Black Rock Mining has delivered what it believes to be world first pilot plant production of more than 99 per cent graphite concentrate using flotation methods.
The test was conducted as part of an upgrade program during recent pilot plant testing at SGS Lakefield in Canada for its Mahenge graphite project in Tanzania.
Black Rock produced an average grade of 99.3 per cent TGC (graphite) using the double loss of ignition method.
The industry-leading large flake product was produced after taking it to 99 per cent, according to Black Rock, demonstrating the mechanical strength of the Mahenge flake.
Black Rock chief executive John de Vries said the company was not aware of any deposit capable of producing 99.3 per cent 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,” de Vries said.
“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 per cent TGC.”
Black Rock also reported that 55 per cent of the ultra-high concentrate remained in the large/jumbo size fraction with minimal degradation in the upgrade circuit.
“With over 55 per cent of the ultra-grade concentrate reporting to the large and jumbo fraction, this simply underlines how remarkable Mahenge flake really is,” de Vries added.
Black Rock has started shipping of the ultra-high concentrate to potential global customers and partners.