Search Documents

By V. F. Parry

The major industrial uses of char or semicoke produced by low-temperature carbonization of coal4/ are as fuel for generating electric power, for blending with metallurgical coking coal as a substitute for low-volatile coals, and for gasification to produce synthesis gas for chemical purposes. This paper discusses various methods for carbonizing coal, emphasizing processing of the noncoking coals to produce char for thermal power-plant fuel and for blending with metallurgical coking coals and tar for chemical use. Low-temperature carbonization is a relatively simple processing step involving heating coal to about 900° to 1,200° F. to decompose the coal into 4 main products: (1) Semicoke or char; (2) complex, partly oxygenated liquid hydrocarbons or tar; (3) fixed gases; and (4) water. If the coal is heated rapidly under conditions that prevent decomposition of the primary products, 68 to 87 percent of the net heat in the raw coal is left in the char and 10 to 23 percent of the potential heat appears in the primary tar. Fixed gases represent approximately 7 percent of the heat and approximately 2 percent is lost or dissipated in the reactions of decomposition. Considering the different ranks of coal in the United States, the yield of tar will vary from about 9 to 44 gallons per ton, therefore it is important that each coal be carefully considered if it is to be carbonized for industrial use.

Jan 1, 1955

By Robert E. Barieau

General expressions for evaluating various thermodynamic properties applicable to the van der Waals equation of state have been derived. These formulas were subsequently used to evaluate various thermodynamic functions in the two-phase region. The results indicate that, for a van der Waals fluid, there is a finite discontinuity in the second derivative of the vapor pressure curve, in the second derivative of the chemical potential or Gibbs free energy at the critical point, and in the heat capacity at constant volume measured at the critical density. Numerical values are tabulated and graphs are presented for all functions calculated.

Jan 1, 1967

By Clarence Hall, J. J. Rutledge

Many of the fatal accidents in coal mines have resulted from the Explosives used in Use of explosives for breaking down the coal. These accidents have resulted both from the use of explo- sives that were not suitable and from the careless or improper use of suitable explosives. Investigation has shown that one of the commonest causes of dis- astrous explosions in the coal mines in this country has been a blown- out shot of black blasting powder or dynamite. The dangers that attend the use of these explosives were perceived several years ago, and in consequence the attention of powder manufacturers was directed to the production of explosives that would be less liable to ignite inflammable gas or dust. The manufacturers have been so successful in their efforts that it is now possible to obtain explosives which yield much shorter and quicker flames than black blasting powder or dynamite, and hence are much less dangerous to use in fiery or dusty coal mines. of explosives. To find out which of the many grades of short-flame explosives Government tests have the qualities that render an explosive most effective and least dangerous for mining coal, the United States Government established a testing station at Pitts- burgh, Pa., in 1908. This station is now under the charge of the Federal Bureau of Mines. Before the station was opened a state- ment of the requirements that the explosives in question would have to satisfy was drawn up and sent to manufacturers. A number of these sent explosives to be tested, and on May 15, 1909, a list of the explosives that had passed the tests was published. Since that date other brands of explosives have been tested and three more lists have been issued. The latest list, published in Miners' Cir- cular 2, Bureau of Mines, contained the names of no less than 71 explosives that had passed the tests prior to January 1, 1911.

Jan 1, 1912

By Robert D. Ewing

The computer program described in this user's guide provides for the static, three-dimensional, linear and nonlinear analysis of structural and geological systems by the finite element method. The guide describes the capabilities and general features of the program and shows how input is prepared. A number of recent advances in finite element theory and computer technology are incorporated in the program. Nonlinear material properties are provided for, including isotropic, anisotropic, and time-dependent material properties, gravity loading, simulation of a sequence of excavation or construction, and a slip or joint element. The finite elements include beam, rod, axisymmetric and plane quadrilateral, hexahedron, thick shell, and axisymmetric and plane joint. The program also has an automatic mesh generator to minimize user input preparation for continuum finite element meshes.

Jan 1, 1976

By F. E. Armstrong

A program with the objective of developing a fast, accurate instrumental method of analyzing mine dust for incombustible content has been underway in the Bureau of Mines for several years. Several prototype instruments making use of a gamma-ray backscatter technique have resulted. Although extensive laboratory testing has shown that these instruments are accurate under laboratory conditions, only extensive field testing will prove their ultimate practicality and usefulness. This report shows that under most conditions these devices are at least as accurate as the volumetric method and much faster in use. Other data obtained during the same study concerning mine dust are presented; these concern moisture content, sample bulk density distribution, and some particle size distribution information.

Jan 1, 1973

This volume contains a series of papers describing research conducted by the Bureau of Mines to develop or improve equipment and systems that satisfy the communication requirements of miners doing work related to rail, belt-conveyor, trackless, and hoist haulage systems.

Jan 1, 1977

By J. W. Davis

The storage stability characteristics of a diesel type fuel were determined to evaluate the effect of the polar compounds in the fuel. These compounds, comprising most of the nitrogen and oxygen containing compounds and many sulfur containing compounds, were separated from the fuel with a chromatographic column. This fraction was further separated into three polar extracts by graded elution through the column. Each extract was characterized. A storage program using the depolarized fuel, the fuel as received, and blends of the extracts with both fuels, was conducted. Results showed that the removal of the more polar components stabilized the fuel. Blending the polar extracts with the original fuel and with the depolarized fuel in the same ratio as they existed originally and at two and three times the original ratio increased the amount of gum present before storage, but had little effect on the formation of additional gum during storage. Distillate fuels produced by commercial refining of petroleum contain traces of organic nitrogen, sulfur, and oxygen compounds that are more polar4 than the remainder of the fuel. Recent laboratory studies by the Federal Bureau of Mines (1),6 in which these compounds were removed from a fuel, have shown that they influence its storage stability. The objective of this work was to determine the amount of these compounds present in a fuel and their effect upon its stability in storage. To evaluate the role of these polar compounds, it is necessary to remove them from the distillate fuel. Many can be removed by chemical treatment (2), but such treatment precludes reblending the polar components to approximate the original fuel composition. Solvent extraction is free of some of the criticism of chemical treatment, but it is more difficult because of the complex mixture from which compounds must be removed.

Jan 1, 1961

By P. L. Woolf

Three trials with oxygen-enriched unheated blast air are described. The trials were conducted in the Bureau of Mines experimental blast furnace located in Bruceton, PA. The first trial utilized moisture addition to the oxygenated blast. The second and third trial were conducted with natural gas injection. The test was basically a feasibility study and in that regard the practice was demonstrated to be feasible and also have possible advantages over hot blast operation. The testwork was conducted in 1964 and 1965 as part of a continuing study of iron making technology in cooperation with several North American Steel Companies.

Jan 1, 1985

A new horizontal borehole packer for use in coal beds has been developed. This packer utilizes a principal of operation which has not previously been used. The resulting packer is less costly to purchase, can be easily repaired in the field with inexpensive expendable parts. This report describes the development and testing of the new packer and the evaluation of commercially available packers.

Jan 1, 1971

By J. S. Browning

Laboratory and pilot-plant tests of spodumene-beryl pegmatites of the Kings Mountain, N. C., area resulted in development of a new and improved method by the Bureau of Mines for separating and recovering spodumene, mica, and beryl. The process was successfully applied to other domestic pegmatites and a spodumene flotation-plant tailing containing about 0.5 percent beryl. The method comprised soap flotation of the spodumene, using combinations of sodium fluoride and lignin sulfonate as conditioning agents to recover 80 to 85 percent of the contained lithia in concentrates assaying over 6 percent Li20. About 80 percent or more of the beryl was retarded in the spodumene tailing. The beryl subsequently was activated, floated, and cleaned in a secondary circuit to yield beryl concentrates containing 6 to 7 percent BeO. The tests also demonstrated that a good recovery of high-grade mica could be produced.

Jan 1, 1961

By J. D. Brown

The electron optics, vacuum system, and sample stage assembly for the Bureau of Mines? electron probe X-ray spectrograph were purchased. Four scanning curved-crystal spectrometers, two reflection- and two transmission-type, were designed and constructed by the authors. The reflection spectrometers are placed in a vacuum chamber for measurement of long-wave-length X-radiation. Detection, pulse-amplitude discrimination, and recording circuits are provided for the simultaneous measurement of four X-ray spectral lines. Minimum spot size is approximately 2 microns in diameter at 30 kilovolts and a sample-to-ground current of 5 x 10-8 ampere. At this voltage and current the limit of detection with reflection spectrometers is less than 0.05 weight-percent for most elements. The limit of detection for elements determined by transmission-type spectrometers, evaluated at 35 kilovolts and 5 x 10-8 ampere, is approximately 0.1 weight--percent for all elements having excitation voltages below 20 kilovolts. In general, reflection spectrometers exhibited satisfactory but poorer resolution than the transmission type, resolution of the spectrometers being limited primarily by crystal imperfections, with greater mosaic structure being introduced by the grinding process for the reflection crystals. Several applications of the electron probe X-ray spectrograph are described. Analysis of a uranium-steel is discussed in detail to illustrate calculation of composition from measured X-ray intensities.

Jan 1, 1962

By A. C. Richardson

The mine of the Porter Coal Co. is located at the town of Porter in the northwestern part of Jefferson County, Ala., about 20 miles west of Birmingham. The operations in this mine are confined to the middle and bottom benches of the Mary Lee bed. The coal from the Porter mine is handpicked and washed before being placed on the market. The handpicked lump coal and the washed egg and nut coal are sold chiefly as domestic and steam-raising fuel. The coal finer than 1 inch is washed in 2-compartment jigs and utilized in the manufacture of metallurgical coke. The coal company has found that, when coal ranging in size from 1 to 0 inch is washed in jigs, a considerable amount of high-ash material finer than 3/16 inch remains in the washed coal. This paper gives the results of an investigation which was conducted for the purpose of determining the washing characteristics of the through 3/16-inch raw coal and the extent to which the ash might be reduced by means of coal-washing tables. This investigation has been made in connection with an extensive study of the coal-washing problems now being conducted by the United States Bureau of Mines and the University of Alabama, with the cooperation of the coal-mining companies of the State.

Jan 1, 1933

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

"DIGREGORIO, K. A., E. V. CILENTO, AND R. C. LANTZ. A kinetic model of superoxide production from single pulmonary alueolar macrophages. Am. J. Physiol. 256 (Cell Physiol. 25): C405-C412, 1989.-A kinetic model was developed to describe the production of superoxide (02) by single pulmonary alveolar macrophages (PAM). Model predictions were compared with experimental results obtained from single rat PAM. The 02 was quantified by measuring the reduction of nitro blue tetrazolium (NBT) to a diformazan precipitate (NBTH,) from video-recorded images of individual cells. The kinetic model considered three reactions: 1 ) the production of extracellular 02 from the reduction of oxygen by NADPH oxidase using intracellular NADPH as the substrate, 2) the subsequent dismutation of 02 to form H,O,, and 3) the reaction of 02 and NBT to form diformazan. NBT specificity for 02 was analyzed by comparing results in the presence and absence of superoxide dismutase (SOD) that catalyzes the dismutation of 02 to H,O,. Measured PAM heterogeneity was accounted for by varying the concentration of intracellular NADPH, its rate of depletion, and the concentration of intracellular NADPH oxidase in the kinetic model. Model predictions compared favorably with experimental results except when SOD was present. This discrepancy may be due to diffusional limitations because NBT is a relatively small molecule (818 mo! wt) compared with SOD (34,000 mol wt). In addition, the cell surface is both ruffled and negatively charged, which may introduce steric hindrances and/ or electrostatic effects, since SOD is also negatively charged, whereas NBT is positively charged.PULMONARY ALVEOLAR MACROPHAGES (PAM) protect the lungs by phagocytizing foreign debris and bacteria. This process is accompanied by the production of superoxide anion (02) at the surface of the plasma membrane (3, 31). Superoxide readily dismutates to form H20 2 and subsequently, other oxygen metabolites which have been shown to be both antibacterial and cytotoxic (21, 25, 35).Superoxide is produced from the reduction of extracellular O, at the surface of the cell membrane by NADPH oxidase by the following reaction (3, 4)"

Jan 1, 1989

By Nan C. Jensen, Oliver Bowles

"INTRODUCTION Limestone (which consists essentially of calcium carbonate) and dolomite (calcium magnesium carbonate) occur widely in the United States. Their presence is of vast economic importance, because they are used much more extensively than any other form of rock. In 1945, limestone (which, broadly, includes dolomite) was quarried in every State except Delaware, New Hampshire, North Dakota, and Rhode Island, and also in Hawaii and Puerto Rico. Total production (including that used in cement and lime manufacture) exceeded 151,700,000 tons, or 79 percent of the quantity of all kinds of stone sold or used during that year.Important well-known uses of limestone are as concrete aggregate, road material, railroad ballast, for liming the land, for cement manufacture, as riprap for shore protection, harbor work, and spillways at dams, and as building stone.. None of these uses, however, are considered herein. The purpose of this paper is to discuss the industrial and chemical uses that are less widely known and yet are of tremendous importance in a great variety of processing industries. Important examples are dolomite as a refractory furnace lining and limestone as a fluxing agent in blast furnaces, and as a raw material employed in sugar, paper, glass, and alkali manufacture.PRIOR REPORTIn May 1941, the Bureau issued a report 4/ that described these uses in some detail. As new and important developments have taken place during the ensuing years, a revision and representation of the salient features of these uses seem desirable. Asphalt filler and mineral wool uses included in the earlier report are omitted from this paper because they are identified more closely with the highway and building industries, respectively, than with the industrial applications."

May 1, 1947

By Victor Spironello

The Bureau of Mines is studying cupola ironmel technology with the objectives of conserving high-quality raw materials through substitution and productivity. In the research re-ported here, a ize was modified by a gas-fired melting and/or ing chamber into the stack above the level of the coke bed, for study as a prototype for a coal-fired melting chamber. The modified cupola, in which natural gas was used to partially replace foundry coke, was evaluated in several trial runs. Data were obtained on furnace performance, metal and slag chemistry, and scrubber waters as particulates. Results of the modified ion were compared to those of conventional cupola operation. Although this research was preliminary--since the ultimate goal is to use pulverized coal instead of yielded ample evidence that the melting rate of a cupola can be icantly increased with less than a increase in energy input. Other evidence suggests that melting of low-density scrap can be enhanced and that scrap containing undesirable and/or oxidizable elements can be appreciably upgraded. This work is continuing and will include the use of pulverized coal of low rank to assist in melting.

Jan 1, 1984

By Alfred L. Ransome

The plan to develop a standard system of names and definitions of regions and districts in Alaska was borne of the need for a tool to use in statistical and economic studies of the mineral industry of the Territory. The purpose of this report is to present to the mineral industry, and to those individuals interested in the mineral or allied industries in Alaska, the system used by the Bureau of Mines in connection with its legal function of collecting and disseminating mineral statistics. It is hoped that the specific descriptions given will result in a more complete understanding of what is meant by the regional and district names that appear in publications of the Bureau of Mines relative to the mineral industry of the Territory. Problem of Standardization of Names and Definitions The question might be asked, does the naming and defining of regions and districts in Alaska present a problem relative to the establishment of a standard? Is it necessary to establish a standard?

Jan 1, 1954

By C. Golumbic

Most early research on solvent extraction of coal has been concerned with the molecular structure of coal. Although rush work is continuing, practical aspects of the subject also are being emphasized. For example, development of the Pott-Broche extraction process resulted from the discovery of very efficient solvents for the pressure-extraction of coal. Recently, Orchin and Storch reported the use of even more efficient solvents under similar conditions. In addition to the discovery of more effective solvents, the possibility of efficient extraction at atmospheric pressure is obviously of practical interest. H. J. Rose observed that phenanthrene at its atmospheric boiling point readily dispersed 80 percent or more of Pittsburgh-bed bituminous coal. This fact served as the starting point of the present investigation, ill which determination of the chemical specificity of this solvent and the chemical nature of the resulting extracts was undertaken. This paper represents a progress report of the results obtained to date.

Jan 1, 1950

By A. L. Engel

In previous reports5/ of ore-testing studies, tests made by established methods on typical ores selected as representative of certain mining districts have been described in considerable detail. In addition to established test procedures, such as screen analysis, chemical analysis, microscopical examination of ores and products, sink-and- float separation, gravity concentration, flotation, ,and magnetic separation with or without roasting, it was sometimes necessary to apply other methods, such as leaching, in instances where physical separations were not feasible.

Jan 1, 1940

By A. L. Engel

In previous reports5/ of ore-testing studies, teats made by established methods on typical ores selected as representative of certain mining districts have been described in considerable detail. In addition to established test procedures, such as screen analysis, Chemical analyses, microscopical examination of ores and products, sink-and-float separation, gravity concentration, floatation, and magnetic separation with or without roasting, it was sometimes necessary to apply other methods, such as leaching, in instances where physical separations were not feasible.

Jan 1, 1940

By R. W. Stahl

"This study by the Federal Bureau of Mines was confined to pillaring with continuous mining machines and to mines where total extraction is practiced. Many different conditions and practices in as many coalbeds as possible in Pennsylvania were observed.Pillar extraction or pillaring can be the most productive part of coal mining if done properly; but it also can be the most dangerous if done improperly.Because of the need for more careful planning before and caution during pillaring, many mining companies resort to the undesirable practice of stumping or hogging of pillars with subsequent unnecessary waste of valuable natural resources. Pillaring can be done at reasonable cost and safely, as proven at many mines where complete extraction is practiced and enviable cost and accident records are maintained.Although continuous mining machines are bulky and sometimes difficult to maneuver, they have been used with great success in pillaring. Occasionally, however, a machine is caught, or men are injured by a fall during pillar recovery. This Bureau survey was conducted to ascertain how safe and successful pillaring (especially the removal of final stumps in lifts or the final stump of a pillar), is accomplished in some mines, while others have considerable difficulty under similar conditions.The Bureau hopes the information to be presented in this publication will prove beneficial to those who wish to recover more pillar coal and to improve their accident record during such procedures."

Dec 1, 1959