Production and uses of gold
The size of cube made of all gold ever produced in the world.
Gold mining in one form or another goes back into antiquity at least for more than 4000 years. During the earliest times one can imagine that the winning of gold was a haphazard activity, nuggets of the native metal being plucked from some auriferous stream, the oxidation zones of gold or sulphide deposits or from residuum near such deposits. Production was probably erratic and generally unorganized. By the time of the Pharaohs, however, organized gold mining in the Arabian and Egyptian shields appears to have been well established, and gold was seemingly relatively plentiful compared with silver for in the Code of Menes, the first pharaoh, who reigned in Egypt about 3500 B.C., it was decreed that "one part of gold is equal to two and one-half parts of silver in value". Since that time up to the fall of the Roman Empire gold appears to have been mined almost continuously mainly from placers but also from the oxidized zones of deposits in all organized societies throughout the world. There is evidence of ancient gold workings and placers ranging from Japan, through China, India, Russia, Turkey, the Mediterranean islands and lands, central Europe, Spain, France, Britain, Mexico, Central America and South America. The early Minoan goldsmiths had a source of gold for they produced some of the finest pieces of early gold work known to man. The Greeks mined gold extensively throughout their empire and appear to have prospected for it far and wide judging from the legend of Jason and the Golden Fleece. The Romans, likewise, sought gold throughout their empire obtaining it from placers and mines in Spain, France, Britain, Germany, Central Europe and the Middle East. The yearly production of gold in the Roman Empire at the beginning of our Era can only be roughly estimated; a reasonable figure seems to be about 250 000 oz. One of the great gold placer areas in the Middle East was the river Pactolus in Lydia (a tributary of the present Gediz in Anatolia in Turkey). Another was the Pontic field in Turkey, on the southern shore of the Black Sea, possibly the site of the Garden of Eden and probably one of the sites of the Golden Fleece sought by Jason.
Nearly all of the gold mined by the ancients was wrought into idols, shrines, bowls, vases, flasks, cups and jewellery. Later, about 1000 BC., gold and silver came into general usage for coins as a medium of exchange, certainly in all countries between the Indus and the Nile and probably on a much more widespread geographical basis. By Philip of Macedon's time (356 BC.) gold and silver were generally valued in the ratio of 10:1. This value ratio did not change much through the centuries that followed for we find that in England the ratio in 1464 was 11:1 according to the recorded mint price. Since then there has been considerable fluctuation in the value ratio as shown in Table I. There is an interesting comment in the Engineering and Mining Journal (vol. 95, p. 1163, 1913) with regard to the origin of the ratio of value between gold and silver that merits quotation:
"I have endeavoured to discover as to how and when the ratio of value between gold and silver commenced, and as to what was its origin", said Bedford McNeill, in his presidential address before the Institution of Mining and Metallurgy." Sir David Barbour has called my attention to an interesting theory of Professor D'Arcy Thompson, that the origin of the ratio may have been astronomical, gold being associated with the sun, and silver with the moon; the period of the earth's revolution round the sun being 365 1/4 days, and that of the moon round the earth 27 1/3 days, it will be found that the ratio between these figures is very nearly 13 1/3, and this figure 13 1/3 was the ratio that was fixed between gold and silver during the Babylonian Empire (2000 B.C.) down to the Lydian Empire (500 BC.). Professor D'Arcy Thompson has also pointed out that the Lydians made coins of what was called 'electrum', and reckoned one electrum coin as being of the same value as 10 silver coins of the same weight. It was supposed that the Lydians were unable to separate the gold from the silver, but when we find by assay that the proportions in these old coins of gold to silver were approximately as 73 and 27, calculating gold as 13 1/3 times as valuable as silver, and we find that an electrum coin would be worth exactly 10 silver coins of the same weight, we cannot help but admit that the Lydian assayers must have been well versed in the science and practice of their art, and that such figure cannot be mere coincidences."
Since the earliest times gold has been hoarded by kings, states, popes and individuals, the prime example being Croesus of the Mermnadae, last King of Lydia (560-546 BC.). It is said that most of his fortune in gold came from the placers of the Pactolus, but it seems more likely that his wealth had a more widespread origin since the Lydians were renowned for their trading pursuits. How much gold was hoarded in ancient times is unknown, but the practice seems to have increased at the beginning of our era, so much so that during most of the Dark and Middle Ages both of the precious metals were scarce. Some of the scarcity was undoubtedly due to the exhaustion of most of the placers in Europe and the Middle East and also to a general decline in mining, the economic limits, in terms of depth, of profitable ore having been reached in many districts mainly because of engineering problems (ventilation and flooding by ground water). It is estimated that the total annual production of gold during the Dark and Middle Ages probably averaged only about 100 000 oz.
Geographical exploration brought an abrupt change in this situation, the manifestations of which affect us to this day. With the rediscovery of America by the Spaniards in 1492 came the discovery of great stores of both gold and silver first in the islands of the West Indies, then in Mexico and finally in Central and South America. At first, great quantities of gold were looted from the natives, but as this source declined active placering and mining by slave labour provided a large and continuous influx of gold and silver to Spain.
Despite an attempt by the Spanish government to keep the precious metals to itself, they soon filtered over the whole of Europe, increasing the supply of money and inflating prices. It is estimated that from 1492 to 1600 more than 10 million oz of gold came from the Spanish Americas, which was about 40 per cent of the world production at that time. Marked increases in gold production from South America, particularly from the placers of Colombia, were registered during the period 1600-1800; for example some 48 million oz were won during the 18th century, accounting for about 80 per cent of the world production. Two further increases in the world gold production followed during the periods 1820-1880 and 1890- 1920. The first marked the discoveries of the great placer and lode mining areas of Siberia, California, Australia and New Zealand; the second followed the discoveries of placers and bedrock deposits in Alaska, Yukon, Central Canada and on the Witwatersrand of South Africa. Since 1920 there has been only one period, 1933-1939, when the production of gold increased significantly. During and since World War II a general decline in the production of gold in nearly all countries except South Africa and the Soviet Union has taken place. In South Africa the average annual production for the last 5 years (1970-75) has been about 27.5 million oz; during the same time in the Soviet Union the annual production for the last 5 years has probably averaged 10 million oz, although this figure is only a rough estimate, the true value being a closed guarded secret. It is estimated that the total amount of gold won by man from the earth to 1975 is about 3 billion (3 X 109) oz. Of this amount some 2 per cent was produced prior to 1492; 8 per cent during the period 1492-1800; 25 per cent during the interval 1801-1900; and 65 per cent from 1901-1975, all figures being rough estimates.
Approximately 88 per cent of the annual world production of gold is obtained from primary deposits and placers (fossil and modern) mined essentially for gold, The remaining 12 per cent comes as a by-product of base metal and silver mining. The average annual world production during the period 1971-1975 inclusive was about 49 million oz. The principal producing countries are shown in Table II.
Rafal Swiecki, geological engineer email contact
This document is in the public domain.