oxidized gold ore leching mineral processing operation
Figure 1 depicts a flowsheet for processing free-milling oxidized gold ore. The kinetics of gold leaching is slow, and gold ores are frequently ground to less than about 75 μm before leaching. Even then, one day is usually required in the leaching step. In this process, run-of-mine ore is crushed and ground. The ball mill discharge in subjected to gravity concentration to recover the larger particles of free gold. The tailings from this operation are thickened, and the underflow from the thickeners is then subjected to cyanide leaching. In some instances, ores may contain oxygen-consuming minerals, such as pyrrhotite and marcasite, and a preaeration step may be conducted ahead of cyanide leaching. Fig1.Flowsheet options for grinding and agitated leaching of free-milling oxidized gold ores Heap leaching has revolutionized the gold mining industry. Low-grade oxidized ores containing approximately 0.03 oz gold per short ton of ore can be processed with this technology, whereas...