Mining of Mineral Deposits

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Effect of the quality indices of coal on its grindability

Denis Miroshnichenko1, Valentine Koval1, Olena Bogoyavlenska1, Serhiy Pyshyev2, Evgen Malyi3, Michael Chemerinskiy3

1National Technical University Kharkiv Polytechnic Institute, Kharkiv, Ukraine

2Lviv Polytechnic National University, Lviv, Ukraine

3Ukrainian State University of Science and Technologies, Dnipro, Ukraine

Min. miner. depos. 2022, 16(4):40-46

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      Purpose is to determine the effect of quality indices of coal characterized by different degrees of metamorphism as well as petrographic and ultimate composition on the values of its grindability defined by the Protodyakonov and Hardgrove methods.

      Methods. 14 coal samples being a part of the raw material base of coking and chemical enterprises of Ukraine were studied. In terms of the samples, the parameters of technical, petrographic, and ultimate analysis were identified. GOST 21153.1-75 Rocks. Method of determining the Protodyakonov strength coefficient and ISO 5074:2015 Bituminous coal. Determination of Hardgrove grindability index were used to identify coal grindability. Graphical and mathematical dependencies between the indices of coal quality (R0, Vdaf, Cdaf, Oddaf) and values of its grindability (f and HGI) were developed.

      Findings. The obtained mathematical and graphic dependencies of the effect of different indices of coal quality (R0, Vdaf, Cdaf, Oddaf) on the values of its grindability (f and HGI) were obtained. It is shown that dependence of coal quality indices with its strength coefficient (f) is much lower (R2 = 0.550-0.716) than with the Hardgrove grindability index (HGI): R2 = 0.807-0.937.

      Originality. For the first time, comparative measurements of coal grindability according to the Protodyakonov and Hardgrove methods have been performed. It has been identified that the value of these indices are inversely proportional and described by a second-order polynom.

      Practical implications. The obtained graphical and mathematic dependencies can be used to predict the operation of crushing equipment for both individual coal and the one of different grade and ultimate composition at coking-chemical and heat-producing enterprises.

      Keywords: coal, volatile matter content, macerals, metamorphism, crushing, vitrinite, grindability


  1. The results of the Mining and Metallurgical Complex of Ukraine for 12 months of 2021. Retrieved from:
  2. Chernyavskyy, M.V., & Miroshnichenko, Ye.S. (2021). Changes in the structure of electricity generation in Ukraine and prospects of thermal energy development. Proceedings of the XVII International Scientific and Practical Conference “Coal Heat: Ways of Reconstruction and Development”, 31-38.
  3. Miroshnichenko, D. (2013). Crushing properties of coal. Coke and Chemistry, (56), 449-455.
  4. Shmeltser, E., Lyalyuk, V., Sokolova, V., Miroshnichenko, D. (2017). Influence of the crushing of bituminous batch on coke quality. Coke and Chemistry, (60), 470-475.
  5. Meniovich, B.I., Pinchuk, S.I., & Dyukanov, A.G. (1985). Povyshenie effektivnosti protsessa sloevogo koksovaniya. Kiev, Ukraina: Tehnika, 229 s.
  6. Zhao, J., Liu, J., Li, M., & Hou, J. (2022). Study on micro-energy consumption model of ultrafine grinding coal particles. Fuel, (329), 125542.
  7. Mangi, H.N., Chi, R., DeTian, Y., Sindhu, L., Lijin, He, D., Ashraf, U., Fu, H., Zixuan, L., Zhou, W., & Anees, A. (2022). The ungrind and grinded effects on the pore geometry and adsorption mechanism of the coal particles. Journal of Natural Gas Science and Engineering, (100), 104463.
  8. Chipakwe, V., Semsari, P., Karlkvist, T., Rosenkranz, J., Chelgani, S.Ch. (2020). A critical review on the mechanisms of chemical additives used in grinding and their effects on the downstream processes. Journal of Materials Research and Technology, (9), 8148-8162.
  9. Tretyakova, M.V., & Linnik, Ju.N. (2017). The approach to assessing the efficiency of organizations of fuel-energy complex. Safety and Reliability of Power Industry, 10(1), 18-25.
  10. Zhang, S., & Mao, W. (2017). Energy efficiency optimization of coal conveying systems with consideration of crushers. Energy Procedia, (105), 3253-3261.
  11. Hansen, A.E., & Hower, J.C. (2014). Notes on the relationship between microlithotype composition and Hardgrove grindability index for rank suites of Eastern Kentucky (Central Appalachian) coals. International Journal of Coal Geology, 131(1), 109-112.
  12. Hower, J.C., Bagherieh, A.H., Dindarloo, S.R., Trimble, A.S., & Chelgani, S.C. (2021). Soft modeling of the Hardgrove grindability index of bituminous coals: An overview. International Journal of Coal Geology, (247), 103846.
  13. Matin, S.S., Hower, J.C., Farahzadi, L., & Chehreh Chelgani, S. (2016). Explaining relationships among various coal analyses with coal grindability index by Random Forest. International Journal of Mineral Processing, (155), 140-146.
  14. Dindarloo, S., Hower, J.C., Bagherieh, A., & Trimble, A.S. (2016). Fundamental evaluation of petrographic effects on coal grindability by seasonal autoregressive integrated moving average (SARIMA). International Journal of Mineral Processing, (154), 94-99.
  15. Bu, X., Chen, Y., Ma, G., Sun, Y., Ni, C., & Xie, G. (2020). Wet and dry grinding of coal in a laboratory-scale ball mill: Particle size distributions. Powder Technology, (359), 305-313.
  16. GOST 21153.1-75. (1975). Rocks. Method for the determination of strength factor according to Protod’yakonov.
  17. ISO 5074:2015. (2015). Hard coal – Determination of Hardgrove grindability index. Retrieved from:
  18. Eremin, I.V., Artser, A.S., & Bronovets, T.M. (2020). Petrologiya i khimiko-tekhnologicheskie parametry uglei Kuzbassa. Kemerovo, Rossiya: Pritomskoe, 399 s.
  19. Waters, A. (1986). The additive relationship of Hardgrove grindability index. Journal of Coal Quality, 5(1), 33-34.
  20. Trimble, A.S., & Hower, J.C. (2003). Studies of the relationship between coal petrology and grinding properties. International journal of Coal Geology, (54), 253-260.
  21. Bagherieh, A.H., Hower, J.C., & Bagherieh, A.R. (2008). Studies of the relationship between petrography and grindability for Kentucky coals using artificial neural network. International Journal of Coal Geology, (73), 130-138.
  22. Лицензия Creative Commons