Biologically Assisted Copper Secondary Sulfide Ore Leaching in the Presence of Chloride

Abstract

Mining operations today face a difficult challenge in terms of water availability, with most of these deposits located in arid areas where fresh water is scarce. This is especially relevant for bio-mining operations where not only the source but the water quality can be a decisive factor for its successful utilization. This research evaluates the metallurgical and microbiological performance of an adapted chloride and copper-resistant mixed culture during the leaching (laboratory scale columns) of a secondary copper sulfide at different chloride concentrations. Up to 6 g/l chloride all columns established Eh potentials over 750 mV with complete oxidation of ferrous iron in the PLS showing well established microbial activity. Copper recovery in solution, along with a high redox potential, was established faster in the mesophilic column but leveled off quickly over time. Copper extraction showed that the 6 g/l chloride column has the highest metallurgical performance (83% CuT) with 4 extra points of copper recovery over the 1.5 g/L and 3 g/l Cl- columns. These results are a good indication that comparable copper recovery rates –to the ones achieved using fresh water- can be reached in the presence of important chloride concentrations by way of using the use of a suitable and well adapted microbial population. The related process and chloride-resistant culture have been patented under the following ID N°: EP2313534/US0201095.