The drilling site is on the United Downs industrial estate, chosen for its geology, existing grid connection, proximity to access roads and limited impact on local communities.
[2] The Camborne School of Mines led Cornish Hot Dry Rocks (HDR) project, undertaken in the 1980s at Rosemanowes Quarry, was designed to test the theory of inducing a fracture network within granite to create a geothermal reservoir.
[2] The geothermal system employed to generate power at United Downs targeted a radiogenic granite batholith that exhibited enhanced permeability due to its intersection with the Porthtowan fault zone.
[16][17][18][19] The Cornubian granite batholith stretches from Dartmoor to the Isles of Scilly and contains a high concentration of heat-producing isotopes such as thorium (Th), uranium (U) and potassium (K).
[21] NNW-SSE striking 'crosscourse' faults, which are often long and show evidence of significant displacement, are aligned parallel to the regional maximum horizontal stress and therefore are believed to be the most ‘open’ structures, providing enhanced permeability.
From an early stage it was established that time, effort and a personal approach were crucial to finding the extent of the community and reaching a diverse range of its members.