The Cuba property is situated at 1707 metres elevation above sea level on the east side of the ridge that separates Miller and Shea creeks, in the Slocan Mining Division. The property includes underground workings on two separate veins exposed on the Cuba Reverted Crown grant (Lot 4168).
In December 1935 the Sunshine Silver Lead Co. Ltd. was organized to develop a number of claims in the area including the Oregon (082FNW044). In 1936 the name was changed to the Silver Ridge Mining Co. Ltd. Extensive bulldozer stripping was done on this property in 1937 and several leads uncovered.
An adit was driven on the Jan claim and a shaft sunk 15.2 metres to a point where the lode was cut off by a flat fault. A second adit, driven lower down, picked up the vein below the fault at a point 38 metres from the portal. The vein was followed for 41 metres in a north 55-degree west direction.
An adit was driven on the Belle claim for 122 metres in a northwest direction but no mineralization was found.
Regionally, the area lies on the western margin of the Kootenay Arc, in allochthonous rocks of the Quesnel Terrane. In the vicinity of the occurrence, the Quesnel Terrane is dominated by very fine grained clastic sedimentary rocks of the Upper Triassic Slocan Group that include locally weakly metamorphosed argillite, quartzite, limestone and some tuffaceous rocks. These sedimentary rocks are intruded by dikes, sills and stocks of varied composition and origin. Permian and/or Triassic Kaslo Group metamorphosed volcanic rocks occur to the north of the Slocan Group rocks. Middle Jurassic Nelson intrusions are immediately south of the Slocan Group and are inferred to be the source of granitic to pegmatitic sills and dikes found in the area. The Nelson intrusions comprise at least six texturally and compositionally distinct phases ranging from diorite to lamprophyre. The most dominant phase is a medium to coarse grained potassium feldspar porphyritic granite (Paper 1989-5).
The occurrence is hosted by predominantly interbedded black argillite, quartzite and limestone of the Slocan Group. The sedimentary rocks have been folded, fractured, faulted and regionally metamorphosed to greenschist facies. The regional northwest trending asymmetric Slocan syncline is thought to be Middle Jurassic and is the first recognizable deformation in the sequence. Several fault structures are evident and host vein mineralization. Later stage normal and thrust faults and shearing have chopped, deformed and remobilized the veins and mineralization. Drag features are also present.
Two separate veins are known on the Cuba Reverted Crown grant, the Jan and the Belle. The veins have been explored with two major adits and several opencuts. A 15 metre deep shaft was also sunk to investigate the Jan vein.
The Jan vein is about 5 to 15 centimetres wide but can locally widen up to 50 centimetres. The vein strikes 125 degrees and dips 50 to 70 degrees southwest. It is very oxidized and locally contains argentiferous galena and sphalerite mixed with calcite and gouge.
The Bell vein is about 30 metres below and 60 metres northeast of the Jan vein. The vein has been followed for about 120 metres in a west-northwest direction in the underground workings. The vein dips 50 to 70 degrees south and locally contains argentiferous galena. It varies from a mere fracture up to 10 centimetres in width. The vein is cut and displaced by several low angle faults subparallel to bedding. A sample collected from the vein in 1939 assayed 60 per cent lead and 3428 grams per tonne silver (Property File - Prospectus, Silver Ridge Mining Company, 1939).
Production from the Cuba property in 1938 and 1940 yielded 49,671 grams of silver, 14,124 kilograms of lead and 1459 kilograms of zinc from 24 tonnes mined.
