View article

In February 2011, two landslides in which 11 people were killed, occurred in the Çöllolar open pit mine, situated in the Elbistan Basin in eastern Turkey. In the coalfield, a thick sequence of clay (>100 m) overlies karstic limestone bedrock. These are overlain by deposits consisting of a 20–50 m thick lignite sequence and a 20–50 m thick gyttja sequence. The gyttja is in turn overlain by Quaternary deposits. In this study, we aimed to shed light on the geologic factors that led to the instability and on the precise trigger for the failure. Therefore, we focused on the above Plio-Quaternary lacustrine and fluvial sediments and applied geomorphological, sedimentological, and geotechnical analyses. After establishing the geomorphology of the coalfield and the landslides, we analyzed 38 samples from existing drill cores, 10 surface samples, and 35 undisturbed samples from new boreholes. Our results indicate that the …