Upper Cambrian sedimentary rocks have been pyritized, and a halo of pyritization surrounds the copper deposit. Afon Wen Fault system is located near the deposit and was active after the lower Ordovician volcanics were emplaced. Copper ores occur as thin veinlets and disseminations. The deposit was discovered in the late 1960s by Riofinex Ltd., and drilling indicated at least 200 million tons of reserves carrying more than 0.3% copper. Leaching of copper from the deposit by groundwaters led to the formation of a 70-acre peat deposit so rich with copper that it was profitable to strip the peat, ash it in a stone kiln, and send the ashes for smelting.
Study area name
Mason (n.d.); Rice and Sharp (1976); Shepherd and Allen (1985)
Rice, R., and Sharp, G.J., 1976, Copper mineralisation in the forest of Coed y Brenin, north Wales: Institutions of Mining and Metallurgy Transactions, Section BApplied Earth Science, v. 85, p. Bl13.