Apr 20 2017
Northern Graphite Corporation ("Northern" or the "Company") is pleased to announce the results of additional metallurgical test work designed to optimize the purity of concentrates that will be produced from the Bissett Creek deposit.
Testing was carried out by SGS Lakefield ("SGS") and evaluated new approaches to graphite processing that have been developed since the Company completed its Full Feasibility Study.
SGS evaluated the effect on the flake size distribution and carbon content of graphite concentrates from using a stirred media mill instead of, or as a compliment to, the polishing mill. The stirred media mill successfully increased the overall purity of an earlier pilot plant concentrate from 93.4 to 97.9 per cent graphitic carbon ("Cg"). The increase was mainly attributable to the smaller size fractions which averaged over 97 per cent Cg. High purity levels of 97 to 98 per cent had already been confirmed in the important +32 mesh (XXL) and +50 mesh (XL) size fractions through locked cycle tests. Graphite concentrates are typically sold with 80% meeting the required size standard. Smaller sizes can make up the balance as long as the purity level is maintained which will be the case with Northern's concentrates.
Gregory Bowes, CEO commented that: "Bissett Creek concentrates are already high quality and the increased purity of the finer materials will further enhance their price and marketability. Only 10 per cent of the Company's production will be -150 mesh, which we believe is the lowest in the industry, and it can easily be absorbed into larger size concentrates. Almost every graphite mine has a fines problem as they must be sold into low growth, low value, competitive markets but this will not be an issue for Northern."
Purification
The amount and nature of impurities in graphite concentrates affects their value, marketability and ability to be upgraded for use in higher value applications. Ore from the Bissett Creek deposit fractures easily, releasing the flakes, which are generally not interleaved with impurities. As a result, Bissett Creek ore does not require fine grinding or multiple stages of polishing and cleaning to achieve required purity levels. These steps increase costs and reduce the yield of large flakes. Concentrates also do not have a high iron or carbonate content, which would make them unsuitable for the refractory market, or large quartz grains which would make them unsuitable for other markets and which creates challenges in upgrading them for high purity markets. Independent testing by NGS Naturgraphit GmbH did not detect any limitations on potential uses for Bissett Creek concentrates (see March 2, 2015 Press Release).
The largest and most important high purity market is spherical graphite ("SPG"), the anode material used in lithium ion batteries. The main impurity in the Northern's concentrates is biotite which can easily be removed using a cost competitive, environmentally sustainable, proprietary process. The Company is currently testing its process on SPG from a number of other deposits and intends to conduct a pilot plant test to confirm the ability to scale the process to higher volumes and to refine capital and operating costs.