Authors

Affiliations

1 Hanoi University of Mining and Geology, Hanoi, Vietnam; lequangphuc@humg.edu.vn; lethithuha@humg.edu.vn; nguyenquoclong@humg.edu.vn

2 Research Group: Sustainable Development of Mining Science, Technology and Environment (SDM), Hanoi University of Mining and Geology, Hanoi, Vietnam; lequangphuc@humg.edu.vn

3 Innovations for Sustainable and Responsible Mining, Hanoi University of Mining and Geology, Hanoi, Vietnam; nguyenquoclong@humg.edu.vn

4 Geomatics in Earth Sciences Research Group, Hanoi University of Mining and Geology, Hanoi, Vietnam; lethithuha@humg.edu.vn

*Corresponding author: nguyenquoclong@humg.edu.vn; Tel.: +84–916196336

Abstracts

The presence of an overlying coal pillar (OCP) strongly influences the stress distribution and deformation of the surrounding rock of the roadway and working face. In this paper, the stress distribution characteristics under the coal pillar are analyzed through numerical simulation using the FLAC3D program. Multi-coal seam mining conditions at Thong Nhat coal mine were selected as the technical foundation. Research results show that the presence of coal pillars acts as a bridge to transfer loads from the roof rock strata to the floor, and therefore it forms a high-stress concentration zone with an oval shape under the coal pillar. Caused by stress superposition, abutment stress distribution rules are affected by the distance from the roadway or working face to the OCP. In the concentrated stress zone of the OCP, the abutment pressure at the roof and floor of the roadway increases by 2 times and puts the road into a dangerous deformation condition. Meanwhile, when the working face approaches the OCP, the front abutment pressure value increases 1.3 times, and the range of the high-stress zone increases 2 times. Thus, the presence of OCP has changed the stress distribution law in the direction of increasing the value and distribution range of the maximum stress area, and it affects the roadway and working face of the coal seam below. The research results of this article will be an important document as a basis for researching technical solutions to meet the requirements for safe mining in underground coal mines.

Keywords

Cite this paper

Phuc, L.Q.; Ha, L.T.T.; Long, N.Q. Stress distribution under coal pillars in the case of multi-seam mining: A case study at Thong Nhat Coal Mine, VietnamJ. Hydro-Meteorol. 202420, 15-23.

References

1. Zhang, Z.; Deng, M.; Bai, J.; Yan, S.; Yu, X. Stability control of gob-side entry retained under the gob with close distance coal seams. Int. J. Min. Sci. Technol. 202131(2), 321–332.

2. Ju, J.F.; Hu, G.L. Influence of leading instability in the upper dip coal pillar boundary to the strong strata behaviors during the working face out of the pillar. J. China Coal Society. 201237(7), 1080–1087.

3. Liu, C.Y.; Yang, J.X.; Liu, J.R. Mechanism of strong pressure reveal under the influence of mining dual system of coal pillar in Datong mining area. J. China Coal Society. 201439(1), 40–46.

4. Lei, X.U.; Hailiang, Z.; Dongkun, G.; Bo, L.I. Principal stress difference evolution in floor under pillar and roadway layout. J. Min. Saf. Eng. 201532(3), 478.

5. He, Y.; Huang, Q.; Ma, L.; Wang, Q.; Fan, D. Research on roof weighting mechanism of coal pillar mining in shallow buried closely spaced multi-seams. 2023.

6. Xia, B.; Jia, J.; Yu, B.; Zhang, X.; Li, X. Coupling effects of coal pillars of thick coal seams in large-space stopes and hard stratum on mine pressure. Int. J. Min. Sci. Technol2017, 27(6), 965–972.

7. Huang, Q.; Du, J.; Chen, J.; He, Y. Coupling control on pillar stress concentration and surface cracks in shallow multi-seam mining. Int. J. Min. Sci. Technol. 202131(1), 95–101.

8. Cheng, W.; Nong, Z.; Guichen, L.; Nianchao, Z. De-stressed mining of multi-seams: Surrounding rock control during the mining of a roadway in the overlying protected seam. Min. Sci. Technol. 201121(2), 159–164.

9. Mu, H.; Bao, Y.; Song, D.; Su, D. Investigation of strong strata behaviors in the close-distance multiseam coal pillar mining. Shock Vib. 2021, 1–14.

10. Huang, Q.; Du, J.; Chen, J.; He, Y. Coupling control on pillar stress concentration and surface cracks in shallow multi-seam mining. Int. J. Min. Sci. Technol. 2021, 31(1), 95–101.

11. Yuan, L. Technique of coal mining and gas extraction without coal pillar in multi-seam with low permeability. J. Coal Sci. Eng. 2009, 15(2), 120–128.

12. Mu, H.; Wang, A.; Song, D.; Su, D.; Li, D. Failure mechanism of gob-side roadway under overlying coal pillar multiseam mining. Shock Vib. 2021, 1–13.

13. Tati, B. Multi-seam coal mining. J. South. Afr. Inst. Min. Metall. 2011, 111(4), 231–242.

14. Huang, Q.; Cao, J. Research on coal pillar malposition distance based on coupling control of three-field in shallow buried closely spaced multi-seam mining, China. Energies 2019, 12(3), 462.

15. Ghosh, N.; Agrawal, H.; Singh, S.K.; Banerjee, G. Optimum chain pillar design at the deepest multi-seam longwall workings in India. Min. Metall. Explor. 2020, 37, 651–664.

16. Tian, C.; Yang, X.; Sun, H.; Liu, Y.; Hu, Q. Experimental study on the overburden movement and stress evolution in multi‐seam mining with residual pillars. Energy Sci. Eng. 2019, 7(6), 3095–3110.

17. Zhu, Z.; et al. Overburden movement characteristics of top-coal caving mining in multi-seam areas. Q. J. Eng. Geol. Hydrogeol. 2018, 51(2), 276–286.

18. He, Y.; et al. Research on roof weighting mechanism of coal pillar mining in shallow buried closely spaced multi-seams, 2023.

19. ITASCA. Fast Lagrangian Analysis of Continua User’s Guide; Itasca Consulting Group Inc.: Minneapolis, MN55401, USA. 2019. https://www.itascacg.com/search.

20. Phuc, L.Q. Cause and solution to roadway deformation in Vietnam underground coal mines. Inżynieria Mineralna 2021, 2(1), 381–390.