The area of the Billican prospect is underlain by basalt and massive to locally bedded chert of the Permian to Jurassic Hozameen Complex. Basalt-chert contacts are steeply dipping and probably faulted. Small intrusions of diorite to granodiorite of unknown, but probable Tertiary age occur in the basalt. A fault striking 015 degrees along Pyrrhotite Creek truncates a 120 degree striking fault that passes through the Giant Creek area. Monger has mapped another west-northwest striking fault in the valley north of the property (GSC Map 12-1969).

Over several square kilometres, the basalt is altered and veined. Alteration consists mainly of silicification and lesser sericitization. Three main types of mineralization are reported to occur in the vicinity; these include skarn, veins and porphyry types.

In one cut, a 5 to 10 centimetres vein of massive, coarse- grained pyrrhotite with lesser sphalerite, and other similar smaller veins with quartz, are exposed. Some veins are traceable for several tens of metres. About 90 metres to the southeast, two skarns are exposed in cuts. Both skarns are apparently in the form of pods up to 5 metres across. They contain a variety of mineral assemblages and textures as follows:

1) massive pyrrhotite-quartz with lesser sphalerite

2) coarse-grained garnet enclosing fine-grained magnetite-

garnet-quartz

3) grossular garnet and calcite in replacement veinlets and

patches in basalt

4) garnet-epidote-actinolite with minor pyrrhotite

5) garnet-calcite-magnetite with patches of vuggy quartz.

A few tens of metres above this is a small skarn up to 2 metres across and 5 metres long; it formed along the contact of a thin chert interlayer and strongly brecciated basalt. The skarn consists of grossular garnet with less actinolite, epidote and pyrrhotite.

A sample from the Billican area taken across 3 metres yielded 0.34 gram per tonne gold, 82.29 grams per tonne silver, 3.2 per cent zinc, 0.07 per cent copper and 1.83 per cent lead (Assessment Report 8839 (quoted from a previous study)).

In 1923, Cairnes also reported the presence of pyrite, chalcopyrite, stibnite, arsenopyrite and galena. One specimen of solid ore taken at that time, composed mainly of pyrrhotite and sphalerite but also containing some stibnite and a little galena, assayed 1.71 grams per tonne gold, 323.32 grams per tonne silver, 40.30 per cent iron, 10.66 per cent lead, 2.66 per cent antimony, 7.15 per cent zinc and no arsenic (GSC Summary Report 1923 Part A, page 74).

By 1923, development work on the Billican consisted of a great deal of surface stripping, opencuts and the driving of an adit to a length 13.7 metres.