Mine run
As a mine passage is referred to in the fortress brick-lined underground tunnels that stretch before the actual ramparts and should be blown up in the application. From an entrance, a main tunnel leads to the front, from which smaller branch tunnels branch off to the right and left. In the event that enemy soldiers are visible above the tunnel, it was first filled with explosives, then shut off the respective tunnels several times to dampen the explosion pressure and protect their own soldiers from thrown objects to then the explosives for detonation to bring . The above-ground enemies were killed in the event of a successful detonation. The tunnels were usually at least five meters deep in order to prevent enemy troops from entering the mine system via the resulting craters after a successful blast.
When fortress loops , most of the mine passages were often only blown up at junctions and their entrances, so that although they were impassable, they were usually still in the ground. As a result, remnants of forgotten mine passages are regularly found in building projects directly outside of the former fortifications, or that cellar cave-ins over these remnants sometimes occur. In rare cases, former mines are also planned by house builders so that they can be used as a wine cellar . However, the mine tunnels are too deep for burglaries under the roads built above.