The Gunn prospect is located near the eastern margin of the Stikinia Terrane in south central British Columbia. The dominant rock types in the region belong to the Mississippian to Triassic Cache Creek Group. These consist of metabasalt, limestone and argillaceous metasediments, intruded by the diorite to quartz diorite Granite Mountain pluton. Jurassic sedimentary rocks overlap both the Cache Creek and Quesnellia terranes to the north and east of the pluton. To the west older rocks are largely obscured by plateau basalt of probable Miocene age.

The Granite Mountain Pluton has been regionally metamorphosed (greenschist facies) and deformed along with the enclosing Cache Creek Group. The Cache Creek Group and the margins of the Granite Mountain Pluton record effects of ductile deformation. The main body of the pluton has been cataclastically deformed.

Mineralization in the pluton consists mainly of pyrite, chalco- pyrite and molybdenite deposited in stockworks in four mineralizing phases during deformation and metamorphism.

The Gunn prospect is underlain by quartz diorite of the Granite Mountain Pluton in which two zones of mineralization have been detected. Malachite, probably after chalcopyrite, occurs in a shear zone where a stockwork of quartz and quartz-chlorite veins has developed. Two drill holes in this zone averaged 0.2 per cent copper (Assessment Report 1641). The second zone is a band contain- ing malachite and lesser azurite. The zone is parallel to the foli- ation of the Granite Mountain Pluton over a distance of about 60 meters, and then deflects and extends along a quartz vein for 76 meters. The quartz vein is 7 to 20 centimetres wide and contains molybdenite. Chalcopyrite, chalcocite and pyrite mineralization in the band occurs as disseminations and on talcose slip surfaces.

Drill indicated reserves for the A and B zones in 1971 were 861,745 tonnes grading 0.28 per cent copper (Statement of Material Facts January 17, 1972 - Gunn Mining Ltd., E.P. Sheppard, March 10, 1971).