Purpose. The research purpose is to develop a concept for complex mining of mineral resources from coal mines using the example of PJSC DTEK Pavlohradvuhillia mines with a transition to multi-product production of clean drinking water, utilization of methane, secondary coal from rock dumps and sludge reservoirs, low-potential thermal energy of mine groundwaters and associated raw materials from desalination waste. Methods. The research uses an integrated approach, which includes an analysis of existing experience and available complex coal mining technologies, laboratory studies of mine water desalination technology by the reverse osmosis method with thermal distillation of concentrated brine, and chemical analysis using ElvaX laboratory equipment. Findings. This paper presents the research results of a comprehensive analysis of mineral raw material resources related to coal mining. The technically achievable energy potential that can be produced from the secondary coal of rock dumps and sludge reservoirs has been determined, which in total is 183.3 TJ. The annual heat potential of methane gas utilization has been estimated, which in total of PJSC DTEK Pavlohradvuhillia’s mines reaches 7.1 PJ. The possibility of extracting up to 1.12 TJ/year of associated thermal energy from the water-drainage installation of mine complexes has been determined. For the conditions of the Zakhidno-Donbaska mine, the authors of the paper have developed a technological scheme for the water preparation process by the reverse osmosis with the desalination brine treatment by the method of multistage evaporation on adiabatic evaporators. Originality. For the first time, the energy flows related to coal mining technology have been comprehensively analyzed for the possibility of their joint use to cover the needs of the mine complex. The prospects for complex mining of mineral resources have been assessed based on the adaptation of the mine complex production facilities to the multi-product production of clean drinking water, utilization of methane gas, low-potential thermal energy from mine groundwaters and secondary raw materials of desalination waste. Practical implications. The proposed set of technological solutions will ensure the sustainable development and diversification of the production of PJSC DTEK Pavlohradvuhillia coal-mining enterprises, as well as the effective transformation of coal-mining cities during the period of transition from mono-product production to the creation of multi-business production complexes that comply with ESG principles. The creation of multi-product mine complexes capable of producing not only coal, but also heat and associated mineral raw material resources, should become a guarantee of stable social-economic development of coal-mining regions.

Purpose.The research aims to substantiate the general provisions on coordination of the experimental-analytical research results of the influence of pre-drilled wells on the intensity of gas-dynamic phenomena manifestations (using the example of the mining-geological conditions of the phenomena at the PJSC Mine Administration Pokrovske, Ukraine). Methods. The research uses an integrated methodology consisting of indirect experimental methods for studying the adjacent rock mass state and tendencies. Findings. It has been proven that indirect experimental indicators of the rock mass state around the tunneling face are related to the peculiarities of the distribution of its stress-strain state components. Based on this research, the well lengths of up to 10-15 m has been determined to effectively and safely de-stress the rock mass. The experimental research validity is confirmed by conducted computational experiments, in the course of which the dependence of the propagation parameters of the stress-strain state component concentrations on the degree of hardness of the lithotypes is revealed, and a geomechanical substantiation to the tendencies of propagation of rock pressure anomalies near stoping and tunneling faces is given. The new knowledge obtained is the basis for creating a method for calculating rational parameters for the location of de-stressing pre-drilled wells. Originality. An objective assessment of the degree of adequacy and reliability of the computational experiment results has been made under the condition of using a new geomechanical model with mine studies of seismic-acoustic signal parameters and the initial gas release velocity. The main tendencies of vertical σу, horizontal σх and σz, as well as stress intensity propagation have been identified. The obtained results of exploring the bottom-hole mass are aimed at substantiating the parameters of anti-outburst measures for all preparatory mine workings. Practical implications. The conducted research is implemented in creation of a calculation method and recommendations for the selection of rational parameters for the location of de-stressing pre-drilled wells for the purpose of weakening the rock mass, surrounding the tunneling face, and reducing the probability of gas-dynamic phenomena occurrence due to the controlled weakening of adjacent rocks.

Purpose. The purpose is to develop the calculation methods for minimizing the load on the fastening system of the preparatory mine working in difficult mining and geological conditions of its maintenance. Methods. By analysing the multivariate computational experiments on the study of the stress-strain state of the load-bearing elements of the ‘massif – support’ system in the preparatory mine workings by means of the finite-element method, as well as mine observations and measurements of displacement in the coal-overlaying rock formation. Findings. An algorithm has been developed for searching the rational modes of the fastening system resistance and methods for minimizing the load on the support of the preparatory mine working, maintained in very complex mining and geological conditions. Originality.The methodical principles have been developed of minimizing the load on the fastening system of the preparatory mine working, which are based on the use of a combination of stress-strain state studies of the ‘massif – support’ system by means of the finite element method and provisions of normative documents for calculating the dimensions of the dome of natural equilibrium of the mine working roof rocks. Practical implications. The operation modes optimisation of the load-bearing elements interaction of the mine working fastening system reduces the material and labour costs during its construction and increases its stability during operation. Keywords: analysis, calculation, optimization, support, preparatory mine working, stope works, roof rocks, collapse

The aim of the forecasting effort is to identify troublesome zones of stability loss by a parting lengthwise of the extraction panel under the joint and downward mining of coal seams. Analyses have been carried out of active stress component curves for a 3-D model computational experiment compared with the strength characteristic of each lithotype of a parting. An algorithm has been developed for the stability assessment of a parting lengthwise along the extraction panel. The relationship patterns have been estimated between the sizes of the parting rocks discontinuity zones and the main geomechanical parameters. A scientifically grounded basis has been created for the detection of the parting rock weak zones lengthwise along the extraction panel for the calculation of the mounting and security systems of the development works. A complex of underground instrumental observations was made, which was used to set up a correspondence of patterns to indicate the variation in rock pressure manifestation intensity and the tendencies for changes in the parting structure. All of this confirms the adequacy of the techniques for parting state forecasting, which is recommended for use in the engineering documentation for the joint and downward mining of coal seams.

The new support patterns have been revealed for controlling the combinations of the roof rocks strengthening processes in extraction mine workings with combined roof-bolting systems. It has been established that in adjacent roof rocks, by means of a combination of rope bolts and resin-grouted roof bolts, an armored and rock plate is formed, the high load-bearing capacity of which is achieved by maintaining the horizontal thrust forces that reduces the concentrations of all the stresses components to a level many times lower than the strength characteristics of the lithotypes. The criterion has been substantiated for assessing the resistance level of roof-bolts as a part of the combined roof-bolting system, which is used for determination of the most important geomechanical factors in terms of the system loading degree. The patterns have been established of a degree of loading the roof-bolts being a part of the combined roof-bolting system from the main influencing geomechanical factors. The calculated expressions have been obtained to determine the needed parameters for effectively strengthening the roof in workings by a combined roof-bolting system. The mine experiment analysis has been performed as well.