The Sulphurets-Mitchell Creek area is underlain by rocks of the Lower Jurassic Unuk River Formation, Hazelton Group. These rocks includes green to grey volcanic epiclastics, and a sequence of domi- nantly fine-grained marine sediments. A third sequence of massive red and green volcanic sandstone and conglomerates form the highest peaks capping the stratigraphic sections.

The Bornite zone is locallized at the contact between a south- east-trending Jurassic diorite or monzonite body that cuts the ande- site tuff country rock. The stock hosts disseminated pyrrhotite and shows up as a pronounced magnetometer anomaly. Three trenched and two short diamond-drill holes have been completed on the prospect by late 1988.

Despite its name there is very little bornite in the zone; the mineralization is mainly chalcopyrite and tetrahedrite occurring as disseminations and in small veins within the andesite tuff. Bornite occurs as minor, but distinctive grains, and trace amounts of covel- lite have been reported. Assays from this showing range up to 1.86 per cent copper and 2.74 grams per tonne gold.