Practically all the
gold in the world is mined.  To
produce one troy ounce (31.1035gms) of gold from a rich mine, about three
tonnes of ore are blasted from the reefs, conveyed to the shaft, hoisted
to the surface, crushed to the consistency of powder and then passed through
the processes of agitation. It then passes through filtration, and
treatment with potassium cyanide ( KCN a white poisonous granular soluble
solid substance, much used in the jewellery trade) to separate the metal.  The production of this small amount of gold requires more than 5000 litres (5 tonnes in weight) of water, 750 KWh (approx £50 in the UK at 6.5p per unit but industrially the figure is significantly less) of electricity, explosives, chemicals, compressed air and 39 man hours. |
