Exploration geological and hydrometallurgical applications of Cu isotope fractionation: Examples from porphyry copper deposits in the Southwestern US

Cu isotope fractionation in low temperature aqueous environments has been well documented. Here we apply Cu isotopes to two distinct, yet related mining problems. First, an exploration geological application where we measured copper isotope fractionation in oxidized leach caps, chalcocite enrichment blankets and hypogene mineralization in 4 porphyry copper deposits located in South western USA. Cu isotope patterns exist in the lateral and vertical distribution within the mines coupled with distinct relationships with Cu grade. Second, a hydrometallurgical application where we measured the leach fluids, feed and residues from a quick leach text of Cañariaco ores. The results indicate the relative proportions of the minerals providing Cu during leaching. Interpretations of the QLT test measurements indicate covellite is the dominant ore mineral providing Cu during leaching. Both applications clearly demonstrate the power and ability of using the Cu isotope technique to understand low temperature aqueous processed involving copper.