Assessment of Spontaneous Ignition Lability and Gas Evolution of Coal-Bearing Rocks of Dumps and Sludges of the Coal Enterprises


Annotation:

Rock dumps of coal mining and coal processing enterprises contain coal, which is capable to absorbing oxygen to generate heat. Under favorable conditions, the heat generated is sufficient to increase the rock temperature and to form spontaneous fire seats. At the same time, coal-bearing rocks emit combustible and toxic gases generated during the coal decay and the oxidation of combustible elements. 
To assess the possibility of the development of spontaneous ignition processes in the coal-bearing rock agglomerates that were exposed to air for a long time, the samples were taken, the constant oxygen sorption rate and the duration of the spontaneous ignition incubation period were determined. Sampling was carried out on the surface of two dumps of the open pits, as well as at different depths of the slimepit of the processing plant, which were not in operation for decades. The experiment allowed to determine the concentration and intensity of the evolution of various gases from the coal-bearing rocks at natural ambient temperature. 
The uneven sorption activity of the rocks on the surface of dumps contributes to forming spontaneous fire seats in the areas that are most liable to this. In addition, rock dumps for decades continue to emit methane and carbon monoxide into the atmosphere at the natural temperature of the rocks, which negatively affects the surrounding nature. In the sludge settling tank, not operated for about 60 years, the sorption activity of the sludge in relation to oxygen changes not only on the surface, but also at different depths of the settling tank.
The revealed features of long-term storage of coal-bearing rocks in the dumps and slimepits should be taken into account when choosing the technologies for coal mining and processing, as well as storage of the overburden rocks and processing wastes.

References:
1. Kozyreva E.N., Nepeina E.S., Shinkevich M.V. Influence of temperature on the methane content of Kuznetsk Basin coking coal. Koks i khimiya = Coke and Chemistry. 2018. № 3. pp. 38–42. (In Russ.).
2. Akhmetgareev R.A., Fedorov E.V. About the Standards of Gas Content Identification in Coal. Bezopasnost truda v promyshlennosti = Occupational Safety in Industry. 2015. № 11. pp. 30–35. (In Russ.).
3. Kozyreva E.N., Shinkevich M.V. The peculiarities of structurizing enclosing rock massif while developing a coal seam. IOP Conference Series: Earth and Environmental Science. 2017. Vol. 84. pp. 1–6. DOI: 10.1088/1755-1315/84/1/012007
4. Portola V.A., Torosyan E.S., Antufeyev V.K. Radon Emission from Coal Mines of Kuzbass Region. IOP Conference Series: Materials Science and Engineering. 2016. Vol. 127. pp. 1–5. DOI: 10.1088/1757-899X/127/1/012021
5. Levkin N.D., Mukhina N.E. Influence of coal mines rock dumps on the state of environment. Aktualnye problemy gumanitarnykh i estestvennykh nauk = Actual problems of the humanities and natural sciences. 2011. № 5. pp. 277–279. (In Russ.).
6. Portola V.A., Protasov S.I., Podobrazhin S.N. Problems and ways of reducing the hazard in the open-pit coal mining. Bezopasnost truda v promyshlennosti = Occupational Safety in Industry. 2004. № 11. pp. 41–43. (In Russ.).
7. Kachurin N.M., Vorobev S.A., Ribak L.L., Sidorov R.V. Heat-mass exchange processes in waste dumps of Kuznetsk Basin mines. Izvestiya Tulskogo gosudarstvennogo universiteta. Nauki o Zemle = Izvestiya Tula State University. Geosciences. 2015. № 2. pp. 48–56. (In Russ.).
8. Portola V.A., Skudarnov D.E., Protasov S.I., Podobrazhin S.N. Assessment of the Parameters of the Places of Spontanous Combustion of the Coal Pits Waste Dumps and the Ways of their Suppression. Bezopasnost truda v promyshlennosti = Occupational Safety in Industry. 2017. № 11. pp. 42–47. (In Russ.). DOI: 10.24000/0409-2961-2017-11-42-47
9. Skochinskiy A.A., Ogievskiy V.M. Mine fires. Moscow: Izd-vo «Gornoe delo» OOO «Kimmeriyskiy tsentr», 2011. 375 p. (In Russ.).
10. Veselovskiy V.S., Alekseeva N.D., Vinogradova L.N., Orleanskaya G.L., Terpogosova E.A. Spontaneous-combustion of industrial materials. Moscow: Nauka, 1964. 246 p. (In Russ.).
11. Portola V.A., Zhdanov A.N., Bobrovnikova A.A. The prospect of using antipyrogens to prevent spontaneous combustion of coal stores. Ugol = Coal. 2019. № 4 (1117). pp. 14–19. (In Russ.). DOI: 10.18796/0041-5790-2019-4-14-19
12. Lin Q., Wang S., Liang Y., Song S., Ren T. Analytical prediction of coal spontaneous combustion tendency: Velocity range with high possibility of self-ignition. Fuel Processing Technology. 2017. Vol. 159. pp. 38–47.
13. Liu W., Yueping Q., Xiaobin Y., Wenqiang W., Youqiang C. Early extinguishment of spontaneous combustion of coal underground by using dry-ice's rapid sublimation: A case study of application. Fuel. 2018. Vol. 217. pp. 544–552. DOI: 10.1016/j.fuel.2017.12.124
14. Su H., Zhou F., Li J., Qi H. Effects of oxygen supply on low-temperature oxidation of coal: A case study of Jurassic coal in Yima, China. Fuel. 2017. Vol. 202. pp. 446–454. DOI: 10.1016/j.fuel.2017.04.055
15. Yuan H., Restuccia F., Richter F., Rein G. A computational model to simulate self-heating ignition across scales, configurations, and coal origins. Fuel. 2019. Vol. 236. pp. 1100–1109. DOI: 10.1016/j.fuel.2018.09.065
16. Wang J., Zhang Y., Xue S., Wu J., Tang Y., Chang L. Assessment of spontaneous combustion status of coal based on relationships between oxygen consumption and gaseous product emissions. Fuel Processing Technology. 2018. Vol. 179. pp. 60–71. DOI: 10.1016/j.fuproc.2018.06.015
17. Zhang Y., Liu Y., Shi X., Yang C., Wang W., Li Y. Risk evaluation of coal spontaneous combustion on the basis of auto-ignition temperature. Fuel. 2018. Vol. 233. pp. 68–76. DOI: 10.1016/j.fuel.2018.06.052
18. Instructions for the prevention of spontaneous combustion, extinguishing and dismantling of the rock dumps. Ser. 05. Iss. 27. Moscow: ZAO NTTs PB, 2014. 40 p. (In Russ.).
DOI: 10.24000/0409-2961-2021-3-74-80
Year: 2021
Issue num: March
Keywords : rock dump centers of spontaneous-combustion endogenous fire oxygen sorption rate oxidation tendency to spontaneous-combustion шлам coal-bearing rocks gas evolution
Authors: