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By C. I. Pierce

The Bureau of Mines conducted laboratory tests to determine if ultrasonic energy could reduce either the residual water or oil content of petroleum reservoir-rock samples from Appalachian area oilfields. Brine-saturated core samples were flooded with oil to residual brine saturation and subjected to 20 kilocycles per second ultrasonic energy. Then they were flooded with brine to residual oil saturation and again subjected to ultrasonic energy. Additional water displaced as a result of the application of ultrasonic energy to the flow system ranged from 0 to 4.3 percent of the original brine and averaged 1.9 percent. The increase in oil recovery as a result of the ultrasonic energy ranged from 0 to 9.0 percent of the original oil and averaged 3.1 percent. On the basis of the tests, it appears that 20-kcps acoustic waves would not have field application for oil recovery.

Jan 1, 1968

By W. H. Eddy

Laboratory batch and small-scale continuous flotation tests were con-ducted by the Bureau of Mines on a mica waste tailing from Kings Mountain, N.C., to determine the feasibility of producing high-quality mica, feldspar, and glass sand. Mica was recovered by two methods; one was by flotation in an alkaline circuit, which produced a mica concentrate assaying 92.0 percent mica with a recovery of 87.l percent, and the other by flotation in an acid circuit, which produced a mica concentrate assaying 91.0 percent mica with a recovery of 79.4 percent. Continuous flotation processing yielded a feldspar concentrate assaying 1.10 percent Na20 and 13.50 percent K20, with recoveries of 66.4 and 80.6 percent, respectively. The feldspar tailing was high-quality quartz glass sand analyzing 98.6 percent Si02 and 0.02 percent Fe203.

Jan 1, 1969

By T. M. Kohler, G. L. Finfinger, D. M. Hyman, A. T. Iannacchione

The Bureau of Mines measured methane emission rates from an advancing salt face ranging from 15 to 56 ft3/ton (0.5 to 1.8 m3/t). Small room size, use of a continuous miner, and a well-defined ventilation system made possible air velocity and methane concentration measurements, These measurements, representing data from 18 production days, were con- ducted in an area of abnormally low grade salt, Methane emissions occurred primarily during the advance of the salt face by continuous miner.

Jan 1, 1982

By C. B. Manula, R. L. Sanford, R. A. Rivell

PART I. DATA INPUT FOR THE OPERATING PROTOTYPE [To run the Rail Haulage Model independent of the Production Sub-system, remove the production data from card type four through the blank card following END DATA on page B18 and change the fourth data element under ADDITIONAL DATA from 1 To 0.]

Jan 1, 1974

By C. S. ROBINSON, T. M. Romslo

This investigation was conducted jointly by the Bureau of Mines and the Geological Survey to obtain further information on the source and economic possibilities of the copper mineralization exposed on the Copper Giant group of claims, Ajo mining district, Pima County, Ariz. The Copper Giant group of claims was first brought to the attention of the Bureau of Mines by Joseph Hunter (deceased), Phoenix, Ariz., part owner of the claims. In December 1942 these claims, and an adjoining group, were investigated by T. C. Denton, mining engineer, formerly with the Bureau of Mines, and Nels P. Peterson, geologist, Federal Geological Survey. It was concluded the area could not be considered as a source of copper for immed- iate emergency needs and that further investigation of the area, at the time, was not warranted. In the spring of 1948 the lessee, J. H. Greenway Albert, requested Bureau of Mines assistance in developing the property. J. H. Hedges, former chief, Tucson Branch, Mining Division, and Lincoln A. Stewart, mining engineer, Bureau of Mines, made a cursory examination of the property and noted that at numerous places, low-grade copper mineralization appeared on fractures and bedding of the Locomotive fanglomerate and Ajo volcanics, which are thought to be of Tertiary age. During the period of May 11 through 14, 1949, Bureau of Mines engineers3 mapped and sampled two areas of mineral- ization. On June 2 and 3, 1949, the areas selected by the Bureau and three other nearby mineralized areas were investigated by C. A. Anderson and R. S. Cannon, Jr., of the Federal Geological Survey. As a result of these examina- tions, further investigation of certain areas was believed to be merited. The Copper Giant area was selected as the most favorable in which to carry out exploratory and development work. The field work on the project was started in October 1949 and completed in December 1949. It consisted of road building, trenching, sampling, topo- graphic and geologic mapping, diamond drilling, and logging of core. Samples taken on the project and during preliminary examinations totaled 64, of which 63 were surface samples. Diamond drilling, started October 10 and completed December 7, consisted of two holes for a total depth of 1,542 feet.

Mar 1, 1952

By Edward J. Kansa

In a Bureau of Mines study, unsteady, spherically symmetric, one-dimensional, compressible-flow (finite sound speed) equations were solved numerically for a spherical deflagration propagating concentrically in a spherical vessel with Mach numbers ranging from 0.2 to 0.7; trajectory histories agree with the infinite-sound-speed theory developed by Perlee, Fuller, and Saul (PFS). A preliminary result of this study shows that flames propagating with speeds greater than 20 pct the speed of sound in the unburned gas mixture generate a complex history of aerodynamic waves distributed throughout the spherical vessel. Although the average pressure and flame radius agree with those predicted by the PFS models, the aerodynamic waves have a pronounced effect on the flame velocity, differing appreciably from that predicted by the PFS model.

Jan 1, 1976

By D. E. Ingersoll

This report describes the preparation characteristics of anthracite from the Mammoth and Holmes veins in Schuylkill County, Pa., as determined by the Federal Bureau of Mines laboratory separations at specific gravities of 1.50 to 1.90. The Holmes vein anthracite contains approximately 13 percent ash, and the Mammoth vein contains about 9 percent as fed to the breaker. Crushing Broken, Egg, and Stove sizes from each vein produces Pea-size anthracite of lower ash content than that contained in Buckwheat No.1 size and smaller. The Buck-wheat No.5 size has the highest ash content of all the sizes examined. Potential recovery from a mixture of the two veins as received at the breaker, separated at 1.90 specific gravity, is approximately 64 percent of the feed at 11.0 percent ash. The same materials separated at 1.80 specific gravity yield about 61 percent with an ash content of 10.1 percent. All rejects are from the Holmes vein, because the entire Mammoth material is less than 10.0 percent ash.

Jan 1, 1960

By Donald N. H. Chi

The unsteady, one-dimensional, compressible-flow equations have been solved numerically for a deflagration propagating through a gallery of finite length closed at the ignition end and open at the opposite end. These equations were solved for two situations wherein (1) the propagating flame was extinguished after 0.1 sec or before the return of aerodynamic disturbances reflected from the open end, and (2) the flame was allowed to propagate a full 0.8 sec until it was extinguished. It was found that the process of sudden flame extinguishment creates rarefaction waves that, upon entering the burned zone, produce resonance within the burned cavity. For the relatively small value of the product of the expansion ratio (8.5) and the effective burning velocities of 7.4 m sec-1 for the first experiment and 4.9 m sec-1 for the second experiment, it was found that the acoustic approximation provides an adequate estimate of the pressures developed ahead of the flame during the system's early history.

Jan 1, 1974

By George H. Schnakenberg

Automation of coal mining activities at the face offers improvements in worker safety, health, and productivity. Introduction of integrated computer-sensor systems to current mining machines will enable these machines to perform some of the most hazardous tasks through supervised teleoperation. The U.S. Bureau of Mines is pursuing the development of the enabling technology necessary to achieve this goal. The research program consists of both basic and applied research, each focused on the fundamental issues of computer and sensor technologies. Short-term research is directed to providing computer-assisted, remote supervisory operation of present underground equipment; the long-term goal is the development of progressively more intelligent mining systems. The research program includes a review of robotic machine and autonomous vehicle technologies and of current mining technology, which provides a base for developing innovative mining methods; research in navigation and guidance technology, emphasizing control of a continuous mining machine; research on coal-rock interface sensing technology for horizon control, and rib thickness control in highwall mining; the development of computer systems and hierarchical architectures for real-time control; and development of expert systems for machine system fault diagnostics and predictive maintenance. This report presents a brief background and the current status for each of these research areas.

Jan 1, 1989

By Edward Thomas

In 1947 the Bureau of Mines, as an accident-prevention measure, decided to advocate the adoption of roof bolting (suspension roof supports) in coal mines where it appeared to be applicable. Subsequent experience has disclosed that the applicability of this support is more general than was first suspected; moreover, comparison of the accident records of mines before and after adoption of the roof-bolting method shows results that more than justify the effort and funds expended. The industry has responded enthusiastically, because roof bolting proved to be not only an accident-prevention measure but also one to increase productive efficiency. In some instances this increase in the productivity of men and machines has been almost incredible and has led many mining men to conclude that through some hocus-pocus they can now cast aside many or all of the time-proven rule of good mining practice. If this tendency is not counteracted, it could easily result in an increase of roof-fall accidents, which may outweigh the benefits of roof bolting and discredit an innovation in roof control that shows great promise of materially reducing our mining accidents. From an economic standpoint it may represent the margin between profit and loss in many mining operations. The purpose of this manuscript is not to propose an inflexible code or set of rules but to summarize the experience to date as a guide for those who have the responsibility for the installation and inspection of roof bolts. This experience consists of approximately 250 investigations of roof failure in which roof bolting was involved either directly or indirectly. It should be pointed out that many of these failures were controlled, occurring during experimental periods, and comparatively few of the accidental failures actually resulted in personal injury, yet a significant number represented potential hazards.

Jan 1, 1951

By Kenneth C. Stewart

This contract was directed toward a study of the attenuating properties of earmuffs as worn by miners. Two attenuation measurement procedures were utilized. Human subjects were tested in a diffuse sound field according to threshold shift procedures recommended by the American National Standards Institute and a physical measurement procedure was accomplished in the same diffuse field on the same human subjects with microphones placed simultaneously on the inside and outside of the muffs. All measurements were obtained in one third octave of random noise. The results of the study indicated that physical and psychophysical attenuation measurements are in essential agreement at frequencies from 125 Hz to 2 KHz. Above 2 KHz the psychophysical measurement demonstrates larger amounts of attenuation than the physical measurement. The difference in attenuation ranged from approximately 7.0 dB to 9.0 dB at frequencies of 4 KHz and above. A possible explanation for the observed differences in attenuation has been presented.

Jan 1, 1980

By H. L. Riley, B. W. Gandrud

"INTRODUCTION AND SUMMARYIn connection with a program of research work on coal at its Southern Experiment Station, the Bureau of Mines, in cooperation with the University of Alabama, conducts washability studies of samples of coal from coal fields in Alabama and other Southern States in which commercially important deposits of coal occur. The first such study on coal from a bed in the Arkansas field has been completed, and the results are presented in this report.One of the main objectives of a washability study is to obtain technically and commercially important data in connection with the best methods for preparing and utilizing the Nation's limited reserves of good coking coal. Such information is important from the standpoint of conservation in that it facilitates selection of preparation methods that will yield a good grade of coking coal with a minimum of losses of coal in the rejects.The coal on which this report is based was obtained by underground and tipple sampling at the quality mine of the Quality Excelsior Coal Co. about 3 miles east of Hackett, Ark. This mine operates in the Upper Hartshorne bed, which, as the main source of coal in what is known as the Hackett-Excelsior district, yields an excellent grade of low-volatile coking coal, which is marketed at steel plants in Colorado and California. Production from this bed by the major producers in the Hackett Excelsior district was at the rate of about 125,760 tons annually in 1949, according to the Keystone Coal Buyers Manual. 2/In the laboratory, the tipple sample was crushed to 6-inch top size and screened on a 2-inch round-hole screen. The 2-inch to 0 undersize, amounting to 71.4 percent of the total sample, was fractionated into a series of screen sizes and float-and-sink products to get data for determining the washability characteristics of the coal. Before the screening and float-and-sink tests were made, however, machine cuttings, which are now gobbed underground, were added to the 2-inch to 0 sample. Enough of these cuttings were added so that the resulting mixture was considered representative of what the 2-inch to 0 run-of-mine coal would be if all machine cuttings, including the part now being gobbed, were brought to the tipple as a part of the run-of-mine coal.The mixture obtained referred to in this report as the run-of-mine or raw coal."

Mar 1, 1953

By D. R. Corson

The Bureau of Mines instrumented two similarly backfilled stopes--one filled in the normal manner and the other with the fill densified using vibratory compactors--to evaluate the effect of fill compaction on subsequent vein-wall closure proposed as a adjunct process for strengthening cemented fill. Hydraulic pressure cells to monitor pressures within the fill and mechanical closure devices to measure vein-wall movement and the procedure for their installation are described. The field compaction work was generally performed manually by utilizing small commercial concrete vibrators. A prototype immersible vibrator using slusher cables to propel the vibrator in the stope was used on several lifts of fill. Although compaction efforts were less effective than anticipated in increasing the final density of fill, analysis of the field data does indicate somewhat improved strain characteristics and an increased pressure buildup for the densified fill. The effects of a prolonged period of inactivity and of rock burst occurrences in the immediate area are also reflected in plots of strain and pressure within the two instrumented stopes.

Jan 1, 1971

By J. R. Allsup

In cooperation with the Division of Advanced Automotive Power Systems Development, Environmental Protection Agency, the Bureau of Mines studied a conventional spark-ignition engine as a prime mover for use in a hybrid system. The study involved both steady-state and transient engine operation with ignition timing, air-fuel ratio, exhaust gas recirculation, oxidizing type catalytic converters, engine speed, and power output as variables. Data were obtained from two 1971 model 350-cubic-inch-displacement engines mounted on engine dynamometer stands. When the hybrid engine was operated with an oxidizing catalyst at power output levels required for a 4,000-lb curb weight hybrid vehicle, carbon monoxide and hydrocarbon emissions could be reduced to approximately 2.0 grams and 0.3 gram per brake horsepower-hour, respectively. With exhaust gas recirculation, oxides of nitrogen emission levels could be reduced to approximately 1.2 grams per brake horsepower-hour.

Jan 1, 1974

By V. R. Spironello

One of the primary objectives of the Bureau of Mines solid waste utilization program is the recycling of the magnetic fraction of municipal solid waste called raw refuse scrap. In this investigation, several types of scrap of differing quality, including refuse and turnings, were melted in a 1-ton electric-arc furnace in various combinations to produce steel in noncritical (construction) grades. In-formation on furnace operation and on the behavior of tramp and alloying elements was obtained. The research showed that it is possible to produce acceptable steel from a variety of steel scrap. Although some scrap is routinely used in steelmaking, it was found that up to 50 to 55 pct of the scrap charge can be ref-use, provided it is combined with higher quality scrap. The chemistry of the steels was generally acceptable, and all of them were rolled without difficulty. The specification (ASTM 615) for the steels produced was grade 40 or grade 60, containing 0.30 or 0.40 pct C, with mini-mum yield strengths of 40,000 or 60,000-psi, respectively. Most of the steels met the specification requirements. In-formation on typical microstructures of some of the steels is included. The composition of some furnace dusts showed high levels of Sn, Pb, and Zn.

Jan 1, 1981

By Joan C. Biordi

[Composition profiles for atomic, radical, and stable species, as well as temperature and area expansion ratio profiles, have been determined for a nearly stoichiometric CH4-02-Ar flame and one to which 0.3 percent CF5Br inhibitor had been added. Net reaction rate profiles were calculated for all the observed species. For the normal flame, these and the mole fraction profiles gave rate coefficient information about the elementary reactions in the methane flame, for example, CH. + 0 4- H2CO 0 H, k4 = 1.05 X 1014CM3 mole-1sec-1 for 1,550§T 0,725' K; CO + OH 4 C02 + H, k6= 4.7 X 1011 for 1,350{T X1,750° K. Comparison between the inhibited and normal flame showed that A] and [CH3] were significantly reduced at the lower temperatures in the inhibited flame even though in the hot gas region the [E] [OH!, and [0] were essentially the same in both flames. The CF3Br disappears very early in the flame, relative to the fuel, and the reaction primarily responsible for its disappearance is H v CF3Br 4 HBr + CF3, where k7 is found to be 2.2 X 1014 exp(-9460/RT) for 700-1,550° K. Reaction of the inhibitor with methyl radicals provides for the relatively small amounts of CH3Br observed, but CH3 + Br2 - CHs Br + Br must also occur. The HBr formed reacts rapidly with H atoms to form H2 and Br, but the reaction is soon "balanced" in the flame as may be demonstrated by calculation of the equilibrium constant at various temperatures. The fluoro-carbon fragment produced in reaction (7) also reacts rapidly, in part with methyl radicals to give the observed elimination product CH2CF2 Later in the flame, above -1,400' K, F2CO is formed from the reaction CH2CF2 + 0 P F2CO + CH2 and k., -1.5 X 1013 at 1,600° K. The rather slow decay of carbonyl fluoride is attributed to reaction with H atoms according to the sequence F2CO I H - HF + FCO and FCO + H HF + CO.]

Jan 1, 1975

By Joseph S. Coffman

The Bureau of Mines investigated the availability of barite (BaSO4) from 35 U.S. and 41 non-U.S. mines and deposits in 17 market economy countries (MEC's). This evaluation assesses the availability of mud-grade barite, and concentrates consumed by the chemicals and fillers industries. The demonstrated resources defined in this analysis totaled 130 million metric tons (Mmt) of barite (contained BaSO4), yielding a potential 115 Mmt of recoverable barite concentrates. At the 1984 MEC production rate, the evaluated resources would last about 30 yr; however, this would include production costs of up to $100/mt concentrate. An average price needed to cover all costs of production over the life of each operation was determined for both mud-grade and chemical- and filler-grade barite products. Including a 0-pct discounted-cash-flow rate of return (DCFROR), regional weighted- average total production cost ranged from $38/mt for barite concentrates in Asia to $71/mt for U.S. operations. Transportation costs have the greatest impact, contributing up to 60 pct of the total cost of production. Rail transportation costs from the mines to U.S. markets are generally significantly higher than ocean shipping rates on imports.

Jan 1, 1986

By F. L. Klinger

CRUDE OIL refining continued to be the foremost industry of Bahrain in 1963. This island, the largest of a group 30 kilometers off the Saudi Arabian coast, is the site of the first petroleum discovery in the Persian Gulf and in the Arabian peninsular region. The island's only oilfield was discovered in 1932; exports of crude began in 1934 and the refinery was built in 1936. Although its crude oil has been less than 1 percent of annual Middle East output in recent years, Bahrain has been an important refining center for many years, processing a substantial portion of Saudi Arabian petroleum as well as all local production. The Bahrain refinery annually accounts for 17 percent 0 the petroleum products produced in the Middle East and 25 percent of the exports. Bahrain's mineral resources consist of oil, gas, and basic construction materials. Petroleum production and refining are the important mineral industries and contribute most of the national income by payments for taxes, wages, and local services including construction and material supply. The petroleum industry has supported a large share of local business and extensive indirect employment, and its early establishment also helped Bahrain to strengthen its position as a trading center in the Persian Gulf. The country's entrepôt trade produces about 20 percent of Government revenue, and Bahrain is somewhat less dependent on the petroleum industry than are the neighboring States to the west.

Jan 1, 1964

By Katherine A. Margolis

Refuge Chamber Expectations Training was created by a multidisciplinary team at the National Institute for Occupational Safety and Health (NIOSH) to inform miners of what to expect psychologically and physically if it became necessary to use a refuge chamber in a mine emergency. The presentation can be used either for one large group or for individual miners. The training is a multimedia Adobe Flash presentation containing pictures, audio, video, and interviews with miners who have used a refuge chamber in an emergency. It must be run on a computer with Adobe Flash Player installed (refer to the computer system requirements section).

Oct 1, 2009

By Susan M. Moore

Many challenges are faced by workers in lower-seam (42 inches or less) mines. The lower-seam heights confine mine workers to their knees as they perform their daily tasks such as installing roof bolts, delivering supplies, repairing belt, or cutting coal. Miners working in these lower seams often consider kneepads to be their only line of defense against knee injuries. However, healthy knees do not start and stop with kneepads. Other interventions such as changing postures, proper hygiene, and work station design may also be used to reduce mine workers? risks for developing knee injuries. Incorporating these and many other interventions into a mine worker?s ?way of life? is an important step to ensuring a long, healthy career and retirement. Keeping knees healthy is also a key aspect to reducing costs in low-seam mines as the industry battles rising health care costs, and training/recruitment of replacement workers is time-consuming and costly. Educating the workforce about the possible interventions to reduce knee injury risk is a primary objective for the National Institute for Occupational Safety and Health?s (NIOSH) Pittsburgh Research Laboratory (PRL). Therefore, NIOSH researchers, along with industry and academia, developed a training package to educate the mining com­munity about some possible interventions beyond kneepads that may be used to help decrease knee injury rates. Increased awareness and simple changes are the first steps to reducing knee injuries.

Jan 1, 2008