Influence of Coal Microstructure on Gas Content of the Face Area
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Influence of Coal Microstructure on Gas Content of the Face Area O. N. Malinnikovaa*, E. V. Ul’yanovaa, A. V. Kharchenkoa, and B. N. Pashicheva a
Academician Melnikov Institute of Comprehensive Exploitation of Mineral Resources–IPKON, Russian Academy of Sciences, Moscow, 111020 Russia *e-mail: [email protected] Received May 18, 2020 Revised May 26, 2020 Accepted May 29, 2020
Abstract—The author study gas content of coal seams in the face areas in mines of SUEK-Kuzbass. It is found that gas content of coal samples from newly exposed face ranges between 2.4 and 13.5 m3/t and makes 32–60% of natural gas content of studied seams. The coal seams with lower gas content in face area have more ordered microstructure estimated by mean of plotting entropy–structure complexity diagrams based on thousandfold enlarged digital images of coal surface. Coal seams with more chaotic structural arrangement possess both higher natural gas content and gas saturation in face area. Keywords: Coal seam, face area, methane, gas content, microstructure, informational entropy. DOI: 10.1134/S106273912003683X
INTRODUCTION
The long-term development program for the coal mining industry sets the requirement to decrease the mortality index in accident rate down to 0.05 person per million ton. Methane explosions due to high gas accumulation in mines, with a high death toll are to be eliminated completely. In the meanwhile, both Russia and other countries in the world lack advanced experience of high-productive mining of coal seams with faulting and high gas content, accompanied by high methane emissions and instantaneous gas pollution in mines. Methane release from coal seams to longwalls is largely governed by natural methane content of coal and by longwalling activities in the face area [1–3]. An important factor of gas release during coal cutting and haulage is gas content of the face zone of coal seam and coal nearby an exposed surface, despite preliminary drainage and natural outgassing, can yet contain much methane [4]. Gas content of the face zone substantially conditions gas content of roadways during drivage and actual mining, and essentially determines ventilation modes, permissible output per face and overall gas balance of longwall during face cutting and haulage of coal along roadways [5, 6]. Kuzbass coal seams have a common feature of higher gas content with depth but differ in the ability to accumulate, retain and liberate methane, dependent on methane–coal bonding, which results in both different natural gas content and different gas content of the face-zone coal [7–11]. Extensive research yet lacks studies into the coal–methane bonding. Inter-connection of coal and methane governs absorption prop
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