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By N. E. Hanna

Originally developed for use in coal mines where on-shift blasting with explosives was prohibited, compressed-air blasting has been used for the past 15 years as a substitute for fixed explosives. With the current commercially available compressed-air systems -Airdox and Armstrong -coal is dislodged by a high-pressure discharge of air from a pressurized shell placed in the coal borehole. In the original systems stationary compressors were mounted on the surface or in the underground ventilated areas. These proved so successful that a mobile compressor unit was developed for use at the working face. Because of the possibility that such a unit might operate in a gassy atmosphere, the Bureau of Mines has investigated the hazards associated with operation under conditions where firedamp could accumulate in explosive concentrations. ACKNOWLEDGMENTS Grateful acknowledgment is made of cooperation of C. E. Carter, H. R. Hiller, R. E. Kennedy, H. Kohn, H. D. Metzinger, J. Mahoney, J. Nickovich, G. So Scott and I. Spolan in the experimental work.

Jan 1, 1956

By Arne Landsberg

Accessory metals, although valuable resources, present possible environmental concern in the smelting of base metals. The Bureau of Mines, U.S. Department of the Interior, has undertaken research to define the chemistry involving these metals. Arsenic in copper smelting is the first to be investigated. Roasting, the first step in many copper smelters, was chosen for initial investigation because of the potential for arsenic removal in this primary process. Simple, static-bed, vaporization experiments were devised to obtain the data in this study. Ancillary transpiration and mass spectrometry were also used to delineate conditions necessary for arsenic volatilization from a roaster feed. For nearly complete arsenic removal, a temperature of 650°-700° C, a reducing atmosphere including carbon monoxide, and a source of sulfur were found to be essential.

Jan 1, 1980

By C. H. Riggs

THIS REPORT give's the results of a study of the central and south parts of the Cushing oilfield, including a description of the geology, a review of the production history, and estimates of oil reserves available by secondary-recovery methods. Each of the major producing zones of the field is treated separately. The report, which is one of a long series of field studies the Bureau of Mines has conducted over the past 40 years, was prepared to aid operators to increase oil recovery and to help prevent underground waste in the Cushing field, in the State of Oklahoma, and in the United States. The geology and production history are presented not as a review of past behavior of the Cushing field but rather to interpret the possibilities for increased oil recovery by future development of this and similar areas. The field, which is in the northwest corner of Creek County, Okla., was discovered in 1912 and developed during 1913 and 1914. For several years it, was one of the most important areas producing high-grade crude oil in Oklahoma. Although some oil has been recovered from each of 10 separate reservoirs, nearly 98 percent of the total recovery of oil in the area studied was from 4 major producing formations (table 1). Of these, only the Bartlesville [ ]

Jan 1, 1958

By E. C. Lane

[The motor gasoline that s being marketed in the United States this summer slightly more volatile then that sold a year ago. This increase in volatility is shown by a general lowering ref the average distillation rang, of about 2°F. During the post 10 years the Bureau of Mines has made semiannual surveys of the gasoline marketed in the United States, the survey just completed being the twentieth in the series. The 12 cities in which samples were collected have beer chosen as representative of the more important marketing territories, as it is obviously impracticable to obtain a sample of every gasoline sold in the entire country.]

Jan 1, 1929

By M. Mentser

The exchange of oxygen between carbon dioxide and carbon monoxide that occurs reversibly on carbon surfaces was studied at temperatures of 750° to 850°C and a pressure of 1 atmosphere. Carbon-14 was used to detect and measure the exchange reaction. The extent of oxygen exchange was a linear function of com- position of the gas mixture, and this relationship was used to evaluate the forward and backward rate constants of the reaction. Equilibrium constants, directly determined for oxygen exchange in this study, agreed well with values in the literature that were derived only by indirect procedures. This result establishes the validity of oxygen exchange in the mechanism of carbon gasification by CO2. Rates of carbon gasification were less than an order of magnitude slower than rates of oxygen exchange. Activation energies for these two processes were 58 and 53 kcal/mole, respectively. The closeness in the activation energies argues against any change in the rate-controlling step over a wide temperature span at atmospheric pressure. The role of CO as a retardant on the CO2-C reaction, and the nature of the carbon-oxygen complex are also discussed in view of the data obtained.

Jan 1, 1973

By Laurence G. Trudell

A geologic framework for interpreting stratigraphic and geographic variations of the Green River Formation in the Piceance Creek Basin is developed from lithologic data accumulated by the Bureau of Mines from oil-shale coreholes. From detailed Bureau of Mines descriptions of samples from nine coreholes and supplementary lithologic data from seven additional sampled sections, three cross sections were constructed along lines transecting the basin. Plotted as lithologic columns with corresponding oil yields and resistivity logs, the sampled sections are correlated on a time-stratigraphic basis. Distribution and correlation of nahcolite and halite zones are shown, and the approximate base of leaching of these saline minerals is indicated. General lithologic characteristics of members and zones are discussed and interpreted. Large-scale lithologic logs illustrate the nine Bureau of Mines core descriptions, and the complete description of Bureau of Mines-Atomic Energy Commission Colorado Corehole No. 1 is included in an appendix. The time-correlated cross sections provide a necessary framework for understanding the depositional history of the Green River Formation and will facilitate evaluation of oil shale and other mineral resources in the Piceance Creek Basin.

Jan 1, 1970

By J. W. Lyman

The U.S. Bureau of Mines investigated methods of separating valuable rare-earth materials from Fe in neodymium iron boron (NdFeB) magnet scrap. A selective oxidation treatment of the scrap oxidized the rare-earth portion while leaving elemental Fe. Magnetic and leaching procedures were tried for separating the metallic Fe and rare-earth oxides, but the extremely fine grain size of the oxidized scrap prevented recovery by either technique. The best separation of rare earths from bulk NdFeB magnet scrap was obtained by dissolution with H2S04 followed by precipitation of recyclable rare-earth salts. By precipitating neodymium-alkali sulfate double salts as an intermediate that can be converted to a variety of useful products, many materials-handling and economic disadvantages found with direct precipitation with fluoride or oxalate were avoided. Iron was removed from magnet leach solutions by precipitation as a jarosite, eliminating a major disposal problem. Research was also conducted with contaminated mixed SmCo5 and NdFeB swarf. Using a flotation-leaching technique allows the SmCo5 to concentrate in the froth, while the grinding-medium contaminant sinks and is removed as tailing. The NdFeB is dissolved by H2S04 during the process.

Jan 1, 2010

By W. W. Fowkes

The Federal Bureau of Mines examined a low-temperature tar obtained from a small-scale commercial unit for carbonizing North Dakota lignite for products that might be important to the economic processing of the tar. Tie tar may be divided into three distinct parts: (1) Tar acids, 45 volume-percent; (2) tar bases, 1 volume percent; and (3) neutral compounds, 54 volume-percent. It has a boiling range of approximately 150° to 380° C. (the decomposition temperature) and yields 18 weight-percent as hard pitch. The tar distillate up to 365° C. may be separated as: (1) Tar acids, 48 volume-percent; (2) tar bases, 1 volume-percent; and (3) hydrocarbons, 51 volume-percent. The tar-acid distillate, boiling to approximately 265° C., was characterized in some detail; the neutral fractions and the tar bases were less thoroughly examined. In general, as might be expected of a primary low-temperature tar, the lower boiling fractions are less in quantity compared with the usual high-temperature tar. The homologous series of each major class appears to be rather complete, although some components are present in very small amounts. The tar is quite unstable thermally, and might be more conveniently processed by extraction methods rather than by distillation procedures. The neutral fraction of the tar is highly aromatic, and might be considered as base stock for the production of liquid fuels.

Jan 1, 1961

By A. Aly Selim

This report describes the feasibility of predicting percussive drilling rates by equations derived from statistical regression analysis. The least squares statistical method was used and the analysis was performed both by direct and by stepwise linear regression analysis. The predicted penetration rate is a function of the drill power and the physical properties of the rocks penetrated. The results show promise that the technique may be of value in providing a mathematical model by which percussive drill manufacturers and users can predict the performance of a given drill. Experimental work involved two mining type percussive drills. Penetration data for these drills were determined from nine rocks drilled in the laboratory. Drill work rates (power) were determined in a separate series of experiments. Rock physical properties were measured from diamond-drill core samples taken from the same blocks used for percussive drilling.

Jan 1, 1970

By D. A. Baker

This report describes the elemental characterization of chromite and related materials at the Bureau of Mines, Albany Research Center. Analytical methods for determining the major constituents, representing extensive experience, refinement, and development, are described and fully annotated. This presentation should allow other laboratories to use these methods and obtain comparable results with a minimum of time needed for familiarization with individual methods.

Jan 1, 1990

By E. R. Palowitch

Coal wasted with mine refuse represents losses in overall recovery of merchantable coal to the mine operator and a concomitant reduction in domestic reserves of available coal. Fraser, Kelley, and Graham3/ in studying the available coal in mine refuse in the Pittsburgh district of western Pennsylvania have estimated that at least 1 ton of mine refuse is produced for each 10 tons of merchantable coal and that 20 percent of this mine refuse might be recovered as salable coal by mechanical cleaning. SUMMARY This investigation dealt with the mechanical recovery of coal from wine refuse by a dense-medium washery employing pulverized mine rock as the dense medium and operating at a rate of 175 tons per hour. Two types of mint refuse were tested: Freshly mined and that .which had been mined 2 years before and piled on a waste dump.

Jan 1, 1955

By Catherine C. Kilgore

The Bureau of Mines investigated the availability of lead and zinc from 104 domestic mines and deposits. Fourteen primary lead and fifty-three primary zinc operations with in situ demonstrated resources containing 27.3 million metric tons (t) of lead and 53 million t of zinc were subsequently evaluated. Potentially 17.5 million t of lead and 2.4 million t of byproduct zinc could be recovered from 14 primary lead operations. Economic evaluations performed in constant January 1982 dollars determined a long-run total cost per pound of recoverable commodity. Including a 15-pct discounted-cash-flow rate of return (DCFROR), 59 pct of primary lead was potentially available at or below $0.32 per pound of lead. Potentially 40 million t of zinc and 5.6 million t of byproduct lead could be recovered from 53 primary zinc operations. Ninety percent of the recoverable zinc is potentially available from currently nonproducing mines and deposits, and a weighted average of their long-run total costs was determined at $0.98 per pound of zinc. At a breakeven (0-pct) DCFROR, these non producing operations had a weighted average long-run total cost of $0.58 per pound of zinc. Sensitivity analyses illustrated that operations that recover byproducts were most sensitive to fluctuating metal prices, producing operations were more sensitive to increased smelter treatment charges, and nonproducing operations were impacted most by the DCFROR.

Jan 1, 1983

By Norma Golumbic

The primary purpose of the Bergius (hydrogenation of coal) and Fischer-Tropsch (hydrogenation of carbon monoxide) processes is the production of synthetic liquid fuels. This objective is of importance in insuring an adequate supply of motor fuels and lubricating oils in the United States. In the urgency of the basic research and process development work on synthetic liquid fuels, the possibilities for the production of synthetic chemicals inherent in these processes have hitherto received little attention in this country. However, the by-products, as well as the primary products, from the Bergius and Fischer-Tropsch processes are rich source materials for organic chemicals. The overhead oil from liquid-phase hydrogenation of coal, for example, contains benzene, toluene, xylene, cyclohexane, methylcyclohexane, aromatic solvents, about 20 percent tar acids (largely phenol, cresols, and xylenols), and 3 percent nitrogen bases. Wax, alcohols, and acids are by--products of the Fischer-Tropsch synthesis. In addition, techniques have been developed which make possible the production of aliphatic hydrocarbons, alcohols, acids, aldehydes, and other oxygenated organic compounds. These chemicals are more valuable on a unit basis than gasoline. Because of continued rapid expansion of the plastic, resin, lacquer, and solvent industries, larger amounts of many of these chemicals will be needed in the near future.

Jan 1, 1949

By M. A. Elliott, H. H. Schrenk, L. G. Berger, John C. Holtz

"INTRODUCTION Interest in the possibility of using Diesel 6/ engines for haulage power in mining and tunneling is increasing in the United States, owing largely to the reported successful use of Diesel locomotives in European coal mines and to the comparatively recent development of automotive Diesel engines in this country. The extent of this interest has been evidenced to the Bureau of Mines by numerous requests for information as to the factors that must be considered if Diesel engines are to be used safely underground.Proponents of the application of the Diesel engine to underground haulage base their claims for its safety upon a comparison with the gasoline engine, assuming that (1) the carbon monoxide content of Diesel exhaust gas is always low and that (2) fire and explosion hazards from Diesel fuel are minimized because of its low volatility. In these respects the Diesel engine appears less hazardous than the gasoline engine, whose use underground has been discouraged by the Bureau of Mines and other organizations interested in safety in mining. However, such generalizations cannot be accepted as conclusive evidence that safety is inherent in Diesel engines in underground service, as European experience indicates that certain hazards may accompany their use. Such hazards were discussed in a previous publication 7/ that reviews developments in the use of Diesel locomotives in European coal mines.The Bureau of Mines has initiated a study of the hazards that may attend the use of Diesel engines underground to obtain first-hand information that may serve as a basis for recommending sale practices under conditions existing in the United States."

May 1, 1940

By W. L. Crentz

Before Korea was partitioned along the 38th parallel following World War II, the coal fields of South Korea, with the possible exception of the Samchok area, were not considered important to the industrial needs or Japan or Korea. Much of the demand for electric power in South Korea was met by hydroelectric installations north of the 38th parallel. Following cessation of hostilities between Japan and the' Allied nations in 1945, hydroelectric power continued to flow into South Korea from the north until 1949, when the North Koreans severed the power lines into South Korea, thereby forcing that section of the country to depend almost entirely upon coal to generate electric power.

Jan 1, 1953

By T. J. Ballard

"The Hog Creek mine, in lot 92 of the 17th district in Towns County, Georgia, was examined in 1890 by F. P. King, who reported the existence there of a 4-foot vein of corundum. The mine is about 2 miles west of Hiawassee, on the southern side of Ramey Mountain. Ed Burch, of Hog Creek, holds the surface rights, and the mineral rights appear to be vested in the heirs of William R. McConnell, who formerly owned and prospected the property.Examination by the Bureau of Mines showed the workings to be caved, but it was thought advisable to open the mine and uncover the reported vein. The Bureau's work consisted, of trenching and cleaning out the pits and shaft.William R. McConnell, the former owner, prospected the property in about 1890. At some tine during that operation, the prospect was visited by Francis P. Kings a geologist with the Georgia Geological Survey.3/King reported that a 4-foot vein of corundum was exposed g feet below the surface in the main cut and was opened for 20 feet along the strike. He also reported that the so-called ""Georgia rubies"" were taken from this mine.The main mine is about 2,000 feet- north of Hoc Creek on a timbered southern slope of Ramey Mountain. It lies at an altitude of about 2,100 feet, approximately 100 feet above the high-water level of the Catuga reservoir, which floods Hog Creek to a quarter of a mile above its confluence with the Hiawassee River. The nearest water is a small branch about 1,000 feet to the west.Chlorite schist is the principal host rock. It has been intruded by irregular masses of a very herd periodtite rock possibly troctolite. The schist near the surface is extremely weathered, presenting white and red laminations parallel to the schistosity. At a depth of 40 feet in the cross-cut it appears as a fine-grained green-chlorite schist. The schist strikes about N. 350 E. and dips 800 to the southeast.No corundum vein was found, and if any existed it must have been mined out after King's visit. In the pit, about 15 feet west of the shaft, approximately 150 pounds of zoisite and an occasiona1 small crystal of corundum were found imbedded in schist about 18 feet below the surface, near hard, dense troctolite."

Mar 1, 1946

By E. R. Palowitch

This report is the result of a series of coal-cleaning tests using a dense-medium cone-type washer. Detailed results are given for 2 tests using a magnetite medium and 4 tests using a pulverized-refuse medium. Approximately 120 float-and-sink tests and over 500 separate chemical analyses were made in conjunction with these tests. In these tests higher recovery efficiencies and sharper separations were obtained when using a magnetite medium, especially on coal sizes below one-half inch. When sizes above 1 inch at low specific gravities of separation are cleaned, the pulverized refuse medium compared favorably with the magnetite medium.

Jan 1, 1956

By W. B. Berwald

The United States Bureau of Mines, in cooperation with the Natural Gas Department of the American Gras association, has been studying actively for the past several years the problem of the flow of natural gas through high-pressure transmission lines. Numerous data on gas flow through pipe lines under many conditions of operation have been obtained by carefully conducted tests, and these data, together with all other available information, have been analyzed carefully to secure practical facts for the use of operators in designing pipe lines and determining the effects of different operating conditions on pipe-line capacities. The first procedure in initiating; this problem was to review, compile, and analyze all of the existing data on the flow of natural gas through pipe lines. Actual data applicable to pipe and operating conditions normally used in the transmission of natural gas were meager, and the several pipe line flow formulas developed by different investigators gave widely varying; results when applied to problems of pipe-line design. Therefore, further experimental work under conditions comparable to those found in transmitting natural gas was essential before any definite recommendations could be made.

Jan 1, 1931

By W. B. Berwald

The United States Bureau of lanes, in cooperation with the Natural Gas Department of the American Gas Association, has been studying actively for the past several years the problem of the flow of natural gas through high-pressure transmission lines. Numerous data on gas flow through pipe lines under many conditions of operation have been obtained by carefully conducted tests, and these data, together with all other available information, have been analyzed Carefully to secure practical facts for the use of operators in designing pipe lines and determining the effects of different operating conditions on pipe-line capacities. The first procedure in initiating this problem was to review, compile, and analyze all of the existing data on the flow of natural gas through pipe lines. Actual data applicable to pipe and operating conditions normally used in the transmission of natural gas were meager, and the several pipe line flow formulas developed by different investigators gave widely varying results when applied to problems of pipe-line design. Therefore, further experimental work under conditions comparable to those found in transmitting natural gas was essential before any definite recommendations could be made. The problem, as originally planned, included flow tests on pipe lines in operation, and in each test the measured delivery vas to be compared with the delivery calculated from several common pipe line flow formulas.

Jan 1, 1931

By M. B. Boyer, C. H. Herty, F. A. Hartgen, G. L. Frear

"DEFINITION OF VISCOSITYViscosity has been defined as the resistance experienced by one portion of a liquid moving over another portion, such as one molecular plane moving over an adjacent plane. A measure of viscosity is the force required to keep one plane in motion at Unit velocity, the other plane being considered stationary. Figure 1 illustrates the general idea that the surface friction between two adjacent areas will be greater the larger the molecules. Therefore it may be assumed that viscosity will be increased by molecular association or agglomeration, and likewise dissociation rill decrease viscosity. According to Maxwell (1)6 the unit of viscosity, the poise, is the tangential force per square centimeter of area of either of two horizontal planes 1 centimeter apart, one of which is fixed while the other moves with unit velocity, the space between being filled with viscous liquid of unit viscosity.The need for a satisfactory apparatus and experimental procedure for the determination of viscosity of high-melting materials at temperatures corresponding to those in pig-iron and steel making has been recognized during the past few decades. The condition of the slag during the smelting and refining periods in the iron- and steel-making processes exerts an important influence on the metal product obtained, this slag condition really meaning the state of viscosity or, vice versa, fluidity, which the slag attains under certain conditions."

Jun 1, 1934