Gold Extraction Methods

Activity - Ore Crusher Demonstration

Alluvial gold is extracted using a rocker and cradle or simple sluice and various panning techniques. Reef gold is imbedded in quartz rock, which has to be crushed to release the gold caught in the seams.

Ore Treatment

The ore after crushing went through a screen, with the assistance of water and ran over a flat area that was treated with, firstly, copper sheet, cyanide paste and then mercury. Mercury has a chemical affinity with gold, silver and other metals.

As the processed ore runs over this area, the gold attaches itself to the mercury while the rest of the ore passes through to the tailings dump.

Eventually the cyanide, mercury and gold are scraped up and placed in a retort, where the mixture is heated until the cyanide and mercury evaporate off and are recycled, leaving the gold behind.

The cyanide paste acts as a buffer so that scrapings of copper do not contaminate the separated gold.

The extraction is a dirty process, often doing environmental damage and causing lung damage and deafness to the workers, as well as the dangers of mercury and cyanide poisoning.