If we make all the gold ever produced into a thin wire of 5 microns (millionths of a metre) diameter - the finest one can draw a gold wire, then all the gold would stretch around the circumference of the world an astounding 72 million times approximately!

The gold-containing ore has to be dug from the surface or blasted from the rock face underground. This is then hauled to the surface and milled to release the gold. The gold is then separated from the rock (gangue) by techniques such as flotation, smelted to a gold-rich doré and cast into bars. These are then refined to gold bars by the Miller chlorination process to a purity of 99.5%. If higher purity is needed or platinum group metal contaminants are present, this gold is further refined by the Wohlwill electrlytic process to 99.9% purity. Mine tailings containing low amounts of gold may be treated with cyanide to dissolve the gold and this is then extracted by the carbon in pulp technique before smelting and refining.

All metal atoms are made of the same building blocks of protons, neutrons and electrons, but in different quantities, so in theory it could be possible to change base metals into gold or any other metal of value to mankind. In practice, it is achieved only in nuclear reactions, where heavy radioactive metals decay into other lighter elements, including some isotopes of gold. However, man's ancient dream of turning base metals into gold is not a practical proposition. So it remains a dream!

In 2001, mine production amounted to 2,604 tonnes, or 67% of total gold demand in that year. Gold production has been growing for years, but the real acceleration took place after the late 1970s, when output was in the region of 1,500tpa. This year’s output will fall short of production levels in 2001. This is partly for specific operational reasons at some of the larger mines (Grasberg and Porgera), along with lower grades at some of the operations in Nevada. The reduction in exploration and development expenditure over the past five years is leading a number of analysts to suggest that, with other operations nearing the end of their lives, global production is likely to drop slightly over the next two to three years – subject always of course to price.

This stems back to ancient times in the Mediterranean /Middle East, when a carat became used as a measure of the purity of gold alloys (see next Question 5). The purity of gold is now measured also in terms if fineness, i.e parts per thousand. Thus 18 carats is 18/24th of 1000 parts = 750 fineness.