Where are 99% of diamonds in Russia mined?
About 1500 diamond kimberlite pipes have been discovered on the territory of the Sakha Republic. In Russia, it is here that the ALROSA group of companies produces 99% of all diamonds in our country. Yakut diamonds are valued slightly higher than stones from the Ural deposits, but their quantity puts Russian production in first place, ahead of Botswana and Canada.
How diamonds are mined
The development of a diamond mine in permafrost conditions imposes its own characteristics. In winter, temperatures can drop to -50ºС, -60ºС. In open-pit mining, blasting plays an important role. This is the only way to extract diamond ore from the bowels of the earth. Pyrotechnicians must carry out the detonation so that the walls of the quarry do not collapse and heavy equipment is not damaged. Excavators load the rock into large CAT-777D dump trucks, which rise along the serpentine road from the quarry and carry the cargo to the processing plant, where it is washed and valuable crystals are extracted. To extract diamonds from the total mass of crystals, special sheets greased with a greasy composition are used. Only diamonds have the property of sticking to fat-containing surfaces. Selected stones are sorted by quality and size. Jewelry-grade stones – approximately 10%-20% of the total volume of mined diamonds – are sent for cutting. The rest are classified as “technical” stones and are used for industrial needs and the production of tools. When unique specimens are discovered – large in mass, with a rare tint – a decision is made on the further fate of the stone. It may go to the Russian Diamond Fund or be sold at auction. When an open pit reaches a depth of 800 meters, it is mothballed. Next, a decision is made whether to continue production using a closed method. If the decision is positive, a modern mine is built at the mine, making it possible to extract diamonds underground at a depth of up to 1500 meters.
City Mirniy
The diamond capital of Russia is located literally on the edge of the Mir kimberlite pipe. According to local residents, it is only a 10-minute walk from the city to the quarry. After the discovery of the deposit in 1955, the working settlement grew to the size of a city in just 3,5 years. The city is located 1200 km from Yakutsk. The immediate population of Mirny is about 35000 people, 80% of the population work at the enterprises of the Alrosa Group of Companies. The city is provided with necessary goods through aviation, ships on the Lena River and transportation of goods along the winter road. There are direct flights from the city to Moscow and St. Petersburg. Due to the remoteness and inaccessibility of Mirny, food prices in the city are 2 times higher than on the mainland. “Mainland” is the territory to the west of the Ural Mountains. The Mir mine was mothballed in June 2001. Since 2009, diamond mining has continued again, but in a closed way. Residents of Mirny also work on a rotational basis at the Nyurba Mining and Processing Plant – here mining is carried out by open-pit and placer mining.
- About 3 people work at the mine in 7 shifts of 760 hours each.
- Mining is carried out 7 days a week.
There are only 2 holidays at diamond mining sites near Peaceful – Miner’s Day and New Year.
A special feature of the city is the construction of houses on stilts. This is done so that the heat from the building does not melt the permafrost under the foundation, otherwise the structure will sag. Another feature is the bright facades of the houses; they are designed to literally “color” the lives of city residents during the long winter. Bright facades protect residents from depression due to short daylight hours.
Alrosa has on its agenda the issue of reviving the Mirny mine. If geological exploration gives positive results and confirms the safety of further use of the ground part, work will begin in 2024. Their duration is approximately 6-8 years.
Diamonds were formed more than 300 million years ago. Kimberlite magma formed at a depth of 20-25 km. Magma gradually rose along faults in the earth’s crust, and when the upper layers could no longer contain the pressure of the rocks, an explosion occurred. The first such pipe was discovered in South Africa in the city of Kimberley – that’s where the name came from.
In the mid-50s, the richest primary diamond deposits were discovered in Yakutia, where about 1500 kimberlite pipes have been discovered to date. The development of deposits in Yakutia is carried out by the Russian company ALROSA, which produces 99% of diamonds in the Russian Federation and more than a quarter in the world.
The city of Mirny is the diamond “capital” of Russia, located in Yakutia (Sakha) 1200 km away. from Yakutsk.
The Mir diamond-bearing pipe, discovered by geologists in the summer of 1955, gave its name to a workers’ settlement that grew up in the taiga and became a city 3,5 years later.
The population of the city is about 35 thousand people. About 80% of this population works at enterprises associated with the ALROSA group of companies.
Lenin Square is the city center.
Providing Mirny with food and consumer goods occurs in the following ways: aviation, shipping supplies (for the period while navigation is open on the Lena) and along the winter road.
Il-76TD cargo plane of ALROSA airlines
The headquarters of Russia’s largest diamond mining company, ALROSA, is located in Mirny.
The history of the company began with the Yakutalmaz trust, formed to develop the primary diamond deposits of Yakutia in the early 1950s.
The main deposit of Yakutalmaz was the Mir kimberlite pipe, discovered on June 13, 1955.
Then geologists sent an encrypted telegram to Moscow: “We have lit the pipe of peace. The tobacco is excellent.”
The quarry is located in close proximity to Mirny.
From 1957 to 2001, $17 billion worth of diamonds were extracted from the deposit, and about 350 million m3 of rock were exported.
Over the years, the quarry expanded so much that dump trucks had to travel 8 km along a spiral road. from bottom to surface.
The quarry has a depth of 525 m and a diameter of 1,2 km, and is one of the largest in the world: the height of it could include the Ostankino TV tower.
The quarry was mothballed in June 2001 and since 2009, diamond ore has been mined underground at the Mir mine.
An aquifer passes through the area where the Mir pipe is located. Water is now entering the quarry and thus poses a threat to the mine underneath. Water must be continuously pumped out and directed into the faults that geologists have found in the earth’s crust.
The volume of diamond production at the mine in 2013 amounted to more than 2 million carats.
Resources (including reserves) – more than 40 million tons of ore.
About 760 people work at the mine.
The company operates seven days a week. The mine operates on a three-shift basis, with shifts lasting 7 hours.
Surveyors who determine the direction of excavation through the ore body.
9 roadheaders (Sandvik MR 620 and MR360) are used for excavation in the mine.
The combine is a machine with an executive body in the form of an arrow with a milling crown, which is equipped with cutting tools – teeth.
This Sandvik MR360 combine has 72 teeth made of hardened metal.
Since the teeth are subject to wear, they are inspected every shift and, if necessary, replaced with new ones.
To deliver ore from the combine to the ore pass, 8 loading and delivery vehicles (LODs) are used.
Main converter belt 1200 meters long from the kimberlite pipe to the ore pass skip.
The average diamond content exceeds 3 carats per ton.
From this place to the bottom of the quarry is about 20 meters.
To prevent flooding of the underground mine, a pillar 20 meters thick was left between the bottom of the quarry and the mine workings.
A waterproof layer is also laid at the bottom of the quarry, which prevents water from penetrating into the mine.
The mine also has a water collection system: first, groundwater is collected in special settling tanks, then it is supplied to an elevation of -310 meters, from where it is pumped to the surface.
In total, the mine operates 10 pumps with a capacity of 180 to 400 cubic meters per hour.
Installation of the main tape
And this is underground work on another pipe – International (Inter).
It is located 16 km from Mirny. Open-pit diamond mining here began in 1971, and when the quarry reached 1980 m by 284, it was mothballed. It was with Inter that underground diamond mining began in Yakutia.
“International” is the company’s richest kimberlite pipe in terms of diamond content in ore – more than 8 carats per ton.
In addition, Inter diamonds are of high quality and are valued on the world market.
The depth of the mine is 1065 meters. The pipe has been explored to 1220 meters.
The length of all workings here is more than 40 km.
The combine beats ore with a working tool (cone cutter) with cutters installed on it.
Next comes loading into loading and delivery vehicles, which transport the ore to the ore passes (mining openings designed to transport ore from the working area to the transport horizon located below), then the trolleys transport it to the main ore pass, through which it is fed into the skip shaft and delivered to surface.
1500 tons of ore are mined at Inter per day. The volume of diamond production in 2013 amounted to more than 4,3 million carats.
On average, one ton of rock contains 8,53 carats of diamonds.
So, in terms of diamond content per ton of mined ore from Inter, there are 2 tons of ore from Mir, 4 tons from Aikhal, or 8 tons from Udachninsky.
Work at the mine is carried out day and night, seven days a week. There are only two holidays – New Year and Miner’s Day.
Nyurbinskaya kimberlite pipe
The Nyurbinsky mining and processing plant was created in March 2000 for the development of deposits of the Nakyn ore field in the Nyurbinsky ulus of the Republic of Sakha (Yakutia) – the Nyurbinskaya and Botuobinskaya kimberlite pipes, as well as adjacent placers. Mining is carried out by open-pit and placer mining.
For the first time in the history of the association of Yakutalmaz and the Alrosa company, the Nyurbinsky GOK uses a rotational method – with the involvement of workers living in Mirny (320 km), in Nyurba (206 km) and in the village of Verkhnevilyuysk (235 km).
As of July 1, 2013, the depth of the Nyurbinsky quarry is 255 meters.
The open pit will be mined up to 450 meters (up to -200 meters from sea level). There is potential to operate down to -320 meters.
To transport ore and overburden rocks, dump trucks with large and especially heavy load capacity are used – from 40 to 136 tons.
Caterpillar CAT-777D dump trucks with a lifting capacity of 88 tons are used in the quarry.
Nyurba Mining and Processing Plant has the highest growth rate of natural diamond production in AK ALROSA.
The volume of diamond production in 2013 amounted to 6,5 million carats.
The average diamond content in the ore is 4,25 carats per ton.
There are about 300-400 carats in the back of such a dump truck.
From a quarry or mine, ore is transported by dump trucks to a factory, where the minerals themselves are extracted from it.
The beneficiation of diamonds from the Mirny Mining and Processing Plant is carried out at factory No. 3, which in the 70s of the last century was the flagship of the country’s diamond mining industry.
The capacity of the processing complex is 1415 thousand ore per year.
Coarse crushing body and jaw crusher.
In it, grinding occurs by friction of the movable “cheek” against the stationary one. 6 thousand tons of raw materials pass through the crusher per day.
Medium crushing housing
Designed for wet separation of solid material into sand (sediment, particle size up to 50 mm), and drain containing fine suspended particles.
Wet autogenous mill
Mill diameter – 7 meters
The stones are sifted through a sieve, where they are divided into groups according to size.
Finely processed rock is sent to spiral classifiers (screw separators), where all raw materials are separated depending on their density.
The heavy fraction comes from the outer side, and the light fraction comes from the inner side.
Fine material, together with the addition of aqueous reagents, enters a pneumatic flotation machine, where crystals of small classes adhere to foam bubbles and are sent for finishing. The smallest diamonds are extracted using a pneumatic flotation machine – from 2 mm or less.
This is a film machine where reagents are used to create a layer to which small diamond crystals adhere.
This separator uses the property of diamonds to glow in X-rays. The material, moving along the tray, is irradiated with X-rays. Once in the irradiation zone, the diamond begins to glow. After the flash, a special device detects the glow and sends a signal to the cutting device.
Central control panel of the processing plant.
The factory also has a finishing shop where diamonds are cleaned, scattered, hand-selected, sorted and packaged.
Diamond Sorting Center
All diamonds mined at the company’s fields in Yakutia are sent to the Sorting Center in Mirny. Here, diamonds are separated by size class, an initial assessment of raw materials from different deposits is carried out and its monitoring is carried out to plan the work of mining and processing plants.
There are no perfect crystals or two identical diamonds in nature, so their classification involves sorting.
16 sizes x 10 shapes x 5 qualities x 10 colors = 8000 positions.
Vibrating sieve screen. Its task is to divide small diamonds into size classes. For this, 4-8 sieves are used.
About 1500 stones are placed into the device at a time.
The larger ones are handled by weighing machines. The largest diamonds are sorted by people.
The shape, quality and color of crystals are determined by appraisers using magnifying glasses and microscopes.
Dozens of diamonds pass through a specialist per hour, and if they are small, then the number goes into hundreds.
Each stone is looked at three times.
Manual diamond weighing
The weight of a diamond is determined in carats. The name “carat” comes from the seed of the carob tree, carat.
In ancient times, the carat seed served as a unit of measurement for the mass and volume of precious stones.
1 carat – 0,2 g (200 mg)
Stones weighing more than 50 carats are found several times a month.
The largest diamond on the planet, the Cullinan, weighs 621 grams and costs about 200 billion rubles.
The largest diamond among the Yakut ones is the “XXII Congress of the CPSU”, it weighs 342 carats (more than 68 grams).
In 2013, ALROSA Group enterprises produced more than 37 million carats of diamonds.
Of these, 40% goes for industrial purposes and 60% for jewelry.
After selection, the stones go to the cutting plant. There diamonds become diamonds.
Cutting losses range from 30 to 70% of the weight of the diamond.
As of 2013, the reserves of the ALROSA group amounted to 608 million carats, and the forecast reserves are about one third of the global total.
Thus, the company is provided with a mineral resource base for 30 years to come.
