H undreds of feet under-ground, nearly a mileaway from the mouth of

the mine, a miner realizes heneeds to repair a key piece ofequipment. Summoning anengineer used to mean a longwalk back through the mine or a long wait for the man trip, amotorized shuttle vehicle. While the miner is walking orwaiting, no coal is being dug, so these interruptions add upquickly in lost production. But now, with the push of a but-ton on a wireless VoIP handset, miners can request thatengineering resources be dispatched to a location withoutgoing anywhere. If the VoIP system is connected to the pub-lic phone network, staff in the mine may be able to get serv-ice assistance from equipment manufacturers while at theworking face. In a few minutes, the miner is safely and pro-ductively back to work. Multiply this scenario by dozens or

hundreds of times per week in alarge mine, and there is an obvious,immediate positive impact to thebottom line.

But how did this step- and time-saving exchange take place nearlya mile down the mineshaft? Tradi-tional cellular signals don’t propa-gate through rock, and there’s notime for laying wire phone lines

Compact wireless mesh node andantennas mounted on a support columnare designed for harsh environments.

MinersGive a Nod

to NodesNew mesh networking technologyboosts worker safety and productivity and fulfills new federal requirements.

By Byron Henderson

▼

ONLY OnlineVisit MCCmag.com forthe results of a reader

survey on meshnetworks and more onthird-generation meshnetwork technology.

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that might be damaged by rock fallsand moving equipment. The answer isthird-generation wireless mesh tech-nology based on the Wi-Fi 802.11 pro-tocol. A series of multiradio enclo-sures, called wireless mesh nodes,propagate the signal down the lengthof the mineshaft and wirelessly con-nect miners working or traveling near-by. The nodes may be placed alongentries, travel ways, beltways or in air-way intakes and returns to wirelesslylink miners at the working face to therest of the mine, as well as to theoffice and managers outside the mine.

Improving Safety and Response

Besides the time-saving productivi-ty boost, the wireless mesh nodes alsoprovide infrastructure that delivers life-saving miner location and communica-tions capability in case of an accidentor disaster. Preserving the safety ofunderground mine personnel has beenan important focus of government andindustry. In the aftermath of the Sagomine disaster, a coal mine explosion inSago, W. Va., in January 2006, the fed-eral government set in place atimetable for underground coal-miningoperations to upgrade procedures,equipment and technology with thepassage of the Mine Improvement andNew Emergency Response (MINER)Act in 2006. Major elements of theMINER Act require a wireless two-way medium of communications andtracking of individuals by 2009. Awireless communications system thatprovides two-way communicationsbetween underground and surface per-sonnel and an electronic tracking sys-tem that allows surface personnel toindependently determine the locationof anyone trapped underground is keyto meeting the requirements. New Wi-Fi wireless mesh technology delivershigh performance and reliability at lowcost over long distances in under-ground coal mines in numerous pilotand production mine networks,because it allows for reliable two-wayVoIP communications and Wi-Fi loca-tion tracking.

Mining network communicationsand tracking supplier Active ControlTechnology (ACT) of Burlington,Ontario, Canada, has installed wirelessmesh technology supplied by Mesh-Dynamics in a number or mines.

Underground Coal MinesUnderground coal mines, both

“long wall” and “room and pillar,” arechallenging settings for wireless com-munications. There are often multipleadjacent entries (tunnels) into the mine.At the least, the network must providecoverage in the belt entry, the maintravelway, primary escape route andfor the working unit at the mine face.Another challenging characteristic isthat the mine is constantly changing:The working unit progresses forwardeveryday, and therefore the supportinginfrastructure must move with the unit.Any communications systems must beeasily deployable, configurable andresilient.

Because of the vehicle and humantraffic and hazards such as moisture,rock fall and vibration, a compact androbust physical device is required. Thesafety and communications missiondemands the ability to work from bat-tery power and for isolated portions ofthe network to continue operation ifdisconnected by an incident. Becausedistances in the tunnels can be quitelong, the mining environment posesunique challenges for real-time dataover many hops.

A recent successful installation in aworking room-and-pillar undergroundcoal mine required long-distance con-nectivity for voice, location trackingand video process monitoring.Because the headquarters and pro-cessing plant is 3.5 miles from themain lateral entry to the mine, multi-ple hops were needed both outsideand inside the mine. In a number oflocations within the mine itself, wire-less mesh nodes were secured to theroof bolt or supporting timbers andpowered by a battery backup system.Individual miners carry wireless Wi-Fi VoIP handsets that provide voiceconnectivity to the PBX at the head-

quarters site, with public switchedtelephone network (PSTN) access viathe PBX. Clear voice connections areprovided at 12 hops to the farthestextent of the current installation.

A miner location and tracking sys-tem based on Wi-Fi is also supportedover the wireless infrastructure, whichhelps fulfill the MINER Act require-ments. In addition, an IP-based videocamera remotely monitors a key junc-tion of the belt system crucial to mineproductivity. The mine operator enjoysmultiple benefits from the installation.Besides fulfilling MINER Act require-ments, mine personnel are instantlymore productive through better com-munications. Requests for repairs, sup-plies, tools and other material may bemade over the VoIP system, saving thetime and inconvenience of multipleman-trip shuttles. The ability toremotely monitor the operation of keybelt locations via video has alsoincreased uptime and productivity.

Surface Mining ApplicationsOutdoor, aboveground mining

sites also require wireless voice, dataand video communications. There isan increasing need for up-to-the-minute status on operations, equip-ment and personnel, as well as astrong move toward mine automa-tion. But because an open-pit mine isa constantly changing landscape, it’snecessary for any network deploy-ment to be simple to deploy and rede-ploy. The wireless mesh nodes actsimilar to “radio robots” to locate one another and quickly establish a network without operator intervention.

The nodes may also be in motionrelative to one another and to fixedelements of the network, yet remainconstantly connected. It’s critical formining enterprises to monitor the pro-ductivity of a haulage fleet and reportthat information back to local and cor-porate management. Additionally,visual monitoring through video cam-eras mounted on mining vehiclesallows for immediate response fromthe control center rather than requiringa manned trip to a location in the

Miners Give a Nod to Nodes

RadioResource MissionCritical Communications delivers wireless voice and data solutions for mobile and remote mission-critical operations. The magazine covers business, publicsafety, and regulatory news; case studies; in-depth features; innovative applications; product information and comparisons; emerging technologies; industry reports and trends; andtechnical tips. In addition, each issue contains Public Safety Report, a special section devoted solely to the needs of the public safety community. Editorial content targets organizationsin the United States and Canada with mobile and remote communications needs, including public safety, government, transportation, manufacturing, utility/energy, business, andindustrial entities. To request a FREE subscription or get more information, go to www.mccmag.com. RadioResource MissionCritical Communications is published by the RadioResourceMedia Group. Pandata Corp., 7108 S. Alton Way, Building H, Centennial, CO 80112, Tel: 303-792-2390, Fax: 303-792-2391, www.rrmediagroup.com. Copyright 2008Pandata Corp. All r ights reserved. Reprinted from the July 2008 issue of RadioResource MissionCrit ical Communications. For more information aboutMissionCritical Communications and the RadioResource Media Group please call 303-792-2390 or visit www.mccmag.com

mine. Extending the network into themine also extends the private tele-phone network into the pit — vital forremote locations that are often withoutcellular service — and at much lowercost than satellite telephony.

In a recent installation in an open-pit mine, a fixed wireless mesh nodewas placed at the administrativeoffice, and several relocatable wirelessmesh nodes with solar power weredeployed on trailers throughout theactive area of the mine. Mobile mesh

nodes on haulage trucks and loadersprovided communications for theautomated mining application in useon the vehicles. Because of third-generation radio intelligence, thenodes maintain communicationsthroughout the active area of the mineand can be easily relocated. OptionalGPS capability allows managers toinstantly locate any of the wirelessmesh nodes and its host vehicle on amap view of the mine. Additionalsafety voice and video applications

may also easily be deployed over thewireless mesh infrastructure.

The wireless mesh technology pro-vides the high performance, low delayand jitter, and mobility required forreliable communications in demandingmining environments. Best of all, net-works deployed to increase miner safe-ty may also boost productivity andvice-versa. As mining becomes moretechnical and automated, third-generation wireless mesh keeps themining enterprise seamlessly connect-ed from working face to office. ■

Byron Henderson is vice president, market-

ing for MeshDynamics, which serves cus-

tomers in many market areas: mining and

industrial sites, defense, transportation, pub-

lic safety and municipal networking. E-mail

comments to editor@RRMediaGroup.com.

The nodes wirelessly link miners at theworking face to the rest of the mine, aswell as to the office and managers outside the mine.