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By W. H. Ode, W. A. Selvig

"INTR0DUCTIONAccording to the Standard Specifications for Classification of Coals by Rank of the American Society for Testing Materials (A.S.T.M. Designation: D388-38).1/ high-volatile bituminous coals, subbituminous coals, and lignites are classified on the basis of calorific values on the ""moist"", mineral-matter-free basis. The moist basis refers to coal containing its natural bed moisture but not including visible water on the surface of the coal. It is assumed that the natural bed moisture of coal in the ground represents the moisture-holding capacity of the coal when in equilibrium with air at approximately 100 percent relative humidity. This moisture is sometimes referred to as inherent moisture as opposed to extraneous moisture, which wets the surface of the coal.To simplify procedures for determining the moisture-holding capacity of coal it is assumed, for all practical purposes that the moisture content of coal when brought to a standard condition of moisture equilibrium in an atmosphere of 97 percent relative humidity and 300 C. represents the bed moisture of the coal. The A.3.T.M. specifications provide that this condition of moisture equilibrium shall be obtained by bringing the coal to a standard condition of moisture equilibrium at 300 C. in a vacuum desiccator containing a saturated solution of potassium sulfate (97 percent relative humidity) according to the procedure proposed by Stanfield and Gilbart. 4/ No mention is made in the specifications for bringing partly air-dried samples to their natural bed moisture condition probably because of the hysteresis effect that has been noted by various investigators. 5/ In this connection it has been found from sorption studies that the adsorption and desorption curves for lignite are not entirely reversible. The hysteresis effect has been explained by some investigators as resulting from shrinkage of the lignite during drying, which causes a collapse of some of the capillaries, so the dried lignite cannot take up as much water as it held originally."

Apr 1, 1953

By R. R. Wells

This report summarizes the results of laboratory testing of copper-bearing magnetite ore from the Poorman, Bush & Brown, and Copper Center deposits, Kasaan Peninsula, Prince of Wales Island, southeastern Alaska. The ores contain minor amounts of chalcopyrite and pyrite. Intimate association of these sulfides with magnetite necessitates fine grinding for adequate liberation and rejection of copper and sulfur and for the production of high-grade iron concentrate low in objectionable impurities. Laboratory tests indicated that the optimum results can be obtained by flotation of ore ground to minus-100-mesh, with subsequent wet magnetic separation treatment of the flotation tailing. A summary of results obtained by this treatment of the three samples tested is shown in table 1.

Jan 1, 1957

By M. S. Oudenhoven

The Bureau of Mines conducted an investigation to determine the theoretical stress distribution in the vicinity of explosively expanded rock bolt anchors independent of their bolts. Plane-strain solutions applicable to this problem were obtained by combining the field pressure with the uniform pressure that would be produced by vertically placed anchors having 2-, 3-, and 4-foot spacings. High rock stress which would be produced by an anchor was localized, as would be expected from St. Venant's effect, and increased as the field pressure decreased.

Jan 1, 1967

By Mackenzie Burnett

The Brattice Window Method was used to measure the leakage rates of a total of 42 ventilation stoppings in 8 hardrock mines. Various types of stopping construction were evaluated. The following types are listed in order of decreasing effectiveness: 1) Cinder block, 2) Timber and mortar, 3) Timber and polyurethane foam, and 4) Timber and brattice material. There are slight differences in the effectiveness of the first three types, while the timber and brattice type is substantially inferior to the others. The repeatability of the Brattice Window Method was found to vary with physical conditions in the mine such as stopping location with respect to intersections, regularity of drift cross section, and the presence of hardware such as air and water pipes, timber sets and wire mesh. The Brattice Window Method is viewed primarily as a tool for estimating and comparing stopping leakages for the purpose of determining where repair efforts should be concentrated. A laboratory test program resulted in the derivation of several "rules of thumb" for employing the Brattice Window Method, which will aid in securing accurate and repeatable data.

Jan 1, 1979

By J. J. Jakowsky

[The legislation in many States against the present method of producing carbon-black by the incomplete combustion of natural gas, and the continually increasing demand for gas for otter purposes, indicates that the supply of carbon-black may Gradually be decreased and that new methods for its production, utilizing a greater parentage of the carbon in the has should be developed. In the course of investigations of the effects on hydrocarbons of high voltage discharges, it was noted that under certain conditions natural gas could be decomposed and that carbon-black could be produced. The effects of several tyres of electrical discharges on natural gas have, accordingly, been studied' in order to find out the fundamental factors underlying the reactions and their possible influence in the recovery of a greater part of the carbon content of natural gas than is now possible. Present commercial plants using natural gas for the manufacture of carbon-black recover from 0.9 to 1.5 pounds of carbon-black per thousand cubic feet of gala consumed, or less than 5 per cent of the total Gabon in the gas: It should be noted, however, that the, present methods involve heating the gas to incandescense by burning it as a luminous flame, and a considerable part of the gas is thus consumed as a source of hest. If this heat can be supplied from some other source, or if a more efficient method of applying the energy con. tamed in part of the gas, to the decomposition of the rest of it, can be worked out, then a greater yield of carbon-black per thousand cubic feet of gas care be expected. The present abort paper contains a brief summary of tie investigations so far conducted upon natural gas.]

Jan 1, 1922

By R. M. GRANTHAM, J. H. SOULE

C. R. Keyes, F. C. Schrader , F. A. Jones ( the first director of the New Mexico School of Mines , whose name was given the deposits ) , and N. H. Darton all described the Jones iron deposits within a decade after their discovery in 1902 . The earliest locations now on record were made in 1927. Interest in iron ores was revived during the second World War . Paul E. Pesonen , of the Bureau of Mines , reported on the deposits in December 1941 and proposed an extensive exploratory program . In March 1942 , the deposit was reported upon by C. H. Johnson , also of the Bureau of Mines , and a definite program of exploration was outlined .

Feb 1, 1947

By Michael Sokaski

A dense-medium cyclone pilot plant was built to clean 112-inch to 0 size coal. This pilot plant does not require the removal of the extremely fine material (usually minus 1/2-mm) from the feed, which is necessary in conventional dense-medium cyclone plants. The essential difference between conventional cyclone plants and the pilot plant is in the medium-recovery system. The latter uses a combination of sieve bend screens, classifying cones, and magnetic separators for medium recovery. Eight tests were run in the pilot plant at a feed rate of 5 tons per hour with four different raw coals and one crushed jig middling product. Sharp separations were obtained as indicated by an average error area of 27 and probable error of 0.047 for the 112-inch to 200-mesh size range. Magnetite loss averaged about 2.5 pounds per ton of feed. The influence of several factors on cleaning performance of the cyclone was investigated. The diameters of both the overflow and underflow orifices were found to be important for optimum cleaning performance, but these diameters could vary over a wide range without serious effect; however, if this range was exceeded, cleaning performance deteriorated. Better cleaning performance was obtained when the cyclone inlet pressure was increased from 9 psig to 13 psig. The size of the magnetite particles in the medium was found to have a substantial effect, and the best cleaning results were obtained with grade B magnetite. Demagnetizing the magnetite in an effort to decrease the effective particle size did not improve cyclone performance.

Jan 1, 1963

By Richard D. Graves

Pitch from low-temperature carbonization of bituminous coal was hydrogenated at cracking conditions in a continuous bench-scale unit to produce low-molecular-weight oils and tar acids. The pitch contained 15.6 pct benzene-insoluble material, 4.0 pct hexane-soluble oil, and 80.4 pct asphaltene by weight. At 475° C, 7,500 psig, and 1.5 hours residence time, hydrogenation products, based on the weight of pitch, were about 36 pct oil boiling below 325° C, 24 pct hexane-soluble heavy oil, 17 pct asphaltene, 1 pct benzene insolubles, and 12 pct hydrocarbon gases. The yield of tar acids boiling below 250° C was 4.3 pct, and the yields of C6 to C8 paraffins, naphthenes, and aromatics were each less than 1.0 pct. The yield of tar acids was within the range of yields obtained by hydrogenation or high-temperature carbonization of bituminous coal (2 to 5 wt pct). Yields of oil boiling below 325° C increased with increased residence time or temperature. There was little or no effect of residence time on yields of alkali- soluble material which contained tar acids. Yields of hydro-carbon gases increased markedly with an increase in temperature from 475° to 500° C. Lowering the hydrogen pressure to 4,500 psig resulted in yields similar to those obtained at 7,500 psig.

Jan 1, 1962

By John C. Feeley

The methods used and the funds available for the development and oper- ation of shall mines and the reopening of small abandoned mines frequently present problems that tax the ingenuity and resourcefulness of the mining engineer far beyond that required in the mass production from large deposits. The objective of this paper is to describe in considerable detail the means whereby engineers have solved local problems in reopening an abandoned mine at which equipment, facilities, and funds were limited... The Etowah Coal & Iron Co. Gadsden red-iron-ore mine at Gadsden, Ala., 18 of interest in this category since it is the only independent red-ore mine under active development in the State. All other red-ore mines in Alabama are owned or controlled by the large iron or steel companies. The The mine, located on the southwest end of Shinbone Ridge in the outskirts of Gadsden lies in an ares once productive. but now idle, for many years. ore is relatively highgrade compared with that in the Birmingham area, but the bed is thin and somewhat lenticular. The presence of a large blast furnace at Alabama City, 3 miles from Gadsden, and the growing scarcity of red-iron ore supplies for it offered inducements for reopening the mine in 1946. Up to the time this circular was prepared (1947) only a small quantity of ore (about 1,500 tons) has been produced and shipped to the furnace. A force of 14 men was employed in sinking the main slope and developing a third "lift" (a local term for level) 100 feet below the old mine workings.

May 1, 1949

By D. P. Schlick

As of June 30, 1970, Federal regulations required the operator of each underground coal mine to maintain the average concentration of respirable dust below legislative standards. As of March 1, 1971, over 152,000 respirable dust samples have been processed by the Bureau of Mines. Approximately 75 percent of underground working sections are being sampled in accordance with Federal regulations. Results indicate that 72 percent of the sections which have completed at least one basic sampling cycle are below 3.0 mg/m3, the standard in effect under the Federal Coal Mine Health and Safety Act of 1969 (P.L. 91-173). Notices of Violation were issued on 1,670 underground mines for failure to begin a sampling program; Withdrawal Orders were issued in 64 of these instances. Notices of Violation were issued on 1,121 sections where applicable dust levels were exceeded; Withdrawal Orders were issued in seven of these instances. There are 381 mining sections currently operating on permit; from the interim Compliance Panel.

Jan 1, 1971

By Joseph Cervik

This Bureau of Mines report deals with water infusion of coalbeds, which can control methane emission at face areas during developmental mining and which may sometimes suppress dust. Studies show that water infused into the coalbed flows through the fracture system and displaces the methane in the fractures and prevents migration from the solid coal. Displaced gas migrates away from the face area that has been water infused and enters the return ventilation airways. A gradual decrease in methane emission is observed from the start of infusion until the infused zone is mined through. Depending on the permeability of the coalbed, infusion pressures ranged from 300 to 2,200 lb/in2. Face emissions in the Upper Kittanning coalbed were reduced by 89 pet; reductions of 38 to 79 pet were measured in the Pittsburgh coalbed depending on the relationship between the face cleat direction and mining direction. Respirable dust levels were reduced by about 75 pct on a longwall section in the Pocahontas No.3 coalbed and by about 50 pct on a development section in the Upper Kittanning coalbed, but no statistically reliable reduction was found in the respirable dust levels in the Pittsburgh coalbed.

Jan 1, 1977

By R. O. Dannenberg

A metallic displacement process, utilizing easily available steel wool or steel window screen, was devised and successfully used for the recovery of silver from waste photographic fixing solutions. Laboratory and prolonged commercial-scale testing established that the iron filament type unit will efficiently precipitate silver, as a high-grade sludge, from acidic waste photographic fixing solutions ranging in grade from less than 1 to over 10 grams of silver per liter. Data and design information are presented to facilitate the construction and operation of a practical unit of any desired size. A smelting process for recovering pure silver from precipitated sludge containing 27 to 80 percent silver was devised.

Jan 1, 1968

By R. A. Meyer

A table that greatly simplifies determination of metastable transitions in mass spectra has been prepared. All the mathematically possible metastable transitions of any compound whose molecular weight lies between 26 and 150 can be determined from the table without calculation. The method of utilizing the table is described, using selected peaks from the spectrum of normal butane for illustration. In the mass spectrometer, ions are formed in the isatron and accelerated through a series of slits. Most of these ions reach the collector without further change, but a few dissociate in transit to form new ions. These ions appear in the mass spectrum at neither the mass--to-charge ratio (m/e) of the original ion nor that of the new ion. A formula that relates the appearance of these new ions to the ion from which they were formed is: [ ]

Jan 1, 1957

By R. C. Hickman

"INTRODUCTION .As part of its spot drilling program, the Bureau of Mines core-drilled seven holes on the Alexander and Barber properties in Spartanburg County, S. C.Extensive surface float and outcrops of sillimanite schist on these properties appeared to justify drilling, which did not prove satisfactory, however, owing to the spotty occurrence of the schist bodies and the poor core recovery in the decomposed schist.ACKNOWLEDGMENTSIn its program of exploration of mineral deposits the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, Oliver C. Ralston, chief, analyzes samples and performs beneficiation tests.This project was under the immediate supervision of Mitchell H. Kline, chief, Raleigh Division, Mining Branch, Bureau of Mines.LOCATIONThe Alexander and. Barber properties are in the southern part of Spartanburg County, S. C. The Alexander property is about 5 miles cast of Woodruff. It is reached from Woodruff by driving east 5 miles on a macadam road to the intersection with an unsurfaced road near Unity Church. The farm house on the property is 0.4 mile north on this road. The sillimanite outcrop is in a field approximately 1,200 feet east of the farm house. The Barber property is about 2 miles north along the unsurfaced road that passes the Alexander property."

Sep 1, 1947

By Alan D. Hartman

Instabilities in electric steelmaking furnace arcs cause electrical and acoustical noise, reduce operating efficiency, increase refractory erosion, and increase electrode usage. The U.S. Bureau of Mines is investigating methods to stabilize these arcs. To perform experiments to test new hypotheses, Bureau researchers designed and instrumented an advanced, experimental single-phase furnace. This report describes this furnace, which was equipped with high-speed data acquisition capabilities for electrical, temperature, pressure, and flow-rate measurements; automated atmosphere control; ballistic calorimetry; and view ports for high-speed cinematography. Precise environmental control and accurate data acquisition allow the statistical design of experiments and assignment of rigorous confidence limits when potential furnace or procedural modifications are tested.

Jan 1, 2010

By S. J. Pearce

The need for a simple, very sensitive, and accurate method for the determination of benzene in blood and urine was evident throughout a recent study of chronic benzene (C6H6) poisoning conducted cooperatively by the United States Bureau of Mines, The Barrett Company, and the producers of benzene. A combustion method which will be described in a later publication, end a previously described5/ adaptation of Smyth's method were developed and used during that investigation. The adaptation of Smyth's method gave satisfactory results when dealing with exposure conditions that produced chronic poisoning in a comparatively few days, but it was time-consuming and lacked the accuracy necessary for a study of the absorption, distribution, and fate of benzene in the body during exposure to threshold concentrations of benzene vapor in air. The combustion procedure was satisfactory from the standpoint of sensitivity but was cumbersome, intricate, time-consuming, and required the use of special and somewhat expensive physical and. chemical apparatus. Following the termination of this study of chronic poisoning, possibilities for developing better methods occurred, and these have been investigated by the Bureau of Mines with the aid of Relief Works Division personnel. A microcolorimetric method for the determination of benzene in air has been described recently.6/ The present report deals with the adaptation of this new colorimetric method to the determination

Jan 1, 1936

By James A. Wasson

This report analyzes the petroleum-production potential of the basal Greenbrier dolomite zone, Sycamore-Millstone field, Sherman District, Calhoun County, W. Va., through the application of certain secondary-recovery methods. The well logs obtained and the core recovered from a well in this formation permitted an evaluation of the productive capability of the reservoir, Approximately 120,000 stb of oil may be produced from a 20-acre five-spot unit at breakthrough if the property is waterflooded. At an assumed limiting producing gas-oil ratio of 20)000 sef/stb, approximately 69,000 stb of oil should be recovered by low-pressure gas drive.

Jan 1, 1967

By Suresh K. Bhatt

This U.S. Bureau of Mines report reviews major developments in continuous haulage technology for underground coal mines. Haulage systems, both in use and under development, were investigated through a comprehensive literature search and visits to mines and manufacturers. The systems include flexible conveyor train, mobile conveyor, monorail bridge conveyor, multiple-unit continuous haulage, extensible, and belt turning systems. Strengths and weaknesses of the systems are assessed in light of their operating under remote control and their application to the computer-assisted continuous mining machine research being conducted by the Bureau. Through mining scenarios, candidate haulage systems are conceptualized to be consistent with the capabilities of the mining machine.

Jan 1, 1991

By E. Morrice, R. D. Smith

Thermal expansion and electrical resistance measurements were made on cerium metal from 4° to 300° K. The apparatus developed , including a specimen holder and a cryostat system , are described along with the experimental techniques used in obtaining the measurements . The total linear thermal expansion Data at of 99.83 weight - percent cerium metal between 4 ° K and room temperature was 4.24 percent . The resistivity at 4° K was 7.0 x 10-6 ohm- centimeter . 4° K indicate a fundamental relationship between residual resistivity and purity of cerium metal . The effects of annealing and repeated thermal cycling on resistivity were determined .

Jan 1, 1964

By C. H. Herty

Manufacturers and consumers of steel have come to realize during the past few years that cleanliness is of great importance in steels which must meet rigid specifications for various physical properties. Of equal importance is the consistent production of steel which is uniform in these properties. For maximum utility, steels should be uniform not only from heat to heat, but also from ingot to ingot and within each ingot. In the manufacture of killed steels such as the higher carbon forging grades, uniformity as indicated by the usual chemical analysis is easy to obtain, provided that a normal top discard is taken, as is al¬ways the case in steels poured with hot-top practice. No such uniformity, however, holds true for the nonmetallic matter, which consists for the most part of the products of deoxidation of the steel. For a large tonnage of steels which go into articles manufactured by deep-drawing processes, killed steel has never been successfully applied because with the present deoxida¬tion practice, low-carbon killed steel is almost invariably extremely dirty. To obtain the desired qualities for deep drawing, the steel is rimmed, - that is to say, deoxidized with manganese and perhaps a small amount of aluminum, - the resultant product being of high purity in the skin of the ingot, but very badly segregated at the center of the ingot, particularly in the upper-central section. This segregation necessitates a very heavy top discard, and one of the major segregates is carbon which renders the steel too hard to draw properly. If clean, low-carbon killed steel could be made successfully, much better ingot yields would be obtained than by the present rimming steel practice. Furthermore, banded structures and outside and inside seams, which are undoubtedly due in a large measure to blowholes in the ingot, are defects which are very difficult to control in rimmed steel. These defects would be minimized by clean killed steel.

Jan 1, 1931