Imagination & innovation key to going underground

Increasing mine depth, a naturally hazardous environment, remains one of the key risks faced by mine owners & operators, irrespective if it is a surface or underground mine.

As advances in drone design & sensor development have helped to mitigate risks, improve production & reduce costs across the value chain, the next step or evolution of operating drones in mining has been to do it frequently, & at an acceptable cost underground.

While there have been some well publicized successes of drones being used in certain instances underground, the reality is that the complexity of flying underground safely, has made this a very limited field.

However, while flying underground is complex; it is not just a hardware challenge, but also a software & application development problem. In an environment, where technology & hardware solutions are increasingly capable of operating underground & able to perform tasks, the questions mine owners & drone operators have to consider is what tasks & what applications are the best fit? If we can answer these questions then we can do it frequently & at scale.

But, why is flying underground complex?

Underground environments pose many obstacles to flying drones. Confined spaces, obstacles, continued expansion; reduced visibility; air velocity; dust concentration; & lack of wireless communication systems make it a difficult task for an operator to fly a drone in underground working areas. Furthermore, access to unreachable & dangerous locations in underground mines is often impossible for a drone operator.

To operate underground, the preferred sensors are currently stereo cameras, ultrasonic sensors, laser range finders (LFRs) dual redundant IMUs, & infrared sensors.

Currently, we can identify several potential applications for underground mining operations. These include: Geotechnical Characterization, Rock Size Distribution, Gas Detection, Rescue Missions & the Mapping of Abandoned Mines.

Applications for Drones Underground

Geotechnical characterization

Rock mass data collections in underground openings requires the inspector(s) to survey the rock mass physically. The presence of personnel in unsupported areas such as open stope & newly blasted working faces endangers the safety of mining operators. To analyse the rock mass, imagery techniques such as photogrammetry & FLIR (forward-looking infrared) are used. Photogrammetry has also been proven to provide data for generating geological models, structural data for kinematic (the motion of points, bodies (objects), & systems of bodies (groups of objects) without considering the forces that cause them to move) & numerical analyses. In addition, FLIR imagery can be used to recognize areas of loose rock, which normally remain unnoticed until it becomes a hazard.

Rock Size Distribution Analysis in Underground Mines

The majority of underground hard rock mines use drilling & blasting methods for rock extraction. Assessment of rock size distribution after blasting is an important measurement for the next production phases (i.e., loading & hauling). There are some methods for rock size distribution analysis, including visual observation by an expert, sieve analysis, & image processing. Image analysis methods are fast & relatively accurate for rock fragmentation measurements.

Gas Detection in Underground Coal Mines

By applying a set of sensors to continuously measure atmospheric parameters & gas concentration enables a drone to be used for hazardous gas detection in underground coal mines, which can reliably asses & detect the likelihood of coal fires. However, during tests the flight time was limited to 10-15 minutes due to environmental conditions.

Mine Rescue Mission in Underground Mines

There have been multiple scenarios developed where a drone can provide the critical linkage between rescuers & trapped miners. In one promising scenario, an unmanned underground vehicle (UGV) & drone are paired to operate in a GPS denied environment. In this scenario, the UGV drives to the location, while scanning the area with LIDAR. The drone would then fly at the appropriate time & location to assess the collapsed area & attempt to identify a gap through the rockpile or soil.

Mapping of Abandoned Mines

Millions of abandoned mines worldwide pose multiple environmental, health, & safety threats to communities & current mining operations. From collapsing to methane leakage, illegal mining & more, the risks are endless, but to catalogue vast underground spaces manually is dangerous & an impossible task. Instead, we can use drones to provide a range of solutions such as gas detection, pillar mapping, mine shaft investigation, filling material calculation, rehabilitation & more.

It’s clear that drones have a role to play underground, but in a fluid & dynamic environment, whereby new obstacles are being created hourly, we need to develop solutions that are robust, & that can also operate independently which can mitigate risk & make operating underground feasible. We’ve seen a number of innovations in the last 12-months emerge, which do provide solutions to key challenges & the opportunity to scale. One of the most promising is Exyn’s AI drone platform, which reportedly can fly itself into newly excavated blasted areas or GPS denied without signal or pre-loaded maps. By fusing sensor data, the drone AI is able to map the space, which then allows it to follow its next steps determined by the mission director.

As mines inevitably deepen & we continue to prolong their lifespans; operating drones at an industrial scale underground will always remain a challenge. Despite the advances in sensors, cheaper & more robust drones, the challenge is not just hardware, it’s also linked to our imagination of what can we do & the creation of applications to make mining underground safer & more cost effective. As Nader Elm, Exyn’s CEO said, we have the iPhone, but we don’t have the Appstore.

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