The Delta Southwest occurrence is located within a narrow band of felsic pyroclastic rock of the Mount Dilworth Formation, Hazelton Group. This unit conformably overlies the Betty Creek Formation and may para- conformably underlie the Salmon River Formation which occurs to the immediate east of the mineralized zone. The mineralization occurs in an area of intense quartz-pyrite-carbonate-sericite alteration (Open File 1988-4; Fieldwork 1987).

The area is comprised of calcareous rhyolite tuffs with flat to shallow dips into the hill. Underlying rocks consist of carbonaceous argillites with some limey sections. A steep dipping 150 degree trending cross fault cuts these rocks. A small body of Eocene age feldspar porphyry intrudes just east of the area of interest.

A number of mineralized "minor steep dragfold nose dilations" and tension faults contain pyrite and tetrahedrite respectively. In one location visible gold was observed with the tetrahedrite. The tension faults appear to feather off of the main fault.

One sample from a large gossanous outcrop containing massive pyrite assayed 2.06 grams per tonne gold, 10.63 grams per tonne silver, 0.01 per cent copper, 0.11 per cent lead, 0.02 per cent zinc and 0.05 per cent stibnite. The highest silver value obtained was 46.29 grams per tonne (Assessment Report 14607).

Five diamond-drill holes were collared in this area in 1986 with a total of 300 metres drilled. The highest value obtained was 0.375 gram per tonne gold; no anomalous silver was found (Assessment Report 15645).

See Delta (104B 166) for further details of the Delta property and work history.