When smaller vehicles get in the way of a mine haul truck, the consequences can be dire. A recent accident in South Africa shows just how serious mine haul truck and mine site vehicle collisions can be, according to CSIRO senior scientist project leader Patrick Glynn.
“As a light vehicle came in between two haul trucks, dust hid the small vehicle from the second truck, and it ran straight over it,” Glynn told Australian Mining.
“If they had a proximity detection device on the vehicle, they would have been able to take evasive action.”
Glynn says there is no magic bullet for mine operatos looking to avoid mine haul truck collision on their site.
“As the trucks get larger, the problem of collision gets magnified,” he said.
“Full open cut mine automation may be the only solution to this problem, but this proves to be incredibly costly.”
Glynn is leading a research project to develop a collision avoidance and 360° proximity detection system for mine haul trucks.
“There was little research in the area of mine haul trucks,” he said.
“Systems developed for road going use have been migrated across into the mining industry, but road going radar was designed with highway driving in mind, and not mine site applications.”
The distance ahead of a driver sitting in the cab of a haul truck is about 30 m, and anything within that 30 m can not be seen effectively.
“What is required is something that will give proximity out to 30 m, and notify drivers of anything that encroaches upon that area,” the CSIRIO senior scientist said.
Radar used for collision avoidance in highway applications has a field of vision of between 3° and 11° at 100 m.
“The mine vehicle needs to have a field of vision of 360°,” Glynn said.
“We have had to go to another technology called Doppler-shift, which uses multiple radar antennas with shorter range, and a wider aperture and field, to about 70°.”
Haul truck drivers today have a better sense of mine safety and the limitations of vehicles, according to Glynn who says there are three challenges in developing the technology.
“Firstly, mine managers want technology that is robust, that does not result in the trucks being taken off the road,” he said.
“Secondly, operators want the technology to work so that it doesn’t give out false alarms, which would make the driver want to turn it off.
“Thirdly, the technology must be reliable and deliver accurate readings.
“We have taken a standard Doppler radar system operating on a 24 GHz frequency, and adapted it using microcontroller circuits with integrated digital signal processing (DSP),” Glynn said.
Operators will be able to decide if a hidden object is moving relative to their vehicle, what direction the vehicle is moving, what its rate of change is, and if it is going to hit the vehicle.
“In all cases the system will report to the driver in .1 of a second, with the reaction time for the driver at about one second,” Glynn said.
Operators already have a lot on their hands, and taking their eyes off the road is something Glynn is keen to avoid. For this reason, the system’s driver interface has been a challenge for the researchers.
“We have looked at everything from speech synthesis verbal warnings to background beeping to Australian standards,” Glynn said.
The research is still in its development, and a prototype of the technology has been tested at Goonyella riverside.
“We are probably going to tie in the system with a reversing camera and DSP monitor to show where a detected vehicle is. The system will indicate the location of the detected object relative to the truck on the same display, using graphics,” Glynn said.
The major challenge with the technology is that the radar used can not discriminate between a large object at a far distance and a small object close by the vehicle.