Explosions In Coal Mines Research Articles

Preventing “the Needless Peril of the Coal Mine”: The Bureau of Mines and the Campaign against Coal Mine Explosions, 1910–1940

Preventing “the Needless Peril of the Coal Mine”: The Bureau of Mines and the Campaign against Coal Mine Explosions, 1910-1940 MARK ALDRICH There are a few of us alive yet. Oh God for one more breath. Ellen, remember me as long as you live. Good-bye darling. [Henry Beach, who died, trapped by an explosion in the Fraterville mine, Coal Creek, Tennessee, 1902.] 4:45 p.m.—They are going fast now. The bug light is still burning. Men are moving. All weak as kats. [Jay Smith, who died, trapped by an explosion in the Sonman E mine, Portage, Pennsylvania, 1940.]' The year 1907 had been a bad one for mine explosions: by Novem­ ber 200 men had been killed in ten major disasters. But as matters turned out, this was merely a tune-up. Pennsylvania inspector Henry Louttit worried about the Naomi mine, just south of Pittsburgh. It was gassy and worked with open-flame lamps and bare electric wires, even on the return air current. In November 1906 he read a letter from Francis Feehan, president of United Mine Workers (UMW) District 5, forwarding a miner’s complaint that the mine needed bet­ ter ventilation and that there was a “constant danger of serious explo­ sion.” Louttit visited the mine in February, May, and August 1907 and repeatedly wrote the management, warning that it was indeed Dr. Aldrich is professor of economics at Smith College. He thanks Michele Aldrich and the Technology and Culture referees for helpful comments on earlier drafts of the article, and Jim Cassidy of the National Archives for assistance with Bureau of Mines materials. A version of this article was presented at the 1993 meeting of the Pacific Division of the American Association for the Advancement of Science. 'Henry Beach is from Andrew Roy, A History of Coal Miners, 3d ed. (Columbus, Ohio, 1907), p. 7; Jay Smith is from “The Tragic Story of Approaching Death in Sonman Mine,” United Mine Workers Journal 51 (November 1, 1940): 10.© 1995 by the Society for the History of Technology. All rights reserved. 0040-165X/95/3603-0003$01.00 483 484 Mark Aldrich gassy and poorly ventilated. On November 18, Louttit again wrote the foreman, calling his attention especially to ventilation. The foreman replied the same day, informing him that “the law is being complied with.” On the evening of December 1, at about 7:45 p.m., Naomi exploded. The normal workforce was about 350 men. Fortunately, December 1 was a Sunday, and the evening force was small, only thirty-four men. Everyone was killed.2 Five days later the employees in Monongah, West Virginia, number 6 and number 8 mines were not so lucky. The mines had been con­ nected—a dangerous practice but one that saved the cost of an extra shaft—and the complete force of 367 men was at work. Five survived the blast. It was the worst mine explosion in American history. Inves­ tigators noted that working places had been driven long distances between breakthroughs so that probably little air got to the face. Despite dust and gas, open-flame lamps were used. Blasting was done with black powder while the men were in the mine, and no shot-firers were employed.3 Less than two weeks later two more tragedies struck in quick succes­ sion. The first was at the Yolande, Alabama, mine in which a miner’s open lamp touched off a gas and dust explosion. Of the eighty-seven men in the mine, fifty-seven were killed. Three days later, Pittsburgh Coal’s Darr mine in Jacob’s Creek, Pennsylvania, exploded. Darr was very dry and dusty, reported Pennsylvania’s inspectorJohn Bell when he visited in May 1906. Immediately after the inspection, Bell warned both the foreman and superintendent to use safety lamps, as he had found gas in “dangerous quantities.” Superintendent Archibald Black replied that he was sorry to hear of such conditions and assured Bell 2The Bureau of Mines defined a disaster as a single event in which five or more people were killed. Where there is some dispute on the number of lives lost, I have relied on bureau estimates from H. B...

Preventing "The Needless Peril of the Coal Mine": The Bureau of Mines and the Campaign against Coal Mine Explosions, 1910-1940

De 1906 a 1910, de nombreux mineurs moururent aux Etats-Unis a cause d'explosions dans les mines. Des etudes scientifiques effectuees par des geologues demontrerent que la poussiere de charbon etait tres explosive. Des mesures preventives, soutenues par le Bureau des Mines, s'imposerent alors afin de reduire la perte des ressources et des hommes

Rapid Sampling of Products During Coal Mine Explosions

This paper describes a U.S. Bureau of Mines investigation of large-scale coal dust explosions in an experimental mine using a high speed clectropneumatic mechanism for the rapid grab-sampling of gases and dusts. This technique enables themonitoring of pyrolysis and charring in fuel dust particles, and the collection of gaseous combustion products, in both large and small-scale explosions. Data obtained from full-scale dust explosion tests at the Bureau of Mines Lake Lynn Test facility show the following: Rapid sampling appears to “freeze” the burned gas compositions at the flame temperature values.Gas samples taken entirely in the flame zone consist of pyrolysis and combustion products with very low residual oxygen.The particles collected in the flame zone show signs of extensive pyrolysis and charring. Measurements of gas concentrations and particle flame temperatures suggest that char burning may have occurred in the flame zone.

Confidence Regions and Tests for a Change-Point in a Sequence of Exponential Family Random Variables

Maximum likelihood methods are used to test for a change in a sequence of independent exponential family random variables, with particular emphasis on the exponential distribution. The exact null and alternative distributions of the test statistics are found, and the power is compared with a test based on a linear trend statistic. Exact and approximate confidence regions for the change-point are based on the values accepted by a level a likelihood ratio test and a modification of the method proposed by Cox & Spjøtvoll (1982). The methods are applied to a classical data set on the time intervals between coal mine explosions, and the change in variation of stock market returns. In both cases the confidence regions for the change-point cover historical events that may have caused the changes.

Confidence regions and tests for a change-point in a sequence of exponential family random variables

SUMMARY Maximum likelihood methods are used to test for a change in a sequence of independent exponential family random variables, with particular emphasis on the exponential distribution. The exact null and alternative distributions of the test statistics are found, and the power is compared with a test based on a linear trend statistic. Exact and approximate confidence regions for the change-point are based on the values accepted by a level x likelihood ratio test and a modification of the method proposed by Cox & Spj0tvoll (1982). The methods are applied to a classical data set on the time intervals between coal mine explosions, and the change in variation of stock market returns. In both cases the confidence regions for the change-point cover historical events that may have caused the changes.

Coal as a Conventional Source of Methane: Review and Analysis of a 31-Well Production Area in the Mary Lee Coal Seam, Tuscaloosa County, Alabama

Summary This paper presents a review of the actual production, sales, and economicdata from a 31 well production area developed by a joint coal industry/gasindustry effort owned equally by Jim Walter Resources, Inc. (JWR), a subsidiaryof Jim Walter Corporation of Tampa, Florida and Enhanced Energy Resources, Inc.(EER), a subsidiary of Kaneo Services, Inc. of Houston, Texas. The uniquereservoir characteristics of the coal environment are described in brief, acomparison of actual methane production from coal with computer modelpredictions is production from coal with computer model predictions ispresented, and the capital and operating costs are presented, and the capitaland operating costs are discussed with specific emphasis on the economicresults. This information differs from similar previous work in that economicvitality is now apparent whereas previous inquiries, were essentiallyrestricted to the technical reservoir engineering characteristics and thephysical capability of coal to desorb (produce) methane. There are a number ofpublished papers on this important technical aspect, several of which arereferences for this presentation. Production Area 1 (31 well production area) has been generating an operatingprofit for the past 15 months. Profits have increased substantially in the pastseven Profits have increased substantially in the past seven months as a resultof the completion of an 3" transmission line and reduced operating costs. Initial production commenced in late 1979. A five well pilot project wasevaluated for approximately two years before commercial development commencedin late 1981. A total of 31 wells were drilled by mid-1982. First salescommenced in February of 1982. The economic viability is demonstrated based on actual operating profits over the past fifteen months and current experience with respect to improvements in operational techniques and costs. These data are applied to the computer forecasts of long term deliver abilities for projections of expectedeconomic performance. projections of expected economic performance Introduction Although coal has been used as an energy source since prehistoric times, thevast coal reserves in the United prehistoric times, the vast coal reserves inthe United States (approximately 26 percent of the worlds known coal reserves)have taken on added significance as a clean energy source with the successful extraction of methane from coal seams through vertical well bores. During the process of coalfication considerable quantities of gases areevolved from the indigenous carbonaceous material. These gases include methaneand heavier hydrocarbons, carbon dioxide, nitrogen, oxygen, hydrogen, andhelium. The primary constituents are methane and carbon dioxide. These gaseshave been observed in coal mines and the emmission of methane from coal bedshas created problems in mining since the inception of the industry. In manycases the presence of methane can cause the cessation of mining operations. Regardless of the range of severity, methane presence in coal mines isdetrimental to safety, increases mining costs, and reduces efficiency of mineproduction. Quantities of methane and air in proper proportions (5 to 15%present methane) result in explosive mixtures. It is the ignition of thesemixtures that cause the disastrous explosions in coal mines. Concurrently, however, methane being the principal constituent of natural gas offers apotentially large supply of energy for traditional residental, commercial andindustrial markets. Historically, mines are engineered to vent as much methane as possible. According to the U.S. Department of Energy (DOE) estimates, in excess of 250million cubic feet (MMcf) of methane gas is vented daily as a routine safety measure for underground mining operations. However, this vented methane fromactive mines is only a small percentage of the potentially producible methaneavailable from properly developed vertical well programs. An alternate toventing is to reduce the coal extraction rate. Both solutions are expensive and wasteful. The nation's resource of gas trapped in coal is extremely large (See Figures17 and 18). According to the DOE the amount exceeds 700 trillion cubic feet(Tcf). Of this 700 Tcf it is estimated that approximately 300 Tcf isrecoverable; this is the equivalent of a ten-to-twenty-year supply based on1981 U.S. consumption rates.

Points: Cardowan coal mine explosion

Points: Cardowan coal mine explosion

Cardowan coal mine explosion

Cardowan coal mine explosion

Cardowan coal mine explosion: experience of a mass burns incident.

A coal mine explosion 1700 feet (516 m) underground and two miles (3.2 km) from the pit head resulted in 40 casualties. Two hours elapsed between the explosion and the arrival of patients at hospital. Six patients suffered mechanical injuries, only one of which was life threatening. Thirty six suffered burns; in 18 over 15% of the total body surface area was affected. Nineteen patients had a mild respiratory upset requiring oxygen treatment. The average length of inpatient stay in those admitted was 24 days. Early assessment and treatment in the accident and emergency department was relatively simple because of the large proportion of burn injuries. Lack of communication between site and hospital made administration of the disaster difficult.

Coal dust flames: A review and development of a model for flame propagation

Coal mine explosions have been a problem for hundreds of years. The projected need for coal as an energy source will demand increased subsurface mining, in turn requiring improved techniques for the prevention of dust explosions. Preventive procedures, however, must rely on fundamental knowledge concerning the behavior of coal dust combustion. To this end, a review of coal dust combustion as reported in the literature is presented, and a mathematical model of flame propagation through coal dust-air mixtures is developed in detail. The model is basically used to predict burning velocities and to study the structure of coal dust-air flames. It is well known that coal particles burn in a very complicated manner. The combustion process includes heterogeneous surface reactions, devolatilization and subsequent reaction of the volatile components, swelling, cracking, and other physiochemical changes to the particles. In addition, it is known that coal particles do not always burn simply as shrinking spheres, but can burn internally and form cenospheres (hollow spheres) as well. The composition of the volatiles released, and the combustion itself, depend upon the rate of heating in a flame, thereby making analytical description of the process extremely difficult. This paper reviews the important studies reported in the literature which describe both the heterogeneous combustion processes for coal particles, including rapid pyrolysis toward volatile matter, and the subsequent gas-phase (homogeneous) reactions of the volatiles with the air. For example, the rate of heating of the coal particles determines the ratio of volatiles to fixed char in dry (ash-free) coal. Therefore the chemical source terms in any model must attempt to include as much as is known of the reported information on this key aspect. In addition, discussion is included of the experimental measurements carried out with coal dust flames in an attempt to categorize the data into two major classes; Class I experiments, having been conducted in open tubes or on small burners, and Class II experiments performed in enclosed furnaces or ducts. The major role of such enclosures is to act as a shield against heat losses, which can have a pronounced effect on the measured flame speed. It is our contention that the Class II tests are described by our model. The model that has been developed predicts steady (laminar) flame structure and flame speeds for premixed coal dust-air mixtures. The model takes into account radiative transport, two-phase flow conservation equations, heterogeneous carbon gasification and rapid devolatilization of the coal particles, and subsequent gas-phase combustion of the volatiles.

A physical description of coal mine explosions. Part II

This report is the latest in a series describing recent research on full-scale explosions of dust and gas in the Experimental Mine of the U.S. Bureau of Mines. This research is aimed at reducing the fire and explosion hazards of underground coal mining in the U.S.A. The fluid dynamics of coal dust explosions propagating through a new double entry facility (with 3 cross cuts) are described and compared with earlier findings in a single entry mine. The relation between flame speed, pressure, and dust cloud dispersion is analyzed. The internal chemical and physical structure of the complex combustion zone are examined by means of fast gas sampling of combustion products, and by measurement of dust cloud temperatures by rapid response pyrometers. These results are compared with those predicted by equilibrium theory. These zones are characterized by slow mixing and reaction progressing to equilibrium values. Further insight into the chemical and physical nature of these explosions is gained by determination of the limits of explosibility of mixtures of coal dust of different ranks with air, rock dust, and salts. Measured values are compared with values predicted by a limit thermal model which assumes propagation only by combustion of volatiles. Certain salts are shown to be somewhat more effective inhibitors than others, with a different order from that measured in small scale apparatus.

Underground explosions in coal mines.

Underground explosions in coal mines.

A physical description of coal mine explosions

Among the many hazards of underground coal mining, explosions of natural gas and coal dust continue to pose a threat, in spite of advances in safety practices. The U.S. Bureau of Mines has conducted research in the causes and prevention of coal mine explosions in its Experimental Mine. As a result of extensive instrumentation of this full-scale facility and systematic analysis of results, a physical description of coal mine explosions is presented, with emphasis upon unsteady fluid dynamics. In a single long entry, useful correlations are shown between flame speed, particle velocity, and static pressure rise. How this knowledge may be applied to the design and application of explosion barriers is presented and the role of coal volatiles in dust explosions is briefly discussed.

Waterproofing of stonedust.-The effect of waterproofing of stonedust used for arresting and suppressing explosions in coal mines is investigated : 8F,2T,5R. Int.J.Rock Mech.Min.Sci.V11,N8,Aug.1974,P319–323

Waterproofing of stonedust.-The effect of waterproofing of stonedust used for arresting and suppressing explosions in coal mines is investigated : 8F,2T,5R. Int.J.Rock Mech.Min.Sci.V11,N8,Aug.1974,P319–323

Waterproofing of stonedust

Stonedust is used in arresting and suppressing explosions in coal mines. Its dispersibility is adversely affected when exposed to underground mine environment. By waterproofing, this deleterious effect can be counteracted. Limestone dust has been waterproofed by Stearic, Palmitic and Oleic acid with different quantities (0·05, 0·1 and 0·2 per cent by weight). The effect of waterproofing on moisture adsorption, dispersibility, loss in inerting property and bulk density of the stonedust has been investigated.

Coal Mine Explosions: Seasonal Trends

An analysis of disaster reports on coal mine explosions indicates that gas explosions are randomly distributed throughout the year, whereas dust explosions (which may or may not be triggered by a gas explosion) occur with greater frequency during the dry fall and winter months. The lack of adequate moisture during cold weather tends to increase the rate and severity of the dust explosions.

Atmospheric Conditions and Explosions in Coal Mines

URING the long history of coal mining a belief has developed among miners that mine explosions are often associated with stormy weather. This widespread theory is so strongly held that men have sometimes refused to work in mines on stormy days. Coal companies also acknowledge the possibility of such a relationship; and because they do, extra precautions are taken in some mines during stormy weather. This paper presents some results obtained from an investigation into the effect of daily and seasonal changes in atmospheric conditions on the explosive compounds present in coal mines. Attention is focused on the possibility that such changes produce conditions in mines conducive to disastrous explosions. It is not surprising that there is a high accident rate in coal mines. Operating heavy machinery underground in cramped space and cutting and moving thousands of tons of coal each mining day are bound to make mining hazardous. Although explosions occur less often than other accidents, they usually result in a high death toll, and miners have grown to fear them more than any other type of accident. Several compounds present in coal mines are ignitible. Two, methane gas (CH4) and coal dust, may occur in such abundance that their ignition results in disastrous explosions. That explosions in coal mines result from combustion of gas has been recognized from the early days of coal mining; that coal dust alone can be an explosive element is a more recent realization. Coal dust as an explosion hazard, though early recognized by many mining experts, was not accepted by the majority of coal-mining interests in the United States until convincing tests had been carried out at the Pittsburgh testing station in 1908 and 1909.

Atmospheric surface pressure related to coal mine explosions

Investigations into the synoptic situations preceding explosions in coal mines during the past 12 years show the feasibility of forecasting periods of dangerous accumulation of combustible gas mixtures in coal mines. Several physical, as well as some psychological, aspects are discussed.

Explosion waves and shock waves. IV—Quasi-detonation in mixtures of methane and air

The possibility of detonation in mixtures of methane and air, apart from its theoretical interest, is of practical importance in connexion with the study of explosions in coal mines. Many attempts have been made experimentally to increase the violence of explosion or the intensity of combustion of mixtures of methane and air to see if speeds of flame and effects of violence comparable with those of detonation could be obtained. Mason and Wheeler noted that restrictions in the path of an explosion accelerated the flame, and observed that as the flame of a methane-air mixture passed through the second of two restrictions placed in a 30·5-cm. tube “the development of the detonation wave appeared imminent”. The experiments were continued by Chapman and Wheeler, who obtained a maximum speed of 420 metres per second beyond the restricted section of a tube 5 cm. in diameter. The effect of the restrictions was in their opinion to induce rapid motion in the mixture through which the flame was travelling.

Firedamp Explosions and their Prevention

The steady decline in loss of life arising from firedamp explosions in coal mines of itself bears testimony to the precautionary measures which have been developed to minimise this ever-present danger. The authors have embodied in short compass an account, drawn largely from papers published during recent years by the Safety in Mines Research Board, of the properties of firedamp, its possible means of ignition in a mine, and how, by the construction, maintenance, and testing of apparatus used in coal mines, the hazard of explosion may be minimised.