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Castle kicks off new year with major graphite milestone

Updated: 4 days ago

Castle Minerals has achieved 99.97 total graphitic carbon from testwork at its Kambale proCastle Minerals has achieved 99.97 total graphitic carbon from testwork at its Kambale project in Ghana. Credit: Fileject in Ghana. Credit: File

Castle Minerals has achieved purification levels of 99.97 per cent total graphitic carbon (TGC) from ore at its Kambale project in Ghana, exceeding the benchmark required to produce lithium-ion battery anodes.

The news quickly resonated with the ASX market as the company’s share price jumped 50 per cent during intraday trading today to touch 0.9c after closing at 0.6c on Friday. Management says the impressive purity has been confirmed by an independent laboratory with no impurities of concern noted.

The testwork was undertaken by Germany-based company ProGraphite on 10kg of bulk fine flake graphite concentrate grading 95.1 per cent TGC. The concentrate was produced from flotation test work on a composite sample of Kambale diamond core samples grading about 10 per cent TGC.

Management says purification of the spheronised material was achieved using a conventional alkaline, caustic soda-based process and did not require the application of hydrofluoric acid that can introduce major handling issues and other safety considerations.

Based on the latest testwork results, Castle says it has engaged a team of specialist mining, processing and study engineers and a market specialist to begin a high-level assessment of the technical and commercial merits of establishing a mining and processing operation at Kambale.

Once that is completed, the company believes it will be in a position to begin discussions with product offtakers and development and financing partners.

Meanwhile, ProGraphite is set to initiate a series of electrochemical and charge-cycle tests on the Kambale material to assess its charging and other performance characteristics. The work is expected to take several weeks to complete.

Prior to the successful purification process, concentrate from the project underwent various pre-treatments and analyses to obtain a comprehensive characterisation of the material. It was then micronised using an impact mill to generate a relatively uniform particle size range ahead of the spheronisation process, where the fine graphite flakes are moulded in a special mill into sphere-shaped masses. The company says the process increases carbon and packing density and maximises battery charge capacity.

With no impurities of concern this exceeds the stringent specification benchmark set by offtakers who manufacture lithium-ion battery anodes used in electric vehicle, stationary power storage units and consumer electronics. Kambale mineralisation is now confirmed as a bona-fide source of natural fine flake graphite, which is the exact form of graphite forecast to move into a substantial supply deficit as the rapid take up of EVs continues. Castle Minerals managing director Stephen Stone

In October last year, management unveiled a 38 per cent boost to the mineral resource estimate at the project, taking it to 22.4 million tonnes averaging 8.6 per cent total graphitic carbon (TGC).

The updated resource followed 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. 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.

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 latest testwork results come as China, the world’s biggest producer of graphite, announced restrictions late last year on graphite exports to protect national security and its own electric vehicle (EV) industry.

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.

According to the US Geological Survey, the battery end market for graphite has soared by 250 per cent globally since 2018.

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