Unrefined gold, known as doré, being cast into bars at the Kopanang mine’s metallurgical plant.

Picture by K.Schoemaker, courtesy of the South African Minerals Council

At many large gold mines, the final stage of production, prior to the gold being sent to a refinery, is the doré pour, as shown here.

Doré is the term used for the rough or unrefined gold produced in the mine’s metallurgical plant. Its composition varies greatly depending on the mineralogy of the ore body and the type of processing plant. In most South African mines, for instance, the doré contains around 10% silver and minor amounts of base metals. Regardless of the chemical processes used to extract the gold from the ore, once it has been turned into metallic form, the gold needs to be cast into bars to facilitate security, transport and measurement of the gold content.

The picture shows a typical set-up of a doré pour. The reason for the cascading arrangement is to allow the slag floating on the surface of the molten metal to be removed before the doré is cast into rough (i.e., unrefined) bars.