LASER-ULTRASONIC SPECTROSCOPY OF THE PECHORA BASIN COAL MICROSTRUCTURE

Samples of the Pechora basin coal are tested with the pre-determined uniaxial compression strength in the normal direction to bedding. The test data show that different samples have close values of the uniaxial compression strength. The laser–ultrasonic spectroscopy in the mode of automatic scanning of coal sample surface at a pitch of 1 mm visualizes the internal structure of coal. It is found that in the vertical sections of the samples, cracks are mostly horizontal in conformity with the direction of bedding. The geometrical dimension and depth of cracks are determined. Based on the precision measurements of Pand S-wave velocities, the local values of Young’s modulus and Poisson’s ratio are for the first time obtained for coal accurate to 1 and 5%, respectively. The presence of cracks from 0.5 to 3 mm long with an opening of 80–200 μm results in dispersion of Young’s modulus and Poisson’s ratio in the ranges from 6.81 to 7.25 GPa and from 0.23 to 0.29. By the calculated values, the map of Young’s modulus distribution over sample surface is plotted.


Acknowledgements: This study was supported by the Russian Foundation for Basic Research, Project No. 19-05-00824.


For citation: Kravtsov A., Ivanov P. N., Malinnikova O. N., Cherepetskaya Е. B., Gapeev A. A. Laser–ultrasonic spectroscopy of the Pechora basin coal microstructure. MIAB. Mining Inf. Anal. Bull. 2019;(6):56-65. [In Russ]. DOI: 10.25018/0236-1493-2019-06-0-56-65.

Keywords

Laser–ultrasonic structurescopy, X-ray tomography, coal, geodynamic phenomena, methane, local elasticity moduli.

Issue number: 6
Year: 2019
ISBN: 0236-1493
UDK: 622.33+620.179.16
DOI: 10.25018/0236-1493-2019-06-0-56-65
Authors: Kravtsov A., Ivanov P. N., Malinnikova O. N., etc.

About authors: A. Kravtsov, PhD, e-mail: kravtale@fsv.cvut.cz, Department of Construction Technology, Faculty of Civil Engineering in Prague, Thákurova 7/2077, 166 29 Prague 6 — Dejvice, Czech Republic, P.N. Ivanov (1), Engineer, e-mail: pavelnivanov@mail.ru, O.N. Malinnikova, Dr. Sci. (Eng.), e-mail: olga_malinnikova@mail.ru, Institute of Problems of Comprehensive Exploitation of Mineral Resources of Russian Academy of Sciences, 111020, Moscow, Russia, Е.B. Cherepetskaya (1), Dr. Sci. (Eng.), Chief Researcher, e-mail: echerepetskaya@mail.ru, A.A. Gapeev (1) — Student, e-mail: tema.gapeev135@yandex.ru, 1) Mining Institute, National University of Science and Technology «MISiS», 119049, Moscow, Russia. Corresponding author: P.N. Ivanov, e-mail: pavelnivanov@mail.ru.

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