The MM showing is located near the eastern margin of the Stikinia Terrane northwest of Granite Mountain in south central British Columbia. The dominant rock types in the region are metabasalt, limestone and argillaceous metasediments of the Mississippian to Triassic Cache Creek Group. These are intruded by the dioritic to quartz dioritic Granite Mountain Pluton and the (?) Cretaceous Sheridan Creek Pluton. The Granite Mountain Pluton has been affected by metamorphism (greenschist facies) and deformation along with the enclosing Cache Creek Group.

The MM showing is located near the northern margin of the Granite Mountain Pluton and comprises three pyrite-chalcopyrite zones within quartz diorite.