The Impact of Moisture Content on Outburst Hazard of Sandstones in Coal-Bearing Strata

Kostiantyn Andriiovych Bezruchko

Kostiantyn Andriiovych Bezruchko Institute of Geotechnical Mechanics named by N. Polja-kov of National Academy of Sciences of Ukraine

Keywords: Rock and gas outbursts, Prognosis, Carboniferous sandstones, Moisture, Porosity

Abstract

The article theorizes the impact of the quantitative moisture content in rocks with two main factors of outburst hazard – their physical and mechanical properties and the gas factor. The impact of natural humidity and reservoir properties of sandstones on the degree of their outburst hazard and the depth of outburst manifestation in coal mines of the Donetsk Basin (Ukraine) is researched. The exploration targets were outburst-prone sandstones of the Lower and Middle Carboniferous age of the coal-bearing strata of Donbas in Ukraine. Sandstones lay in zones of middle and late catagenesis, within the distribution of gas, fatty, and coking coals in the depth range of 700–1200 m. The author evaluated the absolute humidity (weight moisture indicator), relative humidity (water saturation or the degree of pore filling with moisture), and open porosity of researched sandstones. It has been established that the weight moisture/open porosity ratio determines the degree of outburst hazard of sandstones. This indicator is proposed as a prognostic criterion for determining the degree of outburst hazard of sandstones. A connection has also been established between the manifestation depth of sandstone and gas outbursts with their water and gas saturation. Based on determining the critical values for the degree of pore filling with moisture for fixed stratification depths, an evaluation method of outburst hazard is proposed. Testing the use of the proposed methods for determining the outburst hazard of rocks, considering the natural moisture of sandstones, in the mines of Donbas, fully confirmed their reliability, validity, and the possibility of practical application.

References

Baranov, V.А., 2021. Complex forecast of rock outburst hazard. Dnepr: Publisher Belaya Е.А., 300 pp (in Russian).

Bolshinsky, M.I., Lysikov, B.А., Kaplukhin, А.А., 2003. Gas-dynamic phenomena in mines. Sevastopol: Veber, 284 pp (in Russian).

Bukowska, M., Bukowski, P., 2023. Investigation of Geomechanical Properties of Carboniferous Rocks for Evaluating the Possibility of Energetic Use of Water and Methane from Hard Coal Mines. Arch. Min. Sci 68 (2), 207-225. https://doi.org/10.24425/ams.2023.146176.

Bulat, A.F., Bezruchko, K.A., 2015. System water—gas in the massif of rocks of Donbas, Kyiv, Naukova Dumka, 192 pp (in Russian).

Cherblanc, F., Berthonneau, J., Bromblet, P., Huon, V., 2016. Influence of Water Content on the Mechanical Behaviour of Limestone: Role of the Clay Minerals Content. Rock Mechanics and Rock Engineering 49, 2033-2042. https://doi.org/10.1007/s00603-015-0911-y.

Colback, S.B., Wiid, B., 1965. The influrns of moisture content on the compressive strength of rocks. Proc. Symp. on Rock Mechanics. Univ. Toronto Mines Branch, Dep. Mines, Ottawa, 65-83.

Khanin, A.A., 1968. Assessment of the screening ability of clayey rocks – seals of gas deposits. Geology of oil and gas, 9, 17 (in Russian).

Lama, R.D., Saghafi, A., 2002. Coal Operators’ Conference Tribute to Dr Ripu Daman Lama OVErview of Gas Outbursts and Unusual Emissions 6-8 February 2002. The AusIMM Illawarra Branch. https://outburst.uow.edu.au/presentations_publications/coal_2002-3/Lama%202002.pdf.

Majeed, Y., Abu Bakar, M.Z., 2018. Water Saturation Influences on Engineering Properties of Selected Sedimentary Rocks of Pakistan. Journal of Mining Science 54, 914-930. https://doi.org/10.1134/S1062739118065060.

Malkowski, P., A. Ulaszek, A., Ostrowski, L., 2014. Optimization of roof coal thickness in the roof of longwall face as a result of water inflow into roof rocks. Przegląd Górniczy 3, 48-57. https://doi.org/10.13140/2.1.3219.3289.

Özdemir, E., Eren Sarici, D., 2018. Combined Effect of Loading Rate and Water Content on Mechanical Behavior of Natural Stones. Journal of Mining Science 54, 931–937. https://doi.org/10.1134/S1062739118065072.

Petrov, Y.V., Smirnov, I.V., Volkov, G.A., Abramian, A.K., Bragov, A.M., Verichev, S.N., 2017. Dynamic failure of dry and fully saturated limestone samples based on incubation time concept. Journal of Rock Mechanics and Geotechnical Engineering 9, 125–134. https://doi.org/10.1016/j.jrmge.2016.09.004.

Price, N.J., 1960. The compressive strength of coal measure rocks. Colliery Engineering 37, 283-292.

Rutter, E.H., 1970. An Experimental study of the factors affecting the rheological properties of rock in simulated geological environment. London: Ph. D. Thesis, Imperial College, 89 pp.

Rutter, E.H., 1974. The influence of temperature, strain rate and interstitial water in the experimental deformation of calcite rocks. Tectonophysics 22, 311 pp.

Rutter, E.H., 1976. The kinetics of rock deformation by pressure solution. Philos. R. Sol. London, Ser. A 283, 203-213.

Shi, X., Cai, W., Meng, Y., Li, G., Wen, K., Zhang, Y., 2016. Weakening laws of rock uniaxial compressive strength with consideration of water content and rock porosity. Arabian Journal of Geosciences 9 (51), Article Number 369. https://doi.org/10.1007/s12517-016-2426-6.

Wong, L.N.Y., Maruvanchery, V., Liu, G., 2016. Water effects on rock strength and stiffness degradation. Acta Geotechnica 11, 713-737. https://doi.org/10.1007/s11440-015-0407-7.

Yao, Q., Li, X., Zhou, J., Ju, M., Chong, Z., Zhao, B., 2015. Experimental study of strength characteristics of coal specimens after water intrusion. Arabian Journal of Geosciences 8 (9), 6779-6789. https://doi.org/10.1007/s12517-014-1764-5.

Yilmaz, I., 2010. Influence of water content on the strength and deformability of gypsum. International Journal of Rock Mechanics and Mining Sciences 47 (2), 342–347. https://doi.org/10.1007/s00603-015-0911-y.

Zhang, D., Gamage, R.P., Perera, M.S.A., Zhang, C., Wanniarachchi, W.A.M., 2017. Influence of water saturation on the mechanical behaviour of low-permeability reservoir rocks. Energies 10 (236), 1-19. https://doi.org/10.3390/en10020236.

Zhou, Z., Cai, X., Cao, W., Li, X., Xiong, C., 2016. Influence of water content on mechanical properties of rock in Both saturation and drying processes. Rock Mechanics and Rock Engineering 49, 3009-3025. https://doi.org/10.1007/s00603-016-0987-z.