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By R. V. Ramani, R. Bhaskar

"IntroductionThe behavior of dust clouds in mine atmospheres has been a subject of longstanding interest due to both health and safety reasons. Pioneering studies in Germany and SMRE focussed on ambient dust concentration, principally aimed at determining optimum velocities for effective dilution. A summary of studies related to this area is provided by Hall,(l) Efforts to understand dust deposition from the explosion hazard point of view led to experiments in return airways (2-4) followed by experiments in longwalls.(5) Concerted efforts, either experimental or theoretical, were not made until recently to relate ambient concentration with dust deposition in mines. In 1974 Hwang et a1 (6) developed a computer model to predict dust concentration which considered deposition-concentration relationships. Also, experimental studies involving concurrent dust deposition and ambient concentration were conducted in the U.S. by Courtney et al (7 ) in operating mines. Efforts to relate theory with experimental results have been made by Owen (8) and Hwang et al (6 ) for dust deposition. There has been limited work, however, to determine the application of the theories and assumptions from aerosol sciences for modeling dust flows in mine atmospheres. (9 ) This is the objective of the work currently underway in the Generic Technology Center on Respirable Dust since· 1983 under a project titled, ""Prediction of Ambient Dust Concentration in Mine Atmospheres."" The scope of the project activities include:1. Development of a mathematical model to predict dust deposition and concentration in mine atmospheres.2. Experimental studies on dust transport and deposition in mine airways.3. Comparison of the model results with the experimental data."

Mar 1, 1989

By Foster Fraas

Electrostatic separation depends on a number of electrical and mechanical properties such as conductance, contact potential, dielectric constant, and particle shape. In routine testing it is desirable that the application of each of those properties be investigated. The conductance property is best utilized in a separator having an ionic field, whereas the contact potential requires a separator with a pure static field. Dielectric constant and particle shape also influence the response in these two fields. There is no separator on the market that can be adjusted for all these requirements. The separator described in this paper is satisfactory for this purpose and is provided with a dielectric electrode, which permits formation of high-intensity static fields.

Jan 1, 1951

By N. S. Dalal, B. Jafari, X. Shi, M. M. Suryan

"It is well known that prevalence and severity of coal worker's pneumoconiosis (CWP) differ markedly in different regions and mines despite comparable exposures. These variations in the pathogenicity of different coal mine dusts can only partially be explained by the mineral composition of the coal mine dust and the rank of coal. Laboratory studies also do not correlate with the human experience. One major difference between human exposure and laboratory studies is that the coal miner breathes dust from freshly broken coal, while the animals or cells are exposed to stale dust. In an effort to find biochemical clues for resolving this apparent paradox, we have carried experiments to detect differences in chemical reactivities of fresh versus stale coal dust from several U.S. coal mines. Electron spin resonance (ESR) was used as a technique for the direct detection of the concentration and reactivity of free radicals. ESR measurements of freshly ground coal dusts of different ranks and composition showed significant differences in the amount and reactivities of the organic free radicals produced. The half-lives and reactivity patterns of these newly formed species of free radicals seem to correlate with the expected toxicity and pathogenicity of the dust, thereby, providing new clues to the biochemical mechanisms and pathogenesis of CWP. Similar detection of free radicals in freshly crushed quartz suggest that free radicals might play a significant role in the pathogenicity of quartz in causing fibrosis and eventually silicosis.IntroductionThe pathogenesis of coal workers' pneumoconiosis (CWP) has been an important topic of concern for decades, but the mechanism of CWP is still not understood. It is well known, for example, that the prevalence and severity of CWP differ markedly in different regions and mines despite com¬parable exposure'(1,2) but these observations can only par¬tially be explained by differences in mineral composition and rank of coal (3-5) Specifically, while epidemiological studies of coal miners indicate (1,2) that the effectiveness of coal in producing CWP correlates roughly with the rank (i.e. %,carbon content) of coal, such correlation has not been established via biological studies.(4-6)"

Mar 1, 1989

By d&apos, Kathleen J. Amico

THIS SUAMMARY is shown in Minerals Yearbook volumes I and III of this series on mineral production in the United States, its island possessions, the Canal Zone, and the Commonwealth of Puerto Rico, and on the principal minerals imported into and ex- ported from the United States. The several commodity and area chapters contain further details on production. A summary table comparing world and U.S. mineral production also is included. Mineral production may be measured at any of several stages of extraction and processing. The stage of measurement used in the chapter is normally what is termed "mine output." It usually refers to minerals in the form in which they are first extracted from the ground, but customarily includes for some minerals the product of auxiliary processing operations at or near mines.

Jan 1, 1962

By Robert L. Virta

The Bureau of Mines examined a fibrous talc sample from the Gouverneur talc district in New York by transmission electron microscopy (TEM) and polarized light microscopy to determine the mineralogical relationship of the fibrous talc to the amphiboles present in the sample. Two am-phiboles, anthophyllite and tremolite, were present in the sample. Tremolite occurred as a separate mineral phase, which was blocky in habit. Only a few composite tremolite-talc grains were observed. An-thophyllite, however, was present only in the fibrous talc grains. Mi-crodiffraction study of the fibrous talc grains containing anthophyllite showed that the anthophyllite was intermixed with the talc on a fine scale and that there was a crystallographic relationship between the talc and anthophyllite lattices in the fibrous talc grains. A mechanism similar to the process that forms biopyriboles could explain the structural defects, the fibrous habit of the talc, and the structural relationship between the talc and anthophyllite in the fibrous talc grains. Because of these characteristics, phase contrast microscopy and a provisional TEM technique for monitoring asbestos exposure would not distinguish between fibrous talc and fibrous amphiboles. TEM techniques employing electron diffraction and energy-dispersive X-ray analysis are recommended to positively identify the fibrous phases for regulatory purposes.

Jan 1, 1985

By W. W. Adams

Reports received by the Bureau of Mines, Department of Commerce, from State mine inspectors, for November, 1930, showed that 219 men were killed in the coal mines of the United States during the month, an increase of 25 over the previous month and 33 over November, 1929. On the other hand the production of coal decreased, the output of 43,329,000 tons in November being 8,397,000 tons less than in October and 9,005,000 tons less than in November a year ago. The larger number of fatalities accompanied by a smaller output of coal resulted in a higher death rate4 per million tons in November than in the same month last year or in October, 1930. The November rate was 5.05, as compared with 3.55 for November, 1929 and 3.75 for October, 1930. The increase in the rate for the industry as a whole was chargeable entirely to bituminous mines,, as the anthracite mines had fewer fatalities in November than in either of the previous months to which reference has been made. Reports for bituminous mines alone 'allowed that accidents at class of mines resulted in a death rate of 5.12, based on 195 fatalities and a production of 38,122,000 tons. This rate indicated an increase of 55 per cent over the rate for October, of the same year, and 72 per cent over the rate for November, 1929. The October record was 146 fatalities and 44,150,000 tons, and that for November a year ago was 138 deaths and a production of 46,514,000 tons. Twenty-four deaths occurred at anthracite mines in November, 1970: the output of coal was 5,207,000 tons, hence the rate was 4.61 per million tons. During the corresponding month a year ago there were 48 deaths and 5,820,000 tons of coal produced, which indicated a death rate of 8.25. In October, 1930, the death rate was o.34; based on 48 deaths and 7,576,000 tons.

Jan 1, 1930

By Philip C. Tully

This Bureau of Mines report contains experimentally determined vapor-liquid equilibria data for a helium-nitrogen-methane mixture with a nominal composition of 15, 60, and 25 mole-percent, respectively. Measurements of the equilibrium phase compositions were obtained by means of a windowed cell, in conjunction with an automated chromatograph and a special analyzer for low helium concentrations. The data presented include a comprehensive table and eight graphs depicting phase compositions, vaporization ratios, and correlations with a previous study of two helium-nitrogen-methane mixtures of different compositions.

Jan 1, 1976

By C. J. Thompson

Two sulfur compounds--the 2,2,5-trimethyl- and the 2,2,5,5-tetramethyl derivatives of thiacyclopentane--were identified in Wilmington, Calif., crude oil, using microdesulfurization and gas-liquid chromtography techniques.

Jan 1, 1963

The principal activities of the Bureau of Mines Explosives Research Center from July 1, 1963 to June 30, 1964 are described briefly in part 1. Part 2 gives short abstracts of publications that appeared during fiscal year 1964; in general; the research reported in these publications antedates the report period. Part 3 describes a short-term investigation into safety problems associated with shipping of molten sulfur; this investigation is not at present destined for publication elsewhere.

Jan 1, 1965

By Ralph B. Adair

The Bureau of Mines conducted laboratory and continuous pilot plant flotation tests to determine the feasibility of recovering commercial-grade mica from an Alabama graphitic-mica schist. Preconcentration of the ground ore on a Humphrey's spiral was employed to reject the heavy minerals and part of the quartz in a product virtually free of mica. The acid-cationic mica flotation process recovered over 89 percent of the mica in a product containing 98.7 percent mica. Grinding of the mica concentrate in a fluid energy mill produced a product with a bulk density of 12 lb per cubic foot.

Jan 1, 1969

By F. D. Everett

The exploration work on a seleniferous tuff deposit near Lysite, Wyo., was confined chiefly to an area of approximately 1 square mile selected on the basis of prior examination and sampling work by the Bureau of Mines. This area was superficially explored by digging and sampling over 2,000 feet of trenches and 15 test pits. The surface sampling indicated that the deposit might contain a multimillion-ton reserve of easy-to-mine volcanic tuff assaying more than 0.01 percent Se. Later, 11 holes, ranging in depth from 57 to 135 feet and totaling 929.4 feet, were drilled under contract using a dry rotary drill. Samples for assay were cut at 5-foot intervals or at noticeable physical changes in the formation being drilled. Of the 206 samples assayed from the drilling, only 8 contained more than 0.005 percent selenium, and 2 of these assayed as high as 0.012 percent Se. Chemical analyses of samples obtained from six holes drilled by the Nugget Coal & Timber Co. to the south of the area explored by the Bureau of Mines showed that no selenium-bearing formations were encountered in that work. Two of 72 samples taken from 42 validation pits dug by claim holders contained more than 0.005 percent selenium. The exploratory work established that the selenium mineralization is erratically distributed in small irregular bodies and is not confined to any one tuff bed. Because of the lack of correlation between the infrequent showing of low-grade tuff, neither the extent nor grade of the reserves could be calculated.

Jan 1, 1957

By Steven J. Page, John A. Organiscak

Prolonged exposure to airborne respirable coal mine dust is responsible for coal workers' pneumoconi¬osis (CWP): Furthermore, miners who show evidence of higher radiographic categories of simple CWP are at increased risk of developing progressive massive fibro¬sis (PMF). As of 1990, there were nearly 130,000 coal miners in the United States. "' This excludes mines that produce less than 10,000 tons annually and the anthracite coal mines. Estimates indicate that at age 58, an average of 7/1000 U.S. workers and 89/1000 U.K workers will have developed PMF(2-1) Health research studies have iden¬tified that the risk of developing and the severity of CWP arc directly related to (1) the amount of respirable dust exposure and (2) the coal rank.,'- The rank of coal is its stage of formation in the series peat, lignite, sub-bituminous, bituminous, and anthra¬cite (in order of increasing rank). The rank of coal can also be represented by the com¬mercially important characteristics specified by its proximate analysis: fixed carbon, vol¬atile matter, mineral matter, and moisture content.

By T. N. McVay

The various applications of beryllium and its compounds in atomic - energy technology and a growing recognition of possible increased utilization of the metal in the aircraft and space - missile fields have resulted in increased interest in domestic and world reserves of beryllium . Unfortunately, little dependable data on beryllium resources and reserves are available , as past consumption of the element has been small and only limited prospecting and exploration work has been done . The scarcity of resource information is attributed partly to the difficulty of recognizing beryllium minerals in the field . These minerals frequently do not have distinctive characteristics of specific gravity, color , or other physical properties , that enable ready identification by the average prospector . This is particularly true of fine - grained minerals . As a result , a simple field test for identifying beryllium- bearing rock is needed . Recognizing this , technologists of the Federal Bureau of Mines investigated several of the proposed qualitative chemical tests for beryllium . This report describes various modifications of one of these methods to make it more suitable for use in the field . In the modified method , duplicate samples are fluxed -- one with potassium bifluoride and one with potassium bisulfate -- followed by dissolution of salts in water , conversion of the solution to an alkaline condition, addition of morin , and examination of the solution for fluorescence under short -wave ultraviolet light . This method provides a fast , dependable field test for beryllium minerals containing as little as 0.2 percent beryl or its equivalent . The test involves no radiation hazards , and it can be performed by persons having no technical training ; therefore , it should be useful to prospectors in discovering beryllium mineralization .

Jul 1, 1960

By N. L. Kozlinsky, B. W. Gandrud

"The Marvel mines 1 and 3 of the Roden Coal Co. are located in the Cahaba field in Bibb County, Ala., nearly southwest from Birmingham, an airline distance of roughly 30 miles. The coal of the Clark seam at this point has some coking properties, but at present it is sold exclusively as a domestic and steaming coal.This paper, which is the second of a series on the washability of Alabama coals, like its predecessor dealing with the Mary Lee seam,5 contains screen-sizing and float-and-sink tests of a representative sample of the raw slack, and slotted-screen tests showing the proportions of flaky particles in certain selected sizes; inasmuch as this coal is not used for coke manufacture, no crushing tests have been made. These data have been obtained in connection with an exhaustive study of coal preparation in Alabama, now being conducted by the United States Bureau of Mines and the University of Alabama with the cooperation of the different coal operators. As the work progresses, other papers will follow containing further data on Alabama coals and giving results obtained in preparing these coals by various methods.The only published investigative work on the Clark seam is that of Forbes,6 who gives a number of sections of this seam in Marvel No. 3 mine with proximate and ultimate analyses of face samples taken in the mine and also some analyses of delivered coal.The available information on this coal indicated that the preparation problem was one of ash reduction. In order to substantiate this information a complete analysis of the 3/4 by 3/16 inch size, and sulphur determinations and ash-fusibility tests of the float-and-sink fractions have been made; these results are given in Tables 1 and 2. As these results also indicate that the preparation problem is one of ash reduction, the tests and discussion have been devoted to that subject."

Jun 1, 1930

By Jerry W. Ramsey

The Bureau of Mines examined a low-, a medium-, and a high-volatile Pennsylvania anthracite by densimetric methods using four mesh si.s of each anthracite. Using high-pressure mercury the macropore volumes and distributions of these pore volumes determined, densities in mercury were calculated, and specific pore vo1.r. ware obtained from these mercury densities in conjunction with helium densities. The helium densities were also used with the ultimate analyses of these anthracites in calculating structural parameters by statistical densimetric methods. The effect of 106 or 108 rads of gamma irradiation in the presence of air and in vacuum upon the properties studied with two mesh sizes of each anthracite. Results of the statistical densimetric method seem to show some breakdown of condensed ring structural units at the lower irradiation level, with subsequent polymerization at the longer period of gamma irradiation. The structural parameters obtained also indicated that in going from high- to low-volatile anthracite, either the number of condensed rings per structural unit increased, or the degree of polymerization increased.

Jan 1, 1965

By M. R. Geer

Three coals from the Wilkes on - Carbonado district of Pierce County , Washington , were subjected to washability analyses to estimate the amount and quality of washed coal obtainable . Because the coals were unusually difficult to clean , the washability examinations were supplemented by table tests , tests in dense - medium cleaning units , and flotation tests . None of the coals could be reduced to the desired 10 percent ash by tabling and the response to flotation by two of them was poor . Dense -medium treatment provided coal of the desired quality , but with the most difficult coal the recovery efficiency was lower than usual .

Jan 1, 1964

By A. N. Fried

One of the important problems confronting oil producers in appraising the possibilities of secondary recovery in many California fields is the effect of viscosity on oil recovery by water flooding. In January 1954 there were 554 fields and/or pools, in the State, that produced 1 million barrels daily, and 138 of these pools produced approximately 267 thousand barrels daily of heavy crude oil having gravities below 200 API. Many of these fields are nearing the end of their primary economic life and still have high residual-oil saturations, a favorable factor in water flooding. The crux of the problem is whether or not enough oil can be recovered from these fields by water flooding to make the operation economically successful. Some experiments on the relationship between viscosity and oil recovery have been made by other investigators, but in most instances the viscosity of the oils used in the experiments was lower than the viscosity of the oils found in many of the heavy-oil fields in California. A study was undertaken, therefore, to determine the relationship between oil viscosity and recovery over a wider range of viscosities and to compare the experimental results with those predicted by theoretical calculations.

Jan 1, 1955

By Charles L. Parsons, R. B. Moore, S. C. Lind, O. C. SCHAEFER

Early in 1912, from information received by the Bureau of Mines, it became evident that quantities of valuable radium-bearing ore from Colorado were being exported for manufacture in foreign coun- trics and that at least part of the manufactured product was being returned to this country and sold at a price entirely incommensurate with that received by the miner and the prospector. Consequently, in line with its efforts to increase efficiency in the mining and treat- ment of mineral resources, the Bureau of Mines undertook an inves- tigation of conditions. Results of this preliminary investigation were published, in the summer of 1913, as Bulletin 70, which gave an out- line of the radium deposits of the West, the conditions of mining, the wastes involved, and the status of the production of radium from its ores. At about this time newspapers and medical journals were publish- ing statements regarding the value of radium in cancer therapy. These reports, although many of them were exaggerated, brought out clearly the remarkable virtue of the gamma rays for the treat- ment of cancer and other malignant growths. In view of the fact that the largest known supplies of radium ore in the world are in the States of Colorado and Utah and on the public lands of the United States, it was deemed highly important for the Bureau of Mines to study the production of radium in detail. Such study, it was hoped, would enable the prospector and miner to obtain a fairer price for the ores and would furnish information necessary in case Congress appropriated funds to develop methods for extracting radium from ore on the public lands under Government supervision, to be supplied at cost to the hospitals of the Army, Navy, and Public Health Service.

Jan 1, 1915

By Victor Kalcevic

A gas-flow retort for thermal processing of oil shale to recover shale oil was developed by the Bureau of Mines at its Oil-Shale Demonstration Plant, Rifle, Colo., from 1948 to 1952. The retort is a crossflow gas-to-broken-solids heat exchanger. The heating medium is the gas produced in the shale retorting process. The gas is heated in specially designed stoves outside the retort and recycled to the retort. Oil shale from the Mahogany ledge section of the Green River formation in northwestern Colorado was the material processed. Indicated maximum oil recoveries for 20-to 25-gallon-per-ton shale in a l2-inch-thick shale bed and a 20-inch bed are 96 and 91 weight-percent of Fischer assay, respectively. Heat requirements for maximum recovery are 600 to 750 B.t.u. per pound of shale. Properties of the recovered shale oil are affected slightly by shale-bed thickness and extent of retorting. Oil recovery from oil shales assaying over 30 gallons per ton is lower than that from leaner shales.

Jan 1, 1959

By E. C. Perkins

The purpose of the research described in this report was to develop techniques for using ilmenite from domestic deposits for the production of titanium tetrachloride. The research was done by the Federal Bureau of Mines in cooperation with the General Services Administration under contract DMP-116, Utilization of Domestic Ilmenite. Bench-scale continuous chlorination of an Idaho ilmenite containing 27.9 percent titanium and 35.6 percent iron yielded a crude titanium tetrachloride suitable for purification and for the production of titanium metal and pigment. A summary of the results of 380 hours of operation showed that 82.4 percent of the titanium was chlorinated, with 92.5 percent utilization of chlorine. The construction- of a. quartz tube chlorinator 4-inches in diameter and 24 inches long is described with the necessary details of operation.

Jan 1, 1961