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Equipment selection is one of the most important factorsin open pit design and production planning. Equipment selection also affects economic considerations in open-pit design as a function of plan location and depth. Furthermore, equipment selection is a complex multiperson, multi-criteria decision problem. The group decision-making process can be improved by a systematic and logical approach to assess priorities based on the inputs of several specialists from different functional areas within the mine company. The analytic hierarchy process (AHP) can be very useful in involving several decision-makers with different conflicting objectives to arrive at a consensus decision. In this paper, the selection of a loading-hauling system using an AHP-based model was evaluated for coal production in an open pit coal mine located Orhaneli, in western Turkey. The use of the proposed model indicates that it can be applied to improve group decision making in selecting equipment that satisfies optimal specifications. Also, it is found that the decision process is systematic and that using the proposed AHP model can reduce the time taken to select optimal equipment. The author is in the Mining Engineering

Purpose. A methodology development for predicting the geomechanical situation when mining an ore deposit with steep-dipping layers, taking into account the uncertainty in determining the rock properties, which is a consequence of the rock mass heterogeneity. Methods. The assessment of the open-pit wall stability is based on a combination of numerical simulation of the rock stress-strain state (SSS) and probabilistic analysis. The finite element method is used to determine the changes in the SSS that occur at various stages of mining operations due to design changes in the overall open-pit slope angle. The elastic-plastic model of the medium and the Mohr-Coulomb failure criterion are implemented in the codes of the 3D finite element analysis program RS3 (Rocscience). Stochastic simulation is used to assess random risks associated with natural object state variations. Findings. The distribution of maximum shear strains, which localizes the real or potential sliding surfaces in the open-pit wall at various stages of ore mining, has been identified. Based on the Shear Strength Reduction procedure, the open-pit wall Strength Reduction Factor (SRF) has been determined. The probabilities of open-pit wall stability loss, as well as the decrease in the strength reduction factor below the standard level at all stages of the ore body mining, have been revealed. Originality. For the first time, for real mining-geological conditions of a deep ore open pit, the dependence of the strength reduction factor on the overall wall slope angle, which changes during mining of each steep layer, has been determined. For each stage of mining operations, for the first time, the probability of a decrease in the open-pit wall stability below the standard level has been determined based on stochastic simulation. Practical implications. The ratio between the open-pit contour characteristic (overall slope angle) and the probabilistic safety factor is the basis for practical solutions to ensure the efficiency and safety of mining at various stages of friable and hard overburden excavation, ore extraction, as well as for the subsequent optimization of the open-pit design contours.