The Lomas Bayas and Tesoro copper heap-leaching operations in Chile generate leaching solutions with nitrate and chloride concentrations in excess of 20 g/1. However, according to Cognis Corp., typical modified aldoxime copper extractants show a high rate of irreversible degradation with leaching solutions of this type, and within a relatively short period of time the total reagent inventory needs to be replaced.

After extensive research, Cognis has developed ketoxime-based reagents which it says are much more stable when used with high-nitrate leaching solutions. The company's LIX 84-1 system is used at both Lomas Bayas and Tesoro, and, says Cognis, have proven to be a cost-effective copper extractant, allowing high copper recovery from leaching solutions containing up to 7 g/litre Cu at a pH value as low as 1.3.