CADS Survey, an Australian supplier of marine, pipeline, and civil surveying services, C.R.Kennedy & Co, a national importer and distributor of surveying equipment in Australia, and the German drone manufacturer Aibotix surveyed one of the world’s largest diamond mines with the Aibot X6 UAV (Unmanned Aerial Vehicle). They successfully executed a so called negative waypoint flight, 100 m below the pilot’s position. The aerial survey of the Argyle mine in Western Australia meant an interesting challenge: Equipped with a high-resolution digital camera, the Aibot X6 did not only have to vertically photograph the flight from an angle, but had to execute a negative waypoint flight as well. This means that it had to follow a route previously planned on a computer, running 100 m below the pilot’s position.

The UAV covered almost 100 ha of the 300 m deep mine and captured high-resolution pictures in eight flights. Each of the flights had a duration of 10 to 15 minutes. The data collected were further processed into an orthophoto, a point cloud and a 3D model, all with a Ground Sample Distance (GSD) of 2 to 6 cm.

Sam Van Eldik, Survey Division Manager for Civil and Aerial at CADS Survey, was impressed by the accuracy of the generated data: “Using the Aibot X6, we are able to generate data of the open-pit mine with an accuracy which would not have been reached with a common airplane.”

CADS Survey will continue to work with the senior surveyor from the owner Rio Tinto at the Argyle mine, using the Aibot X6 UAV to monitor the mine for subsidence, on a monthly basis.

Argyle is located in Western Australia in the rugged East Kimberley region. It is owned and managed by Rio Tinto and consists of an above ground and an underground area. Since the open pit mine cannot be entered below a level of 50 m, aerial surveying is the only possibility to detect subsidence or other potential dangers to the workers underground at an early stage.

Technical Details

• Camera: Nikon Coolpix A
• Sensor resolution: 16.2 Megapixel
• Flight height: -100 m to +150 m
• Image overlap: about 60% – 90%
• Ground Sample Distance (GSD): 2 cm – 6 cm

Data Processing

• Synchronisation of the GPS information with the images shot by Aerial Image Manager for a fast post-processing
• Further processing with photogrammetry software Agisoft PhotoScan.