UNEXMIN Georobotics Ltd., as part of the UNEXUP project, conducted exploration dives in March 2022 at the South Crofty mine in Cornwall, located in south-west England. The main objective of the mission was to explore the “195-fathom pumping station,” situated approximately 350 meters below the surface and gather visual information on the shaft section between the water surface and the pumping station. The mine had shut down in the 1990s and since then had flooded. The investigation aimed to assess the feasibility of reopening the mine after de-watering it.
The dive took place in one compartment of the four-compartment shaft using the UX1-NEO robot. The robot captured full-colour images and multibeam sonar data. The water quality was poor, with turbidity, disturbed sediment, and floating particles, leading to limited visibility, usually not exceeding 5 cm. However, the water cleared sufficiently to provide a longer field of view when the team reached the pumping station’s depth, approximately 290 m below water level. The sonar scan confirmed the position and dimensions of a gate blocking access to the pumping station. Despite being unable to access the pumping station due to the gate, the dive confirmed the shaft’s structural integrity to the maximum dive depth of 292 m.
During the mission, the team also measured various water quality parameters, such as temperature, pH, and electrical conductivity, indicating consistent temperatures of 23-24 °C, pH between 8.2 and 8.4, and electrical conductivity around 9040 µS/cm.
See the following YouTube video about the mission: