Friction Prop with Van Wersch Cap

Rubbing stamps were used underground to support the "ceiling" (mined: 'hanging'). These reusable supports consisted of two metal tubes. They could give way a little without breaking when the slope sank.

Interesting facts about mining on the tour, in beautiful surroundings 🌲🌳🍃🍁💚

"... Longwall lining is the term used in mining to describe all types of lining that serve to keep the hanging wall between the working face (coal face) and the offset edge free of rock that breaks away.
In the case of single ram removal, the longwall is supported by several individual rams in connection with caps. Instead of wood as the finishing material, iron is used here as the finishing material. Discarded railway tracks were initially used as caps, later in special constructions such as the 👉 van Wersch cap. The use of steel rams can increase the distance to the face of the mine, which makes it possible to keep the face of the mine free of rams. This has the advantage that extraction machines such as coal plows or shearer loaders can now be used. The development of the stamp went from various friction stamps to hydraulic stamps. ..."
de.wikipedia.org/wiki/Strebausbau