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Mining Publication: Behavior of Simulated Longwall Gob Material
Keywords: Gobs Longwall mining U.S. Bureau of Mines
Original creation date: January 1993
Authors: DM Pappas, C Mark
Report of Investigations - January 1993
Download PDF Document (5.08 MB)
NIOSHTIC2 Number: 20022667
U.S. Department of the Interior, Bureau of Mines, Report of Investigations 9458, 1993 Jan:1-39
This report presents results of a U.S. Bureau of Mines study of longwall gob material. The objective of this work was to determine material stiffness properties of the gob for use in numerical models of rock mass response to longwall mining. Photographs of actual mine gob were digitized to obtain approximate particle size gradations of gob material. The gradation curve was shifted down to a laboratory scale, and 20 uniaxial compression tests were conducted. Varying the maximum particle size was not found to affect the stress-strain behavior, but changing the gradation appeared to influence the stress-strain behavior. The stress-strain relationship of the simulated gob material was nonlinear, the stress-secant-modulus relationship was approximately linear, and the stress-tangent-modulus relationship was approximately a second-order polynomial function. Equations were generated from these curves, providing numerical modelers with a means to estimate gob moduli based on the stress level. In addition, the experimental data were statistically evaluated using multiple regression analyses, producing a series of equations to predict the scant and tangent moduli from the given stress level, bulking factor, rock strength, and thickness-to-width shape ratio of the particles.
Image of publication Behavior of Simulated Longwall Gob MaterialReport of Investigations - January 1993
Download PDF Document (5.08 MB)
NIOSHTIC2 Number: 20022667
U.S. Department of the Interior, Bureau of Mines, Report of Investigations 9458, 1993 Jan:1-39
See Also
Computational Fluid Dynamics Modeling for Underground Mines
Effect of a Surface Borehole on Longwall Gob Degasification (Pocahontas No. 3 Coalbed)
Examination of Design and Operation Practices for Longwall Shields
Longwall Gob Degasification With Surface Ventilation Boreholes Above the Lower Kittanning Coalbed
A Methodology for Determining Gob Permeability Distributions and its Application to Reservoir Modeling of Coal Mine Longwalls
Prediction of Porosity and Permeability of Caved Zone in Longwall Gobs
Probabilistic Modeling Using Bivariate Normal Distributions for Identification of Flow and Displacement Intervals in Longwall Overburden
Technology News 430 - Translucent Face Partition Reduces Longwall Worker's Dust Exposure
Technology News 448 - Improving the Performance of Longwall Gob Gas Ventholes
Underground Gob Gas Drainage During Longwall Mining
Page last reviewed: September 21, 2012
Page last updated: September 21, 2012
Content source: National Institute for Occupational Safety and Health, Mining Program
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