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RWTH Aachen University, Department of Engineering Geology and Hydrogeology, Lochnerstraße 4–20,52064 Aachen, Germany (kempka{at}lih.rwth-aachen.de)
Underground mining causes costly subsidence damage world-wide. In the 1980s German mining research developed stowage techniques using mining wastes during longwall mining operations. These were applied successfully, but not continuously because of economic considerations at that time. A combined technique for subsidence reduction, mining waste disposal and CO2 storage is being developed within the study presented. Oedometer tests conducted on pumpable mining waste suspensions with various moisture contents reveal useful compression characteristics making them suitable for stowing materials in excavated areas. Laboratory CO2 adsorption experiments on these wastes show remarkable CO2 sorption capacities in comparison with residual coal seams. The combination of CO2 storage and subsequent stowage can lead to a cost-effective way of subsidence reduction determined by the growing prices of CO2 emission certificates and restricting regulations with regard to CO2 emissions.
