Regionally, the area is underlain by Upper Triassic Karmutsen Formation (Vancouver Group) volcanic rocks intruded by granodiorites of the Early to Middle Jurassic Island Plutonic Suite. These rocks are unconformably overlain by conglomerates and sandstones of the Upper Cretaceous Nanaimo Group. Dacite dykes of the Late Eocene to Early Oligocene Mount Washington Intrusive Suite (previously Catface Intrusions) cut the overall sequence and numerous northwest trending shear zones and faults occur.

The Vulcan occurrence is underlain by Karmutsen Formation massive, chloritic andesitic pillow lavas, flows and tuffs intruded by a slightly clay-chlorite-argillite altered biotite granodiorite of the Island Plutonic Suite. Conglomerates with lesser sandstone of the Nanaimo Group occur at predominantly higher elevations. Mineralization consists of shear zone-hosted auriferous quartz veins. The shear structures are observed in all units but mineralized quartz veins occur in shears in the andesites. Pronounced alteration halos consisting of bleaching, chlorite, limonite with lesser sericite and silicification, are associated with the shear zones in the conglomer- ate and granodiorite. Shear zone alteration in the andesites con- sists of chlorite with local limonite and silicification.

Propylitized andesites host the Vulcan shear zone which strikes 039 degrees and dips 75 degrees northwest. Chlorite and carbonate content and degree of brecciation appears to increase as you approach the shear zone. Minor hematite is observed in some of the shears. Mineralization is absent in the andesites outside the contacts of the shear zone. The zone consists of intensely sheared andesite hosting discontinuous quartz and/or sulphide lenses and has been traced on surface for 37 metres. The zone ranges in width from 40 to 150 centimetres. Discontinuous lenses of quartz and sulphides occur on the footwall and hangingwall of the shear; the width of these structures ranges from 2 to 15 centimetres. Mineralization consists of blebs and pods of pyrite with local traces of chalcopyrite, galena and sphalerite. The pods range from 2 to 10 centimetres wide and can be 30 centimetres in length. A rock chip sample taken from the Vulcan shear zone from the upper level assayed 8.09 grams per tonne gold (Assessment Report 17258).

Past work on the Vulcan shear included a shaft, a drift from the shaft 5 metres below the shaft collar (upper level) and a crosscut adit (adit level) driven 12 metres below the shaft collar. The lower level (or adit level) is on a parallel structure to the Vulcan shear which is developed by the shaft and the upper level. A second zone, the E shear zone within the Vulcan shear zone, was also tested by a shaft. On the adjoining Austrian claim (Lot 49), 90 metres east, a shaft was sunk on a 60 centimetre wide auriferous quartz vein hosted in another shear zone in andesite.

A total of 15 tonnes of ore was mined in 1938 and 1940 , yielding 1,119 grams of gold, 405 grams of silver and 10 kilograms of copper.