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By K. O. Bennington

The thermodynamic properties of aegirine, of composition [(Na0.869Fe30+7362 Fe20+16Mn0.03Ca0.1121)(A10.141Sil 9738)(06)], were experimentally determined at the Bureau of Mines as part of its efforts to advance minerals technology. The standard enthalpy of formation determined by hydrofluoric acid solution calorimetry is AHf298 = -641.12±0.73 kcal/mol. The standard enthalpy of formation from the oxides is AH298 = -37.136±0.509 kcal/mol. Low-temperature heat capacities were determined by adiabatic calorimetry from 19.1 to 304.6 K. The derived standard entropy is S298 = 38.03±0.14 cal/mol?K. The heat capacity was measured over the range 348 to 1,198 K by differential scanning calorimetry. These experimentally determined data were combined with data from the litera¬ture to calculate the Gibbs energies of formation and equilibrium constants of form¬ation over the temperature range of the measurements. Standard enthalpies of forma¬tion are given as functions of temperature. The standard Gibbs energy of formation at 298.15 K is AGf298 = -600.36 kcal/mol.

Jan 1, 1984

By Oliver Q. Leone

The effect of oxygen content in the anode metal on titanium electrorefining characteristics was studied. Increasing quantities of oxygen in the anode resulted in increased anode scale formation, decreased anode and cathode current efficiencies, lower titanium recovery efficiencies, and higher oxygen content of the cathode products. The titanium electrorefining process performed best when the anodes did not contain more than 0.5 percent oxygen, although anode dissolution was recorded for alloys containing up to 25 percent oxygen. Back emf affords a useful index of an alloy to electrorefining.

Jan 1, 1965

By Alan G. Mayton

The Bureau of Mines conducted one of the most extensive studies on surface mine illumination to date, to assess the illumination needs of mobile surface mining machinery with respect to the visual tasks required of machinery operators. Field Investigations were performed at 22 surface mining operations, coal and metal-nonmetal, within several mining regions of the United States. Visibility and illumination were measured for 159 visual tasks performed by equipment operators on or near 57 surface mining machines, including draglines, shovels, blasthole drills, bulldozers, loaders, haul trucks, graders, scrapers, and several service-type vehicles.

Jan 1, 1987

By J. H. Soulé

The Copper King copper-gold-silver deposit was discovered about 1880. Various individuals and companies have been interested in the deposit and considerable work has been done, although production, if any, has been small. The deposit is located in the western part of Laramie County, Wyo., and is favorably situated with respect to rail and truck transportation and high-tension power facilities. Mild summers and cold winters characterize the climate. Precipitation averages between 16 and 17 inches annually, with considerable snowfall in the winter. Permanent streams are small and most available water in being stored for use by Cheyenne, Wyo. Range grasses comprise the bulk of the vegetation, with small trees and shrubs common in the most rugged areas.

Jan 1, 1955

By T. M. Garland

A nomographical approach is proposed as a fast, easy-to-use, and reason- ably accurate method for estimating expected discounted cash flow (DCF) rate of return and payout time for onshore development drilling and oil production. All costs pertaining to drilling, completing, and equipping development wells, annual expenses of operation, maintenance, and taxes incurred in producing properties, and crude oil prices were considered in developing the nomographs. This report briefly outlines the origin, derivation, and use of the nomographs.

Jan 1, 1973

By B. K. Cantrell, K. L. Rubow

"Quantifying exposure to diesel exhaust aerosol in an underground coal mine depends on the ability to measure this component of respirable mine aerosol separately from coal dust. Such measurement is complicated by the carbonaceous nature of both the diesel and coal dust particulate that make up the respirable aerosol. Hence, special sampling and analytical techniques must be used to distinguish between these two aerosol components.As part of a continuing study of diesel exhaust aerosol characteristics, the U.S. Bureau of Mines has applied size selective sampling together with gravimetric analysis to separate and measure respirable diesel exhaust and coal dust aerosol concentrations in diesel-equipped underground coal mines. This technique is based on the premise that the diesel portion of the aerosol is predominantly submicrometer and the mineral dust portion is mostly greater than 1 µm in size. In the study, chemical mass balance (CMB) modeling, based on the distribution of chemical elements in aerosol and aerosol source material samples, is used to referee the analysis of diesel exhaust and mineral dust aerosol concentrations from the size selective sampling results.Based on the results of the study, the Bureau, in cooperation with the University of Minnesota and the U.S. Mine Safety and Health Administration (MSHA), have developed a prototype personal diesel exhaust aerosol sampler for underground coal mines. The sampler has three stages: a preclassifier stage to select for respirable aerosol, an inertial impaction stage with an aerodynamic diameter(d) size cut at 0.8 µm to separate diesel aerosol from mineral dust and collect the mineral dust, and a final filtration stage to collect the diesel fraction of the sample. The sampler has been evaluated in both laboratory and field experiments conducted by the Bureau, MSHA, and the Generic Minerals Technology Center for Respirable Dust (GMTC-RD)."

Mar 1, 1992

By D. Caruso

The health and financial costs of cumulative injuries are plaguing the mining industry. Industry leaders are concentrating on reducing the risk of injury to their workers through design and redesign of work environments. While ergonomics is not a currently regulated field, many mines are realizing that the only way to tackle their most costly injuries, cumulative injuries, is to make the proactive choice to understand those injuries, their root causes and to make workplace changes to prevent them from occurring. Reduction of these injuries not only improves the health and morale of the workers but increases productivity and profit for the companies. Knowledge and reporting of ergonomic risk factors by employees and ergonomics committees is key to these changes and to the reduction of cumulative injuries. NIOSH is developing strong relationships with industry associations and equipment manufacturers to leverage their communication abilities to transfer knowledge to their customers and make a difference in the health and safety of U.S. miners. The benefits of a formalized approach to reducing these injuries along with examples will be presented.

By S. L. Weber, Y. H. Cheng, D. E. Banks, J. K. H. Ma

"The aggressive industrialization of America, the development of powered tools which generated massive amounts of respirable-sized dust particles, a latency period which may mask the relationship between exposure and development of disease, inadequate (or perhaps even careless) understanding of the relationship between dust exposure and disease, and respiratory protection which has later proven to be inadequate have resulted in a series of epidemics of silicosis which have caused the premature death of many workers.1-11 Emphasis on the regulatory control of dust levels in the workplace has greatly reduced the development of pneumoconiosis in the United States and in other developed as well as underdeveloped countries, yet the prevention of silicosis or coal workers' pneumoconiosis has not come close to being accomplished. Despite the public health perspective that pneumoconiosis arc totally preventable illnesses, there appears to be little evidence that this is the case.Cases of pneumoconiosis continue despite aggressive enforcement policies by regulatory agencies, attempts at dissemination of very readable materials aimed at workers and management 12.13 and respiratory dust exposure standards which are in place and appear, for the most part, protectivc.14- 16 It is more than frustrating for all parties associated with advocating workers' health to see reports of workers with aggressive silicosis. On another level, both the physician and the affected worker are helpless when a diagnosis of silicosis or coal workers' pneumoconiosis is made. Both realize that there is no proven way to affect the natural history of these progressive inflammatory and fibrotic processes. Neither is there any ""compassionate use"" therapy. What must be developed, at the very least, is a ""salvage therapy"" which has the potential to reverse, or at least dramatically lessen, the aggressive natural history of silicosis which develops over relatively short time periods. Because of the aggressive nature of silicosis (compared to coal workers' pneumoconiosis) attempting to develop a therapy for this illness should be a priority."

Nov 1, 1995

By Ramie H. Thompson

1.1 BACKGROUND In many underground coal mining operations the use of electromagnetic field equipment, particularly communication systems, not only increases the overall efficiency of the mining operation but can be directly linked with mine safety considerations. The use of electromagnetic field producing equipment in underground coal mining operations can only be expected to grow. Several new communication systems have already been proposed. In addition, high-frequency producing equipments for many diverse uses in mining operations are under study. The use of these equipment in underground mining operations is hampered by the possibility of their electromagnetic fields interacting with the electric blasting cap operations commonly carried out in the mines. Such interactions can have at least two results bearing directly on mine safety: o premature initiation of the cap, either in its normal shot location or during hookup or transportation; o dudding of the cap so that normal firing operations do not cause irritation; thereby leaving unexploded high explosives after normal firing. Since the consequences of a premature initiation could, particularly in coal mines operations, result in catastrophe involving human life, the overall approach to prediction of possible hazard must be, as far as possible, of a "worst case" nature. The general problem of predicting possible RF hazards for any electroexplosive device (EED) is best treated by reference to Appendix A of

Jan 9, 1983

By Charles L. Harness

Magnesia (MgO) has a variety of uses, and it has become increasingly important as a war material because of the imperative demand for refractories to line metallurgical furnaces, and because magnesia is used to make the in aircraft and other implements of warfare. Magnesia occurs as an integral part of nearly 60 minerals, but it is extracted commercially from only a .smaller number, of them. The present commercial sources are magnesite, brucite, dolomite, raw sea water, sea water bitterns, and well brines. Magnesia Raw Materials Magnesite magnesium, carbonate MgCO3, theoretically contains 47.8 percent MgO and 52.2 percent CO2. There are two varieties of magnesite, crystalline and cryptocrystalline (dense or amorphous). The latter type, though, not so plentiful as the former, is generally purer. It resembles unglazed write pottery in texture, whereas the crystalline variety is generally dark and granular, though the color may vary. The principal domestic deposits, of crystalline magnesite are near Chewelah, Stevens County, Wash. (which has supplied most of the magnesite mined in the United States), in the Gabbs Valley area of Nevada (near Luning); and in Llano County, Tex. Crypto-crystalline magnesite occurs principally in California. Magnesite occurrences have also been reported in several other States, including New Mexico, New York, New Jersey, Pennsylvania, Massachusetts, Vermont, and Maryland, but these deposits have not been developed commercially.

Jan 1, 1943

By R. E. Campbell

Uranium metal of improved purity was prepared by electrorefining commercial magnesium-reduced uranium in a molten sodium chloride-uranium trichloride electrolyte. The best operating conditions for the preparation of refined metal were established as follows: an electrolyte containing 8.7 to 13.3 weight-percent uranium; initial cathode current densities from 300 to 1,500 amp/sq ft; and a molten salt temperature of 860° C. Ingots produced from electrorefined uranium crystals prepared with these operating conditions were substantially free of metallic impurities. The only impurities in the refined and consolidated metal were present in low or undetectable amounts.

Jan 1, 1965

By G. R. Strimbeck

This is a report on experimental work on development of a gasification process operating at near atmospheric pressures and using finely pulverized coal entrained in oxygen and steam. The gasifier was designed by The Babcock and Wilcox Co. in cooperation with engineers of the Bureau of Mines Morgantown station. The test work discussed in this report covers the first 34 tests made in the pilot plant in which a strongly coking Sewickley-bed coal, ground to either 70 or 90 percent through a 200-mesh screen, was used.

Jan 1, 1954

By W. J. Crawford, P. M. Gruzensky

"Several experiments have been carried out in efforts to evaluate qualitatively a variety of electrolytes for refining bismuth. Most extensive work was done with the basic tartrate, hydrochloric acid, and hydrofluosilicic acid electrolytes. Deposits that are smooth and adherent can be obtained from these three electrolytes if low cathode current densities are employed. All three electrolytes were effective in purifying crude bismuth considerably, with additional purification indicated in each instance by a reelectrolysis step.With the basic tartrate electrolyte best results were obtained when the electrolyte was at 40° C. and contained at least 100 grams of bismuth per liter. An apparent disadvantage was depletion of bismuth from this electrolyte, causing the deposits to become spongy and nonadherent.The hydrochloric acid electrolyte had the greatest tendency to yield rough, dendritic deposits. Best deposits were obtained at cathode-current densities below 2 amperes per square decimeter. A small amount of glycerin helped to produce a smoother deposit, and adding sulfuric acid or methyl sulfuric acid retarded the deposition of impurities. Very good results were obtained in electrowinning bismuth from a bismuth trichloride-hydrochloric acid electrolyte.Smooth and adherent deposits were obtained from a hydrofluosilicic acid electrolyte, with very good refining as regards lead and silver impurities; however, higher reagent costs and slow decomposition of the electrolyte have discouraged its use.INTRODUCTIONMethods of recovering bismuth from ores and byproducts were underdeveloped for many years because of the limited uses for bismuth, the pharmaceutical industry being the chief consumer. In the past decade or so additional uses for bismuth, particularly in the metallurgical field, have brought about increased demand for the metal with the result that bismuth is being recovered from byproducts that were once discarded. In addition to such uses as low-melting alloys, solders, bearings, die setting, etc., some interest has been indicated in bismuth as a possible coolant for nuclear reactors. The advent of ductile bismuth and bismuth-alloy thermocouple wire has contributed greatly to temperature measurement, particularly in the below-zero range."

Jan 1, 1956

By Maria I. De Rosa

Combustible materials, when burned, produce toxic gases and smoke, which may vary dramatically from one material to another, with resultant different total toxicity and smoke obscuration levels. This U.S. Bureau of Mines report presents smoke property data acquired for a variety of mine combustibles and shows that there exists a correlation between the smoke properties, the relative toxicity, and the smoke obscuration levels of those combustibles tested. These correlations can be used to devise simple, standard tests for determining the toxic and smoke obscuration hazards of mine materials during fire.

Jan 1, 1989

By W. P. Diamond

Coalbeds exhibit a directional permeability, with the maximum permeability oriented parallel to the face cleat. Thus, the most efficient pattern of vertical degasification holes for a coalbed is dependent upon cleat orientation. Surface joints, infrared photolinears, and Ronchi grating photolinears were investigated as potential estimators of subsurface cleat orientation. Cleat orientations were measured in 18 mines, in the Pittsburgh coalbed in southwestern Pennsylvania and northern West Virginia to be used as a standard against which prediction techniques would be evaluated. Two cleat systems with a strong geographic segregation were measured in the study area: N 670 W -N 280 E (950 separation) for the north, and N 76° W -N 17° E (930 separation) for the south. Directional data obtained from the three techniques investigated yielded satisfactory regional predictions of cleat orientation. Analysis of surface joints was the only technique considered sufficiently reliable on a local basis. Prediction of cleat orientation is based on the pairing of the principal directional sets into all reasonable combinations of fundamental systems. The system or systems composed of the most dominant sets nearest to 90° separation are likely to be a reliable prediction of cleat orientation. The most dominant set of the system selected is likely to be the face cleat.

Jan 1, 1976

By Elizabeth G. Baglin

Research was conducted by the Bureau of Mines to determine the feasibility of using electrokinetic densification to dewater Bayer process red mud, magnetic black mud prepared by pressure digestion of red mud in the presence of ferrous sulfate, and magnetic black mud formed by simu-lated Bayer digestion of Jamaican bauxite with added ferrous sulfate. Tests showed that the solids content of presettled muds could be increased from 25 pct to approximately 40 to 48 pct by gravity draining followed by electrodewatering for approximately 48 h. Electrodewatering may not be practical because of increased reagent and processing costs and because the muds must be thoroughly washed prior to electrodewatering to remove dissolved ions and decrease mud conductivities.

Jan 1, 1988

By Carl Rampacek

Recent research by the Bureau of Mines has demonstrated that the segregation process has merit for treating oxidized and mixed oxide-sulfide copper ores. The process comprises heating the crushed ore with salt and coke or other carbonaceous materials at about 700° C. to produce fine flake copper, which then is recovered by conventional copper-flotation methods. Bench-scale laboratory tests of a number of oxidized and mixed copper ores assaying 0.78 to 5 percent Cu gave copper recoveries of 73 to 96 percent. The flotation concentrates assayed 21 to 76 percent Cu, depending on the ore being treated.

Jan 1, 1959

By Edmund S. Leaver

The Precious Metals Section is concerned primarily with ore-testing problems associated with precious metals and with the analysis and concentration of a large number of the strategic-mineral samples that have been included in the research program of the Bureau of Mines. During the fiscal year 1938-39, 30 projects were completed. The requests for this service are based upon the desire of the sponsor to obtain the best or most satisfactory method for maximum recovery of the minerals. In many instances it is a question of improving present milling practice, with due regard to utilization of present equipment. In others, the probable tonnage available maybe the deciding factor in the choice of a particular recovery method. Under all circumstances the results of tests axe prepared with the thought of aiding a competent metallurgist, familiar with local conditions, to formulate a practical flow sheet or to assist the mill operator to correct known losses. A microscopic examination for identification of the mineral constituents and their association in each ore is always a big help, in planning the tests and may indicate the reason for former troubles or assist with best procedure.

Jan 1, 1940

By Edmund S. Leaver

The Precious Metals Section is concerned primarily with ore-testing problems associated with precious metals and with the analysis and concentration of a large number of the strategic-mineral samples that have been included in the research program of the Bureau of Mines. During the fiscal year 1938-39, 30 projects were completed. The requests for this service are based upon the desire f the sponsor to obtain the best or most satisfactory method for maximum recovery of the minerals. In many instances it is a question of improving present milling practice, with due regard to utilization of present equipment. In others, the probable tonnage available maybe the deciding factor in the choice of a particular recovery method. Under all circumstances the results of tests axe prepared with the thought of aiding a competent metallurgist, familiar with local conditions, to formulate a practical flow sheet or to assist the mill operator to correct known losses. A microscopic examination for identification of the mineral constituents and their association in each ore is always a big help, in planning the tests and may indicate the reason for former troubles or assist with best procedure.

Jan 1, 1940

By Sidney Katell

An economic analysis of underground gasification of coal, based on experimental results obtained by the Bureau of Mines, indicates that a gas suitable for use in a power plant might be produced for approximately $.62 to $.77 per million British thermal units. This estimate does not include cost of land purchase. The gasification experiments were conducted in a 3-ft. seam of high volatile A bituminous coal. The major factors which can influence a change in operating costs are height of overburden, power costs, thermal efficiency, and the gasification air inlet pressure. The following equations show the relationship of these factors to operating costs:

Jan 1, 1961