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Mining Publication: Development of Numerical Models to Investigate Permeability Changes and Gas Emission around Longwall Mining Panel
Keywords: Gas emissions Longwall mining Longwall panels Numerical modeling
This page is archived for historical purposes and is no longer being maintained or updated.
Original creation date: June 2005
Authors: GS Esterhuizen, C� Karacan
Conference Paper - June 2005
Download PDF Document (0.39 MB)
NIOSHTIC2 Number: 20028124
Proceedings of the 40th U.S. Symposium on Rock Mechanics, Anchorage, AK, June 25-29, 2005. Alexandria, VA: American Rock Mechanics Association, 2005 June; :1-13
Underground longwall mining of coal causes large-scale disturbance of the surrounding rock mass. The disturbance can increase the rock mass permeability through a reduction on the stress, as well as formation of new fractures in the rock. Methane gas contained in the disturbed rock mass can migrate toward the low-pressure mine workings and present an explosion hazard. This paper describes the application of a finite difference program to develop a geomechanical model that predicts permeability changes within the rock mass. The calculated permeabilities are used as input to a reservoir simulator that models methane desorption from the coal matrix, methane release from the rock layers, and flow toward the mine excavations. The model also considers the basic characteristics of the mine ventilation network. The geomechanical model uses empirical relationships between fracture permeability and stress to calculate permeability changes around a longwall face. The extent of rock failure is determined using a strain-softening model that considers both rock matrix and bedding plane failure. The cave rock (gob) is modeled as a compressible, granulated material. The calculated horizontal and vertical permeabilities around the longwall face are averaged and used as one of the inputs to the reservoir model. The reservoir model was developed and calibrated against records of methane flow at a study mine in southwestern Pennsylvania. Good correlation between actual gas production and model outputs has been achieved. The modeling approach provides a basis for estimating methane inflow and optimizing control measures.
Image of publication Development of Numerical Models to Investigate Permeability Changes and Gas Emission around Longwall Mining PanelConference Paper - June 2005
Download PDF Document (0.39 MB)
NIOSHTIC2 Number: 20028124
Proceedings of the 40th U.S. Symposium on Rock Mechanics, Anchorage, AK, June 25-29, 2005. Alexandria, VA: American Rock Mechanics Association, 2005 June; :1-13
See Also
Analysis and Prediction of Longwall Methane Emissions: A Case Study in the Pocahontas No. 3 Coalbed, VA
Degasification System Selection for U.S. Longwall Mines Using an Expert Classification System
Development of Multiple Regression Functions for Performance Prediction of Gob Gas Ventholes for Sealed and Active Longwall Mines
Elastic and Shear Moduli of Coal Measure Rocks Derived from Basic Well Logs Using Fractal Statistics and Radial Basis Functions
Methane Diffusion Parameters for Sized Coal Particles: A Measuring Apparatus and Some Preliminary Results
Modeling and Prediction of Ventilation Methane Emissions of U.S. Longwall Mines Using Supervised Artificial Neural Networks
Numerical Analysis of the Impact of Longwall Panel Width on Methane Emissions and Performance of Gob Gas Ventholes
Probabilistic Modeling Using Bivariate Normal Distributions for Identification of Flow and Displacement Intervals in Longwall Overburden
Stochastic Modeling of Gob Gas Venthole Production Performances in Active and Completed Longwall Panels of Coal Mines
Technology News 465 - Method for Predicting Methane Emissions on Extended Longwall Faces
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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