About the connection of the total porosity of fossil coal with metamorphic transformations of coal seams

Studying the porosity of minerals, in particular coal, and understanding the relationship between its structure and characteristics and properties is necessary for rationalising the use of coal, optimising processing processes, and finding new methods of combating sudden emissions or gas release. The goal was to establish the level of correspondence between the calculated values ​​of the total porosity of coal (according to the empirical equation) and their experimental determination by standard methods, as well as to determine the indicators of the closeness of the correlation dependence of the total porosity on the degree of metamorphic transformations. The research methodology was based on the analysis of the comparison of the compliance of the calculated values ​​of the total porosity for each separate coal seam according to the empirical equation with their values ​​established by standard methods. The results indicated that the physical characteristics of coal, in particular density and porosity, change with the increase in the degree of metamorphism. The porosity of coal, the structure of its porous system and the specific surface determine the filtration, diffusion and sorption processes both in natural conditions of occurrence and during their changes under the influence of various physical and chemical factors. It has been proved that there is a practical absence of correlation between the total porosity of fossil coal and metamorphic transformations of coal seams when assessing the impact of these processes, taking into account the volatile substances yield. The total porosity is a unique characteristic of a particular coal seam within a mine field and is only partially determined by the volatile content. The averaged empirical dependencies on the volatile matter yield provide only a general idea of the trends in coal porosity during metamorphic transformations of coal seams. The results of the experiments make it possible to develop proposals for improving the regulatory framework for predicting the manifestation of dangerous properties of coal seams during mining operations. The facts revealed in the research can be used in regulatory documents to predict the dangerous properties of coal seams, as they allow the development of proposals and methods for improving the regulatory framework for safe mining operations. This will lead to a decrease in the level of accidents with serious consequences, industrial injuries at coal mining enterprises