Unmanned aerial vehicles (UAVs) – commonly referred to as drones – are widely used in many industries for mapping and inspection tasks. Being fairly conservative when it comes to the adoption of new technologies, and also working within a strict regulatory environment, the mining industry has been a little slower in embracing this technology; but it’s certainly catching up of late. Today you can find drones being used for an array of mining activities – and not just aboveground; they are being put to work underground too. Popular applications include the obvious mapping and planning for blasting tasks, but they are also increasingly being used for mine management – tracking vehicles and machines, for instance – and in exploration activities. Here, we look at some of the leading players in this sector to discover the latest technological advances in the use of drones at mines.
Swiss engineering
One of the big names in this sector is the Swiss drone-maker senseFly, now owned by the Parrot group. Seeing great potential for the use of drones in mapping at mines, the company has joined forces with Maptek, an expert in precision measurement and visualisation tools for the mining sector. The partnership means that Maptek can offer its mining customers a full, end-to-end data collection and analysis solution.
Under the terms of the agreement, Maptek can provide its customers with senseFly’s professional mapping and inspection drones (eBee, eBee RTK and albris) alongside its popular I-Site Studio 3D modelling software. “By combining a senseFly UAV with our I-Site Studio 3D modelling software, customers in the mining industry now have a powerful solution that is driven by not only survey requirements, but also the in-depth modelling, change detection and data output requirements demanded by mining professionals,” says Todd Packebush from Maptek.
“senseFly’s durable, largely automated mapping drones are already employed by thousands of professionals, such as mining engineers, around the world, who appreciate the productivity and safety boosting benefits of collecting geospatial data from the air,” adds Jean-Christophe Zufferey, senseFly’s CEO
As well as partnering with other solutions providers, sensFly reports that its drones are also doing some interesting mining work all by themselves. In a recent project, when Energizer Resources needed to survey its site at a large graphite mine in Madagascar, its team purchased two senseFly drones to avoid the expense
of airborne lidar.
A full land survey of the site was required, the results of which would be used to create a 3D contour map of the site. The team would then use this to determine the location of the mine’s dam – since such mines are highly dependent on water – plus the location of its accompanying pipeline, as well as the positions of plant assets such as buildings and equipment.
“For this survey we considered various approaches with DRA,” explains Eric Steffler, the geomatics manager at Energizer Resources. “We looked at flying a large-scale lidar survey for example, using manned aircraft, which would have enabled us to produce a full hydrological model of the region, covering 3,000km2. However, this would have been very expensive – involving the importing of aircraft from South Africa – running to hundreds of thousands of dollars.”
Luckily, DRA discovered that another organisation had already flown some of the area in question and was happy to share its data. With access to this information, Energizer and DRA were able to narrow down the target region to a much more manageable 150km2. But that still left the question of how to survey this land.
“We chose to employ drones for two reasons,” Steffler says: “One was the price. This was very low compared to a lidar survey, which would have cost hundreds of thousands of dollars, even with our reduced survey area. The second was that by making a capital investment in two eBee drones, we could then fly these over our other properties in Canada. Since we now have the technology we need to produce digital elevation models and air photos ourselves, we don’t have to hire third-party companies to do this for us.”
The eBees were kept very busy, with the 150km2 total coverage easily at the larger end of UAV mapping projects. Steffler calculated his UAVs would need to complete over 300 flights in total, with an average flight time of 35 minutes, an average flight coverage of 2.5km2, and capturing some 150 RGB images per flight (15,000 photos in total).
Energizer’s three staff spent a total of 90 days in the field, setting GCPs and flying the drones. Meanwhile Steffler managed the data processing himself, spending up to 12 hours per day on this task – over 120 days in total.
The final data products Steffler and his team produced achieved a GSD of 9.75cm, and accuracy within DRA’s requested +/- 20cm range. The mean re-projection error was 0.179 pixels.
Having successfully completed the Molo’s UAV survey, and used its outputs to inform DRA’s feasibility study, Steffler is now effusive in his praise of drone technology. “The return on our investment has been amazing. We saved ourselves hundreds of thousands of dollars by using the drones in place of airborne lidar, plus we have sub-contracted our UAVs and personnel on several other jobs.”
Blasting off
Going beyond mapping applications, drones are also being used to advance blast design and quality. A leading player here is South African firm BME, which recently established a High-Tech Services unit to advance the application of drones in mine blasting activities.
According to BME technical director Tony Rorke, drones fitted with high-resolution cameras and guided by computer systems using GPS survey data have proved invaluable in improving blast quality. “Our team applies a range of modern technologies such as drones to help us plan, monitor and execute blasts in ways that optimise our clients’ results. The downstream impact can be felt in a range of benefits to mining productivity – such as finer fragmentation, higher digging rates and reduced power consumption in mine crusher circuits.”
Although great strides have been made in surveying and drilling blast-holes, Rorke says that a mine’s survey plan is often not completely accurate or up-to-date – potentially reducing blast quality. “Using drones, we can generate high-quality aerial imagery of the blast site after holes have been drilled, capturing the exact GPS coordinates of each hole. The position of each hole is surveyed and then marked so that it is easily identified in the footage from the drone as it passes overhead.”
The actual blast-hole positions can then be referenced exactly to the survey coordinates of the mine – to allow accurate measurement of the variables necessary to plan an optimal blast.
“The coordinates are exported into our blast timing design program, BlastMap III, and into our Axxis electronic detonator system – so that the appropriate firing sequences, timing and charge distributions can be applied to the blast, based on the exact positioning of each hole,” Rorke explains.
Rorke emphasises the benefits in being able to adjust the timing of a detonation in a blast-hole – as well as firing sequences and charge distribution – to take account of any slight divergence of a hole’s actual position compared with its place on the survey plan. “Unless we measure, we are only guessing; so better measurement – both before, during and after a blast – is the key to optimising blast results. Drones advance our measuring ability greatly when combined our other innovative in-house tools such as our blast planning software together with our electronic detonator system.”
The versatility of a drone as a vehicle for the camera also extends to valuable monitoring functions during and after the blast. What experts can take from the images and graphics is a clearer understanding of what block faces look like, and whether there is any damage or potential problems resulting from the drilling.
“Sampling, measuring and quantifying the fragmentation achieved by a blast is much easier when done from an aerial scale image that a drone can deliver, making the analysis much more useful in improving future blasts,” says Rorke. “The distribution and volumes of fragment sizes are important to monitor, as these are vital to continuous improvement strategies.”
After a blast, drone images from above give a much clearer picture of where coarser and finer fragments are lying – and in what relative quantities. “It may even be possible to use the images as a basis for actually measuring fragment size in a more scientific way,” he says. “We currently take post-blast photographs but it is difficult to interpret these in a way that is statistically valid.”
Software now also allows the creation of a three-dimensional surface of the blast block, by combining the aerial drone imagery and the face profile footage from land-based cameras.
Drones and the digital mine
One of the big names in mining, Hexagon, recognised the potential of drones early on and stated its objective to become a leader in this area. It is applying UAVs to solve several challenges in the industry: better blast optimisation; improved safety; faster surveying; and construction of the most comprehensive and continuous project datasets. In 2014 it bought the unmanned aircraft system (UAS) company Aibotix.
Aibotix’s core product is the Aibot X6, an autonomously flying hexacopter, specifically designed for demanding tasks in surveying, mining, and industrial inspection. Equipped with a high level of artificial intelligence, the UAV reaches almost any target and can independently create high-resolution images and videos. It offers the ability to adapt varying kinds of sensors, such as hyper- and multispectral sensors, infrared and thermal sensors and sensors for other industry-specific missions.
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 Aibot’s ability to hover and take photos at any angle means it is ideally suited to stockpile and muck pile monitoring and analysis, plus rock mass characterisation, and plant, equipment and highwall inspections.
Norwegian firm Asker Oppmaling tested the survey UAV Aibot X6 at 33-ha stone quarry near Oslo. Asker compared the ground control points that were measured conventionally with those measured using the Aibot X6. The result: the values measured using the hexacopter are extremely precise.
The intelligent flying robot also makes the work of surveyors a lot easier and saves a huge amount of time, according to Magnus Myhre, general manager of Asker Oppmaling. “It’s crazy how much time we save by using the multicopter. We can control the Aibot X6 hexacopter from a central location, which saves us the laborious task of having to walk through the pit.”
It would usually take three to four weeks just to survey the Norwegian quarry using conventional methods, which require the surveyors to walk through the quarry to collect the data. Certain parts, such as dangerous pits and muddy areas, are very difficult for them to access and usually cannot be surveyed.
Mining pioneer
An early leader in drones for mining was French company Redbird, which was acquired by US drones solution provider Airware in 2016. Redbird pioneered the use of drone data analytics for mining, quarrying and construction.
Together, Airware and Redbird provide a complete offering for mines and quarries to help digitise and optimise operations.
Airware is also working with Luck Stone, the construction aggregate division of Luck Companies. As an early adopter of UAV technology, Luck Stone now owns a small fleet of UAVs that are deployed several times a week to collect data at many of the company’s 22 operations in Virginia and North Carolina, USA. Another corporate investment in this fast-evolving field of expertise was dedicating an associate to be a full-time licensed UAV pilot.
“We recognised the need to acquire greater amounts of accurate, repeatable data from the air that could be easily accessed and analysed for improved operational efficiency,” says John Blackmore, survey and mapping supervisor at Luck Stone.
“UAV technology is changing rapidly, so we began talking with Airware and evaluating all of the drone solutions on the market,” he explains. “We were very impressed with Airware’s advanced, end-to-end UAV data collection processes and powerful analytics tools that were developed specifically for the mining and aggregate industry, which led to this exciting partnership.”
While flying above the Luck Stone operations, UAVs take hundreds of aerial photos that will be uploaded to Airware’s cloud-based platform. The business intelligence resulting from those images will be used for a wide variety of decision-making purposes to include volumetric measurements, safety inspections, and pit efficiency analytics.
