Cyanidation is not used to extract large size gold nuggets from ore because the process is deemed too slow and is not cost effective. In mining operations that contain larger, free-milling type gold deposits, stamping and traditional gravity separation methods are more effective. Cyanide is used to extract gold from ore where it is spread throughout the ore in fine amounts.It is well-known that the introduction of more oxygen speeds up the leaching process but it is not often done in a mill out of cost concerns. Different elements in the ore itself can wreak havoc on the process and significantly hurt the effectiveness of the process. The ore that is left over after grinding, milling or gravity separation is commonly known as a ‘heap’.There are two common ways that the heap is Processed,This process which is also known as ‘vat leaching’ most often takes place in a specialized mill that is located on the mining premises. This process works by exposing the surface of the finely crushed ore to the cyanide salt solution. Once exposed to the gold, the solution binds with ions in the gold that allows them to separate out into solution and then be screened for collection. https://www.prominetech.com/