The system, which works alongside the UltraComm leaky feeder communication system, uses wireless readers and high power RFID tag units to provide personnel and/or asset location information on the surface of an underground mine or other facility. Tunnel Radio’s design allows for both voice communication and tracking to operate on a single cable. A ‘triple reader’ monitors three zones concurrently providing the continuous coverage as required by MSHA PPL P09-V-01. The system’s capture software provides for secure tag to server communications, personnel location viewable overlaid on a mine map, and detailed history reports. Through Tunnel Radio’s association with HSC Industrial and its distribution network, the system has already been successfully installed in at least 25 coal mines in West Virginia and Pennsylvania. According to Tom Hughes, president, HSC Industrial, the systems are receiving rave reviews from mine managers, safety personnel and miners alike.

Through its integrated network, the MineAx system determines the location of personnel by using receiver nodes in underground mine applications. All this is accomplished via the existing leaky feeder network, no additional cables are required. The wireless reader/radio unit collects RFID information as the tag passes within range of the reader antenna system; attaches time stamp and stores tag data; and when polled via the 2-way radio network wirelessly transfers the tag ID and location data to a capture computer on the surface for decoding and display. Three zones may be reported via a single 3-port reader unit.

Tag information/location data are shown based on actual tag read time, not computer time. Reader units may be located up to 200 ft from the radio network and still provide data connectivity. All collected data are secure.  The capture software is extensive and incorporates tabular and map import capabilities. In the mapping mode, personnel and equipment locations may be displayed through the use of a variety of user selected icons.

The reader/transceiver unit is part of a multi-component system of reader/ transceiver(s), RFID tag(s), head unit, PC and capture software. The RFID beacon transmitter or ‘Tag’ is MSHA approved (#23-A080005-0).

Tunnel Radio has been extensively testing the MineAx network in a number of active hard rock and coal mines, and has more than 20 permanent installations. It is designed to meet the requirements of the 2006 Miner Act and is MSHA Approved.

The MineAx network is designed from the ground up, as a personnel tracking system tailored specifically for the harsh mine environment. Tags are water submersible, sealed and very rugged. Readers are housed in a heavy aluminum water-resistant enclosure; and may be battery- or AC-powered. The triple reader was designed to be able to provide coverage in primary, secondary, and return air locations, as required by the MSHA PPL.

The high-power MineAx tag units allow consistent and reliable reads over greater distances, even from enclosed cab man-trips and pickups. Long range readers capture distant tags even during two-way radio traffic. Reader range is at least 100 to 150 ft each direction, or 200 to 300 ft of coverage per reader. Robust data transfer algorithm checksum ensures no captured tag data is lost.

One-read, one-posting design means that each RFID tag transmits a multiple-burst ID every few seconds. MineAx requires the capture of only one complete ID pulse to post to the surface computer. The readers store many hundreds of tags—if reader-to-surface connections are interrupted, no tag information is lost. The head unit stores data on a USB thumb drive. If the host computer or software is disabled, all history information is securely stored for convenient and secure retrieval.

The majority of permanent readers will be AC powered with battery backup (located in the reader).  The back-up battery can supply the reader for about three days. Readers that are near the working face can be powered by a lithium battery, which lasts approximately three months. Each reader reports battery voltage to the MineAx server, which notifies the dispatcher in the event of a low battery. A green ‘Online’ text box assures connectivity. Even with continuous operation, Tag batteries are estimated to last about two years. When any tag battery is low, the MineAx server notifies the dispatcher of which tag needs to be replaced.

The server-based software allows for remote monitoring and administration.  When connected to a TCP/IP network, this means the capture software may be viewed and modified from multiple (and remote) locations. Mapping software overlays the system existing mine maps, or as a tabular display.