The Mobbs mine property is located west of the Lardeau River between Rusty and Rapid creeks, on Lot 6475, in the Slocan Mining Division.
Regionally, the area lies within the Selkirk Mountains of southeastern British Columbia. The occurrence is within the Kootenay Arc, a curving belt of highly deformed metasedimentary and metavolcanic rocks which includes the Upper Proterozoic Horsethief Creek Group, the Upper Proterozoic to Lower Cambrian Hamill Group, the Lower Cambrian Badshot Formation, and the Paleozoic Lardeau and Milford groups. The volcano-sedimentary sequence is intruded by numerous Paleozoic to Mesozoic granitoid plutons.
The Lardeau River area of the Selkirk Mountains is mainly underlain by massive pillow lavas, volcanic breccia and green phyllitic rocks of the Index Formation and by grey-green mica schist of the Broadview Formation. Grey phyllitic rocks and marble of the Milford Group are exposed near the edges of the Mesozoic Mobbs Creek, Rapid Creek and Poplar Creek stocks. All rocks have undergone regional metamorphism to middle or upper greenschist facies. Rocks of the Milford Group have also been affected by thermal metamorphism (Geological Survey of Canada Bulletin 193).
Sulphide mineralization is present in quartz veins that are both oblique and parallel to the foliation of the enclosing calcareous schists and phyllites of the Index Formation of the Lardeau Group. The G vein, a foliation parallel vein, is the best developed. It has been exposed in surface trenches and a crosscut 10 metres below the surface outcrop. From the crosscut, drifts were driven 20 metres east and 3 metres west along the strike of the vein. A winze was sunk from the crosscut for a depth of 25 metres to explore the downdip extension of the vein. The vein was faulted off 10 metres from the collar of the winze by a northeast-dipping fault and could not be traced beyond the fault.
The G vein within the underground workings varied from a few centimetres up to 1 metre in width and consisted mainly of white quartz with pyrite and galena. Sulphide minerals were concentrated in massive pockets which yielded high silver assays. A grab sample from a mineralized pocket assayed 3257 grams per tonne silver and 77.5 per cent lead (Minister of Mines Annual Report 1914).
Veins which are oblique to the foliation are mostly emplaced along fissures and faults with well-developed gouge. The quartz veins are 60 to 120 centimetres wide and mineralized with pyrite, galena and free gold. At least five veins have been identified and developed by several adits and crosscuts connected to a vertical shaft. Grab samples from the veins yielded gold values ranging from 3.4 to 68 grams per tonne gold with most vein samples averaging about 8 grams per tonne gold (Minister of Mines Annual Report 1914).
Limited production from the Mobbs mine in 1916 and 1939 yielded 40,496 grams of silver, 62 grams of gold and 1769 kilograms of lead from 14 tonnes mined.