Gold Mining and Its Environmental Impacts

Gold is mined because of its unique properties - malleability, elasticity and hardness combined,1 as well as its applications for jewellery.

It is estimated that gold ever mined amounts to around 145 000 tonnes. In 2003, mine production was 2 601 tonnes or 67% of total gold demand in that year2. Total gold supply in 2003 was 3 882 tonnes, which exceeded demand.3
Typical mining costs are US $238/troy ounce (31,1035 g) gold, but these can vary widely depending on mining type and ore quality. Richer ores mined at the surface (open cast mining) are considerably cheaper to mine than underground mining at depth. Such mining requires expensive sinking of shafts deep into the ground.4

Gold applications

The most gold is used for jewellery, up to 90% of the total gold produced5. It is thought, that if gold would be required only in industry, mining could be stopped, as recycling would be sufficient. Recycling currently satisfies around 15 – 20% of the total demand.

The rest of gold is used in industry, and thanks to its excellent heat and electro conductivity, as well as resistance to corrosion it is used virtually everywhere, from semiconductors to space suits.6

Around 35 000 tonnes of gold are located in the national reserves7. After 1960s, when gold price was not fixed to national currencies any more, it has partly lost its significance. Some countries are selling their gold reserves, usually very slowly, in order to influence global gold prices, not more than 50 tonnes per year.

General mining process

After gold mining site is selected, research is done to precisely locate areas of gold ore. Then material containing gold re is being excavated and its contents are detected.
The grade of ore refers to the proportion of gold contained in the ore of a particular mine and is quoted in grams per tonne (g/t). The type of mine depends on the depth and grade of the ore. At a rough estimate, the larger, better quality South African underground operations are around 8 - 10g/t, while the marginal South African underground mines run at around 4 - 6g/t. Many of the operations elsewhere in the world are open pit mines, which run at lower grades, from as little as 0,6g/t up to around…