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By W. A. Stickney, J. W. Town

Batch and continuous - circuit flotation , leaching , precipitation , and electrodeposition studies were made by the Bureau of Mines to determine optimum conditions for treatment of complex mercury - antimony sulfide and mercury- arsenic sulfide ores and concentrates . On the Red Devil ore sample over 95 percent of both the mercury and antimony sulfides were recovered in a flotation concentrate containing 35.6 percent mercury and 21.0 percent antimony . By selective flotation a mercury concentrate containing 71.0 percent mercury and 2.9 percent antimony was obtained with a mercury recovery of 90.4 percent . Leaching results show that , with 150 grams per liter of sodium sulfide and 50 grams per liter of sodium hydroxide , 95 to 99 percent of the mercury , antimony , and arsenic sulfides could be extracted from the concentrates treated . Sodium hydroxide reagent consumption was based on the sulfides generated in the dissolution of the sulfide minerals and on the method of metal recovery used . Selective leaching of the antimony and arsenic sulfides with potassium sulfide dissolved more than 95 percent of either of these two sulfides and 0.5 to 5 percent of the mercury sulfide present . Methods for recovering mercury and antimony from solution were electrodeposition of mercury followed by electrodeposition of antimony , aluminum precipitation of both mercury and antimony , or antimony precipitation of mercury followed by antimony electrodeposition . The method used in recovering the mercury depended on the mercury- antimony content of the solution being treated .Batch and continuous - circuit flotation , leaching , precipitation , and electrodeposition studies were made by the Bureau of Mines to determine optimum conditions for treatment of complex mercury - antimony sulfide and mercury- arsenic sulfide ores and concentrates . On the Red Devil ore sample over 95 percent of both the mercury and antimony sulfides were recovered in a flotation concentrate containing 35.6 percent mercury and 21.0 percent antimony . By selective flotation a mercury concentrate containing 71.0 percent mercury and 2.9 percent antimony was obtained with a mercury recovery of 90.4 percent . Leaching results show that , with 150 grams per liter of sodium sulfide and 50 grams per liter of sodium hydroxide , 95 to 99 percent of the mercury , antimony , and arsenic sulfides could be extracted from the concentrates treated . Sodium hydroxide reagent consumption was based on the sulfides generated in the dissolution of the sulfide minerals and on the method of metal recovery used . Selective leaching of the antimony and arsenic sulfides with potassium sulfide dissolved more than 95 percent of either of these two sulfides and 0.5 to 5 percent of the mercury sulfide present . Methods for recovering mercury and antimony from solution were electrodeposition of mercury followed by electrodeposition of antimony , aluminum precipitation of both mercury and antimony , or antimony precipitation of mercury followed by antimony electrodeposition . The method used in recovering the mercury depended on the mercury- antimony content of the solution being treated .

Jan 1, 1964

By N. P. Gallagher

The U.S. Bureau of Mines investigated a hydrothermal sulfidation (HTS) and chloride leaching procedure to recover lead and silver from plumbojarosite. The plumbojarosite, generated during pressure-oxidative leaching of zinc concentrate in a commercial operation, contained, in percent, 25.4 Pb, 18.8 Fe, 1.4 Zn, 29.5 sulfate (S042.), 3.2 elemental sulfur (SO), 13.4 total S, and 7.4 tr oz/st Ag. The HTS was conducted in an autoclave and converted the plumbojarosite into amorphous iron oxide and liberated the Pb and Ag as sulfides (S2) The best operating conditions were 50 g of plumbojarosite and 7 pct So (2.04 g So added) in 500 mL of 2.0-mol/L NH3 at 150° C for 1 h. The sulfidation product contained, in percent, 37 Pb, 28 Fe, 2 S042., 7 total S, and 11.2 tr oz/st Ag. Flotation of the sulfidation product was conducted at pH 3 with 15-pct pulp density and 2.4lb/st of isopropyl xanthate as collector. The flotation concentrate contained 43 pct Pb, 25 pct Fe, and 13 tr oz/st Ag. FeCl3 leaching of the sulfidation product in a resin kettle extracted 98 pct Pb and 97 pct Ag from the sulfidation product, and HCI-Oz leaching in a shaker glass bottle extracted 99 pct Pb and 98 pct Ag. Both leach residues met the Environmental Protection Agency's Toxicity Characteristic Leaching Procedure (EPA-TCLP) standards for nonhazardous wastes. The HTS and chloride leaching procedure is a potentially effective method for detoxification of plumbojarosite-bearing residue from the zinc pressure-leaching circuit.

Jan 1, 1989

By R. R. Schehl

The Bureau of Mines has developed a quantitative Analysis for pyrite in coal by X-ray diffraction that can be accomplished in little more than 1 hour. To minimize the sample analysis time, data processing has been completely computerized with pertinent output information displayed on a VR12 cathode-ray tube display. Use of this computerized system is not only advantageous during the experimental stages of the pyrite analysis project but would also be essential if the X-ray diffraction procedure is accepted as a standard method of analysis.

Jan 1, 1973

By Kenneth L. Rubow, Virgil A. Marple, Zhigun Zhang

"A theoretical technique has been developed and verified experimentally for determining the aerodynamic diameter of irregular shaped particles. The aerodynamic diameter of a particle is a very important parameter for determining where that particle deposits in the respiratory tract. Many instruments, such as impactors and cyclones, will determine the aerodynamic size distributions of aerosol particles but few analyze the particles individually. The theoretical approach of our technique is to solve, by use of high speed computers, the three-dimensional Navier-Stokes equations to obtain the flow field around an irregular shaped particle of any contour. The computer program will then determine the drag on the particle, and thus the aerodynamic diameter of the particle can be calculated. The experimental approach has been to pass the particles through a centrifuge and collect the particles upon a collection foil. The position of a particle on the foil is an indication of its aerodynamic diameter. These particles were then shadowed in two orthogonal directions and inspected under an scanning electron microscope (SEM). The top view of the particle in the SEM plus the views of the two orthogonal shadows allows one to determine the three-dimensional shape of the particle. Studies have been performed on silica, coal and talc particles with aerodynamic diameters in the 1 to 4 µm size range. The three-dimensional shape, as is determined from SEM analysis, was used in the theoretical computer program and the results compared. It was found that in most cases the agreement between the experimentally and theoretically determined aerodynamic diameters was within 5%. INTRODCJCTIONThe equivalent aerodynamic diameter (EAD) of a particle, defined as the diameter of a unit density sphere with the same falling speed as the particle in question, is an important size measurement of the particle. This is especially true when attempting to predict where particles may deposit in the respirator tract. Therefore, EAD is an important parameter when considering respiratory diseases caused by particles, such as coal workers pneumoconiosis (CWP).Many instruments will measure the EAD size distribution of the aerosol particles, but few analyze the particles individually. Impactors, cyclones and virtual impactors normally collect particles upon substrates or filters which are · then analyzed gravimetrically to determine the mass concentration of the particles in that size classification. The EAD of particles can be measured on an individual basis with centrifuges, inertial spectrometers and the TSI Aerodynamic Particle Sizer (APS). Centrifuges are most ideally applicable for studying individual particles as the particles are deposited, on long removable foils, at locations dependent upon their EAD."

Jan 1, 1990

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 Foster Fraas

Review of the literature on solid solutions discloses that the relation between composition and magnetic susceptibility is not linear . Recalculation using a transformation of composition values to parameter v values provides for a linear relation with the magnetic susceptibility to the 1/2 power . Application to minerals is illustrated by the olivine and enstentite series .

Jan 1, 1964

By J. M. Stuve

Calorimetric data for the dissolution of scandium sesquioxide and scandium trichloride in 4.360 molal hydrochloric acid were used to evaluate the standard heat of formation of ScCl3(c). The heat of reaction for Sc(c) + 1.5Cl2(g) = ScCl3(c) at 298.15° K was computed as -225,440 ±340 cal/mole.

Jan 1, 1965

By William K. Tolley

The U.S. Bureau of Mines (USBM) is currently investigating the electrochemistry of mineral flotation. A significant need in this area is greater reliability of sensors. The USBM is testing electrolytic methods to clean and condition redox-sensing electrodes to improve the reliability and extend the service life of these instruments in the harsh physical and chemical environment of mineral processing slurries. A novel method for removing scale from fouled electrodes has been developed that includes anodic polarization to 1.2 V versus the Ag/ AgC1 reference potential, followed by brief potentiodynamic conditioning. Laboratory results show that this technique removes calcarious deposits from gold sensing electrodes and returns the electrodes to useful service within approximately 10 min. Mechanical abrasion to remove the scale is thereby avoided.

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 M. F. Dunn

A handbook to provide a quick reference guide for selecting and using jet fans in a variety of conditions was prepared. The document is intended for use by front-line supervision, ventilation engineers, and mine planners. Included are discussions of jet fan characteristics, selection and use critieria, and do's and don't's for easier operation, safety, and performance. The handbook is based on research at three underground metal/nonmetal mines having cross-sectional areas of 900 to 2,000 ft2.

Jan 1, 1983

By P. Kovalchik

The Bureau of Labor Statistics (BLS) classifies hearing loss as a separate illness category. Hearing loss accounted for 11% of all illnesses in 2005 (U.S. Department of Labor Bureau of Labor Statistics, 2006a). According to occupational data for coal mining provided by the Mine Safety and Health Administration (MSHA) from 2000 to 2005, operators that exceeded 100% noise dosage were from only seven types of machines: auger miners, bulldozers, continuous mining machines, front end loaders, roof bolters, shuttle cars (electric) and trucks (Title 30 CFR Part 62, 2000-2005). Roof bolting machine operators rank second among all underground machine operators that exceed 100% noise dose. There are approximately 600 underground coal mines with 3,930 roof bolting machine operators (U.S. Department of Labor, Mine Safety and Health Administration, 2005; U.S. Department of Labor Bureau of Labor Statistics,

Jan 1, 2008

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 Oliver Bowles

"Rhodesian asbestos is of high quality and is much in demand by American consumers. Production in Rhodesia was first reported in 1909. The production for this and each succeeding year is shown in the following table:The serious curtailment in production for the years 1912 and 1913 was occasioned by transportation difficulties. In 1914 a railway was projected to Victoria and thereafter production increased greatly. Up to 1916 asbestos was obtained,from the Victoria district only, but thereafter the Bulwayo district became an important,producer with minor quantities from Gwelo.In the Bulawayo district the productive area is about 2 1/2 miles long, with Shebanie mine at the north-west end, the Nil Desperandum at the south end, and the Birthday claims between them."

Oct 1, 1920

By D. G. Kuehn

Mass spectrographic studies have been conducted on the positive ions and neutral species of glow discharges containing 1.0 pct S02 and 1.0 pct CO in helium. Measurements were conducted for gas pressures from 3.5 to 10.1 torr using both dc and 60-Hz ac excitation. The ion species that were observed included S+, SO+, SO+, 0+, O2+, C+, CO+, and CO2+ with lesser amounts of SO3+, (CO)2+, SCO+, and (SO?CO)+ or CS+2. Interpretation of the functional dependence of the various ionic and neutral species on pressure and applied power showed that CO reacted with the SO formed in the discharges to produce CO2 and sulfur. Deposition of elemental sulfur was observed in the plasma container.

Jan 1, 1973

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 Todd M. Ruff

Current methods of inspecting wire rope for broken wires or excessive wear include visual inspection, physical measurements of rope diameter, and electromagnetic nondestructive testing (NDT). Visual inspection and physical measurement arc the least comprehensive methods. Electromagnetic NDT enables a more thorough assessment of the condition of a wire rope, but the repeatability, accuracy, and objectivity of this method can be improved. One means of achieving this goal is to use a computer to analyze the test data and determine the condition of the wire rope, including the presence of broken wires and corrosion, and the amount of wear. An off-the-shelf data acquisition and analysis system was tested in a U.S. Bureau of Mines laboratory using a continuous loop of wire rope containing fabricated flaws. The test rope was run through a commercially available NDT instrument. The output of the instrument, normally connected to a paper strip chart recorder, was digitized and analyzed with a personal computer. These initial tests were successful in showing that the use of a computer can improve current methods of NDT waveform collection and analysis.

Jan 1, 2010

By W. P. Yant, C. E. Traubert

"INTRODUCTION Canister-type gas masks have become an essential part of the equipment of many industries, not only for use in emergencies, but also in performing normal operations of industrial processes and procedures, particularly where ventilation is not practically or economically feasible. They are also used widely for enhancing safety of operations which previous to the development of gas masks had been performed in harmful atmospheres.Since the inception of industrial gas masks the Bureau of Mines has been actively engaged in endeavoring to increase the efficiency and safety of these devices, and this bureau has become a source of advice to manufacturers in producing devices of good quality and to industry in the proper selection and use of these devices. In order to give first-hand information and keep current with the demands and needs of industry it is necessary to perform investi-gations from time to time. This report deals with tests of certain types of commercial gas-mask canisters for protection against mercury vapor.TYPES OF CANISTERS EXAMINEDThis investigation included tests of the following types of canisters:(a) Gas-mask canister filled with 725 c.c. of granular activated charcoal, 8 to 14 mesh, and of a quality used in gas masks which meet the Bureau of Mines approval requirements 4 for protection against organic vapors."

Oct 1, 1932

By W. W. Weller

Heat capacities of ferrous molybdate (FeMoO4) and ferrous tungstate (FeWO4) were measured over the temperature range 51° to 298.15° K. Ferrous tungstate has a lambda type heat capacity anomaly at 74° K. The 298.15° K entropies are FeMoO4) 30.9 cal/deg mole and FeW04) 31.5 cal/deg mole.

Jan 1, 1966

By Robert A. Jankowski

The Bureau of Mines has recently identified five major factors that contribute to high respirable dust levels on the six U.S. longwall faces having the most difficulty complying with Federal dust standards: (1) a poorly structured cutting sequence, (2) a poorly designed external water spray system, (3) marginal waterflow to the cutting drums, (4) minimal controls at the stage loader and crusher, and (5) the lack of effective controls for dust generated during support advance. The results of this survey illustrate the need to address all the major sources of longwall dust generation and the need for mine operators to implement a variety of control procedures to assure compliance. The Bureau of Mines will continue to assist mine operators in implementing improved dust controls and will work to identify and evaluate controls for dust generated during support advance.

Jan 1, 1983

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