The quantity of land affected in the extraction of lignite in opencast mines is vast. Former mining activities leave behind numerous mine voids, which will mostly remain as artificial lakes from rising groundwater and flooding. Overburden dumps are stretched over large areas. These areas present themselves as often uninhabitable and difficult areas for construction without further site investigation and understanding.
For the successful rehabilitation it is necessary to accurately determine the movements and deformations of the dump masses, that occur over time. The non-cohesive soils in particular, are susceptible to liquefaction when exposed to groundwater impact.
There is a requirement for the pit slopes and overburden dumps at the Central German Lignite District, which remain since 1990, to be secured to provide usable land. This enormous project asks for a scientific foundation based on planning and rehabilitation, as well as an engineering verification.
GUB AG is one of the consulting partners of the LMBV Ltd., the mining company which is the owner and responsible for the affected areas, it was their responsibility to come up with a solution to resolve the complex geotechnical problems and ensure the area becomes safe and parameters assessed, such that decisions can be made on how to stabilise the area for the future.