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By J. G. Donaldson

Cobalt-tungsten binary deposits were formed in laboratory experiments by hydrogen reduction of the anhydrous mixed vapors of cobaltous chloride and tungsten hexachloride. The materials were sublimed in seperately heated zones of reaction tube and were transported in a stream of purified helium into the deposition section of the tube where the chloride gases were reduced to metal by a countercurrent flow of hydrogen. Heattreating of the near stoichiometric binary metallic deposits converted nearly all to the intermetallic compound Co3W, however, small quantities of both cobalt and tungsten remained. Mechanical tests showed that the tensile strength of heat-treated 75 percent cobalt-25 percent tungsten deposits was twice as high as that of similarly treated deposits of cobalt.

Jan 1, 1965

By H. Polat, Q. Hu, S. Chander

"The collection efficiency of dust particles was determined in a laboratory dust chamber equipped with a water spray. Measurements were made in the presence of selected nonionic, cationic and anionic surfactants. For the nonionic and the anionic reagents, efficiency was maximum in a narrow range of concentration. The surfactant concentration corresponding to high collection efficiency was usually much below the commonly used concentration of l "", however. In comparison, much higher collection efficiency was observed for a cationic surfactant at extremely low concentrations. For delineating the mechanism of capture of dust particles, surface tension and contact angle results were used to obtain a correlation between the work of adhesion and the efficiency of collection. Such a correlation was reasonable for the nonionic surfactants but not for charged surfactants. In the latter case, electrostatic interactions between charged droplets and particles were more important, especially for the cationic reagent. INTRODUCTIONSeveral methods are used to control dust in mines. These include: ventilation, foam, scrubbers and sprays. This article is concerned with improving the effectiveness of water sprays, which are widely used to remove dust particles during continuous mining, by adding small quantities of surfactants. Water sprays produce small droplets which act as collectors of dust particles suspended in air. Sprays directed at the actual source of dust have the additional property of wetting the coal before the ·particles become airborne (Hamilton, 1974). Wetting agents, also called surfactants, arc known to play an important role in many applications where dust is a problem. However, conflicting reports exist in the literature with regard to the effectiveness of surfactants in water sprays (for a review, see Chander et al., 1988). In spite of the conflicting reports, the use of surfactants for dust control has increased over the years. In a recent study by the Bureau of Mines, a 27'6 reduction in respirable dust levels was observed in a mine test when surfactants were added to sprays (Foley, 1991)."

Mar 1, 1992

By W. V. Kuster

The investigation described in this report is part of a survey by the Federal Bureau of Mines of the titanium resources of the United States. The purpose of this project was to study a typical coastal deposit of beach sands in the Middle Atlantic States, particularly in the area surrounding the Delmarva Peninsula. The field investigation consisted of a reconnaissance survey of the Eastern Shore of Maryland, followed by surface sampling and drilling of the sands on Assateague Island, off the Atlantic coast of Maryland. The study covered the period January-December 1957. Detailed analyses were made of 5-foot sections of eight drill holes along the Maryland section of the island. The heavy-mineral fraction of these samples was separated by sink-float tests, using acetylene bromide as the heavy liquid. The minerals comprising the heavy fraction were examined microscopically, and mineral counts were made on selected samples.

Jan 1, 1959

By Richard F. Hewlett

Use of digital computers makes possible a more efficient and complete analysis of data from a mineral deposit . This computer program was written and used during an investigation into the efficiency of methods of computing grade and tonnage of ore , wherein it was necessary to make repeated computations involving different combinations of data . This investigation was part of a continuing program of sampling methods research at the Bureau's Denver Mining Research Center.2-4 This program is designed to compute tonnage and average grade for 40 cutoff grades using either the statistical or polygonal methods . tational rate is from 200 ( input bound ) to 1,400 assays per minute , depending on the use of either individual ( one assay per card ) assay- interval length or

Jan 1, 1963

By R. H. Harrison, D. R. Douslin

The thermodynamic properties H - H° , (H - H° ) /T , S - Sideal , S - S° Fide al F - F° , (F F° ) /T , and activity coefficient Y for perfluorocyclobutane were calculated as functions of temperatures ( 115.22 ° to 350 ° C) and molal density (0.75 to 6.5 moles / liter ) . Improved analytical and graphical correlating techniques are described .

Jan 1, 1964

By S. E. Khalafalla

The Bureau of Mines investigated variations in the activation energy for the carbon monoxide reduction of magnetite and ferrous oxide with respect to the state of aggregation of the oxide material. Reduction phenomena can only be satisfactorily explained by including an adsorption step in the reduction process. Summation of the values of the exothermic heat of chemisorption and the variable apparent activation energy for reduction yields a nearly constant value of about 50 kcal for either ferrous oxide or magnetite regardless of whether they are aggregated in pelletized form or coarsely crystalline particles.

Jan 1, 1965

By John E. Kelley

Laboratory equipment, which simulates abrasive impacts between steel and minerals that might be present during pneumatic transport of coal, was used by the Bureau of Mines to characterize the potential explosion hazard of such collisions in an atmosphere of fine coal dust, air, and methane. A variety of coal mine rock materials, including sandstone, limestone, and pyrite-bearing limestone, were impacted with specimens of pipeline steel. Tests were con-ducted in atmospheres containing zero to 6.4 vol-pct methane mixed with zero to 300 mg/l coal dust. Coal dust in air alone was not ignited by abrasive impacts, but additions of as little as 1 vol-pct methane to the coal dust and air mixture resulted in ignitions. Steel impacting against sandstone caused ignitions in mixtures of coal dust, air, and methane, and the probability for ignitions increased with an increase in methane. No ignitions occurred with impacts of steel on lime-stone or pyrite-bearing limestone, even when large showers of sparks were produced. Studies of the effect of tangential collision velocity showed that no ignitions of coal dust, air, and methane occurred below 900 fpm (4.57 m/sec). Ignitions in coal-air-methane mixtures were found to be caused by a hot friction-induced smear on the impacted rock at the impact site rather than by sparks. High-speed photography was used to verify this observation.

Jan 1, 1976

"The following articles were produced through funding under Generic Mineral Technology Center for Respirable Dust research. Full articles appear in the proceedings, 3rd Symposium in the Mineral Industries, published in 1991 by the Society for Mining, Metallurgy and Exploration, Inc.Personal Diesel Exhaust Aerosol SamplerV.A. Marple, K.L. Rubow, and Y. TaoParticle Technology, Mechanical Engineering Department, University of Minnesota, Minneapolis, Minnesota(Section ill. Diesel I: Diesel Particulate Measurement, pp. 73-81)Abstract. Techniques are being developed for measuring the mass concentration of respirable diesel exhaust particles found in underground coal mines. Studies have been conducted over the past five years to investigate size selective 18Dlpling techniques to measure the respirable mass concentrations of diesel exhaust and mine dust aerosol particles in underground coal mines. Results from these studies have been used to develop design and performance criteria for a personal diesel exhaust aerosol sampler.Three personal diesel exhaust aerosol samplers have subsequently been designed and evaluated in both laboratory and field settings. These samplers use size selective classifiers for the determination of respirable mass concentrations of mineral dust and diesel exhaust particles. Their designs are based on the premise that diesel exhaust particles are predominantly less than 0.8 µm while mineral dust is greater than 0.8 µm.One design, selected for field evaluation, consists of a 10 mm nylon respirable dust cyclone followed by a 0.8 µm cutpoint impactor and afterfilter. The cyclone removes the nonrespirable particles while the inertial impactor state, collects the mineral dust on an impaction plate and allows the diesel particles to penetrate to an afterfilter. The two sample fractions of the respirable particles ( <0.8 µ.m and >0.8 µm) are gravimetrically analyzed to determine the concentrations of the diesel and mineral dust portions in the respirable coal mine aerosol."

Mar 1, 1992

By Carlton E. Brown

[The purpose of this report is to present results of tests on the effectiveness of a spray of water mist, commonly called compressed-air water blast or water blast, in reducing the concentration of dust present in the air shortly after blasting and during mucking of the blasted material. Many observations have been male on the effectiveness of such ,sprays, but published quantitative information on comparative dust concentrations with and without their use, obtained by dust-sampling methods in use in this country, is rare if not absent. Tests conducted. in South Africa about 19164/ and more recently in England5/,6/ have shown that such sprays reduce the dust concentration to very low values within a fen minutes after blasting.]

Jan 1, 1938

By P. D. Kovscek

High-pressure streams of water, known as water jets, can be used to improve the cutting efficiency of mechanical bits. During prior testing by the Bureau of Mines, the cutting performance of a longwall shearer, equipped for water-jet-assisted cutting, was evaluated. The performance of the shearer did not improve while using water jet assist because the pressure of the water delivered to the rock surface was inadequate. The study, described in this report, resulted in a determination of the major cause of water pressure loss on the shearer, and an evaluation of the techniques for increasing the water pressure at the rock surface. The results show that the major pressure loss, which occurred between the nozzle and rock surface, is directly affected by the amount of fluid turbulence that develops just upstream from the nozzle. Preventing a sudden change in the direction of the flow channel can increase the stagnation pressure as much as 400 pct. Smoothing the surface of the flow channel in the shearer bit block would increase the stagnation pressure delivered to the rock surface by 35 pet.

Jan 1, 1989

By J. M. Mutmansky, L. Xu

"This paper outlines the results obtained when sampling twenty underground coal mine sections, each in a different mine. The sampling effort was oriented toward a detailed characterization of coal mine dusts and thus eight-stage Anderson Model 298 impactors were used as the primary collection instrument. This instrument allowed a rather detailed size distribution for each of the particulates sampled. Because four of the mines used diesel outby equipment and/or diesel shuttle cars at the face, it is possible to make some comparisons on the particulate distributions in diesel versus non-diesel mines.One of the more interesting results is the pattern that exists in mines that contain only diesels used for outby utility haulage. Particulate in these mines seem to be consistently heavy in the fine size ranges, perhaps being of significant concern to the industry. While no definite conclusions can be achieved from the limited data collected in this study, the data indicates that more detaile~ study of particulates in diesel mines is needed so that some idea of the particulate loadings in diesel mines can be achieved."

Jan 1, 1988

By G. R. Hopkins

According to reports received by the United States Bureau of Mines, Department of Commerce, as of January 1, 1929, there were 2,205 cracking units completed or being built in the United States, with a total daily charging capacity of 1,476,874 barrels. A similar survey of a year ago showed 2,334 units of 1,288,000 barrels total capacity. This indicates that despite a decrease in. number of units, there was a material increase in capacity. The year 1928 was, in general, an important one for the cracking branch of the industry. Gasoline consumption reached record levels, prices were higher than in 1927, and it is probable that in the late months of the year the cracking plants were operating very close to capacity.

Jan 1, 1929

By F. S. Crawford

Interesting data on electric blasting and sinking of the Montreal No. 5 shaft of the Montreal Mining Co., Montreal, Wis., were obtained during the sinking of the last 877 feet of this shaft. Several unusual features and safety practices are also to be found in the Montreal mine. The Montreal shaft was sunk 2,156 feet from August 16, 1921, to May 1, 1924, and 877 feet from October, 1927, to June, 1928. The first section of the shaft was supported with steel sets spaced 5 feet on centers; and instead of lagging the walls were covered with three-eighths of an inch of gunite where Greenstone was encountered, and where quartz-slate was found (from the surface to the 12th level) the walls were lagged with tamarack lath treated with carbolineum, a preservative.

Jan 1, 1929

By L. L. Oden

The Bureau of Mines has studied a number of processes to remove Cu from molten steel scrap with the objective of determining if any of the laboratory methods studied warranted in depth research investigations. Experimental approaches included oxidizing Cu from steel containing other metals that form stable mixed oxides with Cu (AI, Cr, Fe, Mn, Mo, and V), injecting the same metals as oxides to simplify the mechanism of complex oxide formation, partitioning Cu into alkali or alkaline earth silicate slags or oxide-moderated sulfides, and coremoving Cu and S by injecting active compounds of Ca and Mg. The most promising tests, producing nearly 0.3 pct Cu in the slag, used Ar injection of K20-moderated Na2S-FeS below the surface of molten steel containing about 0.6 pct Cu and protected by a CaO-SiOz slag; however, in depth research investigations currently are not felt to be warranted.

Jan 1, 1987

To provide a method for locating trapped miners promptly and accurately. The Approach: Develop a wireless emergency system that is intrinsically safe, compact, easy to operate, reliable, sturdy, and economical. How It Works: A (one transmitter has been developed under Bureau of Mines contracts. The transmitter weighs only a few ounces, is powered by a cap lamp battery, arid can be carried on the miner&apos;s belt. A compact loop antenna, which could either be carried by the miner or strategically located in the mine, is used to generate a magnetic field that is sensed by a mobile receiver on the surface. When needed, the antenna is deployed to form a single loop. In mines where the overburden is less than 600 feet, a loop of No. 19 wire approximately 30 feet in circumference is normally adequate. This antenna weighs less than one half pound. In deeper mines, a heavier wire and bigger loop is required; a No. 10 wire deployed around a pillar has been used.

Jan 1, 1974

By J. E. Dooley

An analytical procedure developed by the Bureau of Mines was applied to the separation and characterization of a 370° to 535° C distillate from Swan Hills (south field), Alberta, Canada, crude oil. Investigators determined the general characteristics of the crude oil by the Bureau&apos;s routine method for crude oil analysis. Suitable fractions were prepared for instrumental analyses by utilizing such techniques as isothermal and molecular distillations, chemical treatment, silica-alumina gel chromatography, and gel permeation chromatography (GK). A detailed characterization of the 370° to 535° C distillate was possible by the application of GPC-mass spectrometry correlations and nuclear magnetic resonance spectrometry. Semiquantitative data based on mass Z series distributions were determined and are shown. The data will be valuable in developing future processing techniques and in calculating yields for converting high-boiling distillates into more useful energy forms.

Jan 1, 1973

By Eugene T. Sheridan

This report presents data on individual plants of the fuel-briquet and packaged-fuel industries that were circularized by the Bureau of Mines, United States Department of the Interior, in its annual survey for 1958. Only plants that processed fuels of mineral origin were included; specifically, plants that manufactured briquets from charcoal were excluded. Fuel briquets and packaged fuel are manufactured by mixing fine-sized fuels with binders and compressing into small individual shapes. Both are used mainly for residential heating in the United States, but they differ considerably in appearance and physical characteristics. Briquets usually are produced as small, pillow-shaped forms, 2 to 4 inches in length, weighing from 2 to 4 ounces. Pack-aged fuel consists of 3-to 4-inch cubes, 6 or 8 of which are wrapped in heavy kraft paper to form a package weighing 10 to 15 pounds. Briquets are made with a water-insoluble binder and are designed for rough handling and outdoor storage, whereas packaged fuel generally is made with a water-soluble binder and must be stored indoors to prevent deterioration. Briquet plants are relatively large and usually are at mines or in dock areas where large quantities of fine-sized fuels accumulate. Packaged-fuel plants are smaller and are used chiefly by retail dealers to convert locally available coal and coke fines into a product that can be burned efficiently in residential beating equipment.

Jan 1, 1959

By H. G. Iverson

An investigation was conducted on the conditions affecting the precipitation of aluminum by autoclaving synthetic solutions containing Na2SO4, Al2(SO4)3, H2SO4, and H2O. Virtually all of the alumina could be precipitated as natroalunite (NaAl3(SO4)2 (OH)6). This product could be readily filtered and dried. Results are reported in terms of alumina precipitated in this compound and not in terms of alumina itself. Solutions of ~ 0.30, ~ 0.60, and ~ 0.80 mole/liter A1203 and various concentrations of H2SO4 and Na2S04 were investigated. The optimum time and temperature for autoclaving were 20 to 30 minutes at 200° C. The highest yields of natroalunite were obtained from solutions containing little H2SO4 and ~ 2 moles Na2SO4 per mole A1202. Acid in quantities of 0.3 to 0.5 mole/mole of alumina in solution depressed the yield to 90 percent or less. In differential thermal analysis, at 1,000° C the natroalunite precipitate decomposed without melting to yield SO, and SO2 gases, a solid composed of Na2SO4, and gamma and alpha Al203. Continued heating to 1,200° C produced No SO, and alpha A1303. Water-leaching of this product removed the Na2S04 and left a final residue of alpha A1203.

Jan 1, 1968

By d&apos, Kathleen J. Amico

THIS SUMMARY appears in Minerals Yearbook volumes I and III, which cover mineral production in the United States, its island possessions, the Canal Zone, and the Commonwealth of Puerto Rico, as well as the principal minerals imported into and exported from the United States. The several commodity and area chapters contain further details on production. A summary table comparing world and U .S. mineral production also is included. Mineral production may be measured at any of several stages of extraction and processing. The stage of measurement used in the chapter is normally what is termed ?mine output." It usually refers to minerals in the form in which they are first extracted from the ground, but customarily includes for some minerals the product of auxiliary processing operations at or near mines.

Jan 1, 1965

By F. E. Spencer

This Bureau of Mines report provides a complete mathematical description of the algorithm employed by a general multiphase chemical equilibrium program developed particularly for the purpose of studying problems in coal combustion, although the generality of the program will allow its application to any equilibrium system in which an appreciable gas phase is present. When applied to coal combustion problems, the program predicts composition and quantity of slag and unconsumed carbon phases as well as calculates accurately the composition of the gas phase including trace species such as free electrons and ions which are important for predicting electrical properties.

Jan 1, 1973