Lop Nur or Lop Nor (from a Mongolian name meaning "Lop Lake") is a former salt lake in China, now largely dried-up, located between the Taklamakan and Kumtag deserts in the southeastern portion of Xinjiang Uygur Autonomous Region in the People's Republic of China. Administratively, the lake is in Lop Nur township (罗布泊镇 pinyin: Luóbùpō zhèn, also known as Luozhong 罗中, pinyin: Luó zhōng) of Ruoqiang County, which in its turn is part of the Bayingolin Mongol Autonomous Prefecture. The lake system into which the Tarim River and Shule River empty is the last remnant of the historical post-glacial Tarim Lake, which once covered more than 10,000 km2 (3,900 sq mi) in the Tarim Basin. Lop Nur is hydrologically endorheic— it is landbound and there is no outlet. The lake measured 3,100 km2 (1,200 sq mi) in 1928, but has dried up due to construction of dams which blocked the flow of water feeding into the lake system, and only small seasonal lakes and marshes may form. The dried-up Lop Nur Basin is covered with a salt crust ranging from 30 cm to 1 m in thickness. Lop Nur has been used as a nuclear testing site, and since the discovery of potash at the site in the mid-1990s it is also the location of a large-scale mining operation.