Modeling the effects of longwall mining on the ground water system
- Bureau of Mines, Pittsburgh, PA (United States)
- Pennsylvania State Univ., University Park, PA (United States)
The objective of this US Bureau of Mines hydrologic/investigation was to evaluate ground water regime the effects subsidence of longwall mining on the local that were used through field monitoring and numerical modelling. 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 field site. 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.
- OSTI ID:
- 588754
- Report Number(s):
- CONF-9605286--
- Country of Publication:
- United States
- Language:
- English
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