Aug 2, 2011: Images of the world's 10 largest excavations and natural chasms

Russian mining firm Alrosa runs not only the Mirny Mine, but also the Udachnaya pipe in the Daldyn-Alakit kimberlite field in Sakha Republic, Russia. Udachnaya was discovered on June 15, 1955, just two days after the discovery of the Mirny diamond pipe by Soviet geologist Vladimir Shchukin and his team. It is more than 600 metres (1,970 ft) deep, and is said to be the third largest open-cast mine in the world. Open-pit mining at the site was abandoned in 2010 in favour of underground mining operations.