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By H. C. Fowler

Hydrogen sulphide associated with the gasps and vapors from certain crude oils now produced in the United States has forced a serious health and safety problem upon the petroleum industry. Although the presence of hydrogen sulphide in or occurring with Mexican crudes has been known for some time, it was not until recently that crude oils which give off poisonous amounts of hydrogen sulphide have been produced to any extent in the United State. The injurious effects of this poisonous gas were first recognized by the refiners along; the Atlantic and Gulf Coasts upon receiving shipments of crude petroleum from Mexico. The problem of combating the hazards of the gases and vapors given off by this petroleum become more important as the use of Mexican crude increased. In 1925, the Bureau of Mines and Public Health Service under cooperative agreement with the American Petroleum Institute, studied the causes rend effects of hydrogen sulphide poisoning. Bureau of Mines Bulletin 2312 is report of this investigation, and although written with special reference to refineries, it nevertheless contains much information that is of value to the producer of petroleum.

Jan 1, 1927

By L. H. Adami

The heats of formation of anhydrous cadmium sulfate, cobalt sulfate, copper sulfate, nickel sulfate, and zinc sulfate were determined by hydrochloric acid solution calorimetry. The values at 298.15° K for formation from the metal, rhombic sulfur, and oxygen gas follow (cal/mole): CdS04J -222.0 ± 0.3; CoS04, -212.0 ± 0.4; CuS04) -183.4 ± 0.6; NiS04, -208.1 ± 0.2; and ZnS04, -233.1 ± 0.2. Corresponding heats of decomposition to form the metal oxide, sulfur dioxide, and oxygen were derived from these results; heats of decomposition to form the metal oxide and sulfur trioxide were also derived.

Jan 1, 1965

By Van E. Shaw, D. J. Bauer

Conversion of euxenite concentrate to sulfates with sulfuric acid and solvent extraction of the yttrium- rare - earth mixture with EHPA were studied to determine extraction and separation characteristics . Digestion with 3.5 pounds of 96 percent sulfuric acid per pound of concentrate at 336 ° C for 4 hours resulted in an easily handled product with a yield in excess of 98 per- A thorium- free product was obtained by calcining the sulfated material for 3.5 hours at 650 ° C prior to leaching with water . Di ( 2 - ethylhexyl ) phosphoric acid solvent is an effective extractant with preference for cerium ( IV ) and heavy - group rare - earth elements including yttrium . Separation of complex rare - earth mixtures into light- and heavy - group fractions is feasible , and these fractions can be further processed to isolate ytterbium , neodymium , and dysprosium by changing processing conditions to obtain separation factors greater than two between these and adjacent elements .

Jan 1, 1965

By C. H. Schack

Although viscosity is known to be important in processing and handling finely ground urea, its effect has never been fully quantified. This report describes the methods used and the results obtained in the initial phases of a broad investigation of the influence of viscosity of water suspensions of minerals in flotation, thickening, filtering, and other mineral-dressing unit operations. Several types of vis-cosimeters were tested before reliable and reproducible results could be obtained on mineral suspensions. After the viscosimeter used in the research was calibrated and standardized, tests were made on six pure minerals to study the relationship of pulp density, particle size, crystallinity, and cleavage on viscosity. An orifice-type viscosimeter equipped with a mechanical stirrer gave as good results as other types and was more flexible, faster, and simpler to operate. The orifice-type viscosimeter, when calibrated and standardized with glycerin and water mixtures, proved satisfactory over a wide range of viscosities. The accuracy and reproducibility were reasonably constant between 1 centipoise and 200 centipoises, the anticipated range in common mineral-dressing unit operations.

Jan 1, 1957

By Theodore Kessler

The purpose of this Bureau of Mines investigation was to determine what new organic compounds or high concentrations of a particular organic species can be formed by exposure of coal derivatives to ultrasonic energy. Tetralin, l-methylnaphthalene, and pyridine were used as model compounds. Gaseous and solid reaction products resulting from the ultrasonic irradiation of these coal derivatives were determined using mass spectrometry. Products from the irradiation of tetralin were studied as a function of time, atmosphere, and sample size. The sonolysis (chemical reactions produced by ultrasonic energy) of tetralin and l-methylnaphthalene produced C2H2, HCN, CH4, H2, CO, and CO2, depending upon the experimental conditions. The ultrasonic irradiation of tetralin also produced diacetylene under certain experimental conditions. The cleavage of organic chemical bonds by ultrasonic cavitation in the absence of water was also observed in this study.

Jan 1, 1967

By A. B. Needham

Graphite is a raw .material of considerable importance in both waxy and peace. Two types of graphite, classified according to particle size as flake and fines, are used, but the former is in much greater demand. The principal wartime use of graphite is in the manufacture of crucibles for melting brass and special alloys of copper and steel. Other uses in both peace and war are as lubricants, for foundry facings, and in paints, electrodes, batteries, motor and generator brushes, and a variety of other commodities. . This paper describes the operations of the Southwestern Graphite Co. of Los Angeles, Calif., which produces both flake and fine graphite from a property in Burnet County, Tex.

Jan 1, 1946

By Harold P. Rue

The problem of removing hydrogen sulphide from natural gas has become within the last few years one of major importance to the natural gas and petroleum industry. Several gas fields in the United States produce natural gas containing hydrogen sulphide, and a number of oil fields produce gas which contains hydrogen sulphide. 3 The percentage of hydrogen sulphide in natural gas produced in these fields varies from a fraction of 1 per cent to as high as 20.5 per cent by volume. Hydrogen sulphide is probably the most toxic gas associated with natural gas, and from the standpoint of health and safety it is important that the hydrogen sulphide be removed if the gas is to be used for domestic purposes. Hydrogen sulphide, besides being toxic and therefore a hazard to animal life, is under certain conditions an active corrosive agent and very destructive to equipment. The annual loss caused by the corrosive action of hydrogen sulphide on equipment amounts to hundreds of thousands, perhaps millions, of dollars. The largest percentage of natural gas produced in the United States comes from wells which also produce oil. This associated gas invariably carries with it light fractions of petroleum, which when separated from the gas, condense to the liquid form at ordinary temperatures and pressure. Commercial application is made of this natural condition, and "wet gas" is processed to obtain so-called natural gasoline by employing the principles of absorption, adsorption, or compression and subsequent expansion accompanied by cooling. In the manufacture of natural gasoline from wet gas which contains hydrogen sulphj.de, if this contaminating gas is not first removed, some of the hydrogen sulphide may oxidize to form free sulphur and water. The free sulphur will dissolve in the gasoline produced by any of the aforementioned methods and cause the product to be positive to the corrosion test and there-fore unsuitable for commercial use in that condition. The objectionable sulphur compounds can be removed by washing the gasoline with a solution of caustic soda or other chemicals, but this treatment is expensive. It is advantageous therefore to remove the hydrogen sulphide from the gas before it is processed in a natural-gasoline plant.

Jan 1, 1932

By Beverly W. Dunning

The effect of vacuum melting on the elimination of gases and nonmetallic inclusions for six low-alloy steels was investigated. The purpose of these studies was the analysis and comparison of differences in gas content and inclusions in air-melted and vacuum-melted steel. Data obtained from melts of 1-1/4 to 20 pounds indicate that vacuum melting decreases the number and size of nonmetallic inclusions and at the same time increases the degree of dispersion of the remaining inclusions. These improvements are undoubtedly related to the elimination of approximately 80 percent of the nitrogen and 90 percent of the oxygen as well as most of the undesirable metallic trace impurities.

Jan 1, 1961

By Valois R. Shea-Albin

An accurate assessment of the vertical stress on a coal seam at depth is important for mine design. Vertical stress calculation techniques presently available either are not sufficiently accurate or cannot handle complex surface topography. Therefore, the U.S. Bureau of Mines developed a computerized method to calculate vertical stress exerted on surfaces at depth that includes the effect of topography. Two input data sets are required: a digital elevation model containing topographic elevations and a coal seam file defining coal seam elevations at depth. Boussinesq's equation then quantifies the vertical stress resulting from topography. The computerized method was tested on a coal seam overlain by a complex topography where a vertical stress map encompassing several square miles was produced. Results show that depth mitigates the affects of surface topography, while the coal seam topography has a direct effect on the vertical stress. In comparison to the computerized method, the direct stress method overestimates stress under hills and underestimates stress under valleys. The largest difference between the two methods occurs under the steepest topographic relief. A limitation of the computerized method is that stresses cannot be accurately determined near an outcrop.

Jan 1, 2010

By C. C. Shale

Current-voltage relationships for air at high temperature in negative corona are compared with relationships predicted by theory. Deviations are discussed. Eased on the latest theoretical concept of electron detachment from negative ions and recent findings in basic research on free electron gases, results of applied research show the existence of free electrons in air at high temperature and high field strength-to-pressure ratios.

Jan 1, 1967

By R. V. Lundquist, H. Leitch

Two hydrated calcium aluminates , formed by side reactions in the leaching step and desilication step of the lime- soda sinter process , were investigated to better define their influence on alumina recovery . The two calcium aluminates , Caз [ Al ( OH) 6 ]₂ and зCa0.Al½ 03 · ( 8-12 ) H₂ ) , were prepared and identified by chemical and X- ray analysis . The relative proportions of each of these compounds formed in typical leach solutions at several temperatures were determined . The influence of free lime as a promoter of calcium aluminate formation was also investigated . The formation and precipitation from leach liquors of calcium aluminates contributes to the low alumina recoveries in the process . The presence of carbonate ion in the leach solution suppresses calcium aluminate formation and precipitation and results in higher alumina recovery . Hydrated calcium aluminates are formed in the aging of lime - soda sinters in the normal atmosphere .

Jan 1, 1963

By D. R. Tesarik

The factor of safety, the traditional measure of stability for earth embankments, is graphically presented in factor of safety charts in this Bureau of Mines report. Factor of safety contours are drawn for homogeneous earth embankments for two contrasting situations: (1) no phreatic surface and (2) a phreatic surface that assumes 10-pct freeboard. The factor of safety can be read directly from the charts if the physical properties of the soil and the geometry of the embankment are known. The curves provide a quick first approximation of the "most stable" and "least stable" condition of the embankment. The Simplified Bishop Method was used for the safety factor calculations, and a sequence of least squares curve fitting steps was used to present the factor of safety in final chart form.

Jan 1, 1981

By John Nagy

Tests were conducted in the Experimental coal mine to study some of the factors that should be considered in fighting mine fires and to obtain data on the effectiveness of different types of extinguishing agents. The investigation was confined to class "A" fires in a zone 20 feet long, involving coal burning on the floor, on the floor and ribs, and on the floor, ribs, and roof of the mine entry. It was determined that the time elapsed between ignition and attack of the fire is very important. A fire in the early stages was found to be controlled more easily and quickly than a similar fire that had burned longer. It was also found that, under suitable conditions, a fire in the floor, ribs, and roof develops very rapidly and consequently might spread over a considerable area if not brought under control quickly. The ventilating current affects fire-controlling operations markedly. Attack in intake or fresh air is highly advantageous, the chief inconvenience being the radiant heat from the fire. Attack in direct return air was impossible for the fires tested in this investigation, because of the high temperature. Universal-type gas masks for noxious gases and smoke offered no protection against the intense heat. Approach to a fire in the return air behind a water-fog curtain is not feasible unless the direction of air flow can be reversed. In one" test fresh air was carried to the fire area with a line brattice. Although the entire controlling operation was in fresh air and masks were not necessary, it was considerably more difficult to control the fire than when a similar fire was attacked in intake air.

Jan 1, 1950

By Heinz W. Sternberg

The literature on electrochemical treatment of coal is reviewed, and possible avenues of further research in this field are discussed in this report. Electrolytic reduction of finely distributed coal resulted in the addition of as many as 9 atoms of hydrogen to 100 atoms of carbon. Reduction of coal extracts at controlled potentials indicated the presence of condensed aromatic hydrocarbons and reducible quinones in coal. As much as 65 percent of low-rank coal can be made alkali soluble by electrochemical treatment. Higher rank coals gave smaller yields of alkali-soluble products. However, the nature of this reaction is not clear. The difficulty of reducing coal electrolytically is probably due to the insolubility of coal and not to any structural peculiarity. Reduction of coal by electrolytically generated radical anions appears to be a promising approach for further research.

Jan 1, 1962

By H. E. Perlee

Autoignition temperatures and limits of flammability of nine halogenated hydrocarbons in atmospheres of air, oxygen, and nitrogen tetroxide were measured in a modified standard autoignition apparatus and limit-of-flammability apparatus previously developed at the Bureau of Nines. Of the nine halogenated hydrocarbons investigates--bromochloromethane, bromotrifluoromethane, bromochlorodifluoromethane, 1,1,2-trichlorotrifluoroethane, 1-bromo-l-chloro-2,2,2-trifluoroethane, dibromodifluoromethane, l,2-dibromo-1,1,2,2-tetrafluoro-ethane, 1,1,1,3,3-pentachlorotrifluoropropane, and l-bromo-2,4-dichloro-1,1,2, 3,3,4-hexafluorobutane--two formed flammable mixtures with nitrogen tetroxide and six with oxygen; none formed flammable mixtures with air. Three of the halogenated hydrocarbons formed no flammable zones with any of the three oxidizing atmospheres. For those halogenated hydrocarbons that supported combustion in oxygen atmospheres, explosion pressures developed during constant-volume burning of mixtures near the middle of the flammable zone were observed to range from about 6 psig for dibromodifluoromethane to 158 psig for 1-bromo-1-chloro-2,2,2-trifluoroethane. In all cases, the calculated burning velocities of these mixtures were less than 8 in/sec.

Jan 1, 1966

By B. J. Scheiner

Oxidation procedures based on the chlorine-hypochlorite system were investigated for improving gold recovery from carbonaceous gold ores. The oxidation pretreatment prior to cyanidation was accomplished by (1) addition of sodium hypochlorite to ore pulp, (2) by addition of chlorine to ore pulp, and (3) by generation of hypochlorite in situ by electrolysis of a brine solution used to pulp the ore. Gold extraction of 90 pct was achieved by cyanidation of carbonaceous ore that had been pretreated with 20 Ib per ton sodium hypochlorite at 50° C for 4 hours. Similarly, pretreatment of the ore pulp with 35 1b chlorine per ton at 24° to 30° C and 15 hours reaction time resulted in 89-pct gold extraction by subsequent cyanidation. Concomitant studies showed that electrolyzing the pulp prepared with a brine solution was equally as effective as electrolyzing hypochlorite and chlorine for oxidizing carbonaceous ore constituents that are deleterious to cyanidation. Gold extraction of 90 pct was obtained by electrolysis when 275 lb of are was treated at 200 amp for 7 hours in an 8-to 10-pct salt solution. Power consumption was in the range of 60 kwhr per ton.

Jan 1, 1972

By Ernest Ph. Hérivel

The mine and treatment plant of the Teziutlan, unit of the Mexican Corporation, S. A., are located at Aire Libre, in the District of Teziutlan, near the northwest edge of the State of Pueblo, Republic of Mexico. The property is leased from the Teziutlan Copper Co. The town of Teziutlan is the terminus of a branch railroad starting from Oriental Junction or the Mexico-Jalapa-Veracruz narrow-gage system of the National Railways of Mexico. A branch line 18 km in length from Teziutlan to Aire Libre belongs to the Teziutlan Copper Co. and is leased and operated in conjunction with the mine.

Jan 1, 1933

By R. V. Ramani

This report is volume 1 of an eleven-volume final report for a Grant completed by The Pennsylvania State University for the Bureau of Mines to develop a dynamic general purpose computer simulation model for underground coal mining. The simulator developed under the Grant has a wide range of possible applications in the design and evaluation of underground coal mining systems from the standpoints of health and safety, productivity, and mine environment. The Master Design Simulator consists of nine free-standing function-oriented subsystem models linked together into an integrated, comprehensive model of an entire mining system. The subsystems comprising the Master Design Simulator include geology and reserves, methane generation, roof support, subsidence, production, rail haulage, cost, water generation, and ventilation. This volume of the final report contains a statement of the purpose and scope of work of the Grant, and provides an overview of the Master Design Simulator with a brief description of each subsystem. Also included is a discussion of several areas of application for the simulator.

Jan 1, 1975

By J. A. Herdlick

The Star mine, near Neihart, Cascade County, Mont., has been in continuous operation since the construction of a 50-ton bulk flotation mill in 1939. The mine was examined by G. N. Bennett, an engineer of the Bureau of Mines, in November 1942. At that time the life of the operation appeared to be limited and a program of crosscutting and core drilling were recommended. The program had as its objective the investigation of a promising undeveloped area lying west of the Star vein and, if possible, the development of enough reserves in this area to insure continuous operation during the war emergency. Development of additional reserves would then justify necessary changes in the mill in order to eliminate the heavy penalties imposed for excess zinc in the bulk concentrates. The Bureau of Mines work began in February 1944 and was completed in September 1944. The project was started by Wilder R. Brinton and continued by Thomas W. Oster, mining engineers in the Bureau's Montana district office. Beneficiation tests on are and concentrates were made after completion of the underground work. This report presents the factual data obtained during all phases of the Bureau's investigation.

Jan 1, 1949

By C. A. Frenzel

Extensive spectroscopic data are needed in making reliable vibrational assignments for use in calculating thermodynamic functions of polyatomic molecules. The fundamental vibrations of organic molecules may be observed at any wavelength from 2.5 to 200 microns (micron = µ = 10-4 centimeters), but most often in the region from 3µ to 50µ. Raman spectra generally cover the range in which fundamental vibrations occur, but equally important infrared spectra usually are not measured at wavelengths longer than 25µ. This limitation results because most infrared spectra are determined for analytical purposes, which seldom require information outside the region 2µ to 25µ. Measurements of infrared spectra in the range 15µ to 35µ recently were begun by the Bureau of Mines to obtain data needed in making vibrational assignments. This report presents the spectra of the following thirteen compounds: Tetrahydrofuran, 1-methylpyrrole, piperidine, 2-methylpyridine, 3-miuthylpyridine, 2-propanethiol, cyclopentanethiol, 2-methyl-2-butanethiol, 3,3-dimethyl-2-thiabutane, cyclohexanethiol, cyclopentyl-l-thiaethane, 2,4-dimethyl-3-thiapentane, and hexamethyldisiloxane.

Jan 1, 1960