Sensor and Sensibility

Sensor technology seems of unlikely importance to the mining industry, but in recent years it has proved pivotal to the development of new technologies capable of increasing productivity and safety within operations. Nowhere is this more likely to be the case than in Australia, where the Commonwealth Scientific and Industrial Research Organisation (CSIRO) has been busy researching a number of projects that rely heavily on sensor technology.

The country’s national science agency is rapidly rising in stature among the global mining community, having developed a number of solutions that have gone on to be adopted by the commercial sector. The government-funded research organisation first became involved in the mining sector in the mid 1990s – coincidently for a project that has only recently proved fruitful, thanks in no small part to the role of sensor technology.

The right timing

Often working in tandem with key industry players, CSIRO can spend anywhere from a couple of years to a decade researching and trialling technology protocols before launching into the commercial sector. In 1994, the organisation began a project aimed at developing automation for drag lines in open cut coal mines. The system is applied to large cranes used to rip the rocks from the surface following blast drilling and uses sensor technology to create digital terrain mapping of the often unstable ground below.

Although the system still requires an operator onboard the crane, the system brings a degree of automation to operations, therefore theoretically adding greater efficiency and precision. Given the hundreds-of-million-dollar values of some of these vehicles, the technology also has fierce potential to remove some of the maintenance costs often picked up from the brutal nature of the job.

The CSIRO’s science leader for robotics Jonathon Roberts says overall he believes now is the right time for the project to finally prove fruitful.

"This is a very old project and one of the reasons our group first came into existence. We have now done two proof of concept projects, where we have tested the system on large cranes for a few weeks at a time – the last one being back in 2004. As with most of our projects, the technology is on the leading edge and it has since been a case of the industry catching up," says Roberts.

"The technology has matured and the sensors are now more robust and available off shelf at a reasonable price. Also the expensive computer systems we used to process the information in the mid 1990s can now be replaced with a standard ruggedised laptop. Finally, there has been a huge drive from the mining industry itself to improve efficiencies at existing mines."

Laser quest

The sensors utilised in the Dragline Swing Assist (DSA) project are laser scanners, which measure the distances to and from objects via laser beams. In this instance, the laser sensor sits on the axis of the crane, rotating around until it builds up a picture of the ground underneath. The technology stems from a system originally designed for factories to prevent human contact with dangerous equipment – whereby the laser beams would trigger the equipment to stop if its boundaries were breached.

It first emerged in the mining sector when the technology evolved into a mapping aid device for surveyors. The transition into the DSA project was, however, not so simple.

"The early system could understand its own positioning but not where the ground was, so the operators in effect had to train the sensors. This meant we had to be very conservative when swinging the boom as the precision was not yet in place," Roberts says.

"With the sensors now available we can develop systems so that the machine itself monitors the ground and is able to adjust according to the change in heights. As the machines are offloading material each day and bulldozers are moving around, the sensors must be constantly kept updated to know where exactly everything is."

Going down under

The sensors’ value above ground has also been put to good use underground. Another CSIRO project aims to create a robotic truck to automatically load explosives for blasting the underground tunnels. Also at a proof-of-concept stage, the project has a distinct eye on safety as it sets about automating one of the most dangerous mining duties.

By scanning the whole tunnel, the sensors are able to automatically locate the drilled holes and a robotic arm, which uses vision technology, is implemented to feed the explosives into the slot. "The system therefore initially relies on laser scanners to find the hole, before the cameras are used to finely manoeuvre the explosives into position," says Roberts.

Unlike the DSA project, which only caters for a very niche segment of the industry, the automated explosive trucks project could potentially have more widespread implementation. The volatile nature of the job has led to years of research into a full proof solution. Remote control trucks have been implemented in the past – firstly with the driver operating the truck at the entrance of the blasting tunnel and secondly controlling the truck entirely remotely from above ground. The first only increased casualties while the other seriously hindered productivity.

"The only solution was to make the trucks more automatic. They can drive full speed and there is no safety issue – so finally we have a much-needed solution that offers the same productivity without placing people in danger," Roberts says.


The butterfly effect

Evidence of sensor technology already making an impact in the commercial mining world is strongly apparent in CSIRO’s automated haul trucks project. The concept is currently being successfully commercialised by global truck and mining equipment manufacturing giants Caterpillar.

Relying on laser scanning sensors to construct a cross section of a tunnel, which is then fed into the truck’s steering system, the automated haul vehicles completely remove the need for a driver.

"Although the mining industry is conservative, it seems that a lot of new equipment being purchased has these systems built into them. So where fleets are being replaced, this technology is being embraced," says Roberts.

"Sensor technology has certainly taken on a more central role at the CSIRO, although a lot of that technology is being driven by other industries, most notably the automobiles sector. The drive to install these sensors onboard cars for automated parking systems and cruise control is ultimately leading to their mass production, which will cause the overall cost of the sensors downwards," he adds.