Important information regarding an upcoming aerial survey [SURVEY NOW COMPLETE]
In early 2023 Deep Digital Cornwall are carrying out an airborne electromagnetic (AEM) survey over two areas in Cornwall. Please find more information relating to this below. If you are based in close proximity to the survey area you may have received a flyer that was circulated to give local communities and businesses notice.
Survey Window Has Begun
The helicopter requires winds below 25knots, no rain and a high cloud ceiling (good visibility) to fly.
Daily updates below
06/03/23: The team plan to survey the remaining areas in the western portion of United Downs.
03/03/23: KELLY BRAY AREA NOW COMPLETE. The team will resurvey some parts of the United Downs block due to the fault noted 01/03/2023.
02/03/23: The team plan to complete the Kelly Bray/Callington block.
01/03/23: The team will be flying two remaining lines over the United Downs area this morning then look to move onto the Kelly Bray /Kit Hill area. Please note, unfortunately some of the lines over United Downs may need to be returned to as NRG have noted a fault had existed with the sensor causing some data anomalies.
28/02/23: The team will be flying the United Downs area today (wind may cause a pause), surveying the remaining eastern portion of the block in green (map below) and then flying a handful of east-west lines over the area (also green).
27/02/23: The team will attempt to complete flying the United Downs area today (wind may cause a pause), surveying the remaining eastern portion of the block in green and then flying a handful of east-west lines over the area (also green).
27/02/23: Survey paused due to high winds.
26/02/23: The team will fly the remaining eastern section (N-S) of the United Downs block and fly some (E-W) lines filling the block. There is a chance they will begin surveying the Redmoor/Kelly Bray block if weather permits.
25/02/23: The team have completed the western portion of United Downs. Plan to survey the yellow area – 80% likelihood due to weather.
23/02/23 and 24/02/23: The team will continue surveying the orange area but wind and low-clouds will need close monitoring. Area completed.
22/02/23: The team hope to continue surveying the orange area but will closely monitor wind levels.
21/02/23: Test flights are expected in the morning and the team plan to begin surveying the orange area in the below map in the afternoon.
20/02/23: Survey is on hold due to hampering weather conditions, test flights are expected in the afternoon.
19/02/23 and 20/02/23: The team will begin surveying the western portion of the United Downs block shown in orange on the map.
17/02/23 and 18/02/23: High winds and poor visibility have led to a delay in starting the survey. Unlikely to begin until Sunday.
16/02/23: Today the team will be completing testing and the first production flight is expected tomorrow over United Downs.
What is DDC?
Deep Digital Cornwall (DDC) is a research project led by the Camborne School of Mines and the Institute for Data Science and Artificial Intelligence at the University of Exeter. DDC is funded by the European Regional Development Fund (ERDF), via HM Ministry of Housing, Communities, and Local Government (HMCLG). Delivery partners include Cornish Lithium, Cornwall Resources and the South West Centre of Excellence in Satellite Applications.
The aim of the Deep Digital project is to create a world-leading cluster of research-active, highly innovative businesses applying digital solutions to a wide range of business opportunities connected to the underground including mining, geothermal, civil engineering, environmental, surveying, water resources, planning and permitting, heritage, tourism.
What's this survey?
In early 2023, DDC and their delivery partners are contracting an airborne electromagnetic (AEM) survey over two areas comprising approximately 100km2 in total. The survey will utilise recently developed high-resolution AEM instrumentation and will be complimentary to earlier geophysical surveys in the area. The survey data will be made openly available to all interested parties, including industry and academia, through DDC’s 3D visualisation suite.
The depth of investigation of the survey will depend on the geology particularly as the survey covers both granite and low-grade meta-sedimentary areas but on average the survey is expected to reach about 400m.
How is the survey going to be undertaken?
The survey will be undertaken by a helicopter flying at a safe height authorised by the Civil Aviation Authority. Over rural areas this is 80 m (about eight times the height of a two-storey house). Over urban areas this height is 240 m. The helicopter will be towing a sensor, which is like a large, sophisticated metal detector. This measures the natural electrical conductivity of the surface and subsurface of the Earth, and the composition of soil, rocks and water in the subsurface can be interpreted based on these measured physical properties.
Where will the survey be?
Please refer to the interactive map towards the top of this web page to see the two survey areas in United Downs and Redmoor as well as the location of the DDC Hub.
Who is flying the survey?
The survey will be operated by New Resolution Geophysics (NRG), an airborne survey company based in Cape Town, South Africa. This is using NRG’s Xcite™ airborne electromagnetic (AEM) system.
Why do we need this survey?
The survey is intended to improve understanding of regional geology by mapping the surface of the granite, the regional fault systems, and any associated mineralisation. Airborne surveying is the most rapid and cost-effective means of acquiring large-scale geophysical data for supporting geological mapping, mineral exploration, risk mapping and geothermal energy exploration.
Given the UK government’s current focus on critical minerals, it is also hoped that the survey will represent the first phase of a regional geophysical survey, as part of creating a credible geoscientific baseline to facilitate world-class mineral exploration by the private sector.
When exactly will the survey happen?
The exact timing of the survey is weather dependent due to the nature of the survey which will involve equipment tethered from a helicopter.
Winter weather in Cornwall is frequently stormy so a weather window will be observed. For keeping up to date on exact timings for the survey please check back here. [Or join our Telegram channel and follow the Deep Digital Cornwall Twitter Feed.]
How can I access the survey data once available?
Once the survey has been flown and the data has been processed, Deep Digital Cornwall will be loading the data into their 4D visualisation suite located on Penryn Campus. Data will also be downloadable by accessing the Digital Assets Catalogue and contacting us to let us know what files you would like to be transferred, at which point a Wetransfer or other file sharing site will be utilised.
Queries should be directed to Cornish Lithium firstname.lastname@example.org
Airborne electromagnetic geophysics is useful for imaging resistive features (granite) and conductive features (mudstones/sulphide mineralisation). It also maps water content as a conductive feature and can be applicable to water resource management. The AEM technique utilises natural variations in electrical conductivity beneath the surface, which results from variation in rock and pore fluid properties. The presence of electrically conductive minerals such as sulphide minerals, graphite and clays, or electrically conductive fluid such as saline groundwater, results in greater conductivity relative to non-conductive mineral assemblages, or non-conductive fluid (such as fresh ground water).
AEM datasets are normally interpreted in conjunction with down-well datasets relevant to conductivity, and other spatial and airborne datasets including surface geology and magnetics and gravity.
AEM works by transmitting an electromagnetic signal (weak low-frequency radio waves) from the sensor attached to the helicopter. This signal induces eddy currents in the ground which are detected by receiver coils towed below and behind the helicopter. Variations in the conductivity of the ground can be detected to a depth of several hundred metres, depending on the geological and hydrogeological stratigraphy and the specific acquisition system used. Complex processing is required to allow for interpretation, and are therefore usually designed to detect particular subsurface targets. By conducting the survey along pre-planned flight paths that follow a “lawn mowing” pattern, complete coverage of an area can be obtained, with the data “slices” then being processed into 3D images.
AEM is safely used throughout the world for a variety of geologic studies and in the evaluation of land features, natural resources including groundwater, and even volcanoes! The electromagnetic signals generated by these types of systems are considerably weaker than other natural and man-made sources such as lightning and the broadcasting of radio stations. Aircraft are flown by specialists who have many decades of experience collecting data in a wide variety of environments and the helicopter stays high enough that there is no rotor wash/downdraft felt on the ground.