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By H. R. Shell

Of three known compounds in the ternary system K20 - PbO - SiO2, one having the composition K2Pb4Si8021 crystallizes into a structure with asbestiform properties. This compound, whose silicon-oxygen ratio is between that of the layer silicates (for example, mica) and the double-chain amphiboles, crystallizes in the tetragonal system. It malts, apparently congruently, at 779° C. The fiberized product prepared from crystals is fluffy and closely resembles natural asbestos in appearance, but is more brittle and has less strength. However, potassium-lead silicate may be separated into fibers with a uniform diameter of 200-300 A.U., and the fibers show with the electron microscope the s criteria that have been interpreted as indicating a hollow tube structure in chrysotile asbestos. Since very few inorganic crystalline compounds have such a structure, the material has unusual scientific interest. Microcrystalline potassium-lead silicate was rapidly and completely formed when powdered glass of the same composition was heated to 650° - 700° C, but macrocrystals grew only slowly from the viscous massive glass. Maximum growth rate was 0.12mm. per hour at 700° C.

Jan 1, 1957

By Donald F. Reed

The bauxite deposits of Tippah and Benton Counties in northeastern Mississippi were developed by drilling as a part of the investigation by the Bureau of Mines of the domestic sources of supply of aluminum. The primary purpose of investigations of this nature was to provide essential information to the war agencies of the United States Government and to assist owners and operators of mining properties in the production of minerals vital to the prosecution of the war. These reports are based upon the field work of the Bureau of Mines and upon data made available to the Department from other

Jan 1, 1948

By V. Vallyathan, Xianglin Shi, N. S. Dalai

While Cr(VI) is a known carcinogen, the underlying biochemical mechanism is still not fully understood (1). In a pioneering study Jennette (2) utilized electron spin resonance (ESR) spectroscopy to demonstrate that a long-lived Cr(V) species is generated during the reduction of Cr(VI) by microsomes in the presence of NADPH. Later Wetterhahn and co-workers (3, 4) showed that incubation of chromate with isolated rat liver mitochondria causes the reduction of Cr(VI), as well as the formation of a Cr(V) species. Analogous Cr(V) species have also been detected in the reduction of Cr(VI) by other cellular systems such as Hanserulla polymorphared (5) and blood cells (6, 7). All these as well as other studies (8-12) have suggested that this Cr(V) species plays a significant role in the mechanism of Cr(VI) toxicity. Thus far, however, the chemical structure of this dominant Cr(V) species formed in cellular systems has not been identified, and this observation provided an impetus for the present investigation. Another reason for undertaking this study was that some recent reports (10-16) suggest that hydroxyl ('OH) radicals may also play an important role in the mechanism of Cr(VI) toxicity. In particular, it has been shown that OH radicals are formed in reactions between Cr(V) species and H2O2 (13-16), and that the radical yield depends on the chemical structure of the Cr(V) species (15). For example, while Cr(V)-diol complexes efficiently generate OH radicals, another Cr(V) species, the tetraperoxochromate (CrO3/8) ion, does not (15). Thus in the present study, we focused our attention on the following: (a) structural identification of the Cr(V) species generated in the reduction of Cr(VI) by subcellular as well as cellular systems, using microsomes, mitochondria, and Escherichia coli; (b) possible detection of OH radical in the same systems since there is no earlier report of chromium-mediated generation of 'OH radicals in a cellular system; (c) possible involvement of molecular oxygen in chromium-related OH radical generation since a recent report (17) indicated that Cr(VI) mutagenesis is strongly oxygen dependent; and (d) elucidation of the mechanism of OH radical formation in these systems.

Mar 1, 1992

By David Schlain

"INTRODUCTION Electrolytic manganese is produced by electrolysis of a solution of manganese sulfate and ammonium sulfate in a diaphragm-type cell, metallic manganoese being deposited on the cathodes and sulfuric acid produced at the anodes. The spent electrolyte is used to leach fresh ore that has previously been subjected to a reducing roast; the resulting leach liquor is purified and returned to the cell.The leach liquor produced at the Bureau of Mines pilot plant 3/ at Boulder City, Nev., contains 135 to 140 grams of ammonium sulfate and 32 to 36 grams of manganese (as sulfate) per liter, and has a pH of about 2.5. After neutralization to a pH of 6.4 to 6.6 with ammonia and thickening, 0.10 to 0.15 gram of hydrogen sulfide per liter is added to the liquor to precipitate the heavy metals, and after 15 to 30 minutes the precipitate is filtered off. Residual sulfides and colloidal material are removed by ferric hydroxide formed by adding a small amount of ferrous sulfate to the solution at a pH of 6.5 to 7.0 and passing air through it. The solution is then filtered and clarified as a precoat filter. Finally, 0.1 gram of sulfur dioxide per liter is added, and the solution is electrolyzed in an anode-in-diaphragm cell. The spent electrolyte coming from the cell contains approximately 10 grams manganese, 135 grams ammonium sulfate, and 45 grams sulfuric acid per liter."

Oct 1, 1946

By Efrem R. Reeves

Noise-induced hearing loss (NIHL) is the most common occupational illness in the United States, with 30 million workers exposed to excessive noise levels [NIOSH 1996] every day. Of particular concern is the mining industry; which has the highest prevalence of hazardous noise exposure of any major industry sector [Tak et al. 2009] and is second only to the railroad industry in prevalence of work-ers reporting hearing difficulty [Tak and Calvert 2008]. This document is for operators, safety personnel, and mechanics in the mining industry who are not specialists in noise control engineering or acoustics. Evaluations of successful and unsuccessful attempts at controlling noise on several large, underground metal mining machines are detailed to illustrate the basic principles of noise control. Once personnel understand the guidelines and principles of noise control, they will be able to ¦evaluate the extent of a noise problem; ¦determine the best approach to the problem; and ¦apply the most appropriate solution. Because of the insidious nature of NIHL, it can go unnoticed until a considerable loss of hearing has occurred. In some cases, diagnosis is delayed because an exposed individual claims to have become accustomed to the noise. In reality, that person may have already suffered irreversible hearing loss. Humans can hear sounds in the frequency range from about 20 to 20,000 Hertz (Hz). Within this range, NIHL usually begins in the frequency region around 4,000?6,000 Hz, the upper levels of the speech region. The first noticeable symp-toms include difficulty understanding higher pitched voices, such as the voices of females and children, and difficulty understanding certain consonant sounds, which are primarily high frequency in nature. The extent of NIHL varies depending on the level and duration of noise exposure and on an individual?s susceptibility; despite having similar noise exposure, individuals can experience differing degrees of hearing loss, or none at all. NIHL is almost always preventable. To reduce or eliminate the possibility of NIHL, an individual?s noise environment must be analyzed and appropriate action taken to reduce noise exposure.

Dec 1, 2009

By J. S. Dunning

The Bureau of Mines investigated a series of Fe-Al-Mo alloys strengthened by ZrC (zirconium carbide) precipitates as chromium-free substitutes for stainless steels. Melting and fabrication methods were devised, and the effects of minor additions of columbium (niobium) and cerium on the mechanical properties and oxidation resistance were determined. Zirconium carbides could not be con-trolled reliably to produce fine precipitate dispersions. A more reliable carbide strengthening mechanism is required if the high-temperature strengths of types 304 and 316 stainless steels are to be duplicated. Workability and oxidation resistance of the alloy series were excellent.

Jan 1, 1982

By W. Miola, R. V. Ramaoi

"The MSHA prescribed method for the determination of quartz in airborne respirable-dust samples from underground coal mines is the P-7 method, a combination of /ow-temperature, radio-frequency ashing (LTA) and infra7 red analysis (IR). There is no prescribed procedure for quartz analysis in bulk samples of coal and host rock. Dispersive infrared (IR), Fourier-transform infrared (FTIR) and X-ray diffraction (XRD) methods are most commonly used for the analysis of quartz in powders. Several aspects of the experimental procedures, such as the preparation of the analysis sample from bulk samples, ashing techniques, scanning procedures, peak measurement location, calibration techniques, sample amounts, size consist and data interpretation, affect the results from each of the methods differently. Significant differences in analytical results obtained from X-ray diffraction (XRD) and infrared spectroscopy (IR) on the same samples are reported. All studies point to the need for reliable quartz analysis methods.In a recent research program, a procedure for preparing bulk-coal and host-rock samples for quantitative quartz analysis was developed. Further, the results from X-ray diffractometry and infrared spectroscopy for quartz content on identical samples were compared. Calibrations with pure and mixed standards were used to assess the influence of particle-size distribution, matrix and calibration on the analytical results. In this paper, several issues concerning the measurement of quartz in the samples of coal, host-rock and airborne respirable dust from mines are outlined and quantified. IntroductionThe literature on coal-mine airborne-dust control has identified a need for a better understanding of the sources, mechanisms and amounts of quartz in mine airborne respirable dust (Althouse, 1984; Jankowski, Nesbit and Kissel, 1985; Ramani 1988; Qin, 1988; Bhaskar and Xu, 1990; Bhaskar and Li, 1992; Ramani, Qin and Miola, 1991 ). To understand the quartz content in the source materials, bulk samples of coal and host rock must be analyzed. Establishing an analysis procedure for determining the quartz content in bulk-coal and host-rock samples is necessary for identifying the sources of quartz in mines; for establishing the relationships between the quartz contained in the source and in the airborne dust; and for controlling the content of quartz in the mined product and in the airborne respirable dust."

Dec 1, 1996

By Oliver C. Ralston, Dorsey A. Lyon

Volatilization in retorts has been, until recently, the only commercial process of producing spelter, hence the zinc mine operators have had to meet the terms of the zinc smelters in regard to the following requirements: (1) Minimum percentage of zinc the ore must contain; (2) the chemical combination of the zinc in the ore; (3) the proportion present of those elements that interfere with the suceessful recovery of the zinc when the ore is retorted. In consequence of these requirements, only a comparatively small proportion of the zinc ores mined can be shipped directly to the smelters.

Jan 1, 1919

By L. C. Brichta

During a study of the Badger-Peacock area from October 1950 to June 1953, the Federal Geological Survey and the Federal Bureau of Mines completed nearly 98 miles of resistivity profiling and drilled 96 test holes aggregating 17,628 feet of bore, In addition, seismic profile measurements were made along 8 traverse lines for an aggregate length of about 16,600 feet. The geophysical surveys were conducted by the Geophysics Branch of the Geological Survey; the drilling was done by the Bureau of Mines. Electrical-resistivity measurements disclosed 21 low-resistivity anomalies and 1 high-resistivity anomaly. Correlation of the resistivity data with the geological information revealed by the drilling disclosed that the low-resistivity anomalies indicated either slumped shale deposits in limestone sinks or undisturbed deposits of shale lying in erosional depressions in the limestone. The high-resistivity anomaly indicated hard, undisturbed limestone at or near the surface.

Jan 1, 1958

By R. F. Abernethy

Analytical results, including ash fusibility data, are presented by the Bureau of Mines for 10 major constituents in coal ash from 373 samples of commercial U.S. coals. Determinations of Si02, Al2O3, Fe2O3, and P2O5 were made by colorimetric methods, Na2O and K2O by flame photometry, Ti02, CaO, and MgO by a spectrochemical method, and SO3 by a gravimetric method. In bituminous coal ashes the silicon, aluminum, and iron calculated as oxides often make up about 90 percent of the ash.

Jan 1, 1969

By R. V. Lundquist

Aeration in water slurries and controlled drying of manganous hydroxide produced from dithionate leaching of Artillery Peak manganese ores from Arizona were investigated by the Bureau of Mines at its Electrometallurgical Experiment Station, Boulder City, Nev., to determine whether a simple process could be developed for converting this product into a battery-grade manganese dioxide. The properties of manganese dioxide prepared by the thermal decomposition of manganous nitrate were investigated also. Manganese dioxide suitable for use in batteries was not obtained from the dithionate leach product, but some of the factors controlling its oxidation were isolated. Aging of manganous hydroxide was of major importance in retarding its oxidation by aeration. Sodium hydroxide and sodium silicate promoted oxidation by drying. Optimum quantities were about 0.85 mol of sodium hydroxide and 0.2 mol of sodium silicate per mol of manganese, and drying temperatures of 200° C. produced yields of manganese dioxide up to 90 percent of the manganese present. Higher temperatures and concentrations of reagents carried oxidation of manganese beyond its tetravalent state.

Jan 1, 1957

By V. A. Nieberlein

The purpose of this investigation is to determine the reserves of columbium (niobium) minerals in Arkansas and to develop metallurgical methods for concentrating the minerals and extracting the metal. The columbium resources of central Arkansas were explored by drilling and trenching, and a number of samples were taken. On the basis of this exploration the known reserves of the metal were estimated to be over 78,000,000 pounds. The reserves could possibly be extended by additional exploration to 150,000,000 pounds.

Jan 1, 1954

By A. R. T. Denues

This investigation was made under a cooperative agreement between the United States Department of the Interior, Bureau of Mines, and the Pittsburgh Testing Laboratory. Funds were supplied by the Chile Exploration Co., whose executive offices are in New York City. The support, cooperation, and services of these agencies made the work possible and are acknowledged gratefully. The writer wishes to express his particular indebtedness to the staff of the Explosives Division of the Bureau of Mines for services and assistance, particularly Dr. Wilbert J. Huff, consulting explosives chemist, J. C. Holtz, J. E. Tiffany, and A. B. Coates; to F. O. Gardner, treasurer of the Pittsburgh Testing Laboratory; to G. B. Holderer, consulting engineer in connection with liquid-oxygen explosives for the Chile Exploration Co.; to the Enos Coal Mining Co. of Oakland City, Ind., particularly to G. H. Utterback of the staff of the mine for providing facilities that made field tests possible; and to full-time assistants J. W. Rothhaar and J. G. P. Weinheimer and to W. S. Hiller, part-time assistant, who were employed under the cooperative agreement.

Jan 1, 1940

By A. C. Richardson

During the past two and a half years the U. S. Bureau of Mines and the University of Alabama, with the cooperation of the different coal operators, have been making an extensive study of coal preparation in the State of Alabama. Considerable time has been devoted to the study of the washing characteristics of the Mary Lee bed and the various methods used in preparing from it a low-ash coal suitable for the manufacture of metallurgical coke. One of the phases of this problem is the utilization of middlings products from the washing plants. This paper gives the results of treating jig middlings on a coal-washing table at the Bureau of Mines laboratory at Tuscaloosa, Ala. The sample used was secured from the Sayreton washery Of the Republic Steel Corporation, Sayreton, Ala.

Jan 1, 1931

By Mary S. Esfandiary

U.S. scientists attempting to maintain continuous surveillance of scientific information are confronted with two acute problems: The steady, even spectacular; increase in the volume of such information and the fact that much of it is published in unfamiliar foreign languages, According to the National Science Foundation, almost one-third of the world's scientific literature is published in languages that are read by less than 5 percent of U.S. scientists. Most scientists in the United States must rely on abstract journals and translations to obtain information on developments in research and investigations conducted in the non-English-speaking countries. However, there are problems involved in procuring suitable abstracts and translations and in obtaining such information as cheaply and rapidly as possible.

Jan 1, 1961

By W. W. Adams

"The results of the fourth annual safety contest, 'mown as the National Safety Competition, contacted by the United States Bureau of Mines are herein announced. A bronze trophy, ‘Sentinels of Safety’, the gift of the Explosives Engineer magazine, has been awarded to the leading mine in each of the five groups into which the mines and quarries that participated in the contest were arranged. These five groups were: anthracite mines, bituminous coal mines, metal mines, nonmetallic-mineral mines, and carries and open-pit mines. The leading plant in each group was the mine whose employee lost the smallest number of days from accidents in proportion to the total number of man hours worked. Where two or more mines operated without a lost-time accident, the winner was adjudged to be the plant which operated the largest number of man hours during the year.The contest was based upon reports of accidents and exposure sent by the competing companies to the Bureau of Mines. Records of the five leading companies in each group were made known to a Committee of Award, consisting of the following seven members: H. Poster Bain, Secretary of the American Institute of Mining and Metallurgical Engineers; James F. Callbreath, Secretary of the American Mining Congress; W. H. Cameron, Managing Director of the National Safety Council; H. L. Gandy, Secretary of the National Coal Association; A. T. Goldbeck, Director of the Engineering Bureau of the National Crushed Stone Association; William Green, President of the American Federation of Labor; and A. J. R. Curtis, Assistant to the General Manager of the Portland Cement Association. Members of the committee voted for the winning company in each group in accordance with the rules governing the contest.. A majority vote prevailed."

May 1, 1929

By Irving Wender

This report describes Bureau of Mines experiments and reviews the work of others on the exposure of coal and coal-derived products to gamma rays and some other types of radiation. Results are presented on tests of three bituminous coals and a lignite that had been pulverized to minus 200-mesh particles and exposed to 1,000 megaroentgens of gamma irradiation from spent-fuel elements of a nuclear reactor. Of about 20 chemical and physical tests in Bureau work, only mass spectrometry of gases evolved during vacuum pyrolysis of the coals to 450° C gave results indicating differences in the irradiated and unirradiated samples. Mass-spectral distribution curves for CO and CO2 evolution showed fewer irregularities (reversals of curvature) for irradiated coals; thus, mass spectrometry appears to be the most sensitive method for determining radio-induced changes in coal. It is concluded that coal is not significantly altered by gamma irradiation owing to the resistivity of its highly condensed ring structure. High-level gamma irradiation, therefore, is unlikely to prove advantageous in coal processing and utilization. Specially treated coals, because of resistivity of coal to radiation damage, may be useful as an absorbent in processing radioactive wastes.

Jan 1, 1968

By J. V. Batty

In the course of the investigation of manganese mineral occurrences in the United States, Bureau of Mines examining engineers collected several lots of ore from the Black Rock, Kramer, and. Morgan-Cromar properties, Tooele and Juab Counties, Utah. Extensive laboratory tests were made to determine the amenability of the ores to standard ore-dressing methods of concentration. The Black Rock claims 1 and 2 are 42 miles northwest of Jericho, Tooele County, Utah. A. J. Huber of Salt Lake City and Ross Rydalch of Tooele, Utah, are the owners. The deposit-is reported to be a definite manganese fissure vein in quartzite along which considerable shearing and cross fracturing have occurred. Laboratory work was conducted on a 2-ton sample of run-of-mine ore procured by a Bureau of Mines examining engineer and two smaller, higher-grade samples submitted by the owners as a result of later development. The Kramer deposit is described as a bed of manganese oxides in quartz. The property is being worked by L. E. Kramer, Tooele, Utah, and is 41 miles northwest of Jericho) Tooele County, Utah, approximately 1 mile north of the Tooele-Juab County line. A 1-ton run-of-mine sample was submitted for testing by the examining engineer.

Jan 1, 1952

By J. E. Matta

The methane gas emitted from coal samples collected from the conveyor belts dumping into silos was measured by the Bureau of Mines. Approximately 50 pct of the total gas desorbed into a sealed can within 1 week was released during the first 24 hours. No simple correlation between the gassiness of the coal stored and the methane concentration in the silo open space above the coal was found. This was probably because the gassier coals were stored in open-top Silos, which were better ventilated. Although the methane concentration in the open space above the coal pile was less than 1 pct for all 34 silos investigated, a methane measurement in the coal pile showed that high methane concentrations can exist. The methane released in the pile appears to accumulate and not liberate freely into the open space above the coal pile. Probably this gas is released during reclaiming operations, but further research is required to substantiate this claim.

Jan 1, 1978

By A. B. Needham

A number of the pegmatites in the southern Black Hills of western South Dakota contain sheet mica; and as the demand increased during World War II the area became an important producer of strategic qualities of mica. During this period of maximum activity, the U. S.. Geological Survey made detailed studies of the geological structural control, the mineralogical associations, and the production Of many pegmatites in the Black Hills. On the basis of results of this study, and at the suggestion of the Geological Survey, several of the pegmatites were examined by the Bureau of Mines, and a few were selected for further investigation. Accordingly, the White Bear, Silver Dollar, Buster Dike, and Hot Shot mines were diamond-core-drilled in 1947. The Hot Shot mine was investigated further by deepening the shaft and crosscutting the pegmatite in 1948. The mica-bearing deposits occur in lenticular intrusions of pegmatite in schists of various mineral composition. Eleven diamond-drill holes, totaling 2,111.4 feet in length, were completed on the four deposits. The shaft on the Hot Shot deposit was deepened 44 feet to the 112-foot level, and crosscuts were driven from the bottom of the shaft to the hanging Wall and foot wall of the pegmatite. This publication briefly describes the location, ownership, and history of the deposits and gives details of the work done by the Bureau of Mines and the Geological Survey.

Jan 1, 1950