Abstract
Energy requirement is mostly met by coal in India. Open-pit mining majorly contributes to coal production. Availability of land for waste dumping is a serious bottleneck in expansion of open-pit projects. Due to scarcity of land, mixing of some soft soil or clay within the overburden is common. In several places dump failures have occurred due to the presence of weak clay or soil mixed in the overburden dumps. In this study, numerical modelling has been conducted using a Finite difference numerical modelling software FLAC3D to assess the effect of mixing weak soil or clay of various proportions on the overall stability of an overburden dump. To incorporate the unknown random effect of weak soil placement in the overburden, a spatial probabilistic method was applied to randomise the material properties in the overburden dump. For each combination of percentage of weak material and the dump height studied, 100 models were run, and the factor of safety was analysed using probability density plots and normal distribution graphs. From the range of FOS obtained from the modelling, the lower limit of FOS with 95% reliability has been determined. The analysis revealed that the FOS dropped quite significantly due to the presence of weak soil, and in some cases, the dumps might require redesigning to avert a failure.
This is a preview of subscription content, log in via an institution to check access.
References
Mukherjee S, Pahari DP (2019) Underground and opencast coal mining methods in India: a comparative assessment. Sp Cult India 7:39–55. https://doi.org/10.20896/saci.v7i1.395
Sekhar S, Singh UC, Porathur JL, Budi G (2021) Overburden dump stabilization over weak floor using rock-filled trench near the toe—a numerical modeling approach. Arab J Geosci 14(4):1–7
Radhakanta K, Debashish C (2010) Discrete element approach for mine dump stability analysis. Min Sci Technol 20:809–813. https://doi.org/10.1016/S1674-5264(09)60286-6
Kainthola A, Verma D, Gupte SS, Singh TN (2011) A coal mine dump stability analysis—a case study. Geomaterials 01:1–13. https://doi.org/10.4236/gm.2011.11001
Koner R (2021) Estimation of optimum geometric configuration of mine dumps in Wardha valley coalfields in India a case study. J Min Environ. https://doi.org/10.22044/JME.2021.10979.2074
Poulsen B, Khanal M, Rao AM, Adhikary D, Balusu R (2014) Mine overburden dump failure: a case study. Geotech Geol Eng 32:297–309. https://doi.org/10.1007/s10706-013-9714-7
Coal mine regulations (2017) Ministry of Labour and employment notification. The gazette of India. https://www.dgms.net/Coal%20Mines%20Regulation%202017.pdf. Accessed 20 July 2021
Singh TN, Barde KS, Purwar N, Gupta S, Sarkar K (2007) Assessing stability of waste dump—a case study. In: Tenth international symposium on environmental issues and waste management in energy and mineral production. Thailand, pp.769–779
Sharma A, Rai R, Srivastava BK (2011) Stability analysis of internal mine waste dump by numerical simulation. Indian J Min Eng 50(11):232–238
Pradhan SP, Vishal V, Singh TN, Singh VK (2014) Optimisation of dump slope geometry vis-à-vis fly ash utilisation using numerical simulation. Am J Min Metall 2(1):1–7
Behera KP, Sarkar K, Singh AK, Verma AK, Singh TN (2016) Dump slope stability analysis-a case study. J Geol Soc India 88(6):725–735
Choudhury PK, Das A, Goswami DN, Sanyal T (2008) Bio-engineering approach with jute Geotextile for slope stabilization. In: Geosynth civ environ eng—Geosynth Asia 2008 proc 4th Asian reg conf geosynth, pp 863–867. https://doi.org/10.1007/978-3-540-69313-0_156
Upadhyay OP, Sharma DK, Singh DP (1990) Factors affecting stability of waste dumps in mines. Int J Surf Min Reclam Environ 4:95–99. https://doi.org/10.1080/09208119008944174
Koner R, Chakravarty D (2016) Numerical analysis of rainfall effects in external overburden dump. Int J Min Sci Technol 26:825–831. https://doi.org/10.1016/j.ijmst.2016.05.048
Sazid M, Singh TN, Saharan MR (2012) Risk analysis of mine dump slope stability-a case study. Min Eng J 12:11–15
Firmanda G, Nayoan A G B (2021) Back analysis for landslide in mine waste dump slope using probabilistic analysis. In: Proc. the evolution of geotech: 25 years of innovation (held online) Hammah et al. (eds). Tylor Francis, pp 399–405
Itasca Consulting Group, Inc. (2012) FLAC3D—fast lagrangian analysis of continua in three dimensions, version. 5.0. Minneapolis: Itasca
Allan FC, Yacoub TE, Curran JH (2012) On using spatial methods for heterogeneous slope stability analysis. In: 46th US rock mechanics/geomechanics symposium held in Chicago, IL, USA, 24–27 June, 2012
Roy I, Roy A, Dutta S (2017) Prediction of safe and economic slope angles of external dumps of western coalfields limited. In: Proc. 7th Asian mining congress. pp 159–166
Rai R, Khandelwal M, Jaiswal A (2011) Application of geogrids in waste dump stability: a numerical modeling approach. Environ Earth Sci 66:1459–1465. https://doi.org/10.1007/s12665-011-1385-1
Acknowledgements
The authors would like to thank the Director of CSIR-Central Institute of mining and Fuel Research and Director of Indian Institute of Technology (Indian School of Mines) for the permission to publish this work. The views expressed are of the authors and not necessarily of the institute to which they belong.
Funding
This research received no financial support from any funding agencies.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of interest
There are no conflicts of interest.
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Singh, U.C., Sekhar, S., Porathur, J.L. et al. Effect of Scattered Dumping of Soft Soil in Coal Mine Overburden Dumps: A Probabilistic Analysis. Indian Geotech J 52, 735–741 (2022). https://doi.org/10.1007/s40098-022-00596-1
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s40098-022-00596-1