At the end of 2000, rock mining at the Werdenfels hard stone works, for a long time the largest plant of its kind in Bavaria, was stopped after more than 70 years. In the same year, the Murnau Castle Museum took this as an opportunity to hold a special exhibition to not only document the eventful history of the quarry operation at the Langen Köchel, but also to present the accompanying conflicts with nature conservation that led to the cessation of rock mining. In the middle of the Murnauer Moos nature reserve, rock hills ("Köchel") rise up, which were formed in the Cretaceous period 100 to 200 million years ago and consist of extremely hard rock, glaucoquartzite. The quality and extremely rare occurrence of glaucoquartzite in Bavaria, which was found to be suitable for civil engineering during investigations in 1926, led to two rock mining areas in the Murnauer Moos. The Werdenfels hard stone works (HWW) began operations in 1930 at Langen Köchel. Even in its early years, the works had a high technical standard. The abundance of glaucoquartzite deposits and the unrivalled location ensured that the company had road and river construction authorities, municipalities and construction companies as clients. The then Reichsbahn in particular was a major customer for its gravel requirements. A change of ownership in 1947 enabled new financing and allowed the works to expand its position in the hard stone industry. A lot was also done for the workforce: in the 1950s, a new canteen was built at the quarry and a housing development was built in Eschenlohe. In 1981, the works was taken over by the Essen-based construction company HOCHTIEF. The works were modernized with new technology and, despite their location in the Murnauer Moos and the ongoing disputes with nature conservationists over a new mining site, they were run profitably. In 1994, the hard stone plant lost the decisive administrative court case and ceased operations at the end of 2000.