The Grayling showing, exposed in Grayling Creek valley, is underlain by a Cambrian to Silurian platformal sequence of carbonates, quartzites and siltstones.
Lower Cambrian Atan Group dolomites and quartzites are conformably overlain by Cambrian to Ordovician Kechika Group arenaceous dolomites and limestones, which, in turn, are conformably overlain by Silurian Nonda Formation siltstones.
The Grayling showing consists of irregular pods of massive pyrite, bornite, chalcopyrite, pyrrhotite, minor marcasite and tetrahedrite. These pods, up to 40 centimetres thick and traceable for up to 40 metres along bedding planes, are hosted within tightly-packed sandy dolomite of the Kechika Group. Grab samples of massive sulphide material grade 1.70 per cent copper, 0.50 per cent nickel, 0.56 per cent cobalt, 27.8 grams per tonne silver, and conain anomalous platinum values (Assessment Report 19124).