Moisture as an indicator of the manifestation of hazardous properties of coal seams

Abstract

Purpose: establish the change in the ratios between individual types of moisture and indicators of metamorphic transformations of coal seams after recalculating their values for the working state of the fuel. This will make it possible to predict the manifestation of hazardous properties mining. Methodology: provides for the involvement of the initial experimental data that have been accumulated in normative and reference documents. Results: When conducting research, the experience of using moisture as an indicator for solving three problems at once was taken into account: the criterion for evaluating the metamorphic transformations of coal seams; determination of fuel quality; forecast of the manifestation of hazardous properties of coal seams during mining operations. Different types of moisture at different stages of metamorphic transformations of coal seams are not equivalent in terms of the strength of the bond between water and coal. In some regulatory documents, in some cases, indicators of different types of moisture are used to characterize the moisture content of coal seams, which introduces additional errors in the reliability of the prediction of hazardous properties. In the early and middle stages of metamorphic transformations of coal seams, moisture is not formed for the most part, but only free moisture is mechanically removed from the system. Hard coals and anthracites have different molecular structure, which determines different ratios between the content of free and bound moisture. The content of total moisture is a metamorphic indicator only for organic (combustible) mass, and it is not a reliable criterion for assessing the transformation of coal seams in general. Mandatory pre-moistening of coal in the array in all cases during mining operations is not sufficiently substantiated for different stages of metamorphic transformations of coal seams due to the different ratio between the forms of moisture and the irreversibility of metamorphism processes. Scientific novelty: for the first time, a quantitative assessment of the content of hydrated moisture in mineral impurities and moisture in the organic mass from the degree of metamorphic transformations of coal seams was made. Practical value: the research results make it possible to develop proposals for improving the regulatory framework in terms of predicting the manifestation of hazardous properties of coal seams during mining operations, depending on the presence of different forms of moisture in coals.