Black Rock Mining has successfully produced graphite concentrate with a purity of more than 99% as part of its pilot plant testing programme at SGS Lakefield in Canada.
The tests were conducted on ore from the company’s Mahenge graphite project in Tanzania using only floatation methods.
Black Rock generated 200kg of graphite concentrate during the trial run, which was then reprocessed using a polishing circuit to produce ultra-high grades.
An average grade of 99.3% total graphite content (TGC) was produced using a double loss on ignition (LOI) method.
The company claims the latest tests have resulted in the world’s first production of more than 99% pure graphite concentrate.
Black Rock Mining CEO John de Vries said: “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.
“The value proposition of producing high-specification concentrate has been validated by Syrah Resources’ recent announcement of planned increases of Balama concentrate grades to a targeted 97%-98% TGC.
“With over 55% of the ultra-grade concentrate reporting to the large and jumbo fraction, this simply underlines how remarkable Mahenge flake really is.”
The company processed a total of 90t of Mahenge ore as part of the trial initiative, comprising 50t from Cascades and 40t from Ulanzi.
The Mahenge project is estimated to have mineral resources of 211.9 million tonnes (Mt) at 7.8% TGC for 16.6Mt of contained graphite.