Geothermal energy for the increased recovery of copper by flotation enhancement

The possible use of geothermal energy (a) to speed the recovery of copper from ore flotation and/or leaching of flotation tailings and (b) to utilize geothermal brines to replace valuable fresh water in copper flotation operations was evaluated. Geothermal energy could be used to enhance copper and molybdenum recovery in mineral flotation by increasing the kinetics of the flotation process. In another approach, geothermal energy could be used to heat the leaching solution which might permit greater copper recovery using the same residence time in a tailings leach facility. Since there is no restriction on the temperature of the leaching fluid, revenues generated from the additional copper recovered would be greater for tailings leach operations than for other types of leach operations (for example, dump leaching operation) for which temperature restrictions exist. The estimated increase in total revenues resulting from two percent increase copper recovery in a 50,000 tons ore/day plant was estimated to be over $2,000,000 annually. It would require an estimated geothermal investment of about $2,130,000 for a geothermal well and pumping system. Thus, the capital investment would be paid out in about one year. Furthermore, considerable savings of fresh waters and process equipment are possible if the geothermal waters can be used directly in the mine-mill operations, which is believed to be practical.