Junior graphite producer Black Rock Mining (ASX: BKT) thinks it can deliver 99% pure graphite at scale, following successful test results conducted on ore from its Mahenge graphite project in Tanzania.
Using only floatation methods, Black Rock managed to produce 99%-plus graphite concentrate during recent pilot plant testing at SGS Lakefield in Canada. The pilot plant trial run generated 200kg of graphite concentrate which was then reprocessed through a polishing circuit to create the ultra-high grades.
SGS Lakefield completed the pilot plant test work, processing 90 tonnes of Mahenge ore, comprising 50t from Cascades and 40t from Ulanzi – two of Black Rock’s most highly prized prospects according to recently published exploration data.
The highest carbon grade was 99.8%, while the lowest was 99% from eight separate test scores with varying mesh size ranging from -200 to 32.
“We are not aware of any deposit that is capable of producing 99.3% grade concentrate by standard flotation alone. Being able to generate ultra high-grade product using flotation is of significant value to downstream processors who are increasingly finding environmental constraints impacting their business,” said John de Vries, chief executive officer of Black Rock.
Mr de Vries also said that Black Rock’s results are superior to those announced by larger graphite competitor Syrah Resources, following its own recent announcement planning to increase graphite grades at its Balama project up to around 97-98% purity.
Competition for Tanzanian graphite
Black Rock is currently vying to establish an economically viable graphite production business with other larger peers such as Syrah, Magnis and Kibaran also in the mix.
Black Rock’s 100%-owned Mahenge graphite project is one of the largest JORC-compliant flake graphite resources globally, sporting a mineral resource estimate of 211.9 million tonnes at 7.8% total graphitic carbon for 16.6mt of contained graphite.
One potentially key caveat that’s working in its favour is more than 50% of the resource is in the measured and indicated categories which suggests a strong confidence level that Black Rock will be able to commercialise its multimillion tonne endowment.
“We are particularly pleased with the minimal flake degradation during the additional polishing. With over 55% of the ultra grade concentrate reporting to the large and jumbo fraction, this simply underlines how remarkable Mahenge flake really is,” said Mr de Vries.
“We believe through the consistent delivery of outstanding results and steadily progressing the project, Mahenge is demonstrating itself as the best undeveloped graphite project available globally,” he added.