The South Side showing of the Coles property area is underlain by a sequence of volcanic and sedimentary rocks of the Lower Jurassic Telkwa Formation of the Hazelton Group. Host rocks consist of thick-bedded purple to green lapilli tuffs and volcanic breccias dip steeply northwest and are commonly cross-cut by intermediate dikes. Black mudstone and siltstone occur in the vicinity.

The South Side showing is associated with a northwest trending system of veins that contains both northwest trending veins and north to northeast trending veins. It is an acutely branching array of veins that split, splay and horsetail. It is an acutely branching array of veins that split, splay and horsetail. The individual veins are associated with minor shears and pinch and swell from stringer-stockworks to masses up to and in excess of 3 metres width. Veins dip steep (60 degrees) to vertical. The overall mineralized vein system is traceable intermittently for in excess of 4 kilometres. Vein quartz types include massive, banded, vuggy and coxcomb quartz generally white in colour but locally beige, grey, clear, red and rarely amethystine. At least 10 discrete zones or showings have been documented and sampled over part of the 4 kilometre length. Most of the showings are low in sulphides containing less than 1 per cent pyrite, locally to 15 per cent.

The South Side showing consists of a grey to milky, fine grained quartz and quartz breccia vein, to 3 metres in width. Minor pyrite and chalcopyrite are present. Sampling of the showing in 1987 gave a maximum of 0.132 gram per tonne gold and 4.4 grams per tonne silver with anomalous mercury, arsenic and tellurium (Assessment Report 16677). It appears that the South Side showing is located on the same major shear zone as the High View and Low View showings. The showing was reported to have been discovered prior to 1987.

See the Main Creek showing (093E 110) for further geological and work history details.