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By E. J. Gleim

A study of the records on file in the Bureau of Mines reveals that moray fire in coal mines have been started by electrical equipment or circuits. There the fires were of undetermined origin, electricity often was Strongly suspected as the probable cause. While it is unfortunate that positive evidence as to the cause is so often lost in the general destruction resulting from fires, there are many lessons to be learned from fire s in which the origin was definitely established as electrical. For modern high-speed methods of producing coal, electrically operated machinery has become virtually indispensable underground. With increases in the amount of equipment it has not always been necessary to increase the number of circuits in the mine where direct current is mainly used, but it has been necessary to increase the carrying capacity of these circuits. For example, lends such as heavy-haulage units drawing 1,000 amperes or more have brought boat the introduction of 6/0 and "No. 9 section" trolley wires. This has not made the task of fire prevention any easier, for it has meant that circuit breakers s must be set so high that partial short circuits fail to open them, therefore an arc of considerable proportions can be maintained without causing the, beaker to open. Thus, if as fall of roof brought a trolley wire down against a loaded car of coal, an arc might be struck that would ignite they cowl without opening the circuit breaker.

Jan 1, 1937

By J. B. Gayle

The Bureau of Mines studied the effects of air oxidation on the recovery of float coal. Both batch-and continuous-type tests were made on six bituminous coals, representing the range in rank of coals now commercially used for carbonization, and on one anthracite coal. The effects on flotation recovery of oxidation at 1000 C for periods up to 50 days were investigated using an alcohol-type frother and a kerosine-pine oil reagent. Two series of release analysis tests were made, using one medium-volatile bituminous coal. Float coal recovery was adversely affected by oxidation in all tests where the alcohol-type frother was used. Conversely, a small degree of oxidation improved recovery with kerosine-pine oil frother for some of the coals in continuous tests. Prolonged oxidation (beyond about 14 days) adversely affected float coal recovery for all coals, the effect being more pronounced for batch-type tests and for tests using alcohol-type frother. Reagent selectivity for the rejection of both ash forming and sulfur bearing minerals was reduced by oxidation. Severe reduction of reagent selectivity required only about 3 days' oxidation for alcohol-type frother but more than 10 days' oxidation when the kerosene-pine oil reagent was used.

Jan 1, 1965

By G. S. Scott

In the course of tire investigation into the causes, behavior, and control of mine fires, which the Bureau of Mines is now conducting, come attention was given to the subject of spontaneous heating. It is self-evident that the temperature of a pile of broken coal will rise if the rate of generation of heat exceeds the rate of heat dissipation and will fall if the opposite is the cane. Factors that affect the rate of generation of heat are:

Jan 1, 1941

By Edward Keller

The work covered by this report was undertaken at the request of Dr. J. A. Holmes, late Director of the Bureau of Mines, to whom the writer had been recommended by C. W. Goodale and E. P. Mathewson, of Butte and Anaconda, Mont. The director's offer was accepted for the honor it conferred and for the useful results that might be promulgated by the work in the technical field covered. The investigation was facilitated by permission to visit various works and sometimes by contributions of important definite information on a given subject. It is therefore with pleasure that acknowledgment of courtesies is made to the following corporations and gentlemen: Anaconda Copper Mining Co., Raritan Copper Works, Baltimore Copper Smelting & Rolling Co., United States Refining Co., American Smelting &, Refining Co., B. B. Thayer, A. C. Clark, A. L. Walker, William H. Peirce, E. A. Cappelen Smith, H. H. Alexander, F. C. Newton, S. Rolle, R. W. Deacon, N. W. Pierce, O. C. Martin, C. N. Sappington, James K. Thomson, W. G. Derby, and the assistants of the writer, K. W. McComas and W. L. Raup. In this report considerable space has been devoted to general and theoretical principles on the ground that under modern conditions the best results in any field of activity can be attained only with the a. id of an adequate knowledge of the best theories underlying the practice. The diffusion of such knowledge in the field of sampling metallic metallurgical materials appears to have been quite insufficient, and it is felt that when the principles involved are once thoroughly comprehended their universal application will be appreciated, so that it will make no difference whether pig iron or gold bullion is offered for test. It may further be noted that a discussion of the theories underlying practical methods is placed under the caption "Practical Sampling," with the idea that no one can be a practical sampler unless he is capable of analyzing his methods. No attempt has been made to advocate any one method, but it is hoped that the analyses of all of the methods in use will show where each may be correctly and safely applied. The fact that it is possible to demonstrate the theoretical correctness of several methods indicates the invalidity of the claim that any single one of them is the standard.

Jan 1, 1916

By H. F. Yancey, E. Zane

"INTRODUCTION The term ""friability"" as applied to coal may be defined as the physical property of coal which expresses its tendency to become reduced in size during handling as a result of such external forces as impact and attrition. Thus friability is a quantitative concept and property, and hence can only be defined in relative terms or in terms of measurement. Methods of measurement are difficult to formulate and apply because coal is anything but homogeneous in physical structure and chemical constitution. aMoreover, friability itself is a composite property obviously dependent upon a group of other specific characteristics such as cleavage, fracture, tenacity, hardness, and elasticity, which vary from coal to coal with change in rank and even between individual coals of the same rank. These characteristics affect the friability values of different coals to varying degrees, but this fact does not impair the usefulness of and the need for friability measurements.The amount of breakage or degradation in size that a coal suffers in mining, preparation, and subsequent handling depends upon its inherent friability and the severity of the handling treatment which it receives from the time it is taken from the bed until it reaches the consumer. The value of the coal to the producer and jobber depends in large measure upon these same factors--friability and severity of treatment—because the larger sizes still command a premium in the ordinary market. Although much has been accomplished by the coal-producing industry in minimizing the breakage of coal in mining and preparation, it is apparent that additional reductions in breakage must await further improvements in design of coal-handling equipment. Such improvements will result from more intensive investigations of the extent of breakage or degradation in size occasioned by specific mining and handling operations and the development and application of standardized methods of evaluating friability.The work described in this report was undertaken to assist in the development of standard methods for evaluating the friability of coal. Specifically, the work deals with a Comparison of the various methods previously proposed for estimating the friability of coal and coal products. This same objective is now being sought at a number of other institutions, both in the United States and Canada, by a committee of the American Society for Testing Materials. It is believed that by providing additional information concerning a property of coal pertinent to its increased usefulness, the work described will supplement and increase the useful of the data which long have been, and still are being, furnished by the bureau of Mines on the composition of coals of the United States."

Jun 1, 1933

VOLUME I Volume I of this three-volume report is the result of development of a comprehensive, coordinated approach to site data-acquisition activities to produce key plans and reports during the evaluation and development of a surface coal mine. A logic diagram illustrates activities in the planning and decision-making process from exploration through post-mining monitoring. The report briefly discusses major elements, other than the site environment, which influence development of mining and reclamation plans and refers to other readily available literature for details outside the scope of this study. The essence of the rationale is shown to be the 1 employment of necessary skills at the proper time to evaluate specific data ' requirements and integrate them into a cost-effective program to produce initial and major feasibility reports, mining, and reclamation plans, and the environmental impact assessment.

Jan 1, 1976

By Arno C. Fieldner, J. W. Paul, WALTER A. SELVIG

Many mine samples of coal are analyzed each year in the laboratories of the Bureau of Mines. The analyses are made in connection with investigations relating to fuels belonging to or for the use of the United States Government, the causes of accidents in coal mines, the geologic relations of coal beds, and the quality and the value of the coal and lignite in the public lands. The systematic collection and analysis of such samples in connection with fuel investigations was begun in 1904 at the Government fuel-testing plant at the Louisiana Purchase Exposition. and was under the direction of the United States Geological Survey for six years. Descriptions of the coal samples collected between the beginning of this work, July 1, 1904, and the transfer of the fuel-testing and mine-accident investigations to the Bureau of Mines,July 1, 1910, were compiled and published in Bureau of Mines Bulletin 22.' Descriptions and analyses of samples collected during the fiscal years 1911 to 1913 were published in Bureau of Mines Bulletin 85.2 Descriptions and analyses of samples collected during the fiscal years 1913 to 1916 were published in Bureau of Mines Bulletin 123.3 The present bulletin presents analyses and descriptions of samples collected during the fiscal years 1916 to 1919. In order that the material in this bulletin may be used to supplement that presented in Bulletins 22, 85, and ,123, the same plan of geographical classi- fication has been followed, the analyses and descriptions of the samples being grouped in alphabetical order according to the State, county, and town near which the mines or prospects sampled are situated.

Jan 1, 1922

By W. E. Tournay

In accordance with a cooperative agreement between the Bureau of Mines, United States Department of the Interior, and the Linde Air Products Co., an investigation was made at the Bureau Explosives Testing Station, Bruceton, Pa., to develop suitable test methods for evaluating the performance and sensitivity characteristics of liquid-oxygen explosives. This report presents the results of the investigation. The unique nature of liquid-oxygen explosives necessitated both modification of standard techniques and development of entirely new test methods. The latter requirement was due to the fact that differences exist in the kind of information that must be developed for studying relative safety and performance properties of these explosives compared to that of fixed explosives.

Jan 1, 1949

By T. E. Swigart, C. E. Beecher

The Federal Government, as the largest lessor of oil and gas lands in the United States, is vitally interested in the conservation of those resources. This manual has been prepared at the direction of the Secretary of the Interior to call the attention of lessees of public oil and gas lands to the most common oil and gas field wastes and the best methods of preventing them; to outline the policies of the Interior Department on field operations; and to give information as to how the "Operating Regulations" of the department will be interpreted by the Bureau of Mines. The oil industry has progressed steadily. Present operating methods are much more efficient-and less wasteful-than those of a few years ago; moreover, the art of producing oil and gas is continually advancing. Public interest requires that improved methods, which will result in obtaining the greatest possible amounts of oil and gas from the natural deposits, shall be developed and used. Part I of this manual points out types of oil and gas wastes and suggests, in detail or by reference, the most practical and effective methods in current practice for stopping these wastes. Throughout Part I the department's operating policy is given, with interpretations of the "Operating Regulations" for enforcing every practical measure of conservation. Part II comprises the revised "Operating Regula-tions" which supersede all previous regulations and will govern future operations on public lands; it will be found in the pocket in the back cover of this bulletin.

Jan 1, 1923

By Serge Rudchenko

A study to determine the potential use of retaining structures in open pit backfilling. Research and review of the open pit mine environment, mine waste disposal, and past and current use of retaining structures. A development of specific structures, the culvert/ tunnel concept, and an anchor block retaining concept. The cost benefit of retaining structures used for in-pit backfilled waste.

Jan 1, 1981

By Lowell Stroud

Since 1929, the Helium Activity of the Bureau of Mines has operated a helium-extraction plant at Amarillo, Tex. The natural gas that supplies this plant is obtained from the Cliffside geologic structure 12 miles to the northwest and over the years, has become known simply as "Cliffside gas," There is need for published data on the low-temperature phase equilibria of helium-bearing natural gases. To date, little information has been published on the equilibrium phase compositions, solution of helium in condensed natural gas, condensation characteristics, or equilibrium vaporization coefficients for methane, nitrogen, and helium in helium-containing systems. A windowed phase equilibrium apparatus (8)6 was used to obtain 105 equilibrium samples, representing 35 experimental conditions of condensed Cliffside gas at pressures of 100, 200, 300, 400, and 500 p.s.i.a. and temperatures from 0° to -270° F. Data on equilibrium vapor-liquid composition for Cliffside gas are presented in both tabular and graphic form and are discussed in detail to show their relationship to certain criteria that must be met to effect an efficient separation of helium from natural gas by means of low-temperature processes. Facts about condensation characteristics and solution of helium in the liquid phases are included, The important relationship of these two factors in decreasing the percentage of total helium lost by solution in the liquid phase is discussed.

Jan 1, 1961

By D. Harrington

A uniform hoisting-signal code for mines hoisting from more than one level, if adopted by all mining States, would be beneficial to employees and owners alike and should largely reduce the number of hoisting accidents. Misunderstood hoisting signals cause many shaft accidents involving injuries to men, damage to equipment, and loss of production from the resultant delay. Many of the metal-mining States have adopted codes for hoisting that are effective within the borders of that State but usually entirely different from the signal code, if any, in use in an adjoining State. For many years safety engineers have recognized this lack of uniformity as a distinct hazard, but a uniform code has never been adopted by the States or by the mining industry in those States that have not incorporated signal codes in their mining laws or mining regulations.

Jan 1, 1944

By Winton Gale, David Oyler, Jinsheng Chen, Christopher Mark

The National Institute for Occupational Safety and Health’s (NIOSH) Pittsburgh Research Laboratory (PRL), RAG Pennsylvania and Strata Control Technologies of Australia have collaborated to conduct an extensive study of roof bolt strata interaction at the Emerald mine in Southwestern Pennsylvania. The primary goal of the project was to obtain detailed data on the interaction between the mine roof and the support elements for use in modeling studies. The study site was a longwall tailgate subjected to high horizontal stress. Three arrays of instruments were installed at the site, one in the tailgate entry and two in an adjacent crosscut. Pumpable concrete cribs were present in the tailgate array, and cable bolts were installed in one of the crosscut arrays. The instruments included mechanical and sonic extensometers for measuring roof movement, instrumented roof bolts, and three-dimensional roof stress cells. The study was ultimately successful in determining the magnitude of the horizontal stress concentration, the height of roof failure and the roof failure sequence, and the loading history of the primary roof supports.

By E. W. Dean, H. H. Hill

Gasoline has become of such commercial and military importance that it is now practically indispensable. This product is of special interest because, in addition to realizing its value, the Nation is learn- ing that the raw materials from which gasoline is obtained are not unlimited. ACTIVITIES OF THE BUREAU OF MINES IN PROMOTING EFFICIENCY IN THE PRODUCTION AND UTILIZATION OF GASOLINE. The Bureau of Mines has directly and indirectly worked for the conservation and efficient utilization of this important product. Some of the bureau's activities have been along lines widely different from those reported in this bulletin. The work of the bureau toward the increase in efficiency of processes for the production and refining of crude oil is too well known to need mention here. Another line of activity in which the bureau has engaged is the collection and publi- cation of statistics on refinery operations. Finally, as immediate preparation for the present bulletin, two surveys of the gasoline mar- keting situation have been made. The primary object of this bul- letin is to make available to the public information obtained in con- nection with these surveys. PURPOSE OF THE GASOLINE SURVEYS OF 1917 AND 1919. Shortly after the United States declared war on Germany the bureau collected gasoline samples in the retail market throughout various parts of the country. Information regarding the sources of these gasolines and the details of marketing them was obtained, and they were subjected to analytical tests which furnished conclusive informa- tion regarding their properties. The information obtained through this survey proved of inestimable value both to the bureau and the United States Fuel Administration, particularly in drawing up speci- fications and in ascertaining the best means of obtaining supplies of particular types of gasoline that were needed. A similar and more extensive survey was made in the months of April and May, 1919, in order to obtain data needed for the revision of the Federal motor gasoline specification. The specification adopted during the war had been the subject of numerous complaints, and it seemed desirable to determine whether or not these objections were valid before attempting revision.

Jan 1, 1920

By Jeffery L. Kohler

This final report on Bureau of Mines Contract J0338028 presents the results of a research effort to predict incipient failure in electric-power-system components. The development of continuous monitoring techniques to detect an incipient failure would represent a significant improvement in system maintainability, availability and safety, This report describes the analytical and experimental aspects of the project. Mathematical models have been developed to study the behavior of cables and motors which are undergoing a deterioration process. These models allow a detailed study of the effect of deterioration on the component's terminal characteristics and performance. The efficacy of using negative-sequence monitoring is a reliable indication of deterioration has been established. Techniques for assessing the sensitivity of the prediction algorithm to component deterioration have been presented. An approach for modelling electrically-excited vibrations, and including these in the algorithm, has been presented.

Jan 1, 1987

By James L. Elder

The Bureau of Mines and the Alabama. Power Co. jointly conducted a first experiment in underground gasification of coal at Gorgas, Ala., during the fall and winter of 1946-47. This preliminary experiment showed that it was not difficult to maintain combustion of coal underground, and that coal in place could be completely gasified. It was noted that the high temperature developed by the gasification of coal in place brought about changes in overlying strata that appeared to be favorable to the process. The high temperatures caused the roof rock to become plastic, to expand, and to settle down on the mine floor directly behind the reacting coke face. These results were promising enough to warrant further investigation of the process. It was believed that if this action could be controlled properly with roofs of similar composition, it would tend to force the gas-making fluids underground against the coal faces. Plans for the second experiment were based in part on this favor-able roof action, and the successful operation of the planned initial straightline passages depended on this fact. Gorgas was chosen as the site for the second experiment for the following reasons: A tract of coal land of sufficient size was available and isolated from the main body of coal; the roof rock was similar in composition to that encountered in the first experiment; and the overlying strata were thick enough to eliminate some of the operating difficulties that had been encountered, In addition, power, water, and machine-shop facilities as well as an adequate supply of labor were available in this area, and the friendly cooperation of the Alabama Power Co. further recommended this site for the planned experiment.

Jan 1, 1951

By R. E. Chaney

This report summarizes the research on the Strategic and Critical Materials Program tasks conducted at the Idaho National Engineering Laboratory (INEL) between Mdy 1983 and April 1984. The work is divided into two areas: 1. Production Technologies - Tasks directed at developing advanced extraction technologies ? Biologically-Assisted Minerals Processing ? Metal/Gas Reactions and Thermal Plasmas ? Dehydration of Aluminum Chloride Hexahydrate. 2. Conservation/Substitution Technologies - Tasks directed toward establishing the technical processing base which will permit the use of advanced materials ? Joining of Rapidly Solidified Alloys (RSA) ? Joining of Silicon Nitride-Based Ceramics ? Nondestructive Evaluation of Ceramic and RSA Joints and Materials.

Jan 1, 1984

By Howard F. Carl

"INTRODUCTION Talc is a hydrous magnesium silicate mineral found throughout the world in deposits of economic importance. This mineral occurs in different physical forms and varying degrees of purity, both of which affect its ultimate commercial usage. Talc is used in finely ground condition by the ceramic, paint, paper, rubber, cosmetic, and other industries. Most domestic talc production is of this type. Talc also occurs, although much less frequently, in massive, fine-grained, fairly homogeneous bodies; the impure varieties are the familiar soapstones, and the purer form is frequently called ""steatite."" Because of certain properties, the purest grades of this massive variety have a monetary value about 20 times that of the ground talc.One desirable property of this massive talc is its amenability to accurate cutttng, machining, and working in many ways, similar to a hard wood or soft metal, and then firing without warping or appreciable shrinkage into a hard, refractory ceramic body. Consequently, shapes that cannot be formed conveniently by molding and pressing can be produced readily with ordinary machine tools. When talc is fired to about 1,100° C., it is converted to a ceramic body with certain very desirable physical properties. This fired material has a hardness and toughness frequently superior to steel. It is a refractory and an exceptionally good electrical insulator. When formed from a high-grade talc essentially free from iron, it has unusually low dielectric losees, even at very high frequencies."

Feb 1, 1945

The design, specification, and performance evaluation of the Communications and Location portions of a Coal Mine Rescue and Survival System are described. The work was performed as part of a nine month effort to develop a mine rescue and survival system using existing technology and state -of-the -art hardware as recommended by the National Academy of Engineering. Three basic subsystems were developed, one for survival, one for communications/location and one for rescue. This report and related equipment manuals describe only the Communications/ Location Subsystem which was designed, fabricated, and tested by the Westinghouse Georesearch Laboratory in Boulder, Colorado. Two basic technologies were used. Electromagnetic signals propagating through-the-earth provide voice downlink and coded beacon up-link communications. Seismic methods were developed to provide means for locating trapped miners. Seismic signalling also provides a backup means for communications. Parallel development programs for the electromagnetic and seismic portions of the system were conducted. The resulting hardware and software have been partially tested in coal mines and under simulated emergency conditions in order to evaluate system performance. The results of these tests are discussed. Further testing is recommended in order to establish quantitative performance limitations tinder a variety of environmental conditions and to develop methods for improving system performance.

Jan 1, 1971

By F. E. Brantley

Research was undertaken by the Bureau of Mines to assess the technical feasibility of smelting cement-copper precipitate in an electric furnace to produce commercial-grade copper. The blister-grade copper produced in smelting was refined by gaseous oxidation and reduction methods to rive a product equal in quality to fire-refined copper. The cement copper used in the study was typical of the material produced in commercial operations. The sample product was received in a partially oxidized state and analyzed 77.5 percent Cu, 3.4 percent Fe, 0.8 percent Pb, 0.05 percent Ni, 0.6 percent Sn, and 0.9 percent S. Smelting tests were made on the precipitate using laboratory-size induction and electric-arc furnaces. Three types of furnace linings were tested during, the investigation: Carbon, including graphite; clay-graphite; and silicon carbide. Although all proved satisfactory, either carbon or graphite was preferred because of their superior refractory properties and low permeability to molten copper. Copper recoveries in the induction and arc smelting tests averaged 92 percent in commercial-grade metal assaying 99.8 percent copper. Refining the molten copper by oxidation and gaseous reduction or by chlorine lancing increased the purity to plus 99.9 percent.

Jan 1, 1961