now in 8th position, and the "other CSM" the Colorado School of Mines in its usual top spot. It is to be expected that Camborne will climb up the ladder again in future years now that the mining degree has been reinstated, commencing again this October.
It was good to catch up with Ben Williamson, who was a lecturer at CSM for 15 years, but is now going solo, launching his own business in Bristol. GEOXPERT HUB is a new web platform designed to connect mining companies with expert consultants, streamline recruitment and to promote specialist services. The website will officially launch in the next few weeks. In preparation for this, he is offering promotional rates for small companies to grow their business.
Ben is left on the photo below, with 1967 CSM graduate Pete Shepherd (right) and in the centre a new face at the sundowners, Dave Cadwell of Gravity Mining.
An interesting evening with a smallish group of people. The next sundowner is on Thursday April 17th, from 5.30pm at the Chain Locker.
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