The Surprise Mountain area is underlain by rhythmically layered amygdaloidal, feldspar porphyritic and spherulitic basalt flows of the Upper Triassic Karmutsen Formation (Vancouver Group) overlain by a 15 metre thick subhorizontal unit of columnar jointed basalt. Mineralized quartz and quartz-carbonate veins with variable sulphide content, are associated with narrow, steeply dipping shear zones.

The Retriever occurrence is underlain by amygdaloidal basalt of the Karmutsen Formation cut by north trending and later(?) east trending shear structures. The shear zones host two quartz veins 30 metres apart. The northerly vein strikes in an east direction with 65 degree dips to the south and averages 60 centimetres wide. The second vein is 30 metres south and averages 91 centimetres wide. Mineralization consists of pyrite, chalcopyrite, galena and sphalerite. A grab sample from a pit assayed 0.97 per cent copper, 2.25 per cent lead, 6.46 per cent zinc, 37.1 grams per tonne silver and 0.61 grams per tonne gold (Assessment Report 18672).

Past work includes 2 shafts sunk on the veins and an adit which intersects both veins and connects with the shafts. Some limited production was recorded.