The Nation’s Top Gun in coal miner health and safety said he does not believe the technology will be there to meet one requirement of the 2006 MINER Act. A division of the Nation’s sixth largest defense contractor is out to prove him wrong.

During a telephonic press conference in which Coal People participated in late June, Acting Assistant Secretary for Mine Safety and Health Richard E. Stickler said he did not believe the technology necessary for a successful underground wireless communications systems would be in place before the June 2009 deadline set forth in the MINER Act. However, L-3 Communications Corporation’s Global Security & Engineering Solutions (L-3 GS&ES) division in Fairfax Virginia currently has such a system undergoing tests at a coal mine in Northern Appalachia.

That system, according to Vic Young, GS&ES’s Director of Safety Programs, is the result of a team effort comprised of fellow Virginia-based companies Innovative Wireless Technologies, Pyott-Boone Electronics, and Marshall Miller & Associates, Inc., as well as the Virginia Center for Coal and Energy Research at Virginia Tech.

“Though none of us had worked together before,” Young said, “we all brought different skill sets to the table, including mining expertise and communications experience, making the team greater than its individual parts.

“The wireless radio network we developed—one that allows for communications peer-to-peer (person-to-person), from the person underground to the surface, and from the surface to the person underground—is designed both as an emergency communications system that will continue to operate in the event of a major catastrophe as well as a working tool in the daily operation of the coal mine. Additionally, each radio to be carried by the coal miner has within it real-time situational awareness capability, a tracking system.

“That, however,” he added, “is a bonus to the radio communications system. Under a second NIOSH contract, we also are developing a Miner Location Tracking System. This system, capable of providing real-time—as opposed to snapshot—positioning of every person working underground, was selected by NIOSH last April as the sole program to advance to the system design and testing stage. The underground long term test and evaluation phase will take place later this year.”

Wireless Communications System

Dan Erndle, who has been with GS&ES for 10 years, is the Wireless Mesh program manager. “We submitted our proposal to NIOSH in January 2007 and in May we were notified that we had been selected over 18 other proposals,” Erndle said. “The resultant Wireless Mesh Mine Communications System Program is a 19-month effort that includes both the development of the mesh system and in-mine evaluation.”

As explained by Erndle, the communications “mesh” is created by the radio waves emanating from handheld radios and propagated throughout the mine via strategically placed mesh nodes and their antennas. “Envision an overhead mesh, a large net,” Erndle offered. “The lines of that mesh represent the emitted radio frequency energy and the mesh nodes are relay points that carry those radio waves, or signals, throughout the mine and between the underground and the surface.”

“Each node and a set of miner handheld radios are in themselves a small network. As you add nodes, or antennas, you extend the network. Theoretically, there is no limit to how large that network can extend and,” he added, “no man in the loop is required; it’s all done through the software logic contained in the nodes and radios.

“From the very beginning,” Erndle said, “our goal has been two-fold: One, to fully meet the requirements established in the government contract and, two, to fully meet the intent of MINER Act. As we traveled the industry and learned more about coal mining and the underground environment, we added a third point: To provide a product that would be useful to the mine operator. To meet the requirements of the MINER Act will require a large operator investment. We felt the technology we developed should not only meet those requirements, but also provide the operators with a tool that would benefit operations as well. We believe we have accomplished all three goals.”

According to Erndle, during their travels one chief operating officer told them voice communications was very important to his company.  “He probably speaks for a lot of mine operators, Erndle said. “For one thing, he noted that, with constant voice communications capabilities, when a person is needed in a certain area of the mine, that person can be reached and be directed to where he is needed. And,” Erndle continued, “with the L-3 system, that can be accomplished by voice and by text, all wrapped up in one package. From the reaction of that particular operator, this seemed to present a value to his operations.”

With their company, including the researchers, engineers and technicians on the project, being new to the mining industry, Erndle emphasized the importance to them of getting out into the field. “From the start, we sought information from the mine operators.

“While we realized not all of what we had learned and had been told would be in the first product, we designed the L-3 system so that it could be upgraded in the future without the product having to be redesigned and rebuilt. We wanted to be sure that our system would not have to be re-invented and again be put through the entire MSHA (Mine Safety and Health Administration) certification process. Rather, we want to provide future upgrades that require minimum MSHA review. Many components of the system already have been through MSHA process and, in fact, the last component, the miner handset, is at MSHA now.”

As described by Erndle, the system has three layers: Underground person-to-person, or peer-to-peer, communications; underground to surface interface, and the surface component, the dispatcher or communications center.

“The miner underground carries a clip-on handset, about the size of early portable phones, Erndle said. “This radio provides voice and text communications, as well as having a signal used for location and tracking,” he continued. “Two-way voice and two-way text; miner-to-miner, miner to the surface, surface to the miner. ACCOLADE—Advanced Configurable Communications and Location Awareness Design—is its formal name. The handset is waterproof and dust proof and shock resistant.”

Technology Optimization

“A key to our success to date,” said Erndle, “has been the utilization of a proprietary optimal frequency that maximizes signal propagation. A key concern of the government is radio wave propagation in a coal mine environment. During developmental testing underground, we successfully have broadcasted radio communications more than 2,000 ft along a non-line-of-sight entry that included a 35-ft drop in elevation. We also propagated that signal two entries over and up several crosscuts.

“Of course,” Erndle added, “every mine environment will be different—the size of entries and their configuration, dips and rolls and dog legs—as will the numbers and sizes of equipment and their dispersal. We have not yet fully mapped our radio propagation patterns and intend to do so later this summer. Our intent is to do that testing in as many configurations as possible to determine our range to develop a deployment model.”

The ACCOLADE system has four components: The Miner Mesh Radio, Fixed Mesh Nodes (FMNs), Gateway Nodes (GWNs), and command central (mine operations center/dispatcher).

As explained by Erndle, communications between two people can be maintained with just the radios, called ”talkaround”. The second system component, the fixed mesh nodes (FMNs), is what establishes the network and makes wider communications possible.

“Throughout the mine,” he said, “we’ll install FMNs, attaching them to the mine roof or ribs. Each FMN, or node, creates its own network and, combined with other nodes, forms the entire network. Finally, the gateway nodes provide the relay to the surface.

“The network of nodes,” he explained, “is like the game of Chinese Checkers we all played as kids. Each marble on the board represents a node, one connected to the other by invisible lines of radio waves. Should there be a problem with one node, whether it be a malfunction or damage from a fall or other event, the logic within the system searches for the most optimum route to another node to maintain the network.

“With the ACCOLADE system, even as the network is reconfigured underground, an indicator in the mine’s communications center, or the dispatcher, alerts them to the disruption, pinpointing its location. In the event communications are lost to the surface, with additional access holes—ventilation shafts or bore holes—surface communications can be reestablished with the operating underground network.”

The Fixed Mesh Nodes operate on a mine’s electrical power system and each node has its own battery backup. According to Erndle, the handheld radios are designed to be recharged between shifts, much like miner caplights. While pricing has not been established as yet, Erndle emphasized the system “will be affordable for mine operators”.

“One thing that was critical to us in designing the system,” he said, “was that it can be integrated into an existing leaky feeder system will inter-operate with our system as the mine expands. Additionally, as we envision it, our system utilization will increase as the mine gets comfortable with it and begins to realize all its features.”

Erndle noted that, in designing the system, they did not simply adapt off-the-shelf MSHA-certified parts. “It was not just a case of functionality,” he said. “Of primary concern to us in the design process was safety, that was paramount. Following those criteria, we have worked with the government and mine operators to help ensure that the L-3 ACCOLADE system not only meet the intent of the MINER Act, but that it also provide a useful tool for the mine operator without being cost prohibitive.”

While the ACCOLADE system includes a tracking feature, L-3 also has developed a stand-alone miner location system that, they say, may have applicability for different mine environments.

Miner Location Tracking System

“Everyone is familiar with the scanning systems used at the grocery and clothing stores,” offered Tom Eldridge, program manager location tracking. “In simplest terms, we and our partner—Multispectrum Solutions, Inc. of Maryland—took that system and reversed it.”

Barcodes and scanning today are employed virtually everywhere to maintain inventory control. An item is tagged with a barcode and that barcode is scanned as the item is moved from the manufacturer or producer to the shipper, to the warehouse, to the ultimate user or purchaser.

“In our reverse radio frequency identification system,” explained the retired Senior Chief Petty Officer, “rather than barcoding the inventory—the miners underground—and passing them over a scanner, we are barcoding the mine and putting the scanner on the individual miner.”

Developed under a second NIOSH contract, the Miner Location Tracking System calls for the placement of radio frequency identification tags at each crosscut throughout an underground coal mine, with each individually coded tag corresponding to an exact position on the mine’s map.

Each miner, then, wears a belt-mounted portable tag receiver/repeater, with a sending antenna integrated into his or her caplight. As the miner passes a fixed-position tag it is read and stored by the reader. At predetermined intervals, the stored location data is transmitted to the surface where it is displayed on a terminal, providing real-time locations of all the people underground wearing a device.

“How often that information is transmitted will vary,” Eldridge said. “The tradeoff always is between battery life and how often the information is to be transmitted; it reads constantly, not transmitting constantly. Still, even at this stage, it is very good, down to tenths of a second. Now, it could be that once a minute is all that is needed to meet the objective of tracking a person but, if we can do better than that and maintain battery life, why not?”

According to Eldridge, “The system’s ultra wide band (UWB) technology gives a very fine time resolution for very precise positioning. What UWB does is blast out wideband simultaneously in very short pulses, so short that there is no interference as there is with narrowband.

“With this, the reader does not read just one tag, it reads at least two, what is referred to as multispectral solicitations, Eldridge explained. “The strength of the signal from each indicates where that miner is at that moment in relation to the two tags, making it possible to calculate his or her position to within 50 ft. I call it ‘proportional common sense’. Say, for example, of the two nearest tags to the individual one is one-third the strength of the other, then you know that individual is closer to the one with the stronger signal. It’s a dynamic system, always adjusting to know where the person is located. With this dynamic positioning, the reading is done constantly; it’s not just a scan, not done in gradations.

“Other tracking systems lack this capability,” Eldridge said. “Other systems indicate where miners being tracked have been, not where they are at the moment. Our system also has ‘situational awareness’ capabilities,” he added.

“Each tag has an identifying serial number. If that tag isn’t read within a predetermined amount of time, an alert will appear at the situational awareness display. This will alert the operator that either the tag is non-operational or somehow has had its transmission blocked by an object or been dislodged from its mount. Mine personnel then can rectify the situation by either replacing the tag or remounting it,” Eldridge said.

“Even if you reversed the reverse of our system back to a typical inventory control system of labeling the individual and having the scanners in fixed positions, that would only indicate that a person is walking by; it would not actually track his or her movements as does our system. Not only that, but the cost would be prohibitive. Depending on the size of the mine, you conceivably would be putting out hundreds of high cost scanners to cover the entire mine and putting the very inexpensive tags on a relatively few number of people. That wouldn’t cost cents, and that wouldn’t make sense.”

According to Eldridge, the tags have a 10-year life operating on AA batteries, have no moving parts to wear out, are extremely durable, and are easily replaced. “We just recently developed a permanent mounting device, making the tag unit about the size of a small 3-4 in. maglight many sportsmen carry in the field. After the initial installation of the tracking system throughout the areas of interest in a mine, new tags will be set as a matter of routine as the mine advances, such as when the engineers set their spads.

 “The reader a miner will wear is comparable in size to a king-size cigarette pack,” he continued. “If incorporated into the miner’s caplight battery pack, it will not increase in size or weight significantly.”

At present, Eldridge said the company is looking to partner with a caplight manufacturer. “Originally,” he offered, “we thought incorporating it into the battery would require a larger battery but, with the smaller but more powerful batteries being developed today, we see the casing staying the same.”

Meanwhile, Eldridge said, having completed underground testing of a concept demonstration system, a final design for the prototype system will be submitted to NIOSH this summer. “That system,” he said, “will be run until confirmed it works; then there will be a final report. After that, it’s NIOSH’s call.

“We think we’ll know pretty quickly how well it works over an extended period of time as a fully integrated underground system. We fully expect it will and work well, and that we’ll have a good idea of the level of maintenance that will be required for the system when put into use. I served on nuclear submarines as a senior weapons system technician. One thing you learn quickly on submarines, when you look at something coming aboard you ask yourself: When will it break? You don’t want bells and whistles; what you want is the confidence of knowing that, ‘If it don’t break, you don’t have to fix it’. That’s the kind of system we’ve designed.”

According to Young, who is directing both programs, though mining is new to them, they see a bright future in it. “As an outgrowth of these two programs,” he said, “L-3 Communications currently is developing a whole new business unit that will concentrate on the mining industry. We are hiring a sales force, we have brought in a media company, we have position descriptions for a good-sized staff for installation of our systems and we anticipate augmenting our sales force by bringing in well-known, well-respected contract distributors.

“We’re new to coal mining,” Young acknowledged. “Every day we are learning something new about the industry and we are enthusiastic about it. Already, we are in initial discussions for a ‘coal mine of the future’ concept, one that will have an augmented mesh radio system providing underground video capabilities.

“At this juncture,” he added, “what we see is an opportunity to help; to help make coal mines safer and to help ensure that miners come home after every shift. That’s a role we look forward to fulfilling.”