Formerly the Soviet Union ’ s largest diamond mine , the Siberian Mir mine is one of the biggest excavation pits on the planet and is credited as having been the keystone of the Soviet diamond industry . The open-pit mine was operational from 1957 to 2001 , closing officially in 2004 , before reopening in 2009 with operations shifted below ground . It is estimated to have produced US $ 17bn ’ s worth of rough diamonds by its 2001 closure . Now operated by Alrosa , Russia ’ s largest diamond company accounting for 95 % of the nation ’ s diamond output , the mine is capable of yielding 2,000kg of diamonds per year . Having reopened in 2009 , the mine is predicted to remain operational until around 2059 . The mine is certifiably enormous , cited as one of the largest excavated holes on Earth , with the open pit reaching a depth of 525m with a diameter of 1.2km .

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By Staselnik – Own work , CC BY-SA 3.0

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