DEMONSTRATION OF GEOCOAT~(TM) HEAP BIOOXIDATION PROCESS AT THE TRES AMIGOS MINE

摘要

A concentrate biooxidation process was successfully demonstrated in the field in a remote part of northwestern Mexico. A 275 tonne (300 st) biooxidation heap was constructed using GeoBiotics' proprietary GEOCOAT~(TM) coated concentrate process. The pyrite/chalcopyrite/sphalerite concentrate was biooxidized in the heap for 60 days. Cyanide leach recover of the concentrate increased from 68 percent gold recovery at a cyanide consumption of 1.6 kg NaCN/g Au (110 lbs/oz) in the as-received concentrate, to 94 percent gold recovery at a cyanide consumption of 0.37 kg NaCN/g Au (27 lbs/oz) in the biooxidized concentrate. The heap was constructed at a rate of 7 tonnes (7.5 st) concentrate per hour, using typical heap leach equipment and easily scalable methods. Heap operations demonstrated that energy dissipation in the humid summer environment was easily controlled by low pressure aeration and management of solution chemistry and application. Observations of the demonstration heap appear to support the presence of reflux of moisture within the biooxidation heap.