The Excelsior Fraction prospect is located 3.0 kilometres west of the summit of Mount Wallace and 1.75 kilometres south-southeast of Beaverdell, British Columbia (Assessment Report 16772).
Initial prospecting began in the Beaverdell area in the late 1880s. The first ore was shipped in 1896. The major producing mines in the Beaverdell silver-lead-zinc vein camp, from west to east, were the Wellington (082ESW072), Sally and Rob Roy (082ESW073), Beaver (082ESW040), and Bell (082ESW030), with numerous other small workings throughout the area. A small quartz vein with galena was discovered on the Excelsior Fraction in 1901. In 1911, the claim was Crown granted to Vancouver and Boundary Creek Developing and Mining Co. Ltd. By 1934, the property was acquired as part of the Sally claim group by Sally Mines Ltd. By 1949, the property became part of the ground held by Highland-Bell Ltd., owner of the Highland-Bell (Beaverdell) mine. The Highland-Bell mine produced until 1991.
Granodiorite of the Westkettle batholith underlies most of the area. It has been intruded by small quartz monzonite porphyry stocks including the Eocene Beaverdell, Tuzo Creek, Eugene Creek and Carmi stocks. Other granitic porphyry stocks that intrude the Westkettle batholith are the Eocene Beaverdell porphyry. The Westkettle batholith has been correlated with the Nelson intrusions that have been dated by potassium-argon and uranium-lead methods as Middle Jurassic. The Westkettle batholith contains remnants of pendants and/or screens of metamorphosed Wallace Formation. The Wallace Formation is believed to be correlative with the upper (Permian) section of the Carboniferous to Permian Anarchist Group. Lithologies include metamorphosed andesitic tuffs and lavas, hornblende diorite porphyries, olivine gabbro and hornblendite, hornfels and minor limestone. The contact between the Wallace Formation and the Westkettle batholith is sinuous, trending north with gentle east dips. These are unconformably overlain by Oligocene tuffs and conglomerates and Miocene plateau basalts. Westkettle granodiorite or Beaverdell quartz monzonite are the dominant hostrocks. Mineralization rarely extends into the Wallace Formation to the east. A series of dikes, ranging in composition from quartz latite and quartz monzonite porphyries to hornblende andesite porphyries, are found throughout the area. In the Beaverdell camp, fine-grained, brown andesite dikes, referred to as Wellington-type dikes, are believed to be pre-mineralization. Quartz latite dikes are referred to as Idaho-type dikes and thought to be syn or post-mineralization.
Beaverdell silver-rich veins are found in a 3.0 by 0.8 kilometre belt, referred to as the Beaverdell silver, lead, zinc vein camp. The mineralized veins are fissure-hosted, formed along east-trending faults in the west portion of the Beaverdell camp and northeast- trending faults in the east portion of the camp. Faults have been classified into five types based on their orientation, with each type having common orientation, kind of movement and age relationship. The northeast-striking, high-angle normal faults pose the greatest obstacle to systematic exploration and mining, as these faults are commonly spaced a few metres apart dividing veins into short segments in a northwest-downward direction.
Vein-type mineralization of the Beaverdell camp is characterized by a high silver content. Mineralization is composed of galena, sphalerite and pyrite with lesser amounts of arsenopyrite, tetrahedrite, pyrargyrite, chalcopyrite, polybasite, acanthite, native silver and pyrrhotite. The gangue minerals in veins are mainly quartz with lesser amounts of calcite, fluorite and sericite with rare barite.
The Excelsior Fraction (Lot 1204s) adjoins the Wellington claim (082ESW072) and Sally claim (082ESW073) in the north and the Nodaway claim (082ESW068) and Duncan claim (082ESW032) in the south. The property is underlain by Westkettle granodiorite.
A quartz vein 20 to 30 centimetres wide and mineralized with galena, occurs in an east trending shear zone. An andesite dike (Wellington-type) roughly parallels the shear zone structure. A quartz latite dike (Idaho-type) strikes across both the andesite dike and shear zone. Past development consisted of adits.
