The Thurm Rosenhof Mine is one of the oldest mines in Clausthal and was one of the longest in operation. The Rosenhof ore vein was where mining in Clausthal developed. The mine was operated continuously from the beginning of the 16th century right up to the 20th century. The large amount of waste stone from the mine that was piled up around the mine's bidirectional water wheel threatened to bury it. So it was decided to protect it with a ring wall. As the waste heap grew, so did the ring wall - finally to a height of 24 m. An above-ground building thus became an underground building.