The Lac Guéret open-pit graphite mine located in north-eastern Québec, Canada, is being developed by Mason Graphite, which acquired the property from Cliffs Natural Resources in 2012.
The mine is expected to produce 50,000t of saleable graphite concentrate a year, at a recovery rate of more than 96%, over its estimated operational life of 22 years.
Construction of the graphite project is expected to start in 2015. The mine is expected to generate 80 direct jobs during its operational phase.
Lac Guéret graphite mine geology and reserves
Located approximately 300km north of Baie-Comeau in Côte-Nord region of Québec, the Lac Guéret property consists of 215 claims spread across 11,630ha (116km²).
The regional geology of the project area features Gagnon Group metasediments, including the traditional iron formation stratigraphy of the Wabush-Mont-Reed iron district. The graphite beds of Lac Guéret form part of the sediment of the Lac Guéret Member of the Menihek Formation.
Graphite at Lac Guéret is present in the form of fine to coarse crystal flakes in quartz and quartzofeldspathic gneiss and schist. The mining property comprises two graphite zones, namely the GC and GR zones. Graphite mineralisation at GC zone occurs over a strike length of up to 1.2km and is 400m-wide, and remains open to the north-east, north-west and at depth. Graphite mineralisation in GR zone extends for up to 1km and is around 110m-wide.
As of 17 January 2014, the mine was estimated to contain approximately 50 million tonnes (Mt) of measured and indicated resources grading 15.6% carbon as graphite (Cgr).
Mining and processing of ore from Lac Guéret
The conventional drill and blast method, followed by loading and hauling, will be used at the Lac Guéret open pit.
The run-of-mine ore will be conveyed to the feed hopper by trucks. The hopper will comprise a rock breaker for splitting the oversize boulders, while a vibrating grizzly feeder will feed the jaw crusher. The crushed material will be discharged into the semi-autogenous grinding (SAG) mill feed bin conveyor, before being delivered to the SAG mill for grinding.
Lac Guéret’s SAG mill will operate in a closed circuit with a screen, and the mill discharge will be pumped to a vibrating screen. Oversize ore material will be re-ground in the ball mill, while undersize material will be pumped to the coarse flotation circuit. The concentrate from the flotation circuit will then be pumped to the primary cleaner circuit, with the tailings pumped to the secondary grinding circuit.
Concentrate from the floatation circuits will be dewatered, thickened, filtered and dried before being packed for shipping.
Infrastructure facilities at the Québec graphite mine
The Lac Guéret mine is accessible from the paved all-weather road 389 from Baie-Comeau. Power supply for the mining operations will be provided by five on-site diesel generators.
The tailings storage facility will be located approximately 3.5km from the processing plant. Approximately 2.8Mt of tailings are estimated to be pumped to the facility during the mine life.
Contractors involved with Lac Guéret
Met-Chem Canada prepared the preliminary economic assessment report for the graphite mine, with support from SGS Minerals Services.
Roche Consulting Group prepared the mineral resources update for the deposit. Foramex was awarded the drilling contract for the graphite mine in October 2013.