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By A. W. Deurbrouck

The separations achieved by eight conventional cyclone washers have been evaluated to determine their performance when processing intermediate size coal of 28 mesh bottom size. The dense-medium cyclones provided efficient, sharp separations in treating feeds of up to 44 percent of near-gravity material at separating specific gravities ranging from 1.42 to 1,55 (one separation of a secondary feed was made at 1.63). Complete washability analyses are shown by sizes of the composite feed to these cyclones. The magnetite losses per ton of coal processed ranged from 0.6 to 2.0 pounds; however, of the eight plants reporting losses, seven indicated magnetite losses were 1.1 pounds or less per ton of coal processed.

Jan 1, 1972

By Carl F. Wingquist

In support of Bureau of Mines studies of thermal fragmentation of rock, the elastic moduli of four types of rock were measured at temperatures ranging from room temperature up to 1,500° F (1,089° K). The sonic method was employed to determine the resonant frequencies of the rock specimens and from these frequencies, the elastic moduli were calculated. Data for Young's modulus, shear modulus, and Poisson's ratio are given as a function of temperature for Dresser basalt, Reserve taconite, Jasper quartzite, and Charcoal granite. Young's modulus and the shear modulus decreased with increasing temperature up to about 1,200° F and then became relatively insensitive to temperatures from 1,200° to 1,500° F.

Jan 1, 1969

By E. A. Rowe, G. H. Keith, B. D. Jones

An evaluation of electrowon tungsten powder was made by comparing its characteristics with conventional hydrogen - reduced tungsten powder . Electrowon tungsten powder was investigated with respect to particle size and shape , apparent density , flow rate , compressibility , green strength , and sintering characteristics . In addition , its chemical purity , absolute density , and purification by melting were determined . Significant findings were higher flow rates and better compressibility than hydrogen - reduced tungsten powder . However , the large particle size peculiar to the electrowinning process effectively prevented conventional sintering to a high- density material . The possibility of producing high - density material , using a new technique of hot swaging sheathed sintered - tungsten compacts , was demonstrated by the achievement of densities of 92 percent of theoretical .

Jan 1, 1965

By Oliver Bowles

This paper is the fourth of the current series issued by the Bureau of Mines on lime- plant problems . It is hoped that the information presented in these reports will develop sufficient interest among lime- plant operators to prompt them to discuss with the Bureau their own experiences , for it is believed by such an interchange of ideas conclusions will be reached that will be of practical benefit to the entire industry . Much valuable information has been obtained from replies to the papers already issued , but a more general response is greatly desired . It is hoped that many operators will contribute additions to the information on transportation systems now at hand by answering the questions on the final page .

Mar 1, 1923

By G. G. Campbell

The Bureau of Mines initiated a field test of underground coal gasitication to investigate the technologic feasibility of gasifying a subbituminous coal. The test site is near the town of Hanna, Wyo., about 70 miles northwest of Laramie. Preliminary results of the experiment are described. The coal was ignited in the central well of a 16-well pattern. Both forward and reverse combustion techniques were attempted to prepare a path of sufficient permeability to permit the high air injection rat s necessary for gasification. Gasification between linked wellbores was sustained for periods as long as 3 months. Hydrogen-rich gas having a heating value of 100 to 150 Btu/scf was produced.

Jan 1, 1974

By Robert A. Miller

This computer program determines the price per ton of coal needed to obtain a profit of 12 percent discounted cash flow. From a predetermined equipment and manning list, the program calculates all costs and prints seven tables, Including the equipment and manning tables and the discount cash flow table. Forty-four of the input variables may be readily changed to study their effects upon the final price per ton of coal or upon individual cost items. The method is adaptable for any type of mining and with additions, for beneficiation processes. This program was written in Fortran IV for use on the IBM 11302 and with few modifications can be used on other computers.

Jan 1, 1971

By J. B. Littlefield

[Ata. meeting of the Subcommi ttce on Chemical _ et.lOds of Air Ant:..1ysis of-the American Public Health Ascociation in October 1937, the llse of the impinger for collectinG lcs.d fu.l1e wa:., discussed. The Bureau of Mnes de-cided to obtain infornw.tion on the efficiency of the lerge and midget im-pingers for this purpose y using the electric recipitator as a reference method. 'I'ests ~ ere made aJ,so to aScer ain the effici ency of the recently developed midget i;npi gerS..! for collac ing lead dust. For comparative pur-poses, samples collected by tte large impinger wore included.]

Jan 1, 1938

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 R. E. Head

[Surveys of the manganese situation conducted by the Geological Survey any other agencies have definitely established the, fact that the tonnage of high-grade manganese or in the United States is relatively small. It is therefore obvious that large-scale production of manganese is possible only through beneficiation of low-grade material. Deposits of low-grade manganese ore are being examined by engineers of the Mining Division of the Bureau of Mines to determine their size and possibilities as sources of manganese on a tonnage basis. The Metallurgical Division of the Bureau is developing and perfecting beneficiation processes with the objective of utilizing such low-grade ores. Microscopic study of these ores represents one phase of the research.]

Jan 1, 1941

By L. Cheng, M. S. Seehra, P. S. Raghoottama

The four major IR bands of a-quartz at 1080, 797, 693 and 488 cm-1 are studied at room temperature by FTIR-Photoacoustic Spectroscopy. Using Rosencwaig-Gersho theory, equations for the PAS signal q for the thermally thin and thermally thick cases are derived and it is shown how thin to thick transition occurs and leads to saturation as the sample mass is increased. For sample mass < 2 mg, q is proportional to sample mass thus defining the region for quantitative analysis. The dependence of q on the chopping frequency f is found to vary as q f-n with n ? 0.9 for quartz, in good agreement with the RG theory.

Jan 1, 1989

By W. D. Mcmillan

Preliminary examination of the north-central Kansas clay deposits was made by the junior author during March 1943. He was accompanied by Norman Plummer, ceramist of the State Geological Survey of Kansas. Three areas Nacre selected for further investigation. Detailed field investigation by the Bureau, consisting of hand auger drilling, trenching, anti. test pitting to obtain representative samples of the clays was carried on from April to June 1943. Field .work was under the direction of Edgar B. Butte and Richard L. Schumacher, former Bureau of Mines engineers. The samples taken were analyzed at the Bureau of Mines laboratory at Rolla, Mo. Factual data obtained from the field investigation and laboratory work are set forth in this report.

Jan 1, 1948

By Kenneth J. Miller

The Bureau of Mines two-stage coal-pyrite flotation process was modified to provide a more concentrated final clean coal slurry underflow which could be dewatered economically by filtration or centrifugation. This was accomplished by doing the first-stage coal flotation step in the conventional manner with a slurry of about 8 percent solids, but running the second-stage pyrite Flotation step with undiluted coal froth concentrate containing about 25 percent solids. The final clean coal underflow produced by the new technique contained between 26 and 30 percent solids; this pulp was sufficiently concentrated to be filtered industrially without further thickening. Sulfur removal was equal to that obtained using dilute second-stage pulp,

Jan 1, 1975

By K. K. Kelley, W. W. Weller

Heat capacity measurements of akermanite ( Ca,MgSiO ) , cordierite (Mg2A14 Sig018 ) , gehlenite ( Ca₂Al₂ SiO ) , and merwinite ( Ca ,MgSiO ) were conducted over the temperature range from 50 ° to 298.15 ° K. The entropies at 298.15 K ( expressed in cal / deg mole ) were evaluated as follows : Akermanite , 50.0 ± 0.5 ; cordierite , 97.3 ± 0.9 ; gehlenite , 47.4 ± 0.4 ; and merwinite , 60.5 ± 0.5 . All four compounds have positive entropies of formation from their constituent oxides at 298.15 ° K ; the values range from 4.6 cal /deg mole for akermanite to 10.1 cal / deg mole for cordierite .

Jan 1, 1963

By Clinton C. Knox

During the latter part of 1943, a magnetometric survey was conducted by the Geophysical Division of the Bureau of Mines at the Mahopac magnetite mine, Putnam County, N. Y., in an endeavor to locate a segment of the ore body that reports state was cut off by a fault. The Mahopac mine was abandoned about 1895 after producing nearly 1,000,000 tons of high-grade magnetite iron ore. The results of the investigation indicate the termination of the ore body by "pinching", or a displacement of such magnitude as to place any extension at a considerable distance from the original are body. This report describes the work done on the project and presents the data obtained.

Jan 1, 1948

By R. S. Dean

The principle of explosive crushing depends upon the fact that an expandable substance contained within the pores of a solid body will disrupt such a body upon expansion. Such expansion may be obtained by the detonation of an explosive or by the sudden release of pressure of a superheated liquid. That this principle of disruption may be applied to minerals rests on the fact that cracks, cleavage planes, and pores exist in all minerals to an extent hardly conceived possible heretofore. Crushing by this method takes advantage of forces applied from within the mineral rather than from forces applied from without. The application of a force from within would appear to be more effective.

Jan 1, 1932

By L. W. Brandt

Studies of liquid-vapor equilibria of gas mixtures at the Bureau of Mines Amarillo Helium Plant Laboratory require that the equilibrium cell be maintained uniformly at any desired temperature from approximately room temperature to -320° F. The temperature-control system must also tolerate a substantial heat input, in the form of warm gas flowing into the cell, without loss of control. Temperatures between the sublimation temperature of carbon dioxide (-109° F.) and the boiling point of liquid nitrogen (320° F.) are usually obtained by methods utilizing a hydrocarbon liquid bath cooled by liquid nitrogen.4/5/6/7/ Owing to the fire hazard attending such baths, a safer method of temperature control was desirable.

Jan 1, 1955

By E. G. King

Difficulty has been encountered in making thermodynamic calculations of metallurgical reactions involving interoxidic compounds of the ferroalloy elements because of the serious lack of most thermodynamic data for these substances. This Bureau of Mines report (the first of a planned series dealing with entropies of vanadates, tungstates, and molybdates) presents low-temperature heat-capacity data and entropy values at 298.15° K. for three crystalline sodium vanadates--metavanadate (NaV03), orthovanadate (Na3VO4), and pyro-vanadate (Na4V2O7). The results are combined with data for the constituent oxides and elements to obtain entropies of formation of the vanadates. Previous to this report only one vanadate had been studied Similarly, ammonium metavanadate.4/

Jan 1, 1961

By Owen W. Terry

During the summer of 1943 the Bureau of Mines conducted an investigation and program of churn drilling on the McIlhon and adjoining Pearson land in the Mineral Point district of Iowa County, Wis. Sixteen holes, aggregating 1,570 feet .of bore, were completed. The work was undertaken as part of a general investigation of the zinc-and lead-producing area of southwestern Wisconsin at a time when great effort was being made to increase the production of Metals important to the war program. The Bureau&apos;s drilling program supplemented a previous drilling pro-gram conducted by the Vinegar Hill Zinc Co., and demonstrated the presence of a strongly mineralized zone at relatively shallow depths.

Jan 1, 1948

By R. E. Meaker

Electrical conductivities and densities of molten fluoride systems were measured as functions of the melt temperature and composition. For any given mixture, the two properties change linearly with temperature. Three alkali metal fluorides were selected as solvents for melts of the type LiF-, NaF-, and KF-MFx, where M is a metal selected from the alkali metal or alkaline earth groups, or from the lanthanide or actinide series of elements, and x = 1-4. Heats of activation for conductance were calculated from the experimental data and varied from 2.3 to 9.2 kcal/mole at 1,000° C. Some relation between position in the phase diagram and the conductivity changes was suggested.

Jan 1, 1971

The generally disappointing results obtained in the present study, together with the high material costs involved, preclude any general recommendation for a continuation of the work. One recommendation arises, however, from some observations on the application of latex to spoil banks. It was found that dilute latex used on a slope of spoil bank material at an application rate of 400 lbs per acre (dry basis) stabilized the soil and made it much more resistant to washout by rainfall. It is recommended that a study be conducted to use latex for temporary stabilization and/or sealing of spoil banks before and during reclamation procedures, on coal slurry ponds and coal refuse piles.

Jan 1, 1972