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By K. O. Bennington

The thermodynamic properties of hedenbergite, of composition [(Ca0,9516) (Mg0,0583Fe2+0.7134 Fe3+0.0934 Mn0,1366) (Si206)], were experimentally determined at the Bureau of Mines. The standard enthalpy of formation determined by hydrofluoric acid solution calorimetry is AHf298 = -680.96±0.855 kcal/mol. The standard enthalpy of formation from the oxides is AR-96 = -24.55±0.485 kcal/mol. Low-temperature heat capacities were determined by adiabatic calorimetry from 12.3 to 300.1 K. The derived standard entropy is S-98 - 41.218±0.148 cal/mol-K. High-temperature heat capacities were measured with a differential scanning calorim¬eter from 397 to 1,147 K. These experimentally determined data were combined with data from the literature to calculate the Gibbs energies of formation and equilibrium constants of formation over the temperature range of measurements. Standard enthalpies of formation are given as a function of temperature. The standard Gibbs energy of formation at 298.15 K is AGf298 = -641.90±0.86 kcal/mol.

Jan 1, 1984

By D. E. Wolfson

This report describes the carbonizing properties of the principal coal beds of Allegheny County, Pa., which rank low in the high-volatile A bituminous classification. Seven coal samples from 3 coal beds were selected for study, as follows: 2 each from the Redstone and Pittsburgh beds and 3 from the Upper Freeport bed. Selection was based on estimated reserves. The samples of Upper Freeport and Pittsburgh coals were satisfactory chemically for producing metallurgical coke. The ash contents of the samples of Redstone coal were moderately high. One of the samples of Redstone coal was high in sulfur content, and it would be difficult to upgrade to meet present metallurgical standards.

Jan 1, 1959

By Alla D. Mah

The heat of combustion of aluminum carbide (Al, C3 ) , obtained directly by combustion calorimetry , was AH298.15 -1,029.6 ± 1.9 kcal / mole . == The heat of formation of aluminum carbide corresponding to this value was AH298.15 = -53.4 ± 2.0 kcal /mole .

Jan 1, 1964

By S. L. Windes

"INTRODUCTION For a number of years the bureau of Mines has been engaged in the detection, recording and interpretation of earth- and air-transmitted disturbances, man-made and natural, related to mining operations. For the measure¬ment of such disturbances, special equipment was developed (1, 2, 3, 4, 8) 3/ and results of the measurements have been reported (5, 6; 7,9).In general, the ranges of amplitude end frequency of vibration encountered and recorded in the earth-transmitted disturbances were 0.00005 to 0.1 inch and 5 to 5,000 cycles per second; in the air-transmitted disturbances, pressures ranging from 0.001 to 100 pounds per square inch and 0 to 20,000 cycles per second were recorded.One characteristic of the earlier tests was that either the arrival time of the disturbance to be recorded was predictable or the recording speed was slow enough so that the record covered extended periods of time (for example, 4 hours). As the investigations continued, it became apparent that a recording device was required that would respond to transient vibrations arriving at indeterminate times and at the same time provide a permanent record of displacement or acceleration versus time on a scale that would permit the analysis of waves having frequency components up to 10,000 cycles per second. A film or paper speed of 720 inches per second was found to be adequate, as this provides approximately 3/4 inch of record for each 0.001 second."

Dec 1, 1947

By Jack E. Fraley

Because of their noncombustibility, silicate and magnesium oxycements are desirable for sealing shale in underground coal mines. In this Bureau of Mines investigation, cement samples were cured and tested (nonstandard tests) for submersion to note resistance to dissolution (breaking into parts), which is an important property for a coating. Nonappreciable dissolution during 1 week of submersion was set for passing the test. Over half of the coatings passed the test.

Jan 1, 1977

By J. A. Pile, Virgil Miller, R. G. Peterson, F. B. Petermann

"INTRODUCTION As virtually no published data are available on the sintering of fine, minus-100-mesh, ferrograde manganese ores, it is most opportune to present data on the amenability of various fine ores and mill products to the sintering process. These data cover the sintering or nodulizing of finely crushed, high-grade pyrolusite and rhodochrosite ores, sintering of manganese carbonate flotation concentrate, sintering or nodulizing the calcine from the deleading of a manganese oxide flotation concentrate, and sintering the calcines made in a Herreshoff furnace from the treatment of manganese sulfate products.If finely sized products are to be smelted in the present electric or blast ferromanganese furnaces, they must be sintered or nodulized. The only specification as to the size of the sintered or nodulized product is that it must pass a 6-inch screen and not contain over 1t-1/2 percent minus 20-mesh material. The minimum-maximum size has not been established. Undoubtedly this opti mum size will be set by the ferromanganese industry when ample quantities of manganese oxide sinters have been smelted."

Mar 1, 1942

By J. R. Nettle

The electrodeposition characteristics of seven binary alloys of titanium have been investigated. The object of the electrorefining experiments with an alloy was to determine the efficiency of titanium separation from individual alloying elements under established conditions. Reported results are only indicative. It is conceivable that numerous duplications of tests might give average maximums that would vary from those noted in this report; however, in the few tests that were repeated, the magnitude of transfer of the alloying elements was of the same order. The results detailed herein are for a given set of conditions. Many combinations of operating variables are possible, and the results achieved under different conditions probably would differ from those reported.

Jan 1, 1958

By E. Robert Ruhlman

["Phosphate rock" is a broad term applied to natural deposits of minerals valued chiefly for their phosphorus content. More specifically, phosphate rock may be defined as a natural rock containing one or more phosphate minerals, usually calcium phosphate, of sufficient purity and in sufficient quantity to permit its use directly, or after beneficiation, in the manufacture of phosphorus-bearing products. The grade or quality of phosphate rock is expressed either in terms of its phosphorus oxide (P20S) content or the equivalent in tricalcium phosphate (Ca3(P04)2). The trade name for tricalcium phosphate is bone phosphate of lime (B. P. L.).]

Jan 1, 1958

By J. E. Fraley

Full-column anchored resin bolts were first used in underground mines in 1972. These bolts appear to improve support in many roof bolt applications, as indicated by the use of about 30 million resin bolts in 1980. In the mid-1970's, Bureau of Mines in-vestigators began looking for a substitute for resin because of its short supply and rapidly increasing price. The investigators selected accelerated gypsum plaster (CaSO. ·1/2H20), which becomes gypsum (CaSO.· 2H20) when mixed with water. Gypsum makes an effective alternate grout material because it hardens quickly, is readily available, and is inexpensive in comparison with other cementitious materials. The Bureau received a patent (U.s. patent 4,096,944) for a system combining water capsules (wax-encapsulated water) with plaster into cartridges resembling resin cartridges. This report presents the results of tests conducted by the Bureau on the plaster, the water capsules, and their combined use in cartridges. The tests were designed to determine how the gypsum-plaster water capsule bolting system performs and what happens in the hole while the bolt is being inserted through the cartridge. The test results indicate that water capsule plaster cartridges are a workable alternative to resin cartridges under normal or dry conditions.

Jan 1, 1987

This chapter summarizes data on crude mineral production for the United States, its island possessions, and the Commonwealth of Puerto Rico. Included also are tables that show the principal mineral commodities exported from and imported into the United States, and that compare world and U.S. mineral production. The detailed data from which these tables were derived are contained in the individual commodity chapters of volume I and in the State chapters of volume II of this edition of the Minerals Yearbook. Although crude mineral production may be measured at 'any of several stages of extraction and processing, the stage of measurement used In this chapter is what is normally termed "mine output." It usually refers to minerals or ores in the form in which they are first extracted from the ground, but customarily includes the product of auxiliary processing at or near the mines.

Jan 1, 1977

This chapter summarizes data on crude mineral production for the United States, its island possessions, and the Common- wealth of Puerto Rico. Included also are tables that show the principal mineral commodities exported from and imported into the United States and that compare world and U.S. mineral production. The detailed data from which these tables 'were derived are contained in the individual commodity chapters of volume I and in the State chapters of volume II of this edition of the Minerals Yearbook. Although crude mineral production may be measured at any of several stages of extraction and processing, the stage of measurement used in this chapter is what is normally termed "mine output." It usually refers to minerals or ores in the form in which they are first extracted from the ground, but customarily includes the production of auxiliary processing at or near the mines.

Jan 1, 1978

By Parviz F. Rad

The Bureau of Mines used a linear cutting apparatus equipped with a 7-inch disk cutter to cut grooves in marble, limestone, granite, and quartzite under a normal force of 7,000 lb. The size distribution of the muck for various grooves was determined through sieve analysis. A statistical search showed that Weibull distribution describes the size distribution better than other available functions. Results indicate that fineness modulus, chip population, and dimension of the largest chip can be used as indicators of cutting efficiency. The results correlate with those obtained from the boring machines and other lab experiments. Application of the principles established through this work to the operation of boring machines is explained

Jan 1, 1974

By Ann Hubbs, Vincent Castranova, Jane Y. C. Ma, De-Hwa Chao, Joseph K. H. Ma

AN OVERVIEW OF THE ACTION OF TETRANDRINE ON SILICOSISBecause of the persistent presence of silica dust in the lungs silicosis is a progressive and irreversible disease. At present, there is no proven effective therapy for silicosis. Limited choices of therapeutic intervention with corticosteroids and other immunosuppressive regimens 1,2 have been accepted for some forms of pulmonary fibrosis. These treatments are only minimally effective, and the results provide little understanding of the disease state due to the lack of correlation between drug activity and the mechanism of fibrosis. Thus, continuing effort must be made in the search for effective antifibrotic agents, which may be used to provide a sequential analysis of the fibrotic process and to open the door for further research and clinical development. Tetrandrine is one of hundreds of drugs screened for antifibrotic activity by Chinese scientists. It has been used in China as a treatment for silicosis in open clinical trials3 and in laboratory animals. The action of tetrandrine on pulmonary fibrosis has been attributed to its ability to inhibit particle stimulation of alveolar macrophages, a key cell type central to the fibrotic process, to release oxygen radicals and inflammatory cytokines. Alveolar macrophages (AM) residing on the alveolar wall, are the predominant phagocytic cells of the lungs responsible for pulmonary defense against inhaled microorganisms and other particles and thus play an important role in maintaining the homeostasis of the lungs. 7 Ample evidence suggests that cells of the monocyte-macrophage series play an important role in the immunopathogenesis of pulmonary fibrosis. When upregulated by silica, alveolar macrophages generate reactive oxygen metabolites8·9 which can damage lung parenchyma and release fibrogenic growth factors and cytokines, 10,11 such as interleukin 1 (IL-1), which can induce fibroblast proliferation and collagen synthesis. The cytokine-mediated fibroblast proliferation and collagen synthesis are key steps in the development and progression of pulmonary fibrosis .11 Previous studies by our group have shown that tetrandrine exhibits strong binding affinity to AM and inhibits particle-stimulated respiratory burst activity (oxygen consumption, superoxide anion release, and hydrogen peroxide secretion) in these cells. 13 In addition, studies by Kang et al. 14 have reported that tetrandrine inhibits silica-induced release of fibrogenic factors such as IL-1 which are capable of inducing fibroblast proliferation and collagen synthesis. Reist et al. 15 further suggested that the antifibrotic action of tetrandrine may be mediated in part by the direct effect of this drug on the ability of fibroblasts to respond to proliferative agents. These results indicate that the mechanism of silicosis involves activation of AM and fibroblasts by silica, resulting in abnormal collagen production due to miscommunications between the cell types. Tetrandrine may interrupt this process by direct interaction with the lung cells.

Jan 1, 1998

By L. A. Neumeier

The Bureau of Mines evaluated creep properties of Zn-Cu-Ti alloys that were annealed after finish-rolling either cold) or at 480° F (249° C). Compositions ranged up to 1.25 pct Cu and 0.36 pct Ti. Most data are for sheet annealed after finish-rolling to 92-pct total reduction. Annealing times were varied at temperatures between 320° and 560° F (160° and 293° C). For a number of the alloys, annealing after hot-rolling at 480° F affects creep properties very differently in longitudinal and transverse sheet directions. The detrimental result is that the anisotropy in creep properties between the two directions can be vastly increased. Conversely, specific annealing treatments of certain heavily cold-rolled alloys result in surprisingly low anisotropy in creep properties and the low anisotropy coincides with excellent creep resistance for both directions. Supplemental data are presented on tensile, hardness, and thermal expansion properties, and microstructures.

Jan 1, 1972

By Michael S. Miller

In 1987 and 1988, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied the 3,100-acre Borah Peak Wilderness Study Area (10-047-004) and a 708-acre parcel adjacent to the north in order to evaluate their identified mineral resources. The study area is located in Custer County, ID, about 18 mi northwest from MacKay. The study area lies along the western foothills of the Lost River Range and is underlain by quartzite, sandstone, shale, argillite, dolostone, and limestone. The Lost River fault, a major active fault, lies along the length of the study area. Large alluvial fans spread out from valleys originating east of the study area.

Jan 1, 1989

By Holmes, George H. Jr.

The Cherry Creek tungsten district was explored by the Bureau of Mines from April 16 to August 13, 1942. This district is in north-central White Pine County, Nev., 50 miles north of Ely. Principal work was done on the property of the Cherry Creek Tungsten Mining Co. and at the adjacent Chance mine, although the entire district was examined and mapped. The exploratory work was done in cooperation with the Federal Geological Survey and comprised surveying, trenching, sampling, long-hole and core drilling, rehabilitation of mine workings, road building, drifting, and shaft sinking. The more important tungsten occurrences were explored by trenching and diamond drilling. Sixteen holes, having a total length of 2,515 feet, were drilled. The project resulted in partial development of three new tungsten deposits and small increases in the reserve tonnage of two scheelite-bearing lenses that were being mined by the company. The following pages summarize the history of the district, outline the ownership of the properties explored, and describe the physical features and mineral deposits. Mining and milling practices at the Cherry Creek tungsten mine are outlined, and the plan and results of project work are presented in detail together with surface maps, assay maps, and drill-hole logs.

Jan 1, 1950

By Oliver Bowles

Slate possesses many admirable qualities, not only as a roofing material, but for blackboards, electrical switch boards, and for various structural uses such as stair trends, floor tile, baseboards, and sanitary enclosures. The American slate industry was established manor years ago, and has made remarkable progress, particularly during the past five years. One of the chief drawbacks to more rapid expansion is the high percentage of waste which reaches 75 to 94 per cent of gross production. Much of this waste is duo to rock imperfections over which man has no control, but a careful study of tae industry by the Bureau of Mines over a period of years indicates that an undesirably large percentage of the marketable slate is wasted in the processes of quarrying and manufacture. The initial step in quarrying slate is to separate from the solid ledge masses of a size that ray be conveniently removed from the quarry. This first step entails a greater waste of material than any subsequent process, and, therefore, invites the most earnest effort toward waste reduction. Attention has consequently been directed toward possible improvements in methods of making primary cuts in the quarry floor. A study of European practice with the wire saw, together with theoretical consideration of its advantages, convinced the writer that it possessed sufficient merit to justify its use as a primary slate cutter in American quarries. No practical conclusion in this matter could be reached except by experiment. Therefore, the desirability of obtaining equipment and trying it out under actual conditions of operation was urged upon operators. While no doubt the equipment could be readily manufactured in America, it had already been developed to the point of practical use in Europe; therefore the writer urged the desirability of purchasing one completely equipped wire saw in Europe, and determining through tests whether it gave sufficient promise of success to warrant its manufacture in America.

Jan 1, 1927

By G. W. Birge

Carbonizing properties of the principal coal beds of Perry County, Ky., are described in this Bureau of Mines report. Seven samples, representing the Hindman, Flag, Haddix, and Fire Clay beds, were carbonized by the Bureau of Mines-American Gas Association (BM-AGA) method, and yields of products and physical properties of cokes were determined. Carbonizing properties of blends of Flag and Fire Clay coals, with 20 and 30 percent Pocahontas No. 3 low-volatile coal from McDowell County, W. Va., also were determined. Expanding properties of the Flag and Fire Clay coals and their blends were determined in the Bureau of Mines sole-heated oven. The Perry County coals tested are high-volatile A bituminous in rank and, with the exception of the Hindman-bed sample, which contained excessive sulfur, were chemically suitable for metallurgical use. The three coals tested in the sole-heated oven contracted less than normal for Appalachian coals of similar rank, Blending the Fire Clay and Flag coals with 20 or 30 percent low-volatile coal increased coke strength appreciably but increased the expansion beyond normal limits for industrial blends.

Jan 1, 1962

By A. J. Forney

This report summarizes the findings of methods of treating caking coals in a fluid bed to destroy their caking properties. In batch tests it was found that several coals, including those with a free-swelling index greater than 8, could be decaed at temperatures from 400° to 425° C with a fluidizing gas composed of inert gas or steam containing 0.2 percent oxygen and a minimum residence LS,-;,' of 5 minutes. When treatment decreased the free-swelling index from about 8 to 1-1/2 or lower, the resulting treated coal was noncaking. In a continuous unit with continuous feed and discharge of coal, slightly more severe conditions were required to decake the coal. For 18- to 100-mesh coal a temperature of 430° to 440° C and an oxygen-to coal ratio of 0.4 cubic foot of oxygen per pound of coal feed was necessary. Finer mesh sizes required lower oxygen-to-coal ratios. In tests using air only as the fluidizing medium and treatment temperatures well below the softening range, the caking properties of 150- to 200-mesh coal were destroyed in 30 to 40 minutes of residence time at 200° C. Coarser sizes of 18 to 48, 48 to 100, and 100 to 150 mesh required longer residence time.

Jan 1, 1966

By GEORGE S. POPE

The purchase of coal by the Government under specifications depending on the heating value of the coal, its content of ash and of moisture, and other considerations, rather than upon the reputation or trade name of the coal, was based on the fuel investigations begun by the Technologic Branch of the United States Geological Survey in 1904. The plan was first adopted by the Treasury Department in 1906. Since then the plan, variously modified in form but the same in principle, has been gradually adopted by other departments until at present of the coal used by the Government, the total value of which approximates $8,000,000 annually, more than half is purchased under specifications. The Government publications dealing with the adoption by the Government of the specification plan, the number of contracts awarded on that basis, and the quality of the coal delivered under such contracts in the several fiscal years covered by the reports are given in publications listed at the end of this bulletin. Under the authority of acts of Congress making appropriations for analyzing and testing fuels belonging to or for the use of the United States Government, a laboratory is maintained at the headquarters of the Bureau of Mines, Washington, D. C., where samples represent- ing deliveries of coal purchased under specifications for Government use are analyzed and tested. At this laboratory more than 1,200 samples have been analyzed and tested in one month. With the complete equipment and the efficient force employed, the analytical work has been so perfected that the analyses and heating-value tests of the samples received are as accurate as may be reasonably expected in laboratory work of this nature. One of the serious drawbacks to the general adoption of the speci- fication method for the purchase of coal is the difficulty of obtaining at reasonable cost samples of coal that can be considered fairly repre- sentative of the commercial product delivered in wagons, railroad

Jan 1, 1913