Material requirements: Large quantity and high density
In the summer of 2011, shifts were observed on various pillars on which the ski hall was built due to the subsidence of the mining pile, which made it necessary to discuss the problem in the planning committee of the city of Bottrop. A solution had to be found in order to ensure the continuity of the alpincenter. Different scenarios for the stabilisation of the underlying pile slope by a backfill against the direction of displacement were designed.
The great challenge lay in the selection of a suitable construction material that is technically suitable and sufficiently available to fill a volume of 450,000 cbm.
With the support of REMEX GmbH, a sustainable concept was developed for the alpincenter at the end of 2015. By combining IBA incinerator bottom ash of the granova® brand produced by REMEX at the Oberhausen site with iron silicate sand, a by-product of the copper recycling at AURUBIS, a mineral construction material is produced that more than meets the technical requirements for stability, water permeability and bulk density.
The advantages of the material with regard to availability, high homogeneity and stable quality, ensured by regular quality monitoring by REMEX and AURUBIS, were the determining factors in this decision compared to a version using soil. This concept convinced not only the city of Bottrop as authorising body, but also the Ministry of the Environment in Düsseldorf and the Münster district government.
Since autumn 2016, a structure is under construction which, with safety standards from landfill construction, guarantees a sustainable stability of the mining pile. An expert office in Essen regularly inspects the structure, all processes are documented in detail and made available to the authorities.