The Spokane occurrence is located on the Munn Creek slope, within a kilometre west and approximately 4.8 kilometres by road from Ainsworth. The claims lie in a north-west–trending line across the southwest corner of the Ainsworth townsite.

Regionally, the area is underlain by hornblende schists, limestone and banded quartzite of the Upper Mississippian to Permian Milford Formation and basaltic volcanic rocks of the Carboniferous to Permian Kaslo Group. Granodioritic intrusive rocks of the Middle Jurassic Nelson Batholith are exposed to the west.

The occurrence is hosted by quartzites, hornblende schists and siliceous limestones of the Mississippian to Permian Milford Formation intruded by some lamprophyre dikes or sills, less than 2.5 metres thick, that closely conform to bedding and foliation.

The deposit consists of two subparallel veins that conform to bedding and foliation. The two veins are less than 2 metres apart, and merge and split locally. They are offset by small sinistral or dextral northwest cross-faults. A gouge and breccia band, less than 7 metres thick, commonly occurs along the western vein. The ore occurs as lenses scattered along the vein or at the intersection of the northwest cross-faults. The ore consists of massive cubic to fine-grained and sheared galena with some sphalerite in a massive to porous gangue of quartz. Fragments of quartzite occur in the vein.

Work History

In 1893, the claims were Crown granted to the Pacific Bullion M. Co. The owners worked the property from 1888 to 1896 and from 1915 through 1920. Leasers operated the mine from 1921 to 1929.

By 1920, the deposit had been developed by two adit levels. The upper level, 61 metres below the outcrop, was driven for more than 274 metres along the vein. More than 122 metres of this was in an ore-shoot that was stoped through to the surface. The lower adit was started not far from the portal of the upper and only 8 metres vertically below it, and driven for 110 metres on the fissure. The last 67 metres of this tunnel was on the main ore zone and 55 metres of this part of the drift has been stoped through to the level above.

The Maestro Silver Lead Mines Ltd. was formed in 1937 to develop the Maestro and Spokane mines, but no work was done and the company became defunct in 1940. Ainsworth Vines Ltd. formed in 1936 to operate the Banker mine, gained control of the Spokane occurrence, and resumed development work in 1941. In 1942, Ainsmore Mines Ltd. (later Ainsmore Consolidated Mines Ltd.) was formed to operate the Spokane mine. A shaft was sunk for 30 metres from the lower adit and from this new level 22 metres of drift and a raise were put in. Yale Lead & Zinc Mines Ltd. acquired the property in 1949, and leasers worked the mine intermittently through 1957.

In 1979, David Minerals Ltd. conducted a program of geochemical (stream and silt) sampling on the area as the Peanut Butter claims of the Ainsworth property.

In 2010 and 2012, David Wallach prospected and sampled the area as the Ainsworth property. In 2010, a grab sample (269056) from an old ore cart yielded 0.75 per cent copper, 23.4 per cent lead, 5.07 per cent zinc and 95 grams per tonne silver (Assessment Report 32281). In 2012, two undescribed rock samples (1986607 and 1986609) from the occurrence area yielded values of up to 0.82 per cent lead, greater than 1.00 per cent zinc and 10.6 grams per tonne silver (Assessment Report 33426).

In 2019, Bill Mckinney conducted a program of prospecting, rock sampling and aerial photo structural interpretation on the Ainsworth property. In 2023, Turnagain Resources Inc. conducted a further program of prospecting, rock sampling and aerial photo structural interpretation on the Ainsworth property.