Purpose is to develop and substantiate a mathematical model for forecasting of rock displacements around the development mine workings and optimization of techniques for their reinforcement. Methods. A comprehensive approach has been applied including numerical simulation; theoretical analysis; and experiments. Special attention has been paid to rock displacements based upon stress-strain state of the rock mass. The developed KMS-Ш software was used for the calculation helping model displacements and analyze the obtained data. Findings. Recommendations have been proposed to decrease a rock dilatancy coefficient achieved through correction of support parameters; mine working geometry; and control of rock deformation rate. It has been demonstrated that rock bolting use lowers significantly the intensity of the displacements. It has been identified that a decline in rock strength results in the increased failure zones; at the same time, the improved plastic properties minimize elastic energy accumulation reducing the displacement probability of the opposite crack surfaces. Originality. An algorithm has been developed forecasting displacements of the mine working peripheries taking into consideration the mining, geological, and engineering factors. A mathematical model has been represented to identify both elastic and non-elastic deformations in a border zone. The dependencies between border rock mass displacements, mine working depth, and rock strength have been defined. Practical implications. Determination of optimum parameters of rock strengthening helps minimize failure zones; better stability of mine workings; and reduce the possibility of dangerous geomechanical phenomena. Use of the proposed model makes it possible to improve mining efficiency owing to more accurate forecasting of displacements.

Purpose. To investigate the stress-strain state of the coal-rock mass surrounding a gob-side development roadway and to justify its support parameters under the mining conditions of the Karaganda Coal Basin. Methods. The study was based on geomechanical modeling of the coal-rock mass surrounding a roadway driven adjacent to the goaf of a previously extracted longwall panel and separated from it by a limited-width coal pillar. The simulations were performed in ANSYS using the finite element method in 2D. The computational model incorporated the goaf, protective coal pillar, stratified structure of the surrounding rocks, mining depth, physical and mechanical rock properties, loading conditions, and roadway support parameters. The stress-strain state and strength factor were additionally assessed in Rocscience RS2 for a ventilation roadway driven along the boundary of the goaf. Findings. The width and strength of the coal pillar were found to affect stress redistribution around the gob-side roadway significantly. A limited-width pillar shifted the peak maximum stress 5-10 m deeper into the intact coal mass and reduced its magnitude by approximately 1.6 times compared with the pillarless configuration. Stresses directly above the roadway decreased by a factor of 1.2-1.3. Increasing the pillar strength or its width to 20 m reduced the maximum stresses in the rock mass by almost twofold. The RS2 simulations showed that increasing the mining depth from 450 to 700 m increased the maximum principal stresses by a factor of 1.7-1.9 and the roadway contour displacements by a factor of 1.2-1.35. Originality. Relationships governing stress redistribution and the formation of reduced-stability zones around gob-side development roadways were established as functions of coal pillar parameters, mining depth, and roadway support conditions. Practical implications. The results provide a geomechanical basis for selecting support schemes for gob-side roadways located within zones of elevated rock pressure.

This study summarizes the experience of conducting and maintaining mining operations in unstable zones in mines in Kazakhstan, assessing the mining and geological technical conditions of their operation under difficult mining and geological conditions. A field study and analytical modeling with an assessment of the stability of the boundary mass using the Barton mining method enabled the development of a technology for sinking mining operations with combined fasteners and friction anchors in ore mines.

To achieve the objective with the claimed technical result, a method of fastening mine workings of predominantly rectangular cross-sectional shape with anchor bolts was used, while the applied task of reducing the heaving of soil rocks is to increase the efficiency of mine workings by ensuring that the mine workings. Ensuring the possibility of reliable and of good quality fortified rocks along the contour of making within the boundaries of the zone of possible collapse of rocks. The length of the soil anchors did not significantly affect the condition of the soil rocks. Consequently, that on the deformations and stresses both in the lateral and in the soils are not soil, but lateral anchors. The use of these technological developments will reduce the cost of conducting and maintaining workings by 7–10% with soil anchors (reducing maintenance costs by 7–10%) and will provide an economic effect of 10–15 thousand tenge per running meter of output.

The deflected mode, rock pressure manifestations, conditions of maintenance of mine workings depending on geological and technological parameters have been studied. Researches have allowed establishing the degree of these parameters impact on the effectiveness of anchoring of mine workings. The paper researches such aspects of the problem as rock pressures, terms of maintenance of mine workings, technological parameters and others. The authors consider the expediency of the introduction of anchor certificates which will allow for stability of the rock mining and a reduction of the expenses on realization and maintenance of mine workings.