The Sunset skarn deposit is hosted by the Early Jurassic Rossland monzonite which intrudes the Lower Jurassic Elise Formation (Rossland Group) volcanics and greenstone. The host rock is comprised of a biotite-hornblende-augite monzonite stock which is medium-grained, grey to green in color and hosts magnetite, apatite, some sphene with chlorite, epidote and pyrite.

The ore from the Sunset tunnel is contained in a magnetite- skarn and consists of massive pyrrhotite and magnetite with a fair amount of chalcopyrite intermixed in a quartz and altered monzonite gangue. The massive magnetite shows good octahedral cleavage. A shaft was sunk on a 15 centimetre vein of ore. The ore was mined and shipped in 1898 and 1908 to the Trail smelter. A total of 30 tonnes of ore produced 373 grams gold, 809 grams silver and 99 kilograms copper.