The West Side copper showing lies 80 metres southeast of the Tulameen River and 9 kilometres west-southwest of Tulameen.

The occurrence is hosted in hornblende clinopyroxenite of the Early Jurassic Tulameen Ultramafic Complex, a zoned Alaskan-type intrusive complex. The showing is 500 metres north of the dunite core of the complex.

The clinopyroxenite is mineralized with chalcopyrite and cut by quartz veinlets. Pyrite and magnetite are also reported. A grab sample of clinopyroxenite, with 1 per cent disseminated chalcopyrite and quartz veinlets up to 3 millimetres in diameter, analysed 0.149 grams per tonne gold, 0.168 grams per tonne platinum and 11.1 grams per tonne silver (Assessment Report 17280, page 9, sample W402). A second sample yielded 1.349 per cent copper (Assessment Report 17280, page 9). A chip sample taken across 6 metres of mineralized rock assayed nil gold, nil silver and 0.5 per cent copper (Minister of Mines Annual Report 1929, page 279).

Across the Tulameen River, three hundred metres southwest, a shear zone in gabbro has been traced north-northeast from the north bank of the river for 300 metres. The zone contains a quartz vein stockwork mineralized with pyrite and chalcopyrite. A chip sample across 1 metre analysed 0.182 per cent copper and 3.2 grams per tonne silver (Assessment Report 12190, page 8, sample 87703). A second sample from a nearby quartz vein with abundant pyrite yielded greater than 0.40 per cent copper (Assessment Report 7944, page 4). A sample of sorted ore assayed 10 grams per tonne gold, 34 grams per tonne silver and 0.6 per cent copper (Minister of Mines Annual Report 1932, page 139).