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Mining Publication: Probabilistic Modeling Using Bivariate Normal Distributions for Identification of Flow and Displacement Intervals in Longwall Overburden
Keywords: Gas emissions Gobs Longwall mining Methane
Original creation date: January 2011
Authors: C� Karacan, GV Goodman
Peer Reviewed Journal Article - January 2011
Download PDF Document (1.02 MB)
NIOSHTIC2 Number: 20038269
Int J Rock Mech Min Sci 2011 Jan; 48(1):27-41
Gob gas ventholes (GGV) are used to control methane emissions in longwall mines by capturing it within the overlying fractured strata before it enters the work environment. In order for GGVs to effectively capture more methane and less mine air, the length of the slotted sections and their proximity to top of the coal bed should be designed based on the potential gas sources and their locations, as well as the displacements in the overburden that will create potential flow paths for the gas. In this paper, an approach to determine the conditional probabilities of depth-displacement, depth-flow percentage, depth-formation and depth-gas content of the formations was developed using bivariate normal distributions. The flow percentage, displacement and formation data as a function of distance from coal bed used in this study were obtained from a series of borehole experiments contracted by the former US Bureau of Mines as part of a research project. Each of these parameters was tested for normality and was modeled using bivariate normal distributions to determine all tail probabilities. In addition, the probability of coal bed gas content as a function of depth was determined using the same techniques. The tail probabilities at various depths were used to calculate conditional probabilities for each of the parameters. The conditional probabilities predicted for various values of the critical parameters can be used with the measurements of flow and methane percentage at gob gas ventholes to optimize their performance.
Image of publication Probabilistic Modeling Using Bivariate Normal Distributions for Identification of Flow and Displacement Intervals in Longwall OverburdenPeer Reviewed Journal Article - January 2011
Download PDF Document (1.02 MB)
NIOSHTIC2 Number: 20038269
Int J Rock Mech Min Sci 2011 Jan; 48(1):27-41
See Also
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
Methane Emission Rate Studies in a Central Pennsylvania Mine
A Methodology for Determining Gob Permeability Distributions and its Application to Reservoir Modeling of Coal Mine Longwalls
Modeling and Prediction of Ventilation Methane Emissions of U.S. Longwall Mines Using Supervised Artificial Neural Networks
A New Methane Control and Prediction Software Suite for Longwall Mines
Numerical Analysis of the Impact of Longwall Panel Width on Methane Emissions and Performance of Gob Gas Ventholes
Technology News 448 - Improving the Performance of Longwall Gob Gas Ventholes
Technology News 465 - Method for Predicting Methane Emissions on Extended Longwall Faces
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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