Articles by Aydoğan AKBULUT

In open pit mining from the safety point of view it is very important that physical and mechanical characteristics of the dug-out materials are carefully studied, and geological and geotechnical characteristics should also be considered in planning bench slopes of the dug-out materials. The purpose of this study is to work out the stable slope geometry of the eastern permanent slopes in the K›fllaköy open pit lignite mine of the Afflin-Elbistan Linyit ‹flletmesi. In the K›fllaköy open pit mine, 35 geotechnical drillings totalling 3393.20 m were made for the geotechnical studies and to work out slope sizing. A total of 250 vertical electrical drillings (DES) were also made to study tectonic features and lithological changes which do not have surface expressions. All these data have been used in this study. Design analyses showed that black coloured clay bands with high plasticity present in between lignite horizon is the most important unit controlling slope stability. Slope stability analyses have in general been conducted using the ‘finite elements’ and the ‘limit equilibrium’ method to suit block sliding model and to suit different groundwater conditions. In the analyses for the stresses affecting the slices; central part of the slice has been taken as a base and the ‘finite elements’ stability studies have been conducted then the findings have been compared. According to this it is understood that if stresses affecting the slices are conducted by the ‘finite elements’ method then calculated factor of safety on the bench base would be more from 1% to 7%, and in the slope angles it would be more from 1% to 23%.

The subject of this study is to study the instabilities that have developed in the permanent east and west slopes of the Kışlaköy open pit of the Elektrik Üretim A.Ş. Afşin-Elbistan Linyitleri İşletmesi and to work out the sliding mechanism causing it. In the Kışlaköy open pit to establish if mass movement is continuing and if so which direction it would move, amount of mass to be involved and the failing model. Six movement control observations stations were established along 3 lines in each of west and east slopes. No movement was observed in the west slopes. On the other hand up to 90 cm cumulative movement was observed at the at D24 and D18 observation station on the east slopes. Measurements taken showed that there were failings in the lignite horizon fitting to the ‘block sliding model’. During the field study circular sliding model type failings were observed in the basal units. In the open pit in general before and after the sliding, plans were prepared of the instabilities to enable geometries could be worked out. By using these plans cross sections were prepared to show the geometry of the instabilities before it actually took place and retrospective analyses of the failing model have been carried out. Correlations have been made of the results of the retrospective analyses and resistance parameters obtained from the laboratories. It was concluded that during the movement of the mass, shear strength of the sliding planes were then represented by the shear resistance parameters. During the study it was found out that the black coloured clay band with high plasticity within the lignite horizon is one of the most crucial factors controlling slope stabilities.