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Control shearer-generated airborne respirable dust on longwall mining sections. Approach Previous Bureau studies have shown that using high-pressure water can have a significant impact on the amount of airborne dust released into the face airflow while cleaning and controlling the airflow in the immediate cutting zone. The basic concept to improve the drum water spray system was to utilize high-pressure (1,200 psi) inward-facing drum sprays to improve the dust knockdown efficiency of the spray system and confine the dust to the face area. This system would minimize the exposure of the shearer operator through dust avoidance and decrease face dust levels by suppressing the amount of respirable dust that becomes airborne. System Design In-mine tests were designed to provide information that would permit evaluation of the operation with different spray orientations and water spray pressures. This was achieved by comparison with a conventional baseline wet-cutting system consisting of 26 low-pressure bit sprays, located on the hit blocks to provide pick-point flushing. Total drum water flow was 60 gpm and was maintained continuously throughout all tests. The high-pressure inward-facing drum water spray system consisted of sprays located in each bit block, oriented 15° and 30° toward the face. The inward-facing water spray system was operated at either 800 or 1,200 psi.

Jan 1, 1989

By Charles L. Kimbell

The final 26 tables of this chapter, tables 14-39, extend and expand the statistical series on production that was started in the 1963 edition of the "Area Reports: International" volume of the "Minerals Yearbook" and that was subsequently updated and expanded in the 1965 and 1967-88 editions. In this year's edition, for the first time, a column has been added to each of these tables providing a 5 year average for 1985-89, inclusive. This should provide a clearer picture more rapidly of the role of each major producer over the 5-year period. The listing order of major producers, however, continues to be, as in past years, in descending order of rank in the year of review, 1989. With the inclusion of silver and uranium oxide in the 1988 edition of this chapter, this group of tables now includes each of the crude minerals that ranked from 1st to 19th in 1983 in terms of value of their output (as well as four others of lesser rank). These 23 crude mineral commodities accounted for 93% of the estimated value of world crude mineral of world crude mineral production in 1983. In addition, world output of five key down-stream products-aluminum, steel, cement, nitrogen in ammonia, and refined oil are included because of their significance as products.

Jan 1, 1992

By Claude W. Sill

In the course of a series of investigations on vanadium deposits of the western United States, the Bureau of Mines collected many hundreds of samples for chemical analysis. As uranium is often associated with these vanadium minerals, they were also analyzed for uranium, which was pound to be absent in a large percentage of the samples. Since the usual methods for determining uranium are laborious and time-consuming it is very desirable to have some simple qualitative test that can be applied prior to a quantitative analysis to determine whether uranium is present or absent and thus save the time and expense of applying the quantitative analysis to the large proportion of samples containing no uranium. To be acceptable, the test should be specific for cranium, sensitive enough to detect small amounts of uranium, and. simple enough to make it worthwhile to apply. The available methods for detecting uranium lacked one or more of the desired characteristics. Eventually, however, a method was worked out that satisfied all the requirements. This method is probably more specific and sensitive than the usual qualitative methods for uranium, and its simplicity and speed of application make it ideal for testing samples prior to quantitative analysis.

Jan 1, 1945

By G. A. Brady

Laboratory tests were conducted to determine the technical feasibility of separating anthracite particles from a water-anthracite slurry by atomizing the water and removing the resulting mist in an air current. Products containing 21 percent or less moisture were obtained from slurries made with minus 60-mesh anthracite. Typical recoveries ranged between 67 and 79 percent of the feed when the slurries were atomized in air currents with velocities below 70 ft/min.

Jan 1, 1967

By E. Morrice

The Bureau of Mines investigated methods for beneficiating platinumgroup metal ores from the Stillwater Complex , Montana , as part of its program to increase the supply of critical and strategic minerals and metals from domestic resources . This report presents results of a 5- day continuous campaign employing a pilot flotation mill to recover sulfide concentrate containing platinum- palladium values from anorthositic ore . A mercaptobenzothiazole - sulfuric acid reagent suite was used . The pilot flotation mill was operated at an average feed rate of 106 lb/ hr of ore . A rougher concentrate containing 8.5 pct of the feed was prepared ; it assayed 1.1 oz /ton Pt and 3.5 oz / ton Pd . Recovery of platinum and palladium were 91 and 87 pct , respectively .

Jan 1, 1965

By B. W. Gandrud

The upper part of the Alabama deposits of crystalline graphite consists of an oxidized ore derived from the underlying unoxidized ore through prolonged Weathering. The degree of oxidation in different sections and at different depths within the bed is not uniform. The original ore is hard and blue-gray; the weathered product is soft and brown and is the only part that has been mined to any extent. Samples of both oxidized and unoxidized ores were obtained from two of the large graphite deposits of Clay County. Three additional samples of oxidized ore were obtained from different portions of a third property in the same region. In this report, ores 1 to 5 are of oxidized material and ores 6 and 7 of unoxidized.

Jan 1, 1934

By Edward F. Redente

Several research projects have been conducted in the western United States to determine the optimum soil replacement thickness for reconstruction of rangeland and cropland. However, the information gained from these studies tends to be site-specific and not broadly applicable. Moreover, the possible interaction between soil thickness and mechanical and fertilizer manipulation of the overburden has not been adequately studied. To meet these information needs, research was initiated at Trapper Mine in northwestern Colorado in 1980 to study vegetation response to soil thicknesses of 15,30,45, and 60 cm and five manipulations that included disking, ripping, and fertilizing. All crops were harvested at peak standing crop and then weighed in the laboratory. Wheat grain yields were highest when soil thickness was 45 cm and the soil and overburden were ripped. Alfalfa yields appeared to be highest when overburden was disked and fertilized and soil was replaced to a thickness of 60 cm. For range vegetation, standing crop biomass was highest when overburden was ripped and soil was replaced to 60 cm thick. However, optimum performance was obtained from the maximum number of species and life forms by disking overburden and replacing 15 cm of soil. The performance of most range plant species has improved over the three years of the study. When the results of this study are compared to the results of other soil thickness studies, we can conclude that selection of management practices should be influenced by local climate, local soil and overburden conditions, type of crop or vegetation to be grown, and specific management goals for that crop or vegetation.

Jan 1, 1984

By Edward E. Johnson

The U.S. economy boomed in 1965, completing its fifth consecutive year of expansion. Although the advance was somewhat irregular, previous records for production, sales, employment, and income were topped. During the first few months of 1965, as the economy recovered from the depressing effects of the automobile strikes of late 1964, increases were unusually large. The gains moderated in early spring, but were stimulated at midyear by sharply rising capital outlays, excise tax cuts, in? creased Social Security payments, and accelerated Viet-Nam defense expenditures. Gross national product (GNP) in cur-rent dollars rose $49.5 billion or 7.8 percent, to a total of S681.2 billion. In constant dollars (effects of price changes eliminated), GNP increased 5.9 percent, a rate considerably higher than the historical postwar annual average growth of 3.5 per-cent. Demand increased in most final markets and was especially strong for business fixed investment and consumption expenditures. With the exception of construction, most of the increases in GNP were real, since prices increased less than 2 percent.

Jan 1, 1966

By H. D. Jacobs

A process for recovering both iron and manganese from four manganiferous ores of the Cuyuna Range was evaluated. It comprised: (1) Low-temperature gaseous reduction to convert nonmagnetic iron minerals to magnetite and manganic minerals to manganous oxide, (2) acid leaching to extract manganese, and (3) magnetic separation to reclaim iron from the leach residue. Iron recoveries from the magnetic products ranged from 70 percent to 90 percent; manganese recoveries from leach filtrates ranged from 75 percent to 95 percent. Two ores, from the Hillcrest and South Alstead properties, yielded magnetic products considered adequate for use as blast furnace feed. Although good yields of manganese were attained on all ores, appreciable iron accompanied the manganese into solution. Previous work, however, has shown that this iron can be precipitated almost quantitatively under autoclave oxygen pressure with very little loss of manganese.

Jan 1, 1970

By Oliver Q. Leone

Electrorefining tests using titanium-nitrogen alloys as anode material showed that no significant quantity of nitrogen was transferred to the cathode deposit. The nitrogen of the anode remained in the scale, and the titanium-nitrogen alloy was anodically insoluble in the electrolyte when the nitrogen content was 11 weight-percent.

Jan 1, 1966

By Herbert R. Babitzke

As part of a project to develop refractory metal alloys suitable for high-temperature structural applications, the Bureau of Mines applied solid solution and precipitation-hardening techniques to columbium and tantalum alloys. Thirty-three alloys were evaluated to determine their formability, strength, and oxidation resistance. Three alloys had tensile strengths near 40,000 psi at 1,200° C: Cb-1N-5W-5V-10Hf (No.4), Cb-15Hf-5W-0.5B (No. 31), and Cb-15Hf-SW-IB (No. 32). Oxidation resistance of the high-strength alloys was good. Alloy4 gained only 34 mg/cm2 at 1,200° C, and 21 mg/cm2 at 1,000° C in 2 hours. Hot forming was done without any protection from oxidation.

Jan 1, 1968

By Joseph D. Davis

The term "fusain" was first adopted from the French by the American geologist J. J. Stevenson in 1911, according to Wheeler, (1),3 who applies it to that portion of coal resembling charcoal, which he treats as one of the four ingredients of banded bituminous coal. The term has since been adopted by American writers. The Germans use it with slightly different spelling - namely, fusit. It is the equivalent of "mother-of-coal" and "mineral charcoal" of the earlier British writers. The English word fusain is also applied to "a crayon of fine charcoal" and is derived from the Latin root fusus. OCCURRENCE OF FUSAIN IN COAL AND ITS RECOGNITION Fusain is fairly widely distributed in coals of all ranks in varying amounts. It is almost always present in very thin sheets between the bedding planes of the banded coal constituents and presents a jet-black silky appearance who n the coal is split away. As fusain has little cohesive power the coal splits readily along the planes where it occurs. Such fusain bands often attain appreciable thickness -- frequently 1/4 to 3/4 inch. -Beet (2) has reported a maximum thickness of 2 inches for fusain partings, and Sinnatt (3) has found it in the form of plates and lumps; one lump taken by him from the Peacock mine weighed 3-3/4 pounds. Bore (4) has found it in coal balls. Sinnatt (3) states that fusain occurs in two forms, "the first a hard compact variety occurring rather rarely, which can not be pulverized by pressure of the fingers the second type is the common substance" -- that is, a very friable, easily pulverized material. The writer has also found the two types of fusain in the same coal bed and has observed that the hard variety contained considerable calcium carbonate, which probably entered the material in situ by infiltration. Sinnatt further remarks that the layers of fusain (soft type) usually contain less moisture than the coal (or lose it more readily on exposure), and when exposed they quickly change to flocculent powder so that the fines of the coal as mined are likely to contain a major proportion of this substance.

Jan 1, 1929

By A. S. Peck

This report presents the results of a cooperative study between the Bureau of Mines and the University of Utah to define the mechanism involved in the adsorption of oleic acid and sodium oleate on fluorite, calcite, and barite, using an infrared spectrophotometer for identifying and measuring the adsorbed reagents and reaction products. Fluorite, calcite, and barite react with oleic acid and sodium oleate in a water system, forming chemisorbed and solution products. The chemisorbed species is a surface mineral cation-collector anion salt, Chemical analysis of solution resulting from the adsorption reaction indicates that the adsorption process causes displacement of mineral anions, namely, fluoride, carbon ate, and sulfate from the surface of these minerals.

Jan 1, 1963

By Philip C. Tully

This Bureau of Mines report contains experimentally determined vapor-liquid equilibria data for a helium-nitrogen-methane mixture with a nominal composition of 15, 60, and 25 mole-percent, respectively. Measurements of the equilibrium phase compositions were obtained by means of a windowed cell, in conjunction with an automated chromatograph and a special analyzer for low helium concentrations. The data presented include a comprehensive table and eight graphs depicting phase compositions, vaporization ratios, and correlations with a previous study of two helium-nitrogen-methane mixtures of different compositions.

Jan 1, 1976

By J. B. Gayle

Since the turn of this century, there has been increasing interest in the application of flotation processes to the beneficiation of finely divided minerals of various types, This is reflected by the large numbers of papers dealing with various aspects of this problem published annually both in this country and abroad. For the most part, such papers fall into one of three categories: 1. Those concerned with achieving, by various chemical and/or physical means, a set of conditions under which certain particles become potentially floatable while others do not. 2. Descriptive studies of plants and pilot plants effecting separations between such particles. 3. Studies of the effects of certain design and operating variables on the rates and efficiencies with which such separations can be effected.

Jan 1, 1959

By Jr. Karr

The Bureau of Mines studied the influence of carbonization method, temperature, and carrier gas on the composition of eight different low-temperature tars produced from a Colorado subbituminous coal. A fluidized bed was compared with an entrained bed, temperature was varied from 500° C to 650° C, and external heating using recycle gas as the carrier gas was compared with internal heating using oxygen-containing gas. The entrained bed yielded significantly more m-cresol and m-ethylphenol, indicating that thermodynamic equilibrium was more nearly approached in the system. Increasing the temperature greatly increased the yield of benzenes and naphthalenes, while paraffins, olefins, and total tar acids were reduced. Using oxygen in the carrier gas decreased the yield of low-boiling phenols and increased that of paraffins and olefins at 650° C.

Jan 1, 1966

By A. E. Raddatz

The Federal Bureau of Mines, as part of its goal to minimize undesirable environmental impacts associated with mineral processing, has investigated a soda-smelting technique for processing ilmenite into pig iron and a titanium slag that is suitable for a feed to a sulfate-process titania pigment plant. By this procedure, the generation of ferrous sulfate waste and its associated disposal problem is obviated. Molten titania slag was quenched, water leached, and filtered to yield a sodium titanate intermediate product containing about 70 wt-pct Ti02, 1 wt-pct Fe, and 20 wt-pct Na20. This intermediate product, high-soda titanate (HST), was mixed with H2S04, calcined, quenched, and water leached to produce a low-soda titanate (LST) product that contained only 2 wt-pct Na20. Both the HST and LST were evaluated as feed materials for preparing titania by the sulfate process. About 95 pct of the Ti02 was extracted from HST and LST by digestion in concentrated or 50-wt-pct-H2S204 solutions. About 95 pct of the solubilized Ti02 was subsequently recovered from the titanyl sulfate solutions by hydrolysis. Barren solutions from hydrolysis, containing about 26-wt-pct H2S04, were upgraded by vacuum-thermal evaporation or electrodialysis. The regenerated acid solutions were used to digest additional HST and LST.

Jan 1, 1979

By A. J. Forney

This report summarizes the findings of methods of treating caking coals in a fluid bed to destroy their caking properties. In batch tests it was found that several coals, including those with a free-swelling index greater than 8, could be decaed at temperatures from 400° to 425° C with a fluidizing gas composed of inert gas or steam containing 0.2 percent oxygen and a minimum residence LS,-;,' of 5 minutes. When treatment decreased the free-swelling index from about 8 to 1-1/2 or lower, the resulting treated coal was noncaking. In a continuous unit with continuous feed and discharge of coal, slightly more severe conditions were required to decake the coal. For 18- to 100-mesh coal a temperature of 430° to 440° C and an oxygen-to coal ratio of 0.4 cubic foot of oxygen per pound of coal feed was necessary. Finer mesh sizes required lower oxygen-to-coal ratios. In tests using air only as the fluidizing medium and treatment temperatures well below the softening range, the caking properties of 150- to 200-mesh coal were destroyed in 30 to 40 minutes of residence time at 200° C. Coarser sizes of 18 to 48, 48 to 100, and 100 to 150 mesh required longer residence time.

Jan 1, 1966

By Steven M. Shope

An essential element of the Bureau of Mines electromagnetic location and communication system for trapped miners is a quantitative knowledge of the surface and above-surface electromagnetic fields created by an underground transmitter. The field solutions given in this report use approximations in which the displacement currents are negligible for low frequencies. The earth is represented by a homogeneous half-space model in which a dipole source is immersed. The vertical magnetic field equipotential contours at and above the surface are graphically mapped. The volumes of the regions bounded by these contours are directly related to the geometrical zones of signal detectability. Knowledge of the detectability zones will enable the proper search strategies to be developed for airborne detection of trapped miners.

Jan 1, 1983

By Arne Landsberg

The Bureau of Mines measured the vapor pressure of FeC12 , FeBr2, FeI2, Sb, Bi, Cd, Mg, Pb, FeC13 , and VCl2 using the Knudsen-and torsion-effusion methods, and on FeC13 -NaC1 mixtures, Au2Cl6, and MgNi2 using only the Knudsen method. Apparent vapor pressures calculated from the experimental data vary with orifice size and method of determination. Reaction with residual oxygen in the instruments was noted to have an effect on the iron halide data. Vapor pressure curves plotted as log P versus 1/T (where P is pressure and T is absolute temperature) for one substance using several orifice sizes tended to converge at a single point when extrapolated beyond the experimental region. All of the data, except those of VC12, agree with previously published results. The importance of comparing effusion measurements with those obtained by other methods and the variations encountered with various orifice sizes are discussed.

Jan 1, 1977