| Popis: |
This report reviews mineral recovery techniques practiced at active mines throughout Nevada and determines those that may be enhanced by the application of geothermal heat energy from a nearby resource. Of the thirty-two active precious metal mines identified, ten have hot water on or near the property and could potentially benefit. A second purpose was to collect ore samples and geothermal fluids, determine if they are compatible in the hydrometallurgical process, and carry out laboratory tests to determine the effects of heating on recovery rates. In addition, interfering or counterproductive factors were also identified. The laboratory work consisted of measuring the effects of thermally enhancing two hydrometallurgical processes; cyanide heap-leaching of gold and silver ores and bacterial leaching of sulfide rich gold ores. Thermally enhanced cyanide heap-leaching of gold and silver ores produced increases in extraction ranging from 8 to 20% for gold and 17 to 40% for silver. The temperature required for these increases is 35/sup 0/C to 40/sup 0/C, well within the range of available geothermal resources. |
