Search Documents

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 A. W. Frolli

This paper, describing the mining and reduction methods and costs at the Oceanic quicksilver mine, is one of a series of similar reports being prepared by the Bureau of Mines on various mines in the United states. The property, which is owned and operated by the Anglo American Mining Corporation, Ltd., is 5 miles east of Cambria, San Luis Obispo County, Calif. It lies in a region of steep hills and sharply incised canyons on the west slope of the Santa Lucia Range at an elevation of about 500 feet above sea level. The climate is ideal for living and operating conditions. A 40-mile paved highway connects the mine with San Luis Obispo, the nearest convenient railroad town.

Jan 1, 1937

By A. B. Hooker, P. G. Guest, E. J. Gleim

"From time to time the United States Bureau of Mines has received reports of gas explosions alleged to have been caused by correctly assembled flame safety lamps. In most of the mines where the explosions occurred the lamp was in use at a working face where the velocity of the ventilating current would be relatively low. The inference has been that the lamp was correctly assembled but that the gauze became sufficiently overheated to ignite the surrounding atmosphere.As part of its routine investigation of flame safety lamps the Bureau of Mines subjects each lamp to a test in still and moving atmospheres to determine its safety. Heretofore, as long as the lam, successfully passed this and other tests no determinations as to the margin between success and failure were made; hence, in attempting to answer inquiries concerning the reported explosions it was found desirable to be able to give actual gauze temperatures as a measure of the comparative safety of lamps under various conditions. The previous laboratory tests of flame lamps in still mixtures were made in a chamber or ""gallery"" of relatively small volume where the lamps might have been subject more or less to the smothering effect of the combustion products. It was therefore decided to make a special series of tests to obtain the gauze temperatures of both bonneted and unbonneted lamps in still and low velocity mixtures, using a larger gallery to offset any smothering effect.These tests are believed to represent the first attempt at measuring gauze temperatures by means of themocouples. The results will not only be of interest but will also be helpful to many in determining the status of flame safety lamps relative to gas ignitions in mines."

Feb 1, 1929

By R. C. Annear

This report describes open, sublevel, and shrinkage stoping at the Greenwood mine, operated by Inland Steel-Co. The iron ore mine is in Marquette County, Mich., about 6 miles southwest of Ishpeming (fig. 1). The Greenwood is one of three active underground hard-ore mines on the Marquette range, the others being the Cliffs-Shaft and the Champion mines. The operation reflects an achievement in exploiting small, difficult-to-mine hard-ore bodies lying beneath a 200-foot overburden of glacial drift, which is partly water bearing. This report can indicate only briefly the efforts of personnel in overcoming adverse conditions in mining more than 2 million tons of ore, 80 percent of which was in lump form, for open-hearth production of steel. Significant data presented include descriptions of the principal mining methods employed, sublevel and shrinkage stoping; percent aged mining costs for the entire year 1957, covering both direct mining costs and general expenses; and performance records in units of labor, power, and supplies.

Jan 1, 1960

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

"K. A. DIGREGORIO, E. v. CILENTO, AND R. c. LANTZ. Measurement of superoxide release from single pulmonary alueolar macrophages. Am. J . Physiol. 252 (Cell Physiol. 21 ): C677-C683, 1987.-An electrooptical method was developed to quantify superoxide (02) release from single rat pulmonary alveolar macrophages (PAM) during adherence to the bottom of a culture dish. This was done by measuring the reduction of nitro blue tetrazolium (NBT) to a diformazan precipitate at 550 nm from videorecorded images of individual cells. Temporal changes in cell optical density, which are proportional to the mass of diformazan produced, were calculated from videophotometric measurements of the change in light intensity over individual cells. Total diformazan produced increased 78 and 1263 with an increase in NBT from 0.5 to 1.0 and 2.0 mg/ml, respectively. Total diformazan produced and maximum rate of production among individual PAM varied two- to threefold providing strong evidence for heterogeneity in 02 production. Specific inhibition of 02 production by superoxide dismutase, iodoacetate, and chlorpromazine significantly reduced the total diformazan produced and maximum rate of diformazan production. Hydrogen peroxide was not involved in NBT reduction, since catalase alone did not significantly change diformazan production. This novel method to quantify 02 release from single PAM should be valuable in analyzing heterogeneity and single cell kinetics of O; production, in assessing the effects of exposure of cells to particulates on O; release, and in relating release to electrophysiological measurements.rat; nitro blue tetrazolium; macrophage heterogeneity; single cell kinetic PULMONARY ALVEOLAR MACROPHAGES (PAM) protect the lungs by phagocytizing foreign debris and bacteria (24). This process involves ingestion as well as destruction of foreign matter. Phagocytosis is usually accompanied by a respiratory burst that increases cellular oxygen consumption and glucose metabolism in the hexose monophosphate shunt (7), which leads to the release of highly reactive oxygen metabolites at the surface of the · plasma membrane (6, 27). These agents have been implicated in the killing of bacteria by phagocytes (22), but have also been shown to be toxic and have been linked to cancer, emphysema, arthritis, diabetes, and other diseases (17, 22, 30). Toxic effects may be a result of either an abnormally low production of metabolites, resulting in damage to lung tissue by respirable bacteria and dusts, or an abnormally high production, resulting in direct damage to lung tissue by metabolites themselves."

Jan 1, 1989

By Clark F. Grain

The monoclinic to tetragonal inversion of zirconium dioxide was studied by single-crystal X-ray methods, high-temperature X-ray diffractometry, and differential thermal analysis. The unusual features of the inversion, such as no definite transition Lperature, hysteresis, and athermal kinetics, were confirmed for powders who mean crystallite size was greater than 1,000 A. Samples of mean crystallite size below 1,000 A displayed classical kinetics, obeying a logarithmic rate law. A detailed mechanism based on Ubbelohde's theory of continuous phase transformations was proposed which is consistent with all the experimental facts.

Jan 1, 1965

By H. D. Jacobs

The Bureau of Mines undertook a research program to insure an adequate supply of iron raw materials for future iron and steel making needs. A sample was obtained of oxidized taconite from the western Mesabi Range in Minnesota, and the metallurgical response of the taconite to beneficiation by a process that included selective flocculation-desliming-cationic flotation was evaluated. The sample contained 35.3 pct iron and represented approximately 2 billion tons of crude material. Selective flocculation and flotation were evaluated in a pilot plant with a feed rate of 900 Ib/hr. Concentrates averaging 61.7 pet iron and 5.1 pet silica were obtained, with an accompanying iron recovery of 67.2 pet. About 83 pct of the process water requirements were reclaimed from the slime and froth tailing and then recycled.

Jan 1, 1980

By J. W. Horne, W. B. Shirey

"INTRODUCTION The United States Bureau of Mines in cooperation with the State of Colorado at the University of Colorado has conducted experiments to determine the amount and composition of the noncondensable gases evolved when crude shale oil is distilled under pressure.Hydrogen sulphide is one of the components found in the complex mixture of gases produced by the distillation of shale oil under pressure. This paper deals with the apparatus and method used in determining the amount of hydrogen sulphide evolved in the laboratory experimental cracking stills.The study required a complete extraction of all the hydrogen sulphide from the gas stream after it left the water-cooled distillate condensers and before the as stream entered the charcoal absorber for removing the light naphtha. In devising the method it was necessary to take into account a constant variation of velocity, pressure, and percentage of sulphide in the total gas stream coming from the still.Ordinarily, the quantitative determination of hydrogen sulphide in Gas is made by analyzing small samples taken at regular intervals. This estimation can be accomplished by use of the Bunte gas burette as modified by Tutriler,4 or by a similar method. In the industries where the flow of as is constant end of uniform composition, this practice is sufficiently accurate for plant control. For experimental work where many variables have to be taken into consideration, as in the case at hand, these methods are not applicable."

Oct 1, 1931

By John B. Gayle

The suitability of fluid petroleum coke as a blending agent for producing metallurgical coke has been investigated using the Tuscaloosa and sole-heated experimental ovens. From the results of tests with three representative blends, it has been fond that additions of fluid petroleum coke effect the following changes: (1) Increase in size, resistance to shatter, and apparent specific gravity of cokes produced; (2) little or no change in coke hardness and stability or in the amount of breeze formed; (3) increased charge density; (4) modification of expansion characteristics of blends charged; and (5) decreased ash and increased sulfur contents of blends charged and cokes produced. Substitution of a calcined sample of fluid coke of greatly reduced sulfur content resulted in a coke of inferior physical properties. This effect indicates that additions of the calcined product should probably be limited and that other methods for producing a low sulfur fluid coke should be considered.

Jan 1, 1956

By R. E. Green

The Bureau of Mines undertook a bench-scale study of three different types of oxidized taconites3 from the Lake Superior district to improve the dispersion-selective flocculation-desliming process for beneficiating these materials. The response-surface contours of the effects of dissolved ionic species in the water and of three dispersion systems on the selective flocculation process were studied. Results of metallurgical data and chemical analyses of the aqueous phase showed that the water quality affects the performance of the selective flocculation process.

Jan 1, 1984

By John A. Organiscak

Enclosed cabs are a primary means of reducing equipment operators? silica dust exposure at surface mines. The National Institute of Occupational Safety and Health recently performed a laboratory study to evaluate which factors on an enclosed-cab filtration system are most significant. The various factors evaluated were intake filter efficiency, intake air leakage, intake filter loading, wind infiltration, use of a recirculation filter, and the use of an intake pressurization fan. The result of this laboratory testing has shown that the two most important factors for an effective filtration system on an enclosed cab were the efficiency of the intake filter and the use of a recirculation filter. A higher-efficiency intake filter considerably increased the quality of the intake air that was delivered into the enclosed cab. It also was determined that air leakage around the intake filter notice-ably reduced its air cleaning effectiveness. The second key factor is the use of a recirculation filter, which was shown to improve the air quality in the enclosed cab by six to 12.7 times more than the intake filter alone. The reason for the significant improvement was that the cab air was constantly drawn through the recirculation filter, thus continually filtering the dust out of the air.

Jan 1, 2010

By Wilbur I. Duvall

A linear array of shot and gage holes 30 feet deep in a granite outcrop was used to compare the size and shape of radial strain pulses produced in the rock when short cylindrical charges of cast composition B were detonated axially or at one end. The axially detonated charges produced radial strain pulses that had shorter rise times and larger peak strain than the strain pulses produced by end detonated charges.

Jan 1, 1965

By Thomas C. Mowatt

Chemical and petrographic studies were carried out on selected tin-bearing rock samples of contact-metasomatic origin from the Cassiterite Creek and Brooks Mountain areas, Seward Peninsula, Alaska. The tin content of rocks ranged from 0.39 to 8.9 pct. Leaching with a 20 pct hydrochloric acid solution released from 19.3 to 67.9 pct of the tin. Cassiterite was not observed in the rock samples. These results are significant with regard to tin recovery and reserve delineation in these and similar occurrences. Part of this leachable tin may be associated with metasomatic borate minerals.

Jan 1, 2011

By K. J. Liles

The Federal Bureau of Mines conducts a comprehensive test program on clay and shale at the Tuscaloosa Metallurgy Research Center. All samples are subjected to standard preliminary ceramic tests, which include firing formed briquets at temperatures ranging from 1,000° to 1,250° C to identify firing range and colors, and quick-firing to determine bloating characteristics. Materials that shop potential as structural products are further tested after either extrusion or dry-pressing. If the quick-fire test is positive, bulk samples can be fired in a rotary kiln to evaluate their potential as light- weight aggregate A number of miscellaneous tests also can be conducted if requested. These tests determine properties such as refractoriness (pyrometric cone equivalency), oil-bleaching characteristics, oil absorbency, viscosity for drilling-mud applications, sand-bonding properties for foundry usage, and pelletizing characteristics.

Jan 1, 1977

By J. M. Kuchta

Experimental data are presented on the autoignition temperature (AIT) characteristics of the hydrocarbon jet fuel, JP-6, in various oxygen-nitrogen atmospheres under conditions of constant volume and constant pressure. AIT's of this fuel in air varied little with fuel injection pressure but increased greatly with decreasing fuel content at low fuel-air-ratios. They also increased with decreasing oxygen content of the fuel vapor-oxidant atmosphere. Consistent with thermal ignition theory, the ignition temperatures increased with decreasing initial pressure, ignition delay, and vessel radius; expressions are given which define the observed variation of AIT with these variables for JP-6 fuel vapor-air mixtures. The significance of autoignition temperature data obtained using various ignition criteria is discussed to show the usefulness of such data in evaluating fire and explosion hazards. In addition, data are presented on the extent of oxidation that occurs prior to autoignition of this fuel in air at various temperatures.

Jan 1, 1965

By H. Dolezal

An investigation was made on the use of magnesium for the direct reduction of rutile to make low-cost, offgrade titanium which could be upgraded to an acceptable grade of metal by electrorefining. Reductions made with charges containing magnesium chloride under hydrogen yielded products with oxygen con-tests close to the theoretical equilibrium composition. Two reduction products were made from rutile for use in electrorefining amenability tests: (1) a product from reduction in an inert atmosphere which contained 88.9 percent titanium and 4.42 percent oxygen, and (2) a product from reduction in a hydro-gen atmosphere which contained 92.5 percent titanium and 2.40 percent oxygen. Reduction products obtained under both of these conditions were amenable to electrorefining.

Jan 1, 1965

By Tell Ertl, Ernest E. Burgh, John R. Wagner

The principal goal of the Oil-Shale Mining Division is to develop the most economical methods and practices for mining oil shale. Experimental work in the mine has not progressed far enough to conduct full-scale breaking tests; therefore, mining season - to October 31, 1945, has been confined largely to problems connected with drilling cost oil shale. Calculations have indicated that commercial production will result in breaking the oil shale; the largest individual turn will be for drilling. This paper is a report on the progress of phase two of drilling research to date; it outlines the development of a successful hard-surfaced rock bit for drilling oil shale.

Dec 1, 1948

By D. B. Gawthrop, A. Taylor, G. St. J. Ferrott

"This paper presents data obtained as part of an investigation of the explosive properties of ammonium nitrate. During the course of the work: it was found desirable to investigate the sensitizing action of nitrostarch in mixtures of ammonium nitrate containing low percentages of this material. Data were derived as to the sensitivity to decomposition by heat and the completeness of detonation and,of detonation of straight ammonium nitrate, as compared with ammonium nitrate-nitrostrarch mixtures containing 1 to 10 per cent of nitrostarch.The ammonium nitrate was a sample of coated material obtained from the salvage of amatol shells. Its analysis was as follows:"

Feb 1, 1930

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 P. Kovalchik

The Bureau of Labor Statistics (BLS) classifies hearing loss as a separate illness category. Hearing loss accounted for 11% of all illnesses in 2005 (U.S. Department of Labor Bureau of Labor Statistics, 2006a). According to occupational data for coal mining provided by the Mine Safety and Health Administration (MSHA) from 2000 to 2005, operators that exceeded 100% noise dosage were from only seven types of machines: auger miners, bulldozers, continuous mining machines, front end loaders, roof bolters, shuttle cars (electric) and trucks (Title 30 CFR Part 62, 2000-2005). Roof bolting machine operators rank second among all underground machine operators that exceed 100% noise dose. There are approximately 600 underground coal mines with 3,930 roof bolting machine operators (U.S. Department of Labor, Mine Safety and Health Administration, 2005; U.S. Department of Labor Bureau of Labor Statistics,

Jan 1, 2008