Mattagarpi Lake Mines Ltd. Some Aspects of tbe Geology anti Ore Control

CIM Bulletin, 1964

R. H. Hallam At time of writing- Chief Mines Geologist, Mattagami Lake Mines Limited, Mattagami, Que.

The Mattagami mining district encompasses a favour able belt of folded Keewatin-type rocks, with intercalated sediments and intrusives of late Keewatin age. This environment has been subjected to periods of basic and acidic intrusion. The orebodies lie within the fold structure and are associated with faulting and shearing of considerable magnitude. The No. 1 orebody contains 60 to 70 per cent massive sulphides. The minerals, in their order of abundance, are generally: pyrite, sphalerite, pyrrhotite, magnetite and chalcopyrite. It is evident that the broad geological structure of the district is amenable to ore deposition. There are two prominent linear expressions which comprise this broad structure. Both strike directions lie at the edge of, or are related to, a complex gabbro-anorthosite-peridotite zone. The fact that eleven of the ore zones discovered to date coincide with the broad structure indicates its overall importance. It is estimated that the production from Mattagami Lake Mines will be in the range of 600 to 700 tons of zinc concentrate and 70 tons of copper concentrate per day.
Keywords: chalcopyrite, gabbro, Porphyry Peridotite Sill, rhyolite, sphalerite, Mine, Mines, Ore, Orebody, Ores, Rock, Rocks, Structure