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By Frank D. Lamb, Lloyg H. Baning

"The crushed-stone industry has long been troubled with the problem of producing a more or less cubical product for use as concrete aggregate. Its seriousness varies widely for each producer, depending upon the character of the rock employed for raw material and the ultimate use of the crushed stone. For many construction uses, such as the macadam or bituminous-concrete- type road, flat pieces are not objectionable and may even be preferable to more cubical rock. However, most specifications for concrete require that the stone must be reasonably free from flat and elongated pieces.The rigid specifications set by many contractors have resulted in the rejection of coarse aggregate that, except for the presence of an excessive amount of flat and elongated pieces, would be entirely acceptable. In many instances, if an efficient, economical method of removing flat and elongated pieces were available, local producers could meet the requirements of the contractor and thus eliminate the necessity for importing more cubical material.A brief investigation of the problem of removal of flat and elongated pieces from crushed aggregate, carried out at the Eastern Experiment Station of the Bureau of Mines, indicated that it is mechanically possible to remove flat pieces from crushed rock.TEST EQUIPMENTA number of mechanical devices are used by the coal industry for separating slate from coal; these depend upon the difference in shape of the crushed slate as compared with the coal. Such devices as shutter screens, spiral separators, and the Norman picker would be suitable for removing flat pieces from crushed rock in the same manner as they are used by the coal industry. None of these devices was immediately available for testing purposes, so an attempt was made to construct a simple device that could be used in commercial operations."

Sep 1, 1944

By R. Hogg, T. F. Dumm

"Abstract - With increasing interest in the physical cleaning of fine coal, there is a need for extension of the sink float analysis procedure to finer sizes. Problems arise, however, in ensuring complete dispersion of the particles in the heavy liquids. A procedure has been developed in which surfactants are used as dispersing agents, and solids concentration is minimized (using a simple formula to estimate the minimum weight needed for statistical reliability). Using centrifuges to increase separation rates and subsieve particle size analysis of the specific gravity fractions, a complete size specific gravity distribution can be obtained. Analyses have been performed on coal samples as fine as -10 µm.IntroductionTraditional gravity separation techniques such as jigging, heavy media and water-only cyclones, shaking tables, etc., have been used to remove impurities from coal ranging in size from about 15.cm (6 ln.) to about 150 µm (100 mesh). The coal washabilty or float-and sink technique ls a well-established procedure for determining the optimum extent to which a coal can be cleaned by such physical separation methods. Because of the desire to recover even finer coal fractions by gravity separation techniques, there is a need to extend the coal washabillty analysis into the ultrafine range. The purpose of this paper ls to describe some of the significant factors that influence fine particle specific gravity separation. Washability analyses have been performed on three ultrafine ( <10 µm) coal samples representing three general mining districts in Pennsylvania. Results of these analyses indicate that the washabillty technique can be successfully applied to ultrafine particles when proper care ls taken."

Jan 1, 1988

By Laird Crocker

This report describes a study of beryllium recovery from sulfate leach liquor by di-2-ethylhexyl phosphate (EHPA) solvent extraction in conjunction with caustic stripping. The work was one phase of Bureau of Mines research on process development for Spor Mountain, Utah, ores. Solution for the solvent extraction studies was prepared by sulfuric acid leaching of ore containing 0.6 pet BeO, Before solvent extraction of beryllium, the leach liquor was treated to prevent coextraetion of iron by either (1) removal of ferric iron by amine solvent extraction or (2) reduction of ferric iron to nonextractable ferrous iron by treatment with sulfur dioxide. Beryllim was extracted from the aqueous leach liquor by countercurrent multistage contacting with a kerosine solution of EHPA. The loaded organic solution was stripped with sodim hydroxide solution. Subsequently, beryllium hydroxide was precipitated by boiling the sodium beryllate strip solution and converted to beryllium oxide of 98 pct BeO-grade by calcining. Material of this grade can be directly processed into beryllium-copper alloy or be used as starting material for further refining to produce high-purity, nuclear-grade beryllium. Over 90 pct of the beryllium contained in the leach liquor was recovered as beryllia.

Jan 1, 1963

By Emory Smith

The preface of the United States Bureau of Mines Manual of First Aid Instruction contains the following paragraphs: One of the most important inquiries that Congress has authorized the Bureau of Mines to conduct relates to health condi- tions among those engaged in the mineral industries. Investigations made early with a view to bettering these conditions demonstrated the need of prompt care of injured miners, as, under the difficulties inherent to mining and other mineral industries; wounds seemingly unimportant, if not treated promptly, may become infected and possibly cause permanent crippling or even death of the porach. In the past many seriously injured persons have been treated by fellow workers ignorant of approved means of treatment and transportation and have been handled in such a manner as to cause suffering and to accentuate injuries to such a degree as to bring about permanent disablement. Accordingly, the need of general instruction in first aid became apparent. It must be recognized that the conditions in and about the mines, mills, smelters, quarries, oil fields, etc., usually present difficulties not found in large industrial centers where experienced surgeons are available and hospitals close at hand. Many mines are isolated and, when an accident occurs several miles underground, there may be a serious lapse of time before the injured person can be brought to the surface and taken to the hospital or given attention by a sur- geon who may have to come a long distance. Under such conditions it has been frequently demonstrated that, if effective first aid is not given, the injured person may die or become permanently crippled... First-aid instruction has been found to be an excellent aid3in pre- venting accidents. In addition to the immediate relief of injured persons, it has been found that most persons while in the act of practicing dressings for

Apr 1, 1931

By Marvin L. Whisman

Several parameters controlling the reproducibility of tritium determina¬tion in organic compounds by liquid scintillation counting were evaluated by the Federal Bureau of Mines. These included optimum volume of scintillator solution for maximum counting efficiency, reproducibility of counting a sealed commercial standard and comparison with duplicate counts on laboratory-prepared samples. The error introduced by using microliter pipets, optical differences in counting vials, reproducibility of counting organic samples where quenching is a factor, reproducibility of counting laboratory-prepared samples with an added internal standard, optimum ratio of internal standard activity to sample activity, effect of sample volume upon counting efficiency, count rate at which coincidence losses become apparent, and reproducibility of organic compound radioassay by the standard addition technique are outlined. From the evaluation of these parameters, a technique that can be applied routinely to organic compounds containing tritium has been established, and details are included in this report.

Jan 1, 1961

By John E. Pahlman

An increasing number of gold and silver mining operations are employing cyanide solutions to effectively dissolve silver and gold from finely disseminated ores. Many of these operations use small, packaged processing systems like the State of Maine filter system, which employs zinc precipitation of gold and silver. Solution-clarifying filters in these systems become blinded with calcium carbonate (CaC03) scale and require frequent (every 2 to 10 days) dismantling of the filter units for acid cleaning, This is a hazardous operation as it is not compatible with the alkaline cyanide leach solutions and may result in the evolution of toxic hydrogen cyanide (HCN) gas during cleaning and during any accidental acid spill. The Bureau of Nines has investigated an alternative, nonacidic method of cleaning blinded State of Maine filters that employs ethylene- diamine-tetraacetic-acid (EDTA) type chelating agents to dissolve the scale. In situ cleaning of a 150-st/d State of Maine filters with EDTA- type chelating agents was successfully demonstrated. Greater than 90 pct of the CaC03 scale was removed in about 10 min with circulation of 31 L of 2.5-pct-EDTA solution through the filter unit. The EDTA cleaning method not only eliminates the cyanide hazard in filter cleaning but is advantageous from the standpoint of operating costs and productivity.

Jan 1, 1986

By F. A. Skirvin

Purification techniques were investigated for removing low-level metallic impurities from tungsten hexachloride. These techniques included distillation) fused-salt scrubbing) zone refining) and adsorption. Fractional distillation of tungsten hexachloride was found to be an effective purification method. The impurity levels of molybdenum) iron) nickel) copper) magnesium) and manganese were reduced to provide a tungsten halide sample which contained a total of less than 10 ppm detectable metallic impurities. Purification by fused-salt scrubbing of tungsten hexachloride in a lithium chloride-potassium chloride eutectic produced a hexachloride product which was of approximately the same quality as that obtained by distillation. Zone refining and adsorption did not appear to be as effective as distillation or fused-salt scrubbing.

Jan 1, 1967

By Richard F. Link, George S. Koch

Through the use of statistical methods, estimates of metal content and tonnage of an ore body made by using data from 18 diamond-drill holes are compared with actual values established with data from 1,829 drift samples. The reliability of the estimates made from the drill holes is assessed in several ways. The relationship of metal content (assay-width product) to grade is explained. It is concluded that useful estimates can be made from 18 drill holes provided that reasonable assumptions are made and certain risks accepted. The ore body investigated is the Don Tomas vein of the Frisco mine, San Francisco del Oro, Chihuahua, Mexico.

Jan 1, 1964

By J. J. McClelland

The face area of a continuous mining section of an underground coal mine is the most dangerous area in the mine. Workers there are at nearly twice the risk of death or disabling injury than those in other parts of the mine. Despite extensive training of miners and improved equipment and mining methods, fatality and injury rates have remained constant during the past few years. It is clear that advanced research is necessary to apply new technologies or modify work procedures to solve the continuing problem of the loss of lives and the numerous injuries at the mine face. A U.S. Bureau of Mines research program is developing a Reduced-Exposure Mining System (REMS) that relocates personnel operating the mining machinery at the face away from the hazards to a nearby haven of relative safety. REMS uses proven technologies of computer automation and robotics to help control the operation of the mining machines at the face, while personnel are moved away to a nearby, safe control room. In this protected, well-ventilated environment, they can supervise or control the operation of the machines while viewing what the machine is doing using video and graphic display monitors.

Jan 1, 1994

By E. W. Parsons

Permanent support of the back is an important economic factor in maintaining a tunnel or other underground opening in condition to render the service for which it was driven. Timber has been most commonly used for support in tunneling and drifting because of its strength and ease of installation. Even when treated for decay, however, timber is subject to deterioration and, over a long period of time, should not be considered a permanent support. Concrete support or lining is permanent and has been used in tunnels of every size for many years but has been almost exclusively cast in place, a difficult, costly process. This report deals with the design and installation of precast concrete supports to combine the best features of both methods.

Jan 1, 1958

By Harry R. Johnson

Domestic expenditures by the U.S. petroleum industry have exhibited distinctive shifts in emphasis over the past 20 years. From the end of World War II to 1955, expenditures for all phases of the industry expanded. Although over one-half of all expenditures were for production, the relative emphasis was changed after 1956-58 from production toward processing and marketing. The period 1967-69 marked the beginning of a return to emphasis on exploration and production. These trends in expenditure patterns are logical and rational when related to domestic and international economic conditions and to the widespread application of improved production technology. As the immense job of developing the oil resources of Alaska and other regions begins, the petroleum industry will continue to turn to external sources for working capital. Long-term debt will probably be the principal method of external financing through 1970, but a definite shift toward new common and preferred stocks will be made. Higher product prices may be sought by the petroleum industry, but the economics of crude-oil production, changes in the tax structure, and possible changes in the oil imports control program make the price structure of crude oil and crude-oil products unpredictable at the present time.

Jan 1, 1970

By N. S. Dalal, X. Shi

"This study reports a new property of the important NAD(P)H-dependent flavoenzymes, glutathione reductase, lipoyl dehydrogenase and ferredoxin- NADP oxidoreductase, that can catalyze a one electron reduction of metal ions such as chromium(VI) and vanadium(V). During the enzymatic reduction process, molecular oxygen is reduced to H2O 2 , which reacts with the reduced metal complexes to generate hydroxyl radicals. Since the hydroxyl radicals have been suggested to play an important role in Cr(VI) toxicity, this study provides a basis for a recent observation that Cr(VI) mutagenesis is strongly oxygen dependent. These results also point to an enzymatic pathway for the metabolism of some metal ions and concomitant generation of hydroxyl radicals. l. INTRODUCTIONThe purpose of this communication is to report that some important NAD(P)H-dependent flavoenzymes (glutathione reductase, lipoyl dehydrogenase and ferredoxin-NADP+ oxidoreductase) can catalyze one electron reduction of metal ions such as chromium(VI) and vanadium(V) and simultaneously reduce molecular oxygen to generate Hi02 and, eventually, the ""OH radical. This finding is significant because (i) the known substrates for the flavoenzymes are organic species and not metal ions, and (ii) the report on the enzymatic formation of the ""OH radical provides a new pathway for understanding the mechanism of genotoxicity of some non-ferrous metal ions. For example, it has been suggested that OH radical is likely to be the major species responsible for Cr(VI) genotoxicity [1-5). The 'OH radical is generated through the reaction of Cr(V) complexes with cellular Hi02 [4,5]. Cr(V) itself is known to be generated from Cr(VI) in various biological systems, in particular, microsomes [ 6), mitochondria [7] and mitochondrial electron transfer chain complexes [8]. However, no specific enzyme responsible for the Cr(V) generation has been identified except possibly glutathione reductase [4]. In this study we have used ESR and spin trapping techniques to show that the flavoenzymes can generate Cr(V) and provide a catalytic redox cycle for 'OH formation in such reactions. Herein we present our results on Cr(VI) and summarize those on other systems. Correspondence address: N.S."

Jan 1, 1990

An active list of permissible explosives was published in December 1936 as part of Bureau of Mines Report of Investigations 3324, under the title "Active List of Permissible Explosives and Blasting Devices Approved Prior to July 31, 1,936." This list included 170 brand names. Changes in the list that have been authorized to June 30, 1937 placed 35 additional brands of permissible explosives on the active permissible list as a result of tests, changes in brand names, or transfer from the inactive list. Ten permissible explosives were transferred from the active to the inactive list. The present list contains 196 brand names, one explosive having been placed on the list subsequent to June 30, 1937. The brand names of the permissible explosives placed on the active list are as follows: [ ]

Jan 1, 1937

By A. C. Fieldner, G. W. Jones

Tests were made at the Government Fuel Yard , operated at Washington , D. C. by the Bureau of Mines , Department of the Interior , in order to determine and improve the adjustment of the carburetors on the trucks used for transporting coal from the Fuel Yard to the different Government buildings in Washington . The tests were made possible through the hearty cooperation of G , S. Pope , engineer in charge of the Fuel Yard . Joseph Burrows and A. E. Foote of the garage department assisted during all the tests and supplied information on the mileage obtained by the trucks for the months preceding and succeding the time the tests were made . The Mack trucks used range in capacity from 2-1/2 to 7-1/2 ttoonnss .. The majority of the carburetors were Stromberg G- 3 type , as shown in Table 2. During the winter months , when the demand for coal is heavy , from 30 to 35 trucks are used . At the time the tests were made , only about ten of the trucks were in daily use , owing to the small demand for coal during the summer months , and scarcity due to labor conditions . Samples of the exhaust gas were taken on the trucks kept in service for summer hauling in order to determine the carburetor adjustment as used . Changes were then made to a more economical adjustment wherever possible , without sacrificing flexibility of operation and power . In every case the adjustments were maintained for maximum power , but were adjusted to the leanest position to give that power . In all but one case the carburetors were found to be adjusted too rich for maximum power and economy . These results are considered in detail in a later part of this report .

Jun 1, 1923

By Earle S. Burnett

This report outlines the experimental procedures for using a Burnett apparatus to obtain compressibility coefficients for multiphase, multicomponent fluid mixtures. The conventional Burnett method is described briefly whereby multiphase compressibility data can be obtained by first determining the compressibility factor, Z, as an isothermal function of pressure alone. Then starting at conditions of temperature and pressure where Z is known, the fluid is cooled at constant volume to some lower temperature at which the resulting pressure is measured, and a corresponding value of Z is obtained from a fundamental relationship between compressibility factors, pressures, and temperatures at constant volume. The isochoric treatment of the fluid, extended to still lower temperatures and along other isochors, eventually results in compressibility determinations for the whole two-phase system thus covered experimentally.

Jan 1, 1963

By Alan D. Hartman

Instabilities in electric steelmaking furnace arcs cause electrical and acoustical noise, reduce operating efficiency, increase refractory erosion, and increase electrode usage. The U.S. Bureau of Mines is investigating methods to stabilize these arcs. To perform experiments to test new hypotheses, Bureau researchers designed and instrumented an advanced, experimental single-phase furnace. This report describes this furnace, which was equipped with high-speed data acquisition capabilities for electrical, temperature, pressure, and flow-rate measurements; automated atmosphere control; ballistic calorimetry; and view ports for high-speed cinematography. Precise environmental control and accurate data acquisition allow the statistical design of experiments and assignment of rigorous confidence limits when potential furnace or procedural modifications are tested.

Jan 1, 2010

By M. D. Carver

The purpose of this investigation was to determine the effects of variations in content (near the residual level) of the impurities aluminum, nitrogen, manganese, and copper on the corrosion rate in pressurized hot water and in pressurized steam of zircaloy-3, a zirconium-base alloy of 0.25 percent tin and 0.25 percent iron. Thirty-five 10-pound ingots were cast with the appropriate additions of impurity elements, and these were converted to wrought sheets. These specimens were then tested both in water and in steam. The analysis of the resulting data showed that in environments of either pressurized hot water or superheated steam, corrosion rates increased with increasing content of aluminum, nitrogen, or manganese, but were not affected by variations of copper. The effects of aluminum and nitrogen were found to be greater than the effect of manganese. INTRODUCTION At the request of the Atomic Energy Commission (AEC) in August 1956, the Federal Bureau of Mines, in cooperation with Bettis Plant of Westinghouse Electric Corp., began investigating the effects of certain impurity elements on the corrosion rates of zircaloy-3 in pressurized hot water and in pressurized steam. It was necessary to know these effects in order to set control limits on residual impurity levels in zirnaloy-3, intended for heat transfer service in the nuclear reactor of the pressurized water type. A factorial expert it was designed by Westinghouse statisticians. The Atomic Energy Commission provided raw zirconium sponge purchased from Wah Chang Corp. The Bureau&apos;s laboratory at Albany, Oreg., made material of different combinations of impurity levels and subjected the material to corrosion tests. This report will describe the work done at the Bureau laboratory and will show, quantitatively the effects of different residual levels of aluminum or nitrogen, or manganese or copper on corrosion rates.

Jan 1, 1961

By W. E. Wallace, S. -G. Xing, M. J. Keane, J. C. Harrison

"SummaryDiesel-exhaust particles from two sources were dispersed in aqueous mixtures of dipalmitoyl phosphatidyl choline, a major component of pulmonary surfactant, and were tested for genotoxicity. Diesel samples from the same sources were extracted with dichloromethane and transferred into dimethyl sulfoxide and subjected to the same assays. Both types of extractions yielded similar results in both the Salmonella mutagenicity assay and the sister-chromatid exchange assay using V79 cells. After separation of the samples into supernatant and sediment fractions, the activity of both diesel samples was shown to reside exclusively in the supernatant fraction for the solvent-extracted samples, and exclusively in the sedimented fraction for surfactant dispersed samples. These findings indicate that genotoxic activity associated with diesel particles inhaled into the lung may be made bioavailable by virtue of the solubilization / dispersion properties of pulmonary surfactant components.While diesel engine emissions are associated primarily with transportation, they are also very common in the workplace. Estimates for the U.S. are that as many as 1.35 million workers in as many as 80 000 workplaces are exposed to the combustion products of diesel engines (NIOSH, 1988). These occupations include, but are not limited to mining, agriculture, motor vehicle maintenance, fork lift truck driving, truck driving, and tunnel and bridge operation."

Mar 1, 1992

By W. L. Falke

Research was conducted to develop methods on a laboratory scale for recovering manganese from manganiferous slimes and limestones . The procedure is a low- temperature modification of the carbamate process , in which manganese is dissolved and the valence reduced by treating slimes and limestones with controlled amounts of sulfurous acid . Manganese ( II) hydroxide is precipitated and leached with ammonium carbamate solution , and manganese carbonate is separated by warming the leach solution . A major portion of the reagents is regenerated and recirculated . About 75 percent of the total manganese in manganiferous slimes , and from 50 to 75 percent of the total manganese in manganiferous limestones , are recovered as manganese carbonate containing 45 percent manganese .

Jan 1, 1964

By John W. Frey

This paper presents 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 rights of American citizens to explore for minerals and to own and operate mines in various foreign countries . This interpretation of the mining law of Australia was first compiled from the best information available in Washington; it was then sent to the American Consulate General , in Australia, where through the direction of Thomas H. Robinson , American consul in charge , it was submitted for criticism to the mining authorities in the various States of Australia , whose suggestions have been incorporated in this digest .

Sep 1, 1930