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ArticleName Analysis of the connection between the microstructure and gas-dynamic fracture susceptibility in coal
DOI 10.17580/gzh.2017.11.04
ArticleAuthor Bobin V. A., Malinnikova O. N., Odintsev V. N., Trofimov V. A.

Academician Melnikov Institute of Integrated Mineral Development – IPKON, Russian Academy of Sciences, Moscow, Russia:

V. A. Bobin, Head of Department, Doctor of Engineering Sciences
O. N. Malinnikova, Head of Laboratory, Doctor of Engineering Sciences
V. N. Odintsev, Leading Researcher, Doctor of Engineering Sciences,
V. A. Trofimov, Leading Researcher, Doctor of Engineering Sciences


The concept of the governing role of coal microstructure in the mechanism of fast transition of methane between the bound and unbound states and on participation of methane in gas-dynamic fracture of coal, starting from micro-scale, is developed. The concept contains two determinative factors – transition of methane molecules between bound and unbound state and ability of free methane to disintegrate coal in micro-fractures. The studies used the methods of fractal analysis of multi-scale images of damage obtained in outburst-hazardous and outburst-nonhazardous coal using a scanning electron microscope with the resolving power around 100 nm; analytical estimation of time of bound methane molecule liberation from coal particles by the mechanism of diffusion; assessment of stress state of coal particles after contact interaction between them and the theory of tensile micro-fracturing due to release of methane molecules in the fracture space. It follows from the joint analysis of methane desorption and coal fracture conditions that the governing role of coal micro-structure is conditioned by the possibility to determine participation of bound methane in the dynamic fracture of coal at a micro-level. Moreover, by contrast to unbound methane initially occurring in coal, disintegration of coal by bound methane should unavoidably transfer to larger scales. Peculiarities of bound methane conditions in coal (occluded or dissolved methane) are of no high importance for gasdynamic fracture of coal. The undertaken research supports the conclusion that the analysis of coal damage at a micro-scale can be an efficient method to predict coal and gas outbursts in coal beds.

keywords Coal microstructure, bound methane, coal bed, coal fracture, fractal analysis, fracture, gas release

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