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Mining Publication: Evaluation of the Strength of Slender Pillars
Keywords: Numerical modeling Pillars
This page is archived for historical purposes and is no longer being maintained or updated.
Original creation date: March 2006
Authors: GS Esterhuizen
Peer Reviewed Journal Article - January 2007
Download PDF Document (0.78 MB)
NIOSHTIC2 Number: 20032623
Trans Soc Min Metall Explor 2007 Jan; 320:69-76
Conference Paper - March 2006
Download PDF Document (0.66 MB)
NIOSHTIC2 Number: 20029904
2006 SME Annual Meeting and Exhibit, March 27-29, St. Louis, Missouri, preprint 06-003. Littleton, CO: Society for Mining, Metallurgy, and Exploration, Inc., 2006 Mar; :1-7
Pillars with width-to-height ratios of less than 1.0 are frequently created in underground hard-rock mines. The strength of slender pillars can be estimated using empirically developed equations. However, the equations can provide variable results when the width-to-height ratios approach 0.5. This paper investigates some of the issues affecting pillar strength at low width-to-height ratios in hard, brittle rock. The investigation includes an evaluation of empirical pillar strength data presented in the literature and observations of pillar performance in underground limestone mines in the Eastern United States, supplemented by numerical modeling in which failure processes and sensitivity of slender pillars to variations in rock mass properties are evaluated. The results showed that the strength of slender pillars is more variable than that of wider pillars. The numerical model results demonstrated the increasing role of brittle rock failure in slender pillar strength. The absence of confinement in slender pillars can result in a fully brittle failure process, while wider pillars fail in a combined brittle and shearing mode. The onset of spalling in slender pillars occurs at or near the ultimate strength, while this is not the case for wider pillars. Slender pillars are shown to be more sensitive to the presence of discontinuities than wider pillars, which can partly explain the increased variability of slender pillar strength. Two examples are presented that illustrate failure initiation by brittle spalling and the sensitivity of slender pillars to the presence of discontinuities.
Image of publication Evaluation of the Strength of Slender PillarsPeer Reviewed Journal Article - January 2007
Download PDF Document (0.78 MB)
NIOSHTIC2 Number: 20032623
Trans Soc Min Metall Explor 2007 Jan; 320:69-76
Conference Paper - March 2006
Download PDF Document (0.66 MB)
NIOSHTIC2 Number: 20029904
2006 SME Annual Meeting and Exhibit, March 27-29, St. Louis, Missouri, preprint 06-003. Littleton, CO: Society for Mining, Metallurgy, and Exploration, Inc., 2006 Mar; :1-7
See Also
Coal Bumps and Odd Dynamic Phenomena - A Numerical Investigation
Degasification System Selection for U.S. Longwall Mines Using an Expert Classification System
Effects of Weak Bands on Pillar Stability in Stone Mines: Field Observations and Numerical Model Assessment
Elastic and Shear Moduli of Coal Measure Rocks Derived from Basic Well Logs Using Fractal Statistics and Radial Basis Functions
Evaluation of the Effects of Length on Strength of Slender Pillars in Limestone Mines Using Numerical Modeling
In Situ Stress Measurements Near the Ross Shaft Pillar, Homestake Mine, South Dakota
Investigation of Pillar-Roof Contact Failure in Northern Appalachian Stone Mine Workings
Pillar Stability Issues Based on a Survey of Pillar Performance in Underground Limestone Mines
Proceedings: New Technology for Ground Control in Multiple-seam Mining
Stochastic Modeling of Gob Gas Venthole Production Performances in Active and Completed Longwall Panels of Coal Mines
Page last reviewed: May 3, 2016
Page last updated: May 3, 2016
Content source: National Institute for Occupational Safety and Health, Mining Program
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