The Surprise Mountain area is underlain by rhythmically layered amygdaloidal, feldspar porphyritic and spherulitic basalt flows of the Upper Triassic Karmutsen Formation (Vancouver Group). Mineral- ized quartz and quartz-carbonate veins with variable sulphide content are associated with narrow, steeply dipping shear zones.

The Surprise occurrence is underlain by amygdaloidal basalt of the Karmutsen Formation cut by a shear structure striking 155 degrees and dipping 70 degrees southwest. The shear zone is 1.2 to 3 metres wide, locally silicified and traceable for 60 metres along strike. The zone hosts irregularly distributed quartz veins mineralized with pyrite, chalcopyrite, sphalerite and galena. A grab sample from a drusy quartz vein in a trench south of a shaft, assayed 5.73 per cent copper, 105.8 grams per tonne silver, 1.17 grams per tonne gold and 0.1 per cent lead (Assessment Report 18672).

Work done includes a shaft with very limited drifting. Several open cuts, pits and trenches occur to the south of the shaft.