Pillar strength approaches based on a new failure criterion for coal seams

Sheorey, P.R.; Das, M.N.; Bordia, S.K.; Singh, B.

doi:10.1007/bf01552957

Cited by 24 publications

(7 citation statements)

References 4 publications

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“…To ensure the long-term stability of a coal pillar, if the coal seam is weak, the ratio should be larger than 0.65 [ 67 , 68 ]. If the safety factor is larger than 1.6, it can ensure the long-term stability of the coal pillars [ 69 , 70 ].…”

Section: Coal Seam #2 Mining After the Double Strip Mining In The Undmentioning

confidence: 99%

The pressure relief protection effect of different strip widths, dip angles and pillar widths of an underside protective seam

et al. 2021

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To design underside protective seam strip layout. Similarity model experiments, numerical simulations and theoretical calculations are used to quantitatively study the pressure relief protection effect of different strip widths, dip angles and coal pillar widths of a thin underside protective seam under deeply buried conditions. The optimal strip width range is obtained according to the change law of strain during the mining process of the underside protective seam in a similar model experiment. The change law of the expansion of the protected coal seam is obtained and the fitting surfaces among the dip angle and strip width of the coal seam with the protection distance and pressure relief angle along the strike and dip of the protected coal seam are established according to the numerical simulation results of underside protective seam mining. It is concluded that the best pressure relief effect can be achieved when the dip angle is 16.7° and the strip width is 70 m. According to the stability threshold of coal pillars considered in strip mining theory, the coal pillar width is calculated to be 50 m. Similarity model experiments and numerical simulations of protected coal seam mining verify the pressure relief effect of the designed protective seam strip width and pillar width. A calculation method of the protective seam strip width, position and pillar width required by the specific width of the protected seam is proposed.

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Section: Coal Seam #2 Mining After the Double Strip Mining In The Undmentioning

confidence: 99%

The pressure relief protection effect of different strip widths, dip angles and pillar widths of an underside protective seam

et al. 2021

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“…The strength equation is applicable to slender pillars. For evaluation of long-term stability of Indian coal pillars, Sheorey et al (1986) generalized the Salamon and Munro (1967) equation as where k has to be evaluated by testing of specimens of size 30 cm. Obert and Duvall (1967) developed empirical relation for the compressive strength of specimens having height-todiameter (or width) ratio as 0.25 to 4.0.…”

Section: Pillar Strength Equation By Salamon and Munromentioning

confidence: 99%

Chronological development in coal pillar design for bord and pillar workings: A critical appraisal

Jawed¹,

Sinha²,

Sengupta³

2013

J. Geol. Min. Res.

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In this study, proper design of coal pillar has ever remained a difficult and challenging task because of two conflicting objectives, namely the conservation of coal on one hand that requires coal pillars to be of minimum size and stability of pillars, and on the other hand that ensures safety of working. The complex loading conditions, the occurrence of seams in close succession and geological abnormalities present in seams make the design problems of coal even more complex and complicated. An attempt has been made in this paper to enlist and describe briefly factors affecting pillar strength and empirical strength equations/formulae developed by different researchers in different parts around the globe. Further, a comparative study has been made for a given set of geo-mining conditions to know the suitability of these equations in terms of their being either over-estimators or under-estimators.

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“…Another key step is determining the chain pillar strength. Formulae to determine the coal pillar strength have been proposed by various academics via numerical, analytical, and empirical studies . By using the method of maximum likelihood, Munro and Salamon presented an empirical formula of the coal pillar strength.…”

Section: Introductionmentioning

confidence: 99%

Field and numerical investigations of gateroad system failure under an irregular residual coal pillar in close‐distance coal seams

Shang

Ning

et al. 2019

Energy Science & Engineering

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The Gaojialiang Coal Mine in Inner Mongolia in China was used as an example to investigate the process of chain pillar and gateroad failure in the lower coal seam under the effect of an irregular residual coal pillar in the upper close‐distance coal seam. The results indicated that after the longwall face in the lower coal seam retreated through the area under the large irregular residual coal pillar in the upper coal seam, the bearing area of the residual coal pillar decreased and the roof pressure continuously concentrated in the elastic core area of the residual coal pillar. Isolated triangular slab rock was formed above the triangular residual coal pillar, and the weight of the overlying strata was transferred downward through the triangular slab rock. When the chain pillar under the residual coal pillar was destroyed due to loading that exceeded its carrying capacity, the upper triangular slab rock rotated and sank, which resulted in the intensification of the concentrated stress in the solid rib of the gateroad in the lower coal seam. Based on the analysis, it is suggested that in the design of a longwall system, a gateroad under an isolated residual coal pillar in the upper coal seam should be avoided when mining in close‐distance coal seams.

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Pillar strength approaches based on a new failure criterion for coal seams

Cited by 24 publications

References 4 publications

The pressure relief protection effect of different strip widths, dip angles and pillar widths of an underside protective seam

The pressure relief protection effect of different strip widths, dip angles and pillar widths of an underside protective seam

Chronological development in coal pillar design for bord and pillar workings: A critical appraisal

Field and numerical investigations of gateroad system failure under an irregular residual coal pillar in close‐distance coal seams

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