The Grayling Creek showing occurs at two locations in Grayling Creek valley, at an elevation of 1410 metres on the west side and 1675 metres on the east side of the valley. The valley and surrounding slopes are underlain by Cambrian to Silurian platformal sequence of carbonates, quartzites and siltstones. Lower Cambrian Atan Group dolomites and quartzites, intruded by mafic dykes, are conformably overlain by a sequence of Cambrian to Ordovician Kechika Group arenaceous dolomites and limestones and Silurian Nonda Formation siltstones.
Mineralization occurs at the same stratigraphic level on both sides of the valley, at the top of the Atan Group immediately below the Kechika Group. The showings consist of irregular pods, open space-fillings, and veins of massive pyrite, bornite, chalcopyrite and tetrahedrite in silicified fractured dolomite. Fractures are completely healed by crystalline calcite. A composite chip sample of massive sulphide mineralization graded 1.4 per cent copper and 10.2 grams per tonne silver (Assessment Report 21437).