In connection to coal-mining in Svalbard, Norwegian Arctic, coal layers are taken out from rock tunnels underneath glaciers. In periods water has penetrated down to the subglacial areas and partly caused large inflow of meltwater through bedrock fractures into the mining tunnels. In this context water balance studies, melt models and studies of subglacial drainage pattern have been used to explain and predict inflow of water to the coal mines from the glacier above.  A degree-day/radiation melt model was used to predict surface melt-rate and thus water influx. This is necessary input data, but is not able to predict the inflow of water in the tunnels beneath the glacier. In periods much more water has drained into the tunnels beneath the glacier than expected from the calculated melt at the glacier surface. The magnitude of this water input to the tunnels increased with the enlargement of the mine.  It seems that the mining activity enhances the conductivity of the substrate between the glacier bed and the mine. The distribution of hydraulic potential enables lateral influx of water along the glacier bed, thereby increasing the catchment area that drains toward the mine.  The topography of the bed beneath the glacier has also a large impact on the fracturing in the rocks and thus also on the hydraulic potential.