The Kleanza copper prospect (Croesus claims 1-130) covers Kleanza Mountain, about 12 kilometers north east of Terrace. Kleanza Mines Limited staked the initial Croesus group in 1965-66. During 1967-68, exploration work continued on the Croesus, Excelsior, Gem (103I 136) and other properties.

Granodiorites of the Cretaceous to Tertiary Coast Plutonic Complex intrude recrystallized mafic volcanic rocks of the Lower Jurassic Hazelton Group. The rocks are intensely sheared and contain numerous quartz stringers over a 12 metre width. The quartz veins trend north and contain disseminations and blebs of pyrite and chal- copyrite. A 1.2 metre sample assayed 1.4 grams per tonne gold, 13.7 grams per tonne silver and 0.3 per cent copper (Geological Survey of Canada Memoir 212).

The mineralization occurs within migmatized intrusives and vol- canics, marginally-outward of the intrusive complex. The rocks are soft-chloritized dark green andesitic tuff or amphibolite-diorite.

Several trenches have been blasted and bulldozed in chloritized and carbonate altered dark green andesite over a 60 by 20 metre area. Within this area, the andesite is mineralized by pyrite and quartz- carbonate-chlorite veins and minor chalcopyrite. Samples from the mineralized zone include a 1.2 metre chip sample which assayed 0.3 per cent copper, 13.7 grams per tonne silver and 1.37 grams per tonne gold. Another 1.5 metre chip sample assayed 0.2 per cent copper, 1.7 grams per tonne silver and 1.03 grams per tonne gold (McClintock, 1987).

Decade Resources Ltd. re-sampled the Excelsior showing as part of their Terrace Gold property exploration program in 2019. Thirty three grab samples were collected from the principal, SE-exposed and cleaned face (and sub-crop along this face) of the Excelsior showing. The diorite host rock is locally fractured, though usually shearing appears to obliterate incipient (and primary?) fractures. Sulfide mineralization include locally variable amounts of pyrite (trace - 7%) and minor chalcopyrite (usually trace - 1%). Locally occur traces of secondary malachite. Moderately common is also limonite. The low-grade gold, silver and minor copper mineralization is almost pervasive and relatively uniform within the limits of the showing. Interestingly, the elevated concentrations of gold show a very strong positive correlation with elevated tellurium and bismuth. (Assessment Report 38909).