Performing the annual wall thickness measurements of the manhole pipelines located in the manholes 2 and 4 using the Multifinger measuring method.

The pneumatic conveying as well as the fluid conveying requires the operation and the maintenance of an over- and underground piping system, which is claimed by the different materials in the various stages of the Sorelbetonherstellung and removal of the access waters in various ways.

The manhole pipes in manholes 2 and 4 require special attention in terms of wear and tear according to the "Guidelines for the Construction and Operation of Manholes in Shafts of 30.6.2005" and must be checked regularly In this case, the multi-finger measuring method has proved its worth and the measuring results of the shaft pipelines are to be submitted to the State Office for Mining, Energy and Geology (LBEG) .The wall thickness measurements are to be commissioned as a call from a framework contract.