The chamber lies directly above the Old Main Shaft has been protected with cribs and close-set timbering. In it's central part is the horse-operated treadmill of an ancient type a wooden machine, which was used to haul ore and people from the lower to upper floors via the Old Main Shaft. The treadmill could haul up to two tons of ore.
The device consists of a vertical shaft with a rope drum, four tractive arms with a bridle for the horse and a shoe-brake with steering levers. The most important part is the device with two wheels which changes the movement of the rope from horizontal to vertical direction.
The wooden mechanism was maintained and still used to allow quick access to other sections of the Old Mines, while it lacks motive power, and a few elements have decayed, it can easily be restored to functioning.
There are two entrances to this room, one door along the west wall and a sloping tunnel along the east wall