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By L. H. Adami

This paper reports the results of solution calorimetry conducted to obtain the heats of formation of crystalline FeS04?6.952H20 and FeS04?1.008H20, from. which values were derived for the stoichiometric compounds FeS04?H20 and FeS04?H20. Also included are derived values of the free energies of formation and dehydration. This work was undertaken primarily to fill a need for data for pure, easily obtainable ferrous compounds that are suitable for use as calorimetric intermediates, The ferrous sulfate hydrates meet the essential requirements for this use.

Jan 1, 1963

By J. Croeni

The search for new alloys for application in the atomic energy field had prompted investigation of zirconium-rare earth metal alloys by the Federal Bureau of Mines. In this instance the zirconium-dysprosium system was investigated by melting point, thermal analysis, resistivity, X-ray and metallographic methods. Results indicate a single eutectic system with a peritectoid reaction occurring at 890° C. The eutectic isotherm extends from 30 to 95-percent dysprosium at 1,280° C. Eutectic composition is located at approximately 70 percent dysprosium. Solid solubility of dysprosium in both alpha and beta zirconium is extensive. The extent of solid solubility of zirconium in dysprosium has not been determined. Although zirconium rich alloys exhibit a significant increase in hardness, they can be cold worked extensively. These alloys also appear adaptable to solution heat treatment. Additional investigations concerning corrosion resistance and other mechanical properties are necessary for satisfactory evaluation of these alloys. The superior corrosion resistance of zirconium and the nuclear cross-section characteristics of the rare earth metals have stimulated alloy investigations using zirconium as a base metal. Alloys combining these characteristics present a possible substitute for hafnium as a control rod material. In this particular study dysprosium was chosen as the alloying element, and several series of alloys were used to establish the equilibrium diagram.

Jan 1, 1960

By A. R. Rule

This report describes preliminary studies by the Bureau of Mines to develop a procedure for extracting the fluorine from low-grade fluorspar ores in which the CaF2 particles are finely locked in the calcite matrix. A combination of flotation beneficiation and pyrohydrolysis is applied to recover and to liberate the fluorine. Flotation of a finely locked high-calcite fluorspar ore containing only 11.7 pct CaF2 recovered over 92 pct of the fluorspar at a grade of 51 to 52 pct CaF2. Pyrohydrolysis of the flotation concentrate liberated nearly 90 pct of the fluorine as aqueous HF. By this procedure over 80 pct of the fluorine contained in the original ore was extracted.

Jan 1, 1974

By Howard E. Parkinson

In 1969, new coal mine health and safety legislation was enacted in the United States. As a result of this legislation, the Department of Interior, Bureau of Mines has carried out communications research aimed at developing whole mine communications for increased safety and efficient operation. The research has advanced and many promising results are now being demonstrated to the mining industry. However, there remains a challenge to further improve wireless communications within the mine workings, and through the overburden above the workings. The objectives for future research and development will be discussed, together with the physical and operational constraints that new mine communication systems must face.

Jan 1, 1973

By Daryl E. Radcliffe

The Bureau of Mines, as part of an agreement with the Bear Coal Co., Somerset, Col o., evaluated the response of a coal mine roof to time lapse. Time lapse, the interval between exposure and support of the roof, was studied using both instrumentation and statistics. Instrumentation studies were designed to equate displacement and rates of displacement with areas of roof left unsupported from 15 minutes to more than 4 days. A statistical study was completed to compare roof fall occurrence with time lapse intervals encountered during normal room-and-pillar mining. Results from this investigation show time lapse, in the Bear mine, to he insignificant with respect to roof stability after installation of permanent support.

Jan 1, 1980

By H. E. Camargo

In an effort to decrease noise-induced hearing loss (NIHL) in coal preparation plant employees, the National Institute for Occupational Safety and Health (NIOSH) is conduct­ing research to identify and control dominant noise sources in vibrating screen (VS) machines. To this end, acoustic measurements of the noise radiated by a dewatering VS were conducted at the Pittsburgh Research Laboratory (PRL) using microphone phased-array technology. These measurements allowed for the identification of the screen as the dominant source in the 250 Hz 1/3-octave band. The sidewalls are the major contributors in the 315 and 400 Hz bands, whereas the eccentric mechanisms and the electric motor are the dominant sources in the 800 and 1,000 Hz bands, respectively.

Jan 1, 2009

By H. V. Makar

An aluminizing dross which is accumulating as a waste material in substantial quantities was tested for possible use as a steel deoxidizer. This material, consisting mainly of aluminum, silicon, and iron, was used to deoxidize laboratory-scale melts ranging from 7 to 100 pounds. Oxygen analysis showed that the aluminizing dross was effective in reducing oxygen levels in steel. A direct comparison with aluminum wire showed the dross material to be at least as effective. Under similar test conditions with 7-pound melts, 3 grams of aluminum reduced the oxygen concentration from 210 to 175 ppm, while 4 grams of aluminizing dross (equivalent to approximately 2 grams aluminum) reduced the oxygen concentration from 250 to 170 ppm. An additional 4 grams of aluminizing dross produced a final oxygen concentration of 140 ppm.

Jan 1, 1972

By Bruce D. Sartwell

A program was written which utilizes a remote teletype input to a time- sharing computer to plot charged particle or X-ray energy spectra which are stored in the memory of multichannel analyzers. The program, written in FORTRAN V, accepts the data printed out by the pulse height analyzer on paper tape and then, after reading these data tapes into the computer, plots on the teletype the desired energy spectra on a scale automatically adjusted for the maximum number occurring in the data. The program is flexible enough so that the researcher can subsequently expand or contract the vertical (intensity) or horizontal (energy) scales. With a slight modification, the program will accept data printouts from scalers or analog to digital converters. The program also includes a feature for integrating the energy peaks obtained by pulse height analysis.

Jan 1, 1970

By N. E. Hanna

An important goal in the development of coal mining explosives has been to improve their safety characteristics through suitable formulation. In the United States no systematic effort to establish factors influencing the incendivity to firedamp and to coal dust of explosives through research was made until the last decade. In consequence, American permissible explosives underwent only very slight modifications and many remained substantially the same as in the early years. As part of a long range program for increasing the safety of permissible explosives, the Bureau of Mines undertook to determine how the amounts and particle sizes of the principal constituents of these explosives affect their incendivity. It was found that an increase in the relative amount of sodium chloride and a decrease in its particle size significantly decreased the incendivity of our permissible explosives to firedamp (7-9).6 This is in agreement with findings reported by Dolan (4) for compositions of nitroglycerin and salt. One important result of the work at the Bruceton station has been the recent introduction of salt-formulated permissibles by several explosives manufacturers. This paper describes a statistically designed experiment for studying the effects of the particle size of ammonium nitrate and the type of carbonaceous materials used on the incendivity of permissible explosives. Interest in these particular effects goes back as far as the first formulations of coal mine explosives, around 1910 in the United States and even earlier in Great Britain and other countries. Although it is well established that fine

Jan 1, 1961

By C. L. Klingman

In extracting helium from natural gas at Bureau of Mines helium plants, a continuous analysis of the helium content of inlet and outlet gas streams is required to determine extraction efficiency. An analyzer, using established principles of gas chromatography to effect the analysis, has been developed by the Bureau of Mines to meet this need. It will record the helium content of inlet or discharge gases from helium-extraction plants every five minutes, continuously, without the attendance of an operator. A 25-inch column of activated charcoal is used as a partitioning agent; nitrogen is the carrier gas; and a hot-wire, thermal-conductivity cell is the detector. A 1.0 mv, strip chart indicates the unbalance of the detector cell, Sample size is 0.37 cc, and carrier gas flow rate is 75 cc, per minute. Significant improvements in helium extraction have been demonstrated by using the chromatograph in three helium-extraction plants.

Jan 1, 1961

By Fred C. Turin, Lisa J. Steiner, Kim M. Cornelius

Like many experienced workers, remote control continuous miner operators perform their everyday jobs making choices and decisions that they may not consciously think about. While performing tasks, they are continuously processing feedback and cues which guide them for the next move. Initial training teaches the operators the tasks necessary to operate the equipment and perform the job. However, with experience they are better able to deal with hazardous conditions and non routine situations. To better understand what potential cues and feedback help to guide the operators, a questionnaire was developed to learn what factors affect decisions. Operator responses address issues related to specific tasks, equipment operation, visibility, lighting, and communication issues. The information collected is useful to understand what cues experienced operators use to make task performance decisions. Results will be used to develop interventions and training for safe and effective operator performance.

By E. L. Litchfield

Spark ignition of combustible-gas mixtures is a relatively old subject of investigation and has been treated both experimentally and analytically by many people. Elements of static and current electricity are almost always present in mining and industrial operations, and the spark can be an extremely efficient source of ignition. Thus the practical interest of such problems as the "intrinsic safety" of electrical apparatus is obvious. Ignition and quenching phenomena are the primary laboratory representatives of combustion phenomena that are dynamically nonsteady, and such nonsteady phenomena playa considerable part both in industrial processes and in safety matters, although they are of less immediate practical interest. Considerable effort has been expended by the Federal Bureau of Mines in investigations of spark ignition.5 6 7 8/ Primarily, this work has established the significance of several of the parameters involved. Although the

Jan 1, 1959

By H. Kenworthy

The objective of this research was to develop methods and determine conditions under which metallic sulfides with lower boiling points than sphalerite may be removed from zinc sulfide concentrates by volatilization. A higher percentage of extraction of lead, cadmium, and germanium than is common in current practice was sought. The investigation, conducted by the Metallurgical Branch of the Minerals Technology Division, Region VI, showed that, under proper conditions, it is possible to remove over 90 percent of the lead, cadmium and germanium as an enriched sublimate. The uses of lead, and cadmium to a lesser extent, are well-known. Although germanium was discovered in 1886 by C. Winkler, commercial use has been achieved only in recent years. The amount consumed per manufacturer unit is so small that the price of germanium may still be quoted by the gram. The electronic industries have been the chief consumer of this semiconductor. Germanium is sold largely to the fabricator as a dioxide for reduction to metal and subsequent processing into wafers for use in diode and triode electronic tubes. Extensive research at Purdue University during World War II led to the first practical use of germanium.

Jan 1, 1952

By K. C. Dean

A semiquantitative test for the presence and identification of cesium and rubidium in rocks, clays, and mineral waters has been developed by the Bureau of Mines. The test can be used in the field, as a guide for the prospector, geologist, or mining engineer engaged in location or development [w]ork. It comprises two simple spot tests of a solution prepared from the [m]ineral sample. Phosphomolybdic acid, added to a drop of the test solution, [d]etects cesium, rubidium, and potassium in quantities as low as 60 parts per [m]illion. Silicomolybdic acid, added to a second drop of test solution, enables the operator to distinguish between cesium and/or rubidium and potassium. Test procedures, equipment requirements, and limitations of the method are described in this report. Cesium and rubidium were discovered in 1860 and 1861 by Bunsen and Kirchhoff with a spectroscope. The elements usually occur together, particularly in granite and granitic pegmatites. Rubidium does not occur as an essential constituent of any known mineral, yet it is found as a minor element in so many minerals that rubidium is 16th in abundance in the earth's crust. Cesium, which ranks as the 37th most abundant element, is the principal component of pollucite and a minor element in a wide variety of minerals.

Jan 1, 1960

By Larry R. Wilson

The development effort described herein was directed toward the design and development of a flexible communication system to provide two-way section communications between any telephone on an MCM-101 telephone FDM exchange and a miner provided with a uhf walkie-talkie transceiver. The system also provides normal communication between miners within a working section through the uhf coupler interface repeater.

Jan 1, 1976

By R. Carson Dalzell

The use of nuclear fission for chemical process heat offers the special advantage of high temperature, limited only by materials of construction. The process heat may be supplied economically at elevated pressures, since no compression of combustion air is required. For the initial effort in developing a high-temperature reactor, the indirect cycle, using helium as the heat-transfer medium, was chosen. The major problems are the design of high-temperature fuel elements, construction of an exchanger to transfer heat to process streams in the range of 2,500° F., and development of compressors capable of recycling helium at 1,000° F. and above. A conceptual design of a nuclear reactor to furnish process heat for coal gasification has been made. Spherical fuel elements utilizing a graphite structure, impregnated with uranium carbide fuel, were chosen, as spheres offer the possibility of easier loading and unloading of the reactor. Calculations of pressure drop and gas-pumping power for the system are included.

Jan 1, 1959

By Michael A. Trevits

During the time period from 1990-2007, there were 1601 reportable fires that occurred in the U.S. mining industry (an average of 89 fires per year). The leading causes of U.S. mine fires include flame cutting and welding operations, frictional heating and ignitions, electrical shorts, mobile equipment malfunctions, and spontaneous combustion. The National Institute for Occupational Safety and Health (NIOSH) is conducting a program of research addressing metal/nonmetal and coal mine fire prevention, detection, management and suppression. In the metal/nonmetal area, work was focused on technology transfer and training, and research to reduce the number of mobile equipment fires and their hazards. In the coal arena, research is underway to determine the root cause of cutting and welding-related fires and to evaluate the effects of ventilation schemes relative to the spontaneous combustion risk in longwall mines. Relative to fire management, research is ongoing on remote mine seal installation and remote mine fire suppression technologies. Finally, research is continuing to develop comprehensive and usable smoke management techniques and to develop mine fire growth models, propagation, and suppression. This paper presents a summary of some of the mine fire research and provides an overview of the next phase of the NIOSH mine fire research program.

Jan 1, 2010

By J. B. Gayle

This investigation was conducted by the Federal Bureau of Mines to compare the selectivities of diverse flotation reagents and also of flotation and float-sink methods of separation. Flotation tests, using sodium chloride, an alcohol-type frothing agent, and a kerosine-pine oil mixture as reagents, were made on seven coking-coal samples representing four different beds. The results indicated equivalent selectivities relative to sulfur rejection when entrapment effects were minimized by recleaning the various products. Selectivities relative to ash rejection were also equivalent for some coals; for others, the selectivities of the reagents tended to increase in the order sodium chloride, alcohol-type frother, and kerosine-pine oil. Float-sink tests on these same coals generally gave results indicating better selectivities than those obtained in flotation tests at comparable levels of recovery.

Jan 1, 1960

By F. W. Brown

In 1942 the Explosives Division investigated electrostatic hazards associated with the manufacture, storage, and use of explosives. A report was issued in 19454/ presenting the data on the spark sensitivities of explosives. In 1948, the apparatus was redesigned and rebuilt to make the routine testing of explosives safer and more convenient. The rebuilt apparatus is described in this re-issue of the former report. Included are details of construction and a list of parts. PRINCIPLES OF METHOD In normal procedures without special precautions, it is possible for static charges to be accumulated on individuals or on ungrounded equipment or structures.5/ Static charges may be produced in many ways, but they are most commonly produced by rubbing or successive contact and separation of unlike surfaces, at least one of which is usually an insulator.

Jan 1, 1953

By Martin H. Stanezyk

The Bureau of Mines investigated leaching of selected copper sulfide minerals and a composite of impure flotation concentrates at elevated temperatures and pressures with ammoniacal solutions. Copper 1 (tractions of 96 percent were obtained by leaching chalcopyrite at 75° C under oxidizing conditions for 60 minutes. An extraction of 99 percent of the copper contained in the composite concentrate was obtained by leaching the product for 90 minutes at 75° C. In tests of bornite, chalcocite, and covellite, 90 to 97 percent of the copper was extracted at 20° C provided an 8-hour reaction period was used. At 75° C essentially complete dissolution of the copper from these three minerals was accomplished in 60 minutes. Additions of ammonium sulfate to the leach solutions were required to obtain high-percentage extractions of the copper from bornite, chalcocite, and covellite. Although ammonium sulfate was not required when digesting chalcopyrite, copper extraction was enhanced and less free ammonia was required when ammonium sulfate was added to the leach pulps. The chemistry of leaching copper minerals was studied. It was C, termined that chalcocite altered to covellite as one step in the dissolution When leaching iron-bearing copper sulfides, hydrated iron oxide formed on the mineral surfaces, indicating that a diffusion process prevailed. No evidence of covellite was detected.

Jan 1, 1966