Overviews

Remote Mine Fire Suppression Technology (PDF, 791 KB, 2007)
This paper presents a summary of remote mine firefighting technologies used in U.S. underground coal mines and the results of completed NIOSH research in that area.

The Status of Mine Fire Research in the United States (PDF, 176 KB, 2008)
This paper presents a summary of recent research accomplishments in a programn of research that is addressing mine fire prevention, detection, management and suppression. It also provides an overview of the next phase of the NIOSH mine fire research program.

Data & statistics

Analyses of Mobile Equipment Fires for All U.S. Surface and Underground Coal and Metal/Nonmetal Mining Categories, 1990-1999 (PDF, 1240 KB, 2004-01)
This report analyzes mobile equipment fires for all U.S. surface and underground coal and metal/nonmetal mining categories by state and 2 year time periods during 1990-1999.

Analysis of Mine Fires for All U.S. Metal/Nonmetal Mining Categories, 1990-2001 (PDF, 1793 KB, 2004-11)
This report analyzes mine fires for all U.S. underground and surface metal/nonmetal mining categories during 1990-2001 by state and six successive 2-year time periods.

Analysis of Mine Fires for All U.S. Underground and Surface Coal Mining Categories: 1990-1999 (PDF, 1611 KB, 2004-09)
This report analyzes mine fires for all U.S. underground and surface coal mining categories by state and 2-year time periods during 1990-1999.

Software

SPONCOM - Spontaneous Combustion Expert System
The SPONCOM expert system aids in the assessment of the spontaneous combustion risk of an underground mining operation. The knowledge base for the program is based on information gathered and correlated with NIOSH's experimental studies.

Hazards

NIOSH Highlights Mine Fire Research (PDF, 153 KB, 2008-05)
NIOSH is conducting a comprehensive program of research addressing metal/nonmetal and coal mine fire prevention, detection and suppression. They include the areas of spontaneous combustion, flame cutting and welding, conveyor belt fire suppression and remote methods for addressing coal mine fires.

Measurement & analysis

A 20-Liter Furnace Test Method to Determine the Combustion Gas Toxicity of Conveyor Belts (PDF, 220 KB, 1996)
Experiments were conducted with mine conveyor belt samples in a 20-L furnace and in a laboratory fire tunnel to measure and compare the major toxic gas concentrations evolved during the combustion of the materials. The toxic gas concentrations, measured simultaneously through a multiport sampling device and treated as yield values, included hydrogen chloride (HO), hydrogen cyanide (HeN), oxides of nitrogen (NO_x treated as NO₂), and carbon monoxide (CO).

CFD Modeling of Fire Spread Along Combustibles in a Mine Entry (PDF, 178 KB, 2006)
A computational fluid dynamics (CFD) program was applied to fire spread along combustibles in a ventilated mine entry. The rate of flame spread was evaluated for the ribs and roof of a coal mine entry, timber sets, and a conveyor belt. The CFD program predicted a flame spread rate of 0.0145 m/sec for an actual coal mine fire in which the estimated flame spread rate was 0.0086 m/sec. This overestimated flame spread rate was a possible consequence of the presence of inert materials in the mine entrys roof and ribs.

CO Dispersion from a Coal Fire in a Mine Entry (PDF, 338 KB, 2006-06)
Five mine fire experiments were conducted in a 2.08-m-high, 2.90-m-wide ventilated mine entry in NIOSH's Safety Research Coal Mine to determine the effect of the dispersion of carbon monoxide (CO) on mine fire detection. The criterion that the mine fire alarms occur within 15 min of the onset of flaming combustion could not be consistently met with the 10-ppm CO alarm. This suggests the use of lower CO alarm values or reduced CO sensor spacings for mine fire protection. It is demonstrated how computational fluid dynamics (CFD) can be used to model the CO dispersion downwind from the fire in support of a plan to optimize sensor spacings.

Computational Fluid Dynamics Modeling of Spontaneous Heating in Longwall Gob Areas (PDF, 599 KB, 2007)
Computational Fluid Dynamics simulations were conducted to investigate the spontaneous heating of coals in longwall gob areas with different apparent activation energies and reaction surface areas. The results are reported in this paper.

The Critical Ventilation Velocity in Tunnel Fires - A Computer Simulation (PDF, 528 KB, 2005-04)
Discusses a study that used a CFD program (fire dynamics simulator) based on large eddy simulations (LES) to model floor-level fires in a ventilated tunnel. The CFD results are compared with two simple theories of critical ventilation.

Determining the Root Causes of Flame Cutting and Welding Fires in Underground U.S. Coal Mines (PDF, 246 KB, 2006-06)
Mine Safety and Health Administration (MSHA) Reports of Investigation, MSHA Mine Accident Reports, and the MSHA Mining Industry Accident, Injuries, Employment, and Production Database were analyzed, and interviews and observations with mine workers and welders were conducted to determine the root causes of coal mine fires and explosions caused by flame cutting and welding operations. This paper discusses the root causes and potential means to reduce the number of fires and resulting fatalities and injuries caused by or due to flame cutting and welding.

Distributed Measurement of Conductor Temperatures in Mine Trailing Cables Using Fiber-Optic Technology (PDF, 63 KB, 1998-03)
Mine trailing cables operated above safe thermal limits can cause premature insulation failure, increasing electrocution and fire hazards. This paper describes a unique approach to measuring temperatures within reeled cable under dynamic test conditions.

Dynamic Temperature Measurement of Overheated Shuttle Car Trailing Cables in Underground Coal Mines (PDF, 220 KB, 1999)
A method is described to measure the conductor temperature of mine trailing cables during normal operation. The temperature is measured using an optical fiber located in the center of the metallic conductors.

Effects of Ventilation and Gob Characteristics on Spontaneous Heating in Longwall Gob Areas (PDF, 200 KB, 2008-06)
The results of field tests to understand how ventilation and gob characteristics affect the spontaneous heating process causing spontaneous combustion fires in longwall or worked-out gob areas are presented.

Evaluation of Deep-Seated Crib Block Fire Tests (PDF, 675 KB, 2008)
This paper discusses wood crib fire tests, conducted by NIOSH and MSHA, provides insight into the products of combustion and describes observations made during the application of the fire suppression agents.

Evaluation of Deep-Seated Crib Block Fires and Direct-Application Fire Suppression Agents (PDF, 838 KB, 2007-12)
NIOSH and MSHA are conducting research to test, evaluate, improve or modify coal mine fire-fighting strategies and methodologies through large-scale tests. Since wood is the second most abundant fuel available during a coal mine fire, it was decided that series of large-scale wood crib fire tests were needed to measure the products of combustion and to observe the capability of commonly available direct application fire suppression equipment, namely, fire extinguishers, water and gas-enhanced foam. This paper discusses the wood crib fire tests, provides insight into the products of combustion and describes observations made during the application of the fire suppression agents.

Evaluation of Mine Seals Using Ground Penetrating Radar (PDF, 1695 KB, 2005)
The National Institute for Occupational Safety and Health used ground penetrating radar technology to determine if each of three test mine seals were uniformly constructed. The results suggest that GPR could be used as a tool to evaluate mine seal characteristics and construction uniformity.

Evaluation of Remotely Installed Mine Seals for Mine Fire Control (PDF, 1592 KB, 2006)
NIOSH is conducting full-scale underground experiments at its Lake Lynn Experimental Mine to identify and remedy existing shortcomings of remote sealing technology in order to develop novel technologies and to transfer the new or improved technologies to the mining industry. This paper discusses the remote mine seal testing program and provides the results of the in-mine experiments.

Evaluation of Safety Shutoff Valve System on Methane Gas Pipelines Under Mine Fire Conditions (PDF, 994 KB, 1986)
The purpose of this investigation was to evaluate the integrity of the existing shutoff valves and actuators used under high-temperature conditions in the Bureau of Mines horizontal borehole methane drainage pipeline system and to determine the potential for improvement in the system. Based on the test results, it was concluded that the brass ball valve used in the Bureau methane drainage pipeline system can be retrofitted with an inexpensive fire bag to substantially increase its integrity under mine fire conditions.

Experimental and Modeling Investigation of the Effect of Ventilation on Smoke Rollback in a Mine Entry (PDF, 282 KB, 2005)
Results of diesel fuel fire experiments conducted to determine the critical air velocity for preventing smoke rollback. Experimental results compared very well with model predictions based upon a computational fluid dynamics (CFD) fire dynamics simulator.

Experimental and Modeling Investigation of the Effect of Ventilation on Smoke Rollback in a Mine Entry (PDF, 362 KB, 2006)
Results of diesel fuel fire experiments conducted to determine the critical air velocity for preventing smoke rollback. Experimental results compared very well with model predictions based upon a computational fluid dynamics (CFD) fire dynamics simulator.

Experimental Study of Flame Spread on Conveyor Belts in a Small-scale Tunnel (PDF, 377 KB, 2007)
This paper presents experimental results for conveyor belt flame spread from tests conducted in a small-scale tunnel. The purpose of this study is to investigate the effects of belt type, ventilation velocity, belt surface-to-roof distance and ignition source power on the flame spread properties.

Fire Detection for Conveyor Belt Entries (PDF, 1319 KB, 1991)
This report details the results of a series of large-scale experiments where small coal fires were used to ignite the conveyor belt at air velocities ranging from 0.76 to 6.1 M/s. Temperature, CO, and smoke levels were continuously measured to determine alarm time and level as the fire intensity progressed through the stages of smoldering coal, flaming coal, and flaming coal plus flaming belt. Analysis of the data leads to certain conditions of air velocity and sensor alarm levels that are required for early detection of conveyor belt entry fires.

Fire-Generated Smoke Rollback Through Crosscut from Return to Intake - Experimental and CFD Study (PDF, 1589 KB, 2006-06)
Two mine fire experiments were conducted in the NIOSH Pittsburgh Research Laboratorys Safety Research Coal Mine that demonstrated that smoke from diesel-fuel fires of 500- and 660-kW heat-release rates in a return airway can develop, without causing a complete airflow reversal, into a roof layer that can migrate upwind, forming a counterflow to the primary airflow in a crosscut. Subsequently, smoke can penetrate into an intake airway and create a hazardous atmosphere in the intake airway upwind from the fire.

Flammability of Noise Abatement Materials Used in Cabs of Mobile Mining Equipment (PDF, 207 KB, 2003)
Describes the flammability tests conducted on 15 to 20 different noise abatement materials of various chemical compositions and thickness.

Ignition of Hydraulic Fluid Sprays by Open Flames and Hot Surfaces (PDF, 188 KB, 2006)
A study of the ignition of non-fire-resistant hydraulic fluid sprays was conducted by NIOSH. Both an open flame and a hot steel surface were used as the external heat sources.

An Inexpensive Dual-Chamber Particle Monitor: Laboratory Characterization (PDF, 1986 KB, 2006)
Recent advances in technology have enabled the development of a small, portable, data-logging particle monitor modified from commercial smoke alarm technology that can meet the needs of surveys in the developing world at reasonable cost. There is significant potential for this monitor to facilitate the evaluation of interventions (improved fuels, stoves, and ventilation) on indoor air pollution levels.

Mine Fires - Measuring the Efficacy of Gas-Enhanced Foam (PDF, 336 KB, 2006)
NIOSH conducted research with US Foam Technologies, Inc., and On Site Gas Systems, Inc., on the remote application of extinguishing agents with the intent of improving deployment strategies to limit miner exposure and to help ensure the best possible outcome during a mine fire.

Ranking Factors Impacting Survival During Coal Mine Fires (PDF, 675 KB, 1993)
This study ranks the factors impacting survival during a coal mine fire. These authors found that a combination of actions was most effective. This combination was: installing lifelines; moderately decreasing air leakage; and decreasing the fire growth rate.

Simulation of Spontaneous Heating in Longwall Gob Area with a Bleederless Ventilation System (PDF, 450 KB, 2008-08)
To provide insights for the optimization of bleederless ventilation systems for U.S. underground coal mines, a computational fluid dynamics (CFD) study was conducted to model the spontaneous heating in longwall gob areas using a bleederless ventilation system.

Smoke Reversal Interaction with Diagonal Airway - its Elusive Character (PDF, 522 KB, 2006)
The reversal of smoke products-of-combustion from a mine fire was determined in a mine section with the airway connectivity of an electrical Wheatstone bridge. Four diesel-fuel fire experiments with fire heat-release rates between 504 and 771 kW were conducted in NIOSH's Safety Research Coal Mine. Computational fluid dynamics analysis of the smoke movement agreed with the measurements.

Summary of Combustion Products from Mine Materials: Their Relevance to Mine Fire Detection (PDF, 1052 KB, 1990)
The U.S. Bureau of Mines investigated the product-of-combustion (POC) characteristics of combustible materials used in typical coal mining operations in a series of experiments conducted in an intermediate-scale fire tunnel. The materials examined include wood cribs, transformer fluid, coal, conveyor belting, brattice cloth, and ventilation ducting. POC levels will vary not only between materials but also between stages of combustion and the conditions in which they are burning. This report summarizes the POC characteristics of each material and evaluates their effectiveness for early warning mine fire detection.

Case studies

Use of Rocsil® Foam to Remotely Construct Mine Seals (PDF, 1129 KB, 2008-02)
This paper presents an overview of remote mine sealing technology, introduces the use of Rocsil® foam for remote mine seal installations, offers a case study of the use of this rigid foam material to remotely construct a temporary in-mine seal and discusses technology improvements.

Engineering controls

Application of Gas-Enhanced Foam at the Excel No. 3 Mine Fire (PDF, 1881 KB, 2005)
This paper presents a discussion of the firefighting approach at the Excel No. 3 Mine and an analysis of the results of the application of gas-enhanced foam technology.

Coal Mine Inertisation By Remote Application (PDF, 941 KB, 2005-06)
The focus of this paper is the use of a GAG 3A jet engine system to either combat large out-of-control fires or render an entire mine inert when access to problem areas is difficult or impossible.

Comparative In-Mine Evaluation of Carbon Monoxide and Smoke Detectors (PDF, 1000 KB, 1996)
An evaluation of the comparative responses of five types of commercially available smoke detectors and a diffusion-mode CO detector under normal and reduced airflow conditions.

A Comparison of Mine Fire Sensors (PDF, 505 KB, 1995)
A report on research to determine the alarm times of smoke and carbon monoxide sensors and a point type heat sensor to slowly developing coal-conveyor belt fires.

Demonstration of Remote Mine Seal Construction (PDF, 1800 KB, 2004)
Covers development of novel technology for remote mine seal construction, evaluation of the materials used, construction practice, and follow-up testing.

Effectiveness of Various Concentrations of an Inert Gas Mixture for Preventing and Suppressing Mining Equipment Cab Fires: Development of a Dual-Cab Fire Inerting System (PDF, 558 KB, 2007)
NIOSH conducted a series of large-scale experiments to evaluate the effectiveness and safety of various concentrations of an inert gas mixture for preventing and suppressing cab fires. This has led to the choice of an optimum gas mixture concentration, discharged in the cab through a muffled nozzle system, for the development of a dual cab fire inerting system. Safety training programs need to accompany this technology. It is important to provide the operator not only with an engine fire suppression system but also with a cab fire protection system, effective both in preventing the ignition of flammable vapors in the cab and suppressing cab material fires.

The Effects of Ventilation and Preburn Time on Water Mist Extinguishing of Diesel Fuel Pool Fires (http://jfs.sagepub.com/cgi/reprint/22/5/379.pdf) (PDF, 207 KB, 2004-09)
Reports on the evaluation of water mist for the suppression of underground mine fires, such as fires in diesel fuel storage areas.

Evaluation of Gas-Enhanced Foam for Suppressing Coal Mine Fires (PDF, 968 KB, 2005)
Improvements in remote firefighting technology are needed to reduce miner exposure to the dangers of fires and possibly save the lives of those who may become trapped. NIOSH, in cooperation with U.S. Foam Technologies, Inc., conducted a series of experiments at the NIOSH Lake Lynn Experimental Mine to study the stability, transport, control, and fire extinguishing effectiveness of nitrogen-enhanced foam technology. This paper describes the mine test configurations and experimental results.

Evaluation of Smoke Detectors for Mining Use (PDF, 235 KB, 1995)
Six smoke detectors were measured with respect to visually obscuring smoke characterized by a corresponding optical density for smoldering and flaming coal combustion in a smoke chamber. The responsive characteristics of the detectors evaluated with respect to known smoke conditions in the smoke chamber shows their potential for use as mine fire sensors or part of a mine atmospheric monitoring system to improve mine safety.

Gel Sealants for the Mitigation of Spontaneous Heatings in Coal Mines (PDF, 2950 KB, 1995)
Reports on a USBM study of three gel sealant systems used to minimize air ingress to areas in the mine that can undergo self-heatings and specifically mines that sustain both floor heave and self-heatings.

In Mine Evaluation of Discriminating Mine Fire Sensors (PDF, 322 KB, 2002)
An evaluation of multiple mine fire sensor types for nuisance alarm discrimination. The response of multiple fire sensor types to three small coal fires and three small conveyor belt fires in the presence of diesel emissions was evaluated.

In-Mine Evaluation of Smart Mine Fire Sensor (PDF, 433 KB, 2008)
This paper describes the in-mine evaluation of a smart mine fire sensor system and discusses recommendations for improving the system.

Multiple Type Discriminating Mine Fire Sensors (PDF, 333 KB, 2003-12)
Researchers determined that a selection of different types of fire sensors could be used to discriminate mine fires from nuisance emissions produced by diesel equipment. A neural network (NN) was developed for application to coal, wood, and conveyor belt fires in the presence of diesel emissions and was evaluated with the successful prediction of 22 out of 23 mine fires based on a fire probability determination. The optimum sensor selection for the NN was composed of a carbon monoxide sensor, two types of metal oxide semiconductor sensors, and an optical-path smoke sensor.

Neural Network Application to Mine-Fire Diesel-Exhaust Discrimination (PDF, 291 KB, 2002-10)
Results of experiments to train a neural network to detect coal and styrene-butadiene-rubber conveyor belting fires. Six of the seven experiments were conducted in the presence of diesel exhaust.

Rapid Detection and Suppression of Mining Equipment Cab Fires (PDF, 557 KB, 2007-08)
This paper discusses a series of large-scale experiments conducted by NIOSH to evaluate the effectiveness of optical flame detectors, photoelectric smoke detectors, and combined ionization and photoelectric smoke detectors for rapidly detecting mining equipment cab fires.

Real-time Neural Network Application to Mine Fire - Nuisance Emissions Discrimination (PDF, 170 KB, 2004-05)
Discusses implementation of a real-time neural network which can discriminate mine fires from nuisance diesel emissions as part of an atmospheric mine monitoring system in NIOSH's Safety Research Coal Mine.

Reduction of Fire Hazards on Large Mining Equipment (PDF, 431 KB, 2008-09)
This paper describes NIOSH research on methods to reduce the fire hazards associated with large mining equipment, including the use of cab inerting systems to prevent the ignition of flammable vapors inside the cab and suppress fires originating in the cab.

Remotely Installed Mine Seals for Mine Fire Control (PDF, 1094 KB, 2006-03)
NIOSH is conducting full-scale tests at its Lake Lynn Experimental Mine to evaluate and improve remote mine seal construction technology. The main focus of this work is to develop reliable technology that will completely close the mine opening from floor to roof and from rib to rib. This paper presents the results of remote seal installations using grout-based materials.

The Use of Nitrogen-Enhanced Foam at the Pinnacle Mine Fire (PDF, 1866 KB, 2005)
This paper evaluates the effectiveness of remotely applied nitrogen-enhanced foam to aid in efforts to isolate and suppress a mine fire.

Training exercises

Focus on Prevention: Conducting a Fire Risk Assessment
This training package outlines a group activity. During this session trainees will: 1) learn about risk assessment concepts and tools and 2) conduct a risk assessment of their work environment. The guide outlines 6 steps to completion of a fire risk assessment and provides two forms that can be used to document the process. References for additional information are included. Conducting this activity with groups of workers on-site would result in the identification and prioritization of fire safety hazards. This would lead increased effectiveness in fire prevention and response planning.

I Can't Get Enough Air! - Proper Self-contained Self-rescuer Usage
You are the section foreman on the 17 Left longwall development section at the Paula Ann No. 3 mine. The section has been driven about 4,000 feet from 4 West Mains. One of the shuttle car operators took a call from the fireboss saying that there was smoke from an unknown source coming into your section. You attempt to contact someone to find out where the smoke is coming from but get no response. You and your crew start riding out of the section on the mantrip. When you encounter heavy smoke, you decide to take your crew and travel on foot in the belt entry which is on a neutral split of air. After traveling about 6 crosscuts in the belt entry, you encounter heavy smoke again, at which time you and your crew don your SCSRs. After donning the apparatus, you and your crew continue traveling outby in the belt entry. Near the mouth of the section, a miner in the group starts to have trouble breathing from his SCSR because he is "outbreathing" the device since his oxygen requirements are greater than the SCSR can supply. Soon more workers, including yourself, begin having trouble breathing. You must decide when to switch to another SCSR that you obtain from a cache along the escape route.

Low Coal Fire
You and your helper are working in an intake air entry at the face. The coal height is 28 inches. Heavy black smoke suddenly sweeps down on you from one of the intake air entries. You must decide what to do to warn others, to get to the assembly point, and to get out. The problem becomes more complicated when one of the miners is missing.

Vulcan Mine Ignition
You are the on-side shuttle car driver. Just after lunch, you pull across the last open crosscut, ready to go into #4 entry to load coal from the continuous miner. Just as you notice the line is down, an orange fireball covers up the continuous miner in the entry, the miner operator, his helper, and the foreman who was also in the entry. After the fireball dies down, through the white smoke in the entry you can see one miner down and the other two walking around by the continuous miner. You must decide what to do.

Belt Fire Exercise
You are the foreman for an 8 person crew that is advancing the headings of a longwall entry. You receive a call from the dispatcher reporting smoke coming out the belt entry from your section 5,000 feet outby your position. The air at the face is clear. You must decide how to evacuate the section, what equipment to take with you, gather information about the location and size of the fire, and determine if you should fight the fire or leave. The lives of the 8 miners you supervise, the lives of many other miners in the mine, and the well being of the mine depend upon your judgments and actions.

Escape from a Mine Fire
You are the foreman on a 3 entry longwall development panel 2,500 feet from the mains, and 15,000 feet from the portal. Suddenly a cloud of smoke comes up the belt entry. As you warn and assemble the crew the smoke becomes thick. A call from the surface orders the immediate evacuation of the section. The location of the fire is unknown. You lead the miners out the intake air entry only to encounter heavy smoke after a few crosscuts. You direct the miners to don their SCSRs and continue on. One miner cannot keep up and delays the escape of the others. Soon the smoke becomes so thick that visibility is only a few inches. The portal is still over two miles away. You must help your crew escape from the mine before their SCSRs are depleted, but you also do not want to leave the one miner behind.

Videos

Escape from Mine Fires
This videotape deals with the experiences of two miners in escaping an underground coal mine fire in 1988. It illustrates the importance of knowing effective self-rescue and escape procedures.

Recovery of Farmington #9: An Interview with Danny Kuhn
This video is designed to acquaint mine rescue personnel with certain aspects of rescue work that are not traditionally taught - the strain caused by continual work under adverse conditions; the problem of "survivor guilt" - being spared the fate of one's deceased buddies; and the possibility that post-traumatic stress can occur during the sometimes lengthy task of body recovery.

You Are My Sunshine
This video tells the story of the Sunshine Mine Disaster of 1972 through the eyes of 27 people who lived through it. The video explores what happened, what went wrong, and what were the lessons learned. The Sunshine Fire was the catalyst for the Metal/Nonmetal Health and Safety Act of 1977, which put in place the metal/nonmetal regulations that currently exist in this country.

Facilities

Fire Gallery
Evaluating the fire hazards of mine materials; fire fighting.

Fire Suppression Facility
A large-scale, state-of-the-art fire test facility.

Mine Fire Preparedness Facility
Evaluating technology and methods for fire suppression and conducting firefighting training.