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By R. V. Ramani, S. Shankar

"Available literature on the effect of re-entrainment on overall airborne dust concentration in mine airways or the fundamental mechanisms of coal dust re-entrainment in mine atmosphere is scant (Shankar and Ramani, 1991 ). Therefore, as part of the Respirable Dust Center's ongoing research, the following three-part study was undertaken:• a study of the re-entrainment phenomena of anthracite and bituminous coal dust particles in a wind tunnel under the influence of varying air velocities;• a study of the same in the Lake Lynn Laboratory Mine of the USBM with both air flow and walking by personnel causing re-entrainment; and• the mathematical modeling and computer simulation of the re-entrainment phenomenon.In this paper, results from the re-entrainment studies in the wind tunnel and the Lake Lynn Laboratory mine are presented. Comparing the results from the two studies,it was observed that increasing the air velocity increased the rate of re-entrainment ( Shankar and Ramani, I 994a) and the rate of re-entrainment decreased with the time of exposure of the source dust to the flowing air. In addition, when the source dust was composed of particles of different sizes, the airborne dust concentrations due to re-entrainment were higher than when the source dust was composed of particles of the same size. The contribution of airborne dust concentration due to air flow was negligible compared to the contribution due to walking. IntroductionIn underground coal mines, dust is produced primarily during the process of mining and during such activities as pillar spall, loading, belt transfer and roof fall. The generated dust is entrained and then collects on surfaces through dispersion, diffusion and eventual deposition. Removal forces, such as flowing ventilation air or turbulence caused by walking and moving vehicles, can re-entrain the deposited dust (Hall, 1955). A portion of the re-entrained dust remains airborne and increases the concentration of airborne dust in mine airways.The presence of airborne coal dust in mine airways in large concentrations can be hazardous. Health effects include coal workers' pneumoconiosis (CWP) and silicosis, and it can be a nuisance affecting visibility. In addition, as is common during methane explosions, if the concentration of airborne coal dust becomes significant, there could be a coal-dust explosion (Singer, Cook and Grumer, 1972; Singer, Harris and Grumer, 1974; Edwards and Ford, 1988). Through concerned research efforts over the last decade, significantprogress has been made in reducing the airborne dust concentration in mine atmospheres. However, secondary sources, such as re-entrainment, have not been studied in-depth. It is important to understand the phenomenon of re-entrainment and its potential contribution to the airborne dust concentration in mine airways for further decreasing airborne dust hazards in mines."

Dec 1, 1996

By Robert D. Ewing

The computer program described in this user's guide provides for the static, three-dimensional, linear and nonlinear analysis of structural and geological systems by the finite element method. The guide describes the capabilities and general features of the program and shows how input is prepared. A number of recent advances in finite element theory and computer technology are incorporated in the program. Nonlinear material properties are provided for, including isotropic, anisotropic, and time-dependent material properties, gravity loading, simulation of a sequence of excavation or construction, and a slip or joint element. The finite elements include beam, rod, axisymmetric and plane quadrilateral, hexahedron, thick shell, and axisymmetric and plane joint. The program also has an automatic mesh generator to minimize user input preparation for continuum finite element meshes.

Jan 1, 1976

By D. Bienstock, R. C. Kurtzrock, E. R. Bauer, J. H. Field

To remove hydrocarbons and carbon monoxide in automotive exhaust by oxidation , a catalyst of 4.2 percent Uз Og , 1.7 percent Cr₂ 0 , and 1.7 percent CuO supported on 1 /8 - inch y- alumina spheres was tested in a reactor in place of the muffler of a 1 / 2 - ton truck . Tests were made with both nonleaded and leaded gasolines . With the engine at operating temperature , tests were made with the engine idling and with the vehicle cruising at 30 mph . Auxiliary air was added to maintain an oxygen concentration of 3 to 4 percent in the gas leaving the catalytic reactor . The vehicle was operated for 83 hours (about 60 percent of the time with the engine idling ) and 525 miles with nonleaded gasoline . Conversions of 98 percent of the hydrocarbons and 100 percent of the carbon monoxide were achieved with the engine idling and with 7,000 ppm carbon atoms and 4- percent carbon monoxide in the feed to the reactor . Hydrocarbon conversions of 75 percent were obtained at cruising speeds of 30 mph with a feed of 1,700 ppm carbon atoms ; the carbon monoxide concentration was less than 0.3 percent in the feed and was unchanged in passage through the reactor . Identical activity was obtained initially in switching to a gasoline containing 1.9 ml tetraethyl lead (TEL) per gallon . However, there was a gradual loss in activity thereafter . Conversions in tests with the engine idling about 50 percent of the time , had decreased by 23 percent for the hydrocarbons and by 25 percent for the carbon monoxide from their initial values after 122 hours and 1,300 miles of operation with leaded gasoline . The levels of radioactive materials in the exhaust of the reactor and the radiation in the vehicle were negligible .

Jan 1, 1963

By H. B. Hill

The Salt Flat field, formerly called the Joe Bruner field, is located northeast of the town of Luling in Caldwell County, Tex. This field, which is a fault structure, approximately parallels and is about 5 miles east of the Old Luling field. The proved area is approximately 1,280 acres, on which 332 producing wells (September, 1930) have been drilled. The majority of the wells are producing from the Edwards limestone at an average total depth of 2,700 feet. A few wells are producing from the Austin chalk or from other formations above the Edwards limestone. The Wilcox formation is exposed, and the fault trace in places is scarcely evident. The strike of the structure is approximately N. 20 to 45° The displacement of the fault is probably 200 to 500 feet. The discovery well was completed in the Austin chalk by the Lutex Oil Co. during April, 1928. In October, 1926, the Sun Oil Co. completed the discovery well in the Edwards pay. This well was an important discovery, as it indicated the potential oil possibilities of the Edwards limestone in echelon fault structures. The discovery led to the development of the third fault field in the Edwards limestone and opened up a large area for future prospecting.

Jan 1, 1931

By James R. Boyle

The value of Alabama's nonfuel mineral production in 1978 and 1979 was 8831.8 million and $336.4 million, respectively. In 1978, nearly all commodities registered an increase in production and value; unit value increased for all commodities, with the exception of native asphalt and sand and gravel. Alabama led the Nation in the production of crushed marble and was second in bauxite, third in masonry cement, kaolin, native asphalt, and oyster shell, and fourth in bentonite, dimension marble, fire clay, and scrap mica. Trend; and Developments.-The Alabama State Docks at the Port of Mobile handled more than 10 million tons of bulk material in fiscal year 1978; volume dropped slightly to 9.8 million tons in fiscal 1979. Bulk materials comprise the major activity at the facility, with iron ore and bauxite being two of the major materials handled. The movement of these ores is vital to the operation of many heavy industries in the State.

Jan 1, 1981

By Richard D. Miller

This Bureau of Mines publication contains analyses and related source data for 271 natural gas samples from 22 States collected during calendar year 1982. All samples were obtained and analyzed as part of Bureau of Mines investigations of the occurrences of helium in natural gases of countries with free market economies. This survey has been conducted since 1917. The analyses published herein were made by the mass spectrometer and chromatograph. The results of the investigation of the occurrences of helium are published annually to make the information available to the petroleum industry and the general public. Twenty-six publications have presented the results of 13,051 gas analyses vide prior to 1982. The first 3 bulletins (1-3)3 contain analyses and related source data on 5,218 gas samples collected from 1917 through 1960; these bulletins have been supplemented annually by information circulars (4-17, 19-24, 26) containing 7,833 analyses of samples collected since 1960.

Jan 1, 1983

By A. E. Sands

This report deals with a portion of the research and development work in the field of synthesis gas purification, carried out by the Bureau of Mines at its Morgantown, W, Va., Station in cooperation with West Virginia University. The Bureau's work in connection with gas purification has been performed with the objective of finding effective, low-cost, processes for removing impurities from synthesis gas to protect the catalyst used in the Fischer-Tropsch process for production of liquid fuels. Synthesis gas used for the production of other chemicals, such as ammonia, alcohols, and methane, requires equally rigorous purification. Although present-day practice in the manufactured-gas industry does not require such a high degree of purification, there is increasing interest in the complete removal of sulfur compounds from city gas. Although the gas-purification work at Morgantown deals with several impurities, major effort has been devoted to organic sulfur compounds in gas; this paper represents a progress report on some of the more important studies in connection with those compounds. Because this is a progress report on the Bureau's experimental work, no attempt has been made to cover the work of others on the subject; references to the literature have been restricted to those bearing directly on the work described.

Jan 1, 1950

By R. A. Beall, S. L. Ausmus

The development of a completely water - free expendable graphite mold material , useful for reactive metal castings , has been detailed . Mixing and curing variables have been evaluated both by physical testing of the material itself and by castings of titanium , zirconium , and hafnium . The blend of powdered graphite , cornstarch , dextrin , cereal binder , linseed oil , and Carbowax -4000 is a successful mix when mulled in a carbon dioxide atmosphere , and properly cured and fired . The primary advantage of this material is its adaptability to standard foundry techniques ; i . e . , core blowing and hand ramming . Temperatures in the curing and firing cycles do not exceed 960 ° C , and no vacuum firing is required .

Jan 1, 1964

By A. A. Sonnek

A simple, portable helium analyzer was developed primarily for field use. Its utility lies in making preliminary surveys before exact analyses are required. The analyzer is based upon chromatographic principles; that is, separation of gas mixtures resulting from variable retention times of the components with respect to a separation medium (column-packing material). It uses thermistors for sensing detectors, a dry battery as source of power, and a micro-ammeter for indicating helium concentration. The absolute accuracy of the instrument depends upon the recency and care with which the instrument is calibrated with a standard gas. The unknown gas should be analyzed immediately after calibration, and another calibration should be made before another unknown sample is analyzed. The instrument is simple to operate, requiring approximately 15 minutes, after calibration, to determine the helium content of a natural gas sample. Although developed primarily for helium determination, the analyzer possibly can be used for other analyses that can be performed at ambient temperatures.

Jan 1, 1965

By William J. Campbell

This study was a part of two programs: The first, to develop and evaluate high-temperature refractories; the second, to investigate reaction-rate kinetics and phase equilibria in the sinter step of the lime-soda process for the recovery of alumina. High-temperature X-ray diffractometer techniques are to be used extensively in both programs. This paper summarizes developments in the field of high-temperature X-ray diffractometers through 1959, evaluates various furnace designs, and describes briefly the X-ray diffraction facilities of the Federal Bureau of Mines. A more detailed description of the equipment and its calibration is planned in a future paper on thermal expansion and phase inversion of rare-earth oxides.

Jan 1, 1961

By W. M. Dressel

A simple, reliable field test for beryllium in rocks has been developed by the Rolla Metallurgy Research Center of the Federal Bureau of Minas. A small portion of the pulverized rock is fused with a sodium carbonate-sodium hydroxide flux in a wire loop. The fused mass is dissolved in water, a few drops of quinizarin solution are added, and the solution is viewed under ultraviolet light. A pink-to-orange fluorescence reveals the presence of beryllium in a sample containing as little as 0.013 percent beryllium (0.26 percent beryl). INTRODUCTION New and potential uses for beryllium make necessary a more intensive search for this metal, which is so similar to aluminum in its chemical reactions that it is not separated from aluminum in ordinary chemical analyses. The principal ore mineral of beryllium is beryl, a beryllium-aluminum silicate, which contains only 5 percent beryllium. This mineral is so similar to quartz in appearance that it is not always possible to distinguish one from the other in the field. While the distinction may be made easily with a petrographic microscope, few prospectors have access to such an instrument, and fewer still know how to use it.

Jan 1, 1960

By Robert H. Merrill

This report summerizes the various studies made to determine the size and support of roofs in the upper shale formation, White Pine Copper Mine, Michigan. These studies were a cooperative effort of the White Pine Copper Company and the Federal Bureau of Mines. Before this investigation, the upper shale formation had been found to contain about 30 to 40 percent of the total mineralization in the ore zones. Investigators estimated that this shale could be economically mined by room-and-pillar methods, provided that the roof would stand over spans of 25 to 32 feet. The problem remained to determine the number of bolts required to safely support these spans. Unbonded fractures in the roof structure of the deposit complicated the use of laboratory methods for determining bolted roof support. Therefore, a method was devised to determine the in-place support which would consider the unbonded fractures. In this method the roofs of 3 rooms with spans of 20, 28, and 36 feet were intentionally overbolted as the rooms were mined. Following stability tests that sometimes exceeded 6 months, the bolts were selectively removed and roof sag, roof strain, and changes in bolt loads were measured concurrently. The number of bolts required for support of these spans was computed from these data.

Jan 1, 1961

By Sidney Katell

Tonnage oxygen plants are or can be made available in sizes ranging from 150 to 1,000 tons per day. Capital requirements are estimated from $5,400 to $14,700 per daily ton, depending upon size of plant, cycle employed, and purity and discharge pressure of the product. Similarly, operating costs before return on investment will range from $4.80 to $10 per ton. INTRODUCTION Several processes4 5/ that can be used to convert coal to synthetic liquid fuels, synthetic pipeline gas, or hydrogen require high-purity oxygen as one of the basic raw materials. Depending on the and product and its specific use, the oxygen required will be of 95 or 99.5 percent purity. The quantity required, in turn, depends on the process for which the oxygen will be used and the size of the processing plant and will range from 150 to 4,000 tons per day.

Jan 1, 1960

By C. M. Paiencia

The Bureau of Mines studied the potential availability of primary antimony (Sb) from demonstrated resources in 21 mines and deposits in market economy countries (MEC's). Twelve of these properties were evaluated as producers and nine as non- producers. The 21 studied properties contain 499,600 mt Sb as demonstrated resources, of which 304,000 mt is recoverable as antimony metal; another 973,500 mt Sb is contained in inferred resources. Recoverable antimony from demonstrated U.S. deposits is only 10,700 mt, just 3.5 pct of the MEC total. Domestic production of primary antimony from operating mines has averaged only 561 mt/yr over the 10-yr period 1975-84. This represents just over 5 pct of total U.S. consumption of primary antimony, which averaged 11,081 mt/yr during the same period. The United States will thus continue to rely on imported ores andlor concentrates, antimony oxides, and metal to satisfy domestic industrial requirements. At production costs up to $1.15/lb Sb, 110,000 mt of refined antimony is potentially available from 10 of the 21 studied properties. At $2/lb, 294,000 mt Sb is available, and at $3/lb, the total rises to 304,000 mt Sb available from all evaluated producers of refined antimony.

Jan 1, 1986

By J. J. deBarbadillo

This Bureau of Mines report describes a process for recovering chromium and other metals from superalloy scrap. Laboratory-scale experiments were conducted to test a complex flowsheet utilizing a wide range of extractive metallurgical operations. The novel basis for the process is the fonnation of a sulfide matte in which chromium is concentrated in a discrete chromium sulfide phase. Mineral processing and hydrometallurgical procedures are used to separate chromium sulfide from the other matte constituents. The products of the process are a chromium-nickel alloy suitable for reuse in the superalloy industry, electrolytic nickel, electrolytic cobalt, and iron-molybdenum residue. Recovery of the principal elements contained in the scrap is chromium--93 percent, nickel--99 percent, cobalt--96 percent, and molybdenum--92 percent.

Jan 1, 1981

By D. A. Douglass

This report describes the tri-n-butyl phosphate extraction of cerium (IV) from a sulfate leach liquor prepared from a bastnaesite concentrate as well as from pure eerie nitrate solutions. The work was done on a laboratory scale using separatory funnels. Extraction from pure cerium solutions entailed no great difficulties; however, extraction from the bastnaesite solution proved more difficult, mainly because of the inhibiting effect of the sulfate ion. Despite this, procedures were developed for obtaining good single-state cerium extraction (95+ percent) and a high-purity product (99+ percent), although the maximization of both cannot be achieved simultaneously. This necessitates a compromise in any extraction scheme.

Jan 1, 1959

By N. E. Hanna

As part of a program for improving, the safety of permissible explosives, the Federal Bureau of Mines has undertaken an investigation to establish the ability of sodium chloride to reduce the incendivity of permissible explosives to firedamp atmospheres. A motivating influence for this investigation has been the comparatively extensive experience of British and other European investigators, who used sodium chloride as a component of their permitted explosives (1, 5, 6 7).5/ In the United States research and development work of this type has been less extensive, although sodium chloride has been added to permissible explosives as a cooling agent (9) for many years. The results of the first phase of this investigation were presented in a previous paper (8), which established that adding up to 10 percent sodium chloride to permissible explosives reduces the likelihood of ignition of firedamp in the gallery test; however, the results were somewhat inconsistent, and the conclusions were qualified. Accordingly, the investigation was continued with a study of the effect of added sodium chloride as a function of the quantity added and of the particle size of the salt.

Jan 1, 1960

By Robert F. Pettit

This paper on methods and costs of mining and milling iron ore at the Iron Mountain mine of Ozark Ore Co., St, Francois County, Mo., is one of a series of Bureau of Mines reports on methods, practices, and costs of mining and milling throughout the United States. The Iron Mountain operation is notable for its successful transition from open-pit to underground mining, for use underground of large earth-moving equipment, and for development of a multilevel room-and-pillar mining method. Milling methods also have undergone transitions - from hand sorting and log washing in the early days to gravity concentration. Milling ultimately may include flotation to recover additional iron from products now discarded as tailing,

Jan 1, 1957

By Charles L. Kimbell

In overview, 1988 appeared to be the best year for the world's mineral industry since 1980, although the all-important petroleum component suffered severely from low prices. With this notable exception, the traditional statistical measures of mineral industry performance, namely production, trade, and consumption, reflected growth in most elements of the world mineral industry from crude material extraction through the gamut of downstream processing. Moreover, the growth was reasonably well distributed geographically, with many countries sharing in the substantial upturn in activity. World crude mineral output value was estimated at over $1,272 billion in current dollars ($1,090 billion in constant 1983 dollars). The value added by the processing component of the mineral industry raised the total value of the industry's output to an estimated $3,057 billion in current dollars ($2,620 billion in constant 1983 dollars). Less easily assessed was the value of mineral commodities moving in 1988's international world trade, particularly because of the declines in world crude oil and refinery product prices. It remained to be seen if increased volume and value in nonfuel mineral and coal exports, coupled with an increase in the volume of oil exports, would be adequate to offset the drop in oil prices. Whether or not the value of world mineral commodity trade topped the 1987 level of over $498 billion, an increase in the volume of mineral commodity trade was almost assured. Similarly, although comprehensive statistics were not avail-able on consumption of all mineral commodities in all countries, available data on selected major commodities in selected major countries suggested that not only had output of most mineral commodities advanced, but so too had consumption levels for most commodities.

Jan 1, 1990

By McHenry Mosier

This paper describes come mechanical raid electrical signal systems in common use in Metal-mine shafts, together with several distinctive systems that indicate or control the origin of the signal. The latter systems remove the hazard of the movement of the cage from one level in response to signals from another. Previous publications of the Bureau of Mines have covered several meritorious installations One of the best signal systems for deep shafts is at the Homestake mine4/. A successful installation of an induction system in the Lake Superior mining region permits signaling as well as telephoning from cages at rest or in motion5/. El Potosi mine uses a variation of the three-wire electric system6/. A mine in Utah has developed a system of the double trolly-wire type, in which the cage attendant may signal from a moving cage7/. At present no system of the sine-shaft signaling employing radio is available.

Jan 1, 1939