This is a copper-gold district in the Hoopa Indian Reservation in northeastern Humboldt County. Placer gold has been recovered from the Trinity River and by-product gold from the Copper Bluff copper mine, active in 1965. The placer deposits occur both in the present river channel and in older terrace deposits along the bank. The ore deposits at the Copper Bluff mine consist of mineralized schist and quartz veins containing gold associated with chalcopyrite, sphalerite, galena, and pyrite.
Symons, H. H., and Davis. F. F., 1959, Copper: 55th Report of the State Mineralogist, p. 122.