For the first time, copper isotopes (expressed as δ65Cu) wer used as indicators of reactions occurring during the Cu-ore heap leaching, an in situ technological process used for extraction of this strategic metal. In comparison with unleached ore (average δ65Cu -1.47‰), leached ores exhibit lighter isotopic values (average δ65Cu -6.01‰) and enrichment of the leachate in heavier 65Cu isotope indicating a dissolution of primary Cu-bearing minerals along with an oxidation process. Our results, based on combined measurements of Cu isotopes and mineralogical investigation with geochemical modelling, can be used as analogy of Cu leaching in gossans.
Sracek O., Ettler V., Mihaljevič M., Kříbek B., Mapani B., Penížek V., Zádorová T., Vaněk A. (2024): Identification of processes in Cu-ore heap leaching using Cu isotopes and leachate chemistry at Tschudi mine, northern Namibia. Hydrometallurgy 228, 106356. (DOI)