environments. The LiteLine furnishes moderate ambient
light level everywhere it’s deployed. Rather than a limited
“point-and-beam” light source, it is a continuous strand of
omni-directional light in 30 to 90-m lengths. It is
lightweight, flexible, easy to deploy and requires 120 VAC
power.

A few underground mines use a continuous lifeline for
escape purposes. This lifeline or rope would most likely be
secured to the rib of the mine starting at the working section
and leading to the exiting portal. Depending on the
configuration of the mine, the lifeline could be many
kilometers in length. One manufacturer developed a
directional lifeline. It consists of standard spools containing
91-m of 0.64-cm polypropylene rope with directional (cone-
shaped) orange indicators installed at every 23-m interval.
Due to the complexity of mine entries that contain crosscuts,
mandoors, overcasts, etc., it is suggested that two directional
indicators be mounted together on the lifeline approximately
2 to 3-m from a mandoor, etc. This procedure would alert
personnel escaping in smoke-filled entries that an obstacle of
some sort is nearby.

Fire fighting and similar emergency response activities
often impair vision due to dense smoke or darkness. Vision
enhancement in such circumstances is a profound benefit for
completing the assigned task. Infrared (IR) thermal imaging
enhances the user's vision when visible light is inadequate.
Thermal imaging both restores vision and also provides
significant additional information to the user that would
otherwise be not possible to obtain. Figure 6 shows a mine
rescue team member with a thermal imaging camera. This
technology increases the responder's understanding of the
environment, thus enhancing safety and the ability to
accomplish the task. The first documented civilian life saved
with thermal imaging technology occurred during a 1988 fire
in New York City.

Recent improvements in the sensitivity and resolution of
uncooled IR imaging sensors have provided the major

Figure 6.-Rescue team member wearing the FireFLIR
thermal imaging camera

enabling technology for the development of a practical helmet-
mounted IR vision system Miller''. In 1995, Cairns &
Brother Inc. introduced the first commercially available hands-
free helmet-mounted IR imaging systems. Firefighters can use
the Cairns IRIS to see through dense smoke and darkness in
structural fires allowing "size-up" of the situation to be faster
and more effective. The system processes the signal and
displays a black and white image that shows the hottest areas as
white, the coldest as black and the temperatures between as
varying shades of gray. It can detect 0.3 °C differences in
temperatures. The sensor is a specially coated 15-mm
Germanium lens that filters out everything except 8 to 14-
micron infrared radiation. The helmet-mounted IR imaging
system weighs 4.8 kg. A rechargeable nickel cadmium battery
pack provides 30-min of continuous, uninterrupted use at
ambient temperature.

The first demonstration of the Cairns IRIS in an
underground mine was conducted at LLL on February 8, 1996.
The capabilities of the hands-free thermal imaging camera in
the smoke-filled mine passageways suggested that it indeed had
merit for reducing the time required for mine rescue
exploration. However, the inmine simulations suggested that
new protocols should be developed when mine rescue teams
explore with these IR devices, because the team member with
the thermal imaging camera can _ travel smoke-filled entries
much more rapidly than other team members. A drawback of
the Cairns IRIS is the weight of the helmet-mounted system;
the system cannot easily be passed on to other team members
and could not be used in low coal mine seams. Cairns IRIS
recently introduced the Cairns-Viper, a hand-held thermal
imager. It offers superior image quality, and the innovative,
180- degree-rotating display provides comfortable viewing
from any position. It enables the user to see from 0.9-m to
infinity.

The Agema 550 System is a high-performance handheld IR
camera. It has digital voice recordings, color images, and
storage capabilities. The spectral range is 3.6 to 5.0-microns
and weighs 2 kg. It can easily be passed on to other team
members or a small display can be added to the camera for all
team members to view. The major advantage is that the image,
shown in figure 7, can be downloaded to a computer for
analysis or interfaced directly to a monitor for debriefing
members at the command center. IR cameras may also be used
for preventive measures; such as to fire boss underground areas
prone to fires, like belt drives and power centers.

Figure 7.-A thermal image of a conveyor belt
structure


Mine Safety, J. Holt, Consol Inc., and L. Derick and B.
Krump, Twentymile Coal Company for their contributions to
this effort.

REFERENCES

1. CONTI, R.S., CHASKO, L.L., and STOWINSKY, L.D.
Mine rescue training simulations and technology.
Proceedings 5” International Emergency Management
Society Conference, The George Washington University,
Washington, DC, May 19-22, 1998, pp. 453-464.

2. CONTI, R.S., CHASKO, L.L., and COOL, J. An
overview of technology and training simulations for mine
Tescue teams. Proceedings Twenty-Eight International
Conference on Safety in Mines Research Institutes,
Sinaia, Romania, June 7-11,1999, vol 2, pp. 521-538.

3. CONTI, R.S. and WEISS, E.S. Inflatable devices for
combating mine fires. Proceedings 4" International
Conference on Safety and Health, in the Global Mining
Industry (Minesafe International 1998), Sun City,
Republic of South Africa, September 28 - October 2,
1998, pp. 388-393.

4. KENNEDY, W.D., BAYNE M.L., and SANCHEZ,
J.G. The use of inflatable barriers and jet fans for the
control of smoke in the washington subway. Elsevier
Science Publishers Ltd. England, Aerodynamics and
Ventilation of Vehicle Tunnels, 1991, pp. 433-464.

5. WEISS, E.S., CONTI, R.S., BAZALA, E.M., and
PRO, R.W. Inflatable devices for use in combating
mine fires. Pittsburgh, PA: U.S. Department of the
Interior, 1996, USBM, RI 9614.

6. MATTES, R.H, BACHO, A., and WADE, L.V.

Lake Lynn Laboratory: construction, physical
description, and capability. Pittsburgh, PA: U.S.
Department of the Interior, 1983, USBM, IC 8911.

7. CONTI, R.S. and YEWEN, R.G. Evaluation of a
signaling warning system for underground mines.
Pittsburgh, PA: 1997, NIOSH RI 9641.

8. DOBROSKI, H. JR. and STOLARCZYK L.G.
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mine rescue. In: postdisaster survival and rescue
research. Proceedings: Pittsburgh, PA: U.S.
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9. ZAMEL, G.I. A breakthrough in underground

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CONTI, R.S. and CHASKO, L.L. Technologies for
today’s mine emergency responders. Proceedings 7
International Emergency Management Society
Conference, Orlando, Fl, 2000, pp. 105-121.
MILLER, J.J. Evolution of helmet-mounted sensor
systems. Sensors, vol. 14, No. 11, Nov. 1997, pp. 42-
45

Pittsburgh Post-Gazette. Cutting through the smoke.
Spice, B., vol. 71, No. 1998, February 14, 1998,

pp. A-I & A-8.

CONTI, R.S. Fire-fighting resources and fire
preparedness for underground coal mines. Pittsburgh,
PA: U.S. Department of the Interior, 1994, USBM, IC
9410.

HAVENER, R.E. Application of high-expansion foam
to fight underground mine fires. Coal Age, v. 80, No.
2, Feb. 1975, pp. 144-147.

NAGY, J. MURPHY, E.M. and MITCHELL, D.W.
Controlling mine fires with high-expansion foam.
Pittsburgh, PA: U.S. Department of the Interior, 1960,
USBM, RI 5632.

CONTI, R.S. AND LAZZARA, C.P. Inflatable
partition for fighting mine fires. U.S. Patent No.
5,469,920, November 2, 1995.

CONTI, R.S. Inflatable partitions for high expansion
foam generators. Mining Engineering, vol. 47, No. 6,
June 1995, pp. 561-566.

Mitchell, D. W. Mine fires: prevention, detection,
fighting. Maclean Hunter Publishing Co., 1996.
CONTI, R.S., CHASKO L.L., and PRO R.W.
Combating mine fires with the aid of inflatable devices.
Proceedings 2“ International Conference on Fire
Research and Engineering, National Institute of
Standards and Technology, Gaithersburg, MD, August
3-8, 1997, pp. 441-449.

BIRD, M., DAVIS, W., DOUGLAS, G.A., GIBSON,
G.A., MACKENZIE-WOOD, P., TAGUE, I.,
TONEGATO, S., TROTMAN, B., and WALTER, M.
Emergency preparedness and mines rescue. Mines
Rescue Board NSW, Jan. 1999, 453 pp.

BALDWIN, G. L. Inflatable portable refuge structure.
U.S. Patent No. 5,537,784, July 23, 1996.


from any point along the guide wire. It has a range of 8-Km
and the guide wire could be deployed from the fresh air base
(FAB) to the surface command center, so that everyone can
hear the whole story simultaneously. This would eliminate
repeating messages and everyone would be ready for
decision-making.

Experiments with mine rescue teams indicate exceptional
quality of speech when one handset was used at distances of
300-m. However, when three handsets were used within the
8.5-m length of a rescue team, quality and reception
degraded. The small size guide wire easily tangled, frayed,
and broke when used as intended. The same occurred when
the guide wire was taped to the main team lifeline. For all
practical purposes, the small guide wire cannot replace the
present lifeline for U.S. coal mine rescue teams. Perhaps a
guide wire with a higher tensile strength like stainless steel or
other material could be used. Additional research is being
conducted to see if the wiring from the current sound
powered communication/lifeline system can be used for this
system. Other emergency rescue personnel can still use the
present system in its current design.

Inflatable Devices for Fire Suppression and Personnel
Escape

When mine fires can no longer be fought directly due to heat,
smoke, or hazardous roof conditions, high expansion foam
(HEF) may be one way to remotely quench the fire. The
firefighters and HEF generator can be located away from the
immediate vicinity of the fire at a less hazardous underground
location. The HEF is a convenient means of conveying water
to a fire Conti’, Havener'*. It quenches or extinguishes a
fire by diluting the oxygen concentration through the
production of steam, blocking the air currents to the fire, and
blocking the radiant energy from the fuel to other
combustibles Nagy’.

To effectively use the foam method for remotely fighting
fires in underground mine entries, it is often necessary to
construct, at some distance from the fire site, a partition or
stopping in fresh air to separate the foam generator and its
operators from the smoke and toxic fire products. If this is
not done, the HEF could flow back over the foam generator,
rendering the fire attack futile. This problem is especially
acute when the fire is found uphill in a sloping entry.
Concrete block, wood, plastic sheeting, mine brattice cloth,
or similar materials have been used for such partitions.
Often, mine entries have irregular dimensions to which the
partition must conform to avoid leakage around the
periphery. Construction of such partitions can be a time-
consuming process. After the partition is constructed, a hole
must be cut through it to allow passage of the high expansion
foam from the foam generator to the fire site. During an
underground training simulation for mine rescue teams and
fire brigades in an operating coal mine, it required
77 minutes to construct a partition from wood, metal and
brattice curtain, and start the foam propagating up the mine
entry.

To address the drawbacks of constructing a partition for
HEF generators, the inflatable feed-tube partition (IFTP)
Conti'*!” was developed. The IFTP is a lightweight,
inflatable rectangular bag. The device can rapidly block
large openings (within 15-min), such as those in underground

mines, and simultaneously provide a feed-tube for high
expansion foam. This allows firefighting foam to freely flow
to the fire site and control or extinguish the fire.

The portable IFTP can be easily transported to a mine
passageway leading to a fire area and then be inflated by a
permissible fan/air blower, a compressed air line or an inert gas
source (air or inert gas sources must be kept on to compensate
for leakage). The IFTP is made from a water and heat
resistant, lightweight fabric (0.076-mm thick), such as
chemically treated, rip-stop nylon. The IFTP could also be
fabricated from a material such as Mylar or other fire-resistant
materials. The shape and size of the IFTP depend on the
passageway dimensions in which it may be used. For example,
for a mine entry 2.1-m-high by 5.8-m-wide, the IFTP would
take the shape of a slightly oversized rectangular bag
approximately 2.6-m-high by 6.1-m-wide and 3.1-m-long.
Experiments in the Lake Lynn Experimental Mine showed that
a 2,800-L/s diesel-powered (fixed driving force), high-
expansion foam generator with the IFTP could push a foam
plug 245-m through an entry 2. 1-m high by 5.8-wide with 24.3
percent rise in elevation, before the foam generator failed to
push the foam plug further. Additional information on the use
of foam, partitions and other inerting methods can be found in
the following references Mitchell'*, Conti, Bird.

Another conceptual use of an inflatable bag is a positive-
pressure, inflatable walk-through escape device (IED), shown
in figure 9. This rapidly deployed device, with its "pass-
through” feature, allows extra time for personnel evacuation by
isolating a smoke-filled entry from fresh air. The IED would
be strategically placed in a mine entry, and then be either
manually or remotely deployed during a mine fire. Evacuating
miners would enter the IED from the smoke-filled entry and
exit into the fresh airside.

To better maintain inflation when the IED doorways are
opened, a third generation positive pressure, inflatable escape
device was fabricated and successfully evaluated in the Lake
Lynn Experimental Mine. The unit is a rectangular bag
constructed from a heat resistant lightweight fabric and is
inflated by two fans, one of which is connected to an integral
fabric tubing air distribution system. The IED can also be
inflated by compressed air. Large C-shaped zippered doorways

iis i

ure 9,-Rescue team members entering the IED



A Flir System called FireFLIR, is used in conjunction
with SCBA's and is easily attached to the underside brim of
most standard firefighting helmets for hands-free operations.
It is a completely self-contained viewing apparatus with no
external cables or components to catch or impair movement.
The spectral range is 8 to 14-microns. The device weighs
less than 2 kg and images can be viewed in either black and
white or color. Advanced ‘optics and display offer natural
depth perception and orientation. It is also designed to view
either IR or visual viewing modes and is quickly and easily
handed off to other team members.

The Argus Thermal Imaging Camera (TIC) can also see
through smoke and darkness. It is ergonomically designed
for comfort and utility, is handheld, and has an angled
viewfinder. Moreover, the TIC accommodates a variety of
users’ positions from standing to lying prone. In low coal
exploration, the innovative design reduces potential neck
strain and, when used in a stooping position, helps to prevent
the back of the helmet from hitting the SCBA, which can
occur with the helmet-mounted version. It can easily be
passed on to other team members for viewing the thermal
image. Argus recently introduced the next generation camera
that features a remote wireless video transmission system.
During experimental tests at LLL, the video signal from the
camera was successful transmitted from inside a metal and
concrete block fire gallery to an outside remote receiver
station. The remote receiver, located 60-m away, was
positioned in the direct line of sight to the camera.
Command center or fresh air base personnel could use this
feature to better direct rescue efforts.

Seeing through infrared cameras is different than with
natural vision. IR images are thermal interpretations of
objects and those interpretations do not appear the same as
the objects appear when you look at them with the naked eye.
Itis imperative that personnel using these devices be properly
trained.

Communications

Communication is a major issue and concern of rescue teams.
Team members are often unable to hear other members, and
at times the communication signal to the fresh air base is also
faulty. This can be very frustrating to team members,
especially in high stress situations.

The sound powered communication/lifeline system,
developed in 1946 by the former U.S. Bureau of Mines, is
the most typical system in use today. Although this type of
system tends to be reliable, it does have problems. It
requires the use of large cable reels (304-m of cable) and the
communication usually gets scrambled as the electrical
contacts in the cable reel wear. Also, good electrical
connection to and along the lifeline cable is necessary. The
current practice is that the tailperson, who has the earphones
and microphone, talks to the fresh air base.

To address the communication concerns of mine rescue
teams, the voiceducer two-way communication device was
evaluated at LLL. The voiceducer, combined with a two-
way radio, provides hands free two-way communications
from a small device worn in the ear. Although it looks like
an ordinary earphone, the earpiece contains both an
accelerometer microphone and miniature receiver
component. The ear microphone detects speech-induced

bone vibrations via direct contact with the ear canal wall. The
miniature earpiece leaves the hands free and face’ unobscured
when worn by rescue personnel with breathing apparatus.
When in high ambient noise, suitable earmuffs can be worn.
The user consequently is afforded a much greater degree of
freedom than has previously been possible with two-way radios.

At LLL, a radiating transmission line, base station and
Tepeater system along with two-way radios are used for daily
communications between employees. The in-mine transmission
line leaks a controlled amount of radio frequency energy over
its full length so that two-way radio communication can be
maintained for a considerable distance through the mine
passageways and to the surface. Experiments with rescue
teams at LLL indicated this system and the voiceducer showed
potential. Both the captain and tailperson could communicate
with the fresh air base. However, the earpiece slipped out of
the ear canal at times and background noise was also a
problem.

Additional research efforts could include inserting a wire
antenna into the main lifeline communication system that
extends from the team to the fresh air base. The latter example
could serve as a backup communications system. During
exploration, team members would have the antenna with them
and can use the voiceducer. By having several channels on the
radios, communications between team members or the fresh air
base can be controlled.

Another new concept that may be used by rescue teams is
the head-contact microphone Pittsburgh Post-Gazette”. It is a
hands-free radio microphone that can either be strapped onto
the forehead or incorporated into a helmet headband. A rescue
member need not speak into this microphone; it gathers sounds
from vibrations transmitted through the skull and works
whether the rescue member is wearing an SCBA or not. The
microphone picks up little background noise, so rescue
members need not shout. Ear speakers are suspended on the
helmet and a gloved hand can easily activate the system by
touching a sensitive on/off switch.

The m-Comm communications system was developed in the
United Kingdom was also evaluated with mine rescue teams at
LLL. The m-Comm system, shown in figure 8, is intrinsically
safe and designed specifically for confined space and rescue
applications. This system employs advanced low frequency
(single wire) guide propagation techniques to achieve flexibility
and dependability. The system consists of three handsets, a
portable base unit, a dispenser reel holder, and lightweight
guide wire that are available in various sizes. The guide wire
is payed out on entering a confined space. A button on the clip-
on handset is pressed to talk. The handsets receive and transmit

Figure 8.-Diagram of the m-Comm communication
system


dealing with the sudden loss in communications to the surface
command center, FAB, exploring team and backup team due
to a massive roof fall caused by an explosion. During the
simulations, all problem tasks completed by the teams are
tracked. At the end of each simulation, all participants
answered a series of questions. These included
demographics; usefulness of the fresh air base briefing; how
the team members, FAB and command center personnel
made decisions; anxiety levels and physical demands of the
rescue operation; and any issues that may arise during the
exercise. The rescue teams, command center and observers
as a whole was then debriefed. This open forum offers an
excellent opportunity for all participants to engage in some
lively conversation about the simulation. For example, how
was the strategy developed for exploring the entries, and how
good was the communication between team members, the
fresh air base and surface command center.

During the MERD exercises, the team members voiced
several concerns regarding the command center’s perceptions
about solving tasks in smoky passageways. While personnel
in command centers are generally very knowledgeable in
their own areas, a key element to remember is that
inexperienced command center personnel do not fully
understand the basic principals of the mine environment, how
the team explores in smoke and communicates with the fresh
air base.

Several recommendations are offered for personnel who
maybe stationed in command centers. Command center
personnel should spend some time underground at the fresh
air base during the MERD exercises. They need to tag along
with the rescue team and observe how teams explore and
complete tasks. These personnel need to evaluate teams in
smoke-filled passageways from an observation area; for
example, how teams travel from point A to point B, set-up
roof support or incorporate ventilation controls. Observers
may utilize thermal imaging cameras to do this. Their
abilities to participate in or lead the command center would
be enhanced after they complete these basic underground

requirements. They need to be opened-minded for input ~

from others and flexible in decisions when circumstances
change.

Team members, company personnel and Government
officials all agreed that the simulations are extremely
beneficial. The program offers a unique opportunity to
develop and conduct realistic training simulations for mine
rescue teams and command centers at Lake Lynn Laboratory
and operating mines and evaluate technology for mine rescue
operations.

CONCLUSIONS

This cooperative effort between NIOSH, state agencies, and
mining companies offered an excellent opportunity to provide
Tealistic training to mine rescue teams, fire brigades, first
responders, and miners in general, and evaluate new and
existing technology that may be used for underground mine
emergencies. For example, rescue teams have identified
green as the most visible colored lightshape in both white and
black smoke. These teams have now added chemical
lightshapes to their cache of rescue team supplies.

Strobe lights were useful for mapping out an escape route
for evacuating miners. Activation of the strobe lights by the
wireless, through the earth signaling system was successful.
Additional research would be required to evaluate the
feasibility of using these devices in larger mines and to
incorporate audio output with each strobe light unit.

During smoke training exercises, red and green laser
pointers were effectively used to negotiate travel through
smoke-filled passageways. The green laser pointer was the
most visible color in white smoke.

By using the new-lighted team lifeline, team members have
freedom of movement between the captain and tail-person.
They can visually see the rope, their own position and are more
flexible to do activities such as carrying supplies, erecting
stoppings and constructing roof supports. The team lifeline also
alleviates tripping and falling problems. The electro
luminescent fiber of the light vest allows team members and
personne! working in darkness, smoky conditions or around
moving machinery in low light areas to be seen more easily.
Several mines are considering the use of light vests for
personnel working around moving machinery.

Escape from complex underground passageways could be
improved by using a continuous lifeline. Utilizing directional
cones and double cones on the lifeline would not only lead
personnel escaping in smoke-filled entries in the right direction,
but also alert them that an obstacle of some sort is nearby.

The thermal imaging cameras have merit for mine rescue
exploration and recovery in the smoke-filled mine passageways.
However, the simulations suggested that new protocols need to
be developed when mine rescue teams explore with these IR
devices, because the team member with the thermal imaging
camera can travel smoke-filled entries much more rapidly than
other team members.

Both inflatable devices have shown merit in providing a
relatively rapid method for isolation of a mine fire and use with
a foam generator for fire suppression, or for personnel escape
and rescue. The inflatable partition can rapidly block large
openings, such as those in underground mines, and
simultaneously provide a feed-tube for high expansion foam.
‘The inflatable escape device could be used as an airlock system
during exploration by mine rescue teams and could be rapidly
advanced as mine recovery operations progressed.

The m-Comm communications system shows merit.
Utilizing the voiceducer, with the present radiating transmission
line at Lake Lynn Laboratory, has shown potential for
improved wireless communications for mine rescue teams.
Additional research is required to incorporate the antenna into
the main lifeline. These technological advancements can.
improve the state of readiness for rescue personnel and increase
the chances of survival for personnel escaping from
underground emergencies.

Since the onset of rescue team training simulations and
MERD exercises at Lake Lynn Laboratory and operating
mines, some rescue teams, who trained in smoke for the first
time, were so confused that they gave up and had to be rescued.
Several team members have decided that rescue work was not
for them and quit the team. During another exercise in a low
coal, seam height 0.8-m, another member not only quit the
team but also the mining industry. Overall, the strengths of
the team and its members have improved since their initial
exercise. For example, confidence levels have increased, and
members are now working as a team, thinking through the
problem together. Teams are successfully accomplishing their
goals by replacing contest rules and placards with realistic
hands-on-training exercises.

ACKNOWLEDGMENTS

The author wishes to thank C.P. Lazzara, L.L. Chasko, F.A.
Karnack, D.D. Sellers, W. Slivensky, and W. Monaghan,
Pittsburgh Research Laboratory, J. Cool, D. Eppley,
J. Stanchek, and L. Stowinsky, Pennsylvania Bureau of Deep


Mine rescue and response

Ronald S. Conti
National Institute for Occupational Safety and Health (NIOSH) Pittsburgh, USA

This paper describes technology and training that has been identified for underground emergency
responders. Historically, underground mine rescue teams have only received training in the course
of actual emergencies, or in simulated mine environments, usually on the surface, with placards to
identify objects and hazards. Also, while U.S. Federal Regulations require all underground miners
to walk escapeways and conduct fire drills every 90 days in a smoke-free environment, this does
not fully prepare them for the conditions that will be encountered in real escape situations.
Therefore, it is extremely important that miners are provided with adequate technology and that
training simulations are conducted in a realistic manner.

A series of mine rescue training and mine emergency response development (MERD) exercises,
and in-mine smoke training was developed, conducted, and evaluated by state and company teams,
and by National Institute For Occupational Safety and Health (NIOSH) personnel. The training
exercises were held at NIOSH’s Lake Lynn Laboratory (LLL) and operating mines during the past
several years. This training resulted in improved technology and training for mine rescue teams,
fire brigades, first responders, and miners in general. For example, existing technologies were
identified to help responders during exploration and recovery operations. These included various
chemical light shapes, strobe lights, light vests, and laser pointers to identify team members. Most
of these devices may be used to mark underground areas and certain mine materials. Strobe lights
were used for mapping out escapeways and lasers were used to negotiate travel through smoke.
Thermal imaging systems allow rescue personnel to see in darkness and through dense smoke, and
allows the user to easily locate missing or trapped personnel and heated areas. A hands-free
communication system showed potential for enhanced communications between team members, the
fresh air base, and command center. A new team lighted-lifeline allows for flexibility in
movements of team members during routine tasks and allows them to easily find their fixed position
on the lifeline.

Of all the technology evaluated by underground personnel, laser lights and lifelines were most
beneficial in leading personnel to safety and out of the mine in smoke-filled passageways. A
positive-pressure inflatable escape device (IED)/airlock, was used to isolate the “hazardous”
environment from fresh air and allow rescue team members to traverse through. An inflatable feed-
tube partition that can rapidly block large openings such as underground passageways or tunnels and
simultaneously provide a feed-tube for high-expansion foam generators was also deployed during
the simulations. These technological advancements have improved the state of readiness for rescue
personnel and have increased the chances of survival for all personnel escaping from underground
emergencies.

Keywords: Emergency response, smoke training, mine rescue, response technology.

Introduction

Over the past several years, NIOSH's Pittsburgh Research
Laboratory (PRL) has conducted mine rescue training
simulations at its LLL near Fairchance, PA. Memorandums
of Understanding/ Agreement were established between
NIOSH and state agencies and several mining companies to
increase the operational effectiveness of their coal mine and
metal/nonmetal rescue teams and to evaluate new and
emerging technology Conti'?. These efforts have resulted in
improved disaster recovery training drills and the
development of new technology, such as new team lifelines
and inflatable devices for fire suppression anid personnel
escape Conti*, Kennedy‘, Weiss’. Existing technologies,
such as the use of chemical lightshapes, laser pointers and
strobe lights for identifying team members, and thermal
imaging equipment were evaluated. Current rescue protocols
and strategies were also assessed.

The LLL, formerly a limestone mine, is now a
multipurpose research facility used to conduct mining safety
and health research Mattes®. The new entry dimensions of
the underground mine range from 1.8 to 2.4-m high and from
5.3 to 6.3-m wide. The average dimensions are 2.1 and 5.8-
m, for an average cross-sectional area of 12-m’. The
underground configuration of the new entries covers
approximately 95-km?, with an overburden ranging from 50
to 100-m. The unique nature of the facility allows it to be
readily adapted for elaborate mine rescue team simulations in
smoke-filled entries.

Technology for escape and emergency responders
Emergency warning systems

It is imperative during an underground emergency that all
personnel, no matter where their location is, can be notified


on both sides of the IED allow easy entry and exit. Because
the bag is under positive pressure, it is impervious to outside
contaminants, such as smoke, if the air intake remains in
fresh air. During a mine fire, the IED would be rapidly
deployed to temporarily isolate a smoke-filled entry from
fresh air. If the inflating air was clean compressed air, the
bag could be used as a temporary shelter Baldwin”. The use
of a fan for inflation, however, would require that the fan
remain in fresh air or that filters be installed-on the fan to
cleanse the mine air of any contaminants. Mine rescue teams
could also use the IED as an airlock system during rescue
and recovery operations and it could be rapidly advanced as
mine recovery progressed. For this application, an inert gas
source could be used to inflate the IED if necessary. The
performance of the third generation IED was assessed during
mine rescue team training simulations conducted in the Lake
Lynn Experimental Mine. The IED was deployed in 5 to 10
minutes and isolated a smoke-filled passageway from the
fresh air base. Fully equipped five to seven member mine
rescue teams can enter or exit the IED without deflating the
unit. The IED has been successfully demonstrated at an
Open Industry Briefing on Mine Fire Preparedness held at
Lake Lynn Laboratory and an operating coal mine. This
device successfully isolated smoke-filled entries from fresh
air, and mine personnel effectively passed through the device
to the fresh air base or back into the smoke-filled entries.

UNDERGROUND SMOKE TRAINING EXERCISE

One hundred twenty-seven miners participated in a smoke
training exercise in a Western underground coal mine. The
average age of the participant was 37 years and average
number of mining experience years was 12. Miners in
groups of five traversed more than 300-m of mine
passageways filled with nontoxic smoke. Visibility ranged
from 0.5 to 3-m. One objective of the exercise was to
evaluate technology that could be used for escape purposes,
while giving the miners an opportunity to travel through
smoke-filled entries at their mine. The various devices were
mounted on the roof in the center of the entry, placed on the
floor or secured to the rib. Of all the devices (chemical light
shapes, strobe lights, laser lights, light vests, cap lamp,
reflective materials, thermal camera, lifeline, other)
evaluated in the nontoxic smoke, green was the most visible
color seen by most of the miners.

Figure 10 illustrates the responses of the miners for the
two most beneficial devices for identifying other people in
smoky passageways. The two devices chosen by the miners
Participating in the study were the light vest and lasers.
These miners also felt that the lasers and lifelines, responses
shown in figure 11, were most beneficial in leading you to
safety and/or out of the mine. Some of the miners were
concerned about the durability of lifelines during fires,
explosions, and roof falls. When asked about their views on
thermal imaging cameras or see-through-smoke devices, they
felt that this technology would not apply to escape. This was
mainly due to the cost of thermal imaging cameras.
However, they realized the importance of using this
technology for rescue and recovery operations and felt that
every mine rescue team or fire brigade should have access to
one. Fifty-six percent of the miners that participated in the
training reported that they have traveled through smoke at

some time in their mining career.

TRAINING SIMULATIONS MODULES FOR MINE
RESCUE TEAMS

During the simulations conducted in the LLL Experimental
Mine, rescue team members donned self-contained breathing
apparatuses and generally traversed more than 305-m of mine
passageways filled with nontoxic smoke. Visibility is
controlled and usually ranges from 0.3 to 0.5-m. The IED is
used by rescue team members to enter the "smoke-filled”
passageways from a fresh air base. Depending on the scenario
and objectives, the mine environment can be modified. For
example, in one area of the mine, a kerosene heater was used
to simulate a fire and reduce the oxygen concentration to 18
percent. This area has also been heated so that the temperature
is more than 38°C. In another area, a 1.5 percent methane
zone was established. Handheld sensors carried by the rescue
team members alarmed when they entered these areas, alerting
them to the “hazardous” condition.

Objectives of the mine rescue team simulations and MERD
exercises focused on fire fighting and ventilation techniques;
moving the fresh air base; confined space rescue; using thermal
imaging cameras; a backup team rescuing the exploration team;
rescuing and controlling a hysterical miner lost in smoke; and

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Figure 11.-Most beneficial devices for leading personnel
to safety and out of the mine in smoke


beam from a laser pointer (laser diode technology) was
visible to 10-m from the laser. The concept of laser pointers
was successful in experiments at the LLL and an operating
mine. Additional research is needed to evaluate the
feasibility of using a higher power laser to identify escape
routes in smoke-filled underground passageways and in
surface structures where community firefighters have
become disoriented or lost.

Everyone realizes the problem encountered while driving
an automobile in foggy conditions at night with high beam
headlights on. The same problem is experienced in smoke-
filled passageways both by miners attempting to escape and
also by rescue personnel. During several training
simulations in nontoxic smoke, a colored lens filter was
placed over the cap lamps of 121 miners in an attempt to
reduce the glare from the white light reflecting off the
smoke particles. The color filters that were evaluated
included green, blue, orange, and red. Green was the most
visible color seen by 38 percent of the miners. Seventy-one
percent of the miners felt the lens filters were useful in
reducing the glare from the white light and beneficial in
traveling through smoke. It has also been suggested that a
miner's caplamp can be taken off the helmet and held about
waist high to negotiate travel through smoke.

When emergency personnel are searching for missing
personnel or exploring a hazardous smoke-filled
environment in underground mines, rescue team members are
attached to a team lifeline or linkline. This team lifeline is
then connected to the main communication/lifeline that
extends from the area that needs to be explored to the fresh
air base. Usually, five team members are fixed along an
8.5-m length of rope at various distances between the
captain (lead person) and tail-person. Team members have
reported that if one person would trip and fall, other team
members would be pulled down with the falling team
member. If the rope became entangled around obstacles,
finding it was difficult.

These concerns were solved by the development of a
lighted team lifeline, shown in figure 4. Four different
colored flexible light wires (Live Wire technology, 0.5-mm
copper wire coated with semiconductor material) connected
in series, pass through a 0.6.4-mm diameter hollow-single
braided polypropylene rope (336 kg tensile strength). The
light wire extends 0-2.1 m (blue), 2.1-4.3 m (orange), 4.3 -
6.4 m (green), and 6.4 - 8.5 m (red), respectively, from the
captain’s position toward the tailperson’s position and has
360-degree visibility. The light wire is battery powered and
will last a minimum of 4-hrs. The entire length of the
braided rope is sheathed with clear polyvinyl chloride tubing.
Double-locking snaps and D-shaped carabineers are
attached to both ends of the rope for the captain and
tailperson, with three moveable snaps and carabineers in-
between both ends for the remaining team members. Team
members attach the carabineers to their mine belt and have
freedom of movement to slide between the captain and tail-
person, providing flexibility of motion to do activities such as
carry supplies, erect temporary ventilation controls and
construct roof supports. This also alleviates tripping and
falling problems. The different colored light wires allow the
team members to easily find their usual position along the
lifeline when exploring in darkness and smoke-filled
passageways.

Figure 5 illustrates mine rescue team members attached
to an earlier version of a high-visibility team lifeline
Conti’. In this prototype, a high-visibility rope with
filaments made of reflective material braided directly into

the sheath is used. The reflective filaments, based on glass-
bead technology, generate a return more than 1,000 times
brighter than plain, white rope. Team members attach to the
line with the carabineers as previously described. This
lifeline requires some light so that the reflective material can
be seen.

Another product is LiteLine 360. The lighted line offers
an illuminated path to safety for rescue personnel or
firefighters working in darkness or smoke-filled

Figure 4.—Lighted team lifeline

Figure 5.-Rescue team members attached to the high-
visibility team lifeline


length and current consumption is as low as 0.3 mA/m.
Two AA batteries power the vest for over 24-hrs. The light
vests were modified with Velcro straps to wrap around a
mine rescue member, including their SCBA, for 360 degree
lity. Team members felt that it was much easier to see
other team members who were wearing the light vest, in
darkness and in smoky entries. Several mines are
considering the use of light vests for personnel working
around moving machinery.

Another area examined was utilizing high-intensity
strobe lights (xenon-white flash tube) strategically located in
the entries to map out an escape route for evacuating miners
during an emergency. These weather resistant triangular
shaped strobe lights, with interchangeable reflective lenses,
are compact and lightweight, powered by a lithium AA
battery and provide visibility of 180 degrees. The strobe
lights can be activated by the wireless, through the earth
signaling system, such as the one installed at LLL. Ideally,
underground sensors would monitor the gases and smoke in
the passageways during a fire. By interfacing these data
with a computer, the best escape route could be determined
and the appropriate strobe lights remotely turned on.

During the in-mine rescue team simulations conducted at
LLL, strobe lights were positioned in the center of the entry
about 1.8-m from the floor and in the entry crosscuts
predetermined to be the best escape routes. Rescue team
members were told that a roof fall had occurred and severed
the main communication/lifeline. At that time, the strobe
lights were remotely activated. Team members detached
themselves from the main communication/lifeline and
successfully followed the strobe lights out of the smoke-
filled entries to the fresh air base. Team members felt that
by keeping their cap lamps off, the strobe lights were easier
to follow. Two hundred seventy one miners evaluated five
strobe light colors (red, green, blue, amber, and clear)
during these smoke training exercises. The most visible
color in the nontoxic white smoke was green and the least
visible color was amber.

A similar simulation was conducted for underground
mine personnel in a western mine. Miners, in groups of
five, entered smoke-filled (nontoxic white smoke)
passageways and followed strobe lights to the fresh air base.
Not only did this exercise allow miners to travel through
smoke in there mine (many for the very first time), but also
it gave them an opportunity to evaluate the strobe lights as
an escape aid. Miners felt that placement of strobe lights at
decision points was quite helpful and interfacing these
devices with an audio output would enhance the use of
strobe lights for mapping escapeways. The miners felt that
the colored reflectors currently mounted in the center of
their entries would not have helped them.

The concept of strobe lights to identify escapeways and
marking mine obstacles was successful in experiments at the
Lake Lynn Mine and several isolated passageways of a
western mine. In a larger mine, the uncertainties inherent
in a complex ventilation system would complicate this
process considerably. Additional research would be
required to evaluate the feasibility of using these devices in
larger mines and incorporating audio output with each strobe
light unit.

Another successful device that was evaluated in smoky
environments uses laser technology. Commercial laser
pointers are compact, lightweight, affordable, and have high
quality beams. They utilize laser diode technology and
several of these handheld battery powered pointers have
ranges of up to 732-m. Rescue team members’ evaluated
two class Illa laser pointers, red and green. The red laser
pointer, with a wavelength of 645 nm and output power of

3-5 mW, can operate continuously for 8 hrs. The green laser
pointer, with a wavelength of 532 nm and an output power of
1-3 mW, can operate continuously for 2-3 hours. The green
wavelength appears brightest to the eye, so a high power is not
required. Beam diameters are less than 1-mm.

These pointers are mounted to the miner's caplamps with
hose clamps. The momentary on/off switch is modified to
stay on. The team captain is fitted with the green laser and
the tailperson with the red laser. The laser beams were highly
effective in the smoke-filled entries, allowing team members
to easily determine the location of the captain and tailperson
and to stay in better alignment across the entry during
exploration. Figure 3 depicts the green laser beam cutting
through the smoke-filled entry.

During other smoke training exercises, the laser pointer
was effectively used to negotiate travel through a smoke-filled
passageway. Approximately 25 participants during each
exercise traveled 300-m in a nontoxic smoke-filled entry,
using a lifeline to lead them to fresh air. Visibility ranged
from 0.3 to 0.9-m and there were no tripping hazards in the
entry. Two to three participants entered the smoky entry at 40
to 60-sec intervals, until all participants were headed toward
the fresh air base. Another participant followed this group
with only the laser pointer to direct them to the other end (no
lifeline) and with their cap lamp turned off. The beam of the
laser pointer was continuously moved up and down and left to
right. When the beam hit the rib,roof, floor, or other
participants, a spot was seen. The participant with the laser
reached the fresh air base at the same time as the first
participant who entered the smoke.

Additional experiments were conducted with Class IIIa
yellow, orange, and green Helium-Neon lasers with
wavelengths of 594 nm, 612 nm, and 643.5 nm,
respectively. The output power and beam diameters were
similar to the laser pointers. The 110 VAC powered lasers
were mounted at graduated heights in an entry,
approximately 1-m from the rib, starting at 100-cm from the
floor. The three-colored laser beams were adjusted to
maintain the same distance and height ratio from the rib and
floor, 300-m away. The three laser beams showed up well in
dark areas. However, test results with thick smoke
indicated that these lasers were ineffective, with the beams
not visible 3-m from the laser sources. In comparison, the

Figure 3.-Green laser beam shining through smoke


of the event. The LLL has installed a device to accomplish
this, a wireless signaling system that transmits an
emergency warning, which can quickly reach every
underground miner. The low-frequency electromagnetic
field can penetrate kilometers of soil and rock to reach the
most remote shaft or tunnel, which makes it ideal for
underground signaling and paging. This system consists of
a low-frequency transmitter that can be strategically placed
to create an electromagnetic signal that can completely
envelop most mines without the use of repeater systems.
Figure 1 shows a typical configuration of the wireless
system for a mine. The transmitter loop antenna is on the
surface, and a receiver/transmitter loop antenna is
underground. The person-wearable receivers are small,
lightweight modules incorporated into the miner's caplamp
assembly. Upon receiving an emergency or paging signal,
the begins to flash, which in turn alerts the miner to
evacuate the mine or call the surface for a message,
depending on which signal is received. The system can also
turn devices such as strobe lights on or off. Additional
information on wireless signaling systems and medium
frequency radio communication systems for mine rescue can
be found in Conti’, Dobroski*.

A successful evacuation of miners during the Willow
Creek mine fire, that occurred in Helper, Utah, on
November 25, 1998, was attributed to a similar system, the
Personal Emergency Device (PED) Zamel’. This system
displays a message on a LCD display after the cap lamp
flashes. The paging system was activated when one miner
saw flames and telephoned the dispatcher to evacuate the
mine. The PED system allowed a mine-evacuation plan to
be safely carried out before the mine passageways filled
with smoke. All underground miners escaped in
approximately 30 minutes. There are currently 14 PED
systems installed in U.S. Coal Mines.

Identification and Seeing Through Smoke

NIOSH attempted to address several issues raised by rescue
team members that participated in the simulations at LLL.
One of the main concerns of the rescue teams was
identifying other team members, marking locations and
materials, such as crosscuts, brattice curtain, cribbing, and
other items that may be found in the smoke-filled entries, or
just maintaining a reference point. Chemical lightshapes
(lightstick, lightrope, and lightdisc), a technology that has

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Figure 1. Conceptual representation of a mine,
depicting capabilities of the signalling system.

been around for years, were found to be a valuable tool for
underground rescue teams. The lightshapes are non-
flammable and not a source of ignition, and they are
weatherproof, maintenance free, and nontoxic. Infrared
(IR) lightsticks are also available. To activate, just remove a
lightshape from the package, bend, snap, and shake.
Instantly, a source of light exists that can vary in intensity and
duration. The brightest lightstick lasts 5-min; the least
brightest, 12-hrs. Team members assessed the cylindrical
lightsticks during the simulations, both in white nontoxic
smoke and black toxic smoke produced from conveyor-belt
fires. Four lightstick colors were evaluated; clear, green, red,
and yellow. Team members, as shown in figure 2, attached
these lightsticks to the back of their helmets with plastic ties.
They can be also placed on the floor at various critical
locations and on obstacles during exploration. Of 403
members participating in the white nontoxic smoke training
simulations, 80 percent identified green as the most dominant
color seen, 9 percent identified red, 7 percent yellow, and
clear was the least visible color. Out of the 90 rescue team
members that participated in fighting the conveyor-belt fire,
85.4 percent felt that green was the most dominant color; red
was the least visible color. Lightropes were mounted around
the brim of the helmet, and chemical circular lightdiscs were
mounted on the back of the self-contained breathing-
apparatuses (SCBA's). Team members also evaluated other
lightshapes. The light-rope was found ineffective. In other
smoke training exercises, the participants turned off their
caplamp and held a green lightstick out in front of them, about
waist high. The lightstick was effectively used to negotiate
travel through a smoke-filled passageway. Lightsticks are
now a crucial component for many rescue team members as
well as underground miners.

Personnel working around moving equipment in low light
areas are always placed at risk due to their poor visibility to
the operator. The light vest is a new technology, developed
by LiveWire Enterprises, Inc., that uses a blue/green electro
luminescent fiber and a 0.5-mm copper wire coated with a
semiconductor material. It is safe, non-toxic, flexible,
impact and water resistant, portable and produces no heat.
An AC or DC power source is used depending upon its

Figure 2. Chemical lightsticks attached to the back
of miners helmets