The Mountain Chief occurrence is located approximately 2 kilometres east of New Denver, British Columbia and 250 metres east of the Apex occurrence (082FNW001).

The Mountain Chief occurrence occurs on the Mountain Chief group, consisting of the Mountain Chief (Lot 498), Mammoth (Lot 1910) and Egypt (Lot 1922) claims. The Mountain Chief No. 2 (Lot 474) claim was added later. The earliest work on the property was conducted between 1892 and 1897. Development resumed again in 1921 by lessees. In 1925, a two-compartment jig was erected and operated to recover sphalerite from ore remaining in the old stopes and dumps. Workings were mainly on and near the northwest corner of the Mountain Chief claim. They consisted of nine adits varying from 30 to 152 metres in length. Two diamond-drill holes, totalling 40.5 metres, were drilled to investigate a possible extension of the mineralized zone to the south, in 1963?. The extension was not found. In 1973, New Denver Explorations Ltd. investigated the property.

The Mountain Chief occurrence is underlain by argillaceous and calcareous sediments, slate, limestone and tuff of the Triassic Slocan Group. These strata have a general strike of 040 degrees and dip 45 degrees southwest and are intruded by large porphyry dikes and a porphyritic granite stock. These metasedimentary strata are folded and fractured. The strong vein-lode comprising the Mountain Chief occurrence is hosted in limestone, slate and limy argillite.

Mineralization on the Mountain Chief property was hosted in a quartz vein-lode system striking from 040 degrees in the lower workings to 065 degrees on level No. 3 to 050 degrees on the surface. Fluorite is probably present as a gangue mineral with quartz. Ore consisted of galena and sphalerite with the latter increasing with depth. In the lower portions of the workings vein widths varied from several centimetres to 120 centimetres, containing bands of sphalerite up to 20 to 25 centimetres wide. The vein-lode is interrupted by faults which displace it to the east and divide the vein-lode into two distinct separate ore shoots. The northern ore shoot was the more extensive of the two.

Principal production was from the upper three levels of the workings which were stoped to the surface. Production records indicate 2989 tonnes were produced periodically from 1893 to 1942. From this, 10,884,805 grams silver, 311 grams gold, 913,963 kilograms lead and 183,052 kilograms zinc were recovered. Another 57 tonnes production is reported in the Minister of Mines Annual Report 1943, page A73. The ore was mined by hand and sent directly to the Trail smelter. Approximately 44 tonnes was reported mined in 1936 but was not shipped (Minister of Mines Annual Report 1936, page E52).