Mir Mine

The Mir Mine is a former open pit diamond mine, now inactive, located in Mirny, Eastern Siberia, Russia. It’s approximately 525-meters (1,722-feet) deep (4th in the world) and has a diameter of 1,200-meters (3,900-feet), and is the second largest excavated hole in the world, after Bingham Canyon Mine. Continue reading for more fascinating facts about the world’s largest open pit diamond mine.

5. How it was Discovered

Mir Mine

The diamond-bearing deposits were discovered on June 13, 1955 by Soviet geologists Yuri Khabardin, Ekaterina Elagina and Viktor Avdeenko during the large Amakinsky Expedition in Yakut ASSR. They found traces of the volcanic rock kimberlite, which is usually associated with diamonds.

4. Frozen Ground

Mir Mine

The development of the mine started in 1957, in extremely harsh climate conditions. Seven months of winter per year froze the ground, making it hard to mine. During the brief summer months, the ground turned to slush. Buildings had to be raised on piles, so that they would not sink. The main processing plant had to be built on better ground, found 20 km away from the mine. The winter temperatures were so low that car tyres and steel would shatter and oil would freeze.

3. Insane Production

Mir Mine

In the 1960s the mine was producing 10,000,000 carats (2,000-kilograms) of diamond per year, of which a relatively high fraction (20%) were of gem quality. The upper layers of the mine (down to 340 meters) had very high diamond content of 4 carats (0.80-grams) per tonne of ore, with the relatively high ratio of gems to industrial stones.

2. Largest Diamond

Mir Mine

The largest diamond of the mine was found on 23 December 1980; it weighed 342.5 carats (68 g) and was named “26th Congress of the CPSU”. The mine operation was interrupted in the 1990s at a depth of 340 m after the pit bottom became flooded but resumed later.

1. The Closing

The Mir mine was the first developed and the largest diamond mine in the Soviet Union. Its surface operation lasted 44 years, finally closing in June 2001. After the collapse of the USSR, in the 1990s, the mine was operated by the Sakha diamond company, which reported annual profits in excess of $600 million from diamond sales.