In the eastern Harz Foreland (Mansfeld Land and Sangerhäuser Mulde) copper schist was mined until 1990. The early beginnings of this industry were first mentioned in 1199, and it was considered in its heyday, at the end of the 15th century, as the most important in Europe. In addition, at Ilfeld is the only stone coal mine in the Harz, the former Rabenstein Gallery Mine (Bergwerk Rabensteiner Stollen). In the North Thuringian mining area, there were numerous potash mines and, in the vicinity of Röblingen, geological waxes were extracted by a mining concern.