Purpose. Substantiation of the conditions for haulage drifts stability using different protection methods in steeply dipping seams based on a set of experimental studies. Methods. To achieve the purpose set, mine instrumental observations have been performed to study the rock pressure manifestations in zonal advance workings adjacent to the stope face on the haulage horizon. The conditions for their maintenance, within the mining site, are assessed by the side rocks convergence value on the drift contour and the change in the cross-sectional area, taking into account the deformation properties of the protective structures. Findings. It is recorded that in the zone of the stope works influence, in the most difficult conditions, haulage drifts are maintained, when coal pillars or clumps of prop stays are used for their protection. It has been determined that a decrease in the section of such mine workings up to 50% is the result of the protective structures destruction. When protecting the hau-lage drifts with the rolling-on chocks, a decrease in the mine working section up to 30% occurs in the process of the protective structures compression. It has been revealed that deformation of coal pillars or clumps of prop stays up to 10-20% leads to a loss of their stability, and an increase to 60% leads to a complete loss of their load-bearing capacity, intensification of rock displacements on the mine working contour and deterioration of its stability. It has been determined that in the process of deformation of the rolling-on chocks from sleepers by 20-60%, they are compressed without loss of load-bearing capacity, which ensures a smooth deflection of the overhanging stratum and restriction of rock displacements on the haulage drift contour. Originality. To study the deformation characteristics of protective structures above the drift, the function of the increment is used of side rock displacements on the haulage drift contour along the mining site length dependent on the relative deformations of protective structures, which makes it possible to assess the real dynamics of the process. Practical implications. When mining steep coal seams, using the specificity of geomechanical processes, which are manifested in an anisotropic coal-rock mass during unloading, satisfactory mine workings stability can be ensured by changing the deformation properties of protective structures above the drift.

The purpose of the work. Studying the stability of haulage drifts of steep coal seams with the method of protecting coal by pillars. An integrated approach was used as research methods, including: a full-scale experiment, analytical studies, interpretation of the results obtained. To assess the durability of mine workings, full-scale experiments were carried out to study the manifestations of rock pressure in the haulage drifts with the method of protecting coal by pillars, when the magnitude of the change in the cross-sectional area and the convergence of side rocks on the contour of the development workings along the length of the excavation section was established. It is fixed that at the maximum relative deformation of coal pillars (ε ≈ 0,7), the loss of the cross-sectional area of the haulage drifts at a distance of l ≥ 60 m behind the working face is more than 50 %, which does not correspond to the operational state of the workings. When studying the deformation properties of protective structures, it was found that after their deformation by 10–20 %, an increase in the convergence of side rocks in the haulage drifts begins, a distortion of the shape and loss of the bearing capacity of coal pillars. The distortion of the shape of the security structures contributes to the intensification of the displacements of the roof on the contour and is accompanied by a deterioration in the durability of the haulage drifts in the excavation areas of the coal mine. It has been proved that on a steep drop, with the method of protecting the haulage drifts with coal pillars, the change in the cross-sectional area of the excavation occurs along a linear relationship with an increase in the length of the excavation section due to the distortion of the shape and loss of the bearing capacity of the security structures. To improve the safety of miners in the excavation areas of coal mines developed steeply falling coal seams, it is recommended to abandon the method of protecting the haulage drifts with coal pillars. To avoid emergencies associated with the collapse of the roof, it seems advisable to use purposeless methods of protection – flexible structures or backfilling of the goaf.

Purpose of work. The purpose of the research is to determine the conditions for ensuring the stability of mine workings in the coal massif under the action of shock loads. Methods. To achieve this goal, analytical studies were performed using the basic provisions of classical mechanics and the theory of elasticity. In laboratory studies, experimental samples of crushed rock were used, which were placed in a steel cylinder. Results. In the course of experimental research, the influence of the impact force and the impact pulse of the falling load on the response of the plane on a pliable basis with inhomogeneous, piece-sized, fragmented rock was studied. It is recorded that at a constant amount of energy of a single impact (mgH = 14.7 J), when the height of the fall of the load decreases 3 times (from H = 1.5 m to H = 0.5 m), and the mass increases from m = 1.0 kg to m = 3.0 kg, the magnitude of the impact force is reduced by 50%. With an increase in the amount of energy of a single impact (from mgH = 4.9 J to mgH = 44.1 J) at the same height of fall, when the mass of the load increases threefold, there is an increase of 2.5 times the impact force. At a constant amount of energy of a single impact (mgH = const), the displacement of the plane on a pliable base of crushed rock depends on the magnitude of the impact pulse of the falling load. Novelty. It is proved that when there is collapse of lateral rocks in the coal massif containing the production, the force of impact on the surface is proportional to the time of fall of the rock blocks to the time of their impact interaction with the plane. Practical significance. In deep coal mines, as a result of mining and the probability of shock loads from landslides, to ensure the stability of mine workings in excavation sites, it is advisable to use pliable supports or filling the produced space with crushed rock, which will ensure the integrity of lateral rocks.

Purpose. Evaluate the stability of lateral rocks in the coal massif containing the workings, with introduce count the deformation characteristics of security structures. Methods. To achieve this goal, laboratory studies of the deformation characteristics of security structures located between the simulated roof and the sole of the coal seam, which were subjected to uniaxial compression. Results. It is proved that the deformation characteristics of protective structures affect the stability of lateral rocks in the coal massif containing the workings. The nature of the deformation of security structures under the action of external forces is determined by their rigidity. All other things being equal, when the roof and sole rocks have a constant bending stiffness, their stability depends on the rigidity of the supporting structures and the direction of the load applied in the tangential (wooden cogs, rolling cogs) or radial (riser bushes) direction. For the simulated security structures with an increase in the compressive load, a simultaneous linear increase in their stiffness and deformation modulus is recorded. Moreover, for wooden pillars, when the load is applied across the fibers, the clamped struts of wooden structures are compacted, as a result of which the convergence of the lateral rocks is limited. There is no such pattern for rigid structures in the form of bushes made of wooden risers. After the loss of stability of the protective structure, the modulus of deformation decreases, which is accompanied by an increase in the convergence of the side rocks to the complete destruction of the structure. It is recommended to abandon the rigid and at the same time fragile protective structures designed to support the side rocks. Scientific novelty. The stability of the roof in the carbonaceous massif containing the workings is estimated by the maximum relative deformation of the supporting structures as a result of uniaxial compression using a coefficient characterizing the ratio of the rigidity of the working protective structure and bending stiffness of the side rocks. Practical significance. To ensure the stability of the side rocks in the coal massif and the operational condition of the workings adjacent to the clearing face at the extraction site of the coal mine, it is necessary to focus on the use of flexible structures.