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Mining Publication: A Methodology for Determining Gob Permeability Distributions and its Application to Reservoir Modeling of Coal Mine Longwalls
Keywords: Gobs Longwall mining Methane Modeling
This page is archived for historical purposes and is no longer being maintained or updated.
Original creation date: February 2007
Authors: GS Esterhuizen, C� Karacan
Conference Paper - February 2007
Download PDF Document (0.68 MB)
NIOSHTIC2 Number: 20031652
2007 SME Annual Meeting and Exhibit, February 25-28, Denver, Colorado, preprint 07-78. Littleton, CO: Society for Mining, Metallurgy, and Exploration, Inc., 2007 Feb; :1-6
Methane can be a significant hazard in coal mine longwalling operations and extensive methane mitigation techniques are employed by coal mine operators. Reservoir modeling techniques are used to better understand the liberation and migration of methane from the surrounding rocks towards the mine ventilation system. The caved rock behind the advancing longwall face, known as the gob, can contain high void ratios, providing high permeability flow paths to the methane. The gob is progressively compacted by the weight of the overburden, resulting in a reduction in the void ratio and associated permeability. Estimating the permeability distribution within the gob poses challenges due to its complexity. The authors have developed a new methodology to determine both horizontal and vertical variations in the permeability of the gob. Variations of the permeability in the vertical direction are based on a model of caving and block rotation, which considers the effect of block dimensions and fall height on the void ratio. Gob compaction by the overburden and associated permeability changes are determined from a three-dimensional geomechanical model which simulates the gob as a strain hardening granular material. The resulting three-dimensional permeability distribution in the gob is then transferred to a reservoir model. The paper demonstrates the application of the method and shows that reasonable results are obtained when compared to empirical experience and measurements.
Image of publication A Methodology for Determining Gob Permeability Distributions and its Application to Reservoir Modeling of Coal Mine LongwallsConference Paper - February 2007
Download PDF Document (0.68 MB)
NIOSHTIC2 Number: 20031652
2007 SME Annual Meeting and Exhibit, February 25-28, Denver, Colorado, preprint 07-78. Littleton, CO: Society for Mining, Metallurgy, and Exploration, Inc., 2007 Feb; :1-6
See Also
A CART Technique to Adjust Production from Longwall Coal Operations under Ventilation Constraints
Computational Fluid Dynamics Modeling for Underground Mines
Degasification System Selection for U.S. Longwall Mines Using an Expert Classification System
Effect of a Surface Borehole on Longwall Gob Degasification (Pocahontas No. 3 Coalbed)
Longwall Gob Degasification With Surface Ventilation Boreholes Above the Lower Kittanning Coalbed
Probabilistic Modeling Using Bivariate Normal Distributions for Identification of Flow and Displacement Intervals in Longwall Overburden
Reservoir Engineering Considerations for Coal Seam Degasification and Methane Control in Underground Mines
Reservoir Simulation-Based Modeling for Characterizing Longwall Methane Emissions and Gob Gas Venthole Production
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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