Abstract
Backfilling in goaf after pillar extraction seems to be a promising technology to help exploit these standing pillars. This paper presents the assessment of the impact of sand-stowing-based backfill on the peak strength and post-failure behavior of coal pillars. Rectangular coal samples were prepared and tested with different proportions of sand stowing, and a 3D finite-difference code was used for the numerical simulation to achieve the objective of the study. In laboratory experiments, the proportion of sand stowing was set at 0%, 60%, 70%, 80%, 90%, and 100% and tested in a servo-controlled machine, whereas, in numerical simulation, the percentage of sand stowing varied from 9 to 91% along with the coal pillar width-to-height ratios ranging from 1.5 to 5. The experimental and numerical results demonstrated that the average pillar strength increased as the proportion of stowing increased. The overall strength increased by 22% in the experimental study and about 28% to 32% in numerical simulation. The load vs. displacement characteristic changed from brittle to ductile as the sand proportion increases and the width-to-height ratio increased.
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References
Behera B, Yadav A, Singh GSP, Sharma SK (2020) Numerical modeling study of the geo-mechanical response of strata in longwall operations with particular reference to indian geo-mining conditions. Rock Mech Rock Eng 53:1827–1856. https://doi.org/10.1007/s00603-019-02018-w
Bobet A, Fakhimi A, Johnson S, Morris J, Tonon F, Yeung MR (2009) Numerical models in discontinuous media: review of advances for rock mechanics applications. J Geotech Geoenviron Eng 135:1547–1561. https://doi.org/10.1061/(asce)gt.1943-5606.0000133
Cheng B, Liu R, Li X, Castillo EDR, Chen M, Li S (2022) Effects of fly and coal bottom ash ratio on backfill material performance. Constr Build Mater 319:1–12. https://doi.org/10.1016/j.conbuildmat.2021.125831
Das AJ, Mandal PK, Ghosh CN, Sinha A (2017) Extraction of locked-up coal by strengthening of rib pillars with FRP—A comparative study through numerical modelling. Int J Min Sci Technol 27:261–267. https://doi.org/10.1016/j.ijmst.2017.01.024
Das AJ, Mandal PK, Paul PS, Sinha RK, Tiwari S (2019) Assessment of the strength of inclined coal pillars through numerical modelling based on the ubiquitous joint model. Rock Mech Rock Eng 52:3691–3717. https://doi.org/10.1007/s00603-019-01826-4
Feng G, Ran H, Guo J, Guo Y, Li C (2022) Experimental investigation on the deformation and strength properties of cemented gangue backfill column under long-term axial compression. Structures 43:1558–1572. https://doi.org/10.1016/j.istruc.2022.07.068
FLAC3D Manual. (2019) FLAC3D (Fast lagranggian analysis of continua in 3 dimensional). Version 6.0. Minneapolis USA
Gao F, Kang H (2017) Experimental study on the residual strength of coal under low confinement. Rock Mech Rock Eng 50:285–296. https://doi.org/10.1007/s00603-016-1120-z
Hou PY, Cai M, Zhang XW, Feng XT (2022) Post-peak stress-strain curves of brittle rocks under axial- and lateral-strain-controlled loadings. Rock Mech Rock Eng 55:855–884. https://doi.org/10.1007/s00603-021-02684-9
Jaiswal A, Shrivastva BK (2008) Numerical simulation of coal pillar strength. Int J Rock Mech Min Sci 46:779–788. https://doi.org/10.1016/j.ijrmms.2008.11.003
Jawed M, Sinha RK (2018) Design of rhombus coal pillars and support for Roadway Stability and mechanizing loading of face coal using SDLs in a steeply inclined thin coal seam—a technical feasibility study. Arab J Geosci 11:415–426. https://doi.org/10.1007/s12517-018-3747-4
Jiang Y, Wang H, Zhao Y, Jie Z, Xugeng P (2011) The influence of roadway backfill on bursting liability and strength of coal pillar by numerical investigation. Procedia Eng 26:1125–1143. https://doi.org/10.1016/j.proeng.2011.11.2283
Kejriwal B, Ghosh AK (1986) Effect of fill on the strength of coal pillars—an investigation. In: The 27th U.S. Symposium on rock mechanics (USRMS). Tuscaloosa, Alabama, pp 386–389
Kumar S, Kumar Sinha R, Jawed M (2022) Numerical simulation of depillaring panel at higher depth- Jamadoba mine case study. Ain Shams Eng J 14:1–10. https://doi.org/10.1016/j.asej.2022.101939
Li D, Zhang J, Sun Y, Li G (2021) Evaluation of rockburst hazard in deep coalmines with large protective island coal pillars. Nat Resour Res 30:1835–1847. https://doi.org/10.1007/s11053-020-09755-8
Li G, Deng G, Zhe Ma J (2022) Numerical modelling of the response of cemented paste backfill under the blasting of an adjacent ore stope. Constr Build Mater 343:1–12. https://doi.org/10.1016/j.conbuildmat.2022.128051
Mandal PK, Singh R, Maiti J, Sinha AK, Kumar R, Sinha A (2008) Underpinning-based simultaneous extraction of contiguous sections of a thick coal seam under weak and laminated parting. Int J Rock Mech Min Sci 45:11–28. https://doi.org/10.1016/j.ijrmms.2007.03.005
Mishra K, Paul PS, Ghosh CN, Singh P, Behra SK, Mandal PK (2022) Predicting and optimising the strength of cemented paste fills through bayesian network model. Mining, Metall Explor 39:2095–2120. https://doi.org/10.1007/s42461-022-00650-9
Mo S, Canbulat I, Zhang C, Oh J, Shen B, Hagan P (2018) Numerical investigation into the effect of backfilling on coal pillar strength in highwall mining. Int J Min Sci Technol 28:281–286. https://doi.org/10.1016/j.ijmst.2017.07.003
Nasharuddin R, Luo G, Robinson N, Fourie A, Johns ML, Fridjonsson EO (2022) Cemented paste backfill compressive strength enhancement via systematic water chemistry optimisation. Constr Build Mater 347:1–12. https://doi.org/10.2139/ssrn.4110670
Nasir O, Fall M (2010) Coupling binder hydration, temperature and compressive strength development of underground cemented paste backfill at early ages. Tunn Undergr Sp Technol 25:9–20. https://doi.org/10.1016/j.tust.2009.07.008
Salamon M, Munro A (1967) A study of the strength of coal pillars. JS Afr Inst Min Met 68:55–67
Sheorey PR (1997) Empirical rock failure criteria. Balkema, Rotterdam
Sheorey PR, Das MN, Barat D, Prasad RK, Singh B (1987) Coal pillar strength estimation from failed and stable cases. Int J Rock Mech Min Sci Geomech Abstr 24:347–355. https://doi.org/10.1016/0148-9062(87)92256-X
Singh AK, Singh R, Maiti J, Kumar R, Mandal PK (2011a) Assessment of mining induced stress development over coal pillars during depillaring. Int J Rock Mech Min Sci 48:805–818. https://doi.org/10.1016/j.ijrmms.2011.04.004
Singh R, Mandal PK, Singh AK, Kumar R, Sinha A (2011b) Coal pillar extraction at deep cover: With special reference to Indian coalfields. Int J Coal Geol 86:276–288. https://doi.org/10.1016/j.coal.2011.03.003
Sun Q, Zhang J, Zhou N (2018) Study and discussion of short- strip coal pillar recovery with cemented paste backfill. Int J Rock Mech Min Sci 104:147–155. https://doi.org/10.1016/j.ijrmms.2018.01.031
Sunkpal M, Sherizadeh T (2022) Exploring the deformation mechanics of coal ribs using the distinct element modeling approach. Rock Mech Rock Eng 55:2879–2898. https://doi.org/10.1007/s00603-021-02619-4
Tesarik DR, Seymour JB, Yanske TR (2003) Post-failure behavior of two mine pillars confined with backfill. Int J Rock Mech Min Sci 40:221–232. https://doi.org/10.1016/S1365-1609(02)00139-9
Wang H, Poulsen BA, Shen B, Xue S, Jiang Y (2011) The influence of roadway backfill on the coal pillar strength by numericalinvestigation. Int J Rock Mech Min Sci 48:443–450. https://doi.org/10.1016/j.ijrmms.2010.09.007
Yao Y, Cui Z, Wu R (2012) Development and challenges on mining backfill technology. J Mater Sci Res 1:73–78. https://doi.org/10.5539/jmsr.v1n4p73
York G (1998) Numerical modelling of the yielding of a stabilizing pillar/foundation system and a new design consideration for stabilizing pillar foundations. J S Afr Inst Min Metall 98:281–298
Zhang Q, Wang E, Feng X, Niu Y, Ali M, Lin S, Wang H (2020) Rockburst risk analysis during high-hard roof breaking in deep mines. Nat Resour Res 29:4085–4101. https://doi.org/10.1007/s11053-020-09664-w
Zhang Q, Wang E, Feng X, Wang C, Qiu L, Wang H (2021) Assessment of rockburst risk in deep mining: an improved comprehensive index method. Nat Resour Res 30:1817–1834. https://doi.org/10.1007/s11053-020-09795-0
Zhang C, Zhao Y, Han P, Bai Q (2022) Coal pillar failure analysis and instability evaluation methods: A short review and prospect. Eng Fail Anal 138:1–10. https://doi.org/10.1016/j.engfailanal.2022.106344
Zhao L (2021) Numerical investigation on the mechanical behaviour of combined backfill-rock structure with KCC model. Constr Build Mater 283:1–13. https://doi.org/10.1016/j.conbuildmat.2021.122782
Zhao Y, Guo Y, Feng G, Li C, Xie W, Zhang C (2022) Study on strength and deformation characteristics of cemented gangue backfill body under the coupling action of load and salt erosion. Constr Build Mater 342:1–13. https://doi.org/10.1016/j.conbuildmat.2022.128003
Acknowledgements
The authors would like to acknowledge the laboratory testing facilities provided by Rock Mechanics Laboratory, Department of Mining Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad, India. The authors also express their gratitude to the management of the underground coal mine for their assistance in collecting data for this study.
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Conceptualization, methodology, software, data/coal sample collection, writing—original draft preparation- S.K. Conceptualization, reviewing, methodology, and editing- R.K.S. and M.J. Model preparation, review—S.M.
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Kumar, S., Sinha, R.K., Jawed, M. et al. Assessment of coal pillar strength under the influence of sand stowing in deep coal mines. Geotech Geol Eng 42, 2815–2831 (2024). https://doi.org/10.1007/s10706-023-02707-y
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DOI: https://doi.org/10.1007/s10706-023-02707-y