The Kingston prospect occurs on both sides of Horsefly Gulch, a west-flowing tributary of Hedley Creek, about 1.5 kilometres northeast of the town of Hedley.

The region northeast of Hedley is underlain by a sequence of interbedded limestone, siltstone and argillite of the Upper Triassic Hedley Formation (Nicola Group), which is intruded by stocks, dykes and sills of diorite and gabbro of the Early Jurassic Hedley Intrusions. All units are cut by granodiorite of the Middle Jurassic Cahill pluton. The sediments dip 15 to 35 degrees southwest and are extensively skarn-altered.

Mineralization occurs discontinuously over a 700-metre length in a northwest-trending band of limestone and siltstone up to 250 metres wide. The sediments are bounded to the northeast by hornblende porphyritic diorite of the Toronto stock (Hedley Intrusions) and to the southwest by a 100-metre wide granodiorite dyke originating from the Cahill pluton. The sediments are cut by numerous sills and dykes of diorite and gabbro and by a few rhyolite and lamprophyre dykes.

Skarn containing garnet, epidote, diopside and amphibole occurs at or near the diorite contact on the Warhorse and Kingston claims to the southeast. The skarn is mineralized with disseminated pyrrhotite, pyrite, chalcopyrite, arsenopyrite and galena. Samples from the dump on the Warhorse claim are reported to average around 6 per cent copper (Geological Survey of Canada Memoir 2, page 200). A sample taken over 1.5 metres in the incline shaft on the Kingston claim assayed 3.4 grams per tonne gold, 26.7 grams, per tonne silver and 2.64 per cent copper (Minister of Mines Annual Report 1926, page 218).

Garnet-epidote-diopside skarn occurs within 60 metre of the Toronto stock on the north side of Horsefly Gulch. This skarn has a higher gold and a lower copper content than the previously described skarn on the Kingston and Warhorse claims. Underground workings expose a body of mineralization in skarn up to 4 metre thick that dips gently to the southeast. The zone contains arsenopyrite and minor chalcopyrite and native gold. The gold occurs as small thin flakes in minute fractures. A chip sample of arsenopyrite-rich ore, taken from an adit on the Metropolitan claim, assayed 14.4 grams per tonne gold and 2.7 grams per tonne silver over 2.0 metres (Minister of Mines Annual Report 1926, page 218).

Mineralization on all three claims has been periodically explored since 1899. Most of the work was conducted by Kingston Gold and Copper Mining Ltd. between 1905 and 1909, and involved trenching and underground development. G.M. Explorations Ltd. carried out geological, geochemical and geophysical surveys and 613 metres of diamond drilling between 1969 and 1973.