Processing Ore

Winning the Metals
Digging ore from the earth is only half the battle. The processing of the ore is often just as challenging and expensive, which takes place in refineries, smelters and mills.

While the inside of a mill seems to be a very baffling maze of tanks, pipes, pumps, conveyors, motors, chemicals, pulps and solutions to the visitor, this seeming confusion is actually a carefully designed system constructed for only one objective and purpose - to recover the valuable minerals which are locked up in the ore.

The end product from a mill is called a concentrate, or a doré bar of the metal itself in the case of gold and silver.

All milling and concentrating processes begin with a grinding and crushing stage, which most of the time represents most of the total cost of processing the ore.

Ore minerals are generally found within and among grains of other minerals of ore or relatively gangue minerals which are worthless. This fact makes the processing of some ores more complicated than others.

For example, to the metallurgical engineer, a complex sulphide ore containing microscopic particles of sphalerite within small blebs of galena or other sulphides presents a special challenge, in other words, to design a milling process that will liberate these different constituents from each other as economically and cleanly as possible so that each may be recovered.