(in Russian, shakhta), a mining enterprise that extracts minerals by underground methods and ships them to a consumer or an ore-enrichment plant. An underground mine includes both surface structures—for example, headframes, headhouses, and storehouses—and all the underground mining excavations that are used to work a deposit within a mine area. Such a mine is a mechanized and automated enterprise equipped with efficient machinery and devices for the extraction and hauling of minerals, for the sinking of mining excavations, for the removal of mine water, and for ventilation. Underground mines that work large deposits have lives of 50–70 or more years.
The largest underground coal mine in the USSR is the Raspadskaia Mine, which is in the Kuznetsk Coal Basin and has a projected eventual output of more than 7 million tons a year. The largest underground iron mine in the USSR is the Gigant Mine, which is in Krivoi Rog and has a projected eventual output of 12 million tons a year. The deepest underground mine in the USSR is the Academician A. A. Skochinskii Mine, which is in the Donets Coal Basin and is 1.2 km deep.
The deepest underground mines in the world are gold, silver, and diamond mines; they are 4–4.5 km deep. They include the Champion Reef gold mines in India and the Witwatersrand gold mines in the Republic of South Africa.