The Mag prospect is located at 1110 metres elevation above sea level, northeast of Mount Lavina in the Slocan Mining Division.

Regionally, the area lies within the Kootenay Arc near the margins of the Ancestral North American Terrane. The Kootenay Arc is a curving belt of highly deformed metasedimentary and metavolcanic rocks which includes the Upper Proterozoic Horsethief Creek Group, the Eocambrian Hamill Group, the Lower Cambrian Badshot Formation, and the lower Paleozoic Lardeau Group. The volcano-sedimentary sequence is intruded by numerous Ordovician, Devonian and Mississippian granitoid plutons. The rocks have undergone regional metamorphism to middle or upper greenschist facies (Paper 1993-1).

The prospect is on the western limb of the Duncan anticline within dolomite and limestone of the Lower Cambrian Badshot Formation which forms a narrow complexly folded band that separates micaceous quartzite of the Mohican Formation (Hamill Group) to the east from the phyllites of the Lardeau Group to the west. On the property, the Badshot Formation is overturned, dips at low angle to the northeast and plunges northwest.

Mineralization is exposed in roadcuts and trenches over a strike length of 1.5 kilometres. It consists of gossanous zones locally containing galena and sphalerite in fractures. A total of 25 tonnes were mined between 1970 and 1984 to produce 26,062 grams of silver, 24 grams of gold, 11,208 kilograms of lead, 89 kilograms of zinc and 18 kilograms of copper.