The mine-water heat resource in the abandoned metal mines of Cornwall, UK

Cornwall's history as one of the richest metal-mining regions in the world has left a legacy of hundreds of kilometres of abandoned mine workings containing millions of cubic metres of water. Despite the growing development of mine-water heat schemes in former coal-mining areas in the UK, the potential geothermal resource within the flooded mines in Cornwall has yet to be fully recognized. The utilization of this resource presents a few challenges that are different from those met when extracting heat from former coal mines, but it presents readily accessible opportunities for producing sustainable low-carbon heating, cooling and thermal storage. There are recorded to be 154 mines in Cornwall that are over 200 m deep. Recent studies have identified the temperature and volumetric resource that may be available in some of the deep mines, together with examples of four mines that show distinctly different types of hydrogeological systems. This has demonstrated the potential and the importance of thoroughly understanding the hydrodynamics of the shafts and underground workings, and how these can be best utilized as a low-enthalpy heat resource.