Despite great strides in health and safety regulations, mining remains an inherently dangerous profession, with the enclosure of workers underground presenting a range of threats, from collapsed tunnels to exploding hardware. With this in mind, many mining companies and technology manufacturers have invested in remotely operated technology and automated systems to sidestep these entrenched risks by removing workers from mines altogether.
Australia’s national science research agency, the Commonwealth Scientific and Industrial Research Organisation (CSIRO), has been at the forefront of this trend, already investing in projects such as remote tracking technologies and smart drones to map underground mines. Now, the organisation has announced its latest innovation, a laser-based scanner known as ExScan that could enable workers to map out entire mine complexes from the surface, removing the need for people or even automated drones to enter the subterranean tunnels.
Developed in line with safety requirements put forward by the International Electrotechnical Commission (IEC), and already trialled at mining majors such as Glencore, the combination of intricate design and industry support could see the scanner make a significant impact in the Australian mining industry.
Safe scanning and clever containing
CSIRO has a well-established history of using tracking technology in mines and subterranean environments; its wireless ad hoc system for positioning (WASP), first deployed in 2013, enables above-ground operators to track the relative positions of employees whose equipment is fitted with tags feeding information back to the surface. The WASP system also enables employees to be placed within a three-dimensional map of a mining complex, and the ExScan technology is the logical extension of this model, as it can create these complex maps and blueprints in real time.
The scanner itself is a small, roughly cylindrical unit 25 centimetres tall, with a clear polycarbonate dome on the top. The laser sits beneath and emits lasers through the plastic dome, which can penetrate rock and mineral deposits to ‘see’ beyond the range of conventional GPS systems, building up a three-dimensional map of a mine in real time, as the scanner moves through the subterranean tunnels.
The design of the scanner’s casing, however, is perhaps the project’s most impressive technological accomplishment from a safety perspective, with CSIRO saying that the “real innovation” is “not the smart laser-based scanner, but the container in which it sits.” One of the greatest dangers for underground mine workers is that of an explosive spark, triggered by the concentration of particular metals, or the build-up of static charges on surfaces such as plastic, interacting with dust and particulate matter in the air.
A report published in CIM Bulletin found that these sparks can cause explosions hotter than 2,000°C, and the nature of underground tunnels can make sheltering from such detonations impossible, and raise the possibility of a collapsed ceiling trapping or injuring workers. To overcome these risks, the ExScan casing is made of steel, a metal which lacks the aluminium, magnesium and titanium elements that are the most dangerous with regards to triggering explosions, and the plastic dome can be easily removed from the unit and replaced, should it become damaged or scratched and begin to collect a static charge.
External certification and industry testing
The technology does not exist in a vacuum, however. The devices have been awarded the ‘Ex d’ certification by the IEC, a global body that aims to advance electrical and electrotechnical devices in the workplace and is heavily involved with safety compliance and testing. The Ex d designation means the ExScanners are considered to have a “flame-proof enclosure” that can withstand internal explosion, and survive sparks and ignitions originating from within their systems.
In practice, this means the scanner is structured in such a way that volatile and moving parts are separated from the outside atmosphere via a series of screws, so any sparks that do originate from within the device will have to travel along what CSIRO calls a “narrow sawtooth path” to reach the gas outside, by which point the spark will have lost much of its energy; this effectively adds an additional layer of security to the system’s spark-proof design as, should the device’s safe metal body and removable plastic dome fail, an internal explosion is not expected to tear the scanner apart and pose a risk to human workers.
This design was completed as part of the Australian Coal Association Research Program, and the combination of scientific investigation and external certification demonstrates the effectiveness of this collaborative approach to safety compliance.
The ExScanner has not simply been developed in theory, however, and this collaborative approach extends to the practical testing of the device. The scanner has been trialled extensively at Glencore’s Oaky Creek coal mine in Queensland, Australia. The mine, which produced over seven million tonnes of coal in 2014, initially took on 16 of the scanners, and deployed them up to 400m underground to construct images of the coal face beneath the mine. The units were also subjected to more than 50 explosive tests as part of their safety certification, and appear to have impressed the miner; Glencore announced plans to increase its stock of ExScanners to 50 by the end of 2019.
Exploration without endangering
The ExScan technology is the latest in a series of innovations that aim to improve efficiency and safety in Australian mines. Following on from its investment in the WASP project, CSIRO has been involved in projects such as Emesent’s Hovermap drones, which can autonomously enter and navigate mine shafts to construct images of their interiors to aid in exploration efforts.
The Hovermap drones have a significant safety advantage over many other solutions in that they remove human workers completely from underground chambers, and the success of Emesent’s project could point to a future for the ExScan technology, where the scanners can navigate passages without the need for hands-on human control.
This trend could be particularly important in reducing the number of employees affected by explosions, the primary danger posed by new innovations such as the scanners. By removing human workers entirely from underground operations, the risk of explosions to human life is all but removed, and could help to sidestep some of the dangers that have affected mines in recent months, such as the trapping and presumed death of a Tasmanian coal miner in January caused by the collapse of a tunnel’s ceiling.
The Mine Safety Institute of Australia recorded 63 accidents involving three or more fatalities between 1882 and 2000, with 665 workers killed across these incidents. Of these deaths, 442 were related to explosions, and while the safety compliance of Australian mines has improved over the last two decades, the threat of explosions is a thus-far inescapable part of mining, and one that ExScan could help eliminate.