QUEBEC – Focus Graphite of Ottawa is designing the flowsheet for a mill at its Lac Knife high grade graphite project near Fermont. To gain important technical knowledge, a mineralized sample was run through a pilot plant.
The graphite concentrate generated from the pilot flotation plant had an average grade of 98.3% total carbon (Ct) in the +80 mesh fraction. That is better than the 97.4% Ct recording during phase two locked cycle tests. In the medium size fraction (-80 mesh, + 150 mesh) the grade was 98.2% Ct compared to 97.4% in earlier tests. The average grade of the fraction +200 mesh was 98.0% Ct, again up from the 97.2% Ct in the phase two tests.
Focus noted that concentrates of all three size fractions responded well and cost effectively to flotation. The high concentrate grades will reduce the level of impurities that have to be removed by thermal or hydrometallurgical purification.
The pilot plant testing was done by SGS on a 23.3 tonne composite of drill core samples collected from the massive, semi-massive and low grade mineralization zones of the Lac Knife graphite deposit. The average head grade of the sample was lower than the deposit average grade at 11.8% Ct in order to be able to increase the amount of mineralized material available for pilot plant testing at that time. Even with the lower head grade the metallurgical results were excellent confirming the robustness of the concentrator flowsheet design, said the company.
The Lac Knife property has an indicated resource of 4.9 million tonnes grading 15.8% graphitic carbon (Cgr) as crystalline graphite. There are also 3.0 million inferred tonnes at 15.6% Cgr.
Learn more by visiting FocusGraphite.com.