The Monitor prospect is located on Crown grants Lot 651 and Lot 544 on Carbonate Mountain, one kilometre northwest of Malachite Creek.

In 1888, a 26-metre long tunnel was constructed on Crown grant Monitor (Lot 651). Two open cuts also occur on this grant.

The occurrence is located in the Purcell Mountains and the area is underlain by northwest-trending metasediments of the Upper Proterozoic Horsethief Creek Group. Regionally, this group consists of slates, argillites, quartz pebble conglomerates, grits and minor limestone.

The prospect includes a 0.6 to 1.5-metre wide vein. It trends in a northeast to southwest direction with a near-vertical dip. The vein can be traced across the properties. The vein contains antimony sulphide (Stibnite) located in micaceous slates and schists, having a dike of granite gneiss as its hanging wall. Above the vein is another "lode" of highly argentiferous galena, impregnated with minute specks of tetrahedrite.

The ore averages 1714.29 grams per tonne of silver (Minister of Mines Annual Report 1980, page 373).