Gold Vat Leaching OR Flooded Heap Leach

Heap or dump leaching can be applied to ores where gold occurs in a form that can be al least partially liberated without grinding. The process is performed on run-of-mine or crushed ore, and is most suitable for treatment of permeable ore types, although agglomeration processes have been developed to improve the performance with less permeable ores.

Vat leaching is essentially a flooded heap leach with the solution and the ore contained within a vessel or other suitable impermeable impoundment. Its application is limited to the leaching of unusual materials that no respond well to heap or dump leaching but do not require grinding for gold liberation, for example low grade oxide/free milling ores with most the gold present as coarse particles. This is a rarely used process option because of the generally superior economics of heap and agitated leaching systems.

Applications of VAT Leaching

Some aspects must be considered when there is a potential application of Vat leaching. Some of them are mentioned below.

• Ore source. Gold deposits and old tailings with an interesting amount of precious metals.
• Mine location. Have influence in the leaching process.

1. Tropical zones. Where intense rains or excess of water affect efficiency of cyanide solution.
2. Dry zones. Where there is not enough water and is necessary a good control of the water to be used in the extraction process.
3. Cold zones. Where low temperatures make difficult the human work.

Characteristics of the ore to be treated. Many times there are gold ores that don’t have good porosity and its treatment by heap leaching is not very efficient.

TYPES OF VAT LEACHING.