Northfield drilling to expand Cheminis reserves

In a quest to augment and upgrade gold reserves, Northfield Minerals (TSE) has embarked on a major program at its Cheminis mine near Larder Lake, Ont.

The program, estimated to cost more than $1 million, will include surface and underground drilling, as well as underground development work. Having been worked sporadically since its discovery in the 1920s, the Cheminis deposit was finally brought into production by Northfield in 1993, following several years of exploration and development.

Mining has been confined to the C zone, where reserves are estimated at 170,000 tons grading 0.17 oz. However, additional, drill-indicated reserves of 1.8 million tons grading 0.168 oz. are present in the A, B, D, E and North Carbonate zones.

Two types of ore are present: flow and green carbonate. The latter is hosted in an altered, ultramafic unit, and mineralization consists of erratic, free gold in quartz veins. Flow ore, on the other hand, is contained in a graphitic tuff horizon that stratigraphically overlies the green carbonate zone to the south. Gold in the flow ore is associated with pyrite. The property lies along the same horizon that hosts the Kerr mine, situated 4 miles to the east. Kerr, which is being operated by Deak Resources (TSE), has produced more than 11 million oz. gold.

The flow zone at Kerr has accounted for roughly 60% of its ore; and, to date, only flow ore has been exploited at Cheminis.

To prove up additional reserves at Cheminis, underground drilling will be carried out on the 525, 695, 865, and 1035 levels. To establish grade, bulk sampling is planned for the 275, 695, and 865 levels.

The surface program, which consists of four deep holes, is targeting the D zone, which was discovered by Kerr-Addison Mines (TSE) in 1978 when a deep hole (KAL78-1) intersected 0.20 oz. over 22.2 ft. at a vertical depth of 2,200 ft. The D zone is an area of typical flow ore, which extends below the 1035 level.

Northfield Chairman Dale Hendrick says the deep program is designed to prove up additional reserves in the D zone and test other horizons at depth. Hole 84-5, drilled in 1984, cut 0.05 oz. over 27.5 ft. in the D zone and crossed into a green carbonate zone where it yielded an 8.9-ft. section grading 0.24 oz. per ton. This hole also intersected a second, subparallel flow ore horizon, about 200 ft. north of the D zone.

The four surface holes will be wedged from Hole 84-5, beginning at a depth of about 1,600 ft.

A hole now being drilled is aimed at drilling through the D zone and into the carbonate zone, about 400 ft. deeper than Hole 84-5.

Initial results from both the underground and surface programs are expected in about a month.

Cheminis is producing about 6,000 tons of ore per month, which is being custom-milled at American Barrick Resources’ (TSE) Holt-McDermott operation, 25 miles to the north.