This article is a summarizing of the results of the author's team on the establishment of technological parameters of underground gasification. It provides a justification of the final chemical and energy products that can be obtained as a result of complex physical and chemical transformations of coal. The thermodynamic processes of formation of the gasification source when changing the composition of the blast furnace mixture and the modes of its application to the georeactor are considered. Moreover, the change in the stress-strain state of rocks depending on the composition of the lateral rocks is taken into account. To better ensure the results are consistent with the well-known principles of thermodynamics and phase formation under the influence of the temperature field and the main chemical reactions occurring in complex gasification processes are presented. The main phase transitions in the georeactor are given for the maximum reception of different energy gases. Particular attention is given to the formation of an appropriate relationship between hydrogen and carbon monoxide, which form a synthesis gas. The Anderson-Schultz-Flory reaction is used to determine the maximum CO concentration in the outlet mixture. In general, the system for determining the material and thermal balance is proposed. These approaches were checked both for working out the coal reserves and for utilization of the mining waste products. Results of this investigation were included to the Roman Dychkovskyi thesis of the scientific degree of the Doctor of the Technique Sciences “Scientific Principles of Technologies Combination for Coal Mining in Weakly Metamorphoses Rockmass”. Also, this results were partially presented on international scientific and practical conferences “Forum of Miners” from different years. They contain the researches, which were conducted within the project GP – 489, financed by Ministry of Education and Science of Ukraine.