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By B. J. Dalton

The Bureau of Mines Helium Research Center has as a long-range objective the development of an equation of state for helium that will allow all of the thermodynamic properties to be calculated within the accuracy with which they are known. If this objective is to be realized, a method of calculation must be known. This report gives the principles of the method we use in such problems. A computer program was developed for predicting these properties, including those at the critical point, that is perfectly general and applicable to any equation of state. To demonstrate the efficacy of our method, this computer program was used to evaluate thermodynamic properties of a Redlich-Kwong fluid in the two-phase region. Expressions for calculating various thermodynamic functions specific for this particular equation of state are derived. Numerical values are tabulated and graphs are presented for all functions calculated. It is shown that for a Redlich-Kwong fluid there are finite discontinuities in (1) the second temperature derivative of the Gibbs free energy or chemical potential at the critical point, (2) the second derivative of the vapor pressure curve with regard to the temperature on passing through the critical point, and (3) the measured heat capacity at constant volume on passing through the critical temperature when the calorimeter is filled to the critical density. It is also shown that the heat of vaporization is infinite for a Redlich-Kwong fluid at absolute zero.

Jan 1, 1969

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

"The electrostatic charge on spray droplets of ionic surfactant solutions and coal particles was measured and the results were correlated with the dust collection efficiency. When various surfactant were added, the magnitude of the droplet charge increased significantly and it was observed to be a function of surfactant type and concentration. The concentration of maximum droplet charge coincided with surfactant concentration where maximum collection efficiency was observed for these surfactants. Particles of coal also carried substantial amount of charge magnitude of which seemed to be a function of coal rank.Based on the results presented in this paper, it was concluded that ionic surfactant primarily act as a strong electrostatic charge inducer for droplets. Due to interactions between these highly charged droplets and naturally charged particles, the efficiency of droplet-particle collisions play a primary role when compared to the wetting and engulfment phenomenon which could only follow a successful collision. INTRODUCTIONWater spray are widely used to suppress airborne dust in mine atmospheres (Walton and Woolcock, 1960; Kobrick, 1970; Hamilton, 1974; Jayaraman et al., 1986). Several investigators have considered the use of surfactants to enhance the effectiveness of water sprays especially for difficult to wet particles such as those of coal (Glanville and Wightman, 1979). The capture of dust particles by water droplets involves droplet-particle collisions, adhesion of particles to droplets, and engulfment of particles into droplets. Surfactants affect these sub processes through their influence on droplet charge, surface tension, and wetting. The last two mechanism have been thoroughly studied in recent years (Walker et al., 1952; Cohen and Rosen, 1981; Glenville and Haley, 1982; Chander et al., 1988; 1991). However, little attention has been paid to the role of electrical charge on particles and droplets on the collision and adhesion of spray droplets and dust particles."

Nov 1, 1995

By M. M. Barr

Rapid expansion of the titanium-metal industry focused attention upon ilmenite as a possible substitute for the more expensive and less abundant rutile in producing titanium tetrachloride. Most of the rutile available for this use is imported. Preliminary studies were undertaken to determine the chlorination characteristics of high-titanium slags produced by electric-arc furnace smelting of alluvial Idaho ilmenite at the Federal Bureau of Mines Northwest Electrodevelopment Experiment Station, Albany, Oreg. Low silicon, calcium, and aluminum contents of the slags enhanced their potential value for chlorination.

Jan 1, 1958

By A. U. Miller

Since coal -mining records have been kept , reports of all mining States show that each year the lives of many workers have been sacrificed in the production of coal , and Illinois has contributed its share , Illinois reports for the 50 years 1882 to 1932 , inclusive , show that 6,673 men were killed -- 6,121 underground , 340 in the shaft , and 212 on the surface . Of the fatalities underground , 3,116 were caused by falls of roof or sides , 1,111 by haulage , 630 by explosives , 577 by gas explosions , 139 by electricity, and 548 by other causes ; 166 of the shaft fatalities were caused by falling down the shaft , 143 by the cage , and 31 by other causes ; 108 of the surface fatalities were caused by railroad cars , 46 by machinery , and 58 by other causes . Most of those engaged in mining are still of the opinion that it is an extremely hazardous occupation and that it is practically impossible to operate without accidents ; however , students of safety in mining now believe that with the proper attention to accident prevention mining may be conducted with little , if any , greater accident rate than that of other supposedly hazardous industries . There is no mystery connected with accidents in mining ; reports show that the majority are due to two main causes , falls of roof and sides and haulage . Mining companies in Illinois , as well as in other States , have proved in the past few years that the hazards of mining , like those of other industries , can be controlled to a large extent and the mines operated with few if any accidents , provided a great enough effort is made by employer and worker . Although the past accident rate of Illinois may compare favorably with that of other mining States it is higher than it should be ; the fact that 6,673 men (an average of 133.46 per year) were killed in and around the mines of the State between 1882- and 1932 indicates that accident prevention should receive more consideration in the future than in the past .

Nov 1, 1934

By L. B. Berger

"INTRODUCTION Accurate determination of carbon monoxide in concentrations ranging from 0.2 to about 0.5 percent by volume is troublesome, because such concentrations are too high for some analytical methods and too low for others. Methods that are sensitive to concentrations of carbon monoxide considerably less than 0.2 percent are approaching their upper limit of usefulness when applied to the analysis of samples containing 0.2 percent or more of carbon monoxide, and it may be necessary to resort to dilution of the sample with a known proportion of air, or otherwise modifying the analytical technique, to obtain satisfactory results. Such methods include the determination of carbon monoxide by reduction of heated iodine pentoxide 3/4/5/ by the ""Pyrotannic acid"" method 6/ and by the so-called ""phosphomolybdic acid"" method. 7/ The use of conventional gas-analysis equipment, such as the Orsat type, in the determination of carbon monoxide in concentrations ranging from 0.2 to 0.5 percent is not desirable, as possible analytical errors may be of about the same magnitude, thus producing results of little quantitative value.For several years prior to this publication, the Gas Analysis Laboratory of the Health Division of the Bureau of Mines has used a modification of the Haldane type 8/9/10/ gas-analysis apparatus for the determination, by absorption in a chemical reagent, of carbon monoxide in low concentrations that are not readily determined by other methods. The method is applicable also to the determination of higher concentrations. As the procedure has proved successful and has been adopted by others, this report was prepared to describe the method and to present results of analyses obtained with it."

Nov 1, 1947

By H. Kenworthy

[Experimental studies were made to develop a laboratory technique for direct removal of cadmium and germanium from sphalerite concentrates. Cadmium- and germanium-bearing concentrates from the Illinois-Kentucky fluorspar field were sound to be, amenable to an inert atmosphere fuming process for removing these two moats in the form of gaseous sulfides. Treating the condensed fume by pyrometallurgical methods upgraded the material end provided a means of partly separating the constituents. Cadmium was concentrated about 35:1 arid germanium about 300:1. The extractive investigations were supplemented by vapor-pressure studies on the sulfides of germanium to obtain fundamental data for larger scale laboratory conditioning and control when treating the zinc concentrates. Vapor-pressure curves were developed for synthesized monosulfide and disulfide The results of these- investigations indicate the possibility of significantly increasing the recovery of cadmium from zinc concentrates. Comparison with present recovery of germanium cannot be made, since commercial recovery data arc not available.]

Jan 1, 1956

By D. R. Mathews

Electrorefined vanadium was evaluated with respect to tensile properties and the effects of interstitial contaminants in the temperature range of 77° to 273° K. The yield strength of 18,500 psi and hardness of 63 diamond pyra-mid hardness (DPH) of electrorefined vanadium are approximately equal to that of iodide crystal bar vanadium. The ductile-brittle transition temperature was found to be below 77° K, but with 0.175 weight-percent oxygen or 0.10 weight-percent nitrogen, it increased to between 123° and 190° K. With carbon content up to 0.11 weight-percent, the transition temperature remained below 77° K. The yield strength of the interstitial-containing alloys can be expressed by: au = 7.5 + 480 (pct N) + 290 (pct 0) + 280 (pct C), where au is the upper yield stress in 1,000 psi at 273° K. Profuse deformation twinning occurred in the alloys tested at 77° K. However, twinning could be suppressed by dissolved oxygen or nitrogen in excess of 0.15 and 0.086 weight-percent, respectively. Carbon, even though present in excess of the solubility limit, did not affect twinning.

Jan 1, 1965

By R. R. Sayars

"Carbon monoxide is a gas slightly lighter than air, with which it diffuses readily to make a homogeneous mixture. It will burn and has a wide explosive range, that is, an explosion is possible when the air contains from 15 to 73 per cent of the gas3. This explosive range is about the same as that for hydrogen and over nine times As Tide as that for marsh gas (methane). Like air, it has neither color nor taste and has no odor in concentrations usually encountered, therefore it cannot be detected by the ordinary senses with which men are endowed. It is produced by burning carbon containing fuels, no coal, wood, gasoline, etc., whenever not enough air or oxygen is supplied to burn and oxidize the fuel completely.The human race has probably been exposed to this gas since men first began using fires in confined or sheltered places. The poisoning as usually encountered is an acute condition resulting from breathing atmospheres con¬taining this gas. A number of eases described in the ancient literature Indicate that carbon monoxide was a frequent cause of death by accident, suicide and is a means of punishment or torture. A quotation by Lewin from Aristotle who lived in 384-322 B.C., states that ""animals collapse from harmful odors as men gets a severe headache and often dies through charcoal vapors"". The Roman knew that smoke was poisonous, and used the greenest most smoke-producing wood to put persons to death. The occurrence of carbon monoxide increased in frequency through the years until at the present time it is found in the home as well as in many industries. The following table gives the approximate percentage of carbon monoxide found in gases from various sources of poisoning.4"

Apr 1, 1924

By L. B. Berger

Studies showing the effect of mixing hot exhaust gases with tie intake air of a four-stroke-cycle Diesel engine are described. The results indicate a marked increase in carbon monoxide in tip exhaust gases, a decrease in oxides of nitrogen, and no significant effect on aldehydes. The increase in carbon monoxide was greater at higher fuel-air ratios and was caused partly by the increase in fuel-air ratio end partly by the decrease in oxygen concentration resulting when exhaust has was added. The application of these results to the use of Diesel engines underground is considered.

Jan 1, 1940

By P. L. Woolf

Seven evaluation tests with blast furnace iron bearing burden materials are described. The effects of pellet strength, fines in the burden, decreasing slag volume, pellet size, eliminating stone with superfluxed sinter, and eliminating stone by prefluxing the pellets were determined. Fluxed pellets and fluxed sinter made with the same ore fines were compared. The tests were conducted under cooperative agreements between the Bureau of Mines and North American steel companies. The objectives were to improve blast furnace practice, expand and develop understanding of the operation and theory, quantify the effects of changes, and explore the limitations of operability. This work was part of an extensive program of blast furnace research in experimental blast furnaces at Bruceton, PA conducted in the years 1958 to 1967.

Jan 1, 1984

By A. G. Starliper, H. Kenworthy

A procedure was developed for the separation of lead and sulfur in industrial concentrates of galena by a combination of chlorination and fused - salt electrolysis . Galena could not be satisfactorily electrolyzed in the various media tried ; however , when it was treated with chlorine the resulting lead chloride could be effectively separated electrically into lead and chlorine . An apparatus was designed and constructed to chlorinate galena and to volatilize simultaneously most of the chloridized impurities . By electrolyzing the chlorinated concentrate , a high percentage of lead was recovered . Anodic chlorine was drawn from the cell and was used to chlorinate new feed . In many runs , the recovered metal analyzed from 99.8 to 99.9 percent lead . Lead was also distributed as a chloride in the bath , and a small portion was in the volatile fraction produced during the chlorination step . During a tinuous operation , only 0.1 percent of the total lead was discarded ; 99.9 percent was accounted for in the metal , electrolytic bath , and washed or leached chlorination condensate which was essentially lead chloride . About 95 percent of the sulfur from the galena was recovered as a byproduct of over 90 - percent grade .

Jan 1, 1964

By G. Richards Gwinn

"Mica" is a group name for a number of orthosilicates of aluminum with magnesium, ferrous iron, and the alkalies. They are characterized by their high reflection and a basal cleavage so well developed that they can be split into exceedingly thin laminae, which are more or less tough, elastic, and transparent, according to variety. Barium, manganese, lithium, chromium, titanium, boron, and ferric iron occur in same varieties. Eight distinct species of true mica, which appear in the following table, are recognized by mineralogists, but only the first five are of commercial importance. [Species General Formula Muscovite H2KA13 (SiO4)3 Phlogopite [H,K, (MgF)]) Mg3A1 (Si04)3 Biotite (H,K)2(Mg,Fe)2(Al)Fe)2 (S104)3 Lepidolite K,Li Al(OH,F)2 Al (5103)3 Ros coalite H8K(Mg,Fe) (A1,V)4 (S103)12 Paragonite H2NaAl3(S104)3 Zinnwaldite (K)Li)3 FeAl3 Si5016(OH,F)2 Lepidomelene HK2F3IIIFe6III A13 (S104)9]

Jan 1, 1951

By L. H. Adami

This paper reports the results of solution calorimetry conducted to obtain the heats of formation of crystalline FeS04?6.952H20 and FeS04?1.008H20, from. which values were derived for the stoichiometric compounds FeS04?H20 and FeS04?H20. Also included are derived values of the free energies of formation and dehydration. This work was undertaken primarily to fill a need for data for pure, easily obtainable ferrous compounds that are suitable for use as calorimetric intermediates, The ferrous sulfate hydrates meet the essential requirements for this use.

Jan 1, 1963

By Donna L. Anderson

This U.S. Bureau of Mines report discusses the status of a laser-based guidance system to provide position and heading feedback and closed-loop control of tramming maneuvers for a continuous mining machine. The system has been developed and tested at the Bureau, and is now being prepared for underground experiments. The system hardware includes laser scanners, a sensor communication network, and host computer hardware. The system software includes a position and heading computation module and a tram control module. The description of the software includes discussions of laser data acquisition, error compensation methods, position and heading determination, safety checking for continuous miner tramming, and closed-loop tram control. The accuracy of the laser scanner's data, the reliability of the lasers in a dusty environment, and the system's accuracy on tracking the position and heading of the continuous mining machine are shown in the results of experiments performed at the Bureau. Conclusions are stated based on these experimental results, and further work to improve the system performance and prepare for underground testing is discussed.

Jan 1, 1990

In 2007, a total of 4,639 stone mining operations reported employment to the Mine Safety and Health Administration (MSHA).1 Stone mines comprised 31.2% of all mining operations. ? Mines producing the primary commodity of limestone (crushed and broken) comprised the largest number of operations (n=2,051; 44.2%). ? Stone mining operations were located in all states and territories except Delaware and North Dakota. ? Pennsylvania had the most stone mines (n=373; 8.0%), followed by Texas (n=352; 7.6%).

Aug 1, 2009

By B. R. Mohal, F. F. Aplan, S. Chander

"The wetting behavior of coal has been determined in the presence of nonyl and octyl series of nonionic surfactants containing polyethoxy groups of different sizes. The wetting behavior was determined by a modified Walker technique and contact angle measurements. The results show that the wetting rate of coal varies with coal rank, structure of the hydrocarbon chain and number of ethoxy groups in the hydrophilic group of the surfactant. A close relationship has been observed between the wetting rates and the short-time advancing contact angles.INTRODUCTIONNonionic surfactants are used in many applications to improve wettability of solids. They can be used as dispersing agents [ 1 ] or dust suppressants [ 2-5] and to control the flotation, flocculation, filtration and, flowability of particulates. This study was undertaken to study the effect of a series of nonionic surfactants on the wetting behavior of coal. Two series of surfactants, namely, ethoxylated nonyl and octyl phenols were used. The nonyl phenol series con tains a linear hydrocarbon chain containing nine carbon atoms (CH3 ( CH2 )8-C6H4- ( OC2H4 ) n, where n is the number of ethoxy groups) . The octyl phenol series contains a branched hydrocarbon chain containing eight' carbon atoms ( ( CH3 ) 3CCH2C ( CH3) 2-C6H4- ( OC2H4 ) n ).Initial wetting rates — modified Walker techniqueWalker et al. [ 6 ] developed a sink test to determine the wettability of coal particles. In this technique, coal particles are dropped individually onto the surface of surfactant solutions of different concentrations, and the most dilute concentration in which coal would sink ""instantaneously"" is determine& This technique is a variation of a procedure initially developed by Draves and Clarkson [ 7 ] to determine the effect of surfactants on wettability of cotton fibers."

Jan 1, 1989

By Alan R. Buehler

In 1986, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied part of the 256,430-acre Alvord Desert and part of the 22,240-acre East Alvord Wilderness Study Area (OR-002-074 and OR-002-073A, respectively), in order to evaluate their identified mineral resources. The study areas are located in Harney and Malheur Counties, OR, about 25 mi northeast of the small village of Fields. There are no mines, prospects, or identified mineral resources inside the study areas. Basalt flows within the study areas contain chalcedony-lined vugs and banded agate which may be of interest to rock hounds. An ignimbrite flow contains perlitic material, but crystalline contaminants make it unsuitable for commercial uses. Lacustrine (lake) sediments contain diatomite and clays, and evaporite crusts contain boron too low grade to profitably mine. Small quantities of common opal and petrified wood occur which might be of possible interest to rock hounds. Some of the petrified wood is black, free of fractures, and polishes well; it may be suitable as backing material for soft, thin, and brittle gemstones, such as precious opal. The lacustrine sediments also contain black, fetid layers which have above background, but economically insignificant concentrations of zinc, cobalt, nickel, barium, iron, manganese, aluminum, and potassium. Large quantities of fine-grained dune sands within the study areas are too far from markets for economic consideration. Ephemeral streams in the study areas contain small amounts of placer gold of no economic interest. The western portions of both study areas are reported to have moderate favorability for occurrences of natural gas, and both study areas are reported to have high favorability for the occurrence of geothermal resources. As of December 1986, oil and gas leases covered 3,100 acres in the study areas.

Jan 1, 1987

By R. W. Hiteshue, C. O. Hawk, H. H. Ginsberg, M. D. Schlesinger

The Bureau of Mines studied single - step catalytic vapor - phase hydrogenation of oils derived from coal and oil shale . Treatment of middle oil , from hydrogenation of bituminous coal , gave good yields of gasoline with a German - made molybdenum- zinc - chromium catalyst . The Bureau also achieved good results with duplicates of this catalyst made from domestic raw materials . In one set of experiments with the German catalyst , 38 to 52 wt pct of feed was converted to gasoline . The total liquid product was 91 to 98 wt pct of the feed . Not all this gasoline can be claimed as production , however , because about 20 pct of the feed was in the gasoline range , and part of it undoubtedly survived the hydrocracking treatment . Hydrogenation of crude shale oil in the presence of cobalt molybdate catalyst produced a total liquid product of 89 wt pct of feed . The hydrogenation converted 27 wt pct of feed to gasoline and 44 wt pct of feed to diesel fuel . The remaining liquid product , 18 wt pct of feed , was residue boiling above diesel fuel . The gasoline was of poor quality , with an octane number of 39.1 . The overall product seemed a suitable feed stock for a conventional refining operation . Coker distillate hydrogenation , using a cobalt molybdate catalyst , gave a total liquid product of 97 vol pct of feed ; of this product 60 vol pct was jet fuel and 40 vol pct was diesel fuel . High nitrogen and sulfur in all three of these raw materials severely poison the usual refining catalysts . Thus , the common objective in these

Jan 1, 1964

By J. E. Geier

This Bureau of Mines report reviews hypotheses for the mechanism by which water jets reduce the specific energy of cutting for drag bits. Several of these hypotheses are shown to be inconsistent with published evidence and new observations. The notion of a limiting cutting speed, above which water jets would be incapable of rendering assistance, is shown to be improbable. The hypothesis that seems most plausible is that specific energy reductions are mainly due to the erosion of crushed materials from in front of the bit. This hypothesis leads to a prediction that, for a given rock type and jet-bit configuration at a constant depth of cut, the reduction in bit forces should be a function of dM/dx, the jet energy spent per unit length of cut. This dependence upon dW/dx is shown to be consistent with other workers? results.

Jan 1, 1987

By T. T. Read, T. L. Joseph, F. H. Royster

In a preliminary study of the beneficiation of iron ores conducted by the Bureau of Mines, one of the authors (T. T. Read) found it necessary to ascertain, if possible, how much effect a decrease in the silica content of an iron ore has upon the cost of making pig iron from the ore. In the beneficiation of iron ores the most important impurity to be removed is usually silica, and the amount that can be expended on a beneficiation process to reduce the silica content of the ore is obviously determined by the amount of increase in the value of the ore after beneficiation. The price that can actually be obtained for a beneficiated ore is, of course, a matter of negotiation between the seller and the buyer, but since the relative value of different grades of iron ore must be chiefly based upon the cost of making pig iron from them, an approximation as to the effect which decrease in the silica content of ore has upon the cost of snaking pig iron is an important guide in estimating what probable average gain will result from subjecting an ore to a beneficiation process. A search of the literature failed to reveal any detailed statement on this important topic, but fortunately the data are at hand to permit making an approximate calculation of the probable effect. For the purpose of the calculation assume three iron ores with the following composition (natural):

Jan 1, 1924