The Joh 3 occurrence was located on the southern portion of the Joh 3 claim, about 1.4 kilometres west of Darb Lake.

The area is underlain by Upper Triassic Takla Group volcanic rocks. These comprise porphyritic andesite and banded tuff. A porphyritic hornblende monzonite stock of the Early Jurassic Hogem batholith intrudes the volcanics, northeast of Johanson Lake. Recent mapping to the south has redefined the Hogem batholith as part Intrusive Complex (Open File 1992-11). The volcanics are hornfelsed and contain bands of amphibolite, within 300 metres of the intrusive contact. West of Darb Lake a diorite to monzonite stock, the Darb stock, intrudes the volcanics. The stock underlying Darb Lake and extending to the southwest consists of Early Jurassic quartz diorite. Diorite plugs, locally chloritized and carbonatized, commonly average 3 to 4 per cent disseminated pyrite.

Locally, the area is underlain by porphyritic andesite flows and tuffs intruded by monzonite-diorite stocks and granite-granodiorite of the Hogem batholith.

Disseminated chalcopyrite and pyrite occur in locally chloritic diorite, in a shear zone 3-metres wide and in quartz veins. The quartz veins are 1 to 2 metres thick and 100 metres long. The vertical shear zone trends 150 degrees.

The highest gold assay on the Joh property came from a sample of the shear zone. The chip sample (WR05) assayed 5.9 grams per tonne gold and 0.1338 per cent copper over 1 metre (Assessment Report 21782).