Mirny Mine

The Mir mine, also called the Mirny mine, is an open pit diamond mine located in Mirny, Sakha Republic, in the Siberian region of eastern Russia. The mine is more than 525 meters deep, has a diameter of 1,200 m, and is one of the largest excavated holes in the world.

Open-pit mining began in 1957 and was discontinued in 2001. Since 2009, it has been active as an underground diamond mine.

Source: Wikipedia