During the final mining period, the VII Lichtloch (air shaft) and its heap, set in the centre of the Muldental, was completely covered with waste produced by the Halsbrück mining industry, right up to the pithead. The mining settlement known as Grube Beihilfe, built in the late 1830s, is adjacent to the air shaft. A 591-metre-long motive-water leat carried water from the Roter Graben manmade ditch to the air shaft in order to power the water wheels and later the water column engines. The water-column engine proved not to be powerful enough, so it was replaced by a Schwamkrug turbine in 1868. This required an immense amount of motive water, and led to the cessation of ore transport on the ore canal. Underground, the staggered branches of the adit lead off from the VII Lichtloch (air shaft) to the Grube Beihilfe mine and the Churprinz Friedrich August mine. The Rothschönberger Adit changes direction at the VIII Lichtloch (air shaft). Some twenty or thirty metres past the air shaft, the Rothschönberger Adit becomes smaller in profile.