The Analysis of Filtration Process in the Coal Seam Excavated with Long Pillars along the Strike


The underground coal field mining is inevitably associated with coal oxidation process accompanied with the thermal energy emission and the formation of coal self-heating spots. The self-heating spots can emerge in both coal dust accumulations deposited in the excavations and in the excavated coal seams. 

It is known that self-heating is caused by both chemical processes accompanied with heat emission and physical processes, primarily the filtration of gas-air mixtures through porous and fractured layers of rocks and coal seams. Although the filtration processes accompanying oil and gas field exploration have been thoroughly studied, similar processes accompanying coal mining have been studied less.

The article focuses on the mathematic problem concerning the filtration process in the coal seam when excavated by long pillars. In this system, both fresh airflows and worked out flows move in opposite directions and under different pressures along the mine roadway and the ventilation opening. This causes so-called air suctions due to air infiltration through the coal seam. In theory, this problem has not been solved yet and thus is considered urgent. Based on the classic filtration theories and assumptions regarding the coal seam isotropy and homogeneity, the one-dimensional initial value problem describing the non-stationary air filtration process through the coal seam was formulated. The solution provided explicit formulas to determine the pressure and rate of air-gas mixture filtration and identified several regularities of the filtration process in the coal seam. Particularly, it was established that the filtration rate increases significantly in the direction towards the ventilation opening, especially at the initial stages of filtration. In process of time, however, the filtration rate aligns and after 5 days, the rate difference is not so significant. 

1. Shlapakov P.A., Erastov A.Yu., Khaymin S.A., Lebedev K.S., Kolykhalov V.V., Shlapakov E.A. Endogenous fire safety in kuzbass coal enterprises. Vestnik Nauchnogo tsentra VostNII po promyshlennoy i ekologicheskoy bezopasnosti = Bulletin of Scientific Centre VostNII for Industrial and Environmental Safety. 2019. № 1. pp. 14–21. (In Russ.). DOI: 10.25558/VOSTNII.2019.69.88.002
2. Un L.K., Cherdantsev S.V., Popov V.B., Shlapakov P.A., Erastov A.Yu. Electrical Prospecting to Detect Places of Spontaneous Heating in Olzherasskaya-Novaya Coal Mine: Case Stady. Journal of Mining Science. 2017. Vol. 53. pp. 191–196. 
3. Khristianovich S.A. On the filtration theory premises. Fiziko-tekhnicheskie problemy razrabotki poleznykh iskopaemykh = Physical and technical issues of mineral excavation. 1991. № 1. pp. 3–18. (In Russ.).
4. Charnyy I.A. Underground gas dynamics. Moscow: Gosudarstvennoe nauchno-tekhnicheskoe izdatelstvo neftyanoy i gorno-toplivnoy literatury, 1963. 397 p. (In Russ.).
5. Barenblatt G.I., Entov V.M., Ryzhik V.M. Movement of gases and fluids in natural deposits. Moscow: Nedra, 1984. 211 p. (In Russ.).
6. Amirat Y., Shelukhin V.V. Homogenization of Harmonic Maxwell Equations with Allowance for Interfacial Surface Currents: Layered Structure. Journal of Applied Mechanics and Technical Physics. 2019. Vol. 60. pp. 593–607.
7. Shelukhin V.V., Kontorovich A.E. Behavior of Viscoplastic Rocks near Fractures: Mathematical Modeling. Doklady Physics. 2019. Vol. 64. № 12. pp. 461–465. DOI: 10.1134/S1028335819120036
8. Shelukhin V.V., Neverov V.V. Dense Suspension Flows: a Mathematical Model Consistent With Thermodynamics. Journal of Fluids Engineering, Transactions of the ASME. 2022. Vol. 144. № 2. DOI: І10.1115/1.4051857
9. Zakharov V.N., Malinnikova O.N., Trofimov V.A., Filippov Y.A. Effect of Gas Content and Actual Stresses on Coalbed Permeability. Journal of Mining Science. 2016. Vol. 52. № 2. pp 218–225. DOI: 10.1134/S1062739116020345
10. Averin A.P., Belousov F.S., Pashichev B.N., Trofimov V.A. Gas flow patterns in rock samples. Gornyy informatsionno-analiticheskiy byulleten (nauchno-tekhnicheskiy zhurnal) = Mining Informational and Analytical Bulletin (Scientific and technical journal). 2021. № 10. pp. 100–111. (In Russ.).
11. Shelukhin V.V., Krutko V.V., Trusov K.V. Filtration of highly miscible liquids based on two-scale homogenization of the Navier — Stokes and Cahn — Hilliard equations. Prikladnaya mekhanika i tekhnicheskaya fizika = Journal of Applied Mechanics and Technical Physics. 2023. Vol. 64. Iss. 3. pp. 161–173. (In Russ.). DOI:
12. Koshlyakov N.S., Gliner E.B., Smirnov M.M. Equations in partial derivatives of mathematical physics. Moscow: Vysshaya shkola, 1970. 712 p. (In Russ.).
DOI: 10.24000/0409-2961-2024-1-44-50
Year: 2024
Issue num: January
Keywords : coal seam gas-air mixture filtration process excavation with long pillars air suctions filtration theory boundary value problem filtration rate coal self-heating
  • Cherdantsev S.V.
    Dr. Sci. (Eng.), Chief Research Associate, AO «NTs VostNII», Kemerovo, Russia
  • Shlapakov P.A.
    Cand. Sci. (Eng.), Laboratory Head AO «NTs VostNII», Kemerovo, Russia
  • Kolykhalov V.V.
    Senior Research Assistant AO «NTs VostNII», Kemerovo, Russia
  • Khaymin S.A.
    Senior Research Assistant, Scientific Centre VostNII for Industrial and Environmental Safety in Mining Branch, Kemerovo, Russian Federation