A FLAC3D based model has been developed to estimate the extent of coal wall spalling for a longwall face having a working depth of 406.5 m during the main weighting period. The results obtained from the model helped in characterizing two key phases of main weighting, namely, peak stress, and main fall period based on vertical stress concentration factor, percentage of yield zones, and extent of yielding ahead of the face. The maximum extent of coal wall spalling of 2 m was observed during the main fall period. Spalling is mainly concentrated near the upper-middle and the top sections of the face.
BaiQ, TuS, ChenM, ZhangC.2016. Numerical modeling of coal wall spall in a longwall face. Int J Rock Mech Min Sci. 88: 242 – 253. doi: 10.1016/j.ijrmms.2016.07.031.
2.
BaiQ, TuS, LiZ, TuH.2015. Theoretical analysis on the deformation characteristics of coal wall in a longwall top coal caving face. Int J Min Sci Technol. 25: 199 – 204. doi: 10.1016/j.ijmst.2015.02.006.
3.
BaiQ, TuS, ZhangX.2013. Numerical modeling on brittle failure of coal wall in longwall face – a case study. Arab J Geosci. 7: 5067 – 5080. doi: 10.1007/s12517-013-1181-1.
4.
BeheraB, YadavA, SinghGSP, SharmaSK.2019. Numerical modeling study of the geomechanical response of strata in longwall operations with particular reference to Indian geomining conditions. Rock Mech Rock Eng. doi: 10.1007/s00603-019-02018-w.
5.
BeheraB, YadavA, SinghGSP, SharmaSK.2020. A numerical modeling approach for evaluation of spalling associated face instability in longwall workings under massive sandstone roof. Eng Fail Anal. 117: 104927. doi: 10.1016/j.engfailanal.2020.104927.
6.
DasAJ, MandalPK, PaulPS, SinhaRK, TewariS.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. doi: 10.1007/s00603-019-01826-4.
7.
DasAJ, MandalPK, SahuSP, KushwahaA, BhattacharjeeR, TewariS.2018. Evaluation of the effect of fault on the stability of underground workings of coal mine through DEM and statistical analysis. J Geol Soc India. 92: 732 – 742. doi: 10.1007/s12594-018-1096-2.
8.
DasSK.2000. Observations and classification of roof strata behaviour over longwall coal mining panels in India. Int J Rock Mech Min Sci. 37: 585 – 597.
9.
MaheshwariP, MurmuS, VermaHK.2019. Modeling of blast induced damage distance for underground tunnels. Indian Geotech. Conf. 617 – 626. doi: 10.1007/978-981-33-6466-0_57.
10.
MandalPK, DasAJ, KumarN, BhattacharjeeR, TewariS, KushwahaA.2018. Assessment of roof convergence during driving roadways in underground coal mines by continuous miner. Int J Rock Mech Min Sci. 108: 169 – 178. doi: 10.1016/j.ijrmms.2018.06.001.
11.
MohanGM, SheoreyPR, KushwahaA.2001. Numerical estimation of pillar strength in coal mines. Int J Rock Mech Min Sci. 38: 1185 – 1192.
12.
MurmuS, BudiG.2019. Understanding the causes and geo-mechanics of longwall face instability. In Proceedings of: Recent Advances of Mining Technology, Bengaluru, p. 26–30.
13.
MurmuS, BudiG.2021. A probability-based risk assessment of roof strata weighting in longwall panels. Arabian J Geosci. 14: 362. doi: 10.1007/s12517-021-06637-y.
14.
MurmuS, MaheshwariP, VermaHK.2018. Empirical and probabilistic analysis of blast-induced ground vibrations. Int J Rock Mech Min Sci. 103: 267 – 274. doi: 10.1016/j.ijrmms.2018.01.038.
15.
PengSS.2006. Longwall mining. 2nd ed. Englewood: Society for Mining, Metallurgy, and Exploration, Inc. (SME).
16.
RaoS, DebD, KumarH.2016. Numerical analysis of a longwall mining cycle and development of a composite longwall index. Int J Rock Mech Min Sci. 89: 43 – 54. doi: 10.1016/j.ijrmms.2016.08.003.
17.
RayAK.2009. Influence of cutting sequence and time effects on cutters and roof falls in underground coal mine - numerical approach [MS thesis]. West Virginia University. doi: 10.33915/etd.3491.
18.
ShabanimashcoolM, LiCC.2012. Numerical modelling of longwall mining and stability analysis of the gates in a coal mine. Int J Rock Mech Min Sci. 51: 24 – 34. doi: 10.1016/j.ijrmms.2012.02.002.
19.
SheoreyPR.1994. A theory for In situ stresses in Isotropic and transversely Isotropic rock. Int J Rock Mech Min Sci Geomech Abstr. 31: 23 – 34.
20.
SheoreyPR.1997. Empirical rock failure criteria. 1st ed.Rotterdam: Balkema.
21.
SinghGSP, SinghUK.2009. A numerical modeling approach for assessment of progressive caving of strata and performance of hydraulic powered support in longwall workings. Comput Geotech. 36: 1142 – 1156. doi: 10.1016/j.compgeo.2009.05.001.
22.
SinghGSP, SinghUK.2010. Prediction of caving behavior of strata and optimum rating of hydraulic powered support for longwall workings. Int J Rock Mech Min Sci. 47: 1 – 16. doi: 10.1016/j.ijrmms.2009.09.001.
23.
SinghR, MandalPK, SinghAK, KumarR, SinhaA.2011. Coal pillar extraction at deep cover: with special reference to Indian coalfields. Int J Coal Geol. 86: 276 – 288. doi: 10.1016/j.coal.2011.03.003.
24.
SongG, ChughYP.2018. 3D analysis of longwall face stability in thick coal seams. J South African Inst Min Metall. 118: 131 – 142. doi: 10.17159/2411-9717/2018/v118n2a6.
25.
SongG, ChughYP, WangJ.2017. A numerical modelling study of longwall face stability in mining thick coal seams in China. Int J Min Miner Eng. 8: 35 – 55. doi: 10.1504/IJMME.2017.082682.
26.
TianM, HanL, XiaoH, MengQ.2021. Experimental study of deformations and failures of the coal wall in a longwall working face. Eng Fail Anal. 125: 105428. doi: 10.1016/j.engfailanal.2021.105428.
27.
WangJ, WangZ.2019. Systematic principles of surrounding rock control in longwall mining within thick coal seams. Int J Min Sci Technol. 29: 65 – 71. doi: 10.1016/j.ijmst.2018.11.014.
28.
XieGX, ChangJC, YangK.2009. Investigations into stress shell characteristics of surrounding rock in fully mechanized top-coal caving face. Int J Rock Mech Min Sci. 46: 172 – 181. doi: 10.1016/j.ijrmms.2008.09.006.
29.
YongY, ShihaoT, QiW, XiaotaoM, HongshengT, LuluS.2011. Mechanics of rib spalling of high coal walls under fully-mechanized mining. Min Sci Technol (China). 21: 129 – 133. doi: 10.1016/j.mstc.2010.12.014.
30.
ZhangL.2010. Estimating the strength of jointed rock masses. Rock Mech Rock Eng. 391 – 402. doi: 10.1007/s00603-009-0065-x.
