On using cyclic nanoindentation technique to assess coals propensity to fine dust formation

Coals propensity to dust release during mining and transportation is an urgent topic of research due to the fact that coal dust is one of the main reasons for various accidents and environmental impacts. Recent studies revealed new information on connections between coal brittleness and their mechanical properties at low-dimensional scales. It has been shown that nanoindentation at coals leads to their crushing under the indenter tip. But the traditional nanoindentation technique cannot be considered as a universal approach for characterization of coals proneness to fine dust formation under mechanical and other (e.g. oxidation) impacts. This paper presents an approach for assessing changes in the mechanical properties of coals and their tendency to crushing with fine dust formation based on experiments on cyclic nanoindentation. The methodology includes samples preparation technique, approaches for the selection of areas for experiments, conditions for conducting the experiments and processing the results, as well as their interpretation. The experiments revealed the dissimilarities in the tendency to crushing of samples of two anthracites from different deposits of the Russian Federation and a natural graphite. This was revealed by characterization of changes in their stiffness and the fracturing ability with increasing of maximal load during cyclic loading. The differences in the samples proneness to fine dust (particles) formation under the mechanical impacts at low scales could be connected with the known data on alteration in their structure in the row: relatively lowand high-metamorphosed anthracites and natural graphite.

Kossovich E. L., Epshtein S. A., Golubeva M. D., Krasilova V.A. On using cyclic nanoindentation technique to assess coals propensity to fine dust formation. MIAB. Mining Inf. Anal. Bull. 2021;(5):112-121. [In Russ]. DOI: 10.25018/0236_1493_2021_5_0_112.

The work was supported by the Russian Science Foundation, grant No 18-77-10052.

E.L. Kossovich¹, Cand. Sci. (Phys. Mathem.), Senior Researcher, e-mail: e.kossovich@misis.ru,
S.A. Epshtein¹, Dr. Sci. (Eng.), Senior Researcher, Head of Laboratory, e-mail: apshtein@yandex.ru,
M.D. Golubeva¹, Laboratory Assistant,
V.A. Krasilova¹, Graduate Student, Engineer,
¹ Scientific and Educational Testing Laboratory «Physics and Chemistry of Coals», National University of Science and Technology «MISiS», 119049, Moscow, Russia.

E.L. Kossovich, e-mail: e.kossovich@misis.ru.

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