Four showings occur in quartz diorite of the Early to Middle Jurassic Island Plutonic Suite. Much of the rock is porphyritic and cut by dykes. The showings are on the steep, often precipitous, northwestern slopes of Big Interior Mountain.
At approximately 975 metres surface cuts and stripping have been done across a narrow draw exposing mineralized quartz veins. The main vein pinches and swells from 10 to 75 centimetres, strikes 040 degrees and dips about 35 degrees to the southeast. The vein contains pyrite, sphalerite, minor of chalcopyrite, and a coating of covellite occurs on the sphalerite.
Three samples were taken over a section of 76.2 centimetres normal to the footwall. The first sample, 8.9 centimetres in width, containing quartz and sulphides at the footwall, assayed 111.09 grams per tonne gold and 68.57 grams per tonne silver. The second, overlying the first, was made up of 35.6 centimetres of wallrock cut by veinlets of quartz and sulphides and contained 17.14 grams per tonne gold and a trace of silver. The third sample, overlying the second, consisted of 31.7 centimetres of a decomposed layer contain- ing some quartz and sulphides and assayed 20.57 grams per tonne gold and a trace of silver (Bulletin 8).
The second showing is about 500 metres to the south where a cut exposes a 10 centimetre vein. South of this, on a westerly facing bluff, a narrow shear zone occurs. This zone is marked by a rusty stain, 25 to 76 centimetres wide, extending for about 30 metres between 1160 and 1180 metres elevation. A narrow fissure contains gouge, some pyrite, sphalerite and a little galena. It strikes due east and dips about 35 degrees north.
The third zone is about 300 metres southwest from the second and occurs intermittently for 120 metres on the northeastern side of a draw which runs west of north. Shears and branching fractures cut the quartz diorite and in the southern half of the exposure follow and cut through andesitic dyke rock. The major shearing strikes west of north and dips 35 to 55 degrees northeast. Sulphides are developed with quartz in the fissures and as disseminations in the wallrock. Some of the quartz is heavily mineralized with pyrite, sphalerite and chalcopyrite. Covellite is found as coatings on sphalerite and microscopic studies have detected the presence of gold. One 25 centimetre sample assayed 139.20 grams per tonne gold (Bulletin 8, page 63).
A short distance to the southeast, a rusty shear is exposed on steep bluffs from 1430 to 1450 metres elevation. This shearing strikes from about 070 to 090 degrees and dips from 35 to 55 degrees north. Lenses of quartz, with pyrite, arsenopyrite, chalcopyrite, and some sphalerite are developed in the sheared quartz diorite. A 25 centimetre sample of quartz with sulphides contained 2.74 grams per tonne gold (Bulletin 8, page 64).
