A salt mine is an operation involve in the extraction of salt from rock salt or halite, a type of evaporitic deposit. Areas known for their salt mines include Khewra in Pakistan, Tuzla in Bosnia, Wieliczka and Bochnia in Poland, Hallstatt and Salzkammergut in Austria, Rheinberg in Germany, Slănic in Romania, Provadiya in Bulgaria, Avery Island in Louisiana, the wich towns of Cheshire and Worcestershire in England, and the Detroit Salt Company's 1,500-acre (10 km²) subterranean complex 1,100 feet (340 m) beneath the city of Detroit. The Sifto Salt Mine in Goderich, Ontario Canada is one of the largest salt mines in the world. It measures 1.5 miles (2.4 km) wide and 2 miles (3.2 km) long.