Digging for fire

Engineers at Oviedo University in Spain are devising a method to convert mine shafts into geothermal boilers that will provide energy for local towns.

The method uses mathematical calculations combined with studies carried out in an operating mine to determine how much heat the tunnel can provide.

Rafael Rodríguez, from the Oviedo Higher Technical School of Mining Engineering, said: ‘When the mine is still active one can access the tunnels easily in order to gather data about ventilation and the properties of the rocks, as well as to take samples, design better circuits, and even programme the closure of some sections in order to use them for geothermal energy production.’

The researchers are currently investigating geothermal exploitation of a 2km-long mine shaft, where the temperature of the rocks 500m below the surface can reach 30ºC.

Once their calculations are complete the team plan to obtain the heat for the boilers from the earth’s heat, using water pumped through tubes into the mine at 7ºC and heated to 12ºC. According to Rodríguez, this is a big enough gain to be of benefit to local homes above the mines.

If the research is successful, the group hope that the use of geothermal boilers will provide predictable energy and eliminate the risk of heat contamination to the aquifers while reducing CO2 emissions in the local community.