Geothermal resources of former coal mine Nowa Ruda, Poland

Abstract

The flooded coal mine of Nowa Ruda in south-western Poland is presented as an example. In the Piast mining field the abandoned workings in the Carboniferous Lower Zacler beds contain about 5,000,000 cubic meters of water at a temperature of 16 26?C. The exploitation of the mine water for geothermal heat pumps is planned. Two two-dimensional (2-D) numerical models based on the TOUGH2 program have been developed to introduce heat exchange modeling into this mining field. The model of temperature recovery of abandoned workings shows the time required to return to natural thermal conditions in a rock massif that has cooled down during coal mining. The expected time for temperature recovery is approximately 10 years. The model of a geothermal doublet producing water at a temperature of 23?C from abandoned workings presents the rate of cooling of the reservoir at production rates of 10 l/s (thermal output power ~800 kWt) and 20 l/s (thermal output power ~1600 kWt).