Mining Publication: Modeling the Effects of Longwall Mining on the Ground Water System
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Original creation date: January 1995
The objective of this U.S. Bureau of Mines hydrologic-subsidence investigation was to evaluate the effects of longwall mining on the local ground water regime through field monitoring and numerical modeling. Field data were obtained from multiple-position borehole extensometers (MPBX's) that were used to measure subsurface displacements. Survey monuments were installed to measure mining-induced surface deformations. Numerous drawdown and recovery tests were performed to characterize hydrologic properties of the overburden strata. Coreholes were drilled above the study area to determine lithologic and strength characteristics of the overburden strata using the rock samples collected. Electronic recorders were installed on all monitoring wells to continuously monitor ground water levels in coordination with mining of the longwall panels. A combined finite element model of the deformation of overlying strata, and it's influence on ground water flow was used to define the change in local and regional water budgets. The predicted effects of the postmining ground water system determined by the model correlated well with field data collected from the fieldsite. Without an infiltration rate added to the model, a static decrease of 3.0 m (10 ft) in water level would occur due to mining of both longwall panels and if an infiltration rate was inputted in the model, no predicted long-term effects would occur to the ground water system.
Authors: RJ Matetic, J Liu, D Elsworth
Report of Investigations - January 1995
NIOSHTIC2 Number: 20024641
U.S. Department of the Interior, Bureau of Mines, Report of Investigations 9561, 1995:1-20
See Also
- Coal Mine Subsidence Prediction Using a Boundary-Element Program
- Cross Formational Flow of Water into Coalbed Methane Reservoirs: Controls on Relative Permeability Curve Shape and Production Profile
- Degasification System Selection for U.S. Longwall Mines Using an Expert Classification System
- Development of Numerical Models to Investigate Permeability Changes and Gas Emission around Longwall Mining Panel
- Elastic and Shear Moduli of Coal Measure Rocks Derived from Basic Well Logs Using Fractal Statistics and Radial Basis Functions
- Evaluation of the Impact of Standing Support on Ground Behavior in Longwall Tailgates
- Predicting Methane Emissions from Longer Longwall Faces by Analysis of Emission Contributors
- The State-of-the-Art in Coal Pillar Design
- Subsidence Prediction Using a Laminated, Boundary-Element Program
- Timing and Duration of Subsidence Due to Longwall Mining
- Content source: National Institute for Occupational Safety and Health, Mining Program