Improved Modelling Concept for Dewatering Planning in Velenje Coal Mine

The basis for the safe extraction of mineral resources underground is good knowledge of the local and surrounding geological conditions and the activity of the nearby aquifers. Hydrogeological modelling in combination with dewatering of the aquifers above the coal and monitoring of the groundwater level in piezometers is of particular importance for safe underground coal mining in the Velenje mine. This study shows the contribution of an improved hydrogeological conceptual model to the prediction of groundwater movement in the aquifers above the coal seam using a hydrodynamic six-layer model. The improved hydrogeological conceptual model is based on the determination of the groundwater age and a detailed geological classification of the layers. The groundwater ages, determined using the tritium detection method, were important to understand the recharge of the individual aquifers. As there is no direct recharge at the surface, the aquifers are only recharged by the slow leakage of groundwater from the upper to the lower aquifers. The hydrodynamic six-layer model, which is based on an improved hydrogeological conceptual model, now simulates groundwater more accurately than previous hydrodynamic models and helps with dewatering planning and the technical design of mining facilities near aquifers.