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By Charles L. Parsons

During the past year, in producing 500,000,000 tons of coal we wasted or left underground, in such condition that it probably will not be recovered in the future, 250,000,000 tons of coal; we turned loose into the atmosphere a quantity of natural gas larger than the total output of artificial gas during the same period in all the towns and cities of the United States; we also wasted or lost in the mining, preparation, and treatment of other important metalliferous and non- metalliferous minerals from 10 to 50 per cent of the year's produc- tion of such minerals. These losses serve to indicate the importance of inquiries and investigations by the Federal Government for the purpose of lessening the waste of essential resources-investigations on the same general lines as those looking to a reduction in the loss of life in the mining operations of the country and the far more exten- sive investigations looking to the more efficient production and use of agricultural products, both of which are being conducted by the Federal Government. In a consideration of the possible activities of the individual, the State, and the Federal Government in behalf of a less wasteful use of our mineral resources certain facts and principles should be kept clearly in mind, namely: That the present generation has the power, and it will exercise the right, to use as much of the country's resources as it actually needs; there can and there will be no such thing as stinting the present gen- eration by bottling up resources for the use of the future. That the Nation's needs are not likely to be curtailed; these needs will increase with the extent and diversity of the Nation's industries, and they will increase more rapidly than population increases, for the reason that the per capita consumption of mineral products is rapidly increasing; and That the men of this generation will not mine, extract, or use these resources at continuous financial loss to themselves in order that some- thing may be left for the use of future generations; there can be no such thing as a mineral industry without profits.

Jan 1, 1912

The Mine Safety and Health Administration (MSHA) defines an independent contractor as "any person, partnership, corporation, subsidiary of a corporation, firm, association or other organization that contracts to perform services or construction at a mine." Contractors that perform specific types of work are required to report the number of employees who perform work at coal mines and at noncoal mines.

Feb 1, 2005

By E. A. Barrett, L. L. Rethi, B. Fotta

Employment and accident trends of independent contractors working at coal and noncoal mines in the United States are reported. Data include employee hours and accidents, both fatal and nonfatal, from 1985 through 1994. Also noted are increases or decreases in certain accident classifications and accident rates, particularly those which have shown significant change during the ten-year period.

By A. E. Prokop, J. P. Rider

Previous research on continuous mining operations has shown that significant interactions exist between dust control parameter application and the resulting respirable dust levels, but simply increasing the level of the controls does not guarantee a reduction in respirable dust levels. Full-scale laboratory tests are being conducted to provide information to longwall operators which would assist them in selecting control parameters that would reduce dust levels for mine-specific conditions. The interactions between face air velocity, shearer water quantity, drum water spray pressure, external water spray pressure, and spray system design were evaluated in a simulated 2.13. m (7-ft) coal seam for two cutting directions. Locations around and downwind of the shearer were monitored to evaluate relative changes in respirable dust levels as a function of each control parameter.

By Thomas J. Fisher, Thomas Novak

Strong circumstantial evidence suggests that lightning has initiated methane explosions in abandoned and sealed areas of underground coal mines. The Mine Safety and Health Administration (MSHA) investigated several of these occurrences within recent years. The investigated explosions occurred at significant depths, ranging from 500 ft to 1200 ft. Data from the National Lightning Detection Network indicate a definite correlation between the times and locations of the explosions with those of specific lightning strikes. This paper addresses the question, "Can lightning cause potential differences capable of igniting methane-and-air mixtures at overburden depths at which underground coal mining occurs?" A mine depth of 600 ft was selected for this initial study. Computer simulations were performed, with and without the presence of a metal- cased borehole extending from the surface to the mine level. CDEGSTU software from Safe Engineering Services & Technologies, Ltd (SES) was used for the simulation.

By Gerrit V. R. Goodman, Charles D. Taylor, Edward D. Thimons, Jay F. Colinet

The importance of controlling respirable dust and methane gas levels in underground coal mining cannot be underestimated. While respirable dust can significantly affect the occupational health of underground coal miners, methane gas accumulations pose significant safety concerns for these same workers. Water sprays and machine mounted dust scrubbers offer effective control of respirable dust exposures and methane gas accumulations. Water must not only be applied carefully to avoid dust rollback to the machine operator but must create sufficient turbulence to remove dead zones that could contain high concentrations of methane gas. While the flooded-bed dust scrubber has been generally responsible for decreased worker exposures to respirable dusts, this device has proved effective in controlling methane levels at the face. This paper reviews practical applications of water sprays and dust scrubbers to control respirable dust and methane gas on continuous miner faces.

Jan 4, 2000

By M. J. Brnich

The purpose of this US. Bureau of Mines study was to assess the ability of trainees to don an unfamiliar self-contained self-rescuer (SCSR) after having become familiar with how to put on a different type of apparatus. Prepractice instruction was the same for all individuals learning to put on a device: a step-by-step, hands-on talk-through using the "3+3" method. Subjects were assigned to groups that had their initial donning instruction derivered on either the Draeger QXY-SR60B or the CSE SR-100. Trainees' performances were then evaluated using the other model. Donning trials were analyzed using a number of measures. It was found that SCSR design had a moderate influence upon how well the doming task transferred.

Jan 1, 1992

By George S. Rice, O. P. Hood

The need of protecting mines from the danger of inflow of natural gas from neighboring wells has become more apparent each year since it was found that oil and gas underlie the productive coal measures of Pennsylvania, West Virginia, Ohio, Indiana, Illinois, Kansas, Oklahoma, Colorado, and Wyoming, and, to some extent, the coal measures of other States. The proximity of the known gas and oil areas in the United States to the coal fields and the manner in which the fields overlap in certain States are shown in the map comprising the frontispiece (Pl. I). As the result of many requests received from various sources a conference to consider the protective measures necessary to insure the safety of mining operations in gas and oil fields was called by the Director of the Bureau of Mines to assemble in Pittsburgh, Pa., Feb- ruary 7 and 8, 1913. To this conference were invited a considerable number of gas-well, oil-well, and coal-mine operators within conven- ient distance from Pittsburgh, as well as State geologists and State mine inspectors from a distance. Gas and oil wells are also found near other kinds of mines, such as shale and limestone mines in western Pennsylvania, but these cases are so few that for this and other reasons it was deemed best to con- fine the present inquiry to the consideration of the questions involved in connection with coal mines. It was also not thought advisable to consider the protection of mines from other kinds of bore holes than those for gas and oil, such as coal-prospecting holes, drilled either with churn or diamond drills, or salt wells and artesian wells, because little trouble has been ex- perienced in mining operations from these classes of wells. There- fore the following papers and discussions concern almost entirely the following relations between coal mines and gas and oil wells: (1) Protection of coal mines froin gas and oil wells penetrating -through: (a) Open workings; (b) inaccessible spaces or goaves; (c) pillars, or coal which may be left as pillars. (2) The manner of drilling gas and oil wells passing through workable coal beds so as to provide protection for future mining. The preliminary inquiries of the engineers of the bureau had dis- closed that there was no uniformity in the methods of protecting mines against the leakage of gas from wells, that thousands of wells in coal fields are abandoned yearly without adequate plugging, and without surveys or records being kept to show the location of the holes, from which the casings are generally pulled. According to the State geologist of Pennsylvania, as many as 3,000 wells are being drilled annually in Pennsylvania, 2,000 of these holes being aban- doned within a single year. It is such unplugged, uncharted wells that are the greatest menace in mining. The quantity of gas that the wells produce, although not sufficient to be commercially avail-

Jan 1, 1913

By D. Harrington, M. W. Von Bernewitz

"The erection of barricades by men who are shut off from escape in mines at time of fire or after an explosion has been consistently advocated by the United States Bureau of Mines. Largely through the publicity given by the bureau to this excellent type of emergency safety endeavor, several hundred lives have been saved during the past 20 years. One of the earliest instances of barricading in the United States of which there is fairly complete record was in connection with the Cherry mine fire in Illinois in 1909; in this fire 259 lives were lost, but 20 men were saved by two barricades and were brought safely to the surface after seven days. In another coal-mine fire, followed later. on by an explosion, at Delagua, Colo., in 1910, 79 lives were lost, but 18 men saved themselves by erecting canvas brattices or barricades; the miners in one barricade were removed safely after five hours and those in another after 21 hours. In 1911, after an explosion in a coal mine at Briceville, Tenn., in which 84 lives were lost, five persons were brought out alive after 58 hours behind a barricade. Twenty hours after an explosion in which 73 were killed at McCurtain, Okla., in 1912, 13 men were taken out alive and one dead from behind a barricade or partition constructed of canvas. In 1914, after an explosion at Eccles, W. Va., in which 181 were killed, 35 men barricaded themselves in one place and after four hours were brought to the surface alive; this barricade was also of canvas. In 1915, 112 men were killed in an explosion at Layland, W. Va., but two groups of men, 47 in all, were able to barricade themselves; after four days 46 men were rescued alive, but one man was dead. In 1915, an explosion at Boomer, W. Va., killed 23, but 27 others barricaded themselves in one place and after seven hours came out alive. All of the foregoing instances of barricading were in coal mines. In 1917 there were three cases of barricading in a Montana metal-mine fire (the North Butte) during which 163 lives were lost. One of the barricades, sheltering 19 men, failed because the region barricaded was in porous broken ground through which the poisonous gases seeped and killed the entire group. From another of the barricades, engineered by an assistant foreman, 8 men were taken out, 6 uncon¬scious and 2 dead, 50 hours after the fire started. The 6 unconscious men lived, out the assistant foreman who directed the men was one of the 2 who had died. In the third case of barricading in this metal-mine fire,,men, also led by an assistant foreman, kept themselves closed in for about b6 hours and then broke barricade or bulkhead, 25 oing in one direction to safety, and 4, including the assistant foreman, going in another direction to death from poisonous gases. There have been a number of other cases of barricading, some successful and others a failure. Probably the worst failure was that in the argonaut (gold) mine fire in California in 1922; all of a group of 46 miners behind a barricade were found dead when reached after 21 days."

Apr 1, 1933

By Sinisa M. Djordjevic, Isaac A. Zlochower, Kevin J. Liekhus, Cindy A. Loehr, Kenneth L. Cashdollar

An experimental program was conducted to evaluate the accuracy of some current methods for predicting the flammability of gas mixtures containing hydrogen and flammable or nonflammable volatile organic compounds (VOCs) in air The specific VOCs tested were toluene, 1,2-dichloroethane, 2-butanone, and carbon tetrachloride. The lower flammability limits (LFLs) of gas mixtures containing equal molar quantities of the components were determined in a 19.4-1 laboratory flammability chamber using a strong spark ignition source and a pressure criterion for flammability. All but one of the LFL values for the individual components were in agreement with earlier literature values. However, the LFL of l,2-dichlorocthane was found to be significantly lower than the range of values reported for previous determinations in smaller chambers. Two methods for calculating the LFL of mixtures were considered. The Group Factor (atomic) Contribution Method was determined to he generally more accurate than the LeChatelier Method for estimating the LFL of the gas mixtures reported here, although the LeChatelier Method was usually more conservative. The Group Factor Method predicted higher values (nonconservative) for the LFLs of several mixtures than were experimentally measured. For the case of a mixture of hydrogen and carbon tetrachloride, the Group Method estimation of the LFL was seriously in error.

Objective: To identify and evaluate a durable, flexible, and practical stopping to direct ventilation airflows in large-opening metal/nonmetal mines.

May 1, 2006

By J. S. Peterson, G. P. Cole

The National Institute for Occupational Safety and Health (NIOSH), Pittsburgh Research Center (PRC), has conducted research to improve electrical fault detection on coal mine direct current (dc) trolley systems. Present circuit breaker protection systems are current-magnitude-based and cannot discern between normal traffic and high resistance electrical faults. Tests were conducted at cooperating mines to assist in developing a neural-network-based detection algorithm for distinguishing between electrical faults and normal operation. The Fast Fourier Transform of the trolley rectifier current signature served as baseline data for the neural network. During field tests, the algorithm performed with greater than 90% accuracy.

By E. William Rossi, Sean Gallagher, Richard L. Unger

The purpose of this study was to examine the lifting capacity of low-seam coal miners in four restricted work postures (roof heights of 36", 40", 44", and 48"), investigate the associated metabolic costs, and to examine electromyographic (EMG) data from eight trunk muscles during the lifting procedure. Subjects were thirteen underground miners accustomed to handling materials in restricted work postures. Each subject performed two twenty-minute periods of asymnetric lifting in each of four postures during the day of testing. The. frequency of lifting was 10 lifts per minute. A specially designed lifting box incorporated microswitches in one handle of the box and another in the bottom of the box, in order to examine the trunk muscle function at specific points during the lfting cycle. The data collected will be used by the Bureau of Mines to make recommendations for lifting materials in low-seam coal mines.

By E. V. Cilento, K. A. DiGregorio, R. C. Lantz

This laboratory has developed a sensitive electro-optical method to quantify the initial rate (R) and total amount.(MAX) of superoxide (SO) produced by single pulmonary alveolar macrophages (PAM). The method uses a microscope to visualize PAM in culture, and to video record the images during the time the cells produce SO. MAX and R are calculated from measurement of temporal changes in optical density in the images due to precipitated diformazan formed by the reaction of SO, produced by each PAM, with nitroblue tetrazolium present in the culture medium. To date, values of Rand MAX, measured due to adherence of PAM to the dish, have been compared to values obtained when quartz, coal mine dust (CMD), and kaolin were added to the medium (in vitro). R and MAX have also been calculated for PAM lavaged from animals exposed to quartz and CMD in the WVU Inhalation Facility. Presently, experiments are being done using serum which permits PAM to be restimulated by different dusts to help establish a dose response effect, and a means to study the effects of lung surfactant on modifying the toxicity of inhaled dusts. Long term, this methodology should provide useful insight· into establishing the role SO plays in the phagocytosis of inhaled dusts and bacteria, in PAM dysfunction, and in lung diseases such as pneumoconioses. Supported by the Department of the Interior's Mineral Institute Program administered by the Bureau of Mines through the Generic Mineral Technology Center for Respirable Dust (G1135142).

Jan 1, 1988

To provide a practical method to reduce hand and arm injuries during roof bolting operations.

Jan 1, 2000

The NIOSH Office of Mine Safety and Health has released communication products about flyrock safety in the form of informational brochures, flashcards, and toolbox talk materials. Both the mining and construction industries are targeted with these helpful communication tools. These new products can be used as refresher training for employees and as introductory safety materials for onsite visitors.

Dec 1, 2006

By K. L. Cashdollar

A project to evaluate the South African bagged stone dust explosion barrier was successfully completed at the National Institute for Occupational Safety and Health (MOSH), Pittsburgh Research Laboratory's (PRL), Lake Lynn Experimental Mine (LLEM) during the period November 1999 through May 2000. The tests were conducted in a three- entry section of the LLEM. Two types of explosions were used to evaluate the distributed and concentrated bagged barrier performance in a multi-entry mine section. The fuel zone of the first explosion type was only in the center B-drift. In the second explosion type, coal and stone dust mixtures were place in all three drifts. A total of six explosions, including two baseline and four barrier evaluation explosions, were conducted. Of the four barrier explosions, the distributed and concentrated barriers were each evaluated against the two explosion types. For these explosion tests, the distributed barrier extended from about 74 to 170 m and the concentrated barrier from about 74 to 104 m in B-drift. The distributed barrier successfully stopped flame propagation in both types of explosion tests. The flame extended further for the explosion tests where the dust was loaded in all three entries compared with dust loaded only in the center entry% but in both cases the flame was stopped within the barrier zone. The concentrated barrier was also successful in stopping flame propagation m both explosion tests. From the full-scale experimental mine test results, it can be concluded that both bagged barrier designs were effective in stopping coal dust explosions in the multiple entries of the LLEM.