Mining Cyanide Leaching. Gold is dissolved by the cyanide and then removed from the heap or columns. It is then extracted from the pregnant leach solution by adsorption on carbon or resins. This cost effective, proven method of ore extraction provides maximum recovery for many gold ores, including low grade and some refractory ores.
Small batch cyanidation leaching may be used to obtain all bullion products. Jig removes coarse gold ahead of cyanidation, improves recoveries, eliminates erratic tailings. Combination flotation and cyanidation permits milling both oxides and sulphides. Leaching for gold of a flotation concentrates to produce all bullion.
Gold occurs in ores in many different forms and the scheme of treatment has to be worked out accordingly. Fine, free and clean gold presents no problem provided that the cyanide solution contains no detrimental impurities. Coarse gold is usually removed ahead of cyanidation by gold traps, blankets or other standard methods and is treated separately.
Flotation will frequently be used when gold is recovered in conjunction with other metals such as copper, lead, or zinc. Flotation concentrates are usually sent to an off site smelting facility for recovery of gold and base metals. Cyanide leaching is frequently used in conjunction with flotation.