Development and Implementation of an Innovative Sealing Concept for Smaller Shafts in Ore Mining
Author: Christian Grineisen, M.Sc., Sachtleben Bergbau Verwaltungs-GmbH, Lennestadt/Germany
In 2024, as part of exploratory work in the area of near-surface mining at the Meggen mine, a historic ventilation shaft was investigated using drilling techniques. The investigation revealed that the stepped shaft was partially backfilled with loose material in its near-surface section, while remaining open down to a depth of approx. 64 m. As the long-term structural stability of the initial condition could not be verified, a remediation method was developed to underpin the existing column of loose fill and to convert the shaft into a demonstrably stable condition by installing a permanently positionally stable sealing structure. Any potential impact on the hydraulic connectivity of adjacent mine levels at the shaft depth had to be avoided.
In collaboration with expert consultants and specialised mining contractors, a remediation concept was developed using a silicate foam-filled textile element, which was initially tested on a smaller scale. This approach enables the creation of a load-bearing abutment within the shaft using only a limited number of boreholes, upon which the required cohesive fill section can be constructed.
The method has now been successfully tested on two shafts. In the future, it will allow for the efficient and rapid sealing of smaller shafts with minimal site infrastructure and low impact on the ground surface. Compared to conventional methods, resource consumption can be significantly reduced.
This article is based on the German-language version published in the proceedings of the 23rd Colloquium on Abandoned Mining of Clausthal University of Technology (DOI 10.21268/20250804-0).
