How limestone is mined. Limestone mining methods Where and how limestone is mined

Limestone is a sedimentary rock of organic origin. There is also a chemogenic origin of limestone, when the rock is formed as a result of chemical precipitation during the evaporation of water or from aqueous solutions. The basis of the rock is mainly calcium carbonate, presented in the form of calcite crystals of various sizes. The extraction of limestone is in demand, since a person uses this rock in many areas.

Description

The basis of limestone is calcium carbonate - a substance that can dissolve in water. As a result, karst is formed. It can decompose into bases and carbon dioxide. This is carried out at great depths, because due to the influence of the heat of the Earth, limestone forms a gas for mineral waters.

Limestone may include impurities of clay minerals, dolomite, quartz, gypsum, pyrite. Natural limestone has a light gray color, although it can be black and white. Impurities give a blue, pink, yellow tint. Limestone mining is in demand because of its wide application. The breed is durable, known for its unique characteristics that make it unlike other materials.

Classification

A common type of rock is the shell rock, which consists of the shells of marine animals and their fragments. There are other types of limestone:

• Bryozoan, which includes the remains of bryozoans - small invertebrates living in colonies in the seas.
• Nummulitic, consisting of extinct unicellular organisms nummulites.
• Marble. It happens thinly layered and massively layered.

During metamorphism, limestone undergoes a process of recrystallization, due to which this rock forms marble.

Monomineral rock is limestone, the method of extraction of which may differ, depending on the type of impurities, structure, geological age. There are organizations that mine limestone. Places and methods of extraction are determined by the terrain, types of rocks and other characteristics.

Place of Birth

As can be seen from the above, limestone is considered to be a sedimentary rock that appeared with the participation of living organisms living in sea basins. The breed is mined in many regions of our country and other states. Russia is considered one of the leaders in terms of its presence.

Limestone is considered the "building material" for mountain ranges. An example is the Alps, although it can occur in other mountainous areas. Limestone mining takes place all over the world. There are many reserves in our country. Moreover, all limestone mining sites make it possible to obtain different types of natural material: dense, white, flux, shell-oolitic.

Limestone mining is known in Russia. Deposits are popular in the western part of the country. Developments are carried out from the Belgorod and Tula regions to Moscow, the Vologda, Voronezh regions. Mining is carried out near St. Petersburg, in the Krasnodar Territory, Arkhangelsk, in the Urals, in Siberia. Of the neighboring countries, there are deposits in the Donetsk region of Ukraine.

Mining methods

Mining is carried out by an open pit method. The top layer of soil and clay is removed. This is how a quarry is formed. Limestone mining involves pyrotechnical work to crush and detach portions of rock. Then it is taken out by cars for processing.

The breaking method is considered the world's first mining method. This name was obtained due to the fact that the rock was removed with crowbars, and then stones were knocked out of the formation with hammers. An alternative to this method is now being used. Explosive method is used. A small crumb is obtained from the breed. The excavator collects it, loads it onto dump trucks, and then everything is transported to the plant, where it is processed and cleaned.

There is a special device for the excavator, with which the extraction of limestone can be carried out without explosion. The driver changes the bucket for a mounted machine that loosens the rock. This method is used in areas with high population density. There is a method of extraction by a milling combine. This is the most profitable option. At the same time, rock is mined, crushed and transported.

Features of the traditional way

The old method is used to extract limestone slabs. You just need to find a way out from under the ground. Then the area where mining will be carried out is cleared with a shovel.

With a crowbar, you need to create a crack in the limestone slab, and then pry off the edge of the slab and lift it up. Since limestone is located underground in layers, only a small plate of it should be raised. It must be pulled out of the place where the limestone lies. They cut the rock with an ordinary saw. To simplify the work, the tool is moistened in water.

explosive method

Limestone is obtained using the explosive method. First, it is necessary to open the deposits, removing earth, clay and substandard limestone from them with the help of bulldozers. Wells are drilled near the edge of the mining site and explosives are placed there. With the help of explosions, limestone layers are broken off, which then needs to be loaded into dump trucks and taken out for further processing.

Then the quarry where the extraction was carried out is covered with earth, planted with herbs and plants. This method is used in large deposits. And in small ones, the explosive method should not be used. Then the limestone is taken out in blocks similar to the shape of rectangles. This technology is called bar working.

The work is done by different machines that cut stones. You definitely need an excavator. The technology has its advantages:

• Simplicity.
• Nice block shape.
• Easy transport and handling.

Since limestone has a porous structure, it is used in the construction industry. From it erect temples, palaces, estates.

Types and colors of limestone

Limestone mining allows you to get different rocks. They differ in color, structure, chemical composition, origin, area of ​​use and other characteristics. By type of application, limestones of different colors are found:

• White and gray - "pure" rock, in which there are no impurities.
• Red and brown are limestones with manganese.
• Yellow and brown - contain iron.
• Green - stones with seaweed inclusions.
• Dark gray and black - have organic impurities.

According to the structure and chemical composition, the rock is:

• Dolomitized - contains 4-17% magnesium oxide. If the proportion of magnesium increases, then dolomites are formed.
• Marbled - carbonate limestones with organic inclusions. Their palette can be from beige to gray-blue tones.
• Coral. The rocks have a porous structure. They are transformed into reefs from mollusk shells and shells of marine life.
• Clayey. The rock has a composition similar to limestone and marl. The formations are softer than limestones, brittle compared to shale clays.

By origin, limestones are:

• Jurassic - a rock with a history of hundreds of millions of years, has high strength, density and fine grain. In the Middle Ages, limestone was called "marble" due to the fact that it could be polished.
• Putilovsky. This limestone has unique physical characteristics, low moisture absorption and abrasion. During the formation of St. Petersburg was the main building material. It is named after the place of extraction - the Putilov quarry, located in the Leningrad region.

Applications

In the metallurgical industry, it is used as a flux. It is considered the main ingredient during the creation of cement and lime. It is used as an auxiliary component for the production of soda, mineral fertilizers, paper, sugar, glass.

The material is also used to produce rubber, paints, soaps, plastics, mineral wool. It is in demand in the construction industry for the manufacture of facing and wall blocks. It is used for the construction of foundations, roads. Limestone mining makes it possible to provide building materials for the entire country.

A detailed production report from the Sokolsko-Sitovskoye flux limestone quarry, located a couple of kilometers northeast of Lipetsk. Under the cut are large excavators, BelAZ trucks, a factory, conveyors, an explosion and much more...

1. Some official data: The quarry is being developed by Studenovskaya Joint-Stock Mining Company, currently a member of the NLMK Group and one of the Russian leaders in the production of flux limestone, used mainly in the metallurgical industry and construction.

2. Mining volumes account for more than 15% of the mined flux limestone in Russia.

3. The dimensions of the quarry are impressive: 1500x500 meters, and the depth is 50 meters. Here you can easily build more than 10 football fields or lay a track for Formula 1...




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4. According to geologists, the reserves of raw materials in the quarry at the current capacity will be enough for at least 30 years of operation.




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5. Limestone is a widespread sedimentary rock formed with the participation of living organisms in marine basins. Once upon a time, approximately 350-370 million years ago, in the Devonian period of the Paleozoic era, the Lipetsk region, like many regions of the central part of Russia, was a sea. Often in the fragments of the rock you can find fossil remains of the ancient life of those years ...

6. The deposit is developed by an open method. The technological process of mining can be divided into the following main types of work:
Stripping works
mining operations
Dumping and mining reclamation
Transport work
Mineral processing




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7. Overburden works.
First, with the help of a bulldozer or a loader, the top fertile layer of soil is removed - black soil, and stored for subsequent reclamation of lands disturbed by mining. This is followed by a clay layer with a thickness of about 20 meters, which is worked out by electric excavators with a bucket capacity of 8-10 cubic meters. Overburden works also include partial sampling of substandard (poor quality) limestone, which is located directly under the clay layer.

8. This photo clearly shows a section of the “quarry pie”: a layer of clay, a layer of substandard limestone and an even ledge of a mineral. The crumbling hill of limestone under the ledge is a consequence of the explosion. It is precisely these “consequences of the cry” that are loaded into BelAZ trucks and taken to the factory. And all overburden rocks are taken to the internal dump.




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9. Mining work.
It is customary for miners to say production, with an emphasis on the first syllable. Limestone mining itself is preceded by drilling and blasting - the most spectacular part of the whole process.

10. A hard layer of limestone, which cannot be scooped up with an excavator bucket, has to be drilled, explosive materials are placed in it and blown up. For drilling, drilling rigs of the SBR type, powered by electricity, are used.

11. Drilling rigs are serious, they drill holes with a diameter of 16 cm to a depth of up to 24 meters (7 floors). It takes 50 minutes to drill one well. A string of wells, elongated in a line, is drilled one by one 5 meters from the edge of the cliff.

12. Brave driller!

13. For the explosion, industrial and conversion explosives are used, the acquisition of which requires a whole bunch of various permits and licenses, as well as special vehicles for transportation and armed guards. You can't just buy gunpowder at the market ...

14. TNT checkers serve as a detonator.

15. On average, about 30 wells are drilled to carry out one explosion, where a total of 5-6 tons of explosives are laid.

16. To connect all the wells with explosives into a single circuit, a detonating cord is used.

17. An explosion is a very responsible matter! The quarry is completely cordoned off, guards are posted in the area of ​​​​the future explosion. All equipment is taken to a safe distance, and BelAZ vehicles generally leave the quarry. Before the explosion, all cordon posts are polled by radio and the situation is clarified. If everything is fine, permission is given to carry out blasting. (The guard post and the transformer box are also being taken away).

18. The wells are not blown up simultaneously, but with a delay of several hundredths of a second, otherwise there will be an earthquake, and most of the buildings in Lipetsk will have windows blown out.

19. For a sense of scale - on the right side of the frame there is an excavator the size of a 4-story building ... Small pieces of rock can fly away to a distance comparable to the height of the main building of Moscow State University - 250 meters.

20. It can be seen how heavy pieces of hard rock are separated from the ledge in even rows and fall down.

21. The whole explosion passes in a few seconds and is well heard in the city. This is what collapsed rock looks like. After the smoke clears and the dust settles, the explosives will check for failed charges, after which the excavators and BelAZ trucks will go about their work.

22. The rock is loaded into BelAZ using a mechanical shovel (that is, an excavator), or rather, using a self-propelled full-turn excavation and loading machine. This monster runs on 6000 volt electricity, the photo shows a high-voltage cable that powers the excavator's engines. During a day of operation, the machine consumes as much energy as an ordinary nine-story residential building in a week.

23. At one time, the excavator can load 10 ordinary photographers, or 20 Chinese photographers.

25. The weight of such a bucket is 16 tons.

26. Each excavator employs two people to ensure the continuity of the production process.

27. In total, 6 large excavators (bucket with a volume of 8 and 10 cubic meters) and 2 smaller ones with a bucket volume of about 5 cubic meters work in the quarry.

28. Sometimes appliances break down. For example, the main gear of this excavator has failed and it is being repaired right in the quarry. The diameter of limply hanging steel ropes is 4 cm.

29. And this is a now decommissioned veteran who honestly gave the enterprise about 40 years. Despite his considerable age and shabby appearance, grandfather, in case of emergency, can be taken to work in a quarry.

30. Dumping and mining reclamation.
At a constant depth, the quarry bowl constantly moves in the direction along which the limestone occurs. On one side of the quarry, overburden is removed and limestone is mined, on the other, the mined-out space is filled with overburden, limestone crushing screenings and black soil.




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32. Screenings are brought from the crushing and processing plant in dump cars, which are formed after limestone crushing and are not suitable for use. The excavator dumps everything on the dump, filling the mined-out space of the quarry. Then the dumps will be covered with previously opened soil and top with black soil.

33. This mechanical shovel is smaller - with a bucket for 5 cubes.

34. Next, plowing of the land is carried out and biological reclamation is carried out - the sowing of land with useful plants. In a few years, the recultivated lands can be used again for agricultural purposes. Previously, the quarry started right from the landings (on the right in the frame) and has shifted 600 meters in 20 years. Now there is a field. In the future, the quarry may advance another 2.7 kilometers.

35. Transport work.
Every day, 12 BelAZ trucks operate on the line in the quarry, which ensure the transportation of overburden rock to dumps, and the mined limestone to the DOF - to the crushing and processing plant.

36. Belazists work around the clock in three shifts, eight hours each. During the day, BelAZ makes up to 100 walkers, and transports up to 16 thousand tons of mined limestone. In three months, the car runs the distance from Moscow to Vladivostok.

37. The carrying capacity of such a BelAZ is 55 tons, more than its own weight. BelAZ trucks with a higher carrying capacity in this quarry are not advisable to use for several reasons: the depth of the quarry, the distance of transportation, the volume of production, and so on. This baby mammoth is powered by a 700 hp diesel engine.

38. If during transportation from BelAZ something falls out onto the road, such as a large stone, a special wheeled bulldozer will remove it back to the face, to the excavator.

39. They actively fight dust in the quarry, the roads are constantly doused with a special watering can. And in winter, watering is replaced by sprinkling with a sand-salt mixture.

40. To take this shot, I had to ask the driver on the radio (each piece of equipment in the quarry is equipped with a radio station) to drive outside the watered road. The permissible speed in the quarry is 20 km/h.

41. The quarry has 14 km of technological roads built in bulk, there are also electrification and substations to power excavators. The roads are excellent, you can easily move on them by car.

42. Shop for the repair and maintenance of BelAZ.

44. The body and engine were removed from this BelAZ.

45. The mined mineral is brought to the DOF and unloaded into the receiving bunker, before that the dump truck is weighed and by simply subtracting the weight of the empty BelAZ, the weight of the cargo is obtained.

46. ​​Receiving hopper.

47. Mineral processing.
This is the first building of the factory - the building of coarse crushing. Here, the jaw crusher rough crushes large pieces of rock. Fractions up to 10 cm in size are obtained.

49. Approximately 15,000 tons of rock are transported on a conveyor belt per day.

50. Cone crusher performs medium crushing.

51. Cunning system of vibrating screens. In closed devices, the products are divided into fractions (according to the size of the stones) and distributed along the conveyors.

52. An ordinary five-story house can easily fit in the workshop ...

53. Quite small limestone - screenings up to 1 cm are sent for unloading into dump cars for subsequent transportation to the quarry dump.

54. Corps of sorting and loading. The finished product is delivered here, where it is loaded into railway wagons. The main consumer of the products is the Novolipetsk Iron and Steel Works.

56. One car includes 69 tons of crushed stone.

58. Loading into vehicles is taking place nearby.

59. Work in a quarry does not stop at night. For this, backlighting works on excavators.

61. UFO.

62. The 55-ton BelAZ trucks used in the quarry are relatively small, and by miners' standards, they are just babies. Someday I will definitely look at the work of 320-ton trucks!

63. Night quarry and factory are beautiful!

Separately, I want to say about the people with whom I worked for two shooting days. Open, kind, cheerful miners, happy to talk about their work and equipment. Real men!
Thanks to all staff

Limestone mining methods

This kind of rock, like natural limestone, is widely used in the construction industry. Entire houses are built from this natural rock. Facing of facades of buildings - the main way of application of this stone. Layers of first-class limestone are used, including for laying pavements. Limestone is famous for its fairly good strength, durability, and excellent aesthetic characteristics.

Where is limestone mined?

The mass distribution of this stone makes it possible to extract limestone in various parts of the world. Many deposits of this stone have been found in the Russian Federation and abroad. At most of these deposits, active work is underway to extract this magnificent natural stone. The western part of the Russian Federation is recognized as the largest territory for the extraction of limestone. Quarries in which this material is obtained are in the regions: Leningrad, Arkhangelsk, Tula, Vologda, Voronezh and Belgorod. In addition, limestone is mined in the Moscow region, in the Urals and the North Caucasus, in Siberia.

To extract limestone, the following main methods are used:

• Explosive;
• excavator;
• Combine.

Each of these methods has its own specifics.

Explosive mining

This method is considered the easiest, most economical in terms of financial costs and therefore the most popular. Explosives are placed in a rock layer in certain places, as a result of the explosion, fragments are formed that have a wide variety of sizes: from large boulders to small crumbs. They are transported from the quarry to specialized enterprises, where they are sorted and further processed.

Mining with excavators

This method is less destructive than explosive. Heavy excavator machines working in quarries are hung with specialized equipment designed to quickly loosen the rock. There are several designs of such units, they can be hydraulically or mechanically driven. It should be noted that these units are arranged in such a way that their replacement takes a matter of seconds: the baking powder quickly changes to a bucket, with which the mined rock is loaded into a dump truck, and then installed back. The use of this method allows for partial sorting of limestone into classes (fractions) already in the quarry itself.

Mining with milling machines

A specialized milling combine grinds stones into pieces of a specific size directly in the quarry. This method is very effective from an economic point of view, since there is no need to carry out additional processing of the stone in a specialized production. It is estimated that the total waste at the time of mining by milling combines is approximately 10% lower than other excavators with attachments.

What are the types of limestone

Limestones have chemical properties, color, structure, scope, origin and other characteristic features of natural stone. According to the method of application, there are limestones of various colors: “pure” rock without impurities - has a white or gray color. A stone with the presence of manganese has a red or brown color. With iron content - yellow and brown. With inclusions of impurities of seaweed - green. With organic additions - dark gray and black colors.

This type of limestone, like shell rock, is a rock that mainly consists of sea shells and their fragments. Limestone is distinguished by types: nummulite, bryozoan and marble-like - massively layered and thinly layered. Directly in the process of modification, limestone recrystallizes and forms marble.

Benefits of limestone

Compared with other similar raw materials, this material is characterized by these advantages:

• The main distinguishing feature is the highest degree of environmental friendliness;
• Easily processed, due to which it is easy to give this stone almost any shape;
• Even with regular negative impacts of meteorological phenomena, it is able to keep its appearance much longer, unlike, for example, tiles for facing or bricks. Due to these qualities, limestone is often used to finish the lower parts of the walls of buildings;
• Moisture in the premises will be kept at an acceptable level, due to the fact that limestone has a porous structure. This distinctive feature contributes to the rapid absorption of moisture from the environment;
• Limestone stone has impeccable properties for interior and exterior wall cladding, high sound and heat insulation, suitable for use in the construction industry.

Limestone is predominantly mined in open pit mines. Limestone without clay or sand impurities is rare. Limestone is mined mainly by drilling and blasting, sometimes mining is done with the help of rippers and bulldozers.

To do this, boreholes with a diameter of 100 ... 300 mm are passed, located in one or several rows in a checkerboard pattern, explosives are laid and a mass explosion is carried out. Drilling of wells is carried out with the help of rope-percussion machines, pneumatic percussion or drilling machines.

Recently, powerful cone drilling rigs with a capacity of up to 30 m / h have been used (Figure 1.51). Rocks are loaded by excavators with a bucket capacity of up to 8 m 3 or by loaders.

After the explosion, the material may contain oversized pieces - large pieces that the excavator cannot capture. Oversized cutting is carried out by an explosive method using overhead charges or small holes, as well as with the help of butoboys. The drilling machine with the help of special attachments is quickly converted into a rock drill.

In some cases, to reduce the cost of mining, blasting is abandoned and mining is carried out with the help of special rippers mounted on powerful tractor tractors. Their application makes it possible to solve two important problems of the integrated use of subsoil: the organization of selective mining of rocks of various quality and the extraction of raw materials in protected areas where the use of blasting is unacceptable. The efficiency of loosening depends on the strength of the rock, the degree of its fracturing, the engine power of the loosening-bulldozer unit, the total mass and tractive effort. Abroad, in many enterprises, instead of the explosive method, mechanical loosening is also used.

The blasted ore is transported to a crushing plant, which can operate in one or two stages. Excavators or loaders are used to load the blasted rock. If necessary, the crushed rock is released in washing drums from clay and sand pollution. The limestone of some deposits contains only minor amounts of contaminants, so washing may not be necessary. The blown and washed material is then classified by size into separate fractions for firing in a kiln and for sale.

Limestone powder is also produced from limestone, for which fine grinding is carried out while drying, for example, high-speed hammer mills are used.

Upon receipt of high-quality clinkers, selective extraction of raw materials is carried out, i.e. batches of raw materials of the required composition are mined with a minimum content of harmful impurities. When mining softer rocks (for example, chalk), the need for blasting is eliminated. Soft rocks are mined using heavy bulldozers or bucket wheel excavators.

Exploded ore is transported by dump trucks to the crushing plant, which can operate in one or more stages.

Lime firing

The purpose of lime burning is to convert calcium carbonate to calcium oxide. Theoretically, this requires 3154 kJ/kg CaO (at 20 °C). At 900 °C, the partial pressure of CO 2 reaches 1 bar. In practice, the firing temperature of lime is much higher. A number of users (eg steel mills) want, in addition to a low residual CO 2 content, also a good reactivity, which is obtained only in certain types of furnaces. To this end, in addition to the quality of the fired product (chemical composition, crystal structure), the firing temperature first of all plays a role, which determines the pore structure of the fired product. In the following, the most important reactions and processes for lime firing are described in detail.

Sedimentary rock of organic, less often chemogenic origin, consisting mainly of calcium carbonate in the form of calcite crystals of various sizes.

Limestone, consisting mainly of the shells of marine animals and their fragments, is called shell rock. In addition, there are nummulite, bryozoan and marble-like limestones - massively layered and thinly layered. During metamorphism, limestone recrystallizes and forms marble.

Calcium carbonate, which is part of limestone, is able to slowly dissolve in water, and also decompose into carbon dioxide and the corresponding bases. The first process is the most important factor in the formation of karst, the second, occurring at great depths under the influence of the deep heat of the Earth, provides a source of gas for mineral waters.

Application area

Limestone is most widely used as a building material. The strength of many varieties of limestone is sufficient for the construction of multi-storey buildings. Thin layers of wear-resistant stone - limestone flagstone - are a finished material, such limestone is used to line buildings and pave paths.

Layered limestone with a pronounced weathering relief is valued by decorators, designers and landscape architects.

Manufacturers of natural stone products often successfully play with the biological origin of the rock. The shells of ancient mollusks, preserved in limestone deposits, become an important expressive element of finishing materials. Indispensable for any construction and cements - which, in turn, are made from a mixture of limestone and clay verified in percentage terms.

Marl - this is the name of the variety, which includes the right amount of aluminosilicates. It is mined in many regions of the world.

How limestone is mined

Limestone can be mined using an explosive method. To do this, you first need to open the deposits by removing the earth from them with the help of bulldozers. It is also necessary to remove clay and substandard limestone from them. Along the edge of the mining site, it is necessary to drill wells and put explosives there. If the explosions are properly organized, they will break off large layers of limestone, which later need to be loaded into dump trucks and taken to the processing site.