Structure and shape analysis of medium-rank coal dust particles

The increase in coal production against the background of complication of geological conditions in coal mining, with multiplication of various hazards as a result necessitates more comprehensive microscopic research of the structure, shape and properties of coal and coal dust on the level of intermolecular interactions toward development of the explosion and fire safety measures in coal mines. Almost all coal seams being mined are hazardous in terms of coal dust explosibility. For the research, coal dust was sampled in seam E-5 (fat coal) at four points: at a belt-to-belt reloading point 200 m away from longwall; on a mobile conveyor; at a belt-to-belt reloading point 3200 m away from longwall; coal from longwall behind a shearer. The structure and properties of coal dust particles were analyzed on a high-resolution scanning electron microscope: JEOL, JSM-6380LA. The samples were treated with a palladium-and-gold mixture under high pressure in a vacuum. It is found that the amount of sheet-like particles is higher than the amount of isometric particles: the former is 55.4% on average. The particles with an aerodynamic diameter of 5–10 µm have much more satellites 2 to 0.5 µm in size. At small values of radii of particles (of the order of 1 µm), the forces of intermolecular attraction exceed the forces of gravity by 22 500 000 times. There exist counter-autohesion forces which govern aggregative stability of dispersive structures, and the value of this counter-action is 1.7077·10–7 N for a particle with a radius of 17 µm. The research findings allow determining oxidation behaviors and enable developing measures towards reduction in explosion risk of coal dust.

Skopintseva O. V., Rybichev A. A., Balovtsev S. V. Structure and shape analysis of medium-rank coal dust particles. MIAB. Mining Inf. Anal. Bull. 2025;(2):5-15. [In Russ]. DOI: 10.25018/0236_1493_2025_2_0_5.

O.V. Skopintseva¹, Dr. Sci. (Eng.), Professor, e-mail: skopintseva54@mail.ru, ORCID ID: 0000-0002-7257-8720,
A.A. Rybichev¹, Graduate Student, Assistant, e-mail: rybichev@yandex.ru, ORCID ID: 0009-0005-9269-201X,
S.V. Balovtsev¹, Cand. Sci. (Eng.), Assistant Professor, e-mail: balovcev@yandex.ru, ORCID ID: 0000-0002-0961-6050,
¹ University of Science and Technology MISIS, 119049, Moscow, Russia.

A.A. Rybichev, e-mail: rybichev@yandex.ru.

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