Mining projects in Australia are required to estimate the volume of groundwater extracted from the ground via mine inflow and dewatering operations. They are also required to estimate the source of those inflows, for extraction licencing and to detect potential environmental impacts. The licensed groundwater sources can be generally classified as either alluvial or hard rock.
Estimating the source of inflow for a single open cut mine is a relatively simple numerical modelling exercise. However, when multiple mining operations and multiple sources interact, the estimation of inflow sources can be complex.
A simple ‘sandbox’ numerical groundwater model was used to explore different methods to estimate the source of inflows in a case with multiple mines and groundwater sources. Results of this simple model unveil possible pitfalls if the calculation is not made correctly and suggests a “best approach” for the calculation.