Various devices have been tested with mine rescue teams involved in emergency response simulations at NIOSH’s Lake Lynn Laboratory and mine sites in smoke trials. The simulations are part of NIOSH’s emergency response and research program, which aims to enhance the safety and the effectiveness of mine rescue teams and fire brigades, but also to evaluate and prove technology that can be used during rescue, exploration, fire fighting, and escape.

Fire prevention engineer Ron Conti said many of the devices used in the simulations had not yet gained approval for use in underground mines, but NIOSH was working with the U.S. Mine Safety and Health Administration to make the technology permissible.

Chemical lightshapes (lightstick, lightdisc and lightrope) were employed for identifying areas and mapping out an escape route. Conti said the lightshapes were non-flammable and not an ignition source as well as weatherproof, maintenance free and non-toxic. The brightest lightstick has a duration of 5-min; the least brightest, 12-hours. Miners are encouraged to have a chemical lightstick on their person.

Conti said a lightstick served a two-fold purpose. Firstly, if a cap lamp malfunctioned, an instant source of light would be available and secondly, a lightstick may be used as an aid to travel through smoke.

During the simulations, the participants turned off their cap lamp and held a green lightstick out in front of them, about waist high.

In a similar vein, strobe lights were also used to map out escape routes. Strobe lights were suspended from the roof in the center of the mine passageways at decision points (approximately 6.5-ft from the floor).

By interfacing an audible sound with the strobe lights, miners have a reference point to follow during their travel in smoke-filled entries. Ideally, underground sensors would detect the gases and smoke in the passageways during a fire.

By coupling the sensor data with a computer, the best escape routes could be determined and the appropriate strobe lights could be remotely activated by a wireless, through the earth signalling system.

Conti said personnel involved in simulations had found laser pointers to be valuable for negotiating travel through smoke and for the identification of rescue team members.

A green laser was mounted on the captains cap lamp and a red laser was mounted on the tail person cap lamp, allowing team members to better align themselves along the lifeline and identify the location of the captain and tailperson.

“Lasers are useful for anyone travelling through smoke and are much more effective than a cap lamp because of the ‘white-out’ effect caused by the cap lamp mounted on the helmet,” said Conti. When the light beam from the laser strikes an obstacle, such as a mine rib or mine door, a spot is clearly visible.

The NIOSH developed lighted team lifeline is also proving itself to be invaluable during rescue simulations. Certain lengths of the lifeline are colour coded, allowing team members to easily find their position in darkness and smoke. It also aids in alleviating tripping and falling problems.

“Link lines provide a fixed point for team members during exploration and recovery. The captain and tailperson are attached to both ends of the 28-ft length of line and the other three members have the freedom of movement along the line and then return to their fixed colour positions when necessary,” he said.

Conti said the lighted team lifeline (link line) made tasks such as constructing roof supports and ventilation controls easier, because team members have the flexibility of sliding along the lifeline between the captain and tailperson.

NIOSH has also developed the inflatable feed tube partition and the positive-pressure inflatable escape device or airlock. The inflatable partition rapidly blocks large openings and provides a feed-tube for high expansion foam generators.

The inflatable airlock isolates smoke-filled entries from fresh air. This rapidly deployed device, with its “pass-through” feature, can be inflated with blowers, compressed air or inert gas.

“We have used it during simulations with rescue teams as an inflatable airlock. The team enters the mine and uses the airlock to establish a fresh airbase. As the team continues to explore the passageways, the bag can be moved further into the mine.”

For vision enhancement in a smoke-filled mine environment, NIOSH is evaluating thermal imaging cameras.

“The camera is an invaluable tool for emergency responders and can save lives. It doesn’t matter how thick the smoke is, you can easily locate missing or unconscious persons,” said Conti.

The cameras, which cost between US$8,000 to US$18,000, can also be used as a fire prevention tool says Conti. “You can examine fire-prone areas such as conveyor belt lines and drives and see hot bearings or elevated temperatures due to frictional heating’s or electrical cable faults before a fire develops. By doing this you can eliminate a lot of fire problems.”