Published in the March 2006 American Longwall Magazine

It was accomplished at NIOSH’s Pittsburgh Research Laboratory mine near Pittsburgh, Pennsylvania, and the testing included several calls made to various endpoints in different states – from a depth of 1000ft – patched at the mine portal to a POTS line, or Plain Old Telephone System.

According to Hannah Engineering representative Dewayne Hannah, the development of the system includes both a wireless mesh communication system and wireless tracking system. The development of these systems was under way well before the Sago mine explosion of 2006 that contributed to the passing of the MINER Act in June of last year.

Formally, the system will be deployed as Hannah Engineering’s Wireless Integrated Technology Systems (WITS), and will include three interrelating but vital functions to mine communication and miner safety.

The first segment was produced by Pennsylvania firm Rajant Corporation, a technology known as BreadCrumbs that has been put to the test through deployments in Iraq and in the aftermath of Hurricane Katrina in September 2005.

Each BreadCrumb is a wireless access point that, when dropped in any pattern, will form its own mesh, or “checkerboard”, communication web. Each point has its own power source.

Unlike wire communication, such as a leaky feeder system, Hannah noted that when one point is destroyed, the remainder of the web will go into a self-healing mode to recreate non-interrupted links.

The communications that can be completed with the system, according to Hannah and Rajant, are instant and interface with VoIP phones within the mine.

Peer-to-peer communication is also available and to switch back and forth between that mode and BreadCrumb or Normal mode is quick and simple, Hannah said, adding that such a feature could replace mine location reporting phones. The nodes are also outfitted with an Ethernet center and can be alarm notifiers.

“Safety within the mines relies on having the most current communication solutions,” Rajant chairman Bob Schena said in a January statement. “The combined solution from Rajant, Hannah Engineering and Sanmina-SCI offers a breakthrough on how miners can communicate, and be tracked, within a mine.”

Rajant has also developed the second segment, BCAdmin, a network monitoring device that works in conjunction with the BreadCrumbs that, because they were hand deployed, can serve as a tracking device to follow the movements of a miner. Hannah said the software can sense phone connections as well.

The third and final segment was the brainchild of Sanmina-SCI’s Defense and Aerospace Systems division, a 1400-person Alabama operation. REDI-COMM serves as the interface for the BreadCrumbs, linking communication devices such as emergency radio systems, POTS lines and other networks together.

Currently, Sanmina-SCI and Hannah Engineering are putting the finishing touches on the WITS MP1, a ruggedized, waterproof phone system that will be specifically configured for use in underground mines. Each unit, which will be certified, will be able to be pre-programmed with the specific phone numbers as required at each mine.

The companies have already developed and are continuing to work on a jawbone microphone that can be connected to the phone for emergency situations that may restrict an individual from being able to speak clearly, such as with the use of a self-contained self-rescuer. Hannah said the microphone can be put on the phone and placed behind the neck to maximize safety when it is donned.

To provide redundancy in the system, Hannah outlined plans to have tracking tags on the miners themselves in addition to tracking through the deployment of BreadCrumbs and BCAdmin’s associated tracking ability.

Under normal circumstances, he explained, the nodes can be powered in one of two ways, one being via an AC/DC power inverter – an item that the company said is already permissible. When AC power is absent, the second option is a 20-day IS battery that can be used to power it. Also, in the event of power failure, an onboard IS battery will provide 53 hours of emergency power.

Aside from the obvious benefits of such a system, Hannah outlined that there is also the ability to connect to satellite and online phone services if no traditional land communication service is available.

The BreadCrumbs and REDI-COMM/Dispatcher units are available now and are nearing submission for MSHA approval. Hannah said the first version of the phone, or “proof of concept”, was scheduled to be available in February 2007 and full production capacity of the WITS MP1 phone is expected in July.

The key to the product is its comprehensive nature, he noted. “By delivering a complete system, coal mines can more quickly meet the new regulations, improve safety, and have better response mechanisms in the case of an emergency. We are looking forward to commercial deployment of the solution and to making our mines safer.”