Purpose. The substantiation of accounting the deformation-strength characteristics of the collapsed rocks and the rocks consolidating near the reusable preparatory mine working of the mined-out space to optimize the loading parameters of its fastening and security systems. Improving the research adequacy and recommendations reliability. Methods. By means of computational experiments based on the finite-element method, the influence has been studied of rigidity of the collapsed rocks and consolidating rocks in the mined-out space on the level of intensity of the load-bearing elements of the fastening and security systems of mine working. The analysis has been performed of the stress-strain state of the geomechanical system load-bearing elements, as well as comparative mine research. Findings. The research results and analysis are represented of the stress-strain state of the fastening and security systems elements in the preparatory mine workings with different degree of rigidity of the collapsed and consolidated rocks of the mined-out space. The patterns of the rigidity influence of the collapsed roof rocks on the stable state of preparatory mine workings have been assessed. Originality. A different-valued relation has been established between the deformation-strength characteristics of the collapsed rocks in the mined-out space and the elements of fastening and security systems of mine working, which should be considered when optimizing the modes of their operation. It has been revealed that the increased loading on the combined roof-bolting system elements protects the frame support from the increased rock pressure, which contributes to reducing the section losses of mine working. Practical implications. The research performed is the basis for the parameters optimization when maintaining the preparatory mine workings for their repeated use and also for the rational parameters search of the combined roof-bolting system in order to develop a method for choosing its parameters depending on mining and geological conditions.

Purpose. The investigation of the stress-strain state (SSS) of a parting under the joint and downward mining of coal seams. Methods. The studies have been carried out on the basis of a computational experiment by means of the finite elements method, mining observations of rock pressure manifestations and their comparative analysis. Findings. A research methodology has been developed of the parting rocks state under the joint and downward mining of coal seams. Originality. The patterns of the stress-strain state change of the parting rocks have been determined in the process of joint mining of two coal seams by the descending order. Practical implications. The conducted researches will make possible to improve stability of mine workings and their repeated use.

Purpose. To estimate the probability of interstratal rocks stability loss during simultaneous mining of two seams in series in the descending order. Methods. Methods of a computing experiment and mine observations were used for conducting the research. Findings. Recommendations for the improvement of 914 bolting system parameters of complex roadway for possibility of its reusing are developed. Originality. Regularity of stress-strain state change of parting during simultaneous mining of coal seams with the purpose to reveal the constituent of rock pressure manifestations during the top seam mining is studied. Practical implications. The received results can be generalized for the purpose of providing recommendations concerning bolting and supporting of mine workings during simultaneous mining of seams in series.

Purpose. Investigating conditions of conducting and maintaining excavation works during mining of seam . Evaluating probability of parting rocks stability loss in terms of top-down mining of two contiguous seams in a series. Methods. Carrying out computational experiments by finite elements method for investigation of the stress-strain state of lithological varieties of parting which is overworked and underworked by stoping on seams and . Findings. The paper presents the results of the analysis of the vertical and horizontal stress components distribution zones along all the height of the parting for the rock types compiling it, treating separately the impact produced by stoping on seams and on the formation of the stress-strain state. Originality. The research substantiates the possibility of disturbed rocks sections interlocking and formation of a single zone of softening along the thickness of parting during combined (with a certain displacement in the seam plane) top-down stoping on the series of seams and , which are not referred to as “adjacent seams” according to the normative documents. Practical implications. The paper describes the possibility of the significant interrelation of contiguous seams during their simultaneous top-down stoping even if they are not related to the category of “adjacent seams”. Therefore, in severe mining and geological conditions, it is recommended to estimate the probability of rocks softening along all the height of the parting.

Purpose. Justification of conditions for reusal of extraction mine working by maintaining system parameters of resin-grouted and rope roof bolts. Methods. Wide range of investigation of stress-strain state of coal-bearing massif condition and combined support system of resin-grouted and rope roof bolts was carried out by the method of computing experiment. Findings. The results are related to stress-strain state of coal bearing massif conditions around reused extraction mine working during roof reinforcement by combined anchoring system consisting of resin-grouted and rope roof bolts. Originality. The new task solution by the method of computational experiment is shown in the paper. Curves characterizing the stress-strain state of the system “rock massif – combined anchored reinforcement” are received. The investigations carried out are the basis for support system selection, adapted to the character of rock pressure manifestation. Practical implications. Analytical investigations are the basis for selecting optimal support system aimed at its loading and improving exploitation characteristics that are essential part of increasing the rock massif stability.