The purpose of the work. Investigation of the manifestations of rock pressure in the retractable road of a steep coal seam to ensure the operational state of production and increase the safety of work at the excavation site of a deep coal mine. The research used a comprehensive approach, including analysis and generalization of theoretical and experimental research on this problem, field experiment to study the stability of retractable drifts and processing of experimental data. To assess the stability of the preparatory workings, mine studies were performed to study the manifestations of rock pressure in the retractable drift under different methods of protection, when the magnitude of the displacement of lateral rocks on the contour and change the cross-sectional area of the drift along the excavation section. As a result of the performed researches the conditions of stability of retractable drifts of steep coal seams at protection by fires from wooden sleepers and bushes from risers are substantiated. It is recorded that in the zone of influence of mining works, the fastening in the retractable road is deformed and has characteristic curves from the roof. At a distance of l > 80 m behind the clearing face, the loss of the cross-sectional area of the excavation was about 50 % with the method of protection by bushes from the risers and 30 % with the use of wooden fires. It is experimentally proved that with the method of protection of precinct preparatory workings by rigid wooden structures in the form of bushes from risers, the change of cross-sectional area of the retractable lane behind the treatment face in the area of impact of treatment works occurs linearly with increasing length of the excavation site. To ensure the stability of retractable drifts in a deep coal mine with a steep occurrence of coal seams, it is advisable to use aimless methods of protection, when to support the side rocks are used pliable structures in the form of fires made of wooden sleepers. The use of this method of protection of the preparatory workings can reduce the likelihood of landslides and increase the safety of mining operations.

Purpose of work. Investigation of maingates stability in different methods of protection on the extraction layouts of a deep coal mine, which develops steeply inclined coal seams. Methods. To achieve this goal, mine experimental observation of maingates stability performed. Conditions for their maintenance are evaluated by the magnitude of the convergence of the side rocks on the contour and changes in the cross-sectional area of the gateroads. Results. As a result of the research the conditions of maingates stability in steep coal seams in protection by pillars or timber sets are substantiated. It is recorded that in the zone of influence of extraction operations, at a distance of l <60 m behind the mining face with the considered methods of protection, the support of the maingates is deformed within the yielding limits and has characteristic flexures the side of hanging wall. At a distance of l≥60 m, the cross-sectional area of the maingates is reduced to 50% of the initial values, and the amount of roof to floor convergence exceeds the flexibility of the support. The increase displacement of rock mass on the contour of the supported roadway behind the mining face depends on the strength and geometry of the secondary support structures above the maingate. Novelty. It is experimentally established that the change in the cross-sectional area of the maingate during protection by timber sets occurs linearly with increasing length of the extraction layout. Practical significance. To ensure the maingates stability, it is advisable to use non-pillar methods of protection, when using yielding secondary support systemsabove the roadway, or backfilling.

Purpose of work. Determine the conditions of the side rocks stability in a coal massif with different ways of support coal-rock stratum to ensure safe working conditions for miners in the excavation areas of a coal mine with steep coal seams. To achieve this goal, laboratory studies were carried out on models of optical and equivalent materials. The modeling of the stability of side rocks in a coal-rock massif was carried out with the methods of support roadways with vertical timber setsand wooden crib supports: 4-point chock.On models made of optical materials in the analysis of the static field of the distribution of shear stresses in side rocks, the regularity of the change in hazardous manifestations of rock pressure, depending on the deformability of support structures, was recorded. On equivalent models of support structures, the deformation characteristics of experimental samples were determined and their effect on the integrity of the roof under the action of static loads was established. When using rigid support structures in the form of vertical timber sets made of wooden racks to protect sliding drifts, there is a deterioration in the stability of side rocks and destruction of the roof. When using flexible support structures in the form of wooden crib supports: 4-point chock, a smooth deflection of the roof and its integrity are observed. A decrease in the size of the stress concentration zone in the model of a coal-rock massif with workings after the compaction of flexible support structures located above the haul roadway, due to a change in their rigidity, when as a result of the convergence of side rocks, a smooth deflection is provided and the movement of the roof is limited. To ensure the stability of side rocks and development workings, as well as reduce the level of injuries of miners from landslides and collapses in the excavation areas of coal mines that develop steep seams, it is advisable to use flexible support structures, when using which, a smooth deflection of side rocks and their integrity in the mined-out area is ensured coal massif.

Purpose. To assess the production risk of rock collapse in a deep coal mine to identify hazards in the workplaces of the excavation site, taking into account different methods of protection of workings. Methods. A comprehensive approach was used, which included: analysis and generalization of known research; expert evaluation; use of the basic provisions of probability theory and set algebra (Venn diagrams), the method of estimating the production risk of Fine-Kinney; processing, analysis and interpretation of the obtained results. Results. Problems and sources of industrial risk from rock collapses during maintenance of workings, risk-forming factors that contribute to the threat of dangerous events at the excavation site are analyzed. The decision-making model is considered, which is based on the description of situations when the production risk of the dangerous factor “landslides and collapses” in the maintenance of preparatory workings depends on the result of choosing an alternative method of protection of the retractable lane. For excavation sites under the same mining and geological conditions for all workplaces, the probability of receiving consequences from dangerous events due to uncertain conditions of their implementation has been established. It is fixed that the realization of this production risk is influenced by low reliability and inefficiency of the practiced methods of protection of excavations. Risk analysis is defined as the systematic use of available information to identify hazards in the maintenance of long workings. Novelty. A model for monitoring the production risk of rock collapses in excavations of deep coal mines is proposed, which allows assessing the dynamics of the threat at the stage of technical decisions related to the choice and justification of the method of protection of workings taking into account the interaction of risk factors. Practical significance. When formulating measures to reduce the risk of dangerous events at the excavation site, it is necessary to take into account that the production risk of rock collapse while maintaining the workings depends largely on the method of protection and effectiveness of technological measures.

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