Effect of petrographic composition on coal ability to retain methane

During coal mining, much methane remains in face-adjacent rock mass. Using the procedure developed by the IPKON Institute, the residual gas content is determined in face areas of coal seams in Kirov Mine and Ruban Mine of SUEK-Kuzbass. The electron paramagnetic resonance (EPR) spectroscopy of coal shows that the EPR spectra represent the superposition of two signals: from unpaired electrons of conjugate systems and from unpaired electrons in aliphatic components of coal, which form free valences. The number of paramagnetic centers in the aliphatic components of coal is much less in coal samples having low residual gas content and much higher in coal samples having higher residual methane content. This allows suggesting that methane is retained by the paramagnetic centers in the aliphatic components of coal and that the aliphatic components in coal having higher residual gas content should be more loose and less ordered. The microstructural nonuniformity of these coal samples was examined using the entropy–complexity diagrams plotted using the digital coal surface images from the scanning electron microscopy. Coal particles with glossy surface (rich with vitrinite) from seams having higher residual methane content differ from coal particles from seams having lower gas content by more nonuniform microstructure. Duller surface particles of coal samples having dissimilar residual gas content feature no differences in microstructure.

Zakharov V. N., Ulyanova E. V., Malinnikova O. N., Pashichev B. N. Effect of petrographic composition on coal ability to retain methane. MIAB. Mining Inf. Anal. Bull. 2021;(12):88-98. [In Russ]. DOI: 10.25018/0236_1493_2021_12_0_88.

The study was supported by the Russian Foundation for Basic Research, Grant No. 19-05-00824.

V.N. Zakharov¹, Corresponding Member of the Russian Academy of Sciences, Director of IPKON, e-mail: ipkon-dir@ipkonran.ru,
E.V. Ulyanova¹, Dr. Sci. (Eng.), Leading Researcher, e-mail: ekaterina-ulyanova@yandex.ru,
O.N. Malinnikova¹, Dr. Sci. (Eng.), Head of Laboratory, e-mail: olga_malinnikova@mail.ru,
B.N. Pashichev¹, Graduate Student, Leading Engineer, e-mail: borisnik-pa@yandex.ru,
¹ Institute of Problems of Comprehensive Exploitation of Mineral Resources of Russian Academy of Sciences, 111020, Moscow, Russia,

E.V. Ulyanova, e-mail: ekaterina-ulyanova@yandex.ru.

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