Copper workings are still important today in the area of Mansfeld. The last centres of mining were the Rammelsberg near Goslar (closed 1988) and the Hilfe Gottes Pit near Bad Grund (closed 1992). In Bad Lauterberg, barite - used today primarily for the manufacture of paint and in sound insulation - was extracted until July 2007 at the Wolkenhügel Pit, the last mine in the entire Harz. Furthermore, limestone is still mined at Elbingerode in three large open pits (Werk Rübeland, Werk Kaltes Tal and Werk Hornberg). Another important employer is the Clausthal University of Technology. In addition to the classical disciplines of mining and metallurgy, many engineering and science subjects, as well as business studies courses, are taught and researched.