Deep-drilling polymetallic find Victor a major new discovery for

Crowning 16 years of exploration by Inco (TSE) in the Victor area on the eastern rim of the Sudbury, Ont., basin, three deep drill holes have returned assays that are little short of momentous.

Grades of 1.5-2.6% nickel, 5.1-7.4% copper and 0.2-0.5 oz. per ton of the precious metals platinum, palladium and gold have been intersected across widths ranging from 198.5 ft. to 253.4 ft. Drill hole depths are 8,000-8,800 ft. below surface.

To put this into context, the average grade of ore milled by Inco in 1991 was 1.1% nickel and 1% copper; even in the palmy days of 1985, the grades were little more than 1.3% and 1.2%, respectively.

Victor is about 6.5 miles north of the town of Falconbridge. The onetime small producer, Nickel Rim, is about half a mile to the east. Earlier exploration at Victor in 1975 located a 7-million-ton deposit about one half-mile to the south of the new discovery at a depth of 5,500 ft. The new discovery indicates a minimum 4.6 million tons and taken together with other drill results plus a general interpretation of the local geology, Inco infers the presence of 20-40 million tons of mineralization. With the drilling of a given hole plus its wedged branches taking 4-6 months to complete, and costs from $750,000 to $1 million a crack, diamond drilling has achieved its purpose. (Heath and Sherwood of Kirkland Lake, Ont., is the drilling contractor.)

A major find has been made and the next phase is to sink a shaft and probe the mineralization from underground.

Drilling will be concluded in early 1992 and it had been hoped that an exploration shaft could be started the same year, said Alan Sauerbrei, director of exploration, eastern North America. The shaft would bottom at about 8,500 ft. With Inco’s recently announced cutbacks, this is now questionable.

At 8,000-9,000-ft. depths, temperatures can be expected to be high and Inco’s Creighton shaft, the deepest in the area, reaches to 7,137 ft. Virgin rock temperatures are 42 degrees C at 7,000 ft. and consequently the Victor shaft will need refrigeration, at least in the early stages.

Shafts elsewhere drop to 10,000-12,000 ft. and mining is within the reach of present-day technology at these depths.

A second new find has been made by Inco, this time midway between the Levack and McCreedy East mines. Preliminary reserves are estimated at 4.6 million tons grading 0.80% nickel, 11% copper and 0.3 oz. precious metals. This mineralization occurs at 3,500-5,000 ft. below surface. It is open along strike and downdip, and in conjunction with other data, Inco infers the presence of eight million tons of mineralization.

The Victor find owes much to the re-interpretation of Sudbury geology; Sauerbrei credits down-the-hole geophysics for much of the company’s success both there and at McCreedy. In earlier years, drill holes were stopped at the ore making intrusive contact. During the past 15-20 years, major tonnages of ore have been located up to half a mile away from the contact and a major effort was made to determine if this characteristic held true on the eastern rim. Victor appears to have proved the case.