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American Journal of Mining and Metallurgy. 2014, 2(1), 17-22
DOI: 10.12691/ajmm-2-1-3
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A Comparative Study of Various Empirical Methods to Estimate the Factor of Safety of Coal Pillars

A. K. Verma1,

1Department of Mining Engineering, Indian School of Mines – Dhanbad-04, Jharkhand, India

Pub. Date: June 04, 2014

Cite this paper:
A. K. Verma. A Comparative Study of Various Empirical Methods to Estimate the Factor of Safety of Coal Pillars. American Journal of Mining and Metallurgy. 2014; 2(1):17-22. doi: 10.12691/ajmm-2-1-3


Design of coal pillars in a coal mine remains a challenge inspite of several theories proposed by several researchers over a period of time. India is heavily dependent on coal availability for supply of electricity to it’s billion of citizens. This has burdened the coal industry to increase the coal production which ultimately has lead to extraction of coal pillars also. Coal pillars are used to support the overlying roof rock to prevent it from falling. The dilemma with coal pillar stability is that On one hand, the size of the pillar should be as small as possible to enable maximum recovery of coal, while on the other hand, the pillar should be large enough to support the load of overlying strata. The stability of coal pillars has fascinated several researchers and hence many empirical equations have been proposed over the decades. In this paper, parameters like height of pillar, depth of pillar, compressive strength of coal, depth of the coal seam have been taken as input to estimate factor of safety of coal pillar from two mines i.e., Begonia and Bellampalli. It is found that Greenwald (1941), Salamon and Munro (1967), Sheorey (1992) and Maleki (1992) method has estimated failed cases correctly while Sheorey (1992) & Maleki (1992) have not predicted stable case of pillar correctly which is an interesting finding as empirical relations proposed by Sheorey (1992) is assumed to have good prediction in Indian condition.

Pillar strength factor of safety Begonia coal mines and Bellampalli coal mines percentage deviation

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