Purpose. The purpose of the article is to assess the risk of loss of stability of the preparatory mine workings in order to adjust measures to prevent hazards and their consequences in the excavation areas of a coal mine with steep seams.. Method. An integrated approach was used, including: analysis and synthesis of known studies, expert evaluation, application of the basic principles of probability theory, processing, analysis and interpretation of the results. Results. During the examination of 7 objects (excavation sites), the a priori ranking identified significant factors that affect the loss of stability of preparatory mine workings. Accidental events were considered: the collapse of the roof, the slippage of the sole in the produced space of the coal massif, and the failure of fastening in the roll-back stretch. The ranking results are confirmed by the concordance coefficient (0,9). The analysis of accidents related to the loss of stability of the preparatory workings with different methods of protection allowed establishing the frequency of roof collapses and ground slides in the coal massif at the excavation site. To statistically evaluate the failures of the arch support ω in the working face, field studies were carried out. It was found that in the area of influence of the cleaning operations when protecting the heading with coal blocks, the failure rate of the arch support is ω=0.24, bushes from the racks ω=0,27, and wooden fires ω=0,16. Taking into account the combination of the identified significant factors, the a posteriori probability of loss of stability of the heading in the area of influence of the longwall face in the area of 10 ≤ l ≤ 45 m is 0,036-0,055 m when using coal blocks, 0,044-0,078 bushes from the risers and 0,0176-0,036 wooden fires. The probability of arch support failure is approximately 0,6. On the basis of research, a quantitative assessment of the component risks wa established, which leads to the loss of stability of the rollback stretch. The maximum risk assessment R = 576 corresponds to the conditions when the production is protected by bushes made of wooden risers. Scientific novelty Assessment of the risk of loss of stability of the preparatory mine workings is a set of research and analytical measures aimed at reducing the manifestation of hazards in the coal massif at the excavation sections of a coal mine. Practical significance. To obtain qualitative and quantitative estimates of the risk of loss of stability of the preparatory mine workings along the length of the excavation section, a model of formation of a possible dangerous situation was proposed. Key words: coal mine, preparatory workings, cave-in, side rocks, simulation modelling, miners’ safety.
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