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By Forrest T. Moyer

In conjunction -with the statistical survey of the lime industr-.r in 1939, by the Bureau of Hines, producing companies reported the lime-fuel ratios attained in their plants according to type of kiln and kind of fuel. Each ratio, expressed as the number of pounds of lime burned by a unit quantity of fuel, was weighted according to the tonnage of quicklime pro- . duced at the reporting plant and grouped with similar data from other plants, so that an average ratio for each type of fuel and,kiln could be calculated. By this method the variables trat affect ratios of individual plants are more or less equalized, and the computed average lime-fuel ratios provide a fair measure of kiln and fuel efficiencies during 1939.

May 1, 1941

By S. J. Schatzel, P. W. Jeran, W. P. Diamond, F. E. McCall, F. Garcia, J. C. LaScola, T. P. Mucho

The National Institute for Occupational Safety and Health, Office for Mine Safety and Health Research, is investigating the geologic and mining factors influencing the migration of longwall gob gas. One goal of these studies is to optimize methane drainage strategies to reduce the volume of gob gas that reaches the underground workplace. As part of this research effort, longwall gob gas flow paths in a mine operating in the Pittsburgh Coalbed, PA, were investigated using SF6 tracer gas. Tracer gas released into the ventilation airflow underground generally stayed in the bleeder system and was vented at the associated bleeder fan shafts. Tracer gas injected into an inactive (intaking) gob gas venthole migrated to the two inby producing ventholes on the study panel, indicating that all three ventholes were in communication. The tracer gas that was injected into the gob generally stayed in the gob and only migrated to the ventilation system in response to the venthole on the study panel closest to the injection hole going off production. Tracer gas flow velocities in the longwall gob reservoir and factors influencing the production performance of gob gas ventholes in the study area are also discussed.

By L. C. IlsLey, R. A. Kearns

As the use of electricity becomes more and more general in mining opera- tions, interest in regulations governing its application becomes greater. During the past year the electrical section of the Bureau of Mines has made a study of State regulations now in force relating to the use of electricity in coal mines. Technical Paper 271, entitled "State Mining Laws on the Use of Electricity in and about Coal Mines", has been published as a result of this study. The present paper represents a compilation of all laws relating to accident prevention with respect to electrical circuits. This group of regulations is perhaps the most important of any that relate to safety in coal mines. Its importance is shown by reference to accident statistics in Bulletin 115, (Fay, A.H., Coal-Mine Fatalities in United States, 1870-1914, Bureau of Mines, 1916), which show that about 77 per cent of the fatalities due to electricity in and about coal mines were caused by direct or indirect contact with trolley or other power circuits. In actual number this means that of 710 men killed by electricity, 546 were killed by contact with electric wires. Undoubtedly, a large percentage of these accidents might have been prevented had the wires been properly guarded. The compilation follows:

Mar 1, 1921

This publication summarizes the Bureau's activities as part of a study of the Juneau Mining District (JMD) during the period 1984-1988. The objectives of the program were to identify the type, amount, and distribution of mineral deposits in the district, determine ore reserves, study beneficiation technologies for the ore, make feasibility studies, and address economic and legislative effects on mineral development. The JMD study was a cooperative study involving the Bureau and the Alaska Division of Geological and Geophysical Surveys (ADGGS). Over 30 employee-years were spent by the Bureau on this project. Bureau investigations in the JMD consisted of a district-wide investigation of industrial materials in addition to site-specific investigations of precious and base metals in five subareas. During the 4 years of the JMD study, more than 300 areas, mines, prospects, and occurrences were visited, which contain gold, silver, copper, zinc, lead, nickel, cobalt, tungsten, molybdenum, chromium, and platinum group metals (PGM). More than 59,000 feet of underground workings were mapped and sampled. More than 5,500 samples were taken; one diamond drilling program and three geophysical surveys were completed. An up-to-date and complete mineral data base for the JMD did not exist prior to this study. The JMD study, which coincided with a tremendous increase in mineral interest and activity in the district, has proven to be valuable to both the minerals industry and land management agencies. The discovery of two new mineral occurrences and compilation of data on known mines, prospects, and occurrences have aided industry activity in the region. The study enabled timely data to be available to land management agencies at the Federal, State, and municipal levels.

Jan 1, 2012

By Doris M. Hyde

New mineral activity focused on increased petroleum exploration activities, while the established construction-oriented minerals sector operated without substantial change from previous years. After showing a 1 % real growth in the $154 million II gross domestic product (GDP) for 1983, preliminary estimates for 1984 indicated that the same growth pattern prevailed. The negative trade balance at midyear had worsened over the negative balance for the same period in 1983. An upward trend in import costs partly reflected the impact of Mexican inflation, which made that country's goods more ex-pensive and led to increased imports from North America and Europe. On the other hand, by midyear, the reexport trade with Mexico indicated an upward climb from the 1988 low of $12.7 million.

Jan 1, 1986

By J. E. Pahlman

The Bureau of Mines conducted re-search to determine the resistance of basic refractories to corrosion by ash slags that would result from the burning of coal and lignite in metallurgical operations. Basic refractories are of economic interest because they are from one-third to one-half as expensive as 90-to 99-pct-alumina refractories. Static tests were performed at 1,300° C and dynamic tests at 1,400° to 1,650° C to investigate the stability of refractory specimens in a slag environment. In alkali-containing lignite ash slags, in order of decreasing resistance, magnesite, magnesite-chrome, and chrome-magnesite refractories all had corrosion resistances equal to or better than 90-to 99-pct-alumina refractories. These basic refractories formed slag penetration layers in dynamic tests, which helped protect them from further attack. Chemically bonded basic refractories in general did not have as good a resistance to slag attack as did burned refractories of the same composition. In very acidic coal ash slag, a chrome-magnesite refractory containing 30 pct MgO plus a slag inhibitor and direct-bonded magnesite-chrome refractories with 60 pct MgO had good resistance to attack. Chrome-magnesite refractories (30 to 40 pct MgO) were moderately to severely attacked, and refractories with greater than 70 pct MgO were severely attacked by this same slag.

Jan 1, 1982

By Eugene V. Cilento, R. Clark Lantz, Kevin A. DiGregorio

"A microscope-based spectrophotometer has been developed to measure superoxide release from single pulmonary alveolar macrophages (PAM) or other phagocytes in culture. Results indicate that PAM respond to stimulation by phorbol myristate acetate (PMA). It appears that some PAM do not release 02 upon stimulation by PMA; however, those that do release 0, show differences in: (I) the total amount of 0, released, (2) the rate of release of 02 and (3) the time delay for release of 02. The significance of measuring 02 release from single cells is two-fold. It allows the simultaneous study of 02 release and electrical potential changes across the membrane of PAM and it allows the study of differences in 02 release among cells. Thus, the function of Normal PAM and the dysfunction of PAM exposed to coal dusts can be more closely studied on single cells.Pulmonary alveolar macrophages (PAM), free cells found in the lungs, protect the lungs by removing inhaled foreign debris and bacteria. The macrophages do this by engulfing and then internalizing the foreign matter (phagocytosis). Stimulation of PAM causes the release of super-oxide radical (02) which has been shown to be the primary metabolite involved in the killing of bacteria by phagocytes (3,8,12). The super-oxide radical is highly reactive and is spontaneously or enzymatically converted to other antibacterial oxidants, including hydrogen peroxide (H202), singlette oxygen ( 02), hydroxyl radical toil'), and hypochlorous acid (HOCl) (2, 3,8,11,12).Exposure of PAM to dusts may lead to dysfunction of this cell-type and to a greater risk of lung damage or infection upon subsequent exposure to toxic dusts. To date, much of the research with this cell-type has used cytotoxicity (cell death) as a measure of dysfunction. Although this is an important end point, PAM dysfunction may occur at doses below those which lead to cell death. In addition, dysfunction has been measured using large numbers of cells. In order to obtain a clear understanding of the mechanisms involved in dysfunction, measurements should be made on single cells. As mentioned earlier, one of the major roles of this cell type is its anti-bacterial actions. Therefore, asessment of release of superoxide radical in single cells is important in determining the functional behavior of PAM before and after exposure to dusts. Since measurements of 02 production have not been made on single cells the purpose of this study is to develop the methodology needed to study release of 02 from single cells.Recent studies have suggested that a relationship exists between the release of 02 and changes in the electrical properties of phagocytes. The change in membrane potential is thought to be the initial step in superoxide production (6,9). Stimulants which cause 02 release also cause changes in the transmembrane potential of phagocytes (9) and in the permeability of the cell membrane to ions (6). For example, stimulants which cause the release of 0, from neutrophils have also been shown to increase the membrane transport of Na+ , K+ and Ca+2 and stimulation of macrophages leads to increases in Na and perhaps Ca permeability with a subsequent change in membrane potential. In some cases, phagocytic activity has been shown to depend upon the extracellular concentrations of these ions (6). Holian and Daniele (7) have shown evidence that the redistribution ofcellular Ca in alveolar macrophages is an initial step leading to 0, release. In order to provide direct evidence that 02- production is related to electrical changes across the plasma membrane of phagocytes, these two phenomena must be analyzed simultaneously on single cells. Ultimately, measurements of 0, release using the methodology developed in this study will be combined with electrophysiological tech¬niques to study both superoxide release and membrane potential changes simultaneiously on single PAM, and to examine the effects of coal and mineral dusts on their physiological fu"

Jan 1, 1988

By M. S. Oudenhoven

This Bureau of Mines investigation was conducted to obtain an experimental solution of stress changes in the vicinity of a circular opening in an infinite plate. Plates were stressed biaxially in compression and subjected, by four different-length shoes, to a uniform pressure at opposing points on the opening periphery. The principal stresses along the vertical and horizontal axes, which result from peripheral pressure, were obtained from the photoelastic analysis of four frozen-stress epoxy models. These principal stresses were then super-imposed on the mathematically determined principal stresses (along the same axes) obtained from a theoretical biaxial stress field in which the magnitude of the lateral pressure was one-third that of the vertical pressure. The results indicate that an increase in shoe length increases the radial compressive stress and the tangential tensile stress (except tangential compression at r/a = 1, which exists for all shoe lengths). Also, a partial control of the stresses within one-half radius of the opening surface is accomplished by a change in the magnitude and placement of peripheral pressure.

Jan 1, 1966

By D. C. Crowell

This publication presents the results of a laboratory investigation of displacement of gas by injection or imbibition of water into sandstone models under essentially isobaric conditions. A brief discussion of scaling requirements is included. The influence on residual gas saturation of independently varying the parameters of dimensional ratios of the porous media, rates and methods of flooding, surface tension, initial water saturation, and permeability is shown. Of these variables, increased initial water saturation and decreased surface tension reduced residual gas saturation significantly, whereas variations in flooding rate and dimensional ratios had no apparent effect. No correlation was evident between absolute permeability and residual gas saturation.

Jan 1, 1966

By P. C. Good

Tungsten metal in fused form and of high purity was prepared by reducing tungstic oxide with redistilled calcium metal in a heavy-walled sealed reactor. Alloys of tungsten with vanadium, molybdenum) chromium, columbium, and tantalum were prepared by coreduction of mixed metal oxides in the same manner. This work was undertaken by the Bureau of Mines to investigate new approaches for preparing tungsten and its alloys in high-purity form. The standard method of producing tungsten metal has been the reduction of tungstic oxides by hydrogen. The resulting metal powder is compacted, sintered, and fabricated by powder metallurgy methods. Long experience in this field has resulted in the development of a technology that (by careful control of the variables such as metal composition, particle size, and sinterng technique) is well adapted to producing wire and the small shapes usually prepared from tungsten metal.

Jan 1, 1961

By A. F. Colombo, D. W. Frommer

Bench- scale tests were made to determine the applicability of flotation as a means of upgrading finished and semifinished magnetic concentrates prepared from reductively roasted iron ores . Both anionic and cationic flotation methods were used to remove siliceous gangue from the magnetic concentrates and produce upgraded products . Seven magnetic concentrates , containing from 6.7 to 13.7 percent SiO2 , were improved by the flotation treatment , yielding final concentrates containing less than 6.0 percent Si02 . Cationic flotation methods were studied on four of the seven samples ; of this group only one sample yielded better results by cationic flotation than by the anionic method .

Jan 1, 1964

By Robert A. Jankowski

The U.S. Bureau of Mines, in cooperation with the Mine Safety and Health Administration (MSHA) and the mining industry, has identified and demonstrated the effectiveness of several improved face ventilation techniques for longwall mining systems. These include the following: identifying improved techniques for measuring face ventilation parameters on longwall sections, installing curtains at the intake end of the longwall face to maximize usage of the primary airflow, identifying optimum face airflow rates for maximizing dilution effects, and coursing the primary face intake from tailgate to headgate to minimize outby airflow contamination. Application of these techniques throughout the mining industry should reduce the health hazard associated with excessive exposure to respirable coal mine dust.

Jan 1, 1993

By Steven M. Shope

The Bureau of Mines electromagnetic trapped miner location and communications system requires a thorough understanding of through-the-earth electromagnetic wave propagation. An earth model incorporating a magnetic dipole buried in a three-layered earth has been developed. The dipole source is located in the second subsurface layer. By application of proper limiting values, the three-layered model is reduced to two different two-layered models and eventually to the homogeneous half-space model. The solutions are in the form of infinite integrals. A numerical analysis was carried out and a computer program written to evaluate the surface magnetic fields. Numerical values for the magnet- ic field at the point above the source are presented in a variety of models.

Jan 1, 1982

By William P. Diamond

This report presents results of a cooperative research project between the U.S. Bureau of Mines and BethEnergy Mines, Inc. Four coreholes (two before mining and two after mining) were drilled at a longwall mine operating in the Lower Kittanning Coalbed to obtain coal and rock samples from over-lying strata to determine their gas content at various times in the mining cycle. The results of those tests indicate that 91 pct of the gas removed from the overlying strata came from coalbeds. Material balance calculations were made to compare the volume of gas produced both from gob gas vent holes drilled on the panel and gas removed by the mine's ventilation system with the volume of gas removed from strata directly overlying the panel to a height of 275 ft. This analysis indicates that only 40 pct of the total gas produced from the panel actually came from the strata directly overlying the panel. The remaining volume of gas production probably migrated to the longwall gob from overlying, and perhaps underlying, strata immediately adjacent to the panel and perhaps from greater distances downdip because of the establishment of a long-term pressure gradient in the study area.

Jan 1, 2010

By R. P. Vinson

The Bureau of Mines evaluated two real-time light-scattering dust monitors by measuring their response to Pittsburgh Seam coal dust and Arizona road dust (ARD). Both monitors, the model PDS-l, a personal dust sensor, and the model PCD-l, a digital dust indicator, are made in Japan by Sibata Scientific Ltd. Tests were conducted inside a laboratory aerosol chamber designed to maintain a uniform spatial distribution of the test dust. PDS-l and PCD-l measurements of concentrations for each test dust were averaged over 4-h test periods and compared with simultaneous gravimetric measurements. Both dust monitors responded linearly with mass concentration with both coal dust and ARD. However, the linear response of the PDS-l differed from that of the PCD-l for both dusts.

Jan 1, 1987

Develop a user-friendly computer program that permits those interested in mine health and safety to access and analyze on a personal computer (PC) employment, production, and accident data for U.S. coal and metal-nonmetal mines. This software is being designed with a major focus on flexibility and case of use. The Mine Accident Decision Support System (MADSS) will be available for distribution in mid-1994. Currently, the U.S. Bureau of Mines (USBM) is seeking volunteers willing to pilot test a preliminary version of the software and to provide suggestions for its improvement. Background Since 1975, the Mine Safety and Health Administration (MSHA) has compiled large data bases of information about U.S. mines and the reportable accidents, injuries, and illnesses that have occurred in those mines. Employment and production data arc collected on a quarterly basis from each mine and accident information is collected on an incident -by-incident basis. The USBM has compiled estimated costs for each of these accidents using computer models. All of this information is potentially useful to mine health and safety researchers. However, it has been underutilized because it is stored in large mainframe data bases that arc inaccessible to many users and/or are cumbersome and difficult to use.

Jan 1, 1993

By A. C. Fieldner

It is estimated that 6,202,235,000 gallons .of- gasoline was produced during the year 1922. The crude light oil- output Burin- the same year is estimated at 111,000,000 gallons, or 1.8 per cent of the gasoline production. In fact, if all the coal mined were coked in by-product ovens, and the light oil recovered therefrom, this product would amount to only 15 to 20 per cent of the quantity of the petroleum gasoline now produced annually. It is obvious therefore, from these figures that the light oils by present coking processes can not assume great importance as a gasoline substitute in a national sense. However, the use of light oil as a motor fuel is of real importance in districts adjacent to by-product coking operations from which a reasonable proportion of the local motor fuel supply may be derived. The certainty of diminution of petroleum resources in the relatively near future demands the utmost utilization of gasoline substitutes from the distillation of coal as well as other sources. Motor benzol is a by-product from the destructive distillation of coal. From 11/2 to 3 gallons of refined motor benzol is obtained per ton of coal carbonized. The light oil vapors are extracted from the by-product coke-oven gas by passing it upward through a series of towers in which these vapors are absorbed in a descending current of "wash" oil (petroleum distillate). The light, oil is recovered from this wash oil by distillation with live steam, the resulting crude light oil consisting of a mixture of benzol, toluol, xylol, solvent naphtha, and a small amount of other substances (unsaturated hydro-carbons, carbon disulphide, and other sulphur compounds, phenols and pyridines) is then transferred to an intermittent still and fractionated into crude motor benzol, which includes the toluol and a part of the xylol or light solvent naphtha. The crude, motor benzol is yellow in color, contains sulphur compounds which corrode copper and brass, and also contains unsaturated bodies which oxidize and polymerize on standing, producing sediment and forming gummy deposits highly objectionable when the benzol is used in motors. These objectionable

Jan 1, 1923

By R. D. Groves

Laboratory research has demonstrated that high - grade copper powders can be produced under controlled conditions from cement copper products . The technique should enable small producers to prepare a directly marketable product by means other than smelting and electrolytic purification . A continuous drum- type precipitator was the preferred unit for producing fine - sized particles of cement copper that were further processed by chemical digestion in a copper sulfate solution , by reduction and sintering in a hydrogen atmosphere , and by grinding to a powder . The effects of variables related to all stages of the process were investigated . Treatment of leach solutions from three different sources resulted in copper powders containing 99.2 to 99.8 pct Cu , apparent densities of 1.97 to 2.25 grams per cu cm , good powder flow rates , and a size distribution of 54.9 to 60.1 pct minus 325 - mesh material .

Jan 1, 1964

By Thomas Varley

Data on the consumption of reagents used in .flotation during the year 1925, in metallurgical plants in the United States, are presented in this paper. Previous reports have covered the same subject for the years 1916, 1919, 1923 and 1924. The data contained herein show departures most radical from even the 1924 practice. Flotation has developed rapidly and on a more scientific basis than ever before. Perhaps more fundamental and useful data have been uncovered during the past two years than in all the years the art has been practiced.

Jan 1, 1926

By V. A. Nieberlein

Problems of design involving the high-temperature characteristics of materials of construction have focused attention on tungsten, the metal with the highest melting point. To study the properties of this metal a method was needed to produce tungsten of high purity easily and consistently. The Bureau of Mines has made tungsten metal in massive form on a laboratory scale by hydrogen reduction of tungsten hexafluoride (WF6). Metal made in this manner had a purity of 99.99 percent or better, with reference to all detectable impurities, including gases. The process tolerated a wide variation in operating conditions, and the results with respect to total impurities as low as 0.01 percent were reproducible.

Jan 1, 1959