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By R. S. Dean

A general survey of the metallurgical work of the U. S. Bureau of Mines has been given in an article in the Missouri School of Mines Alumnus, and a somewhat more detailed review of the bureau work on lead and zinc will be found in the Mining Congress Journal. C. C. Furnas has contributed one general mathematical article. Dean, R. S. U. S. Bureau of Mines. 4, 1930, pp. 7-8. Program of Metallurgical Investigations of the Missouri School of Mines Alumnus, vol. 4, No. Investigations of the U. S. Bureau of Mines on the Milling and Smelting of Lead and Zinc. Min. Cong. Jour., vol. 16, 1930, p. 799, 808. Furnas, C. c. Evaluation of the Modified Bessel Function of Am. Mathematical Monthly, vol. 37, the First Kind and Zeroth Order. No. 6, 1930, pp. 282-287.

Apr 1, 1931

By A. D. Hahn

This report describes reconnaissance by the Bureau of Mines of titanium-bearing beach sands on Ship Island in the Gulf of Mexico off the south coast of Harrison County, Miss. The purpose was to determine the ilmenite, rutile, and associated heavy-mineral content of black-sand-bearing beach sands. The investigation was part of a survey of titanium resources of the United States. Ilmenite (FeTi03), an iron-titanium oxide, is the major titanium-bearing mineral consumed in the titanium pigment industry. Rutile (TiO2), titanium dioxide, is used mainly as a constituent in welding-rod coatings and in producing titanium metal. The major fieldwork was conducted during the first half of February 1961. Nine holes, totaling 220 feet of bore, from which 110 samples Her taken, were drilled at widely spaced intervals on the island.

Jan 1, 1962

By M. A. Lucas

The Bureau of Mines has developed a computerized mathematical model to predict the distribution of accessory elements throughout a metallurgical process. The model can be used to determine process conditions that effect better accessory element control consistent with continued high primary metal recovery. The model presented is specific for determining the bismuth distribution in lead smelting but can be adapted to most extractive metallurgical processes. Thermodynamic, kinetic, and process parameters form the base for the model. Its logic and structure are described in detail.

Jan 1, 1983

By S. D. Maksimovic

The use of vertical surface degasification boreholes with bleeder systems and the use of a timbered bleeder system to degasify gob areas were studied by the Bureau of Mines. This report describes three gob degasification studies conducted in the Pittsburgh coalbed. One study was conducted to determine the number of panels degasified with one large borehole. The study showed that the borehole provided degasification for three panels. Another study was conducted during the retreat of a 35-acre panel with a single-entry and a two-entry bleeder system and a large surface borehole. A major portion of methane emitted from the panel was carried away by the bore-hole, leaving the bleeder entries relatively free of methane. The last study was made to determine the effectiveness of a timbered bleeder system. The bleeder entries successfully degasified the gob area when enough entries were available and adequate pressure was available to force the air through roof falls.

Jan 1, 1980

By Robert P. Vinson, Kissell. Fred N., Edward D. Thimons

"The Bureau of Mines investigated the presence and extent of methane accumulations in mine roof cavities using a full-scale mine model. Methane was released at a constant rate into the roof of a cavity built onto a 700-ft wind tunnel. Two box-shaped roof cavities were used in the study: one had a volume of 114.7 cu ft; and the other had a volume of 57.3 cu ft. Methane concentration was measured at 28 sampling points in the cavities using 21 different combinations of gas emission rates and air velocities. Brattice hung in the cavity helped reduce methane concentrations without auxiliary ventilation. It was also found that the effective ventilation rate increased by a factor of 40 in the large cavity and by a factor of 20 in the small cavity when air velocity was increased from 100 to 600 fpm.INTRODUCTIONAny location in a coal mine where 5 pct or more of methane is present constitutes a potential site for an explosion and roof cavities are likely locations. Unfortunately, little is known about the buildup of methane in roof cavities. Some research has been done using scale models where no air flows past the cavity so that methane disperses only by diffusion (5) 4 a rare situation in mines.No known cavity-model investigations have been made that simulate air and methane flow conditions normally encountered underground. These Bureau of Mines studies were undertaken to determine the extent and manner of methane buildups in coal mine roof cavities with air velocities in the range normally found in coal mines and with various methane emission rates."

Jan 1, 1978

By B. J. Dalton

Several relationships between coexisting phases for analytical binary solutions near the critical point are given. These relationships were developed from a consideration of a (G u, P) surface at constant temperature and a (G u, T) surface at constant pressure, where G is the molal Gibbs free energy, u is the concentration of component 1 expressed as a mole fraction, G is the pressure, and T is the temperature. These formulas should facilitate the calculation of some of the quantities useful in making thermodynamic consistency checks on phase equilibria data about the critical point.

Jan 1, 1970

By Philip E. Sanker

The Bureau of Mines conducted small-scale batch and semicontinuous tests on the reduction of zinc sulfide with iron according to the reaction ZnS + Fe ? FeS + Zn to determine reaction kinetics in the temperature range 1,000° to 1,400° C and to investigate the potential use of a scrap iron reductant. Batch tests indicated that a temperature of at least 1,300° C with a 1:1 mole ratio of Fe to ZnS is needed for good zinc recovery. Semicontinuous tests were conducted, using four zinc concentrate samples, containing various percentages of copper, cadmium, and lead, which were reacted with iron and iron contaminated with iron oxide and tin in an externally heated graphite furnace. Analysis of the zinc metal and FeS matte reaction products showed cadmium to be entirely in the zinc metal, copper to be in the FeS matte, and lead to be about 60 pct in the zinc metal and 40 pct in the matte. Tin reported to the matte, and none was detected above the O.OS-pct level in the zinc. Sulfur dioxide was not detected in the offgas when up to 20 pct of the iron was replaced by Fe203.

Jan 1, 1976

By T. L. Joseph

The purpose of this article is to describe briefly the operation of a 6-ton blast furnace on a charge of bauxite, limestone, iron ore, and cast-iron turnings and to point out the bearing which smelting such a charge has upon the production of alumina cement. One object of the experiment, conducted by the Bureau of Mines in cooperation with the Aluminum Co. of America, was to determine whether tae so-called Pedersen process3 can be applied to the blast furnace. This process consists of smelting a charge of bauxite, iron ore, and. limestone, and results in to products. One is a slag containing about 50 per cent of A1203 and is intended for use in manufacturing aluminum, and the other is iron low in sulphur. Complete details of the test are published in other reports4. Blast-furnace slag is now recognized as a satisfactory and economical raw material for making Portland cement, Wm. A. Forbes5 has recently reported that in 1926 an important steel interest used well over 1 million tons of slag in producing about 24 million long, tons of cement. This is equivalent to about ½ ton of slag for each ton of cement. Alumina cement can be made direct in the blast furnace. Its physical character would have to be changed by grinding, but no change in its chemical composition would be necessary.

Jan 1, 1928

1. In 2001, a total of 7,131 sand and gravel mining operations reported employment statistics to the Mine Safety and Health Administration (MSHA). Sand and gravel mines comprised 48.8% of all mining operations, the largest percentage of all mining sectors. Sand and gravel mines are distributed throughout all 50 states. The median number of operator employees per sand and gravel mine was 3.0.

Jul 1, 2003

By M. L. Whisman

Radiotracer techniques were developed for stoichiometric studies of photochemical reactions associated with atmospheric smog formation. Stock blends of separate hydrocarbon and oxygenated compounds were prepared and calibrated. 14C-labeled reactants and products in reaction systems involving hydrocarbons and nitrogen oxides at the ppm level were analyzed for qualitative and quantitative data. Precision and accuracy of these methods developed by the Bureau were determined by replication and statistical treatment of data, and these methods are described.

Jan 1, 1969

By Jerry E. Olson

In 1986, at the request Of the Bureau of Land Management, the U.S. Bureau of Mines studied the central portion, encompassing 20,727 acres of the 32,261-acre Badlands Wilderness Study Area (OR-005-021) in order to evaluate its identified mineral resources. The study area is located in Crook and Deschutes Counties, OR, about 12 miles east from Bend. No mineral resources were identified. The area studied is underlain by Tertiary and Quaternary basalt flows which are largely covered by a veneer of sand and silt. No mines, prospects, or mineralized areas occur within or near the study area, but some sand and gravel has been removed from alluvial deposits at the east and west sides of the area. Slab lava of marketable grade and quantity was not found in the study area. None of the study area is of current interest for geothermal resources, but the eastern third of the wilderness study area is leased (1984) for oil and gas.

Jan 1, 1987

By Yael Miron

Coal mines that undergo self-heatings, and specifically mines that sustain both floor heave and self-heatings, would benefit from the use of sealants to minimize air ingress to susceptible areas. The U.S. Bureau of Mines(USBM) evaluated three sealant systems for this purpose, bentonite-water mixtures, silicate gel, and guar gum gel. The guar gum-based gel was the only sealant that possessed the desired properties of elasticity, ease of preparation, adaptability to the mine, and a long life. In addition, since the gel consists mostly of water, it could quench or cool nearby heatings. Optimal formulations were determined in laboratory tests, and then tested in the USBM Safety Research Coal Mine. Two formulations resulted in stable gels that lasted for at least 12 months in the mine. Semi continuous preparation of gel using an eductor was evaluated and appears feasible. Although guar gum gel is expensive, selective use to prevent heatings in specific areas would be cost-effective, both interms of productivity and enhanced mine safety.

Jan 1, 1995

By Robert L. Chufo

The U.S. Department of Energy Pittsburgh Research Center,1 has developed and field tested a spatial, spectral sensor for measuring the thickness of mineral deposits. Knowledge of the dielectric constant of the material is not necessary because the electrical properties of the media are determined automatically along with the thickness or distance measurement. The technology was developed to measure the thickness of coal remaining in the roof and floor of a mine or the thickness of a coal pillar remaining between two mining entries for the purpose of guiding a mining machine. However, field tests have shown the new technique is equally valuable for measuring the thickness of each layer in a multilayer manmade structure such as highway paving or building foundations and the thickness of geological deposits other than coal, such as, salt, granite and sandstone. The noncontacting electromagnetic technique uses spatial modulation created by moving a simple dipole sensor antenna in a direction along each axes to be measured while the complex reflection coefficient is measured at multiple frequencies over a two-to-one bandwidth. The antenna motion imparts spatial modulation to the data and enables frequency domain signal processing to solve the problem of media, target and antenna dispersion. The technique overcomes the problem of multipath reflections from nearby metal structures and avoids the use of radio frequency absorbing material. In its present form the system measures material thickness of zero to over 3 m to within ±2.5 cm accuracy. The system parameters are variable to suit the application but for most applications default values of 40 cm antenna motion with measurements made at 401 frequencies from 0.6 to 1.4 GHz at each of 32 antenna positions with a power level of 0 dBm or less are more than adequate to provide a satisfactory signal-to noise ratio. In the range of 0 to 10 m the system operates in the continuous wave mode and by simply turning off the transmitter for ranges beyond 10 m the problems of time domain processing are entirely avoided. The technique can be implemented with a vector network analyzer, a servo controlled L-band antenna positioner, an IEEE488 bus controller and a process computer. An electronics package designed and constructed to operate in the harsh mining environment and providing 1, 2 or 3 dimensional image presentation is being evaluated as a replacement for the network analyzer. Key words: Ground penetration radar, Spatial, Spectral

By Charles W. Huggins

DEVELOPMENT of the electron microscope has permitted man to examine many small objects that could not be resolved by the light micro-scope. Diffraction, spherical aberration, and chromatic aberration are the main factors that limit resolution to about two-tenths micron with the light microscope. No matter how perfectly a light microscope is constructed and operated, it cannot possibly resolve points separated by less than two-tenths micron. Rapid development following World War II has produced many electron microscopes capable of 20 A resolution. Fibrous inorganic minerals are well suited for electron microscopic study. Many micrographs of chrysotile have been published, but electron microscopic study of the amphiboles has been somewhat neglected. New techniques in sample preparation have simplified the study of fibrous material. Ultrasonic energy has been very helpful in sample dispersion. This publication contains a representative group of electron micrographs of natural inorganic fibers that have industrial value. These fibers commonly are referred to as the asbestiform minerals. The Bureau hopes that the knowledge gained through electron microscopy and other scientific study of the natural inorganic crystalline fibers eventually will lead to the production of synthetic fibers that will satisfy the requirements of industry.

Jan 1, 1959

By A. L. Engel

This report is a compilation of preliminary and, in some cases, more extensive concentration experiments by the Federal Bureau of Mines on low-and medium-grade fluorspar ores from three localities in Nevada and one in California. The work was done on samples obtained from Shoshone mine, Nye County, Valery mine, Pershing County, and the Broken Hills mine, Mineral County, all in Nevada, and Dirty Weather mine, Inyo County, Calif. These investigations were made to aid in the development of domestic fluorspar resources, in line with the Bureau's long-established program of conservation of mineral resources. The treatment methods employed in the experimental work described included simulated or "heavy-liquid" gravity concentration of coarse minerals and comparatively fine-grained minerals, and flotation concentration of finely-ground minerals. These methods were attempted in order to beneficiate the ores and produce concentrates which could be marketed readily, with as high a recovery rate as possible, while using simple treatment methods suitable for small-scale operation.

Jan 1, 1961

By J. Douglas Causey

In 1985, at the request of the Bureau of Land Management, the U.S. Bureau of Mines studied a portion of the 110,000 acre Massacre Rim Wilderness Study Area (CA-020-1013). The area studied, containing 23,260 acres, is located in northwest Washoe County, Nevada, about 25 miles west of Vya adjoining the Charles Sheldon National Wildlife Refuge. Basalt caps older tuffaceous sedimentary rocks in an area that contains no claims or prospects. No mineral resources were identified during this investigation.

Jan 1, 1987

By Benton L. Tibbetts

Comprehensive geophysical measurements were made in the Tertiary Channel gravel deposits of Badger Hill, Calif., with the refraction seismograph, gravimeter, and well logging equipment, to develop a three-dimensional physical model of the gold-bearing gravels. Tests were also made of the applicability of magnetometer and electrical resistivity techniques. Results of 14 seismic profiles revealed four distinct layers with velocities of 1,600 ft/sec for loose gravel, 5,900 ft/sec for compact gravel, 8,600 ft/sec for cemented, blue gravel, and 15,500 ft/sec for bedrock. The depth to bedrock along the middle of the channel varied from a minimum of 100 feet in the hydraulically mined pit area to a maximum of about 300 feet in the upper bench area immediately south of the pit. These geophysical methods revealed that 40 percent of the drill holes necessary to delineate the deposit could be eliminated, at a cost saving of at least 30 percent.

Jan 1, 1971

1. In 2003, a total of 4,357 stone mining operations reported employment to the Mine Safety and Health Administration (MSHA). The major industrial classifications in stone mining are dimension stone (used for construction purposes), crushed and broken stone (aggregates), cement, and lime. • Stone mines comprised 30.3% of all mining operations. • Mines producing crushed and broken stone (n = 3,412) comprised 78.3% of all stone mining operations.

Feb 1, 2005

By Manuel Gomez

The mean and the standard deviation were used to describe general sulfur and ash populations as well as specific populations of these variables from one coal seam. Both the mean and the standard deviation were incorporated in the exploration process to determine the number of drill cores necessary for seam evaluation and to guide the sequential drilling plan. Probability regions were computed to establish a basis for predicting probable ranges of average sulfur and ash concentrations that may be expected upon continued or future drilling. A computerized plot program was utilized to interpolate sulfur and ash concentrations between grid points. The plot program, which is essentially a moving average technique, permits a rapid evaluation of sulfur, sulfur forms, and ash spatial distributions as a drilling program progresses sequentially. This information, in the form of contour plots, can be made available to both the mining engineer and the fuel technologist in advance of mining to outline reserves, to improve selective mining, and to anticipate preparation facilities.

Jan 1, 1972

By Mary F. Koehler

Interoxidic compounds, such as vanadates, have not been studied extensively in the field of thermodynamics. This is a report of three vanadates of sodium--metavanadate, pyrovanadate, and orthovanadate. Vanadates of other metals will be considered in future reports. The heats of formation at 298.15° K. of the three sodium vanadates (both from the oxides and from the elements) were derived from the results of sodium hydroxide solution calorimetry. Free energies of formation were obtained by combining heat and entropy values. The results support the conclusion that the three sodium vanadates were stable with respect to all possible decompositions in which vanadium retains its pentavalency.

Jan 1, 1960