Why helicopter towing large circular object has been flying above Cornwall

• Footage of the unusual object being dragged around above Cornwall by helicopter

People across Cornwall might have noticed a helicopter flying through the skies dragging a round flying object over the last few days - and it's back again today.

The unusual sight is part of an electromagnetic survey to help improve the understanding of the region's geology.

The Deep Digital Cornwall project is carrying out the survey near United Downs and Redmoor to map out the geology, natural resources and environment of the county.

The survey is being led by the University of Exeter's Cambourne School of Mines and Institute for Data Science and Artificial Intelligence.

The mapping will cover the granite underground, regional fault systems and the location of mineralisation of potential economic interest.

As part of the survey, a sensor is towed beneath a helicopter to measure the natural electrical conductivity of the Earth's surface and subsurface.

It will fly about 80m above ground, rising to 240m in more built-up areas.

The work could contribute towards the exploration of minerals that contain the technology metals required for the transition to net zero, geothermal energy for the region’s energy mix, and an understanding of hydrogeology and groundwater - which is important to mitigate flooding and coastal erosion.

In total, the survey will cover 100km squared and the new data will complement previous surveys in the area, including the Tellus South West project.

It will be made publicly available for further research via the Deep Digital Cornwall hub and within the Deep Digital Cornwall 4D visualisation suite.

Camborne School of Mines professor Frances Wall said: “It is really exciting to be flying this state-of-the-art geophysics survey.

"Preparations have been underway for some time to make sure everything is ready, including the official clearances and communication with local residents in the areas where the helicopter will fly.

“We are looking forward to seeing the new data and testing how it helps us understand Cornwall’s important underground Geo resources, such as minerals we need for the energy transition and geothermal energy”.

The Deep Digital Cornwall project launched two years ago in early 2021 and is worth £4.4 million.

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