A number of mercury showings occur along the Pinchi Fault zone. The Pinchi Fault separates the Mississippian to Triassic Cache Creek Group from the Upper Triassic Takla Group. The fault has provided zones of permeability for the passage of mercury-bearing hydrothermal solutions in a number of places along its length. The origin of the mercury mineralization is not yet clear and in many places there are no obvious sources of heat or origin of the metals.

The Dickinson Mountain showing consists of cinnabar in Cache Creek Group limestone 800 metres east of Fort St. James. The Pinchi Fault is interpreted to pass through the area a short distance to the east of the showing.