In the last 6,000 years a little over 125,000 tonnes of gold has been mined. But this history is clearly divided into two eras: before and after the California gold rush of 1848. Some calculations suggest that up until then scarcely 10,000 tonnes of gold had been excavated since the beginning of time. Thus more than 90% of the world's gold has been produced since 1848
Early gold mining by the Egyptians, from around 2000 BC, (in the areas which are now Egypt, the Sudan and Saudi Arabia), is thought to have produced no more than 1 tonne annually. Perhaps 5 -10 were produced during the time of the Roman Empire, (mainly from Spain, Portugal and Africa), but in the Dark and Middle Ages (500 - 1400 AD) production, from the mountains of central Europe, probably fell back to less than a tonne. Throughout all this time gold was also being mined and worked in South America, where the goldsmith's art reached very high standards.
From the middle of the 15th century the Gold Coast of West Africa (now known as Ghana) became an important source of gold, providing perhaps 5-8 tonnes per year. In the early 16th century the Spanish conquests of Mexico and Peru opened up a further source of gold. By the close of the 17th century, 10-12 tonnes a year were provided by the Gold Coast and South America together. Gold was first discovered in Brazil in the mid - 16th century but the significant output did not emerge until the early 18th century, considerable supplies began to come from Russia as well, and annual world production was up to 25 tonnes. By 1847, the year before the Californian gold rush, Russian output accounted for 30-35 tonnes of the world total of about 75 tonnes. The gold rushes, and later the South African discoveries, radically altered the picture but Russian production continued to rise, reaching around 60 tonnes in 1914.
The crucial turning point in the history of the gold mining industry came with the discovery at Sutter's Mill on the American River in January 1848, which ushered in a new age of gold. Gold mining now took on a quite different dimension. Output from California soared, reaching 77 tonnes in 1851 and peaked in 1853 at 93 tonnes. That same year gold was also discovered in Australia. The Australian find triggered a gold rush there which reached a climax in 1856 with 95 tonnes. World production at this time climbed to 280 tonnes in 1852 and thence to almost 300 tonnes as Australia flourished.
Production was lifted on to an even higher plane in 1886 with the discovery of the huge gold reefs in the Witwatersrand Basin of South Africa. Gold had first been found in eastern Transvaal in 1873, but the outset it was obvious that the Witwatersrand deposits were of a completely different order. South Africa ousted the United States as the world's premier producer in 1898, a position it has held almost continuously ever since. From 1884, the first year of recorded output, South Africa has been the source of close to 40% of all the gold ever produced. The most productive year was 1970 when over 1,000 tonnes were mined, representing more than three-quarters of western world output.
While the South African gold mining industry was taking off, two further gold rushes occurred. In 1893 gold was found at Kalgoorlie in Western Australia, since when over 1,300 tonnes have been extracted from Kalgoorlies's "Golden Mile “alone. Australian output peaked in 1903 at 119 tonnes, a level not reached again until 1988. And in 1896, alluvial deposits were found in the Yukon territories of Canada, initiating the Klondike gold rush which yielded 75 tonnes over the next three years. By the turn of the century, world production was averaging 400 tonnes annually.
Through much of the twentieth century the gold mining industry was in decline in many countries. There was a brief revival after the rise in the price of gold in the late 1930's; in 1940 United States production was 155 tonnes and the following year, Canadian output reached 172 tonnes, a record which stood until 1991.
However, it was not until the dramatic price rise of 1980 that the industry experienced another transformation. Old mines were revived and exploration activity exploded.
Western world production almost doubled during the 1980s, rising from 962 tonnes in 1980 to around 1,744 tonnes ten years later. A new era of gold rushes occurred, with prospectors swarming to alluvial deposits in various countries including Brazil, Venezuela and the Philippines. Serra Pelada in Brazil proved to be one of the richest placer deposits ever found, yielding 13 tonnes in 1983 alone.
The application of new technologies to the mining, milling and recovery processes also contributed to the boom. They enabled the development of ore bodies that would previously have been considered uneconomic, notably in Nevada, USA, which accounted for over 60% of US production and Western Australia in the late 1980s.
Canadian output tripled in the years following the gold price rise, from 51.6 tonnes in 1980 to peak at 175.3 tonnes in 1991. The industry there is more traditional with underground operations rather than open pits. The most significant new discovery was the Hemlo field in northern Ontario whose three mines produce nearly 35 tonnes annually.
The potential for the development of future mines is promising, particularly low-grade epithermal deposits on the Pacific "rim of fire", in the greenstone belt of South America, in the sub-Saharan Africa (especially Ghana) and in such CIS republics as Kazakhstan and Uzbekistan. Although the industry faced major challenges in the early 1990s, with a lower gold price and tighter environmental controls, improved prices after 1993 provided new incentives. The period of rapid growth is over, but, with less South African output, world-wide production is expected to remain fairly stable.