The Mir mine, is an open pit diamond mine located in Mirny, Sakha Republic, in the Siberian region of eastern Russia The mine is 525 meters deep (4th in the world) and has a diameter of 1,200 m, and is one of the largest excavated holes in the world. 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 from the warmth of the building melting the permafrost. 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 tires and steel would shatter and oil would freeze. During the winter, workers used jet engines to thaw 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.Diameter of circle 1130 meters62.527910, 113.995069