Optimisation of Dump Slope Geometry Vis-à-vis Flyash Utilisation Using Numerical Simulation

S.P. Pradhan^1, , V. Vishal², T. N. Singh¹ and V.K. Singh²

¹Department of Earth Sciences, Indian Institute of Technology Bombay, Mumbai, India

²Mine Fire Division, CSIR-Central Institute of Mine and Fuel Research, Dhanbad, India

Cite this paper:
S.P. Pradhan, V. Vishal, T. N. Singh and V.K. Singh. Optimisation of Dump Slope Geometry Vis-à-vis Flyash Utilisation Using Numerical Simulation. American Journal of Mining and Metallurgy. 2014; 2(1):1-7. doi: 10.12691/ajmm-2-1-1

Abstract

Stability of waste dump is now gaining importance due to increasing depth and size of mine. Management of dump nearby mining areas is one of the most critical and crucial task for mine management due to limited land and other governing laws related to environment and forest conservation. In this paper, a study was conducted to establish the effect of slope angle on the stability of waste dump for accommodation of flyash is carried out. Based on numerical simulation, it was found that the dump slope of 60 m height with 36° slope can be critically stable with 20% flyash randomly mixed with overburden materials whereas flatter slopes provide higher factor of safety. Keeping other parameters constant, the optimum slope of 32° is the best possible to accommodate the mine dump for its long term stability. These findings were further supported by study of maximum velocity vectors and shear strain rates in every case and the extent of damage zone due to tensile pull. It is hoped that this technical note will find utility wherever a design of dump of chosen material type is being planned where the wastes can be managed alongside ulitisation of flyash.

Keywords:
dump dump slope factor of safety (FoS) finite difference method (FDM) FLAC/Slope

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References:

[1]	Bishop, A W, The stability of tips and soil heaps. Quarterly Journal of Engineering Geology & Hydrogeology, Vol. 6, Nos. 3 & 4, 1973, pp. 335-376.
[2]	Chang, Y L and Huang, T K, Slope stability analysis using strength reduction technique. Journal of the Chinese Institute of Engineers, Vol. 28, No. 2, 2005, pp. 231-240.
[3]	Cundall, P, Explicit finite difference methods in geomechanics. In Numerical Methods in Engineering, Proceedings of the International Conference on Numerical Methods in Geomechanics, Blacksburg, Vol. 1, 1976, pp. 132-150.
[4]	Dawson, E M, Roth, W H and Drescher, A, Slope stability analysis by strength reduction. Géotechnique, Vol. 49, No. 6, 1999, pp. 835-840.
[5]	Girard, J M and McHugh, E, Detecting problems with mine slope stability. In: 31st Annual Institute on Mining Health, Safety, and Research, Roanoke, VA, 2000.
[6]	Han, J and Leshchinsky, D, Limit equilibrium and continuum mechanics based numerical methods for analyzing stability of MSE walls. Proceedings of the 17th Engineering Mechanics Conference, ASCE, 2004.
[7]	Hebil, K E, Spoil pile stabilization at the Paintearth mine, Forestburg, Alberta. International Symposium on Geotechnical Stability in surface mining, Calgary, Canada, Vol. 181, 1986, pp. 8.
[8]	ISRM, Commission on Standardization of Laboratory and Field Tests, Suggested methods for the quantitative description of discontinuities in rock masses. International Journal of Rock Mechanics and Mining Science & Geomechanical Abstracts, Vol. 15, 1978, pp. 319-368.
[9]	ISRM, Rock Characterization Testing and Monitoring. ISRM Suggested Methods, International Society for Rock Mechanics, Pergamon Press, 1981, pp. 211.
[10]	Itasca, FLAC/SLOPE Users’ Guide. Itasca Consulting Group, Command Reference, FISH and Theory and Background, Minneapolis, 1995.
[11]	Janbu, N, Discussion of dimensionless parameters for homogeneous Earth. Journal of the Soil Mechanics and Foundations Division, ASCE, Vol. 93, No. SM6, 1967, pp. 367-374.
[12]	Kuraz, V, Soil properties and water regime of reclaimed surface dumps in the North Bohemian brown-coal region - a field study. Waste Management, Vol. 21, 2001, pp. 147-151.
[13]	Lakshmikantha, H, Report on waste dump sites around Bangalore. Waste Management, Vol. 26, 2006, pp. 640–650.
[14]	Monjezi, M and Singh, T N, Slope Instability in an Opencast Mine. Coal International, 2000, pp. 145-147.
[15]	Pradhan, S P, Vishal, V and Singh, T N, Stability of slope in an open cast mine in Jharia coalfield, India -A Slope Mass Rating approach. Mining Engineers’ Journal, Vol. 12 No. 10, 2011, pp. 36-40.
[16]	Pradhan, S P, Vishal, V and Singh, T N, Influence of bio-stabilisation on dump slopes-A discrete element modeling approach. 47th US Rock Mechanics / Geomechanics Symposium, San Francisco, USA. 2013, ARMA-736.
[17]	Rai, R and Singh, T N, Cost benefit and its environmental impact in mining. Journal of Industrial Pollution Control, 20, No. 1, 2004, pp. 17-24.
[18]	Sarkar, K, Vishal, V and Singh, T N, 2012. An empirical correlation of index geomechanical parameters with the compressional wave velocity. Geotechnical and Geological Engineering.
[19]	Singh, T N and Chaulya, S K, External dumping of overburden in open cast mine. Indian Journal of Engineers, Vol. 22, Nos. 1 & 2, 1992, pp. 65-73.
[20]	Singh, T N and Monjezi, M, Slope Stability Study in Jointed Rockmass - A Numerical Approach. Mining Engineering Journal, Vol. 1, No. 10, 2000, pp. 12-13.
[21]	Singh, T N, Chaulya, S K and Singh, J, Effect of mine waste disposal on environment and its protection. Eurock 93, Lisbon, Portugal, 1993, pp. 283-391.
[22]	Singh, T N, Pradhan, S P and Vishal, V, Stability of slopes in a fire-prone mine in Jharia Coalfield, India. Arabian Journal of Geosciences, Vol. 6, No. 2, 2013, pp. 419-427.
[23]	Swati, M and Joseph, K, Settlement analysis of fresh and partially stabilised municipal solid waste in simulated controlled dumps and bioreactor landfills. Waste Management, Vol. 28, 2008, pp. 1355-1363.
[24]	Turer, D and Turer, A, A simplified approach for slope stability analysis of uncontrolled waste dumps. Waste Management and Research, Vol. 29, 2011, pp. 146-156.
[25]	Vishal, V, Pradhan, S P and Singh, T N, Instability assessment of mine slope-A Finite Element Approach. International Journal of Earth Sciences and Engineering, Vol. 3, 2010, pp. 11-23.
[26]	Vishal, V, Pradhan, S P and Singh, T N, Mine sustainable development vis-a-vis dump stability for a large open cast mine. Proceedings of International Conference on Earth Sciences and Engineering, 2010, pp. 7-14.
[27]	Vishal, V, Pradhan, S P and Singh, T N, Tensile strength of rock under elevated temperature. Geotechnical and Geological Engineering Vol. 29, 2011, pp. 1127-1133.
[28]	Watters, R J, Influence of internal water and material properties on mine dump stability. Geological Society of America Abstracts with Programs, Vol. 37, No. 7, 2005, pp. 394.