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Research methods for the electrophysical and structural characteristics of fossil
coal T.A. Vasilenko1, A.K. Kirillov1*, V.V. Sobolev2, A.S. Doroshkevich3, N.V.
Doroshkevich4 1Institute for
Physics of the Mining Processes of National Academy of Sciences of Ukraine,
Dnipro, Ukraine 2Dnipro
University of Technology, Dnipro,
Ukraine 3Donetsk
Institute for Physics and Engineering
named after A.A. Galkin of the
National Academy of Sciences of Ukraine, Kyev,
Ukraine 4Vasyl’ Stus Donetsk National University, Vinnytsia,
Ukraine * Corresponding author: e-mail: kirillov1953@ukr.net Physical and technical problems of mining
production, 2019, (21), 6-31. https://doi.org/10.37101/ftpgp21.01.001 ABSTRACT(IN UKRAINIAN) ABSTRACT Purpose of the
research is justification of the criteria and
parameters of the forecast of outburst hazard in a coal seam with using
non-invasive methods of testing in the course of deep mining. The results of
testing of coals by the methods of impedance spectroscopy, small-angle
neutron scattering, Raman spectroscopy and
low-temperature nitrogen adsorption are considered that are successfully
applied to the study of transport and structure characteristics of coals of
varied degree of coalification at Institute for the Physics of Mining
Processes. First of all, an attention is paid to impedance spectroscopy that
allowed fixation of specific features of diffusion and electric conductivity
in coals of early stages of metamorphism in a wide frequency range from 500
Hz to 1,5 МHz. A complex
hierarchical structure of coal substance is a component determining the
conditions of formation of accident situations in coal
mines. Physical methods of testing listed above are
now successfully applied to the study of structural features and the
tendency of coal to sudden methane outbursts. Findings. Electrophysical characteristics of coal samples differ
substantially. The transport properties of the coal of longflame-gas
rank are the most essentially modified when passing from a “calm” zone of the
coal seam to the zone of geological disturbance that occurs by the mechanism
of brittle deformation according to Raman spectroscopy. By the data of
impedance spectroscopy, the structural organization of a coal sample taken in
the zone of tectonic disturbance differs from the hierarchical one and can be interpreted as a mass fractal. Originality. The susceptibility of the applied methods to variations of the physical
properties of coal in geological disturbances is analyzed. The most susceptible method is Raman
spectroscopy when speaking about the analysis of tectonic disturbances and
fixation of the characteristics of the type of
deformation (brittle or ductile) in the
disturbance. Impedance spectroscopy allows making conclusions about the
transport properties of fluids in the pore space of coal in calm and
disturbed zones of a coal seam by the measured electric conductivity in a
wide frequency range. Practical implications. The results of
the research demonstrate a possibility of diagnostics of the transport
properties of coals by the data about their electrophysical
properries and possible application of non-invasive
methods of analysis to the forecast of outburst-prone zones of coal seams in
the course of deep mining of fossil coal. Keywords: impedance spectroscopy, neutron scattering,
electrical conductivity, fossil coal, tectonic disturbance, low-temperature
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