UAV = Unmanned Aerial Vehicle – generally called Drones by most people nowadays. Drones are becoming an extremely useful tool for mining surveyors. They provide a rapid method of mapping relatively large areas of open pit mines or quarries. Usually using cameras on the lighterweight drones, which after taking hundreds of overlapping photos are automatically converted to a detailed DTM ( digital terrain model ).
There are some important factors to consider when you look beyond the ‘hype’ and excitement of drones, and need to think about the practical and professional aspects of using drones for serious surveying.
Accuracy – a general rule of thumb is that the vertical accuracy is often about twice that of the image pixel size. So the better the quality camera you have the better the accuracy.
Survey control – accuracy is also improved by having photo control points pre-prepared on the ground and visible in the imagery to help rectify the photos during the photogrammetric process. Survey control / photo points are also essential in order to get the DTM final map product in to the correct coordinate system and to be accurately heighted and levelled.
Foliage – Imagery based drone surveys cannot ‘see’ through foliage, but it is now possible to add a small Lidar instrument to a medium sized drone which due to having ‘multiple returns’ of it’s laser beam enables the mapping of the ground beneath trees and other foliage. This stretches the drone’s capability beyond the confines of the bare rock faces of the open pit to include surrounding terrain for drainage studies, future expansion land, new access routes, overland conveyor routes and more.
Software – Most of the attention is placed on the hardware – the flying part – but equally important is to have the right software and processing methods to ensure high and provable quality and to have inputs that work for your mine digital management systems.
Size matters – We are often asked to provide a ‘drone survey’ of vast mining prospect areas. The use of drones is rarely permitted BVLOS – beyond visual line of sight, for safety reasons and so UAV / drone survey work is not appropriate or cost effective for very large areas. We can provide full size fixed wing aircraft based aerial lidar surveys almost anywhere in the World. Please refer www.lidar.co.uk
Consultancy – Whilst we hope you will commission us to come provide regular drone based surveys of your mine / quarry we recognise that many mines will want to buy their own system.
Fixed wing UAV / Drone using photogrammetry for
mapping of open pit mining operations (Wingtra equipment).
This is a fixed wing / VTOL hybrid – vertical take off and landing
Mini lidar instrument from Routescene mounted
on rotary wing – helicopter style of UAV