Noranda OKs production on rich Isle Dieu orebody

What is so far a small but very rich zinc-silver-copper deposit near Matagami in northwestern Quebec is being put into production by Noranda Minerals at a cost of $35 million.

Site preparation on the Isle Dieu Mattagami Mines property has started and a 2,200-ft, 3-compartment shaft has already been collared by J.S. Redpath. Shaft sinking is scheduled to begin before the end of the year.

The main ore zone has been tested to 2,200 ft and preliminary geological reserves, before dilution, are estimated at 2.3 million tons of indicated and probable ore. The grade is set at 22.4% zinc, 1.23% copper and 2.77 oz silver per ton. Another 303,000 tons have been classed as possible ore with similar grade and drilling is continuing with four rigs in an attempt to define the eastern limits of the deposit.

By comparison, the Winston Lake deposit in northwestern Ontario being developed by Falconbridge Ltd. has, on a diluted basis, about 3.4 million tons of probable and possible ore grading 16% zinc, 1.0% copper and 0.96 oz silver per ton.

“It’s virtually price insensitive,” says John Davies, senior vice- president of Noranda Sales, referring to the high grade of the Isle Dieu deposit and its proximity to the Noranda’s established Mattagami Lake mining operation.

In fact, the Isle Dieu deposit is expected to be in production by late 1988, shortly after the Mattagami Lake orebody is exhausted. The Isle Dieu property will supply about 850 tons of ore per day to be put through the Mattagami Lake mill about a mile southeast of the new deposit. At that rate current reserves are good for about seven years.

The existing mill can handle about 3,700 tons per day and is currently running at less than capacity although it is handling about 1,500 tons per day from Mattagami Lake as well as ore from Noranda’s nearby Norita deposit and Abcourt Mines’ zinc mine.

Mr Davies says Isle Dieu could supply about half the ore that Mattagami Lake currently supplies and still produce twice the concentrates because of the high grades. Zinc grade of the Mattagami Lake ore currently runs at about 5-6%.

The two deposits are very close. Isle Dieu is about 6,000 ft from the Mattagami Lake mine shaft.

Mr Davies says at current price levels the Mattagami Lake orebody will provide ore for 1987 but “it’s 1988 that’s going to be difficult.” If zinc prices improve, Mattagami Lake could provide more ore of a lower grade before the deposit is depleted.

The Isle Dieu discovery has given new life to the community of Matagami. Noranda is the town’s major employer with more than 400 people at its Mattagami Lake mining operation

The Norita orebody, like the Mattagami Lake orebody, is also on the decline says Mr Davies. However, Noranda is exploring that area, too.