Bonanza Peak is part of the Wrangellia Terrane. Copper deposits are found at the disconformity between the Upper Triassic Chitistone limestone and underlying Permian Nikolai greenstone. Copper is found as polymetallic replacement deposits in the fault planes, fractures and joints. Minerals include chalcocite, bornite and chalcopyrite, with associated malachite, azurite, and cuprite. Native copper can also be found in the greenstone.: The deposits were mined for their spectacularly high-grade copper ore which exceeded 70 percent.