The Bornite prospect is located on the east slope of Holmes Mountain, which forms the steep west bank of Hayes Creek, 9 kilometres east-northeast of Princeton.

The region north of the Similkameen River is underlain to the east by intrusive rocks of the Early Jurassic Bromley batholith, and to the west by volcanics and minor sediments of the Upper Triassic Nicola Group.

The east slope of Holmes mountain is underlain by andesites, basalts and minor sediments of the Nicola Group, near the western margin of the Bromley batholith. The contact between the Nicola Group rocks and the Bromley batholith generally trends north-northwest along Hayes Creek. The volcanics are cut by pulaskite and quartz porphyry dykes that are likely related to the Bromley batholith.

Copper mineralization is hosted in one of these dykes, a dioritic quartz porphyry dyke, about 23 metres wide. The dyke strikes north for at least 900 metres, and contains disseminated chalcopyrite and pyrite. This prospect was explored by two trenches and one adit between 1908 and 1915.