Stability and characterisation of spoil heaps in European surface lignite mines: a state-of-the-art review in light of new data

• Published in: Environmental earth sciences Vol. 78; no. 16; pp. 1 - 18
• Main Authors: Masoudian, Mohsen S., Zevgolis, Ioannis E., Deliveris, Alexandros V., Marshall, Alec M., Heron, Charles M., Koukouzas, Nikolaos C.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.08.2019; Springer Nature B.V
• Subjects: Biogeosciences; Case histories; Constitutive models; Earth and Environmental Science; Earth Sciences; Economics; Environmental liability; Environmental Science and Engineering; Failure mechanisms; Geochemistry; Geology; Geotechnical engineering; Hydrology/Water Resources; Liability; Lignite; Mathematical models; Mines; Natural slope; Ocean dumping; Original Article; Slope; Soil properties; Spatial variability; Spatial variations; Spoil; Stability; Stability analysis; State-of-the-art reviews; Terrestrial Pollution; Time dependence; Slope stability; Open-cast mining; Spoil; Geotechnical characterisation; Brown coal; Mining waste
• ISSN: 1866-6280; 1866-6299
• DOI: 10.1007/s12665-019-8506-7

The large amount of spoil material produced during the mining process imposes a significant economic and environmental liability on lignite producers. In this context, the present paper provides an overview of the geotechnical characteristics of European lignite mine spoil heaps and discusses their significance to the stability of the heaps. In order to achieve this, samples collected from spoil heaps of Polish, Czech and Greek mines are analysed and the results are compiled with data from the literature. A major conclusion drawn is that both physical and engineering properties of spoil heaps indicate a noteworthy variability, which is larger than typical in situ ground material. This is because of the additional factors affecting spoil heap deposition, such as the transportation and dumping method. Furthermore, failure mechanisms and case histories of large instabilities in lignite spoil heaps are critically discussed in order to better understand triggering failure mechanisms. It is concluded that classical assumptions made for natural soil slopes and relevant limit equilibrium models should be cautiously applied to spoil heaps. The challenges associated with numerical and probabilistic modelling of spoil heap stability, such as the inherent spatial variability of spoils and the time-dependent changes in their geotechnical properties, are also critically discussed. Finally, important research gaps in design and analysis of spoil heap stability, such as the absence of appropriate constitutive models developed specifically for spoil materials, are summarised.