Diamonds of Yakutia
Since ancient times, diamonds have been recognized as the most exquisite and expensive jewelry. But the scope of use of precious stones is not limited to jewelry. On the contrary, most of the mined stones are used for production needs.
Diamonds are used in almost all industries. They are used to make tips for cutters and drills, which are used in the processing of metals, hard alloys, glass and other synthetic materials. This application is economically justified, since diamond has very high strength and in this regard is superior to similar tools made of carbide metal.
Diamond powder, obtained by crushing low-grade raw materials, is used to cut other precious stones, including diamonds themselves.
Historical excursion
In the city of Mirny, in Yakutia, there is one of the world's largest diamond quarries - the Mir kimberlite pipe.
Diamond ore lies in the earth's crust, in the so-called kimberlite pipes. They were formed several million years ago as a result of the eruption of underground volcanoes. Under the influence of enormous pressure and high temperatures, carbon took on a strong crystalline form, which today is called diamond stone.
Kimberlite pipes have the shape of a cone, the base of which reaches the surface, and the tip goes 2 kilometers deep into the earth's crust. This form of occurrence of diamond ores allows for open-pit mining. As a rule, once the pit reaches a depth of 300–600 meters, it is closed, and further development is carried out underground.
Table of the world's largest diamonds
In the world, the first explored diamond deposits are considered to be mines in Africa; it was from them that active industrial production began more than a hundred years ago. In Russia, kimberlite mines were discovered in the middle of the last century in Yakutia.
The first significant deposit was discovered in 1954, it was called Zarnitsa. Geologists made big bets on Yakutia and were not mistaken; a year later, another major deposit was explored - “Mir”.
They say that when the data was confirmed, an encrypted telegram was sent to Moscow: “We lit the peace pipe, the tobacco is excellent.” During the development of this field, the city of the same name, Mirny, grew in its vicinity. Today the city's population exceeds 35 thousand people. It is noteworthy that 80% of able-bodied citizens are employees of the largest diamond mining company.
Grade
The appraisal of precious stones itself takes place in Moscow. There's pretty strict security there. Eyewitnesses say that in order to see the beauty of diamonds with your own eyes, you will have to leave the bag outside.
What is included in the assessment of such expensive minerals? The closest approximation to reality of the price of a stone, as well as the determination of the number of diamonds you can get from it. For example, one rough stone can contain up to ten diamonds!
Also during grading, 3D scanning of the diamond is used to see the potential dimensions of the diamond and its final shape. Special software from Sarine helps predict the potential size of a diamond, its shape and price. One employee said: “Everything is done to maximize potential income.”
Main diamond deposits in Russia
The following kimberlite pipe locations have been explored on the territory of the Russian Federation to date:
The city of Mirny is the diamond “capital” of Russia, located in Yakutia (Sakha) 1200 km away. from Yakutsk.
- The Republic of Sakha (Yakutia);
- Perm region;
- Arhangelsk region.
The leader in terms of production volumes is undoubtedly Yakutia; the local industry accounts for 82% of all mined diamonds. The Arkhangelsk region is in second place – 17.5%. Less than one percent of fossil diamonds come from the Perm region.
In Yakutia, 12 diamond-bearing areas have been identified and explored. Three are currently being actively developed:
Kimberlite pipe “Udachnaya”
- Daldyno-Alaktinsky;
- Anabarsky;
- Malo-Botuobinsky.
Well-known kimberlite pipes are located in these areas:
- Successful;
- International;
- World.
The Udachnaya kimberlite pipe was the first to be actively developed, then the International and Mir.
The International deposit was discovered in 1969 and is located near the city of Mirny (15 km). The depth of explored diamond reserves here reaches 1220 m. Active development of the mine began in 1971 and has not stopped to this day.
When the quarry reached a depth of 284 meters, open-pit mining was mothballed and diamond ore continued to be extracted using the underground method. The mines began to be built in the 70s. It was the International Mine that became the first deposit in Russia where mining began to be carried out using the shaft method.
Unusual place
It is interesting that helicopters do not fly in places where kimberlite pipes are installed. Why? A huge funnel with a depth of almost 500 meters and a diameter of about one kilometer initiates updrafts that can seem to suck in aircraft.
The diamond quarry looks very beautiful: according to eyewitnesses, being at the bottom you feel dizzy, but when you rise up you experience euphoria. Some people even dream of being at the bottom of such a quarry with a parachute. Be that as it may, after reading this article, you most likely also want to take a closer look at the diamond mining industry.
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Quarry method of extracting diamond ore
Open-pit mining, including diamonds, is the simplest and cheapest option. Its basis is to extract ore to the surface using machines - dump trucks, loaders.
First, the drilling rig makes a hole, then explosives are placed in it. Gentle technologies are used, since diamond can crack and lose integrity, even though it is the hardest of minerals. After blasting, rock fragments are loaded onto dump trucks and transported to the processing plant.
Yakutia has a rather harsh climate; winter here lasts eight months, and the air temperature sometimes drops to -60 °C. To ensure uninterrupted operations, equipment that can withstand such temperature conditions is required.
For quarry work, loaders, excavators, and dump trucks of such brands as BelAZ, Cat, Komatsu are used. Such machines are capable of transporting up to 136 tons of ore; about a hundred machines and mechanisms are used to ensure the operation of one quarry.
However, despite all the advantages of the open diamond mining method, its application is limited. As a rule, the depth of quarries should not reach 600 meters. In the funnel of the International Pipe, a dump truck, rising from the bottom to the surface along a serpentine road, covers 10 km.
Underground method of mining diamond ore
Equipment for underground diamond mining
When open-pit mining of ore becomes impossible, they move on to the construction of underground mines. This mining method requires much more costs, but even with large investments in its organization, it still remains economically justified, since the depth of kimberlite pipes often reaches 1.5 km.
After the closure of the International Quarry, the remaining reserves of diamond ore, according to expert estimates, will be enough for another 25 years of uninterrupted production. In order to prepare the mine for operation, significant capital investments will be required - $3-4 billion. But most of the investments are required only at the initial stage of construction; significantly smaller amounts of money will be needed for operation.
The construction of underground mines is carried out in difficult climatic conditions. Low temperatures are complemented by aggressive groundwater. They are highly mineralized, and under their influence, wheel tires are corroded. Water must be constantly pumped out. This happens in two stages. First, with the help of pumps, liquid is taken and pumped into bunkers located in the middle of the shaft, then, after they are filled, the water from them is pumped to the surface.
Diamonds are mined underground using combine mining.
Diamonds are mined underground using combine mining. The cutters of the machine rotate, and under their pressure the rock is destroyed. It is then loaded onto special machines that deliver the ore to the surface. The scheme is quite simple and similar to the quarry method; sometimes it is possible to use explosives to destroy kimberlite rock. The most expensive and difficult thing is ensuring the safe operation of miners and equipment underground.
To transport people to their place of work, a cage similar to an elevator is used; up to 20 people can fit in it. The descent time to the bottom point is seven minutes. Oxygen must be constantly supplied to the mine; for this purpose, a cage shaft is built; it serves as an elevator for lowering and lifting miners, cargo, as well as for supplying air to the mine.
The depth of this pillar is 1065 m, diameter is 6.5 meters. A skip shaft is built to release rock and can be used as an emergency lift for people. Niches have been created underground for miners to rest; they are located at a depth of 300 meters; the temperature here is comfortable, dry and warm.
Where and how are diamonds mined? Diamonds of Yakutia
Diamond ore beneficiation
Medium crushing body:
After diamond ore is extracted by any method, it is sent to a processing plant, where it will undergo several stages of purification. First, the rock must be crushed, since pieces of 1.5 meters in size are often encountered. Using cone and jaw crushers, the rock is crushed to a diameter of less than 0.5 meters. Next, the raw materials are sent to classifiers, where the ore is separated by density and size using a stream of water. The washed rock enters the vibrating sieve; it consists of several levels, each subsequent one has smaller holes, thus the raw materials are sorted into fractions. The vibrating sieve is often called "Rumble" because it makes a lot of noise when it operates.
Wet autogenous mill
The next step is necessary to isolate diamonds and medium-sized pieces of ore. Jigging machines deliver a pulsating stream of water, which dissolves or dislodges the rock, and the diamonds settle at the bottom of the installation. The rock of smaller fractions is processed in a different way, using chemical reagents - pneumatic flotation.
Substances, interacting with water, foam, and small particles of diamonds stick to the bubbles and are thus isolated from the rock.
X-ray luminescent separation
The main and control stage of diamond ore enrichment is X-ray luminescence separation. Along a special conveyor belt, the raw material is fed into blocks equipped with X-rays, when exposed to radiation, the diamond luminesces, and the device detects the flashes and knocks the diamond out of the total mass with a stream of air. Since a small amount of rock is blown out with the air flow, another stage of isolating, cleaning and sorting the diamonds is necessary.
These actions are then performed by people. Each diamond goes through three people who clean the stone from impurities, sort it into fractions, and evaluate its purity.
Diamond is not a standardized product; its value is influenced by a combination of various qualities - clarity, color and size. Each stone is assessed by a specialist. After completion of all stages of enrichment, diamonds of larger fractions are sent for cutting or sale in pure form, and fine-grained sand is intended for sale to industrial enterprises, from which tools and other materials will be made.
Important detail
It is worth considering that working with precious stones requires care and an unusually scrupulous attitude. Here is what an ALROSA employee says about this: “Whenever you make a decision, there is no turning back. Your choice could result in either a profit or a loss of $1 million! Cutting the stones is very difficult and can take months.” Becoming a cutting specialist requires five years of training.
Before being sent to jewelry stores, the diamond is polished using a rotating wheel. Essentially, diamonds are polished by other diamonds.
Interestingly, according to the company, in September of this year ALROSA sold rough diamonds worth $256.5 million. We have already mentioned that large gemstones are sold at international auctions. In March of this year, the firm held a rough diamond auction in New York, which brought in more than $11 million in revenue.
