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By V. Vallyathan, Xianglin Shi, N. S. Dalai

While Cr(VI) is a known carcinogen, the underlying biochemical mechanism is still not fully understood (1). In a pioneering study Jennette (2) utilized electron spin resonance (ESR) spectroscopy to demonstrate that a long-lived Cr(V) species is generated during the reduction of Cr(VI) by microsomes in the presence of NADPH. Later Wetterhahn and co-workers (3, 4) showed that incubation of chromate with isolated rat liver mitochondria causes the reduction of Cr(VI), as well as the formation of a Cr(V) species. Analogous Cr(V) species have also been detected in the reduction of Cr(VI) by other cellular systems such as Hanserulla polymorphared (5) and blood cells (6, 7). All these as well as other studies (8-12) have suggested that this Cr(V) species plays a significant role in the mechanism of Cr(VI) toxicity. Thus far, however, the chemical structure of this dominant Cr(V) species formed in cellular systems has not been identified, and this observation provided an impetus for the present investigation. Another reason for undertaking this study was that some recent reports (10-16) suggest that hydroxyl ('OH) radicals may also play an important role in the mechanism of Cr(VI) toxicity. In particular, it has been shown that OH radicals are formed in reactions between Cr(V) species and H2O2 (13-16), and that the radical yield depends on the chemical structure of the Cr(V) species (15). For example, while Cr(V)-diol complexes efficiently generate OH radicals, another Cr(V) species, the tetraperoxochromate (CrO3/8) ion, does not (15). Thus in the present study, we focused our attention on the following: (a) structural identification of the Cr(V) species generated in the reduction of Cr(VI) by subcellular as well as cellular systems, using microsomes, mitochondria, and Escherichia coli; (b) possible detection of OH radical in the same systems since there is no earlier report of chromium-mediated generation of 'OH radicals in a cellular system; (c) possible involvement of molecular oxygen in chromium-related OH radical generation since a recent report (17) indicated that Cr(VI) mutagenesis is strongly oxygen dependent; and (d) elucidation of the mechanism of OH radical formation in these systems.

Mar 1, 1992

By John E. Rourke, O&apos

A survey of existing and developing field permeability test methods was conducted in order to identify and specify capable methods to be used in feasibility investigations or performance monitoring for in situ leaching of ore deposits. Geologic settings of leachable deposits are discussed, as well as representative techniques used for the in situ leaching operation. Subsurface investigation techniques including drilling, core recovery, and down-hole inspection methods relevant to field permeability investigations are discussed. Field experience is examined and capable field permeability test methods are identified. Specifications for test borehole preparation, test performance. and methods of analysis are given. The test methods are comparatively rated in a matrix with respect to costs ease of use, and data effectiveness' for a broad range of conditions. Well Pump and Packer test methods receive high ratings. Recommendations are made for needed developments in field permeability test methods and a comprehensive bibliography is given.

Jan 1, 1977

By Fredrick L. Johnson

In 1986, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied 25,640 acres of the 29,680-acre Devil?s Garden Lava Bed, 21,040 acres of the 28,660-acre Squaw Ridge Lava Bed, and 9,100 acres of the 12,600-acre Four Craters Lava Bed Wilderness Study Areas (OR-D01-D02, OR-001-003, and OR-001-022, respectively) in order to evaluate their identified mineral resources. The study areas are located in Lake County, OR, about 50 air miles southeast of Bend. No mineral resources were identified in the three study areas. The areas are almost entirely underlain by recent lava flows. Cinder cones occur in each of the areas; however, the best cinder occurrences are in the Four Craters Lava Bed study area. Slab lava, of facing stone quality, is scattered throughout the Devil?s Garden Lava Bed study area, and to a lesser extent, in the Squaw Ridge Lava Bed study area.

Jan 1, 1987

By Sam Friedman

The Bureau of Mines conducted experiments using bench-scale apparatus to explore the effect of large changes in process variables on the yield and composition of the gases produced by passing 800° C steam through a fixed bed of Pittsburgh seam (hvab) coal. The total yield of combustible gases increased throughout the given range for the following variables: Superficial steam velocity increasing from 0.02 to 0.12 fps, pressure increasing from 1,000 to 6,000 psig, residence time increasing from 0 to 60 minutes, and temperature increasing from 800° to 900° C; however, a greater increase in the yield of hydrogen in comparison with the increase in yield of methane reduced the gross heating value of the gas to around 470 Btu per scf at conditions giving the maximum yield. Pressures of 1,000, 3,000, and 6,000 psig at 0.09 fps steam velocity, 800° C, and 60 minutes residence time, respectively, produced methane yields of 20, 24, and 22 percent, based on maf coal, with the gross heating value of the CO2-free gas decreasing from 552 to 520 and to 470 Btu per scf. Methane concentrations in the CO2-free gas were 26, 22, and 14 percent, respectively. Based on the gross heating value of the coal, the percentage of the heating value recovered in the gas was 60, 71, and 87 percent, respectively. The use of tungsten sulfide as a catalyst for converting carbon oxides and hydrogen into methane was explored briefly using both a sulfur-free gas rich in methane and a sulfur-bearing synthesis gas (3H2:1CO).

Jan 1, 1968

By William F. Hahn

The Bureau of Mines recognized the problems encountered in low seam mining illumination systems. It was determined that the best way of implementing an illumination system is to integrate the design during the design and fabrication of new machinery at the factory. The purpose of this program was to integrate an approved lighting system in a low seam battery powered scoop and evaluate its performance. This report documents the work performed on this program and the results obtained.

Jan 1, 1980

By A. T. Iannacchione, D. G. Puglio

The Bureau of Mines established geologic factors affecting the mining of the Lower Kittanning coalbed to aid in coalbed minability studies and examined the occurrence of "wants" (places where coal is missing) and types of unstable roof rock strata. Trends established from mapping, including prediction of areas of high methane emissions, were extrapolated to unmined areas. "Wants" in the coalbed are of two types: Erosional and depositional. Erosional features occur where north-south-trending sand-filled channels cut into the coalbed. Variations in depositional environments have caused the coalbed to "split" into several thinner units. Slickensides, commonly indicative of unstable roof, are adjacent to and on the underside of sandstone channels; they were caused by differential compaction and by soft sediment sliding along the contact between the sandstone and adjacent shale. The frequency of unstable roof also increases where the interval between the Middle and Lower Kittanning coalbed is less than 30 feet. The zones of weakness at the contacts above and below the Middle Kittanning coalbed are the controlling factors for unstable roof in these strata. Methane emissions from the coalbed are controlled primarily by depth, fracture permeability, and rank of coal. Local geologic factors are coalbed thickness, associated rock strata, structure, and proximity to outcrop.

Jan 1, 1979

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 R. Havens

During the course of the investigation of possible domestic sources of manganese, engineers of the Bureau of Mines examined and sampled two manganese mineral deposits in northeastern Utah. The Daggett Chief claims are situated in the northern part of Daggett County,5 miles southwest of Manila, Utah, and approximately 57 miles from Green-River, Wyo. Owners of the property are J.E. Harris Of Salt Lake City, Utah, Nels Palleson of Manila, Utah, and J. P. Larson. The manganese occurs in a vein 6 to 8 feet wide in a shale and sandstone formation. Two distinct occurrences Of manganese are present Within the vein, and samples of each were subjected to testing. Lot A, representing .probably the major portion of the Manganese; was composed of nodules and veinlets of manganese oxides in a semicompact; gray, shaly formation. Lot B represented a 15-inch vein of dense iron-manganese ore. .Most of the laboratory work at Salt Lake City, Utah, was done on these two samples; but preliminary testing also was carried out on a small sample, physically similar to lot A, submitted by the owners.

Jan 1, 1949

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 A. G. Starliper

The report covers studies by the Bureau of Mines on the removal of metallic values in two waste products from the Longhorn tin smelter at Texas City, Tex. One product was a slag that contained tin, tungsten, iron, tantalum, and columbium. The other product was a spent acid solution that contained tin, tungsten, iron, lead, copper, zinc, and silver and that came from presmelting treatment of impure tin concentrates. Molten slag was treated with sulfur or sulfur compounds and with coke, calcium carbide, or gaseous reductants to form tin sulfide that volatilized from the charge and to reduce tungsten along with iron and silicon to form a carbon-bearing metallic layer. The metallic layer was treated by an oxidizing alkali roast and then was water-leached to extract the tungsten. The waste acid was used in other experiments to dissolve an iron-tin- tungsten alloy (hardhead) obtained by direct reduction of the slag. An insoluble fraction containing tungsten, silver, silicon, columbium, and tantalum was removed, and copper was cemented on metallic iron, Tin was recovered by cementation on zinc plates, and lead was precipitated by adding sulfate ion. Iron was precipitated by increasing the pH which left a solution containing principally zinc. Slabs of hardhead were electrolyzed in an electrolyte consisting of waste acid to plate out groups of metals at different pH?s. The time did not permit thorough exploration of this method of treatment.

Jan 1, 1962

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 W. H. Herschel, E. W. Dean

"IntroductoryThe common practice of the petroleum industry is to measure viscosity by the use of instruments of the efflux or capillary tube type. The Saybolt universal viscosimeter has been tentatively adopted as a standard by the American Society for Testing Materials and is used extensively in the United States.Several instruments of foreign origin are also more or less familiar, such as the Redwood, the Engier, and the Baroey.Effina-type viscosimeters are well adapted to the ordinary needs of petroleum testing laberatories as they are simple and rugged in construction and away to manipulate, even in the hands of operators lacking scientific training. They have, however, certain limitations and for certain spacial types of work there are notable advantages incident to the use of the so-called torsion types of type of viacosimeter. The most satisfactory type of torsion viscosimeter now available in the market some to be that of MacMchael, which has been discussed in detail in a recent paper (Herschel, W. H., The MacMichael Torsional Viscosimeter. Jour. of Int. and Eng. Chem., vol. 12, 1920, pp. 282-286). The present paper indicates conditions under which this viscosimeter may be used to advantage in the petroleum laboratory, and outlines simple methods of operation and calibration."

Jan 1, 1921

By B. H. Eccleston, R. F. Kendall, D. E. Hirsch, Norman G. Foster

The mass spectra of 23 alkylthiophenes are presented , including 21 that have not been previously reported . Correlations between mass spectra and the structure of the thiophene homologs are discussed . Comparisons with , and corroboration of , earlier workers ' correlations and predictions are made . Several additional correlations are reported to enable the spectroscopist to identify the substituents on alkyl - substituted thiophenes , and the relationship of the mono - substituted and 2,5 - disubstituted alkylthiophenes is discussed in detail .

Jan 1, 1964

By W. J. Johnson

This report presents the Phase I progress in the development of a Radar Coal Thickness Sensor (RCTS) being conducted by Boeing Aerospace and Electronics for the Bureau of Mines. A method is developed for measuring both the dielectric constant and depth of the coal shale interface using a modified UHF network analyzer and antennas in proximity to the surface of the coal. Both bistatic and monostatic systems, are compared. The algorithm technique uses synthetic range gating for clutter rejection and full polarimetric scattering matrix techniques to extract the dielectric constant and depth to sub-wavelength accuracies. Tests were run both in the lab and in a coal mine to build an error budget and demonstrate a validation of the model. The development of a prototype radar suitable for coal mine robotics is specified.

Jan 1, 1990

By E. M. SEELEY, F. S. LOTT

Expansion in total capacity of the natural-gasoline industry.to produce light products continued in 1944 and 1945. The average rate of gain, however, was reduced to about 6 percent annually from over 9 percent in the preceding 4-year period. New facilities at cycle plants again accounted for most of the increase in productive capacity. Between January 1, 1944, and January 1, 1946, the number of cycle plants increased from 32 to 37 and their total capacity from 3,278 thousand gallons daily to 4,848 thousand (48 percent). Capacity of all other plants in the industry increased in the same period from 12,735 thousand gallons daily to 13,080 thousand, or only 3 percent. The capacity of the average plant increased to 28,600 gallons a day from 24,400 gallons on January 1, 1944, continuing the established trend. The average capacity of cycle plants increased to 131,000 gallons a day from 102,400 gallons, and the average capacity of all other natural-gasoline plants increased to 22,200 gallons a day from 20,400 gallons. Although the number of plants increased in only three States in the 2-year period (Texas, Okla- homa, and Arkansas), the total capacity of plants increased in eight States. A further decline of 29 reduced the total number of plants to 626 on January 1, 1946. Compared with 10 years earlier, gasoline plants were more numerous in only 4 States: Texas (48 more), New Mexico (7 more), Arkansas (2 more), and Louisiana (1 more). The largest declines, in order, were in Oklahoma, Illinois, Pennsylvania, West Virginia, and California. The number of plants with fractionating equipment for separating the liquefied gases from heavier fractions was 202 on January 1, 1946 and 182 2 years earlier. The principal changes in number and capacity of shut-down plants were an increase in Texas and a decrease in California. Shut-down natural-gaso- line plants are usually among the smallest units in their vicinity.

Apr 1, 1947

By K. P. V. Lei

The Bureau of Mines investigated molten salt electrorefining 'n helium atmosphere cells as a means for the production of ductile vanadium. 'Electrolytes composed of NaCl-VCl2, LiCl-NaCl-VCl2, BaCl2-KCl-NaCl-VCl2 KCl-LiCl-VCl2, and CaCl2-NaCl-VCl2 were tested. Two electrolytes, KCl-LiCl-VCl2 and CaCl2-NaCl-VC12, were selected for laboratory-scale production tests. A molten salt electrorefining process was developed for the production of ductile 99.6 percent vanadium from a commercial 90-percent grade. Using the CaCl2-NaCl-VC12 electrolyte, an 87-percent recovery of ductile vanadium was made; an 85-percent recovery was made with the KCl-LiCl-VCl2 electrolyte.

Jan 1, 1967

By E. P. Youngman

This paper is one of a series of digests of foreign mining legislation and court decisions that is being prepared in advance of a general report relative to the right of American citizens to explore for minerals and to own and operate mines" in various foreign countries. In the preparation of this interpretation of the laws of Norway, use has been made of William R. Orrmins' translations of various acts of the Norwegian Government, which were forwarded from the American consulate at Oslo^ and transmitted to the Bureau of Mines through the courtesy of the State Department. This digest is released subject to amplification and correction, if necessary, by the proper American foreignservice officers.

Nov 1, 1932

By Heine Kenworthy

In 1930 the Shenandoah-Dives Mining Co. near Silverton, Colo., put into operation a newly erected, 300-ton selective flotation plant to mill complex ores from its nearby mine. The operation was a steady producer and was enlarged to treat 600 to 800 tons a day. In 1942 the company opened and started milling an area in the mine containing semioxidized ore. The valuable mineral. Content of this ore was considerably higher than in the straight sulfide ore previously handled alone. The mixture of clean sulfide and semi-oxidized ore was difficult to treat; consequently tailing losses, especially with respect to lead, were high. A. few years later, in order to study the possibilities, of obtaining higher recoveries by a modification of the mill flow sheet, a 1,200-pound sample of mill feed, taken over a period of several days by the company, was submitted to the Mississippi Valley Experiment Station for testing. Although this sample proved to contain more than twice as much lead as the average yearly mill feed, the same problem of recovering the oxidized values were present.

Jan 1, 1948

By Ann Hubbs, Vincent Castranova, Jane Y. C. Ma, De-Hwa Chao, Joseph K. H. Ma

AN OVERVIEW OF THE ACTION OF TETRANDRINE ON SILICOSISBecause of the persistent presence of silica dust in the lungs silicosis is a progressive and irreversible disease. At present, there is no proven effective therapy for silicosis. Limited choices of therapeutic intervention with corticosteroids and other immunosuppressive regimens 1,2 have been accepted for some forms of pulmonary fibrosis. These treatments are only minimally effective, and the results provide little understanding of the disease state due to the lack of correlation between drug activity and the mechanism of fibrosis. Thus, continuing effort must be made in the search for effective antifibrotic agents, which may be used to provide a sequential analysis of the fibrotic process and to open the door for further research and clinical development. Tetrandrine is one of hundreds of drugs screened for antifibrotic activity by Chinese scientists. It has been used in China as a treatment for silicosis in open clinical trials3 and in laboratory animals. The action of tetrandrine on pulmonary fibrosis has been attributed to its ability to inhibit particle stimulation of alveolar macrophages, a key cell type central to the fibrotic process, to release oxygen radicals and inflammatory cytokines. Alveolar macrophages (AM) residing on the alveolar wall, are the predominant phagocytic cells of the lungs responsible for pulmonary defense against inhaled microorganisms and other particles and thus play an important role in maintaining the homeostasis of the lungs. 7 Ample evidence suggests that cells of the monocyte-macrophage series play an important role in the immunopathogenesis of pulmonary fibrosis. When upregulated by silica, alveolar macrophages generate reactive oxygen metabolites8·9 which can damage lung parenchyma and release fibrogenic growth factors and cytokines, 10,11 such as interleukin 1 (IL-1), which can induce fibroblast proliferation and collagen synthesis. The cytokine-mediated fibroblast proliferation and collagen synthesis are key steps in the development and progression of pulmonary fibrosis .11 Previous studies by our group have shown that tetrandrine exhibits strong binding affinity to AM and inhibits particle-stimulated respiratory burst activity (oxygen consumption, superoxide anion release, and hydrogen peroxide secretion) in these cells. 13 In addition, studies by Kang et al. 14 have reported that tetrandrine inhibits silica-induced release of fibrogenic factors such as IL-1 which are capable of inducing fibroblast proliferation and collagen synthesis. Reist et al. 15 further suggested that the antifibrotic action of tetrandrine may be mediated in part by the direct effect of this drug on the ability of fibroblasts to respond to proliferative agents. These results indicate that the mechanism of silicosis involves activation of AM and fibroblasts by silica, resulting in abnormal collagen production due to miscommunications between the cell types. Tetrandrine may interrupt this process by direct interaction with the lung cells.

Jan 1, 1998

By A. C. Richardson

During the past two and a half years the U. S. Bureau of Mines and the University of Alabama, with the cooperation of the different coal operators, have been making an extensive study of coal preparation in the State of Alabama. Considerable time has been devoted to the study of the washing characteristics of the Mary Lee bed and the various methods used in preparing from it a low-ash coal suitable for the manufacture of metallurgical coke. One of the phases of this problem is the utilization of middlings products from the washing plants. This paper gives the results of treating jig middlings on a coal-washing table at the Bureau of Mines laboratory at Tuscaloosa, Ala. The sample used was secured from the Sayreton washery Of the Republic Steel Corporation, Sayreton, Ala.

Jan 1, 1931