Slope stability assessment of the open pit albite mine in the Çine-Karpuzlu (Aydin) area

The study area is a open pit albite mine which has been operating by Çine Akmaden Company since 1996 and takes place in Aydın, Çine-Karpuzlu. 45 m thickness below the present base of the open pit in which only leucocratic orthogneisses are exposed, has been planned to be mined out. The scope of this study is to determine the optimum overall slope angle for different slope conditions at the time which the mining operations are terminated. In this context, according to detailed field investigation and laboratory tests performed on rock material, numerical studies were conducted.In numerical modelling, applicability of the finite element method (FEM) involving shear strength reduction (SSR) technique by considering the Generalized Hoek-Brown Criterion and Equivalent Mohr-Coulomb parameters to jointed rock slopes in the eastern part of the Alipaşa open pit was investigated. In this process, firstly five geotechnical cross-sections passing through the area affected from local block slides were taken; secondly stability analyses of overall slopes along these cross-sections considering the variations of Geological Strength Index (GSI), seismic acceleration (?s), slope angle (?slope) and water table location (WTL) were conducted using a two-dimensional software Phase2 V.7.013. The causes and mechanisms of slope instabilities, the factor of safety values for each cross-section were determined. The results obtained from each criterion were compared by statistical software SPSS (Statistical Package for Social Sciences) to determine the optimum overall slope angle in terms of the best fitting criterion for the orthogneisses.