Udachny
Udachny is a town in Mirninsky District of the Sakha Republic, Russia, located on the Markha River, from Mirny, the administrative center of the district. As of the 2010 Census, its population was 12,613.
History
The Udachnaya pipe diamond deposit was discovered in 1955. Due to its isolated location, it was not exploited until the 1960s. In conjunction with the beginnings of diamond production, the urban-type settlement of Udachny was founded in 1968; town status was granted to it in 1987.As part of a plan to create the basin for a tailings dam for the nearby diamond mine, a 1.7 kiloton atomic bomb was detonated underground near Udachny on October 2, 1974. Original plans had called for eight similar explosions to be conducted; however, due to radioactive fallout being far greater than expected, the project was halted after the first blast. The shaft in which the explosion was held was not plugged until eighteen years later, with an estimated thick concrete sarcophagus.