Institute of Coal, Federal Research Center of Coal and Coal Chemistry, Siberian Branch, Russian Academy of Sciences, Kemerovo, Russia:

Yu. F. Patrakov, Professor, Doctor of Chemical Sciences, yupat@icc.kemsc.ru
S. A. Semenova, Associate Professor, Candidate of Chemical Sciences

The introduction of high-performance mining equipment in coal mines increases formation of the most explosive and fire-hazardous high-dispersed coal dust fractions. Degradation of large coal particles to nano- and micro-sizes during mining occurs mainly as a result of percussion, compression (crushing) and attrition of monoliths. The study into the mechanisms of formation of the most hazardous fine dust is an urgent task of the coal industry. This article describes the results of the study into the fractional composition of coal dust particles obtained in laboratory by modeling the main types of physical effects in mine—percussion, compression and attrition. The test objects were coal samples of low and middle rank and various petrographic composition from different Kuzbass deposits. The study of the particle size distribution in coal dust was carried out using a laser diffraction microanalyzer meant for the automatic granulometric rapid analysis. The parameters of the dust particle size distribution were the average particle size, size distribution of dust particles, density of distribution, arithmetic mean diameter and the modal magnitude values. The studies have determined the features of the influence exerted by each type of destruction (compression, percussion, attrition) on the nature of the particle size distribution of coal dust. It is shown that for the studied coals of ranks I–III, the petrographic composition has the most significant effect on the change in the particle size distribution of dust. Bright and semi-bright coals exhibit general properties of the particle size distribution under various types of destruction. Percentage of fine dust grows under percussion, while coarse dust particles increase in attrition. Semi-dull coals, in contrast to the bright, are more resistant to degradation by percussion, while attrition generates greater number of fire- and explosion-hazardous fine dust. Under compression, the particle size distribution of dust, regardless of the petrographic composition, is relatively uniform.
The authors express their deep gratitude to S. A. Sozinov, Candidate of Physical and Mathematical Sciences, Director of the Common Use Center at the Federal Research Center of Coal and Coal Chemistry.

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