The Largest Open Pit Diamond Mine in the World
Nothing marks the presence of humans better than a massive hole in the ground (clear-cutting came a close second). Boring deep into the Earth for the love of riches and resources, we humans dig deep and often. In the town of Mirny in Eastern Siberia, lies the largest open pit diamond mine in the world. It’s also the second largest excavated hole in the world, second only to the Bingham Canyon Mine in Salt Lake City, Utah. Check out the incredible images below with facts littered throughout.
Mir Mine, also called Mirny Mine, is the second largest excavated hole in the world. It is 525 meters (1,722 ft) deep and 1,200 meters (3,900 ft) wide. The hole is so big that even the airspace above the mine was closed to helicopters as there were several incidents of them being sucked in by the downward air flow.
HOW IT ALL STARTED
The mine was discovered on June 13, 1955 by Soviet geologists Yuri Khabardin, Ekaterina Elagina and Viktor Avdeenko. They found traces of volcanic rock kimberlite which are usually associated with diamonds. This finding was the first success in the search for kimberlite in Russia, after numerous failed expeditions of the 1940s and 1950s. For this discovery, in 1957 Khabardin was given the Lenin Prize, which was one of the highest awards in the Soviet Union.
The development of the mine had started in 1957 in extremely harsh climate conditions. Seven months of winter per year froze the ground into permafrost, which was hard in winter, but turned into sludge in summer. Buildings had to be raised on piles, so that they would not sink in summer, and the main processing plant had to be built on a better ground found 20 km away from the mine.
The winter temperatures were so low that car tires and steel would shatter and oil would freeze. During the winter, the workers used jet engines to defreeze and dig out the permafrost or blasted it with dynamite to get access to the underlying kimberlite. The entire mine had to be covered at night to prevent the machinery from freezing.
WELCOME TO THE DIAMOND LIFE
In the 1960s the mine was producing 10,000,000 carats (2,000 kg) 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 g) per tonne of ore, with the relatively high ratio of gems to industrial stones. The yield decreased to about 2 carats (0.40 g) per tonne and the production rate slowed to 2,000,000 carats (400 kg) per year near the pit bottom.
The largest diamond of the mine was found on 23 December 1980; it weighed 342.5 carats (68 g) and was named “26th Congress CPSU”. The mine operation was interrupted in 1990s at a depth of 340 m after the pit bottom became flooded but it eventually resumed.
The Mir mine was the first 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. Currently, the mine is operated by Alrosa, the largest diamond producing company in Russia, and employs 3,600 workers.
It had long been anticipated that the recovery of diamonds by conventional surface methods would saturate. Thus, in the 1970s, construction has started on a network of underground tunnels for diamond recovery. Production of diamonds by this method started in 1999 and is estimated to last for another 27 years. This estimate is based on depth explorations down to 1,220 meters. In order to stabilize the abandoned main pit, its bottom was covered by a rubble layer 45 meters thick.
See that red arrow on the right about mid-way down? That’s pointing to a 220-ton hauling truck that’s over 20 feet tall!
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