Making laser-scanning safe for underground mines
Laser scanning offers rapid, accurate and flexible capture of real-world data, but in a volatile, methane-rich underground environment such as a coal mine, the technology needs to be secured within an explosion-proof container.
Every piece of equipment for an underground coal mine must be certified for that environment.
Even an aluminium can is a potential spark hazard if it gets crushed by a vehicle.
Electronics are an even more complex challenge: if explosive gases such as methane penetrate the equipment, any failure of electronics that causes a spark could lead to an explosion.
The size of the equipment and difficulties in sustaining reliable operation when it’s enclosed to this level has meant that laser-scanning technologies have had limited uptake in the mining industry.
To overcome these issues, we developed ExScan, a new laser scanning and imaging system specifically designed for use in explosion risk zones.
It’s contained in an enclosure that’s been certified to International Electrotechnical Commission ‘Ex d’ standards for use in volatile underground environments.
That means it has been designed to prevent the electronic equipment it houses sparking an explosion.
Inside this container, the ExScan system includes a powerful sensing platform that can be deployed in remote and automated mining applications.
The laser scanner and associated software can generate real‑time 3D maps of tunnels, walls and cavities underground, where GPS does not penetrate.
The 3D maps ExScan creates can then be used for locating, steering and navigating equipment and vehicles.
The ExScan looks a little like a mini version of the Star Wars robot R2-D2, with a steel base topped by a screwed-on polycarbonate dome.The laser sits under the transparent dome and scans through it.
To get outside into a volume of gas, any spark generated would have to work its way through a narrow sawtooth path formed by the screw thread, and in doing so, would lose most of its energy.
Should the scanner malfunction or the container become damaged, it can be swapped over in a matter of minutes, because the dome just screws off.
ExScan improves the capabilities of other automation equipment, too.
Our LASC automated equipment occasionally needs hands-on measurement by workers to guide it through trickier parts of coal seams.
ExScan can provide images that can be used to make those measurements automatically.
The ExScan system
- helps to make remote operations safer and more accurate by providing situational awareness in explosion risk zones
- provides steering information for longwall systems by measuring face creep, retreat and roadway height in real time
- creates accurate 3D maps of the underground environment by incorporating camera, radar and other sensor data
ExScan operating in Australian mines
Already used in six Australian mines, the ExScan technology can be integrated with existing LASC information systems or used as a standalone sensing and scanning solution.
Our team used computer modelling to develop a dome that can be manufactured by injection moulding, meaning that the ExScan devices are relatively inexpensive to make.
For example, they are affordable enough for a line of 40 or 50 to sit behind the mining equipment along a longwall face of 400-500 metres in length, providing real‑time updates of the condition of the coal seam. At 10 metres apart, their scans overlap, which means that if one fails, the others on either side cover for it to ensure overall reliability of the data.
The scanners can be mounted in any orientation, even upside down, and on moving machinery and vehicles, which means they can be used to map whole mines, and potentially for vehicle navigation.
We are currently determining the next steps to commercialise the ExScan system.