Determining the influence of longwall mining on groundwater resources

A method is developed to describe the influence of mining on groundwater resources that utilizes induced strains to define the modification of the conductivity field. This methodology is applied to a suite of mining geometries that incorporate the influence of surface topography. Surface topography is illustrated to provide a controlling effect on the development of mining induced strains, and as a consequence, on groundwater resources. Distinct zones of hydraulic influence develop, that coalesce as extraction becomes shallower. For deeper geometries, the hydraulically isolated form of the zones is evaluated using an approach that incorporates the potential for strain localization. The incorporation of localization is shown not to affect the general conclusion that distinct hydraulic zones may develop and remain isolated, providing the problem scale is sufficiently large. Correspondingly, observational rules developed to predict the extent and location of potential aquifer dewatering are confirmed and may be extended to evaluate the potential long term influence of mining on the groundwater system.