Aug 1, 2008 12:00 PM, By Merrill Douglas

Radios promote safety, efficiency in underground mines

When Utah's Crandall Canyon Mine suffered a collapse in August 2007, rescuers raced to reach six miners trapped inside — and Tunnel Radio of America worked along with them. A communications systems integrator, Tunnel Radio quickly built the infrastructure for an underground radio system. Workers used it as they cleared a path through the rubble into the interior.

“That way, our rescuers had communications as they were moving into the mine,” said Terry Stringham, an RF technician with Windriver Wireless, a Kenwood USA dealer in Roosevelt, Utah, that works with Tunnel Radio. Windriver sent down a dozen handheld radios, providing communications between the people operating the heavy machinery and others bringing in equipment behind them.

Unfortunately, that rescue effort ended in tragedy: a second collapse killed three rescue workers and injured six others.

The Miner Act of 2006 requires that each underground mine in the U.S. implement two separate, redundant systems to provide communications in the event of an accident. In response, vendors have been offering, and the Mine Safety Health Administration (MSHA) has been testing, various systems based on newer technologies such as mesh networking and voice-over-IP (VoIP) telephony.

But two-way land mobile radios also are an option, and they're already playing many important roles in underground mines, both for everyday operations and for emergencies. Surprisingly, although LMRs are common tools in many heavy industries, not all mines use them.

“Around this area, I really don't know anyone other than us that does use them,” said Jay Toney, superintendent of the Sunrise Coal Company in Carlisle, Ind. Sunrise has employed radios underground for about 10 years.

Mine radios are gaining ground, however. For example, Lauttamus Communications in Wierton, W. Va., is providing more than 1300 Kenwood radios to Console Energy for its mines, said Paul Lauttamus, the radio dealer's vice president. “We're, right now, at the ground floor of this. It's a market that's evolving as we speak,” he said.

One reason radios haven't become ubiquitous in mines is that an underground tunnel system creates a hostile environment for radio signals. “It becomes like an RF tomb,” said Joe Watts, land mobile radio product manager for Kenwood USA. “There's a lot of energy absorption, reflection, cancellation. The deeper the radio waves go, the more attenuated they become.”

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