The Makalu claims are located about 80 kilometres east-southeast of Revelstoke. They lie on the east side of the Duncan River, approximately two kilometres north of the mouth of the Westfall River.

The tungsten mineralization was located by personnel from the Union Oil Co. of Canada during a preliminary geological and geochemical program in 1980. At that time, soil surveys delineated several areas with moderate to highly anomalous tungsten along the southern margin of a granodiorite stock in close proximity to mineralized outcrop. In 1982, Union Oil mapped the geology and prospected the area.

The area is predominately underlain by highly deformed metasedimentary rocks of the Upper Proterozoic, Horsethief Creek Group. Within the occurrence area, the rocks are foliated, folded and regionally metamorphosed (greenschist facies). These strata have been discordantly intruded by a small elliptical stock of biotite granodiorite. Carbonate horizons adjacent to the stock have been partly converted to skarn.

Limestone has been recrystallized and contact and regional metamorphism have produced amphibolite and hornblende schists, biotite-muscovite schists and tremolite skarn and iron rich skarn.

The tremolite skarn contains biotite and/or actinolite and diopside. The iron-rich skarns contain abundant pyrite, pyrrhotite, epidote, actinolite and hornblende with or without garnet and diopside.

The iron-rich skarns contain scheelite and powellite bearing pods of massive pyrite and pyrrhotite. Chalcopyrite is disseminated within these zones. A grab sample assayed 0.23 per cent tungsten (Assessment Report 10721, page 12). Scheelite, galena and sphalerite were observed in a few narrow quartz veins cross cutting and adjacent to this zone. Minor amounts of molybdenite were observed in quartz veins within the granodiorite stock. Mineralized zones are low-grade, narrow, discontinuous and close to the contact zone.