Evaluation of groundwater flow into mined panels

The impact of underground mining on groundwater flow around a mined panel is quantified. A model is structured to represent strata deformation and concurrent steady fluid flow in a naturally fractured medium as a result of underground mining. The model conceptually represents mechanisms of hydraulic conductivity enhancement caused by deformation through use of a modulus reduction ratio R_m. The modulus reduction ratio R_m is incorporated in the expression for hydraulic conductivity to account for the influence of joint aperture and spacing, joint stiffness and modulus of the intact rock, on changes in hydraulic conductivity. The resulting relations for hydraulic conductivity avoid the requirement of independently determining joint stiffness, as apparent in previous formulations. Panel inflows are defined for a variety of possible geometric and mechanical configurations. Flux charts are developed for straightforward practical use. The resulting charts are verified using two case studies. These reveal that changes in strata conductivities are strongly related to deformations induced by underground mining. Excellent agreement has been achieved.