Causes, mechanism and environmental impacts of instabilities at Himmetoglucoal mine and possible remedial measures

Since the commencement of mining at the Himmetoglu coal mine, northwest Tur key, serious stability problems have led to interruptions in mining and som e environmental effects. A geotechnical investigation was initiated in 1997 and the significant factors that influence the stability have been defined . This paper outlines the results of the field and laboratory studies assoc iated with the causes and mechanism of the slope instabilities and their en vironmental impacts. The possible remedial measures to improve the stabilit y and to minimize the environmental problems are also described. Back-analy ses and data from long-term monitoring indicate that the failures occur alo ng two or three planar surfaces by combination of faults and localized stra ta steepening adjacent to the faults. The stability is sensitive to changes in length of the lower part of the basal sliding surface and shear strengt h of the bedding surfaces in the overburden. Suitable remedial measures inc lude slope flattening (i.e. staged bench stripping), proper drainage and sp reading of a rock blanket on the pit floor to increase spoil pile stability .