Even in ancient times, gold was valued as the most expensive metal. People are still interested in how gold deposits can be discovered.
But to do this, you need to know in what form this precious metal is found in nature. Deposits with precious metal reserves may vary depending on the method of formation and the place where the metal was formed. Thus, they are divided into primary (root) and secondary (placers).
Bedrock deposits
Such formations of gold appeared as a result of the movement of magma during a period of volcanic activity. Magma contains much more of this metal than the earth's crust.
Magma, escaping from the depths, gradually solidified, as a result of which minerals were formed. If the elements had increased refractoriness, they crystallized, and low-melting substances moved on. But not only gold has a low melting threshold; there were also other elements, the combination of which formed a chemical complex of substances. Therefore, in the area of primary deposits it is difficult to find gold in its pure form. Typically, compounds where there are gold inclusions consist of a combination of iron, copper, lead and zinc.
Because As a result of volcanic activity, mountains were formed, then gold must be looked for in mountainous gold-bearing areas.
History of the appearance of metal
There are many theories explaining what gold is, where it was formed, and why it ended up in the earth’s crust and the core of the planet. Previously, it was generally accepted that Au in the universe is a consequence of processes in the structure of stars (nucleosynthesis). However, later new assumptions emerged as to where the history of gold originated. So, there is a theory that metal particles are a consequence of the destruction of neutron stars.
Aurum has a significant weight. Even after decay, the particles will fall rapidly. They pass through the atmosphere along with asteroids (as in the late heavy bombardment, at times corresponding to the period 3.8 billion years ago). This is a likely route for the precious metal to enter the planet's crust. We can guess where gold came from on Earth. The dust left behind after the star explodes gradually condenses. In this form it reaches the planet.
If you are wondering where gold comes from in nature, you should consider that a significant proportion of it is contained in the earth's core. The metal got there, again, due to its significant weight. This is one of the main signs that allows you to determine whether an aurum product is original (they are always heavier than many others: made of silver, brass). In addition, other theories are being built about how gold appeared on Earth, but ended up in the core. It is believed that this is the result of exposure to high temperatures when the planet was in a molten state.
Precious metal - gold
However, the theories on the basis of which assumptions are made about where gold came from are not always justified. For example, the version that star dust (gold) falls into outer space and then settles on Earth was struck by the inconsistency of the facts, for example, there is no information that such processes actually develop. Scientists do not yet provide specific data, but make statements that such assumptions (regarding falling gold dust) are indirect. There is not enough information, and it is impossible to confirm the theory due to the peculiarities of the operation of satellite spectroscopes.
Interesting: Aurum is found in the earth's crust, mantle, planetary core, and also in water. It is believed that 1 km2 contains 1 kg of precious metal.
Placer deposits
Secondary type gold reserves arose in the process of various mechanical and chemical impacts on primary type gold deposits.
Gold particles moved from mountainous areas to plains as a result of the following natural phenomena:
- Groundwater movements.
- Wind.
- Rock falls, etc.
Rains and mountain rivers carried mountain rocks closer to their foot. When colliding with boulders and other magma formations, they were crushed, displacing gold particles. Gold is inert in relation to other chemical units, so it settled in its pure form in various bodies of water (rivers, lakes, etc.).
Although the source of gold is the same, there is a significant difference between placer gold deposits and bedrock deposits.
Over millions of years of formation of the earth's surface, it is almost impossible to track the migration of gold deposits.
There are fewer primary placer deposits, but it is easier to detect their locations, because they are visible on the surface. At the same time, they are easier to develop, while searching for and extracting mine gold is a much more labor-intensive process.
Properties and Application
The density of gold is 19.3 g/cm³, the metal melts at a temperature of +1063°C, and the boiling point reaches +2660°C. It is very malleable and plastic. Conducts heat and electric current well. Only silver and copper are superior to gold in this case.
This precious metal is a chemically resistant element. Even if it is heated strongly in air, it will not change its shape. This substance can only be dissolved in aqua regia, chlorine water or solutions of alkali metal cyanides. Mercury can also dissolve gold, forming an amalgam. If the latter contains more than 15% precious metal, then it becomes hard.
To this day, the most expensive jewelry is made from this precious metal, and it is a measure of value.
Because of its softness, gold is often combined with copper or silver. To find out how much gold is contained in the alloy, just look at the sample of the product; it indicates how much of the precious metal is per 1000 g of the alloy. Two samples are accepted as a standard - 583 and 750. Countries involved in gold mining are often among the most developed countries.
Gold Au – aurum (aurum): etymology of the word
The name of the metal aurum is read in Latin as “aurum” (written the same way as it is heard/pronounced). The abbreviated designation is common (the letters are used – Au). It is this option that is used in chemistry when drawing up formulas for substances and compounds. This is an element of the periodic table of Mendeleev, belongs to the 6th period.
The main distinguishing features: yellow color, sound upon impact that is uncharacteristic of other precious metals, softness. If you are wondering how gold is designated in the periodic table, you need to look for element number 79.
The etymology of the word that precious metal is called includes different meanings:
- old Slavic version - based on the word “gold”;
- Lithuanian meaning geltonas – “yellow”;
- The Latin name for gold in translation corresponds to the characteristic color of the precious metal – “yellow”.
Aurum - gold (Au)
In addition, aurum is associated with the sun, so in ancient times the corresponding sign/symbol was used to designate such a metal. Continuing the logical chain, the relationship between the color of Au and the sun is noted. For this reason, in many countries, among the facts about gold one can find the only possible meaning of its name. This color is yellow. Another explanation for this is the Proto-Indo-European root “yellow, green, bright.”
The world's largest gold deposits
The largest gold deposits in the world are listed below:
- Boddington. The mines are located in Australia. Gold and copper are mined in Boddington. Gold mining began in 2009. By 2011, the first million ounces were mined.
- Lihir. The island is Aniolam, the country is Papua New Guinea. The mines have been operating since 1982. In 2010, the gold deposit was purchased by the Australian company Newcrest.
- Peñasquinto. The mine is located in the state of Zacatecas (Mexico) and is owned by Goldcorp (Canada). The quarry is considered the largest in Mexico and the fifth largest in the world.
- Carlin. The quarry is located in Nevada (USA). 75% of the country's total gold and 3% of the yellow metal mined in the entire history of gold mining are mined here. The map of gold mines in the state of Nevada is not limited to two or three deposits, there are a lot of them. Some of the largest are also the Cortez and Goldstrike deposits.
- Yanacocha. North of Peru. The largest deposit in Latin America, with an area of more than 1386 km².
- Pueblo Viejo. The quarry is located in the Dominican Republic, 100 km from the capital of the country, Santo Domingo. After attempts by the government of the Dominican Republic to organize mining of the precious metal to no avail, it was decided to grant these rights in 2012 to the Canadian companies Barrick Gold and Goldcorp.
- Grasberg. Indonesia, a country rich in volcanic rocks, is home to one of the largest gold mining operations in the world. It is there that the largest reserves of gold and the second largest reserves of copper are found.
- Muruntau. Geologists discovered this deposit in 1958 in Uzbekistan in the Kyzyl-Kum desert. The mine started operating in 1967. Turquoise and arsenic are also mined in large quantities in these places.
All these places have the largest reserves of the precious metal on the planet. Although the gold mining map is much more extensive.
Gold mining areas in Russia
As experts noted, there are more than 22,000 tons of this metal in Russian subsoil deposits. On average, 190 tons of gold are mined annually. In terms of the amount of reserves, Russian regions occupy an honorable second place. South Africa is in first place. 11% of the world's gold reserves are located in the Russian Federation. The largest gold deposit is Sukhoi Log, located near Irkutsk. The Sukhoi Log deposit contains approximately 1,900 tons of gold ore. Gold reserves in this area are developed mainly from placer mines. The Sukhoi Log deposit was discovered back in 1961. Since 2017, large companies and Polyus have begun work at the Sukhoi Log mine.
Other deposits include:
- Districts of Eastern Siberia - Yenisei, Prilensky, Bodaibinsky, East Transbaikal.
- In the Yakut region - Verkhoyansk and Aldan districts.
- North-eastern part of the country.
- Amur region.
- Primorsky Krai.
Until recently, Natalka, located in the Magadan region, was considered a large gold deposit. At the moment, work there has been temporarily stopped.
At the beginning of work, when there is still a lot of metal, mining is carried out using the quarry method; in subsequent years, as a result of depletion of reserves, they switch to the underground mining method. For example, at the Sukhoi Log deposit, open-pit gold mining is designed for 50 years.
World gold mining
100-150 years ago, people did not have information about the origin of the gold metal, so mining it became a gamble for them. Today, even a schoolchild will talk about the origin of gold in certain rocks, and therefore its mining has reached an industrial level. Scientists can accurately calculate how many grams of precious metal can be obtained from a particular rock.
To date, 160 thousand tons of gold have been mined, and the bulk of production has occurred in the last 100 years.
Precious metal mining technologies
The ancient and modern history of gold is varied, revealing several methods of Au extraction. In order for it to emerge from the earth’s crust, various manipulations are performed. Aurum is not extracted from large bodies of water - it is unreasonably expensive, and the result is weak. The main sources are surface and deeper layers of soil. To lift the precious metal from the depths and remove impurities, several basic technologies are used.
Sliding (washing) is an ancient method of laundering gold sand.
This method is the best if you need to conduct search work to detect aurum. Based on sampling of small reservoirs (rivers, streams). Particles of the precious metal begin to spread due to the destruction of the rocks of which they became a part. This is facilitated by small bodies of water - rivers, streams. Aurum appears as shiny yellow particles. This is a concentrate, indicating that there is precious metal here. This feature explains why Au is found mainly in the Urals and other northern regions of Russia.
Slice method of gold mining
Amalgamation with mercury
The method is based on the ability of the aurum to respond to exposure to mercury. To obtain precious metal from waste rock, you need to tackle the process thoroughly. To do this, it is necessary to wet the aurum with liquid metal, the result will be interesting - an amalgam is formed, which allows the Au to be dispersed, and later to restore its original shape.
Cyanidation - extraction of gold from ore
The process is called leaching. It must be remembered that aurum is resistant to oxidation at ordinary temperatures. Considering these properties of gold, it is possible to obtain the precious metal from the rock by treating it with cyanide solutions. The metal, free of impurities, is restored to its original properties.
The disadvantage of this method is the possibility of obtaining less precious metal than the rock originally contained. In addition, cyanide is used to work with low-quality ore.
Leading countries in gold production
More recently, the leading positions in the production of the yellow metal were occupied by the regions of South Africa, or rather South Africa. Today everything has changed, and completely different states have emerged as leaders.
The leading positions are occupied by the following countries:
- People's Republic of China - the amount of gold mined is 455 tons.
- Australia - 270 tons.
- In Russia, 250 tons of gold were mined.
- United States of America - 209 tons.
- Canada - 170 tons.
Other countries are only slightly inferior to those mentioned above. Major gold-mining countries also include South Africa, Mexico, Uzbekistan, Indonesia, Peru, Ghana and Brazil.
But gold deposits in deposits tend to run out, and metal reserves are depleted over time (for example, the Natalka gold deposit in Russia). Therefore, in many countries, increasing attention is being paid to geological exploration of new deposits. The world's largest gold mining companies are starting mining in areas previously considered unprofitable. This leads to the fact that technologies for the extraction of this metal are constantly being improved.
Determination of the world value of gold and its status on the stock market
Aurum affects the price of various currencies. On stock exchanges, the price of precious metals is set daily, which allows you to track the slightest changes. However, no one expects strong fluctuations, given that gold has the status of a safe asset, which means that a steady increase in the price of Au is planned. But the cost still fluctuates, which depends on external factors, including: the amount of metal mined, inflation, supply and demand for aurum of various forms (jewelry, bars, coins, etc.).
