Production is slated for August, 1988, at Les Mines Casa Berardi, the name given to the first new gold mine in this camp, which opened up only seven years ago. That’s when Inco and Golden Knight discovered the Golden Pond deposit, which in April of last year became the basis of the production decision. Located 50 miles north of La Sarre, Que., the deposit contains reserves of 10 million tons grading 0.2 oz gold per ton.
The Casa-Berardi area is within the northern part of the Abitibi Greenstone belt and is part of a major east-trending volcanic-sedimentary sequence that extends from Ontario through Matagami towards Chibougamau.
Inco’s director of exploration, R. J. Worsfold, says gold mineralization occurs over a strike length of 5 km within a steeply dipping 1-2 km-thick assemblage of dominantly sedimentary rocks lying between two regionally extensive iron formation units. Within this assemblage, mineralization is specifically associated with units consisting of mixtures of volcanic flows, pyroclastics and epiclastic and chemical sediments. A major east-striking graphic fault zone, the Casa Berardi Fault, is also spatially associated with the gold mineralization.
Economic gold mineralization occurs as massive quartz-carbonate vein complexes up to 10 m thick and as zones of quartz-carbonate vein stockworks, silicification and sericite- carbonate wallrock alteration, Worsfold says. Gold is present as fine free gold in quartz veins or in intimate association with disseminated pyrite and arsenopyrite in the zones of silicification and wallrock alteration.
Gold mineralization is controlled by ductile deformation associated directly with the Casa Berardi Fault. The mineralizaation is concentrated in sets of splay shears adjacent to the fault and at contacts between rock units of differing competency.
The joint-venture partners have agreed to build a $75.3-million mine, designed to treat 880 tons of ore per day.
MacIsaac Mining & Tunnelling is the major contractor on site, driving some 300 m of underground development headings. Cut-and-fill methods will be used, with mobile mine machinery gaining access to the stopes via a decline ramp. Casa Berardi Notebook Location: ……. 50 miles north of La Sarre, Que. Major owners: ……. Inco 60% and Golden Knight 40% Discovery date: ……. Golden Pond, June 1981; Golden Pond East, 1984 Production decision: ……. April, 1987 Start-up: ……. August, 1988 Capital costs: ……. $75.3 million (including working capital) Reserves: ……. 10 million tons, 0.22 oz gold per ton Means of access: ……. ramp Mining method: ……. cut-and-fill Production rate: ……. 880 tons per day Major contractor: ……. MacIsaac Mining & Tunnelling Status: ……. pre-production
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