The Horseshoe occurrence is located on Ellesmere Creek, approximately 1.3 kilometres northwest of the creek mouth on the west side of Howe Sound.

The area is underlain by Cenozoic-Mesozoic Coast Plutonic Complex quartz diorite, which contains a belt of schists and argillite of the Lower Cretaceous Gambier Group.

Mineralization, consisting of pyrite, pyrrhotite and apparently chalcopyrite, occurs in quartz lenses at the contact between quartz diorite and gossanous, micaceous schist.

In 1981, Raft Mines completed a program of rock sampling, trenching and an air photo fracture density analysis on the area as the Clare claim. In 1984, Black Queen Resources completed a 55.2 line-kilometre airborne geophysical survey on the area as the Doyle 1-2 claims. In 1986, Fontana Resources, completed a program of rock and soil sampling, geological mapping and a ground magnetometer survey on the area.