The Sulphurets-Mitchell Creek area is underlain by rock of the Lower Jurassic Unuk River Formation, Hazelton Group. These include green to grey volcanic epiclastics, and a sequence of dominantly fine- grained marine sediments. A third sequence of massive red and green volcanic sandstones and conglomerates form the highest peaks capping the stratigraphic sections.

The mineral occurrence is reported to lie entirely within a "tectonic shear zone". This zone contains all of the significant gold anomalies. This zone covers an elongated northern trending area 800 to 900 metres wide and 2 kilometres long. The zone is flanked by comparatively unaltered or weakly altered, fine-grained, brownish green clastic sediments and submarine volcanic rocks on the east, and by a thick unit of basaltic andesite on the west. This tectonic zone is typically composed of moderately to strongly altered and sheared rocks interpreted to be of volcanic, subvolcanic or plutonic origin. Most of the altered zone can be described as a sericite schist, how- ever, andesitic tuffs and flows, and feldspar porphyry dykes and possibly flows, can be recognized in the less altered zone. A later formed "swarm" of fine-grained, weakly altered andesite dykes cuts across the schistosity. Both the altered zone and dykes have been cut by faults. Minor sections of silty shale and siltstone occur on the western and eastern margin of the altered zone.

The C zone occurs within a fault-bounded block of ground that also contains the L zone (Lake zone). Host rocks include andesitic tuffs altered to sericite schist. The mineralization is probably continuous between these two zones, but of sub-economic grade. The west bounding fault is the B zone Fault. The eastern bounding fault is the Camp Fault.

The C zone consists of pyrite mineralized quartz veins and silica-cemented breccias. Mineralization consists of gold, with sub- economic amounts of values copper and silver. A weighted average of 9 trench samples (Trench C2) resulted in 3.19 grams per tonne gold and 7.20 grams per tonne silver over an 18 metre length (Assessment Report 16616). Alteration in the C zone is predominantly sericite. Quartz, pyrite, epidote and chlorite alteration are also reported.