The Northface (Sue-KEI) occurrence is exposed in a large cliff face on the south of Petrie Creek and approximately 7.8 kilometres north of the southeast end of Redfern Lake.

The northern portion of the Redfern Lake area is underlain by a conformable package of Cambrian to Ordovician Kechika Group, Middle Ordovician Skoki Formation, an unnamed Upper Ordovician unit, Silurian Nonda Formation, Lower Devonian Muncho-McConnell Formation, Lower to Middle Devonian Stone Formation and Middle Devonian Dunedin Formation strata. To the east, this package is thrust over Dunedin and Stone Formations. These are in turn thrust over Devonian and Carboniferous Besa River Formation shale. The Dunedin Formation can be divided into a lower dolomite unit and an upper micritic limestone unit.

The Northface (Sue-KEI) occurrence occurs at two stratigraphic levels within the Dunedin Formation carbonates. The lower zone occurs as fine disseminated sphalerite, smithsonite, and pyrite in brecciated argillaceous dolomite. The breccia is healed by coarse crystalline white dolomite and calcite. This zone can be traced for 60 metres and is 7 metres thick.

The upper zone is hosted in clean, massive, shattered and brecciated limestone. The mineralization, traced for over 200 metres with a width of 6.4 metres, consists of disseminated pyrite, sphalerite and galena associated with calcite, dolomite, and quartz crystals. Pyrobitumen is common in patches and as fine flecks in coarse crystalline patches.

In 1973, samples (KEI-S-2a and KEI-S-3b) from the first and second ledges assayed 2.5 and 0.85 per cent lead with 16.5 and 4.2 per cent zinc per cent zinc, respectively, whereas other samples yielded up to 8.0 per cent lead and 20.5 per cent zinc (Sample KEI-S-1b; Assessment Report 4722).

In 1974, 90 grab samples from a mix of boulders and outcrops on the Sue occurrence area yielded an average of 6.4 per cent zinc and 1.0 per cent lead (Assessment Report 5316). Other mineralized float samples were identified over an area encompassing approximately 900 by 600 metres and yielded values of up to 16.5 per cent lead and zinc combined (Assessment Report 5316).

In 1975, assays from the lower zone returned less than 2 per cent zinc, whereas the best assay from the upper zone yielded 5.0 per cent zinc and 0.09 per cent lead (Sample 75C-21; Assessment Report 5551).

In 1976, diamond drilling indicated that the mineralization appeared to be concentrated at the base of the breccia zone and is strongly associated with one layer of dark microcrystalline dolomite with Amphipora replaced by sphalerite then calcite at their centre. The best drilling intercept yielded 6 per cent zinc over 3.3 metres (21.0 to 24.3 metres down hole) in hole RW-1, whereas other drillholes yielded from 3.7 per cent zinc over 1.35 metres to 1.5 per cent zinc over 0.45 metre from the same layer (Assessment Report 6208).

Another minor zone of mineralization, referred to as the KEI-4 zone, is located on a roughly north-south–trending ridge approximately 2.2 kilometres north of the Northface occurrence and comprises a calcitic zone in a limestone hosting chalcocite with malachite staining.

Work History

In 1972, Vestor Explorations Ltd. completed a program of geological mapping and soil sampling on the area immediately south of the occurrence as the Chilly, Damn, Egg and Foo claim groups. The following year, Rio Tinto Exploration Canada Inc. completed a program of geological mapping, minor rock sampling, a 36.2 line-kilometre induced polarization survey, a 30.5 line-kilometre ground magnetic survey and a photogeological study on the Foo, Egg, Chilly, Vista and Damn claim groups. In 1974, Rio Tinto Canadian Exploration Ltd. completed nine diamond drill holes, totalling 608.0 metres, on the Vestor property. The following year, a further program of geological mapping and soil sampling was completed on the property. In 1979, Teck Explorations Ltd. completed a program of geological mapping and geochemical (rock and soil) sampling on the Vestor property.

Also, during 1973 through 1975, Aquitaine Company of Canada Ltd. completed programs of prospecting, geological mapping, geochemical (rock, silt and soil) sampling, a photogeological study and a 5.0 line-kilometre induced polarization survey on the area as the KEI claims. This work originally identified the occurrence. In 1976, Aquitaine completed five diamond drill holes, totalling 575.0 metres, on the KEI claims.