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By K. J. Miller

A laboratory electrophoresis column was designed to separate pyrite from fine coal by utilizing an observed difference in the electrophoretic mobilities of the two materials in water. The apparatus worked well when tested with synthetic mixtures of coal and pyrite, but some modifications in design and procedure were necessary to provide a sharper separation. After these changes were made, the column was tested with a high-pyritic-sulfur raw coal sample. The column successfully fractionated the sample, removing not only the pyritic refuse, but a siliceous refuse as well. The invest ion demonstrated on a laboratory scale that pyrite and other impurities can be separated from fine coal by electrophoresis.

Jan 1, 1970

By R. Hogg

"The basic population balance models for agglomeration processes are reviewed and procedures are described for extending their applicability to systems with size-dependent rate constants and to the formation and growth of porous agglomerates from rigid, solid particles. Simplified procedures for the further extension of the models to include simultaneous agglomerate growth and breakage arc also described. IntroductionThe association of small particles into clusters or agglomerates is a significant factor in many facets of particle processing. Agglomeration processes are widely used to facilitate handling, storage and utilization of fine powders. Processes such as coagulation or flocculation are used to aid solid-fluid separation in dispersed particulate systems. Agglomeration also occurs as an accompaniment, often unwanted, to other particulate processing operations such as fine grinding, mixing and blending, transport and flow.Reliable agglomeration models are needed for improved understanding of the processes in general and of the complex role of numerous, interacting variables as well as for direct application to the design and control of industrial processes such as flocculation, granulation and pelletization. Ideally, the models should account for the primary forces responsible for agglomerate ·formation and growth, the effects of external forces on process dynamics, the development of agglomerate structure and its role in the process itself, and the effects of concurrent processes such as structure modification (e.g. compaction) and agglomerate breakage or degradation.In its most general form, the process of agglomeration involves taking discrete, independent particles, bringing them into contact with one another, promoting (or allowing) interparticle adhesion to occur and then causing structure rearrangement, usually under the action of external forces. The relative importance of these steps varies with the nature of the particulate system being agglomerated and with the kinds of agglomerates being produced. Coagulation or flocculation of particles dispersed in fluids is generally dominated by the contact and adhesion steps. In the granulation of powders, on the other hand, particles are already in contact so that structure rearrangement is the principal step."

Mar 1, 1992

By Jack E. Tress

The Bureau of Mines has been involved for several years in the development of processes for the recycling of solid wastes. As part of this program, a project was initiated to determine the feasibility of producing secondary pig iron from auto scrap. During the test period, 86,000 pounds of shredded auto scrap, along with petroleum coke and fluxing agents, was charged to a submerged-arc furnace of 1-ton nominal capacity. Eighty-eight thousand pounds of pig iron, with an average carbon content of 3.90 percent and an average copper content of 0.2 percent, was produced at an electrical consumption of 512 kW-hr per net ton. A cost estimate of the process showed that the pig, iron might be produced at a cost of $57 per ton.

Jan 1, 1973

By R. V. Ramani, R. Bhaskar

"The National Academy of Sciences (1) recognized the importance of studying the spatial and temporal characteristics of respirable coal mine dust atmospheres. In this paper, the progress to date of a research project on dust transportation and deposition in mine airways is presented. A mathematical model is proposed for studying the transport of dust. A source representative of dust generation in underground coal mining is defined. The influence and applicability of surface roughness, dispersivities, coagulation and reentrainment to vine dust flow arc examined. A convective-diffusion model is proposed for the transport and deposition of dust in mine airways. Using the model, the spatial and temporal characteristics can be evaluated in terms of dust concentrations in the mine atmospheres.INTRODUCTIONThe prediction of the behavior of fine particles Is Important in many fields of science and engi¬neering including physics, chemistry, mining, mineral processing, and atmospheric science. In mining from the health point of view, fine coal dust is associated with the appearance of pneumoconiosis in miners exposed to the dust. Also, in addition to being a nuisance factor obscuring visibility and general mobility of miners, it can lead to sudden catastrophic incidences of explosions. This paper outlines the progress to date of a research project on dust transportation and deposition in mine airways. A mathematical model is proposed for studying the transport of dust for the various mechanisms. The dust dispersion is defined in terms of a dispersion term determined from experimental data by Skubunov (23). Coagulation is considered as one of the mechanisms that can lead to changes in the particle size distribution. Reentrainment as a possible secondary source of dust was examined during model development but was not included in the final model."

Jan 1, 1988

By W. R. Reed, J. A. Organiscak

Surface mining operations use large off-road haul trucks extensively to move material at mining properties. Past research, using the United States Environmental Protection Agency’s (EPA) emissions factors for unpaved haul roads, has shown that haul trucks generate the majority of dust emissions from surface mining sites, accounting for approximately 78%-97% of total dust emissions. Observations of dust emissions from haul trucks show that if the dust emissions are uncontrolled, they can be a safety hazard by impairing the operator’s visibility. This increases the probability for haul truck accidents (See photos above). However, the greatest long-term health hazard of dust generated from hauling operations is due to inhalation of the respirable dust [median diameter <4 micrometers (µm)] and tho­racic dust, which is equivalent to the EPA’s definition of PM10 [particulate matter with a median diameter <10 µm]. Exposure to respirable dust has long been considered a health hazard at surface mining operations, especially if silica dust is present. There are two legislative acts that regulate the air quality for mining operations: the Federal Coal Mine Health and Safety Act of 1969 and the Clean Air Act of 1970. The Federal Coal Mine Health and Safety Act of 1969 established the limits for dust in the work place for health and safety pur­poses. The Clean Air Act of 1970 regulates air emissions from facilities from an envi­ronmental perspective.

By Charles K. Rose

The Cebolla Creek titaniferous iron deposits near Powderhorn in southern Gunnison County, Colo., were examined by the Federal Bureau of Mines as part of an overall program to investigate the Nation&apos;s titanium and iron resources. The deposits occur around the periphery of the Iron Hill stock, which underlies an area of about 12 square miles. Concentrations of magnetite, ilmenite, and perovskite arc localized along fractures in the pyroxenite stock. Mineralogical studies of composite surface samples collected in 1956 showed that most of the iron is present in ilmenite-bearing magnetite. Perovskite is the chief titanium mineral in the magnetite-rich and augite-rich types, and sphene is the principal titanium mineral in the placer material. The mica-rich rock contains approximately equal amounts of perovskite, ilmenite, and sphene.

Jan 1, 1960

By Victor E. Kral

The Modarelli iron deposit , formerly known as the Requa iron deposit , is 44 miles by road south of Palisade , Nev . , on the Southern Pacific and Western Pacific Railroads . Construction of 10 miles of new road, which is necessary in case the property is exploited , will reduce this distance to about 28 miles . The deposit was discovered in 1905 , and patent was obtained in 1907 . The present owners obtained title to the property in recent years by paying the delinquent taxes . There has been no production . The ore deposit is a replacement of a Tertiary volcanic believed to be a rhyolite . Except for evidence of slight shearing , the deposit has no apparent structure . Hematite is the principal ore mineral ; it is fine-grained and is associated with very fine-grained apatite and unidentified minerals assumed to be alteration products of residual rhyolite minerals .

Feb 1, 1947

By Christopher Van Dyke, Edward L. Petsonk, Knox Van Dyke, Vincent Castranova, Ji-Hee Kang, William Pailes

"INTRODUCTIONPlatelet-activating factor (P AF) has been shown to mediate a broad range of biologic activities (1). Chemical analysis has shown that PAF is a glycerophospholipid with a choline polar head group, an ester-linked acyl chain at the second carbon of the glycerol backbone, and an ether linkage at the first carbon. The alkyl group attached to the first carbon can exist in a variety of chain lengths, with the C16 and C18 forms predominant in humans. The structure of P AF has been identified as 1-0-alkyl-2-acetyl-sn-glycerol-3-phosphorylcholine (2,3).PAF can be released from a variety of cell types, such as basophils, neutrophils, and alveolar macrophages ( 4-6). Stimuli for the release of P AF include calcium ionophore, phorbol esters, chemotactic agents, and zymosan. In addition, endotoxin has been shown to be a potent stimulant of P AF release from alveolar macrophages (7).P AF has been shown to have a number of pulmonary effects. It has been associated with asthma since it can cause contraction of pulmonary tissue (8) and leukotriene secretion from leukocytes (9) and induce airway constriction when inhaled by humans (10). In addition, PAF is a potent chemoattractant and can cause migration ofneutrophils into the airspaces of the lungs (11,12). Endotoxin is a lipopolysaccharide-protein complex derived from the cell walls of gram-negative bacteria. I.PS is the lipopolysaccharide portion of endotoxin. LPS contains four covalently joined subunits: lipid A, 3-deoxyoctonate, a core polysaccharide moiety, and an 0-specific antigenic polysaccharide side chain. Rough LPS contains no 0-antigen side chain. The liP.id A portion of LPS has been associated with most of the biolQgic effects of endotoxin (13). This lipid A subunit consists of a D-glucosamine disaccharide backbone substituted with four fatty acid side chains. Endotoxin is found in a wide variety of occupational settings associated with organic dusts derived from plants or animals, such as cotton, cereal grains, silage, rice, and poultry (14-18). In addition, airborne endotoxin has been found in sewage treatment plants, composting plants, offices with contaminated humidifiers, and showers or saunas (19-22)."

Jan 1, 1990

By G. W. Birge

Carbonizing properties of the principal coalbeds of Elk, Clarion, Jefferson, Clearfield, and Centre Counties, Pa,, are described in this Bureau of Mines report, Twenty-six samples, representing the Upper Freeport, Lower Freeport, Upper Kittanning, Middle Kittanning, Lower Kittanning, and Brookville beds, were carbonized by the Bureau of Mines--American Gas Association (BM-AM) method, and yields of products and physical properties of cokes were determined. Expansion or contraction of the majority of the samples was measured in the Bureau of Mines sole-heated oven. Chemical analyses, agglutinating values, and free-swelling indexes are given for all samples. In this area the coals generally are characterized by high sulfur and moderately high ash content, and their suitability for metallurgical use would depend largely upon satisfactory cleaning. The samples from Elk, Clarion, and Jefferson Counties were high-volatile A bituminous In rank, whereas, most samples from Clearfield County and all those from Centre County were of medium-volatile rank. Coals from Clarion County had dry, mineral- matter-free fixed-carbon contents ranging from 56.5 to 60.3 percent and were weakly coking. With the exception of two samples which contained excessive ash, the medium-volatile coals of Clearfield and Centre Counties were strongly coking and, as indicated by sole-oven expansion results, would require blending with lower rank coal to avoid oven damage.

Jan 1, 1963

By Kenneth J. Miller

Laboratory batch flotation tests were conducted to determine the viability of the Bureau of Mines coal-pyrite flotation process in desulfurizing various coals from the midwestern coalfields. Nine coals obtained from western Kentucky and Illinois were used in the study. In addition to the Bureau&apos;s coal-pyrite flotation process, some of the coals were subjected to two-stage rougher-cleaner coal flotation for comparison. The results of this work showed that up to a 70-percent pyritic sulfur reduction could be obtained by flotation and that the Bureau&apos;s coal-pyrite flotation was superior to rougher-cleaner coal flotation. Because many of the coals retained far too much sulfur even after second-stage flotation treatment, it was concluded that these midwestern coals are more difficult to desulfurize by flotation than are the Appalachian coals tested in earlier Bureau experiments.

Jan 1, 1978

By Jack D. Ramsdell

The objective of this investigation was to make a preliminary evaluation of titanium-vanadium-zirconium, alloys using room-temperature tensile properties as criteria for selecting promising alloys for future critical studies. Arc-melted titanium-vanadium-zirconium alloys ranging in composition from 5 to 20 a/o (atomic-percent) vanadium and 5 to 30 a/o zirconium, were investigated to evaluate hardness, hot workability, and room-temperature tensile properties. Metallographic examination coupled with hardness measurements were used to follow structural changes and aging response. Room-temperature tensile properties were criteria for evaluating mechanical and engineering properties of the alloys.

Jan 1, 1960

By Heine Kenworthy

"INTRODUCTION 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 Sta¬tion 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 was present.A résumé of the ore-dressing treatment used in the Shenandoah-Dives mill follows. After crushing, the ore passes through a ball mill, the minus 5-mesh discharge of which is distributed to three tables. A finished lead concentrate is made on the tables, and the table tailing goes to the classifier which is in closed circuit with the ball mill. The classifier overflow is treated -by flotation to obtain a bulk sulfide concentrate at a relatively coarse size. The bulk concentrate is thickened and reground to about 95 percent minus 325-mesh before flotation treatment to separate a lead-copper and a zinc concentrate. A typical monthly average showed that the table concentrate contained about 45 percent lead, 1 percent copper, 4 percent zinc, 12 ounces of gold, and 40 ounces of silver; that the lead flotation concentrate contained '35 percent load, 6 percent copper, 7 percent zinc, 3.5 ounces of gold, and 50 ounces of silver; and that the zinc flotation concentrate contained 2 percent lead, 0.5 percent copper, 60 percent zinc, 0.15 ounces of gold, and 4 ounces of silver. Recoveries in salable products were roughly b5 percent of the lead, 70 percent of the copper, 45 percent of the zinc, 85 percent of the gold, and b5 percent of the silver."

May 1, 1948

By G. W. Jones

An important activity of the Bureau of Mines is the promotion of safety in mining and industry. As a part of this program, the Bureau determines the explosion hazards of combustible gases, vapors, and solids and investigates means of controlling and preventing explosions. The limits of inflammability (explosive limits) of combustibles are not only of theoretical but also of practical importance, because many industries at one time or another contend with explosive mixtures of combustible gases or vapors in their manufacturing processes. At present many new organic compounds are being manufactured, transported, and used in huge quantities which a few years ago were only laboratory curiosities.

Jan 1, 1941

By Eugene Frey

"INTRODUCTION The Good Fortune mine was sampled by an engineer of the Bureau of Mines in June 1944. Project 984 was set up under the strategic minerals program to make old workings accessible for this sampling program. Actual operations commenced June 1, 1944, and were completed June 30, 1944.The deposit was visited and discussed briefly by Sidney H. Ball 3/ of the Federal Geological Survey in the summer of 1906 and by H. M. Chance 4/ several times from 1887 to 1900.LOCATION AND ACCESSIBILITYThe Good Fortune mine is situated in the Hartville mining district in Platte County, Wyo., approximately 9 miles northwest of the town of Guernsey. The property is about 100 miles north of Cheyenne, Wyo. (fig. 1).ACKNOWLEDGMENTSIn its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metal¬lurgical Branch, O. C. Ralston, chief, analyzes samples and performs beneficiation tests."

Aug 1, 1947

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 D. W. Butner

As a part of the Bureau of Mines program for the discovery and development of critical and essential mineral deposits, the Darwin district, Inyo County, Calif., was chosen for investigation as a possible source of, tungsten ore. Two properties were active in the district at the time. One was producing tungsten concentrate and the other was preparing to produce tungsten concentrate as a byproduct in the milling of lead-zinc ore. The objective of the project set up by the Bureau was to investigate promising areas and to sample, thoroughly those which preliminary inspection indicated contained tungsten ore. Work was begun November 17) 1941, and completed January 19, 1942. In the course of the project, 18 localities were inspected and 9 were sampled. The following pages brief the history, note the location, and outline the physical features and geology of the district. The work performed by the Bureau of Mines is described and supplemented with assay maps.

Jan 1, 1949

By Martin J. Gavin

In an earlier paper (Karrick, Lewis, C. A convenient and reliable retort for assaying oil-shales for oil yield: Bureau of Mines, Reports of Investigations, Loral No. 2229, March, 1921. Reprinted in Eng. and Min. Jour, April 30, 1921, also in Mining & Met., May, 1921) which describes the apparatus and method used in the laboratories of the Bureau of times for assaying oil-shales, no mention is made of the quality of oil obtained when the apparatus is operated under conditions determined to be most suitable for producing highest yields of oils. So many inquiries regarding the nature of the oil have been received, that it seems advisable to present a short report on the subject. Experimental work indicates that it is possible to vary the quantity and quality of the oil obtainable with the assay retort from a given shale by varying the conditions of retorting. As an example, some figures that are averages for several closely agreeing tests are shown below.

Jan 1, 1921

By Foster Fraas

A comparison has been made between cubes and spheres in the matrix of the high-intensity wet magnetic separator. For two inclined plane surfaces, such as may occur with cubes, the maximum force value, H [dH-dx] is at the point of nearest approach and is much higher than the force resulting from adjacent spheres. Although the maximum force value for cubes is higher, it decreases more rapidly at increasing distances. The maximum force for spheres is at an appreciable distance from the point of nearest approach. At field intensities for magnetic saturation of the iron spheres, the force extends to further distances with greater uniformity approximating that of the constant force or isodynamic field. The force is also independent of the sphere diameter, which permits the scaling of the sphere diameter to provide changes in particle migration distances without changes in force gradient.

Jan 1, 1972

By Herbert R. Babitzke

The purpose of this investigation was to optimize the high-temperature properties of columbium and tantalum. Columbium and tantalum were combined with selected alloying elements to achieve solid solution and dispersion strengthening. Fifty-six alloys were evaluated to determine their formability, hardness, strength at elevated temperatures, and oxidation resistance. The following six alloys showed high-temperature strength: [Cb-15Hf-5W-2Zr-4Al-4Ti-2N Cb-15Hf -5W-5Zr Cb-15.3Ti-4.1Zr-13.7Hf Ta-20Hf-4Al Ta-30Hf-4Al Ta-20Hf-5W-4Al] At 1,200° C, the columbium alloys had strength values of 40,000 psi or greater, and the tantalum alloys had strength values from 50,000 to 58,000 psi. For a 2-hour test period at 1,000° C, weight gains of only 9 and 8 mg/cm2, respectively, were observed on oxidation testing of two alloys, Cb-15Hf-5W-2Zr-4Al-4Ti-2N and Ta-20Hf-5W-4Al.

Jan 1, 1968

By T. F. Anstett

The Bureau of Mines investigated the availability of platinum from known major deposits in market economy countries. Fifteen of these deposits contain demonstrated resources totaling 302 million troy ounces of platinum. Detailed geologic, engineering, and cost evaluations were performed on each deposit to determine its potential for platinum production. There are large amounts of demonstrated platinum potentially available from market economy deposits that were not analyzed owing to lack of adequate data or to technological limitations. These include 297 million troy ounces contained in the UG2 and Platreef of the Bushveld Complex, South Africa. This analysis indicates that about 11 0 million troy ounces (2.3 million ounces annually) of platinum are potentially available at the January 1980 producer price of $420 per troy ounce, nearly all from South Africa. An additional 85 million troy ounces occurring in Zimbabwean deposits would become available only through more than a quadrupling of that price. In order to meet projected world demand of 3.5 million troy ounces in 1990, platinum price may have to increase. Only one domestic deposit, the Salmon River in Alaska, is capable of producing platinum at $420 per troy ounce. Regardless of price, at assumed production capacities, domestic deposits could supply less than 10 percent of annual U.S. requirements.

Jan 1, 1982