Lasqueti Island is dominated by dark, grey-green amygdaloidal and agglomeratic basalt of the Upper Triassic Vancouver Group, Karmutsen Formation. Regional bedding strikes northwest and dips moderately northeast. The volcanic rocks are locally intruded in the False Bay area by a north-northeast trending stock of the Early to Middle Jurassic Island Plutonic Suite quartz diorite. Narrow shear zones along the stock margins are common and locally contain minor quartz veining. Some hornfelsing of the basalt is also common along the quartz diorite contact but is not significant on a large scale.

Seams of massive sulphide mineralization in the area are often associated with the shear zones along the quartz diorite contact. These zones are narrow, less than 2 metres wide, strike from 010 to 040 degrees and are evident in basalt and quartz diorite.

The Old Bill occurrence area is underlain by amygdaloidal basalt of the Karmutsen Formation, which hosts a shear zone 50 centimetres wide striking 080 degrees and dipping 80 degrees north. The zone contains variable pyrite, chalcopyrite and narrow pyritic quartz veins. The zone has been developed by a short adit (Old Bill adit). A sample from the quartz vein assayed 0.87 per cent copper, 6.41 grams per tonne gold and 17.1 grams per tonne silver (Assessment Report 16086). Another short adit, the Aladdin adit, is 50 metres west of the Old Bill adit and is developed on the same shear zone. Open cuts above and to the east of the Aladdin adit reveal a second, parallel, but flat-dipping shear zone hosting massive chalcopyrite and pyrite. A sample from here assayed 1.12 per cent copper, 5.47 grams per tonne gold and 32.2 grams per tonne silver (Assessment Report 16086).

The Old Bill occurrence differs from the nearby Juneau (092F 133), Venus (092F 131) and St. Joseph (092F 132) occurrences in that the shear zone strikes east as opposed to north-northeast.