Mine shafts that are about to be closed down could be transformed into geothermal boilers, taking advantage of the Earth’s internal heat and putting it to use in nearby communities. 

Rafael Rodríguez and María Belarmina Díaz, engineers with the Oviedo Higher Technical School of Mining Engineering in Spain, have developed a method of using mines to provide geothermal energy that would allow them to estimate the amount of heat a tunnel could possibly provide. Their research was published in the journal Renewable Energy.

"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 and design better circuits, and even programme the closure of some sections in order to use them for geothermal energy production", Rodríguez told Science Daily.

The method wouldn’t work with mine shafts that are already closed because it’s no longer possible to gain access to make modifications or gather useful data that would help evaluate and improve the system.

Aside from providing a predictable amount of energy, abandoned mine shafts could function as an open tube system "but without any risk of heat contamination of aquifers".

Using geothermal energy for mines to heat homes and water is highly efficient and environmentally friendly, as it helps reduce greenhouse gas emissions, make use of local resources, doesn’t pollute the environment and doesn’t require a lot of construction and development.