Published in the March 2011 Australian Longwall Magazine

Collisions, whether they are vehicle-to-vehicle, vehicle-to-pedestrian or vehicle-to-infrastructure, have long been a significant safety concern.

On the solutions offered by several suppliers targeting underground coal mines, some industry circles plan to ensure they are specifically tailored to Australian conditions.

Xstrata is well aware that collision avoidance is a global problem facing all mining industries, and the company formed a team to consider methods to reduce hazards across all of its coal divisions.

After conducting risk assessments to determine the hazards and existing control methods, the project team made its own recommendations on new controls.

“A number of hard control methods were highlighted in the risk assessments that could enhance existing controls which were mainly soft in nature,” Xstrata Coal Queensland general manager engineering John Snape told Australian Longwall Magazine.

“Specifications have been developed using functional safety concepts where electronic control methods are to be used. The functional specifications are part of a structured, engineered approach to the problem.

The functional specifications are all about how Xstrata Coal requires the equipment to operate and what level of reliability it requires, based on the safety integrity level that the quantitative risk assessment determined.”

By press time, the key suppliers have probably received those specifications.

Snape said the specifications would allow suppliers to start their own evaluation processes to determine what equipment could be trialled at Xstrata Coal’s sites.

“The process is about knowing what you want and then getting industry to build it for you,” he said.

Industry interest is reaching new peaks, with more than 300 delegates attending both days of a free workshop held by Industry & Investment NSW on the technology options in February.

The aim was to bring end-users, suppliers and original equipment manufacturers together into one open forum where they could be updated on the technology offerings and raise questions.

Queensland senior inspector of mines Tilman Rasche chaired the Sydney workshop after organising a successful one on collision- avoidance technologies back in 2009.

Organiser and I&I NSW inspector of electrical engineering Steve Bentham said the Sydney workshop basically followed on from what was done in Queensland, but there was more to come.

Plans are underway to host another three smaller but more specific workshops in the state before June, including one just on underground coal mining requirements.

“The timeframe of three months was put on to see where we are with the certifications,” he said.

Bentham said specific legislation mandating the use of proximity detection and collision-avoidance technology is not planned to be introduced in NSW, especially as the mining states continue to work on harmonising their mine safety laws.

But he said it would be “reasonable to expect” the installation of those systems would be covered under the hierarchy-of-control provisions of existing state laws.

Personal protection equipment is not specifically mandated for either, but falls under the bottom rung of the hierarchy of controls for worker safety.

Consequently, Bentham said proximity detection requirements were arguably in place, with mines looking to embrace the technology once it gets certified.

Bentham was also supportive of Xstrata’s approach to issue functional safety-based specifications, as he observed that suppliers were promoting technology tested overseas, but might “not necessarily work under our work practices”

“Functional safety is about unpredicted failures, basically saying that, yes we might have a failure once every 1000 years,” he said.

“Well none of the suppliers at the moment are actually on to that, they are currently working on it because that’s what the Australian market has demanded.

“It’s to make sure it’s reliable because this technology is really the last line of defence.”

The underground coal mining market can be tough to crack, especially as mines regularly prefer free trials of new equipment, but Becker NCS is well positioned to gain an early foothold.

Becker chief executive officer Tony Napier said several major mining companies were looking to trial its gear in their underground coal mines, along with a couple of mining contractors.

“Amazed by the response” to his presentation at the recent workshop, Napier said the potential uptake of Becker’s triple detection technologies system is significant.

Fully patented, the system uses electromagnetic technology for proximity detection from zero to 10 metres, time-of-flight radio frequency identification radar to cover zero to 50m, and less-accurate but long-range Ultra High Frequency radio waves to provide detection for within 100m.

All three systems work together and, as it uses a fourth-generation receiving unit, Napier said a lot of the previous ergonomic and operator-interface issues have already been addressed.

He expects Becker’s system to be approved as intrinsically safe (IEC Ex) by early April in NSW, while he said it could be up to another two months to get this approval for Queensland.

The system already received South African IS approval in December, while demonstration gear has been flown over to its Australian arm.

As for proximity detection of workers as they walk under shields on the longwall face, Napier said a few companies had expressed interest in this application.

Becker is working on a “slight” modification to its receiver to suit this need, with the time-of-flight aspect of its system expected to provide best coverage in this regard.

Mine Site Technologies is developing a solution for worker positioning on the face issues at Whitehaven Coal’s emerging North Narrabri mine, with the new Bucyrus longwall scheduled for commissioning in late 2011.

MST business development manager Denis Kent told Australian Longwall Magazine work at Narrabri would be more of a tracking application, rather than a proximity detection one.

“There are some devices common to both, such as the RFID tag we have in the cap lamp and a low-frequency magnetic field to create stable detection zone, but the longwall tracking system is just that, a tracking system.

“We track a miner along the face and raise alerts if he goes outside the designated safe zone along the face.”

In this case, the mine has specified the safe zone as between the shield legs and the rear of the shield.

“Initial trials have been completed on groups of five or six shields, we are now planning trials on a surface mini-build of 40 shields, to confirm performance before building up the entire face length,” Kent said.

“Timing is dependent on Narrabri, at this stage the wall is due for delivery in late 2011.”

MST is well down the path of gaining coal mine certification for a proximity detection system for use around continuous miners and shuttle cars, as well as outbye vehicles.

The recent Sydney workshop helped confirm itsproximity detection system met base requirements, Kent said.

“The underground coal mines are very keen to invest in some system to prove it in their environment with the intention to widely deploy if it meets their requirements.

“The only reason they haven’t begun any long-term trials is that there is no system available that is certified for use in Australian coal mines. We are hopeful that by mid-year we will be in a position to deploy initial, certified systems.”

Specifically, he expects the on-vehicle hardware for mobile machinery such as continuous miners and shuttle cars to be IS-certified in April for NSW and Queensland mines.

The personal alert device is expected to get this certification in June.

Both Becker and MST are confident of gaining a good share of the underground coal market for collision avoidance technology.

Going by the industry feedback at the recent workshop, Napier said everyone who came to see him believed Becker had the most advanced solution that was certainly suitable for underground coal mines.

Kent said MST’s HazardAvert technology was well proven in South African and US underground coal operations.

“Once actual installations can be undertaken and the mines compare system performance and reliability, we are confident that our system will be amongst the most preferred systems,” Kent said.

NLT Australia managing director Tim Haight chose not to make a presentation at the recent workshop, but attended both days and did not see too much progress.

“Unfortunately as an industry, we are not much further than we were before,” he told Australian Longwall Magazine.

“There is a lot of technology available now but most are still approval-pending and, of course, a clear direction and scope from the customer is not fully in place.

“Personally I think there is still a real question mark in the minds of the mines themselves, and what they want as far as a system goes.”

NLT will also target the underground coal proximity detection market and aims to get a supplemental approval for magnetic field tags, to work with its wireless communications gear.

Haight expects an approval for the magnetic tags by June, while a possible, additional and separate radar-based approach for proximity detection would make use of flame-proof enclosures.

The current, approved NLT hardware does not match the same level-of-accuracy claims for proximity detection as Becker or MST’s systems, such as working within a defined space of 1.2 metres with accuracy down to centimetres, Haight said.

But the supplier will be aiming to work with multiple vendors to provide the most flexible solution for its customers and the accuracy claimed by others with the introduction of magnetic tags and radar.

Given the amount of contractors which work in different mine sites, he was concerned at the possibility that workers might have to carry two different sets of tags, to be used with competing proximity detection systems.

Or worse is to have to retrofit proximity hardware from another supplier should a new or hire machine come onto or be shared between sites, Haight said.

From his discussion with mine sites, Haight said the industry might need to come up with a common tag protocol that all manufacturers design to.

Given the operational uncertainties, he was not entirely convinced certification of proximity detection systems would result in a rush to purchase the products from mine sites.

However, Haight was pleased with Xstrata’s proactive stance on the issues with the technology and by its move to specify its requirements to suppliers, “which we haven’t had”

NLT has a trial lined up for a NSWlongwall mine which will use its reverse tracking gear to detect where workers are within 2m zones on the face. Once the system has completed a run-in period, two other mines have already committed to moving ahead with the system.

Management might also get the chance to see animated depictions of the miners walking underground on their web browsers through associated software produced through its collaboration with 3D visualisation company VRT Systems.

Proving that collision avoidance is on the radar of mining industries around the world, some of the conference attendees flew over from America while a chief automations engineer from Voestalpine made the journey from Austria.