Skip to main content
SpringerLink
Log in

Dynamic sublevel caving technology for thick seams with large dip angle in longwall top coal caving (LTCC)

  • Original Report
  • Published:
Granular Matter Aims and scope Submit manuscript

Abstract

Dynamic sublevel caving technology (DSCT) proposed by the researchers is one of effective methods to solve the problems of low top coal recovery, poor drawing balance and support stability in longwall top coal caving (LTCC) with large dip angle. To investigate the reasonable number of supports in a sublevel (N) and the top coal drawing mechanisms under DSCT, this research takes Panel 7401 in Zouzhuang Coal Mine as the geological background. Firstly, the optimal threshold value of N is theoretically analyzed, and the numerical simulations of drawing experiments under different Ns are calculated. The results show that when N = 3, the top coal recovery is the highest, the number of excessive drawing top coal at the upper end is relatively small, and the drawing balance is great, which is conducive to improving the resource recovery and safety management. With increasing N, the over-development of right top coal boundary towards the upper end increases, the range of coal ridge in the lower sublevel also gradually increases, while the strong force chain area at the upper end gradually decreases, resulting in the support stability becoming worse. In addition, the displacement of top coal at the upper end gradually increases with increasing N, and the permanent loss feature of residual top coal exists in the upper sublevel. The field top coal recovery under DSCT was measured finally, obtaining that DSCT can improve the top coal recovery by about 5% and promote the stability and working efficiency of the support. The research results have great theoretical and guiding significance for the high yield and high efficiency LTCC technology for thick coal seam with large dip angle.

Graphical Abstract

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13
Fig. 14
Fig. 15

Similar content being viewed by others

References

  1. Wang, G.F.: Development of fully mechanized top coal caving technology and new hydraulic support for top coal caving. J. Min. Strata Control Eng. 4, 18–20 (1996)

    Google Scholar 

  2. Gao, Y.J.: Design and stress analysis of hydraulic support with high drawing opening. China Coal 9, 33–35 (2004)

    Google Scholar 

  3. Fu, Q., Yan, S.H., Wu, J.: Theoretical research on loose top-coal drawing of longwall sublevel caving mining. Chin. J. Rock Mech. Eng. 4, 568–572 (2002)

    Google Scholar 

  4. Yang, S.L., Wei, W.J., Zhang, J.W.: Top coal movement law of dynamic group caving method in LTCC with an inclined seam. Mining, Metall. & Explor. 37, 1545–1555 (2020)

    Google Scholar 

  5. Wang, J.C., Wei, W.J., Zhang, J.W.: Theoretical description of drawing body shape in an inclined seam with longwall top coal caving mining. Int. J. Coal Sci. Technol. 7, 182–195 (2020)

    Article  Google Scholar 

  6. Wang, J.C., Wei, W.J., Zhang, J.W., et al.: Stability analysis of support around the longwall top-coal caving mining in steeply thick coal seam. J. China Coal Soc. 42, 2783–2791 (2017)

    Google Scholar 

  7. Çelik, A., Özçelik, Y.: Investigation of the efficiency of longwall top coal caving method applied by forming a face in horizontal thickness of the seam in steeply inclined thick coal seams by using a physical model. Int. J. Rock Mech. Min. Sci. 148, 104917 (2021)

    Article  Google Scholar 

  8. Wu, J.: Theory and practice of sub-level caving method in China. J. China Coal Soc. 16, 1–11 (1991)

    Google Scholar 

  9. Wu, J., Zhang, Y.: Study on the basic theory of longwall top-coal caving system. J. China Univ. Min. Technol. 27, 332–335 (1998)

    Google Scholar 

  10. Wang, J.C., Fu, Q.: The loose medium flow field theory and its application on the longwall top-coal caving. J. China Coal Soc. 27, 337–341 (2002)

    ADS  Google Scholar 

  11. Wang, J.: Engineering practice and theoretical progress of top-coal caving mining technology in China. J. China Coal Soc. 43, 43–51 (2018)

    Google Scholar 

  12. Wang, J.C., Zhang, J.W.: BBR study of top-coal drawing law in longwall top-coal caving mining. J. China Coal Soc. 40, 487–493 (2015)

    Google Scholar 

  13. Zhang, J.W., Cheng, D.L., Yang, Y.C., et al.: Numerical and theoretical investigations of the effect of the gangue-coal density ratio on the drawing mechanism in longwall top-coal caving. Int. J. Coal Sci. Technol. 9, 31 (2022).

    Article  Google Scholar 

  14. Zhang, J.W., Wang, J.C., Wei, W.J.: Effect of face dip angle on the drawing mechanism in longwall top-coal caving mining. J. China Unversity Min. Technol. 47, 805–814 (2018)

    Google Scholar 

  15. Zhu, D.J., Chen, Z.H., Du, W.S., et al.: Caving mechanisms of loose top-coal in longwall top-coal caving mining based on stochastic medium theory. Arab. J. Geosci. 11, 621 (2018)

    Article  ADS  Google Scholar 

  16. Yu, B., Zhu, D., Chen, Z.: Top-coal drawing law of LTCC mining based on stochastic medium theory. J. China Coal Soc. 42, 1366–1371 (2017)

    Google Scholar 

  17. Wang, Z.H., Wang, J.C., Yang, S.L.: An ultrasonic-based method for longwall top-coal cavability assessment. Int. J. Rock Mech. Min. Sci. 112, 209–225 (2018)

    Article  Google Scholar 

  18. Le, T.D., Zhang, C.G., Oh, J., et al.: A new cavability assessment for longwall top coal caving from discontinuum numerical analysis. Int. J. Rock Mech. Min. Sci. 115, 11–20 (2019)

    Article  Google Scholar 

  19. Alehossein, H., Poulsen, B.A.: Stress analysis of longwall top coal caving. Int. J. Rock Mech. Min. Sci. 47, 30–41 (2010)

    Article  Google Scholar 

  20. Khanal, M., Adhikary, D., Balusu, R.: Evaluation of mine scale longwall top coal caving parameters using continuum analysis. Min. Sci. Technol. (China) 21, 787–796 (2011)

    Article  Google Scholar 

  21. Khanal, M., Adhikary, D., Balusu, R.: Prefeasibility study-Geotechnical studies for introducing longwall top coal caving in Indian mines. J. Min. Sci. 50, 719–732 (2014)

    Article  Google Scholar 

  22. Klishin, V.I., Fryanov, V.N., Pavlova, L.D., et al.: Modeling top coal disintegration in thick seams in longwall top coal caving. J. Min. Sci. 55, 247–256 (2019)

    Article  Google Scholar 

  23. Wei, W.J., Yang, S.L., Li, M., et al.: Motion mechanisms for top coal and gangue sizes in longwall top coal caving (LTCC) with an extra-thick seam. Rock Mech. Rock Eng. 55, 5107–5121 (2022)

    Article  Google Scholar 

  24. Wei, W.J., Wang, J.C., Zhang, J.W., et al.: Drawing mechanisms of granular top coal considering the structure of hydraulic support in longwall top coal caving. Bull. Eng. Geol. Environ. 82, 138 (2023)

    Article  Google Scholar 

  25. Wang, J.C., Wei, W.J., Zhang, J.W.: Effect of the size distribution of granular top coal on the drawing mechanism in LTCC. Granular Matter 21, 70 (2019)

    Article  Google Scholar 

  26. Wang, J.C., Wei, W.J., Zhang, J.W., et al.: Numerical investigation on the caving mechanism with different standard deviations of top coal block size in LTCC. Int. J. Min. Sci. Technol. 30, 583–591 (2020)

    Article  Google Scholar 

  27. Wang, J.C., Yang, S.L., Wei, W.J., et al.: Drawing mechanisms for top coal in longwall top coal caving (LTCC): A review of two decades of literature. Int. J. Coal Sci. Technol. 8, 1171–1196 (2021)

    Article  Google Scholar 

  28. Jangara, H., Ozturk, C.A.: Longwall top coal caving design for thick coal seam in very poor strength surrounding strata. Int. J. Coal Sci. Technol. 8, 641–658 (2021)

    Article  Google Scholar 

  29. Le, T.D., Oh, J., Hebblewhite, B., et al.: A discontinuum modelling approach for investigation of longwall top coal caving mechanisms. Int. J. Rock Mech. Min. Sci. 106, 84–95 (2018)

    Article  Google Scholar 

  30. Le, T.D., Bui, X.N.: Effect of key parameters on top coal first caving and roof first weighting in longwall top coal caving: A case study. Int. J. Geomech. 20, 04020037 (2020)

    Article  Google Scholar 

  31. Unver, B., Yasitli, N.E.: Modelling of strata movement with a special reference to caving mechanism in thick seam coal mining. Int. J. Coal Geol. 66, 227–252 (2006)

    Article  Google Scholar 

  32. Song, Z.Y., Konietzky, H.: A particle-based numerical investigation on longwall top coal caving mining. Arab. J. Geosci. 12, 556 (2019)

    Article  Google Scholar 

  33. Zhang, Q.L., Yue, J.C., Liu, C., et al.: Study of automated top-coal caving in extra-thick coal seams using the continuum-discontinuum element method. Int. J. Rock Mech. Min. Sci. 122, 104033 (2019)

    Article  Google Scholar 

  34. Zhang, Q.L., Yuan, R.F., Wang, S., et al.: Optimizing simulation and analysis of automated top-coal drawing technique in extra-thick coal seams. Energies 13, 232 (2020)

    Article  Google Scholar 

  35. Wang, J.C., Liu, F., Zhang, J.W.: Investigation on the propagation mechanism of explosion stress wave in underground mining. Geomach. Eng. 17, 297–307 (2019)

    Google Scholar 

  36. Yasitli, N.E., Unver, B.: 3D numerical modeling of longwall mining with top-coal caving. Int. J. Rock Mech. Min. Sci. 42, 219–235 (2005)

    Article  Google Scholar 

  37. Wang, J.C., Wei, W.J., Zhang, J.W., et al.: Laboratory and field validation of a LTCC recovery prediction model using relative size of the top coal blocks. Bull. Eng. Geol. Environ. 80, 1389–1401 (2020)

    Article  Google Scholar 

  38. Ghosh, A.K., Gong, Y.: Improving coal recovery from longwall top coal caving. J. Mines Met. Fuels 62, 51–57 (2014)

    Google Scholar 

  39. Song, Z.Y., Konietzky, H., Herbst, M.: Drawing mechanism of fractured top coal in longwall top coal caving. Int. J. Rock Mech. Min. Sci. 130, 104329 (2020)

    Article  Google Scholar 

  40. Wei, W.J., Song, Z.Y., Zhang, J.W.: Theoretical equation of initial top-coal boundary in longwall top-coal caving mining. Intern. J. Min. Miner. Eng. 9, 157–176 (2018)

    Article  Google Scholar 

  41. Yang, L., Li, L.H., Wei, W.J.: Optimization of caving technology in an extrathick seam with longwall top coal caving mining. Adv. Mater. Sci. Eng. 2021, 7725159 (2021)

    Article  Google Scholar 

  42. Yang, S.L., Zhang, J.W., Chen, Y., et al.: Effect of upward angle on the drawing mechanism in longwall top-coal caving mining. Int. J. Rock Mech. Min. Sci. 85, 92–101 (2016)

    Article  Google Scholar 

  43. Wang, J.C., Zhang, J.W., Li, Z.L.: A new research system for caving mechanism analysis and its application to sublevel top-coal caving mining. Int. J. Rock Mech. Min. Sci. 88, 273–285 (2016)

    Article  Google Scholar 

  44. Wang, J.C., Zhao, B.W., Zhao, P.F., et al.: Research on the longwall top-coal caving mining technique in extremely inclined and soft thick coal seam. J. China Coal Soc. 42, 286–292 (2017)

    Google Scholar 

  45. Wang, J.C., Chen, Y., Zhang, J.W.: Optimization study on drawing technique of longwall top coal caving in extrathick coal seam based on BBR system. Coal Eng. 48, 1–4 (2016)

    Google Scholar 

Download references

Acknowledgements

This work was supported by the National Natural Science Foundation of China (Grant no. 52204163), the National Key R&D Program of China (Grant no. 2022YFC2904001), the Young Elite Scientists Sponsorship Program by CAST (Grant no. 2022QNRC001), the Beijing Natural Science Foundation (Grant no. 2232059), the Fundamental Research Funds for the Central Universities (Grant no. 2023JCCXNY04), and the Open Fund of Key Laboratory of Safety and High-efficiency Coal Mining, Ministry of Education (Grant no. JYBSYS2021204).

Author information

Authors and Affiliations

  1. School of Energy and Mining Engineering, China University of Mining and Technology-Beijing, Beijing, 100083, China

    Wei Weijie, Pan Weidong, Zhang Jinwang, Zhao Zhining & Yang Liu

  2. Key Laboratory of Safety and High-Efficiency Coal Mining, Ministry of Education (Anhui University of Science and Technology), Huainan, 232001, China

    Zhang Xiangyang

  3. Coal Industry Engineering Research Center of Top-Coal Caving Mining, Beijing, 100083, China

    Wei Weijie, Pan Weidong, Zhang Jinwang, Zhao Zhining & Yang Liu

  4. Engineering Research Center for Green and Intelligent Mining of Thick Coal Seam, Ministry of Education, Beijing, 100083, China

    Wei Weijie, Pan Weidong, Zhang Jinwang, Zhao Zhining & Yang Liu

Authors
  1. Wei Weijie
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Pan Weidong
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Zhang Jinwang
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Zhao Zhining
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Yang Liu
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Zhang Xiangyang
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

WW: Conceptualization, methodology, writing-original draft preparation. PW: methodology, writing-reviewing and editing. ZJ: Supervision, Conceptualization, ZZ: Investigation, data curation. YL: Data curation. ZX: Supervision, writing-reviewing and editing.

Corresponding authors

Correspondence to Zhang Jinwang or Zhang Xiangyang.

Ethics declarations

Conflict of interest

The authors know that there is no conflict of interest concerning the publication of this technical note.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Weijie, W., Weidong, P., Jinwang, Z. et al. Dynamic sublevel caving technology for thick seams with large dip angle in longwall top coal caving (LTCC). Granular Matter 25, 56 (2023). https://doi.org/10.1007/s10035-023-01351-w

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1007/s10035-023-01351-w

Keywords

Search

Navigation