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By L. C. IlsLey

Cooperation between the United States Bureau of Mines and the Safety in Mines Research Board of Great Britain, continuous, since 1924, s made possible this and other papers on safety subjects. Grateful acknowledgment is made to representatives of the board for their assistance in arranging visits to several mine-safety stations, and to F. R. Wynne, Deputy Chief Inspector of Mines, for arranging visits to mines in Great Britain and certain other countries in Europe. During the summer of 1927 the writer had the privilege of visiting the mine-safety testing stations An Great Britain, Belgium, Germany, and France, in the order named. All of these countries have large coal mines, many of which are rated as gassy. Therefore, a the installation of electrical equipment is contemplated each of these countries is confronted with the same safety problem as is the United States that is, the development of electrical equipment that will not, ignite gassy atmospheres should they through neglect or accident surround the equipment. The means employed by these countries in safeguarding gassy mines should therefore be of general interest to safety engineers of American coal mines, and a brief survey is given for each of the four countries mentioned. The fourth or last of these surveys covers conditions in France.

Jan 1, 1929

By Joseph J. Wallace

1. From the standpoint of known recoverable reserves, the following is the order of importance of the beds: Upper Kittaoning, Lower Kittanning, Upper Freeport, Lower Freeport, Middle Kittaning, Clarion, Pittsburgh, and Redstone. 2. mown measured and indicated reserves in all beds, based on a minimum thickness of 14 inches and on 1,800 tons per acre-foot of coal in place, me estimated at 1,859 million short tons as of January 1, 1952. Of this, 1,351 million short tons me in beds 28 inches and more thick. Areas in each bed were omitted from the estimates because available data relative to the bed characteristics are too meager to make an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total estimated reserves.

Jan 1, 1953

By J. P. Walsted

The lack of an iron-smelting industry in the Pacific Northwest places the ferrous metals industries under an economic handicap. No iron-smelting enterprises, now dormant, had been operated successfully. Iron made at both of hoes installations proved to be satisfactory for normal pig-iron uses. Electric power and reductants acre available in the area. Power from the dames now completed and. those being constructed insures present and future needs for basic industries. Subbituminous coal, close to the main supply of iron ore, insures ample reluctant for all smelting requirements.

Jan 1, 1954

By Mary F. Koehler

Interoxidic compounds, such as vanadates, have not been studied extensively in the field of thermodynamics. This is a report of three vanadates of sodium--metavanadate, pyrovanadate, and orthovanadate. Vanadates of other metals will be considered in future reports. The heats of formation at 298.15° K. of the three sodium vanadates (both from the oxides and from the elements) were derived from the results of sodium hydroxide solution calorimetry. Free energies of formation were obtained by combining heat and entropy values. The results support the conclusion that the three sodium vanadates were stable with respect to all possible decompositions in which vanadium retains its pentavalency.

Jan 1, 1960

By N. S. Dalal, X. Shi, V. Vallyathan

"Correlated spectroscopic and cytotoxicity measurements were made on newly crushed silica to find whether the fracture-induced, silicon related (Si-0· or Si· type) free radicals play a direct role in the mechanism of hemolysis by silica particles. The free radical content of the silica particles was controlled through the radical decay, thermal annealing, and boiling processes, and was followed with electron spin resonance spectroscopy. Portions of the same sample were evaluated for their hemolytic potential, employing sheep erthyrocyte and optical absorption techniques. The results indicate little, if any, correlation between the amount of the silicon-based radicals and the hemolytic potential of the fresh dusts, but these or related radical sites might be contributors to silica cytoxicity and fibrogenicity via peroxidative pathways .INTRODUCTIONIn an earlier convnunication (1.) from our laboratory it was reported that mechanical crushing of coal and quartz under normal air atmosphere generates free rad;cals on the particle surfaces, and that these radicals decay with time, hence pointing to a higher toxicity of fresh dusts in relationship to pneumoconiosis and silicosis. More recently Fubin; et al.(2) have also reported the detection by electron spin resonance (ESR) of the formation of SiO· and Si·-type of radicals from quartz particles crushed under atmospheric conditions. In agreement with earlier ESR studies on single crystals of quartz crushed under high vacuum (10-10 torr) (3) and subsequent exposure to air (3), and to other gases (4), these radicals were identified (2) as being formed by the hemolytic cleavage of the Si-0-Si bonds and the reactions of the Si· and SiO· ,radical with atmosphere. Fubin; et al. (2) also suggested that these radicals might be involved in the mechanism of the fibrotic action by silica, either by transforming the particle surface into a selective oxidating agent or as an initiator of a sequence of reactions leading to fibrosis. Earlier Gabor and Anea (5) had reported that lipid peroxidation caused by free radicals on the silica surface might be involved in the red blood cell membrane damage. Thus far, however, no parallel cytotoxicity, fibrogenicity, and free radical studies on a given Quartz dust sample have been reported, except for some earlier work from our laboratory (1,6,7). We now present more recent results obtained from parallel cytotoxicity, fibrogenicity, and free radical measurements on a freshly made quartz dust. The dust’s free radical content was measured using ESR spectroscopy while its cytotoxicity poteni1al was estimated via hemolysis. Hemolysis was employed as the tox1c1ty test because it 1s a widely used method for estimating the potential of a dust for disrupting the cell membrane (8). The f1brotic potential was followed.by measuring the dust-induced lipid perox1dat1on. us1ng linole1c ac1d as a model lipid. As discussed below, the results obtained suggest new clues.to the mechanism of the Quartz-related cytotoxicity and fibrogenicity."

Jan 1, 1988

By George D. Drechsler

The purpose of this review is to provide an analysis of the supply and demand for coal in Europe in 1955-56 and estimates of future growth in European requirements as a medium for appraisal of the effects and benefits to the economy of the United States. This review stems from observations and evaluations made in contacts with Government and industry representatives of the principal countries of Europe and is based on detailed data selected from the established flow of unclassified economic and statistical material originating in overseas areas for use and deposit in the Bureau of Mines, Foreign Solid Fuels Section. This material includes current reports and analyses prepared by the United States Foreign Service, official reports of individual countries, foreign industry and trade publications, and the committees of the several European organizations engaged in continuing review and study of problems relating to fuels and energy. The review is presented in four sections: 1. Discussion of the more important factors relating to the present and future fuels and energy position of Western Europe.

Jan 1, 1957

By S. H. Katz

In the Bureau of Mines investigations of respiratory apparatus, a laboratory study of dust respirators has been conducted, and the results will be published in detail as a technical paper. Many industrial dust respirators, and many fabrics and filtering materials were tested. The principal results of these tests, and the conclusions drawn from them, are presented below. Reference to the patent literature discloses numerous types of dust respirators, mostly based on the filter principle. The present study included only representative filter-type respirators, purchased on the market.

Jan 1, 1926

By N. S. Dalal, X. Shi

"Electron spin resonance (ESR) spin trapping methodology has been used to study the reactions of manganese dusts with glutathione, employing a-{4-pyridyl-1-oxide)·N-tert-butyl-nitrone (PBN) and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as spin traps. The results show evidence for the glutathionyl radical formation in the reactions of both MnO2 and manganese (Ill) acetate with glutathione. Based on these experimental observations, we hypothesise that the mechanism of neurotoxic effects of manganese might be due to the fact that the generation of glutathionyl radicals depletes the glutathione pool and reduces the glutathione shield against free radical products of dopamine metabolism and manganese induced reactive oxygenated species. IntroductionExposure to manganese compounds often occurs as the result of foundries and mining operations (1. 2). Other significant sources of environmental manganese include coal-fired power plants and burning of residual and crude oil (3, 4). Lately gasoline combustion has also started to contribute since manganese (methyl cyclopentadienyl manganese tricarbonyl. 0. 125 g/gallon) is being used instead of lead as an antiknock ingredient in automobile fuels (5. 6). Although manganese is an essential element in certain biological processes it is toxic in excessive amounts. The manganese toxicity is mainly associated with the nervous system (7-9). Symptoms frequently observed in manganese poisoning or manganism are disorientation, memory loss, anxiety, compulsive laughing and crying, mask-like faces, akincsia rigidity and tremor (10). In spite of numerous investigations to understand the mechanism of manganese induced injury. it has not been possible to localize the initial chemical lesion responsible for altered physiology and ultimate cell death. This may perhaps he the reason for failure in developing a successful therapy for manganese intoxication."

Jan 1, 1990

By Miles B. Royer

The experimental blast furnace has attracted increasing interest during the past decade as a practical means for investigating a broad range of blast-furnace smelting problems. Under experimental-furnace conditions, information can be obtained with less expenditure of time and raw materials and, therefore, at lower cost than comparable information could be obtained under industrial operating conditions. Furthermore, the experimental furnace may be operated beyond the range of smooth operation, even to failure, to delineate the limits of operability. Such deviation from normal operating practice would be economically intolerable in industrial operations where production and operating stability might be disrupted. The Federal Bureau of Mines experimental blast furnace at Bruceton, Pa., near Pittsburgh, has been operated and under development since 1951. However, the usefulness of this experimental data to industrial practice was somewhat nebulous in early experiments, and the correlation of the experimental blast furnace with the industrial blast furnace was not known.

Jan 1, 1961

By W. H. Ode, W. A. Selvig

Low-temperature distillation tests at 200°, 350°, and 500° C. were made on a subbituminous coal from Boulder County, Colo., and a subbituminous coal from Weld County Colo., in connection with a survey of carbonizing properties of American coals 4/ and investigations of their chemical and physical properties. 5/ The coal represented by the sample from Weld County was reported to give off combustible volatile matter at unusually low temperatures when placed on a fuel bed. The yields of tar and oil and the composition of the as from this coal, as obtained in the distillation tests, did not confirm this report. These yields and the gas composition of the Weld County coal differed but little from those obtained from the coal from Boulder County. Both coals yielded tar and gas in amounts considered to be normal for coals of their rank.

May 1, 1937

By C. Gary Reiness

A safety glass eyepiece which had been repeatedly exposed to mine environment over a number of years was studied to determine some of its optical properties. In the regions from 385 to 400 mµ and from 625 to 760 mµ, the transmittance was less than the 89 percent required by the American Standard Safety Code for Head, Eye, and Respiratory Protection. From 200 to 320 mµ the relative transmittance of two parts of the eyepiece was found to vary widely, having a maximum of 38 percent difference at 315 mµ. Irradiation of the glass by ultraviolet light caused enhanced absorption in the range from 200 to 1,200 mµ. There was a time-dependent increase of 1016 color centers per cubic centimeter throughout this range after 36.5 hours of irradiation. The rate-of-growth curve for the optical density, at 243.5 mµ and 23° C, was resolved into linear and saturable components, indicating zero order and first order

Jan 1, 1968

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

"Using. ESR spin trapping methodology, evidence was obtained that fresh quartz dust in a cell-free aqueous medium generated hydroxyl - and possibly superoxide radicals. The hydroxyl radical generation potential decreases on storing of fresh quartz dust in ambient air and on the addition of either catalase, superoxide dismutase, desferoxamine, or DMSO. The role of quartz related radicals in the biochemical mechanism of acute silicosis is suggested from these findings.IntroductionThis report summarizes our electron spin resonance (ESR) detection of oxygenated radical formation by freshly crushed quartz particles in a cell-free aqueous medium, and its inihibition by radical scavengers. This study was undertaken with to elucidate the primary biochemical mechanism involved in the development of silicosis (Farber, 1983; Reiser and Last, 1979; Silicosis and Silicate Disease Committee, 1988). In particular the mechanism by which the quartz particles exert their toxic action on cells and the process(es) by which these actions progress to fibrogenesis are still not well understood (Farber. 1983; Reiser and Last, 1979;). It is generally believed that the action of quartz particles on the cell membrane is the starting point of the silicotic process (Farber, 1983; Parazzi et al., 1968). Thus the surface characteristics of the quartz particles have been the subject of several recent studies (Bolls et al.. 1983; Dalai et al., 1986; Fubini et al., 1987). Recently, We reported that mechanical crushing of quartz under normal atmosphere generates free radicals which decay with time, and that these free radicals are associated with a higher cytotoxicity of fresh quartz dust as compared to aged dust from the same stock (Dalai et al., 1986; Vallyathan et al.. 1988). The formation of Si• and. SiO--type of radicals from quartz particles crushed under atmospheric conditions has also been reported by Fubini et al. (1987). In addition, Gulumian and van Wyk (1987) have reported that quartz particles react with hydrogen peroxide (H202) to generates hydroxyl radicals (•OH) and suggested that this process might contribute to quartz's pathogenicity. However, these authors did not report the effects of metal chelators, so it was not clear as to whether the detected -OH radicals simply resulted from the Fenton reaction involving exogenous metal ion contaminants. Earlier, Marasas and Harington (1960) reported that quartz particles could function as an oxidant in a number of in vitro oxidations, including the hydroxylation of proline and lysine. They postulated that silica dusts, on reacting with water, could release H2O2 which might have the potential to react with various biological constituents and thus cause tissue damage. In fact, Gabor and coworkers (Gabor and Anca, 1974; Gabor et al., 1975) suggested that the cytotoxicity of quartz particles might be associated with the generation of some 'factor or factors possessing the properties of a free radicals capable of promoting the peroxidative chain cleavage of polyunsaturated fatty acid moieties of the phospholipids in the cell membrane. More recently Weitzman and Graceffa (1984) reported that asbestos is able to catalyze the generation of • OH radicals from H2O2. Their later work indicated that lipid peroxidation may be one of the mechanism by which asbestos produces tissue injury (Weitzman and Weitberg, 1985). This is significant because • OH radicals are capable of causing peroxidation by abstracting hydrogen atoms from cell-membrane lipids and initiating lipid peroxidation in lysosomal membrane (Fong et al., 1973). In fact, the formation of oxygenated species in reactions involving quartz was suspected since Kolbanev et al. (1980) reported the detection of H2O2 in the reaction of fresh quartz particle with aqueous medium. The present work was thus undertaken to detect the anticipated formation of some oxygenated, radical species by reactions of quartz in a cell-free media and its inhibition by radical"

Jan 1, 1988

By B. J. Dalton

Several relationships between coexisting phases for analytical binary solutions near the critical point are given. These relationships were developed from a consideration of a (G u, P) surface at constant temperature and a (G u, T) surface at constant pressure, where G is the molal Gibbs free energy, u is the concentration of component 1 expressed as a mole fraction, G is the pressure, and T is the temperature. These formulas should facilitate the calculation of some of the quantities useful in making thermodynamic consistency checks on phase equilibria data about the critical point.

Jan 1, 1970

By L. B. Pankratz

High-temperature heat-content values of gallium and scandium sesquioxides were measured over the temperature range from 298° to 1,800° K. The results fill gaps in the thermodynamic information for these compounds; no previous similar data existed. The heat-content values were combined with heats and entropies of formation to obtain free energies of formation of gallium and scandium sesquioxides to 2,000° K. The thermodynamic stabilities of the sesquioxides of aluminum, gallium, scandim, and yttrium were compared.

Jan 1, 1963

By S. L. May

Tantalum and columbium can be extracted from several of their ores or concentrates by chlorination procedures. Direct chlorination of high-grade minerals in the presence of carbon at temperatures between 500° and 800° C will extract up to 99 percent of the tantalum and columbium. Metallurgical beneficiation of low-grade source materials by carbothermic reduction produces a ferroalloy that is amenable to chlorination at a temperature of 500° C. Over 90 percent of the tantalum and columbium can be recovered.

Jan 1, 1965

By Jon I. Voltz

The U.S. Bureau of Mines has conducted fundamental coal fragmentation studies to evaluate the effects of impact energy and direction of bedding planes on dust generation, size distribution, and impact-output energy relationships. Product size distributions were obtained for the fragmented samples by screening to minus 150 mesh. The minus lS0-mesh fines were analyzed with a light scattering photometer with a measurement range of 176 to 1.9 /.tm. Increased input energy produced a significant increase in the weight of plus 3/8-in material for impact perpendicular to the bedding planes. No significant trend was observed for parallel impact. Impact direction had little influence on dust size distribution, and input versus output energy relationships. As expected, total airborne dust measured at time of impact and percent particulates below 11 /.tm in size generally increased with increased input energy for both directions of impact. Energy used for sample fragmentation increased with increased energy input.

Jan 1, 1989

By L. E. Schultze

[The Bureau of Mines conducted bench-scale studies to develop techniques for stripping tetravalent cerium from tri-n-butyl phosphate solutions. Experiments were conducted in a constant-temperature bath using beakers and mechanical stirring. Ninety-five pct of the cerium was stripped from a 50-pct tri-n-butyl phosphate 50-pct kerosene solution containing 0.18 M cerium in 15 minutes at 50° C using 0.11 M aqueous formaldehyde.]

Jan 1, 1974

By Charles W. Huggins

DEVELOPMENT of the electron microscope has permitted man to examine many small objects that could not be resolved by the light micro-scope. Diffraction, spherical aberration, and chromatic aberration are the main factors that limit resolution to about two-tenths micron with the light microscope. No matter how perfectly a light microscope is constructed and operated, it cannot possibly resolve points separated by less than two-tenths micron. Rapid development following World War II has produced many electron microscopes capable of 20 A resolution. Fibrous inorganic minerals are well suited for electron microscopic study. Many micrographs of chrysotile have been published, but electron microscopic study of the amphiboles has been somewhat neglected. New techniques in sample preparation have simplified the study of fibrous material. Ultrasonic energy has been very helpful in sample dispersion. This publication contains a representative group of electron micrographs of natural inorganic fibers that have industrial value. These fibers commonly are referred to as the asbestiform minerals. The Bureau hopes that the knowledge gained through electron microscopy and other scientific study of the natural inorganic crystalline fibers eventually will lead to the production of synthetic fibers that will satisfy the requirements of industry.

Jan 1, 1959

By N. S. Dalal, B. Jafari, F. H. Y. Green, M. M. Suryan, V. Vallyathan

"Freshly ground and aged anthracite and bituminous coal samples were investigated by electron spin resonance (ESR) spectroscopy to detect the presence, concentration and reactivity of free radicals. Freshly ground anthracite coal produced greater concentration of free radicals than the bituminous coal, and the radical reactivity was also greater for the anthracite. The reactivity of the newly produced free radicals in the anthracite dust correlated with the dust's toxicity. Furthermore similar coal-based free radicals were detected in the lung tissue of autopsied coal miners, suggestive of persistent reactivity by the embedded coal dust leading to the progressive disease process. Results of the studies on the severity of coal workers' pneumoconiosis (CWP) and free radical concentration m lung tissue support this hypothesis.INTRODUCTIONCOAL WORKERS' PNEUMOCONIOSIS (CWP) has been an important topic of concern to miners, mining engineers, epidemiologists and medical researchers for decades. It is well known that the prevalence and severity of CWP differ markedly between different regions and mines despite comparable exposures to respirable dust (REISNER and RoBOCK, 1977; HURLEY et al., 1979). These variations in pathogenicity of coal mine dusts can only partially be explained by differences in the mineral composition and by rank of coal (CHRISTIAN and NELSON, 1978; CHRISTIAN et al., 1979; HATCH et al., 1980). Cytotoxity studies on mammalian cells do not correspond well with the human disease pattern (CHRISTIAN and NELSON, 1978; CHRISTIAN et al., 1979; HATCH et al.,1980; VALL YA THAN et al., 1988). For example, while epidemiological studies of coal miners (REISNER and ROBECK, 1977; HURLEY et al., 1979) indicate that the prevalence of CWP correlates roughly with the rank of coal, such correlation has not yet been established in biological studies, despite considerable effort (CHRISTIAN and NELSON, 1978; CHRISTIAN et al., 1979; HATCH et al., 1980). In order to help resolve this apparent paradox we have undertaken a systematic study to evaluate whether any correlation exists between the concentration of free radicals present in fresh or aged coal dusts from two well-characterized U.S. coals. This study was also prompted in part by observations reported in the literature that organic free radicals can be formed on the surface of freshly fractured coals (LEBEDEV et al., 1978; DULIBA and CLARKSON, 1984). In particular, ARTEMOV and REZNIK (1980) noted that the decay lifetimes and, hence, the reactivity of the organic free radicals formed on crushing Russian coals, .depended"

Jan 1, 1989

By Philip C. Good

The Bureau of Mines investigated the feasibility of utilizing low-grade phosphatic shale as a feed for phosphoric acid production. Present practice in the phosphate mining operations of southeastern Idaho is to remove and either stockpile or waste low-grade phosphatic shales as the high-grade phosphate beds are selectively mined. Acid digestion studies were performed on uncalcined shale and on shale calcined to remove free carbon to determine phosphoric acid quality, yield, and amenability to filtration. The untreated shale, containing 21.4 pct P205, was digested with sulfuric acid in a single-tank reactor to yield phosporic acid and gypsum residue. Although 96 pct P205 recovery was attained in digesting uncalcined shale, only the calcined product gave satisfactory filtration rates. Calcined shale yielded phosphoric acid recovery of about 93 pct of the contained P205. It was higher in impurities than commercially prepared acid derived from high-grade western phosphate rock. An acid filtration rate of 745 lb P205/ft2/day was attained. This value is lower than the rate of 900 lb P205/ft that is generally considered to be acceptable in industrial production of phosphoric acid from high-grade phosphate rock.

Jan 1, 1981