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Eagle Graphite Incorporated (TSXV:EGA) has released pilot-scale results related to pre-concentration of feed material at the Black Crystal graphite project, located in northern British Columbia.
Eagle Graphite Incorporated (TSXV:EGA) has released pilot-scale results related to pre-concentration of feed material at the Black Crystal graphite project, located in northern British Columbia.
As quoted in the press release:
The Company considers the details of the concentration methods to be proprietary, however the concentration methods tested do not require the full infrastructure of a flotation plant, and can therefore be deployed at or near the quarry site.Tests were performed on approximately 50kg of rock sampled during the Company’s 2015 plant exploration program. The material for the sample was intentionally selected for having a substantially lower starting grade than the historical average for plant feed. The sample was crushed to -35 mesh and sorted into size fractions. 5kg of each size fraction was then processed in the pilot scale concentrator to produce several samples of concentrate and tails. By varying the equipment settings between samples, a range of single stage results was obtained for each size fraction.
Test results are summarized below: ---------------------------------------------------------------------------- Size % % of Concentrate Tails Fraction Total Total Starting Grade Grade Recovery (mesh) Mass Graphite Grade(1) Range Range(2) Range(3) ---------------------------------------------------------------------------- 35x25 24% 30% 1.6% 6%-95% 0.3%-0.9% 20%-85% ---------------------------------------------------------------------------- 50x35 31% 38% 1.6% 7%-88% 0.2%-1.1% 30%-80% ---------------------------------------------------------------------------- 80x50 22% 23% 1.4% 14%-84% 0.4%-1.4%(4) 43%-82% ---------------------------------------------------------------------------- 100x80 9% 4% 0.6% 1.2%-6% 0.4%-0.9% 14%-71% ---------------------------------------------------------------------------- -100 14% 5% 0.4% Not tested Not tested Not tested ---------------------------------------------------------------------------- Total 100% 100% 1.3%(5) ---------------------------------------------------------------------------- (1) All grades indicated are measured as percent graphite by mass. The weighted average starting grade for the entire sample was 1.3% (2) Tails grades between size fractions varied in part due to differences in starting grades between size fractions. Highest tails grades were associated with the highest concentrate grades. (3) Recovery is estimated as total mass of graphite in concentrate as a proportion of total mass of graphite in starting sample. (4) Unavoidable variability in random sampling occasionally yields a grade estimate that is outside expected bounds. (5) The 1.3% average grade of the sampled rock is substantially lower than the historical average plant feed grade of 3.9%.Based on these encouraging results, the Company intends to expand the investigation to include a wider variety of feed samples, multi-stage concentration circuits, and larger scale versions of the machinery used in the pilot tests. The Company wishes to emphasize that there is no guarantee that these investigations will result in any material operational improvements relative to historical practices.
Eagle Graphite President and CEO Jamie Deith stated:
Historically graphitic feed material has been transported from our quarry to the plant without much processing other than screening the occasional large rock out of the sandy host material. For some time, we have been looking at alternatives for concentrating the graphite at an earlier stage in the process. The objective is to separate out waste at the quarrying stage, and deliver a substantially higher grade of feed to the plant. The results so far are encouraging enough that we feel compelled to pursue this further.
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