Hydrogeological Research

The main source of water penetrating into the mine drifts is the multilayered aquifer composed of five sandy layers belonging to Ravnets Formation. They are bedding at different depth above the exploited coal seams. The thickness of water bearing layers is variable within a wide range - from 0,5m to 10-12m. A complicated hydraulic connection between them exists in faulted and recharge zones. The multilayered aquifer is recharged by precipitation, surface water and thermal water from underlying Upper Cretaceous volcano-sedimentary rocks as well. The highest ground water breaks into the mine during the whole period of exploitation had reached up to 60l/s. Chemical analyses of 46 water samples taken from 18 wells intersecting the multilayered aquifer have been summarized. Depth of wells is varying between 196 to 460 m. Water temperature is changing from 18,5 to 26oC. TDS varies from 0,652 to 1,34g/l and pH - from 7,4 to 8,8. Water is of hydrocarbonate-sodium-magnesium type.