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By ALICE V. Petar

Thallium is one of the rare metals that has come into commercial use within recent years . Its comparative scarcity , combined with a resemblance to the common metal lead , have retarded the development of uses for thallium . Although production is still measured in pounds rather than in tons , it is now finding application in a number of fields . Perhaps the earliest commercial use of thallium was as a constituent of optical glass of higher refractive power than similar glasses containing lead . One of the later applications to attract attention was the use of the oxysulphide in a sensitive electrical device similar to the selenium cell . The " Thalofide " cell , which was patented in 1919 , constituted for a time the most important outlet for thallium. During the next few years the limited use of thallium and its salts in other fields was insufficient to absorb an annual production of a few hundred pounds , and the price dropped from $ 16 or $18 per pound in 1922 to $ 5 per pound in 1924 . Beginning in 1925 several new uses were developed , especially as a poison for rodents and ants , and as a result the demand for thallium increased sufficiently to cause a recovery in price to the present level of from $12 to $15 per pound .

Jun 1, 1931

By E. J. HOFFMAN, J. c. W. FRAZER

The apparatus and methods described in the following pages were devised and used by the writers in connection with certain investiga- tions of the technologic branch of the United States Geological Sur- vey, especially those bearing on the improvement of furnace condi- tions and on efficiency in the use of fuel. The Bureau of Mines, which has charge of such analyses and tests of fuels as were formerly made by the technologic branch of the Sur- vey, is using the same apparatus and methods in connection with similar investigations that are being carried on at the testing plant of the bureau at Pittsburg, Pa. The furnace conditions prevailing both in small plants and in large industrial establishments in this country are frequently far from satisfactory. If such conditions are to be improved, they must be more thoroughly understood, and means must be found to insure complete combustion of the fuel, and yet to permit operation with such an excess of air as will result in the greatest efficiency. In this work the services of the chemist are indispensable. A very important problem is the determination of the small percentage of unburned combustible matter that escapes from the furnace in the flue gases. Under ordinary circumstances so little as 0.1 per cent of unburned combustible matter in a furnace gas is equivalent to about 1 per cent of the fuel used; and for the determination of such small percentages of gas more accurate and refined methods are required than have ordinarily been available heretofore. It is the purpose of this paper to describe some apparatus and methods which have proved satisfactory to those engaged in the chemical work of the investigations mentioned. While these methods and apparatus have been designed more particularly with regard to analysis of furnace gases, their use is by no means limited to that purpose. The reader will readily see their applicability to other uses in which the sampling and analysis of gases are involved.

Jan 1, 1911

By T. A. Henrie, E. K. Kleespies

Electrolytic studies were conducted to determine the transfer rates of the alloying constituents from molten titanium anodes to solid titanium cathodes in molten salt systems . The metals , nickel , tin , copper , bismuth , and manganese , were selected on the basis of thermodynamic data and the melting point of the alloy system . The transfer of nickel , tin , and bismuth was very low . The content of these elements in the cathode was in the range of less than 0.01 to 0.001 percent . The copper transfer was 0.6 to 0.8 weight - percent in electrolytes containing titanium chlorides and 0.12 weight - percent in titanium fluoride salt systems . The manganese transferred at rates comparable to that of titanium . Highpurity titanium and titanium- manganese alloys of uniform composition were produced by electrorefining molten titanium alloys in chloride electrolytes . Comparisons are made between the calculated and the actual quantities of metal transfer .

Jan 1, 1964

By R. Hogg, T. F. Dumm

"It is generally agreed that dust characteristics play a role in the development of Coal Workers' Pneumoconiosis (CWP). Unfortunately, there is a serious lack of information on what the characteristics of mine dust actually are and how they vary among different mining regions, coal seams, etc. This paucity of data can generally be attributed to the serious problems encountered in collecting sufficiently large quantities of dust for conventional analytical procedures.Personal samplers are widely used in coal mines for regulatory and enforcement purposes. Generally, these provide information only on the total (respirable) dust loading in the mine atmosphere and on the mineral matter (primarily quartz) content of the respirable dust. A procedure has been developed by which samples collected with a slightly modified personal sampler can be analyzed for particle size distribution, total mineral matter content and elemental composition, in addition to the standard mass and quartz measurements. These analyses could readily be performed on a routine basis. Shape analysis by Scanning Electron Microscope (SEM) could easily be included if appropriate shape criteria are established. Extension of the procedure to include the determination of complete size/specific gravity (composition) distributions is quite straightforward provided sufficiently large samples (at least 10 mg) can be collected. Typical sample sizes for a personal sampler carried by a miner for one shift range from about 0.5 to 2 mg.The basic procedure was developed and evaluated using synthetic mine dust prepared in the laboratory. Field tests in three working mines in Pennsylvania and West Virginia have confirmed the applicability of the approach to the real world. Particle size distribution measurements on mine dust collected in the modified personal sampler were found to agree closely with the results of simultaneous in situ measurements obtained using cascade impactors."

Mar 1, 1989

By J. A. Eisele

The Bureau of Mines has reviewed the literature related to the recovery of A1203 (alumina) from coal ash. A small amount of unpublished data is also reported. Of the processes studied, the alkaline-sinter process is the most promising from a technical standpoint. However, owing to the high cost of processing coal ash, the dispersed location of powerplants, and the domestic availability of higher grade alternate materials, coal ash does not rank as a primary source material for replacing imported bauxite.

Jan 1, 1979

By Heinz W. Sternberg

The literature on electrochemical treatment of coal is reviewed, and possible avenues of further research in this field are discussed in this report. Electrolytic reduction of finely distributed coal resulted in the addition of as many as 9 atoms of hydrogen to 100 atoms of carbon. Reduction of coal extracts at controlled potentials indicated the presence of condensed aromatic hydrocarbons and reducible quinones in coal. As much as 65 percent of low-rank coal can be made alkali soluble by electrochemical treatment. Higher rank coals gave smaller yields of alkali-soluble products. However, the nature of this reaction is not clear. The difficulty of reducing coal electrolytically is probably due to the insolubility of coal and not to any structural peculiarity. Reduction of coal by electrolytically generated radical anions appears to be a promising approach for further research.

Jan 1, 1962

The Bureau of Mines equipped a longwall shearer with a water-jet-assisted cutting system and measured dust levels during the cutting of a simulated coal block. The block was cut dry, at a conventional water spray pressure of 190 psi, and with water-jet-assisted cutting pressures ranging from 1,000 to 6,000 psi. At water pressures of 3,000 psi and higher, dust concentrations were reduced by as much as 85 pct via water-jet-assisted cutting in comparison with conventional water sprays. This reduction was achieved without any increase in the water flow rate.

Jan 1, 1986

By R. T. Johansen

The adverse effects on waterflooding and well-completion methods of clay minerals indigenous to petroleum-production formations recently have received considerable attention. Knowledge of the types and amounts of clay minerals present would allow estimates of the response of such formations to injected or infiltrated water; however, the random distribution of clays in sedimentary formations makes direct evaluation of ?water sensitivity? desirable. A method for the direct evaluation of water sensitivity has been developed, based on measurement of water-vapor adsorption. Correlation of such data with the results of nitrogen-adsorption measurements provides valuable information on the content and properties of clay minerals in sedimentary rocks. The method is relatively simple and has the advantage that it may be used with small, irregularly shaped chips or shale-streaked samples, as well as with typical core samples. Methods previously employed required separating the clay from the rest of the reservoir-sample material and then performing a clay analysis either by X-ray diffraction, differential thermal analysis, liquid permeability, or a combination of these methods (2,3) .3/ This water-vapor-adsorption method requires measuring only a few points on the isotherm to tell whether or not the sample is water sensitive. The goal of these measurements is not to determine the type or amount of clay present, but what will be its sensitivity to flood water. This method gives a direct means of solving this problem.

Jan 1, 1958

By Robert E. Barieau

This report describes a method for treating pressure-volume-temperature (PVT) data obtained with a Burnett compressibility apparatus. The method makes use of a general nonlinear least-squares technique developed at the Bureau of Mines Helium Research Center. It is assumed that an adequate functional form is available for the expression of the compressibility factor as a function of either the molal density or the pressure. The functional form of the compressibility factor can be either linear or nonlinear in the parameters to be evaluated. Formulas are given for calculating variances and covariances of all parameters evaluated and for calculating the variance of calculated quantities of interest.

Jan 1, 1967

By John J. Sammarco

Illumination plays a critical role in an underground miner?s safety because miners depend most heavily on visual cues to recognize hazards. Mobile mining machinery, located in the miner?s peripheral field-of-view (±10° to about ±60° off-axis), may pose potential pinning and striking hazards. The main objective of this research was to determine if there were peripheral visual performance improvements for the detection of moving objects when using cool-white light-emitting diode (LED) cap lamps as compared to incandescent (INC) light bulbs commonly used in miner cap lamps. The cap lamp variable of interest is the spectral power distribution (SPD); the illuminances were normalized by a diffusion filter. The second objective was to determine if age is a factor for peripheral visual performance. This is important because the workforce is aging ? the average miner age is about 43 years old. Thirty subjects participated in the study; ten subjects each in the age groups of younger (18 to 25 years), middle (40 to 50 years), and older (50+ years). Visual performance was quantified by the subjects? speed and accuracy of response to detect the rotation of high-contrast (white) circular targets located 3.83 meters (m) away at -20°, 40°, and 50° off-axis. The speed of detection and the number of missed target rotations (accuracy) were measured. The prototype LED cap lamp results were best with a 11% to 15% improvement compared to the INC and LED cap lamps respectively. Age does appear to be a significant factor. For the middle and older age groups?, target movement detection time increased 75% and 60% and the number of missed targets increased 500% and 450% respectively in comparison to the youngest age group. The results also suggest that target location is a significant factor. The subjects? target movement detection time for the 40° and 50° target movements increased 16% and 69% respectively as compared to the -20° target.

Jan 1, 2008

By George J. Conroy

Types and causes of short-circuit and open-circuit faults in mine portable trailing cables are discussed, and techniques for locating these faults are described. Time domain reflectometers (TDR) , tone generator, infrared sensing, and high voltage methods are covered. The paper summarizes Bureau of Mines research, including development of a ~DR/tone generator sender with auxiliary probe.

Jan 1, 1975

By H. C. Ko

As part of the Bureau of Mines effort to provide thermodynamic data for the advancement of mineral technology, the standard enthalpies of formation for ZnO?2ZnSO4 and COS04-6H20 were determined by HC1 acid solution calorimetry. The values are -550.31 ±0.28 and -641.33 ±0.15 kcal/mot, respectively.

Jan 1, 1982

Work on this program was supervised by R. C. Streeter, Project Scientist, R. K. Young, Principal Investigator, and R. A Glenn, Project Director Technicians involved in the conduct of the experimental work were J R. Allender, D. R. Wolber, G. L Maclay, and A. C Rupert The assistance of Project Scientists C. T. Ford in the electrokinetic studies, and R. R. Care in the spectrographic analyses, is also acknowl- edged. The valued advice and guidance during the course of this program from R. D Hill, EPA Project Officer, and Dr. D R. Maneval, Director of Planning and Coal Research for the Department of Environmental Resources, Commonwealth of Pennsylvania, is sincerely appreciated.

Jan 1, 1971

By Irven A. Jacobson

The thermal reactions of l-methylindole were studied in the temperature range of 525° to 627° C in a flow reactor. The major products consisted of 2-methylindole, 3-methylindole, indole, quinoline, hydrogen, and methane. 2-Methylindole is formed from 1-methylindole by an irreversible isomerization reaction. The 2-methylindole isomerizes in a reversible manner to 3-methyl-indole, the equilibrium favoring the 3-methyl isomer. Indole is formed directly from 1-methylindole. Quinoline is formed from l-methylindole, 2-methylindole, and 3-methylindole.

Jan 1, 1971

By Rad B. Langston, Ted J. Williams, John A. Marjerison, Rimas T. Pakalnis, Tom M. Brady, Doug C. Bayer, Mark J. Bren

Underhand cut and fill mining methods are used at the Lucky Friday, Stillwater, and Galena mines in the western US in an effort to safely mine in difficult ground conditions and as a primary mining method where access below the ore is limited. The method has evolved at each mine to meet the unique situations associated with their milling procedure and mine layout. Details of the operational aspects of the backfilling and mining cycles at each mine are presented in this paper, accompanied by a summary of the mechanical properties of the backfill and its in-situ geomechanical behavior.

By R. W. Van Dolah

The feasibility of formulating cap-sensitive slurry explosives for use in underground mines with potentially flammable gas atmospheres was examined. Formulations containing aluminum metal as sensitizer and sodium chloride to reduce incendivity were prepared; some were cap-sensitive and had adequate air-gap. Flaked aluminum metal rather than the atomized type proved to be the more effective sensitizing agent of the formulations tested for incendivity in the large gallery of the Bureau of Mines, some were found to be suitably nonincendive.

Jan 1, 1968

By L. B. Pankratz

Enthalpies above 298° K were investigated for four crystalline sodium borates by copper-block drop calorimetry. Determinations were made to 1,200° K for NaB02, 1,003° K for Na2B407, 1,005° K for NaB305, and 1,046° K for Na2Be013. No phase transitions or other thermal anomalies were found. The enthalpy determinations, when combined with known heats of formation at 298° K and other supplementary data, enabled the calculation of the heats and free energies of formation of the compounds to their melting points. Values of relative enthalpies, entropies, heat capacities, free energy functions, enthalpies of formation, free energies of formation, and equilibrium constants of formation were tabulated at even temperatures.

Jan 1, 1971

By Richard G. Geyer

One aspect of a program to improve the chances of survival following coal mine disasters is the development of a communications system which will allow surviving miners to make their circumstances known to rescue teams. Various communications techniques can be considered, including electromagnetic systems, acoustic systems, and hybrid systems. The electromagnetic and acoustic systems would be independent of existing mine communications systems and set up specifically for use in emergencies. Hybrid systems might use a short emergency link to existing telephone systems in the mine. Many variations are technically possible, and the primary task is in evaluating the relative merits of each, so that the most workable system can be selected.

Jan 1, 1973

To improve the efficiency and speed of under-ground post-disaster rescue operations. The Approach: Develop a battery-powered mine-rescue vehicle designed to carry rescue crews, rescued miners, and their support equipment. How It Works: The experimental vehicle, shown below, was designed and constructed by the Mine Safety Appliances Company under contract to the Bureau of Mines. ATV Manufacturing Company and Delco Electronics were subcontractors. A rechargeable, silver-zinc battery provides power to a 3-horsepower permissible motor, the speed of which is regulated by a solid-state controller. Three wheels on each side are independently driven by a chain and mechanical trans-mission.

Jan 1, 1974

By Robert King

Splicing portable trailing cables used in underground coal mines is usually less expensive in terms of capital outlay and production time lost than replacing them. However, handling trailing cables may result in electrical arcs, shocks , and burns. Also, destructive forces encountered during a mining operation may shorten the effective life of a cable splice. This report gives the results of an analysis of cable splice defects in an effort to establish cable splice performance criteria, determine testing standards for cable splices, establish guidelines for training programs in cable splicing, and indicate areas for improvement.

Jan 1, 1975