Determination of Sulfur Content in Mineral Mass for Prediction of Hazardous Properties of Coal Mine Seams

Abstract

Introduction. Sulfur is found in the organic and mineral parts of all types of solid fuels, and its concentration determines the extent of the hazardous characteristics of mine seams. Therefore, research on the determination of sulfur content in fossil fuels has not lost its relevance. The total sulfur content and its varieties has been studied in most cases in terms of the efficiency of fuel processing processes, the quality and environmental safety of coal products. Less attention was paid to the hazardous properties of mine seams, forecasting and developing preventive measures for endogenous fires in coal mines. This work aims to develop an engineering method to calculate the elemental sulfur content in the mineral mass of coal to predict the hazardous properties of mine seams.Materials and Methods. According to the results of the correlation analysis, we established how the sulfur content in the combustible part of the fuel depended on the total sulfur. We analyzed data on coals from almost all mine seams of the Donetsk and Lviv-Volyn coal basins. We presented the ash ratios for the formation and basin samples, as well as the information about the total sulfur and sulfur content in the combustible part. This allowed us to estimate the sulfur content in mineral impurities by calculation. The initial data for developing the method were taken from reference and regulatory documents.Results. Seven sets were considered, which included from 149 to 1827 mine seams. For each, reference and calculation data were summarized:- sulfur content — total (Std) and in the combustible part of the fuel (Sг);- conditional points for adjusting the indicators to avoid obtaining negative average values;- empirical equations that describe the calculated and corrected dependencies based on the ratio of Std and Sг;- correlation of these indicators;- ranges of change in ash yield.All this information was presented for clean and raw coals, for ash yields of more and less than 10%. In one case, satisfactory results were noted for determining the calculated sulfur content in a conditionally non-combustible mass. This was a set of 149 mine layers. For 13 of them, the difference in indicators (Std – Sг) was greater than or equal to zero. For 136 — less than zero. For 81, the sulfur content in the conditionally non-combustible part of the fuel Sн was less than zero. At the same time, there was a sufficient level of correlation (0.79) and a limited range of changes in ash yield (2.4–10). The empirical equation corresponding to this set was recommended for predicting the hazardous properties of mine seams with an ash yield of less than 10%.Discussion and Conclusion. The results of this study can be used to improve regulations for the safe conduct of mining activities, taking into account sulfur content in organic matter and in mineral impurities of fossil coal.