Engineering method for determining the sulfur of mineral impurities for the prediction of hazardous properties of coal seams

Purpose: develop an engineering method for determining sulfur in mineral impurities to predict the hazardous properties of mine seams in mining operations. Methodology: The research methodology and the development of the method are based on a close correlation dependence of the sulfur content in the combustible part of the fuel on the total sulfur for coals of almost all mine seams of the Donetsk and Lvov-Volyn basins. The ratios between the organic mass and mineral impurities are characterized by the yield of ash. The ratio of ash content of reservoir and enriched samples, as well as information about the content of total sulfur and sulfur in the combustible part, make it possible to estimate the sulfur content in mineral impurities by calculation. All the initial data necessary for the development of the method were established experimentally by standard methods over several decades and are given in the reference and regulatory documents on the consumer qualities of coals. Results: The percentage of total sulfur for the entire set of considered coal seams can either exceed the sulfur content in the combustible part of the fuel or vice versa. The difference between the content of total sulfur and its presence in the combustible part of the fuel is, in the first approximation, a criterion for assessing the possible sulfur content in the conditionally non-combustible part of the fuel. Negative values of the criterion indicate the predominant sulfur content in the combustible part, and positive values, in the conditionally non-combustible (mineral) impurities. Based on the available initial experimental data on the content of total sulfur in the combustible part of the fuel, the yield of ash from reservoir and enriched samples, dependencies are proposed for calculating the sulfur content in conditionally non-combustible components. Between the calculated values of the sulfur content in the conditionally non-combustible part and the proposed criterion, correlations are considered for seven sets of coal seams. The formation of the populations was done taking into account the possible influence of enrichment processes and positive or negative values of the proposed criterion. Based on the analysis of empirical dependences of the considered sets of coal seams, the necessary conditions were established for obtaining the most reliable results of the calculated determination of sulfur in conditionally non-combustible (mineral) impurities of fossil coals. Scientific novelty: For the first time, empirical dependences of the sulfur content in conditionally non-combustible (mineral) impurities were established according to the proposed criterion. Practical value: The results are necessary to improve the regulatory framework for the safety of mining operations in terms of predicting the manifestation of hazardous properties of coal seams due to the presence of sulfur varieties.