A BREAKNECK PACE Isle Dieu

The official opening of Noranda Minerals Inc.’s Isle Dieu mine, near Matagami, Que, is scheduled for September. Discovered in May, 1985, the rich zinc deposit, grading 17.78% zinc, 1.03% copper, 2.344 oz silver and 0.013 oz gold per ton, has mineable reserves sufficient for about six years of mining. Grades are so high that the new mine will produce only half as much ore per day as the Matagami Lake mine, located a mile to the southeast, but combined total production of concentrates will double. The lower- grade Matagami Lake mine is scheduled to run out of ore this year. Ore from Isle Dieu will be processed in the Matagami mill, so capital costs will be only $35 million for the underground mine.

J.S. Redpath was responsible for mine development. A 3-compartment shaft to a depth of 2,125 ft provides access. Mining will include both open stoping, using bbc 120 long hole drills, and mechanized cut-and-fill stopes to produce 20,000 tons of ore per month from August, 1988, to November, 1988. Production is then scheduled to increase to 25,000 tons a month until February, 1989, and 30,000 tons per month after March, 1989. Noranda expects dilution will be 15% while 90% of the blasted ore will probably be recovered from the stopes.

The orebody is in the shape of a plane 900 ft by 1,200 ft that is elongated in an east-west direction and dips 45 degrees to the southwest. Thickness varies from 2 ft to 132 ft. The sulphide zone is split in a near-horizontal fashion by a thick tonalite dike. The upper section of the massive sulphide zone consists of massive sphalerite with some pyrite, chalcopyrite and minor galena. The zone occurs at the 1,370-ft level.

The sulphide zone below the dike, on the 1,550-ft level, consists of sphalerite, pyrite, chalcopyrite, magnetite and chert. The thickest sulphide sections occur along the northern margin of the deposit where the total thickness may exceed 100 ft. The thickness of the zone decreases rapidly southwards and sulphides are incorporated within the tuffite.

Beneath the sulphide zone, the Key Tuffite is strongly brecciated and cut by numerous stringers of sphalerite, chalcopyrite and pyrite. The “feeder” or “stringer zone” underlying the former consists of a strongly chloritized and brecciated rhyolite. Isle-Dieu Notebook Location: ……. Matagami, Que Major owner: ……. Noranda Minerals Inc. (100%) Commodities: ……. zinc, copper, silver, gold Discovery date: ……. May, 1985 Production decision: ……. June, 1986 Start-up: ……. September, 1988 Capital costs: ……. $35 million (budgeted) Reserves: ……. 2,064,200 tons — 17.78% zinc, 1.03% copper, 2.344 oz silver and 0.013 oz gold per ton. Mining equipment: ……. one ST-2 load-haul-dump, scissor lifts, pneumatic 3-boom jumbo, one 4 1/2 -in diameter in-the-hole drill, one BBC 120 long hole drill, electric and diesel ST-5 scoops, and one electric-hydraulic hammer. Mining method: ……. open stoping (long hole) and mechanized cut-and-fill Production rate: ……. 30,000 tons per month by March, 1989 Milling: ……. Use existing Matagami Lake mill Major contractor: ……. J.S. Redpath Ltd. Status: ……. pre-production