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By James P. Bennett

To identify construction materials for emerging technology in chemical and metallurgical processes, the Bureau of Mines investigated the acid resistance of ceramic materials. Eight commercial ceramic materials comprising two red shale, two fire clay, a silica, a five-claybonded silicon carbide, a carbon, and a high-alumina brick were evaluated. Samples were exposed for 110 days to 20 wt pct HCl at 50°, 70°, and 90° C and to 30 wt pct HCl at 70° C. Statistically significant changes in cold crushing strength, volume, and weight were generally small or not detected. The leach rates of Al, Ca, Fe, K, Mg, Na, Si, and Ti ions were monitored. The carbon brick sample had the best acid resistant properties with a maximum total leached ion weight loss of 0.004 wt pct. The silicon carbide, the silica, and one of the fire clay bricks also had excellent acid-resistant properties.

Jan 1, 1983

By Oliver C. Fursman

This work was conducted to determine the feasibility of producing aluminum-silicon alloys in a pit-type, three-phase electric-arc furnace. Two carbon-lined furnaces were used in the tests. The power input ranged from 120 to 240 kw. in the small furnace and from 420 to 460 kw. in the large furnace. Energy consumption ranged from 5.3 to 11.5 kw.-hr. per pound of alloy produced and electrode consumption, from 240 to 510 pounds per ton of alloy produced. A wide range of crude aluminum-silicon alloys was produced by direct smelting of clays or similar aluminum silicate raw materials, using hogged fuel or wood chips as the major source of carbon in the furnace charge, and silicon of high grade was produced by smelting quartz. The aluminum content of the aluminum-silicon alloys ranged from 15 to 55 percent. Alloys produced from a white opaline-silicate clay were relatively free of iron, titanium, and other impurities. Those produced from western fire clays and kyanite, although richer in aluminum, contained considerable amounts of impurities. The purity of the alloys depended largely on the composition of the raw materials.

Jan 1, 1960

By G. S. Rice

The recommendations of the Bureau of Mines on rock dusting practices are embodied, except in a few details, in the Recommended American Practice for Rock-Dusting Coal Mines to Prevent Coal-Dust Explosions, approved by the American Engineering Standards Committee. December 30, 1925. It is specified that the dust to be used is of a elm that all will pass through a sieve having 20 meshes per linear inch and that 50 per cent or more will pass through a sieve having 200 meshes per linear inch. Thus the coarsest size of dust and the minimum proportion of fine dust are specified, but the specification does not indicate whether a larger proportion of fine dust would be desirable. There have been advocates of the use of that size of rock dust of which the particles would all approach 200-mesh in fineness. Explosion tests were made in the Experimental mine in the earlier period of testing which indicated that the finer rock dust is somewhat more effective under test conditions, but not sufficiently so to Justify the cost of finer grinding of the dust; also there are some disadvantages of finer dust described hereafter.

Jan 1, 1930

By P. R. Bremmer

As part of a program to devise alternative technologies for producing alumina from domestic resources, the Bureau of Mines investigated the leaching of calcined kaolinitic clay to form basic aluminum chloride solutions. Bench-scale experiments were conducted for single-stage batch leaching with AICl3 solution and three-stage countercurrent leaching with substoichiometric HCI. Variable conditions of clay calcination and leaching were studied to determine their effects on aluminum extraction and pregnant liquor composition,

Jan 1, 1984

By H. Stuart Auvil

Twelve samples of run-of-oven coke were taken at coke plants in the United States and Canada. Sampling procedure was directed toward obtaining the highest possible degree of uniformity in the gross samples, so that variations in results caused by sampling variations were at a practical minimum. Under these conditions the standard deviation of the screen analysis test on 500-pound samples is found to range from 1.2 percent for the 1-inch screen to 4.5 percent for the 5-inch screen. At present, the A.S.T.H. standard method of test requires that results be reported to the nearest 0.1 percent. This implies a higher than actual degree of precision, and revision of the report required by the method is suggested. Much larger Samples than are generally tested are required to reduce normal testing errors to a point where they are not appreciable fractions of the total variations found in a smoothly operating plant. For example, it is deduced that over 100,000 pounds of coke must be screened to determine if ordinary day-to-day variations in screen analysis have appreciable effects on the performance of a blast furnace.

Jan 1, 1950

By R. M. Becker

As part of the Bureau of Mines program for examining the Nation's iron and titanium resources, magnetic, gravity, and geologic surveys were made to permit an estimate of the extent and magnitude of the Iron Mountain, Colorado, titaniferous magnetite deposit. Gabbro is the dominant rock type of the area. Within the gabbro are lenses of titaniferous magnetite, 5 to 25 feet wide and as much as several hundred feet long. These lenses comprise a zone which has scattered occurrences of magnetite for 2,200 feet. To the west, the gabbro grades into a strip of pyroxenite that in turn borders a large monzonite mass. A wedgelike broadening of the pyroxenite with depth accompanied by little or no increase in the titaniferous magnetite is considered a reasonable interpretation of the field data. The iron deposits appear to be limited and discontinuous.

Jan 1, 1961

By J. A. Sutton

In connection with, a stream-pollution-research project, a colorimetric method was developed for concentrations of 1 to 30 p.p.m, of pine oil in water. The method depends on the stable bluish-green color produced when pine oil is reacted with vanillin-hydrochloric acid reagent at 60° C. for 25 minutes. The colorimetric reaction actually determines alphaterpineol, the principal component in pine oil. Some waters may require a special preparation in which ion-exchange resins are used to remove interference. ACKNOWLEDGEMENTS The author wishes to express his appreciation to A. A. Berk, chief of the Industrial Water Branch, Bureau of Mines, for helpful advice and encouragement during the progress of this work and to B. P. Martinez, chief of the Stream Pollution Research Section, for assistance with the manuscript. Thanks are also due to W. D. Bishop of the Hercules Powder Co., Wilmington, Del., for supplying the principal components of pine oil.

Jan 1, 1953

By Raymond Derzay

This publication is intended to be of value to the mineral industry in establishing and maintaining effective programs for preventing noise-induced hearing loss. Factors involved in this loss and the need for and the requirements of an effective hearing conservation program are discussed. The legal and legislative history of compensation for hearing loss is briefly reviewed. A review of statutes is not attempted since several States have recently modified) or are in the process of modifying their laws regarding permissible noise exposures) required hearing protection) and/or compensation for hearing loss. A review of other aspects of the problem of industrial noise in terms of medical, physiological) and psychological frames of reference is included. A hearing conservation program is described in detail. Appendixes detailing the names and addresses of a few equipment suppliers are included. References are provided for those who may wish to delve more deeply into the medical, technical, and scientific considerations of noise and its effect on man.

Jan 1, 1972

By Khamis Y. Haramy

This U.S. Bureau of Mines report describes the use of Bureau-developed flat and cylindrical hydraulic borehole pressure cells. A brief description of the fabrication, installation, and pressurizing equipment is given and pressurizing procedures are discussed. Theories available on evaluation of data from the flat and cylindrical pressure cells and examples of data analysis and stress evaluation are also presented.

Jan 1, 1991

By Michael D. Balen

During the years 1987 through 1989, the Bureau of Mines Alaska Field Operations Center (Bureau) in cooperation with the Western Field Operations Center and the Alaska Division of Geological and Geophysical Surveys (ADGGS), conducted mining, geological, and geochemical investigations in the 5.7 million-acre Valdez Creek Mining District (VCMD). This investigation was conducted as part of the Bureau's continuing Mineral Land Assessment (MLA) mining district studies program. The Bureau's MLA program is designed to provide reliable and comprehensive mineral resource information that supports mineral resource policy and land use decisions made by Congress and Federal land management agencies. The information also provides the basis for decisions that would expand the domestic supply of important mineral resources, primarily strategic and critical minerals. Much of the MLA work is done jointly with cooperating State or U.S. geological surveys.

Jan 1, 1992

By B. W. Moore

The U.S. Bureau of Mines investigated the separation of heavy rare-earth elements (REE) in an ion-exchange process. An ion-exchange column consisting of two sections, a loading section and a separation section, provides high levels of REE loading and good REE separation with an expected processing cycle of less than a month, while current ion-exchange technology requires more than 5 months. A different resin is used in each section: sulfonic resin in the loading section and iminodiacetic resin in the separation section. The separation section is further divided into two segments: the first conditioned with NH4 and the second with acid. Erbium is loaded onto both segments of the separation column as a retaining ion. Bands of mixed REB eluting between separated bands of pure REB were recycled directly to the column. Without mixed-band recycle, over 80% of the REE eluted from the column was separated into fractions with 99% purity of each element; with such recycle, the percentage of separated elements can be increased to around 90%.

Jan 1, 2010

By Robert K. Koch

The reactions of alumina and alumina monohydrate with wet hydrogen fluoride gas were studied by the Federal Bureau of Mines to determine the feasibility of producing commercial-grade aluminum fluoride from offgases generated by pyrohydrolysis of siliceous fluorspars. The test results showed than an aluminum fluoride reactor operating at maximum efficiency could retain 96 percent of the fluorine contained in off-gases generated by pyrohydrolysis of siliceous fluorspar. The requirements are a reactor temperature of 200° C. and a reactor entrance gas containing 5 mole-percent hydrogen fluoride. Partial pressure equilibrium constants were determined for the reaction of alumina monohydrate and wet hydrogen fluoride gas from 200° to 350° C. and for the reaction of alumina and wet hydrogen fluoride gas from 350° to 700° C. Both reactions are reversible, and they proceed in directions that are dependent upon the temperature and the relative HF:H2O concentration. Logarithms of the equilibrium constants were used to plot the reaction isobars; these can be used to calculate the theoretical maximum efficiency of a reactor processing wet hydrogen fluoride gas between 200° and 700° C. The theoretical maximum efficiency decreases with increasing temperature.

Jan 1, 1961

By Bernadette Michalski

Although hydrocarbons accounted for more than 60% of Bahrain's income and more than 80% of export earnings, this island nation sustained one of the more diversified economies in the Gulf Region. The availability of low-cost natural gas for electric power has fostered the development of a significant aluminum refining and manufacturing industry with emphasis on vertical integration. The Bahraini iron pelletization plant, closed since 1986 due to financial problems, was scheduled to reopen by early 1989. Commodity Review Metals.-Aluminum.-Aluminium Bah-rain Bsc (Alba) attained record high production levels in 1988 taking advantage of favorable aluminum prices, which averaged over $2,000 per ton as compared with less than $1,500 per ton in 1987. Net aluminum production was nearly 13,000 tons over design capacity. Fewer standard ingots (52,081 tons as compared with 79,685 in 1987) were produced as Alba concentrated on higher value added products such as rolling ingots (42,324 tons as compared with 32,125 tons) and extrusion billets (60,934 tons as compared with 46,618 tons).

Jan 1, 1990

By L. C. IlsLey

Minin,g Qr col-cu.ttint till:I chines are 1?;\i9ng the _m9t wideiy .used de1sses ()f mining equipment.· These 1T:.i:1Chines ,.--re practicaily t-tl\·operc1_ted eiyher_by compressed .iir or by electric. ·motors. According to &.ta• compiled _ from the 122. issue COAL CATALOG\JE. OJMEINED WITH; OOAL "FIELD 'pf!:fC'TOTl1, bf 7,088. mnes from which reports were obttiined there -are 3895 mines that u.se coal-cutting eql;lipmen:ts,, 'f'hi report lists 20,031: r.ct:lchines, 17,&75 being operated by·elct:i.c.m<;>_tors··:r;id :the remtiinder by compressed i.r motors,· ,-. · ', .. . · .. ··, .. _ ,· .,, .. .. . . . . . : ; "'l t:: On tl.Ccou-nt .. of the wide· use of coc:11-cutting -.:i"cliine_- any Stat!;ls have issued regulationa as "to their operation dnd be to safety precautions that.should be observed J especially in gaseous mines.

Oct 1, 1922

By H. M. Smith

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Jan 1, 1927

By F. E. Cash

Among petroleum refinery employees and officials throughout the United States there has been marked effort to reduce accident frequency and severity. For the interest and benefit of refineries both in Louisiana and in other petroleum-refining States it has been possible to obtain from five refineries, representing 70 per cent of the production of Louisiana, tae accident experience for the past 3 to 6 years. The companies concerned have requested that their names be not used. For tide reason the four plants listed and discussed are designated as refineries A, E, C, and D. The size of the plant as regards largest to smallest number of employees is indicated by the alphabetical order.

Jan 1, 1933

By James W. Ballard

The facts are generally accepted that an atmosphere containing large quantities of any dust is objectionable to breathe and that some dusts are more dangerous than others. Therefore, knowledge of the composition of dusts is important in evaluating the hazard entailed on exposure. At present, free silica, of which quartz is the most abundant form, is considered one of the most significant dusts, from the standpoint of pneumoconiosis, and one State5/ has established permissible limits of air dustiness on the basis of the free-silica content of rock. The amount of free silica in materials used for rock dusting also has been limited.6/ Determination of free silica or quartz, therefore, is important.

Jan 1, 1940

By J. Burlin Johnson

This report describes an investigation of the relationship between crater dimensions formed in laboratory blasting experiments and the mechanical properties of the material cratered. Scaled field data have been included when available. The results show that tensile strength and possibly other mechanical properties may be useful in predicting maximum crater dimensions.

Jan 1, 1963

The Bureau of Mines performed cratering experiments in a homogeneous granite to test scaling laws for charge weights of 0.00476, 0.0220, 0.0900, 0.304, and 1.03 lb. Agreement among the data was best when empirical scaling exponents greater than one-third were assumed. Although the analysis showed that the best empirical scaling exponents were 0.37 for crater volume, 0.38 for crater radius, and 0.39 scaling for crater depth, all three crater dimensions could be scaled with a 0.38 scaling exponent.

Jan 1, 1970

By E. C. Lane

The motor gasoline that is being marketed in the United States this winter is in general, more volatile than that sold a year ago. This increase in volatility is shown by a lowering of the distillation temperatures, ranging from 2°F. at the average initial boiling point to 5°F. at the average end point. During the past eight and. one half years the Bureau of Mines has made semi-annual surveys of the gasoline marketed in the United States, the survey Just completed being the seventeenth in the series. The cities in which samples have been collected, have been chosen as representative of the more important marketing territories, as it is obviously impracticable to obtain a sample of every gasoline sold in the entire country. Samples were collected in Boston for the first time since 1919. It was believed advisable to include samples from that district in order to give a better balance to the survey for the country as a whole.

Jan 1, 1928