Gold. Story. Mining Methods

Gold was probably the first metal of any kind to be explored for or mined by humans, and its exploration began in Mesopotamia around 4000 все. Gold is mostly found pure in nature, but for industrial use it can be joined with other metals, such as copper, nickel, or zinc. The color of gold varies from white to yellow. It is a soft metal, good for heat and electrical conduction, with a high point of fusion and ebullience and flexibility, that is, 1 gram of gold could produce 2.5 kilometers of wire.

It also can be transformed in plates so thin that 150,000 of them would be only 1 centimeter thick. These qualities and its rarity, durability, malleability, and resistance to corrosion give gold a stable and high value. It is commonly used as an investment, as a material to make coins and jewelry, as an electronic compound (because it is a good conductor), and as a reserve for currency.

Gold is used in such products as computers, communications equipment, spacecraft, and jet aircraft engines. It is important to art, jewelry, and industry, but most of all it has a unique status as a long-term store of value. Most of the gold produced every year in the world is stored in the vaults of government treasuries or in central banks, in part to give credibility to currency.

This drawing shows miners in the American west using a "Long Tom" sluice box to separate gold from gravel

Gold is found on the surface of the Earth, in rivers, and in mines. It is formed in the inner parts of the Earth and brought to the surface by water action and carried to rivers as grains. The simplest way to explore for gold is to mine the land surface or explore a riverbed, washing the river sediment in a pan to separate the gold, which remains in the pan because it is heavier.

That simple way was used for many years to explore for the more external deposits of gold. But as external deposits of gold are removed, more sophisticated methods of exploration, such as hydraulic mining, are required. The deepest deposits can be explored in open or subterranean mines, where gold is found in the rock.

From Mesopotamia the exploration for gold spread across Asia and Mediterranean societies, especially Egypt, where gold was used for adornment. Gold is easy to melt, and because its characteristics are immutable it can be melted several times with no loss of quality. The tale of King Midas illustrates how gold was considered a precious metal in antiquity.

Midas was a king in Asia Minor who loved gold above all else. When God decided to grant one of Midas's wishes, Midas asked that everything that he touched would turn to gold. Soon his wish became a nightmare because he could not even feed himself. So Midas begged God to free him from his wish. God told Midas to bathe in the Pactolus River, and he obeyed immediately. The ancient Greeks used the tale of King Midas to explain why gold was mixed in the sand of the Pactolus River.

During the Middle Ages gold was considered by alchemists to be a perfect element because it defies the decay that characterizes life and also because fire purifies it instead of destroying it. Alchemists called gold the "fifth element" because they believed that every life or thing is made of four essential elements—earth, fire, wind, and water.

The search for the philosophers' stone—an imaginary stone, substance, or chemical preparation believed to have the power of transmuting baser metals into gold—was important to the development of medicine, chemistry, and metallurgy.

In the fourteenth century gold was sought because it was used as currency in Europe. The great voyages of discovery allowed the gold of the New World to be brought to the European market. When Europeans reached the New World the Mayas, Aztecs, and Incas already had discovered gold and considered it a precious metal.

The desire of the Spanish for gold was so intense that when Spanish explorer Francisco Pizarro conquered Peru, he arrested the Inca emperor Atahualpa and promised to free him if he could provide enough gold to fill an entire room as tall as the emperor. As soon as the Incas filled the room, Pizarro killed Atahualpa and took the gold.

In Brazil gold was discovered in the eighteenth century in riverbeds in Minas Gerais State. This discovery made Portuguese monarchs, especially King John V, rich. In Minas Gerais a large civilization arose, and many cities, such as Ouro Preto, were built, and many churches were covered with gold.

In the nineteenth century there were gold rushes in Australia and in California in the United States, where in the 1840s John Sutter—a Swiss immigrant— was determined to exploit cattle and agriculture. In 1847 Sutter sent James Marshall and about twenty men to the American River to build a sawmill to provide lumber for his ranch. There Marshall and the other men found gold. News of the discovery spread, and thousands of immigrants rushed to the region to prospect. That gold rush was immortalized in 1925 in English actor Charlie Chaplin's film The Gold Rush.

Today gold is mined mainly in South Africa, Russia, and Canada. In Brazil in 1980 gold was discovered in Serra Pelada in Para State, which now has the largest open mine in the world.