National University of Science and Technology ‘MISIS’, Moscow, Russian Federation:

E. L Kossovich, senior researcher, scientific-educational laboratory of physics and chemistry of coals, Candidate of Physico-mathematical Sciences, e.kossovich@misis.ru
S. A. Epshtein, Head of scientific-educational laboratory of physics and chemistry of coals, Doctor of Engineering Sciences
V. L. Shkuratnik, Professor, Doctor of Engineering Sciences

Federal State Autonomous Educational Institution of Higher Education «Ural Federal University named after the first President of Russia B. N. Yeltsin»:
M. G. Minin, Assistant of the Department of Physical Methods and Quality Control Instruments of the Physics and Technology Institute

Modern methods of depth-sensing indentation could be a source of essential information on coals mechanical properties at different scales in order to characterize local properties of individual microcomponents as well as their complexes. Such methods allow characterization of coals structural components response at external loading, their ability or inability to be restored after unloading. Automatically driven grid measurements made at specifi c area of sample allow mapping of elastic moduli and hardness to study inhomogeneity of coals microcomponents and their complexes, etc. A number of methodical problems related to using of depth-sensing indentation for coals mechanical properties characterization are analyzed. These include complications at fulfilment of special requirements for samples preparation and conditions of experiments. The necessity was pointed out for development of new approaches for interpreting of experimental results obtained at different scales. Solution of the methodic problems analyzed in the work will allow deriving of adequate information on coals mechanical properties. Such information is needed for prognosis of coals dust and gas outbursts, coal products quality loss evaluation at transportation and storage, studying of factors influencing concentration and size of coals dust formed at coals mining and processing, etc.
The work was financially supported by the Russian Science Foundation (grant # 16-17-10217).

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