Published in September 2008 Australian Longwall Magazine
Proximity detection has passed proof-of-concept stage with an “inner zone” product expected to be released around the end of the year.
The importance of proximity detection in risk management has reached a crescendo with a number of recent near misses and two fatalities. In 2007 a Queensland underground coal miner was fatally crushed by a shuttle car and this year a miner was crushed between two vehicles at an underground metalliferous mine.
“The hazards of working near mobile mining equipment are often underestimated, with incidences involving crushed light vehicles, passengers or bystanders still occurring too frequently,” said the Queensland Department of Mines and Energy.
“It was encouraging that some companies are already trialling a system or consulting with manufacturers to scope and design proximity detection and warning systems. However, a more rapid change in personnel safety will only be achieved as more sites actively adopt the technology to provide a broader testing ground.”
Industry has answered this call recently completing an ACARP project to bring the technology closer to commercialisation.
Intimately involved with the project is MST’s Denis Kent who said a number of factors had come together as a catalyst for the technology’s development.
“Our tracking technology development had matured into a reliable product being installed in some mines, plus we had developed a machine mounted processor/datalogger/wireless bridge module for remotely monitoring vehicle diagnostics and communicating via wireless networks,” Kent said.
“So now we were starting to get a bunch of miners running around underground carrying RFID tags, plus an intelligent device on board vehicles that could potentially process a range of inputs, so we considered what else the technology could offer.
“Then Xstrata Coal in New South Wales approached us after also recognising there may be some potential to extend our tracking technology into some type of people/vehicle control system. Xstrata had identified the need to look for better ways to help control the risks associated with the use of vehicles underground.”
MST and Xstrata sought funding from ACARP for the project. During this process Centennial Coal also expressed interest in the system and gave its support to the project with input into risk assessment and trial sites.
The aim of the ACARP project was to bring a proximity detection system to proof-of-concept stage. To do this, MST developed technology based on its ImPact Tracker tagging technology.
The concept uses active RFID tags worn by miners underground to be detected by vehicle mounted readers. The readers provide outputs to alert the driver, such as a light or audible alarm, that a person is within the vicinity of the vehicle.
Kent said the prototype developed proved active RFID tags were able to send out signals for detection by vehicle mounted receivers and receiver electronics could detect RFID tags approaching at 60-120m. It also featured a transmitting device to enable an inner detection zone (5-20m) and a software/hardware device to process and log incoming tags and create outputs.
During the development both Xstrata and Centennial provided input on design specifications, participated in risk assessments and trialled the prototype underground.
Laboratory testing and underground trials tested the signal range, the reliable outer and inner ranges and operator interface for the driver to gauge its suitability and ease of use.
Kent said the biggest challenge in developing the technology was the time involved and making the product meet intrinsically safe standards.
“Existing RFID tags were IS, but there were some third-party devices, such as touch screens, that are very difficult to make in IS approved format. Additionally our Vehicle Intelligence module, though operating in hard rock mines, needed to be developed in IS format for the coal mines,” Kent said.
The technology is also being developed into other areas, such as controls for vehicle-vehicle collision and restricting access of vehicles or people into certain zones.
The technology, which Kent said was MST’s highest priority project, has now progressed well past proof of concept.
“We want to release the Inner Zone version by the end of the year or early next, assuming IS approvals will take three to four months,” Kent said. “We will then complete the approval process on the Outer Zone devices which will be designed as an upgrade/add on to the Inner Zone equipment that we hope will already be installed.
“Both these stages will be done with initial pilot installations in one or two sections in a mine, then expand to all vehicles once the performance has been confirmed.”
He added coal mining companies had been “incredibly supportive and encouraging” of the technology and they “just wanted it available as quickly as possible”
