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By H. W. St. Clair

Sampling of heterogeneous mixtures of fused metals or solidified melts is subject to errors not met in sampling finely ground ores or granular materials. These errors arise largely because of the segregation of constituent metals that usually takes place during solidification. It is seldom that a random sample of a lot of metal will represent the composition of the entire lot. The problem becomes especially difficult when it is necessary to make accurate analyses for a segregated impurity present in very small amounts. This paper discusses some of the pertinent experimental observations made in selecting a method for sampling melts of aluminum and zinc containing small amounts of iron and silicon as impurities. Although this experimental study dealt only with sampling this specific combination of metals, many aspects of the study apply generally to any mixture of mol ten metals containing minor constituents that segregate rapidly during freezing of the melt.

Jan 1, 1949

By H. W. Sheffer

Technical and economic aspects of community refuse disposal systems and their effects on the environment are identified and described. Seven landfills and two incineration systems, located throughout the United States, are reviewed.

Jan 1, 1971

By G. L. Oldright, Virgil Miller

"This paper is the ninth 4 of a series on smelting in the lead blast furnace, and the fourth on modifications brought about by the introduction of richer charges.ACKNOWLEDGMENTSThe authors wish to express their appreciation to Stanley A. Easton, Frank M. Smith, and A. F. Beasley, and to their staff for the whole—hearted cooperation that made it possible to obtain the data in this publication at the Bunker Hill smelter, Kellogg, Idaho.INTRODUCTIONIn tie account written of the conditions obtaining at the tuyere zone in the blast furnaces at Tooele (R. I. 2965) the authors gave references to articles covering (1) the effect of temperature on the equilibrium 2C0 - CO2 + C, (2) experimental work that has been done on learning the gases existing at various elevations in columns of burning coke, (3) extension of this work to the tuyere zone of an iron blast furnace, and (4) the paper itself gave similar analyses of the gaseous oxides of carbon at the tuyere zone of a lead blast furnace and showed the temperatures obtaining there. There were also references in the above paper to the literature on (5) how the lead compounds likely to be present might be ex¬pected to react. A careful study of the original articles selected as references will give a good background for the present work.The following very brief recapitulation may be convenient before considering the tuyere zone in the blast furnaces at Kellogg. The ""producer gas reaction"" (1) of course goes to the left at increasingly higher rates of speed with increase of temperature. When air is blown upward through a grate and a column of hot fine coke alone, oxygen as such penetrates from some 2 to 3 inches only, under the conditions obtaining as to the amount of surface exposed per unit volume of air. When air is blown at about 20 pounds pressure through the tuyeres in the side of an iron blast furnace into a column of coarse coke (plus furnace charge) it may penetrate for 30 inches before the oxygen is entirely used, burning first largely to CO2. Within wide limits, the rate of feeding air into the furnace has practically little effect on the composition of the gases obtaining in the fuel bed of fine coke, this being true particularly of the gases leaving the bed. Some 10.5 inches above the grate the gases contained 22 per cent of CO by volume, and a little further up the CO2 had practically disappeared. This gave the familiar three zones in both the iron blast furnace and the gas producer; in order of entry of the air, in the first the oxygen burned largely to CO2, in the second the CO2 was reduced to CO, and the third the CO2 was practically absent. In the furnaces at Tooele, conditions were somewhat erratic but the first two zones were present, there being, however, no zone in which CO2 and 02 were both entirely absent."

Apr 1, 1931

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 S. H. Brooks

"IntroductionThis preliminary report deals with the effect of oxygen pressure on the ignition temperature and combustibility of oils, it is the third of a series which will present the results of an investigation being made by the Bureau of Mines, on oxygen-oil explosions. The purpose of this research is to obtain technical data that will serve as a basis for safety precautions general outline of the problem has been given in the first report (Serial 2507).The present experiments have resulted in (1) a method for determining spontaneous ignition points of oils in an atmospheric of oxygen under pressure; and (2) the determination of these ignition temperatures for three typical oils, one being an animal oil (sperm), one a vegetable oil (linseed), and one a mineral oil (""Moiloil A"").These experiments on explosibility of oil were performed in order to discover the general nature of the phenomenon, especially the order of magnitude of the temperature necessary for spontaneous explosion (120°C. and upwards) and the effect of pressure variation (negligible as regards ignition temperature but important in relation to the violence of the explosion). A continuation oftests should provide a basis for selecting the safest lubricants for high pressure compression of gases particularly air and oxygen; and should be of value when devising new specifications for lubricants, both in the government departments and the compressed-gas manufacturing industry."

Dec 1, 1923

By W. P. Haynes

To evaluate the potential use of battery-powered vehicles, the Bureau of Mines studied the performance of a battery-powered truck propelled by a 9.6 kw dc motor in considerable detail under various driving conditions. Some of the factors investigated were: Gear ratios, payload (1,468 lb maximum), road grade, stops made per mile, and charging time. With the exception of some difficulty with brush wear, operation and maintenance of the truck was generally trouble-free. On range tests carrying an 868-lb payload a distance of about 50 miles at an average speed of about 19 mph in normal driving, the Bureau's battery-powered truck averaged 1.6 to 1.9 miles per ac kwhr input. Stop-and-go tests indicated that prospects for the use of battery-powered trucks in house delivery service within city limits are good; performance of the Bureau truck was sufficiently high for that type of service. The estimated power cost of 2.65 cents per mile while making 10 stops per mile was attractively low from the standpoint of fuel costs.

Jan 1, 1967

By Jerry J. Gray

The utilization of secondary titanium was determined in a study by the Bureau of Mines, and a 10-year statistical table showing supply and distribution patterns is presented in this report. Over the total 10-year period, estimated scrap consumption is larger than estimated scrap supply. Trends from the estimated data indicate that titanium is in short supply and probably will continue to be in the future. Because of higher processing costs for recycle scrap, scrap will tend to migrate to the steel and aluminum industries and to ferrotitanium production and exports. Nonrecoverable losses of titanium metal during processing was determined to be a potential area for research.

Jan 1, 1971

By Robert J. Evans

Reclamation costs were estimated for 20 coal surface mining operations in the Appalachian and Midwestern Coal Supply Districts (these two districts were divided into three multi-State regions). The cost data were obtained through onsite observations, interviews with mining company personnel, and the authors' cost estimating procedures. The cost data are presented in terms of dollars per acre, dollars per ton of coal produced, and dollars per cubic yard of overburden moved during backfilling. The reclamation process is divided-into three cost categories: Premining planning, backfilling, and revegetation. The average total reclamation costs for the three regions are $2.77 per ton of coal produced and $8,168 per acre. As the result of comparisons of reclamation costs by region, by mining method, by slope, and by size of operation, the most important reclamation cost difference is between area mining methods ($1.73 per ton) and contour mining methods ($3.81 per ton). The Federal Bureau of Mines conducted this study to determine as accurately as possible the actual costs involved with the reclamation of coal surface mined land done in conjunction with active mining operations.

Jan 1, 1975

By W. C. Holliman

This second of a series of reports on the characteristics of commercial aviation gasolines presents inspection test data furni8hed on their products by 15 manufacturers of commercial grades of aviation gasoline and special data obtained in Bureau of Mines laboratories on samples of these gasolines. Data on 18 grade-80, 20 grade-91/98, 20 grade-100/130, and 9 grade-115/145 aviation fuels are presented. These gasolines represent July 1947 production.

Jan 1, 1948

By W. E. Webb

This report describes a method the Bureau of Mines devised for measuring the dielectric constant and loss tangent of low-loss minerals at microwave frequencies. Determina-tion of these properties makes it possible to predict the effects of using microwave heating in potential mineral processing applications. The method uses a test cell and radio-frequency (RF) impedance analyzer with automated data acquisition and analysis. In this initial phase of microwave heating research, the Bureau measured dielectric constants and loss tangents at frequencies between 100 MHz and 1 GHz. The objective was to establish a reliable data base for use in predicting the effects of microwave heating on minerals. Comparison with previously measured data showed the Bureau's measurement method to be accurate to within ± 3 pct. This report describes the method and discusses the preliminary results of the Bureau's investigations. Typical comparative data are included.

Jan 1, 1986

By T. E. Swigart

In the production of oil end gas, engineering methods have been applied less than in any other branch of the oil industry. While refineries, gasoline plants, pipe-line and other transportation systems, and even drilling wells to a great extent, take advantage of engineering skill, the tendency has been to assume that the handling of producing wells is merely a mechanical and routine matter. At present few companies employ engineers to study oil and gas production methods with a view of increasing the general efficiency of recovery, but in vie, of the advancement in other lines of the petroleum industry by the application of engineering principles, does it not seem likely that the production branch may benefit also by engineering studies? Engineering applied to the handling of producing wells falls under two general headings, - first, the efficient handling of wells from the time of their inception in order to obtain the greatest possible ultimate production, and, second, the rehabilitation of old properties that have been handled carelessly in their early lives. To date, the engineering work that has been done on oil production problems falls mostly in the second class. For example, the use of vacuum and the application of compressed air have proved successful in some instances in stimulating wells of low gas pressure. These methods are costly to apply and are adapted to small wells in which the gas is almost exhausted, or in which the original gas pressure is negligible. The experiments described in this paper fall under the first heading, as they were made with an idea of learning toe probable extent to which the gas production of an oil well can be curtailed while gas in the sand is still plentiful, and thus saved for doing work during the later period of a well's life. Because of the scope of the experiments, this paper does not include a discussion of back pressure on flowing wells or for purposes other than cutting down the gas produced with each barrel of oil.

Jan 1, 1922

By Arnold P. Pipilen

In a study of the principal factors affecting the transport of coal-water mixtures through a centrifugal pump and a pipeline, the interrelation between solids concentration, velocity, and pressure drop was established for a bituminous lump coal (minus 2 inch) in concentrations up to 48 weight-percent. An optimum concentration was found to exist for maximum capacity of a given pipe-line, and for minimum energy requirements per ton of coal. Coal size degradation by particle fracture took place in the pump; abrasion and attrition to form fines took place in both pump and line. A novel system of studying flow of solid-liquid mixtures in pipelines by the determination of relative sound intensities was developed.

Jan 1, 1966

By L. A. Morley

Volume III of the final report examines the indication versus interruption procedures used on motion-drive power equipment, with emphasis on surface excavators. The report begins with a review of the electromechanical acid conversion used with the Ward-Leonard control system. Protection criteria for the drive-system components are then discussed. Fault sources and fault calculations for both the ac supply source and dc power loop are introduced to assist in discussing indication and interruption procedures. The subject is then expanded to examine the dynamic process of the machine and determine the effects of fault current and position of the machine to allow for an orderly shutdown. With this analysis, possible indication an interruption procedures are given for the four-quadrant duty cycle of excavators. The report concludes by introducing other mining operations that utilize similar motion-drive systems and also static (solid-state) drives and recommends further research in these areas, as well as a more detailed examination of the dynamic fault analysis for excavators.

Jan 1, 1982

By C. W. Van Noy

The procedure suggested in this report is intended for the use of engineers, esters, accountants, etc., in estimating the cost of chemical-type operations. It is intended to over operating costs, not investment costs, as the latter have been covered numerous other publications. However, as capital investment costs are reflected to a high degree in operating costs, it is important to point out that accuracy of investment costs is highly essential. Therefore, all factors that might be included under plant -capital costs should be considered, such as requirements of shops, employees' housing, etc. The procedure is designed primarily for use in types of chemical oper¬ations, such as the production of synthetic liquid fuels, anhydrous ammonia, and others of like or similar nature. Yet, no attempt has been made to cover the entire chemical industry.

Jan 1, 1949

By V. T. Dow

In April 1957 the Bureau of Mines instituted a reconnaissance of titanium-and zirconium-bearing heavy sandstone deposits in the Four-State area of Utah, Wyoming, New Mexico, and Colorado. This report summarizes the study. Eighty-two deposits or groups of deposits, containing an estimated 27,920,000 tons of titaniferous sandstone, were examined in the Four-State area; 16 in southern Utah, 19 in Wyoming, 33 in New Mexico, and 14 in southwestern Colorado. The 16 deposits examined in Utah contain an estimated 1,043,000 tons with an average grade of 17.98 percent TiO2, 5.67 percent ZrO2, 20.98 percent Fe, and 0.09 percent equivalent Th02. The 19 deposits investigated in Wyoming are estimated to contain 21,873,000 tons of titaniferous sandstone having a weighted grade of 5.22 percent 702, 0.55 percent ZrO2, 24.8 percent Fe, and 0.01 percent equivalent Th02.

Jan 1, 1961

By David C. Oyler

The U.S. Bureau of Mines and the United States Steel Corporation evaluated the progress of methane drainage at the Oak Grove, AL, degasification pattern. Coalbed pressures were monitored between December 1981 and November 1985. Formation pressures, in the lower bench of the Mary Lee Coalbed, were reduced from 400 lbf/in2(ga) in 1977 to 50 lbf/in2(ga) in November 1985. Gas contents of coal cores obtained from monitor wells were compared with coalbed gas contents measured in 1976. Data indicated a 48- to 56-pct reduction within the pattern and a 29-pct reduction at a point 500 ft outside the pattern. The effect of the advance of a section of the Oak Grove Mine on changes in gas and water production rates in the pattern was evaluated. Gas production increases were noted in 12 wells; water production decreases were noted in 6. The times of initial influence indicate the presence of a zone of high permeability within the pattern. This zone correlates well in orientation and location with a fracture zone mined through at the mine. The existence of such fracture zones could have a significant effect on productivity of individual coalbed methane wells.

Jan 1, 1989

By Z. Zhiqun, V. A. Marple, B. Y. H. Liu

"IntroductionIt is commonly understood that aerosol particles may be injurious to human health if they are of a size that enables them to enter the respiratory tract. Coal Workers' Pneumoconiosis (CWP) is one disease known to be caused by coal mining related particles.The location in the respiratory tract where the particles are deposited is primarily a function of the equivalent aerodynamic diameter (EAD) of the particle. The equivalent aerodynamic diameter is the diameter of a spherical particle with a density of 1.0 gm/cm3 with the same falling speed as the particle in question. For a spherical particle the calculation is rather simple in that the equivalent aerodynamic diameter is simply the diameter of the particle in question multiplied by the square root of the density of the particle. For irregularly shaped particles, such as coal particles, there is no simple way to make the EAD calculation. For example, Figure 1 is only one of an infinite variety of particle shapes that can be found in practice and the aerodynamic size of this particle and, therefore, its deposition location in the respiratory tract would be nearly impos-sible to estimate accurately.The normal method for determining the aerodynamic diameter of particles has been to experimentally measure the size of the particles in a settling chamber or with an inertial classifier such as an impactor, cyclone or a centrifuge, since inertial classifiers have the property of classifying the particles according to their aerodynamic diameters."") However, these devices can only give limited information on the EAD of a single particle with a specific shape. Impactors and cyclones, for example, collect particles in size ranges and not at a specific size, so the determination of the EAD of a specific particle is not possible. A centrifuge, on the other hand, can measure the EAD of a specific particle but the equipment is costly and procedure laborious, and it may not be possible to disperse a particle of a specific shape into the centrifuge. The centrifuge can be used to determine the EAD of clusters of spheres in various arrays, but introducing particles of a specific irregular shape may not be feasible. Furthermore, the EAD is a function of the orientation of an irregularly shaped particle and the orientation of a particle in an inertial classifier is unknown. The orientation may also vary as the particle passes through the classifier.Because of the difficulty in determining the EAD of an irregularly shaped particle, we have undertaken a program to apply theoretical numerical methods to calculate the EAD of any shape particle. In our laboratory we have, for some time, been using numerical methods to determine the flow field of air within instruments such as impactors, (2) inlets, (3) and virtual impactors (4) Recently, this technique has been expanded into the three-dimensional regime, and the flow fields and particle motion characteristics within cyclones (5) and glove boxes have been studied. We have now begun to use these numerical three-dimensional flow programs to study the flow field around irregularly shaped particles to determine their drag coefficients, falling speed, and thus, their EAD."

Mar 1, 1989

By B. W. Gandrud

[The Bureau of Mines is conducting an extensive investigation of coal preparation in the Alabama coal fields in cooperation with the University of Alabama and coal-mine operators. In this investigation the drainage characteristics of typical coals from the Warrior and Cahaba n fields were studied. Tire main purposes of this study has been to evaluate no nearly as possible relative influences of certain factors on rate of drainage and to determine whether the drainage characteristics of coals from different beds or from different mines on the soma bed differ materially. A further objective was the development of a laboratory drainage test that would predict approximately the rate at which any coal will drain after having been loaded into a railroad car in a saturated condition. The study has been confined to samples of slack coals - that is, coals from which none of the fine sizes have been removed. The samples ranged in upper size limits from 7/16 inch to 3 inches. It did not seem necessary to study nut and egg sizes, that is, sizes from which the fine coal has been removed by screening, as these lose water so rapidly by natural drainage that they present no serious problem in dewatering after treatment in a washer. The significance of drainage characteristics of Alabama coals is apparent in view of the fact that not less than 70 percent of Alabama?s total coal product is subjected to wet washing before being materials.]

Jan 1, 1941

By Stephen D. Cramer

A nondestructive procedure for measuring electrodeposit porosity has been developed which records the location and number of deposit defects including pores, pits, and voids. The procedure involves the passage of an X-ray beam through the deposit-substrate system onto suitable film. The defects are recorded as images on the film. Variables studied included intensity and spectra of the X-ray beam, composition and thickness of deposit and substrate, film type and developing procedure, and limits for detecting defects. At an X-ray tube voltage of 40 kv, pores several mils thick were easily detected in copper-nickel specimens more than 20 mils thick. To illustrate the utility of the procedure, the effect of substrate oxidation and of current density on electrodeposit porosity was briefly studied.

Jan 1, 1970

By Arnold B. Hubbard

This report presents a hydrogenolysis study undertaken to obtain information on the constitution of the kerogen or organic material in Colorado oil shale and to determine some of the properties of the hydrogenolysis products. The high yield of hydrogenolysis products was separated, so far as possible, into type compounds; a number were identified. The results thus obtained were used as a basis for proposing the possible existence of certain structures in kerogen. To the authors' knowledge, few or no hydrogenolysis studies have been made of Colorado oil-shale kerogen by others. However, this method has been used in studying the constitution of coal. In general, the coal studies involved treating pulverized coal at different temperatures and hydrogen pressures with different catalysts. In some instances different solvents were used during the treatments.

Jan 1, 1959