Diamonds were formed more than 300 million years ago. Kimberlite magma formed at a depth of 20 or 25 km. Magma gradually rises along faults in the crust and when the upper layer can no longer hold back the pressure of the magma, an eruption occurs. The first such “pipes” were found in Kimberley inSouth Africa and from there came the name. In the mid 50s rich primary diamond deposits were discovered in Yakutia. Here the diamonds were found in about 1500 kimberlite pipes.
The Russian company “ALROSA” produces 99% of diamonds in Russia and more than 25% of the diamonds in the world .
The kimberlite pipe “Mir” (Peace) is an indigenous diamond mine that had been opened in 1955. The field was developed initially at Mirny where an open pit mine and processing plant were created. The quarry has a depth of 525 m and a diameter of 1.2 km, so it is one of the largest in the world. Diamondiferous kimberlite ore open pit mining ceased in June 2001. Since 2009, mining diamond ore is done in the “Mir” underground mine.
City of Mirny – the diamond “capital” of Russia, located in Yakutia. It is 1200 km from Yakutsk.
The population is 35000 people.
Lenin’s Square is the center of the city.
The headquarters of Russia’s largest diamond company “ALROSA” is also situated in Mirny.
The company started with a trust called “Yakutalmaz”, formed for the development of indigenous diamond deposits in Yakutia in the early 1950s.
The quarry is located close to Mirny.
Diamonds worth U.S.$17 billion were extracted from the quarry between 1957 and 2001.
The mine employs about 760 people.
The company operates seven days a week. Mining operations run over 3 shifts, each shift lasts 7 hours.
9 tunnelling machines are involved in working the mine (Sandvik MR 620 and MR360).
And 8 Scooptrams.
The length of the backbone conveyor belt is 1200 meters.
The average diamond content is more than 3 carats per tonne.
The mine has a water collection system: at first groundwater is collected in special lagoons, and then routed to the -310 meters mark by the pumps, and then finally pumped to the surface.
This is the underground work in another drive, called “International” (“Inter”).
It is located 16 km from Mirny. Diamond mining by the open cut method started here in 1971, and in 1980, when the quarry reached a depth of 284 m, it was mothballed.
The “International” has the richest diamond content – more than 8 carats per tonne.
The shaft depth is 1065 meters. The drive reaches to a length of 1220 meters.
The length of all the workings here is more than 40 km.
The cutting machine loosens the ore by means of teeth installed on the roller cutter.
Next comes it’s loading on Scooptrams.
On average, one ton of “Inter’s” rock contains 8.53 carats of diamonds.
The mine operates 24 hours a day, 7 days a week. Only two holidays are celebrating there – New Year and Miner’s day.
Nyurbinsk GOK was established in March of 2000 to explore the Nakyn ore field (Yakutia) for kimberlite pipes “Nyurbinskaya” and “Botuobinskaya”, as well as adjacent placers. The mine is an open cut mine.
On July 1, 2013, the depth of the quarry “Nyurbinsk” was 255 meters.
Open pit mining will be practiced until a depth of 450 meters (to the level of -200 meters above sea level) is reached. There is a potential to reach -320 meters.
To transport the ore and the overburden dump heavy-duty vehicles are used – from 40 to 136 tons.
The average content of diamonds in the ore – 4.25 carats per tonne.
There are 300-400 carats in the back of the truck.
The ore is delivered to the crusher.
The the stones are separated into groups.
X-ray separators. These separators are using the property of diamonds to glow in X-rays. The material moves along the chute and is irradiated with X-rays. While in the radiation zone, a diamond glows. After the flash a special device captures the glow and sends a signal to shut off the device.
There are no ideal or identical diamonds in nature, so their classification involves sorting.
16 sizes x 10 grades of 5 qualities x 10 colors = 8000 positions.
The small ones are sorted by weighing machines. Large diamonds are sorted by people.
1 carat – 0.2 grams (200 mg)
Stones weighing more than 50 carats are found only a few times a month.
The world’s largest diamond “Cullinan” weighs 621 grams and it’s worth is about 200 billion rubles.
The largest diamond of Yakutsk – “XXII Congress of the Communist Party” weighs 342 carats (over 68 grams).
In 2013, the “ALROSA” group reserves were about 608 million carats.
Thus, the company is provided by the mineral resource base for 30 years.