Castle Minerals has revealed a bulky 38 per cent boost to the mineral resource estimate at its Kambale graphite project in Ghana, taking it to 22.4 million tonnes averaging 8.6 per cent total graphitic carbon (TGC).
Importantly, the company says 43 per cent of its newly-tabled estimate falls within the higher-confidence indicated resource category that is now tipping the scales at 9.6 million tonnes at 8.8 per cent TGC.
The updated resource estimate comes hot on the tail of a spate of impressive results from 43 reverse-circulation (RC) drillholes Castle plunged into its deposit in August that included 86m going 8.2 per cent TGC from 104m, with grades peaking at 24.1 per cent TGC.
Management says the drilling helped etch out additional mineralisation that had been excluded from its maiden mineral resource estimate, extending the mineralised envelope almost 200m north along strike and providing greater confidence in the geological model.
Graphite mineralisation at Kambale has been delineated in a 2.3km north-south corridor that extends up to 500m wide and down to depths of at least 150m below surface by several phases of trenching and a combined 424 holes for 21,569m of rotary air blast (RAB), air-core (AC), RC and diamond-core drilling campaigns.
The Kambale graphite deposit sits within a broader 149-square-kilometre licence area within Ghana’s mining-friendly Wa region and close to major sealed roads and rail networks.
The company says historical mapping and ground electromagnetic (EM) surveys have highlighted several priority targets within its tenure that are worthy of investigation. Interestingly, previous ground EM surveys successfully generated multiple below-surface conductors where subsequent RC drilling has intercepted graphite mineralisation.
Recent metallurgical testwork completed on a 215kg composited raw, unweathered diamond-core sample from Kambale shows that production of commercial-standard specification grade for bulk fine-flake graphite concentrate grading 95.1 per cent TGC is possible using conventional grinding and flotation methods.
The graphite concentrate has since been transported to specialists ProGraphite GmbH in Germany for micronisation, spheronisation, purification and coating tests to replicate the usual commercial processing stages before being subject to a series of electrochemical and battery performance tests to determine its suitability for the manufacture of battery anode material (BAM).
With a fresh set of resource figures, coupled with the results of recent metallurgical test work, management says a scoping study is set to begin to consider the technical and commercial merits of a mining and processing operation in Kambale.
The MRE increase provides a very solid platform upon which to advance our development ambitions, especially now that Castle has demonstrated in testwork that a fine flake graphite concentrate of commercial specifications can be produced using conventional flotation process. This is the primary material used in the manufacture of lithium-ion battery anodes. Castle Minerals managing director Steve Stone
The updated estimate comes as China, the world’s biggest producer of graphite, announced restrictions late last week on graphite exports to protect national security and its own electric vehicle (EV) industry.
According to Chinese customs data, Japan, the United States, India and South Korea are the country’s top graphite buyers and the latest announcement prompted a mad dash by automaker giants Tesla and Mercedes to lock in graphite supply from non-Chinese suppliers.
Graphite is the largest EV battery component by weight, with each vehicle on average using 30kg to 60kg of battery-grade graphite – about double the amount of lithium in an EV battery.
According to the US Geological Survey, the battery end market for graphite has soared by 250 per cent globally since 2018.
So, it seems it is a moment of serendipitous timing that Castle has strung together a hefty boost to its Kambale graphite mineral resource estimate, just as the world’s leading car makers cast their gaze further afield from China’s geopolitical mine-field to shore up supplies of the critical mineral.
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