Once considered the answer to many of the significant communications challenges facing underground coal mines, leaky feeder-based systems have not received the market acceptance some suppliers hoped for. Now it seems they may have got their wires crossed.
In many cases, mines that have invested in leaky feeder systems have not received their promised full potential, the reasons ranging from incomplete IS (intrinsically safe) approvals to a range of technical hitches. During the past year or so many suppliers have taken a step back from pursuing onorous approval processes necessary to take leaky feeder systems with capabilities beyond two-way voice communication into an underground coal environment. They say the Australian market is simply too small to warrant the time and expense required to get equipment used in metals mines or other countries, such as the USA, modified and certified for local use. In addition, the “tweaking” that accompanied the introduction of the technology into metal mines during the early 1990s is not possible given IS restraints.
Mine Site Technologies Pty Ltd, which has its one-way PED system installed in several local and international coal mines, has delayed the process of getting its VDV (voice, data, video) leaky feeder radio system approved for underground coal operations. Said Denis Kent, Mine Site’s business operations development manager: “Most importantly, once VDV’s deliverable performance specifications are defined, these are what will be used for market assessment, not promises based on market expectations. A simple, but an often disregarded, philosophy.”
Despite all this, many longwall operators remain committed to the idea of a leaky feeder radio system, saying it offers unprecedented management opportunities — if it works properly. The ultimate aim? To provide the links for a completely automated longwall face.
Many argue leaky feeder systems are capable of offering a backbone for data, voice and video communication, the latter the key to longwall automation. What remains unresolved are IS regulations governing all ancilliary attachments, such as video cameras and battery supplies. To date it would appear no underground Australian coal operation has yet been able to get true video functionality and only indifferent data functionality. Moranbah North, one of the most recent purchasers of a leaky feeder system from MineCom Australia, is video fitted but the system has not been fully installed.
“From Moranbah North’s perspective we haven’t really pushed it,” said the mine’s engineering and maintenance manager, Mick Sams. “There are too many other priorities building a new coal mine. It’s on the back-burner. In the early days we put the leaky feeder system into the mine but only for a short distance. We haven’t taken it to a longwall panel yet.”
He said the long-term plan was to have cameras underground at various strategic positions like transfer points. Sams expects installation of the system to resume in the fourth quarter and for it to be up and running by the second quarter next year.
“It offers huge management opportunities if we can do it. The PED system is just a one-way communication system while the leaky feeder system is a two-way communication system. Plus we can have tagging of vehicles, and can tell where our people and equipment are underground.”
MineCom managing director Brian Wilson said the trend over the past 12 months had been for mines to issue tenders for a broader spectrum of communications equipment, rather than a single product. “In the past, having two or more different suppliers of communications products at a mine site created numerous headaches for mine managers, like trying to determine why one piece of equipment does not work when interfaced to another supplier’s equipment and each supplier stating that their equipment is working and the problem is caused by another supplier’s equipment.”
Ampcontrol’s Warwick Sommer suggested the greatest impact from leaky feeder would be in the area of safety.
“Once someone can offer a comprehensive personnel tagging solution, probably using leaky feeder as a backbone for voice, data and video, we are going to be able to offer what other people can overseas, which is personnel accountability, more from a safety point of view, but there are other benefits from a mine management perspective. I personally believe it’s going to be an integral part of where Australian coal mining goes,” Sommer said.
It is a view echoed by many in the industry, including El-Equip’s Greg Gibson, who believes coal mines have adopted leaky feeder systems as an additional safety feature. But he added some operations baulked at spending money on a system which did not offer clear-cut advantages over other systems.
“Many think, if such a system is going to cost $200,000 and they’ve got this far without it, they can use this $200,000 somewhere else,” Gibson said. He said El-Equip had largely overlooked the coal market in the past year, but added that recently the company had been asked to provide four quotes for leaky feeder installations, which “indicates something of an upturn to us”
Greg Eaton, BHP Coal technical officer, said the purchase of leaky feeder radio systems for the company’s NSW coal operations was justified under emergency situations. Eaton now believes that because of their limited coverage leaky feeder radio systems cannot be classified as emergency communication systems.
