Purpose. Underground coal gasification, as a complex and technically difficult process, should be supported in many aspects by computer simulations or analytical calculations of rock mass behavior. However, little is known about the formation of stratification cavities in the roof rocks during coal seam gasification. To research the formation of stratification cavities and rocks deformations by mine pressure with the methods of calculation based on hypotheses or statistical information, a number of hypotheses are used. The main purpose is to examine the rock mass behavior and formation of stratification cavities during gasification of a thick coal seam.Methods. Analytical calculations were used as the research method for the work presented. The mathematical model of the stress-strain state of rock mass based on the theory of elasticity, resiliency, and maximum equilibrium, was developed and used in this paper.Findings. Critical analysis of geomechanical models of coal gasification together with their mathematical formulation was the result of considerations presented in this paper. Equations were derived for substantiating parameters of stratification cavities above the goaf of the underground gasifier. Subsequently, the volumes of stratification cavities depending on the length of gasification channel were calculated. The results have significant influence on gasifiers development and the final efficiency of gasification process.Originality. The research results were obtained from analytical calculations of rock mass behavior during thick coal seams gasification. The authors implemented a mathematical model based on the method suggested by professor A. Savostianov which was used in carrying out the calculations. Practical implications.The present study provides a starting point for further research and analytical calculations of rock mass behavior. The data and conclusions outlined in this paper may be useful in preliminary optimization and analysis of coal seams gasification. They can also be a point of reference for more advanced geomechanical simulations.

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The paper represents analysis, which have helped to determine tendencies of usage secondary and renewable resources by means of their utilization within the closed ecological complex while implementing integrated cogeneration systems belonging to various sources. Both the current state and prospects of secondary and renewable resources use within the closed complex of a mining enterprise have been considered. Relying upon philosophical approaches as for the formation of a viewpoint concerning responsibility of the modern society to future generations, tendencies to form energy production and energy consumption on the basis of alternative radical technologies have been proposed. The authors have put forward tendencies to change coal mining and coal use while generating the raw material from the abandoned and out-of-balance reserves. Chances to use cogeneration systems by various energy sources have been considered. Formation of the unified power and chemical system to improve economic and ecologic expediency of the proposed measures is the key tendency of energy perfection as well as minimization of impact on the underground mine environment and on the surface to prolong activities of dying mining territories and to reduce social tension.

Purpose. Setting up and implementation of complex, combined and non-waste power-chemical plant based on underground coal gasification with regard to analysis of its technical and economic efficiency. Methods.Research into the reliability of the gasifier plant components was performed by determining the sequence of processes and operations during underground coal gasification technology at all levels of the process.Findings. It was established that high reliability of coal gasification is ensured by stability of all constituents of the technological elements of the process. The basic steps of combining power and chemical plant specializing in synthetic hydrocarbons production are described. During gasifier plant operation, upgrading of equipment at the general level of mechanization between 0.5 -0.7 will not lead to a serious increase in productivity. Therefore, it is necessary to allocate means and efforts to completion of mechanization of all production processes.Originality. The efficiency of mechanization and automation of processes at a gasifier plant is expressed through the formula of automatic control. We have identified dependencies describing changes in the mechanization efficiency of all technological units of the gasifier plant and productivity growth due to reducing the number of manufacturing operations.Practical implications. Analytical research testifies that effective functioning of the gasifier plant is ensured by automation of all technological processes. Computer system conversion requires additional investments which exceed the costs of mechanization by 1.25 -1.4 times.

The paper represents the analysis, which has helped to establish the usage of gas hydrate technologies in the methane conversion. This gas could be obtained in different ways. Possibilities and sources for the gas obtaining have been demonstrated. Use of other environmentally friendly sources to support operation in such systems in terms of joint energy complex has been considered. The necessary kinetic connections to provide operational sustainability of all the constituents have been given. The approach helps evaluate quantitatively the priority of its physicochemical transformations to obtain gas hydrates artificially. It is possible to transport methane at considerable distances when it is solidified. Actually, in this case there is no necessity to build costly compressor stations and pipelines for its transportation to consumers. The approach is extremely important for mining regions as it helps prolong the operating period and working out of the abandoned and off-balance coal reserves. In this case, it is proposed to apply special gasification technologies tending to maximum methane recovery. The proposed solutions give the possibility to define the trends of our further research. They will be highlighted in the following authors’ studies.