UAVs in mining
Imagine a mine where everyday planning software automatically tasks a fleet of Unmanned Aerial Vehicles (UAVs) – completely autonomously – to collect high-resolution coordinate scans, imagery and other remote sensing of the entire mine. Data from highwalls, stockpiles, waste dumps, tailings dams, blasting, and plants is collected by the same software and converted into information for quicker, smarter decision making.
This scenario describes a future that will soon be reality. UAVs are already having a profound effect on mining. The regulatory process is catching up with the technology. According to the ADS report UAV Drones Market-Global Forecast to 2022, by 2022, the international UAV market is expected to be worth 19.73 billion Euros, growing at a rate of about 20 per cent annually.
“There have long been many places in a mine where foot traffic is not allowed or is ill-advised,” said Bryan Baker, Leica Geosystems Unmanned Aerial Systems Sales Manager. “These include near the crests and toes of highwalls, under operating machinery, on stockpiles and muck piles, and near blasts."
“Under these circumstances, obtaining measurements with a surveying rod, total station or GNSS is problematic. UAV aerial photography and remote sensing allow us to capture all that information without putting someone in harm’s way. People, utilities, equipment, and public airspace, however, must be protected from UAVs, with the trade-off being strict safety regulations and serious pilot training.
“That trade-off and the amount of data that can be acquired through UAV technology make it more than justifiable and more than worthwhile.”
Hexagon is among the companies making progress in the application of UAVs in mining. Better blast optimisation, improved safety, faster surveying, and construction of the most comprehensive and continuous project datasets are just some of the advantages of this technology.
“Aerial photogrammetry has been around for as long as the airplane,” said Baker. “For mining though, a manned aircraft was too expensive and too inconvenient for regular airborne photogrammetry. UAS are a natural fit for mining and the advent of the lithium polymer battery has transformed development of airborne photogrammetry.”
Electric motors now safely discharge at a very high rate to be able to carry small aircraft with a payload such as a camera. This technology allows us to capture data in near real time from areas that would otherwise be inaccessible or unsafe for staff. Whether it’s for blast fragmentation, stockpile volumes, or any other mine-related activity, data can be captured quickly and safely.
UAVS and Geosystems
Hexagon Geosystems business, Aibotix, is at the forefront of pushing photogrammetry’s boundaries with its core product, the Aibot X6. The Aibot X6 is an autonomously flying hexacopter, specifically designed for demanding tasks in surveying, mining and industrial inspection. Equipped with a high level of artificial intelligence, this UAV reaches almost any target and can independently create high resolution images and videos. A unique feature of the Aibot X6 offers the possibility to adapt varying kinds of sensors, such as hyper- and multispectral sensors, infrared and thermal sensors, and sensors for other industry-specific missions.
Surveying of the future is dynamic and flexible. Data captured by the Aibot X6 commercial UAV and the software solutions of Aibotix and Hexagon allow mines to generate orthophotos, 3D models and high-density point clouds with great accuracy.
The flight planning software Aibotix AiProFlight makes it simple to obtain all the parameters essential for proficient photogrammetry. The Aibot's ability to hover and take photos at any angle make it ideally suited to stockpile and muck pile monitoring and analysis, plus rock mass characterisation, and plant, equipment and highwall inspections.
For larger-scale aerial surveys, Aibotix recently added the long-range capabilities of the RF-70 fixed wing UAV. The RF-70 can fly up to one hour at higher speeds, allowing it to survey 2.59 square kilometres (640 acres) per flight. This UAV is more than capable of surveying the entire pit, tailings impoundments, waste dumps, and leach pads.
With all the flight planning and data capture features of the Aibot, the newer RF-70 UAV is a complementary partner to provide mines with the tools they need to quickly and easily map their entire mine. The addition of terrestrial laser scanners completes the surveying picture, inside and out. The digital mine of the future will need all of these remote surveying sensors along with automated control and processing software to create complete digital project models.
Minesight geology and planning software
“Hexagon Mining’s mine planning software, MineSight, is well equipped to handle point clouds,” said Hexagon Mining Applications Engineer Johnny Lyons-Baral. “Its point cloud data type features a high level of detail rendering capability, akin to a gaming rendering. The software is capable of displaying billions of points at a time, averaging out points in the pixels with level detail rendering, saving computer memory while displaying high resolution images."
“MineSight’s Point Cloud Mesher turns large data sets into topographic surfaces, tunnels, drifts and slopes, and any other solids and surfaces available from point clouds. It allows mines to quickly go from field capture to usable data for optimisation. The tool removes errors and noise from the data to ensure clean surfaces are available for downstream processes. The colour point cloud can be displayed over the optimised surface to allow feature extraction and geologic interpretation.”
Blasting and comminution
The crushing and grinding of ores account for a significant portion of energy costs at any mine. Comminution is estimated to represent 2 per cent of the world’s electrical power consumption, according to the United States Department of Energy. Consequently, blast fragmentation has an important downstream effect with implications for total comminution energy, as well as extraction, recovery and ultimately profit. Mills need efficient grinding for proper processing. Efficient crushing requires well-blasted material. Poor blast fragmentation of ore material can wipe millions of dollars from the value of a mine.
Aerial photogrammetry and point cloud technology have an important role to play in improving blast optimisation. Open face surveys can be used to detect areas of critical minimum burden that could cause dangerous flyrock. Analysis of the face geology can be used for rock mass characterisation, including initial block size distributions.
Videos taken by UAVs from a safe, eagle-eye perspective are fast becoming popular to evaluate the success of blasts. After blasting, UAV data can reveal blast material movement, delineations between ore and waste, and allow fragmentation analysis. All of this allows mines to quickly learn more about their geology and their blasting performance, driving the site toward better knowledge of its material and better blasting practices.
Geology and geotech
From a geological and a geotechnical perspective, there are numerous opportunities to extract mineralogical and lithological data, as well as structural and geomorphological data, shapes, etc. There are also numerous possibilities for automation to be introduced to the UAV point cloud loop. More interpretation, more usable data for analysis for future designs, and reconciliation are among those possibilities.
“One post-blast scenario could be having the programme automatically delineate a polygon for ore location, waste location, or at least best-guess based on the imagery,” said Lyons-Baral. “Hyper-spectral imagery could also be undertaken where spectral signatures are established for different rock types that have been previously coded.”
A future look
In the future, UAVs will be able to fly longer, farther, carry heavier sensors, and different types of sensors. A fleet of aircraft - multirotor, fixed-wing, or more likely a combination of the two - will be autonomously dispatched each day from mine planning software to collect necessary data before landing and downloading that data onto the cloud and into the office for extraction, analysis, rapid decision making and optimisation.
A version of this story first appeared in World Coal.