Extraction of precious stones. Natural stone: types, mining technology, deposits

At the initial stage of its formation, our planet consisted of rocks, water, fire, and was formed among the roar of volcanoes, sparkling lightning and constant collisions of lithospheric plates with each other. The mountains, crawling on top of each other, destroyed, crumbled and mercilessly maimed each other, as a result of which small and big stones broke off from young rocks and rolled down, destroying everything in its path.

Over time, the planet began to slowly calm down, but the process of crushing rocks has not yet been completed: the earth periodically trembles, crushing rocks and grinding them into small and large stones.

Natural stones are called solid pieces of rocks that have appeared as a result of crushing. In their structure, texture and composition, they are very different from each other, and therefore there are extremely many types of them: marble, granite, limestone, as well as shale, shell rock, basalt.

Some of them were formed on land, others - under the influence of fresh or sea water. For example, some blocks were formed thanks to molluscs, which, dying, sank to the bottom, covering it with shells and shells. Over time, the layer became thicker, denser, and after some time collapsed, unable to withstand its own weight, as a result of which the shell particles mixed and formed lumps.

Natural stones are the remains of:

Destroyed sedimentary rocks (75%), which were formed as a result of various erosive processes, primarily weathering and destruction of rocks, mechanical or physical sedimentation from water, vital activity of organisms. Among the most famous names stones - limestone (natural stone white color, consisting of calcium carbonate), sandstone (consisting of quartz particles) and marble - a natural stone that appeared during the transformation of limestone and dolomite;
Metamorphic rocks (about 20%) - igneous and sedimentary rocks that were formed inside the planet and changed under the influence of various physico-chemical processes, primarily the pressure of aqueous and gas solutions and high temperature. The best-known natural stone of this type is quartzite, which is composed of mica and quartz;
Igneous rocks that were thrown out by volcanoes from the bowels of the Earth. by the most famous view Granite is one of the hardest, most durable and dense rocks. The color of this stone is extremely diverse: gray, red, brown, green.

Mining process

Natural stone is mined everywhere and on all continents. Usually, transportation is not cheap (the cost is influenced not only by the quality of the rock, but also by the method of extraction and transportation costs: when extracting the stones of the Earth, it is very important to preserve the appearance of the rock).

Since natural stones have different strength and hardness, they are used for mining. different methods and equipment.

To do this, the deposit is opened, creating a vertical shaft leading inside the quarry. Many countries use the drilling and blasting method and the air cushion method: with the help of drills they make a hole, lay a charge or pump air.

As a result, the rock breaks into pieces (although these methods are cheap, the valuable properties of the rock are lost, because it is highly crushed, which leads to significant losses of raw materials). More expensive though effective method is stone-cutting: it allows you to extract natural stone without much loss.

Dimensions

Natural stones come in different sizes: the most big Stone- this is a rock (formed after a mountain that has big number cracks), followed by blocks, blocks, monoliths and smaller stones. Those that are used in construction can be both small in size and be real giants: a large stone often has dimensions exceeding 10 cubic meters (these monoliths are especially valuable due to the difficulty of extraction and transportation). Large stones that do not have cracks are divided into:

Blocks are big stones rectangular shape, the size of which exceeds ten cubic meters, they are used when laying foundations, cyclopean masonry, in monumental monuments;
Monumental - from 5 to 10 m3, monuments, sculptures, ceilings are made from it;
Unique - size 2x1x1.5 m, monuments, sculptures, columns are created from it;
Piece - the size exceeds 1 m3, they make quadruples, sculptures, vases, bowls, as well as blocks, cobblestones, curb natural stone.

The classification by size does not end there, for example, the height of boulders is from 20 cm to 10 m, crushed stone is from 5 to 15 cm, pebbles are from 1 to 10 cm, and thin plates are considered the smallest (they are used for facing, in mosaics and stained-glass windows) - from 1 to 10 mm.

rock hardness

One more important characteristic stone natural materials are such properties as their strength and durability, that is, the ability to maintain their qualities regardless of external influence. According to this indicator, natural stones are divided into:

Highly durable - begin to collapse after six hundred years, they include quartzites and fine-grained granites;
Durable - begin to crumble after two centuries (coarse-grained granites);
Relatively durable - destruction begins after a hundred years ( white marble, dense limestone, dolomites);
Short-lived - they begin to crumble after a quarter of a century (colored marble, porous limestone, gypsum).

When characterizing the rock, its structure is also taken into account: the size and shape of mineral grains, the degree of crystallization, granularity (how evenly the mineral grains are distributed and whether there are voids). For example, in order to find out which stone is more durable, just look at its components: a fine-grained structure is stronger than rocks with large grains or an uneven structure.

A large stone, the granular structure of which is uneven, is poorly resistant to environmental influences: different grain sizes of minerals when changing temperature regime expand in different ways, which causes large stones to crack, and if water gets into the cracks, natural stones continue to collapse.

Facing materials

If in former times a large stone was often used to build grandiose, durable structures (for example, pyramids), now it is more used as a facing material, decorating palaces, temples, estates, ordinary houses: natural stone is wear-resistant, resistant to frost and practically does not absorb water.

Naturally, such a natural stone should be well processed, taking desired shape, and should also be beautiful (for this reason, not every type is suitable for cladding).

In this case, an important role is played by such properties of stones as the pattern, texture and color of the stone. It is worth noting that each piece has a unique pattern, and therefore in nature there are hardly two identical blocks. This happened because they are different combinations and mixtures of crystalline mineral grains of different composition, up to inclusions of organic and inorganic residues.

In order to achieve desired type, facing materials amenable to processing (the method of processing depends on the grain size and color). Facing stone is an expensive material due to the fact that all its properties must be preserved during the extraction process, therefore, the costs of both extraction and processing are considerable (and this despite the fact that the facing natural stone is not deep).

It is mined carefully, in blocks, doing everything possible so that cracks do not appear. When mining, the most expensive method is used: the rock is cut with stone-cutting machines or, if it is very easily destroyed, the thermal jet method is used, cutting blocks out of the massif using thermal cutters, after which they are given the desired shape.

I love natural stones, mineralogy and the very atmosphere of the places where they are mined.

At the slightest opportunity, I try to visit the deposits drago valuable minerals in any country in the world.

But, surprisingly, today the technology of their extraction has remained the same as it was 200 years ago.

It's heavy risky manual labor. Every day, workers descend underground, fill baskets with rock in the dark, and then bring them to the surface.

Precious stones are found in primary deposits and placers.

Most deposits precious stones located in Brazil, Russia, Sri Lanka, African countries, Colombia, Australia. For the extraction of jewelry stones are used various ways: collection of raw stones located directly on the surface (agate, rhinestone, almandines); chipping off crystals grown on the rock with a hammer and chisel, pick, crowbar, pneumatic jackhammers; explosive way.

This is what a ruby looks like in bedrock, the main task is to extract it without damaging it.

Most often, precious stones are mined from alluvial deposits, as it is cheaper and the safety of raw materials for cutting is higher. This is due to the fact that it is not necessary to destroy bedrock in order to extract precious crystals in an explosive way.
Nature has already done this for millions of years.

Placers- accumulations of precious stones in loose deposits formed due to the destruction of primary deposits.

Primary or primary gemstone deposits occurred mainly as a result of the crystallization of minerals from hot aqueous solutions formed during the solidification of magma.

This is how the layout of the placer of precious stones looks like. On the layout, you can see that the layer that contains the gems is covered with deposits of sand and clay on top. The height of this layer can reach tens of meters. Therefore, when the placer is deep from the surface, it is necessary to drill pits or shafts. Horizontal underground workings run from the bottom of the mine along a layer of sands carrying jewelry raw materials. In the largest production shafts, temporary fastening is installed.

I photographed the display stand at the mineralogical museum in Ratnapura.
This is the section of the mine, the workers in the mine and the fastening of the mine.

Sometimes, to extract stones in the jungles of Thailand, they dig deep holes, and with the help of a device, such as a bag, they pull out soil from this hole, with the hope of finding sapphires and rubies in it.

It is relatively easy to extract jewelry stones from young placers. When mining, it is only necessary to remove the overburden.

Here's how the daily mining goes:
1. In the morning at such a mine, with the help of pumps, they pump out groundwater that has accumulated overnight.
2. Then, 2-3 hours at the bottom of the mine, a useful rock is selected, poured into baskets and raised to the surface.
3. Then this breed is washed, hoping to find jewelry.
4. If you are lucky to find something worthwhile, they go to the main street of the city with the morning loot and try to sell these raw stones.

This is what is left after washing the mined rock. This basket contains amethysts, aquamarines, and spinels.

Sometimes gems are mined directly from the river bed. To do this, the river is artificially dammed in some places so that its waters flow faster. Workers, standing waist-deep in water, stir up the bottom soil with long poles and rakes. The clayey-sandy components of the soil, which have a lower density, are carried away by the current of water, while the heavier gems remain at the bottom of the basket.

Then the colored pebbles are manually selected from the baskets.

In some countries it is practiced hydraulic way placer mining, when loose detrital material is washed off slopes by strong water jets.

Fall in love with colored stones, because the study of precious stones is an aristocratic occupation.
Nona Dronova

How are stones mined?

Natural stone is a common construction material characterized by strength, durability and natural beauty. His prey is profitable business, especially in areas with open outcrops of stone conglomerates. There are many such places on the planet, they are easy to find, it is enough for geologists to study the surrounding relief and geological sections to make a conclusion about the presence of an industrial-scale deposit.

Stone is mined not only in the mountains and on the hills, stone layers also occur on the plains. In fact, the stone is solid rocks, which alternate with soft sedimentary, for example, sand and clay. There are also solid sedimentary rocks, the most common of which are limestone, shell rock, sandstone. The use of stone is construction, architecture, sculptural products, and the creation of decorative items.

Types of stone and their characteristics

It is necessary to distinguish stones that are considered minerals, they include a whole group of minerals with different parameters of strength, abrasiveness and other finishing characteristics:

asbestos - a fibrous mineral that has the properties of a stone in a compressed form;
travertine, which experts consider an intermediate phase between limestone and marble;
gypsum (alabaster) - used not only for sculptures, but also for the construction of houses;
mica - natural flexible glass of different transparency and color;
marble, quartzite, diabase, silicon, characterized by a beautiful texture and used in various industries National economy.

Related materials:

How is gold mined?

Other group natural stones is a rock, that is, conglomerates consisting of several minerals. They can be grouped by category of origin. Stones of volcanic formation, that is, born during the eruption of volcanoes under enormous pressure and impact maximum temperatures. They are characterized by high strength parameters, on the cut they have beautiful drawing And multi-colored blotches. Popular among them are granite used for the construction of buildings, gabbro, from which door handles, sculptures, gneiss, which is a granite with striped veins.

stones igneous origin, that is, representing solidified magma. These are pumice with air bubbles, granular and very durable diorite, basalt, which is considered a solid base under the surface layers of the earth's crust.

Large and important groups of minerals in many activities include precious stones or gems. Groups of such stones today do not have clear distinctions and accepted common names, therefore the concept of gems is very vague and can be applied to many stones, minerals or rocks that can be used in the manufacture jewelry or in other industries. Nevertheless, gems are classified into precious, semi-precious and ornamental minerals and rocks. All of them are transparent and colored and have such qualities as:

great strength
transparency
unusual color (drawing)
radiance and brilliance
high light scattering
the possibility of cutting, grinding and polishing.

Transparent minerals are used mainly for cutting, while colored stones are used for various decorations and in jewelry. And, of course, all gem minerals are valued for their beauty, rarity and durability.

Stone extraction methods

Gemstones have been mined since time immemorial. We can safely say that the first mining occurred at the moment when a pebble of unusual shape or beauty was found on the ground, on the sea coast or in the mountains.

At the moment, all stones are carefully studied: rocks are determined, their origin and composition are analyzed. Then the found deposits are explored, wells are drilled and special samples. Sometimes the deposit is still being explored, and mining is already underway. However, the found deposits become explored only when it is possible to determine how many gems can be mined.

How to carry out the extraction of jewelry is determined depending on their location. Quite rarely, but it happens that deep veins of stone are located directly in the parent rock, and here mining is, of course, difficult. But basically the location of gems is placers. They come across empty nodules, inside of which are crystals called geodes. They look like an ordinary boulder, but if you open it, you can find unusual sparkling crystals: purple amethysts, yellow citrines and other minerals. But such stones as opals, chalcedony or agate can be in gas bubbles formed from basalt and andesitic lava. Affects the mother breed environment, weathering, erosion, as a result of this, an accumulation of minerals occurs, the so-called eluvial placer, or stones with the help of rain streams end up in rivers (alluvial placer) or belong to the seas (coastal-marine placer). For example, on the island of Sri Lanka, such precious stones as sapphires, rubies and spinels were found in pebble placers. And on the coastal-ocean placers, which are located in the western part of Africa, diamonds were found, which are extracted by washing several tons of coastal sand. Almost the same situation is with amber, which is rich in the Baltic coast. After all, gems, unlike minerals, are more dense and the process of settling in them occurs faster as soon as the flow carrying them is weakened.

This so-called "natural alluvium" gives good deposits, sometimes just ordinary primitive soil washing is enough. But, it is worth noting that such placers of stones usually contain not very high-quality samples, because in the process of such a journey, all kinds of damage or crushing into small parts occur. Therefore, in order to extract valuable minerals, one has to get to primary deposits by crushing hard rock. This is hard, long and costly work, because you need to get rid of low-quality raw materials, including waste rock. And the cost of gems with such extraction is higher.

Currently, diamonds are mined using kimberlite pipes - these are tubular bodies with different sizes formed as a result of gas breakthrough. There are more than one and a half thousand such pipes, but less than a dozen are used for industrial production. As a rule, clusters come across not large, mostly single crystals. The largest find was discovered in South Africa, the weight of the Cullinan diamond was just over three thousand carats. Russian diamonds are mainly of Yakut origin, only a small part was found near Arkhangelsk. But the use of kimberlite pipes is no longer possible everywhere, in some places it is necessary to use underground mining, which is very expensive.

For the extraction of gem minerals, you can use underground work (mining) or open methods (quarry). It was mentioned above that distinctive feature underground work is their high price, so this method is used for exact definition mineral body saturated with gems. Basically, these are, of course, diamonds, the real price of which will be able to recoup the necessary costs.

It is worth noting that in many countries, this applies primarily to Africa and Asia, they mainly use primitive mining methods. As a rule, they simply collect gems with various surfaces earth. With the help of damming of rivers, soil is washed. It should be noted that there is a loss of such gems as beryl, tourmaline or quartz. Minerals with a density of less than three units of the Mohs scale are also extracted from placers, which can be located both inside and outside the surface of the earth. When covering the placer with soil, it is removed or somehow opened with mechanically or just by hand. So, for example, celestite gem was mined by amateur enthusiasts in Turkmenistan, which is now an almost abandoned deposit. And on the Kola Peninsula near the Keiva mountain range, the largest deposits of such a mineral as amazonite were found. It has an amazing color, and its layers are very close. Helicopters are used for its extraction, because it is not possible to deliver it in any other way. Kyanite, garnet, and staurolite were found in the same places. But the work is carried out by the hands of enthusiasts and small work teams.

Production features in different countries

The norms for the extraction and exploration of gems-minerals in all countries are set differently. For example, in the United States there is a well-known topaz valley and topaz mining can be carried out there. a common person but only with hand tools. And if in some countries the law requires additional permission for the extraction of certain precious stones, then in Africa there are villages that exist only at the expense of gold placers found nearby. Quartz, emeralds, aquamarines, colored tourmaline were also found here. The villagers work off the placers with their hands, and then resell them to the buyer, receiving a pittance for this. However, these finds then end up in jewelry markets already at an artificially high price. The same applies to deposits in Guinea, where the extraction of diamond placers does not require special costs, besides, there is no state control and customs strictness. As a result, there is no real estimate of the volumes of mined gems.

Features of production in Russia

As for Russia, there is no effect of legislative norms and rules here either. IN federal law only diamonds, emeralds, rubies, sapphires, alexandrite, pearls and amber are described. However, there are over a thousand different gem minerals on the Russian market, and most of the deposits have already been explored.

Many gems are unique and their cost is very high, for example, this is the Yakut charoite. Stone lilac color remarkably polishable, used for making fine jewelry and various decors. No more than a hundred tons are mined annually, otherwise, if the production is exceeded, depletion of reserves is possible. This rare gem, even when uncut, can cost upwards of $100 per kilogram.

Let's give an example on the situation with jasper. Even in the USSR, work was carried out on the largest deposit near Orenburg, then variegated jasper was mined almost three hundred tons a year. The stone was used for the construction of the metro in Moscow and with its help the decoration of the Kremlin was carried out. However, since the 1990s, the deposit has been abandoned, although there was still a reserve of about seven thousand tons. Currently, work is being restored, at least a mining license has been issued, but for some reason a St. Petersburg company, and not local prospectors, took up this task.

The extraction of precious gems is considered to be a time-consuming and troublesome business, and there are many good reasons for this. First of all, as it should be, geological exploration is not carried out. The last successful find happened in the mid-90s. Then black jasper was discovered in the Republic of Tuva. The gem is not particularly beautiful, but it has amazing strength. A preliminary assessment showed that the found deposit is over five hundred thousand tons. And this is perhaps the only success for last years. The remaining deposits, as a rule, are mostly little explored or have already developed their own.

And as for non-precious gems, they are generally, as a rule, an accidental discovery due to the discovery of other fossils in the neighborhood. In addition, if the extraction of precious stones is at least somehow accounted for by the state, a special license is issued, and so on, then, as for the rest of the minerals, they are completely devoid of any account. For example, Buryatia is famous for its jade deposits. There is also green jade, black and even valuable white jade. According to official statistics, the extraction is over two hundred tons annually, and almost seven hundred tons of stone is mined illegally. Most of the minerals are not processed and are shipped to China, which greatly appreciates this stone and uses it in many industries. In Chinese markets, the price of jade reaches almost two hundred dollars per kilogram, and if it is some kind of product, then ten times higher. And in Russia, the price of a stone is ten to fifteen dollars a kilogram. Thus, in the budget of Buryatia there is an annual loss of huge amounts of money.

And while the authorities are solving the issue with gems at the legislative level, you should not despair, but it is better to visit such extraordinary lands where you can relax and replenish your own collection of gem minerals. This is Adygea, where quartz, calcite and other minerals are found in the Belorechenskoye deposit, and the coast of the White Sea with amethyst deposits and other magnificent places. After all, what is income for state power is a happy opportunity for ordinary people to enjoy natural wonders and feel the energy of unusual fabulous gems.

In addition to the famous tea plantations, Sri Lanka is also famous for its precious stones. It occupies a leading position in the extraction of precious stones. The process of mining stones has remained unchanged since ancient times. It's still handmade. Mines are dug with a pick and shovel, usually close to the river bank. The rock itself is lifted up in baskets or buckets with ropes, and then washed under running water or in the nearest river. Then special people get to work, trying to find a gem in a handful of stones. Sometimes you can find one, two or even a whole handful of stones, but often the seekers are left empty-handed. And the whole process starts all over again. Almost all gems, especially large ones, are sold at auction. During the time of the Arab merchants, the island was called Serendip or the island of precious stones. Under the name "Serendip", Sri Lanka entered the stories about Sinbad the Sailor, who visited Sri Lanka twice, and the legends of 1000 and 1 nights. famous traveler Marco Polo saw a ruby as thick as a human hand that adorned Ruvanveli Dagoba in Anuradhapura. The famous blue sapphire Blue Beauty"of 400 carats, adorning the English crown, as well as the Star of India sapphire of 536 carats, exhibited in the New York Museum, originally from Sri Lanka, namely from the city of Ratnapura, which has been an important center for the extraction of precious stones from time immemorial. 01. Mining is carried out only manually. Of the automation equipment, only pumps that constantly pump out water. Digging right in the rice fields. If you turn off the pump, the mine will flood in about an hour. If the mine is deep, then air is forced into the adits, by a motor pump.
02. Previously, excavators and other heavy equipment were used for mining, but after them there were lakes.
03. In Sri Lanka, about 90% of the land contains almost half of the 200 varieties of precious and semi-precious stones that exist in the world.
04. To mine stones, you need a license, it costs $5,000 a year.
05. In such wicker baskets, soil is passed upstairs, where it is washed in search of precious stones.
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07. More serious development from several mines. The depth of the mine is from 7 to 30 meters.
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09. Development here was stopped a few months ago, the mine is abandoned.
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11. All raised clay is washed.
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13. After 10 minutes, only small pebbles remain in a special basket.
14. Among them, precious sapphires, rubies, alexandrites, etc. are found. Sometimes you can dig for 2-3 months and not find a single stone.
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16. Here are some semi-precious stones. After the end of the shift, they are handed over to the market. Until you start processing a stone, it is not clear how valuable it is, so no one will give much for an unprocessed stone. But if the stone turns out to be clean, without impurities, it can be very expensive, but the one who got it will not know about it. In order not to lose money in the event of such luck, many miners work with families, some mine, others process.
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18. A real Marlboro kauba.
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20. 21.
22. After processing, the stones go to the store.
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24. Store them in envelopes. Only a professional can understand where a real valuable stone is. Sapphires, for example, are heated to give them desired color. Real pure sapphire does not need heat treatment and is very expensive. The price of one carat reaches 10,000 dollars.
25. Handbag for expensive stones.
26. There are grenades in Sri Lanka various kinds: essonite (orange-brown), almandine (fiery red), rhodolite (pale red), spesartite (brown-red), as well as yellowish red garnet. You can also find greenish-yellow alexandrite here, cat eye, Moon rock(light, translucent, with bluish reflections), Amethyst, Aquamarine, Beryl, Topaz (usually yellow-brown), Zircon, Tourmaline Chrysoberyl (golden yellow or greenish color), and Spinel.
27. Sapphires, average price$300 per carat.
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