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Provide reliable, early-warning fire detection instruments, telemetry, and control systems for noncoal underground mines. Approach Industrial-grade fire detection instruments and signal telemetry equipment were modified for long-term exposure to harsh underground mine conditions, then were installed in four mines to evaluate long-term performance and reliability. How It Works The elapsed time between the onset of a fire and its detection is critical because fires tend to grow in size and intensity with time. Early fire detection and warning permit the initiation of a mine's emergency plan (evacuation, fire fighting, etc.) while the fire is still small, or ideally, while it is still in the incipient stage. Fire detection and warning systems, utilizing sensitive heat, flame, smoke, and gas analyzers, provide the most rapid and reliable indication of a developing fire.

Jan 1, 1987

Compare the fire endurance of paneled steel stoppings with that of traditional concrete block Stoppings. Background Permanent stoppings or partitions arc used in mines to separate ventilation airways. The ability of stoppings to retain their structural integrity for a minimum length of time under lire conditions and prevent the spread of flame and toxic combustion products to an adjacent airway is critical. The success of miners in reaching safety during a fire depends largely on the presence of uncontaminated airways. Traditionally, permanent stoppings for coal mines are constructed of concrete blocks. Recently, paneled steel stoppings that satisfy many of the requirements demanded of permanent stoppings, such as incombustibility and strength, have been introduced. Their use also introduced concerns such as the ability of a steel stopping to maintain its ventilation control function when exposed to a fire and the potential that the fire could transmit enough heat through the stopping to ignite combustible materials on the unexposed side. To address these concerns, the Bureau of Mines investigated the fire endurance of galvanized steel and concrete block stoppings.

Jan 1, 1989

By D. M. Walters, C. M. van der Vyver, L. J. deVulliers

The occurrence of underground fires in narrow tabular ore- bodies where high density timber support is used is a dangerous and disruptive occurrence. The containment and extinguishing of the fire remains a very important consideration in reducing not only the loss in production time but also in limiting the extent of the area damaged by the fire. Mindful of this, Gold Fields have adopted and developed the inert gas generator system from its origins in Poland for use in Group precious metal mines. The system generates an oxygen- deficient atmosphere which is introduced in the fire area after this has been sealed. A number of problems had to be overcome to operate this system successfully within the infrastructure of these mines. Of particular significance is the operation of a jet engine, the prime component of the system, at air pressures encountered below sea level. The modifications have been found to be satisfactory to the point where, since 1992, ten underground fires have been extinguished using this system. Invariably, the areas affected by these fires were extensive (over 1 000 000 m3) and required continuous operation of these units over extended periods of time (in some cases in excess of 400 hours).

Jan 1, 1997

By Wood P. D, Pettifer G. R

In the upper coal surface in the Latrobe Valley, craters known locally as fireholes have developed due to prehistoric coal fires. They can be several hundred metres across and up to fifty metres deep, and are now filled with overburden materials varying from hard baked clays to very soft lacustrine clays. In addition to reducing coal reserves, continuous mining operations are seriously affected by fireholes. Large undulations in the upper coal surface result in a mixture of coal and overburden on the upper mining levels. The very soft lacustrine clays are unstable in the mine batters and the overburden dump, are difficult to handle on the bucket wheel excavator/conveyer system, and have insufficient bearing capacity for the large bucket wheel excavators. Early identification is essen- tial and both drilling and dynamic core penetrometer have been exten- sively used. However, this has not proved adequate in locating and defining the extent of all fireholes, due largely to their irregular shape. To overcome this a range of geophysical techniques has been trialled with very promising results. A trial area has been covered on a twenty metre grid using gravity and Geonics EM34 conductivity measurements and the same area has been covered at a closer spacing with high resolution magnetics. Image processing of contoured magnetic, EM34 conductivity and residual gravity data has resulted in very good correlation with drilling data.

Jan 1, 1989

By Louis Frost

"A FIRE which forced the sealing -of the east side of Dominion No. 16 Colliery in the Town of New Waterford, Nova Scotia, occurred on October 6th, 1952 (Figure 1).So far as can be ascertained, the fire was first noticed in the roof of No. 7 East Lateral, after a brushing shot had been fired in the pavement. There appears to .be no doubt that this shot •blew out, igniting a small feeder in the roof.Regular air measurements and air samples, taken over a long period prior to the fire, indicated that the ventilation was adequate, for at no time had the percentage of CH4 in the general air current exceeded one per cent in this location. The last regular monthly samples and air measurements, taken at the end of September, showed the condition of the ventilation to be:Return at the Top of No. 8 East WallQuantity .... 27,700 cu. ft. per min.CH4 .......................... 0.32 per centC02 ................................ 0.10 per centHowever, in the week preceding the fire the mine examiner on four occasions had reported small feeders of gas at the face of the brushing in No. 7 East Lateral.Figure 2 is a diagram of the working place where the shots were fired. The face brushing had been shot down at 3 :45 p.m. and cleaned up. Two 'hurdle screens' had also been erected, one close to the face brushing and the other fifteen feet from the face."

Jan 1, 1953

By W. Leblanc, J. Phalen

This paper tells the story of a serious mine fire on a mechanized longwall face in a submarine coal mine at Glace Bay, Nova Scotia. The story gives, in chronological order, a technical account of the steps taken to investigate, fight and contain the fire. The time during which the events took place spans from June 19 to November 7, 1975.

Jan 1, 1976

By D J. Brake

The risk from fire remains one of the most serious of underground mine disaster scenarios. The impacts of mine fires on the underground ventilation system and the production of toxic gases have been difficult to model and therefore assessments have relied largely on empirical data, historical precedent and subjective opinions. Underground fire modelling software has had limited availability and been technically challenging and time consuming to use especially for routine mine investigations. There has also been no well-accepted set of assumptions for fire modelling in mines, which has resulted in a lack of confidence in adopting its use more widely. This paper describes modelling of three critical fire scenarios in underground hard rock mines: a fire (LHD) in an underground diesel refuelling facility, a fire in an underground explosives magazine and a fire on an underground ore transport conveyor. Modelling was undertaken using VentsimÆs VentFIREÖ fire simulation module. It describes the basis of design, the key assumptions, the methodology used and provides examples of the outputs, conclusions and recommendations. It reviews the impacts of these fires on egress and entrapment strategies in the mine. Some general principles regarding improvements to ventilation circuit design based on this analysis are also recommended. Whilst the fire scenarios were based on actual case studies, they have been disguised for this paper.CITATION:Brake, D J, 2013. Fire modelling in underground mines using Ventsim Visual VentFIRE software, in Proceedings The Australian Mine Ventilation Conference , pp 265-276 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By Albert E. Ketler

The techniques for fire monitoring of conveyor belts in underground coal mines have been revolutionized by the advent of sensitive carbon monoxide sensors and computer monitoring systems. These new systems are rapidly replacing the previous thermal (fixed-point temperature) sensors that have been shown to be considerably less sensitive for early fire warning. CO is generally an excellent indicator of spontaneous combustion. However, the most recent non-flammable conveyor belt materials have been shown to "burn" with dense smoke, but without sufficiently high temperatures to produce much carbon monoxide. To cover this fire detection void, a smoke detector was developed to augment CO sensing for these new conveyor materials. However, computer monitoring provides the flexibility for handling this and other additional instrumentation as fire monitoring techniques evolve. CO, smoke and temperature sensing may eventually be advocated for complete fire monitoring.

Jan 1, 1987

By L. D. Savage

Several experiments were conducted using a large crib fire adjacent to a Kennedy Metal Products steel stopping in a simulated cross cut to evaluate the proposed mechanisms by which a mine fire would breach the stopping. Temperatures in the convective air paths on both sides of the stopping, at the surface of the roof and 16mm within the roof were measured to evaluate the effects of heat transfer. The results indicate that roof failure is the prime method of breaching this design of stopping.

Jan 1, 1996

By H. M. Wolflin

SOMEWHAT more than a year ago the writer collected some extensive notes on metal-mine fires and a paper on metal-mine fire prevention and fighting, a summary of these notes, was hastily pre-pared, with the assistance of G. Chester Brown, chief mining engineer, Industrial Accident Commission for the National Safety Council meeting. This summary, which is admittedly incomplete, is submitted in the hope that it will evoke some discussion that may result in a reduction in metal-mine fire hazard along the line. To accomplish such a reduction does not require the application of complicated scien-tific data. The use of just a little care, a small amount of thoughtfulness and a bit of common sense will work wonders. UNDERGROUND FIRE FIGHTING There may be some interest in a short list of con-clusions of a rather general nature that were reached in connection with some recent mine-fire fighting opera-tions. No effort has been made to cover the field; the items have been jotted down loosely, and very hastily, in the order in which they occurred to the writer. Originality is claimed for, only a few of them. 1. Temperature readings and analyses of mine-air samples, systematically taken, are invaluable aids to effective metal-mine fire fighting and recovery opera-tions. The analysis of the return-air samples fre-quently gives a surprisingly accurate indication of conditions existing underground. 2. Employees must be thoroughly trained in the use, of mine rescue apparatus, because a relatively slight difference in the amount of training makes a vast difference in the amount of work they can per-form under oxygen. In general, slender, wiry men make better apparatus men than those of heavy, more muscular physique, although there are frequent excep-tions to any such general statement. 3: Surprisingly high temperatures, up to 165° F. or 170° F. pan be endured for short periods by wearers of mine rescue apparatus if the air is dry, but lower temperatures, 135° to 140° F. are almost unbearable if the air is very moist.

Jan 2, 1922

By T. Glenn Pobanz

For more than fifty years Walter Kidde & Company, Inc. has engaged in the development and manufacturing of both fire suppression and detection equipment. Our initial work for the mining industry centered around dry chemical extinguish-ing equipment for mine haulage cars. To fulfill this need, Kidde engineered and developed a manually activated dry chemical system to provide protection for the wheel wells, cable reels, and motor compartments on various pieces of underground mining equipment. The next phase of mining operation fire protection for Kidde was the area of detection and automatic fire suppression for conveyor belt heads. Early in 1970, a field evaluation program and belt head demonstration unit was taken to 10 areas throughout West Virginia, Kentucky, Pennsylvania, and Ohio. This extensive field program was a joint effort with National Mine Service Company of Pittsburgh, Pennsylvania. The objectives of this program were to study mine hazard problems and to determine further requirements of mine operators. The resulting belt head detection system centered around our Continuous Strip Thermistor Core heat detector in conjunction with a Kidde stored pressure dry chemical extinguishing system. Continuous Strip detection has been in use for a number of years in aerospace applications. It has proven flexible and reliable for the rapid detection of overheat conditions and fires in engines of over half the aircraft flying today. The use of Continuous Strip gave us flexibility to protect surface areas over and around the actual conveyor belt head equipment. The nature of Continuous Strip allows us to bend, wrap, and attach the 20 foot long thermistor element over the desired protected points of the belt head. An integral part of the conveyor belt head protection system is the control panel utilizing our comprehensive knowledge of fire alarm control logic. This panel contains supervision circuits which sound trouble signals upon detecting a break in the Continuous Strip; breaks in the wiring to the remote electrical extinguishing activators or to the alarm bell; or loss of primary power. A separate control module provides the adjustable alarm temperature setting of the

Jan 1, 1971

Provide reasonably priced, reliable fire protection for blasthole drills. Approach An automatic fire sensing and suppression system using both dry and gaseous chemicals was developed, and is more shock and vibration resistant than similar industrial fire protection systems. How It Works Temperature sensors mounted in the drill's machinery house, hydraulic room, operator cab, and transformer area detect the heat from a fire, and trigger a sequence of actions. The same fire fighting sequence can be initiated from manual alarm boxes in the cab, hydraulic room, or machinery house. Electrical power to the drill Is immediately cut off, and a horn sounds to warn the drilling crew. After a 40-second, built-in, delay to allow time for drill's ventilating fan to stop, gaseous and dry chemical fire extinguishing agents are piped to and released in various rooms of the drill. The gaseous extinguishing agent (Halon 1301) is released in the machinery house, hydraulic room, and operator cab where dry chemical clean-up from electrical panels and machinery would be difficult and costly. Dry chemical is piped to the transformer room at the rear of the machine. Location of the principal components of the system are shown in the drawing.

Jan 1, 1979

Provide reasonably priced, reliable fire protection for front-end loaders. Approach Automatic fire sensing and suppression systems were developed and ruggedized for use on front-end loaders operating in harsh mine environments. How It Works Temperature sensors mounted in the loader's engine, transmission, and articulation areas detect the heat from a fire while it is still small and controllable. This triggers the release of the ABC class dry chemical extinguishing agent through a fixed piping system onto the fire. The system can also be manually activated from either the cab or ground level. Locations of the principal components of the system are shown in the drawing. Two control subsystems were designed to respond to varying fire protection needs and mine conditions. One subsystem only initiates discharge of the extinguishing agent. The other subsystem initiates visual and audible operator alarms if there is a fire sensed or if there is a fault in the control circuit.

Jan 1, 1979

Develop rugged, cost-effective fire protection for hydraulic shovels and backhoes. Approach Automatic fire sensing and suppression systems were designed and built for use on hydraulic shovels and backhoes. How It Works A line-type temperature sensor is mounted in the machine's engine and hydraulic pump areas to detect the heat from a fire while it is still small and easy to control. Two systems were tested. In one, the inside of the sensor consists of two conductors separated by a ceramic material whose electrical resistance decreases with increases in temperature. When heated to a predetermined temperature) the control circuit responds to the resistance drop. In the second system, the detection element of the sensor is comprised of a thin metal tube containing a hydrogen charged metal hydride wire. The tube is sealed at one end and is connected to a sensitive pressure switch at the other end. When exposed to the heat from a fire, hydrogen gas released from the metal hydride wire actuates the pressure switch.

Jan 1, 1980

By T. G. Carter

"During the early part of the 1980s, four new surface coal mines commenced operation in the Province of British Columbia. Each represented a major investment in both persons and materials in order to protect this investment in one significant area-the fixed portion of the surface coal handling system-a substantial amount of work was undertaken to ensure that the system was well protected from an outbreak of fire. A great deal of effort in this field had already been made by those coal mines which had been in operation for a number of years and experience gained at these operations was utilized in determining the level and extent of fire protection for the new mines.This paper summarizes the major problems, and suggests some of the methods of solution, in providing an adequate degree of fire protection for surface coal handling systems. It will also discuss the potential for gas and dust explosions together with ways to minimize this potential.The Fixed Coal Handling SystemNote: The word ""fixed"" has been used in its present context to denote that part of the coal handling system where the coal is moved via fixed installations such as a conveyor. It differentiates from that part of the system where coal is moved by mobile equipment.The raw coal delivered to the truck dump will undergo two major processes on its way to the rail load out. The first will be at the coal preparation plant where coal of specified quality will be extracted from the raw feed to the plant. If this coal is of metallurgical quality, and sometimes if it is of thermal quality, it will pass through a thermal dryer where part of the moisture acquired during coal preparation will be removed, i.e. the second process. As the complexity of both the coal preparation plant and the thermal dryer is such as to warrant separate considerations they will not form part of this paper. Each of the processes, however, is generally, housed in its own building, thus, containment of any hazards is usually more attainable than those existing or caused in the rest of the system."

Jan 1, 1988

By Lon D. Santis

The Code of Federal Regulations Title 30, Parts 56, 57, 75, and 77 require that detonators and explosives be separated by four inches of hardwood or equivalents when transported together in mines. This standard was developed to protect the explosives from initiation by the more sensitive detonators. The research reported here is an attempt to quantify the fire protection offered by four inches of red oak and other materials. Boxes with a volume of 6.75 cubic feet were made from four-inch thick rough green oak (RGO), two-inch thick RGO plied, two-inch thick #1 common (dried) red oak plied, and a metal/plywood composite. These and boxes meeting the Institute of Makers of Explosives' (IME) Safety Library Publication No. 22 were tested in bonfires. The boxes were instrumented with thermocouples, filled with detonators, and placed over a kerosene fire imparting about 16 kilowatts per square meter heat flux for up to 3 hours.

Jan 1, 1997

By Lon D. Santis

The Code of Federal Regulations Title 30, Parts 56, 57, 75, and 77 require that detonators and explosives be separated by four inches of hardwood or equivalents when transported together in mines. This standard was developed to protect the explosives from initiation by the more sensitive detonators. The research reported here is an attempt to quantify the fire protection offered by four inches of red oak and other materials. Boxes with a volume of 6.75 cubic feet were made from four-inch thick rough green oak (RGO), two-inch thick RGO plied, two-inch thick #1 common (dried) red oak plied, and a metal/plywood composite. These and boxes meeting the Institute of Makers of Explosives' (IME) Safety Library Publication No. 22 were tested in bonfires. The boxes were instrumented with thermocouples, filled with detonators, and placed over a kerosene fire imparting about 16 kilowatts per square meter heat flux for up to 3 hours. Tests showed that the wood boxes protected the detonators for over an hour with variations between the different trials. In the IME 22 container tests, detonators began exploding in as little as 17 minutes in one test and not for 2-/12 hours in another test. Detonators in the metal/plywood boxes began to explode in about 15 minutes but with minor alterations, were able to contain the detonators. The test results show that the exterior of an IME 22 container significantly affects its thermal properties. Defects in the form of cracks and the manner in which the container is closed have a significant effect on the performance of a detonator container in a fire.

By U .. C. Rojas, J .. C. Gomez

"Fire Refined Copper (EI Teniente Three Stars) has been produced at Caletones Smelter of Codelco Chile since almost the beginning of its operations.Due to changing features of the copper market, together with the targets on technical efficiency and productivity, it has become more and more relevant for copper industry to reach both, good final product quality and a proper environmental control.At present, copper refining process at Caletones Smelter takes place in two cylindrical tilting furnaces, where solid fluxes are injected through horizontal tuyeres into the molten bath. (Fig. N2 1)Solid reagents are pneumatically conveyed and injected into the liquid copper bath attaining excellent solid - liquid contact, so the impurities removal efficiencies are found to be high. Same injection tuyeres are used to introduce both oxidising agent (normal air) and reducing agent (reformed gas) into the molten bath. Air or nitrogen is used as conveying gas for solid reagents, depending on the process stage.This pap~r gives a fundamental description of the process and industrial results related to the injection of blend of sodium and calcium carbonates to remove arsenic and antimony, silica and granulated reverberatory slag to remove lead and a mixture of calcium carbonate and mineral coal to reduce the selenium content of the fire refined copper."

Jan 1, 1996

By Linda L. Chasko, Charles P. Lazzara, Ronald S. (deceased) Conti, William J. Wiehagen

Fire has long been a concern for underground mine workers. A mine fire can occur at any time and can result in a partial or total evacuation of mine personnel and the loss of lives. Fires can grow rapidly. Time is the critical element. Prompt detection, timely and accurate warnings to those potentially affected, and a proficient response by underground miners can have a tremendous impact on the social and economic consequence of a small underground fire. Fire preparedness and response have components of technology and people. These components can work synergistically to reduce the time it takes to bring the system back in balance. This report deals with the preparedness of miners to respond to underground mine fires. It is intended to aid the mining industry in understanding the various roles of emergency responders and the training techniques used to increase their skill levels. The report also presents a technology overview to assist in effective response to mine fires.

Jan 12, 2005

By Linda L. Chasko, Charles P. Lazzara, Ronald S. Conti, William J. Wiehagen

Fire has long been a concern for underground mine workers. A mine fire can occur at any time and can result in a partial or total evacuation of mine personnel and the loss of lives. Fires can grow rapidly. Time is the critical element. Prompt detection, timely and accurate warnings to those potentially affected, and a proficient response by underground miners can have a tremendous impact on the social and economic consequence of a small underground fire. Fire preparedness and response have components of technology and people. These components can work synergistically to reduce the time it takes to bring the system back in balance. This report deals with the preparedness of miners to respond to underground mine fires. It is intended to aid the mining industry in understanding the various roles of emergency responders and the training techniques used to increase their skill levels. The report also presents a technology overview to assist in effective response to mine fires.