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By H. W. Kilau

The Bureau of Mines used a high-temperature rotational viscometer to test basic oxygen furnace slags to determine fluorspar requirements and to evaluate colemanite and fused boric acid as substitute fluidizers. A continuous technique of viscosity measurement was adapted to better determine the viscosity-temperature profiles of volatile fluorspar slags. Criteria used for estimating slag fluidizer effectiveness were (1) the apparent solidification temperature, and (2) the temperature range of slag crystallization. Colemanite and fused boric acid in high-basicity slag were superior fluidizers to fluorspar when compared on the basis of boron versus fluorine concentration. Fused boric acid was nearly equivalent to ceramic-grade fluorspar when compared on a simple weight basis, while colemanite was inferior to fluorspar. Fluorspar slags volatilized fluorine during viscosity testing. Colemanite and fused boric acid slags were stable, no boron losses being detected. A fluidizing limit was found for fluorspar at 2.9 percent fluorine concentration; higher concentrations impaired viscosity and caused foaming and crusting of slag. Concentrations of boron up to 4.4 percent resulted in very fluid slags with no fluidizing limit.

Jan 1, 1978

By Wilbert J. Huff

The work of the Explosives Division, Bureau of Mines, United States Department of the Interior, for the fiscal year ended June 30, 1939, is described in the following pages. This paper is the fourth of a series of annual reports covering the activities of the division since July l, 1936.

Jan 1, 1940

By R. V. Ramani

In this the available information friction factors and leakage report, on characteristics are reviewed and summarized. The use of Penn State Mine Ventilation Simulator (Volumes II and III of the Final Report) to analyze the sensitivity of the ventilation system to the changes in leakage and friction factors is discussed with examples. In simple ventilation systems, the results of changes in leakage and friction factors can be easily solved and explained by the laws of air-flow. In complex systems, with fixed quantity branches and multiple sections, the effect of changes in leakage and friction factors cannot be generalized. This study points out the importance of good input data for obtaining reliable information from computer analyses and demonstrates the application of simulators to analyze the effectiveness of ventilation systems. An extensive bibliography on friction factors, leakage characteristics and ventilation economics is included.

Jan 1, 1977

By W. J. Wenger

Analytical, geographical, and geological data on 67 samples of crude oils from Utah are presented, along with some correlations and interpretations. Most of the, geologic formations that produce oil in other areas are also productive in Utah; and as in many other locations, the Permian, Pennsylvanian, and Mississippian formations account for the major amount of the total oil produced in the State. Some anomalies and unusual phenomena are noted. Although most Utah oils are low in sulfur, a sample containing the highest percentage of sulfur ever recorded by the Bureau of Mines is among the oils discussed in this paper. Most of the oil from the major producing formations in Utah is low in sulfur; the same formations produce high-sulfur oils in adjoining Rocky Mountain States. Some Utah oils are both waxy and asphaltic, an unusual combination of characteristics. Correlation index curves for some oils are shown suggesting compositional differences in oils from different producing formations. Production statistics trace the rapid rise of oil production in the State after the first commercial discovery in 1947 and indicate a decline in amounts produced since 1959, the year of peak production in Utah.

Jan 1, 1971

The principal activities of the Bureau of Mines Explosives Research Center from July 1, 1962, to June 30, 1963, are described briefly in part 1. Part 2 gives short abstracts of publications that appeared during fiscal year 1963; in general, the research reported in these publications antedates the report period.

Jan 1, 1965

By Michael T. Nigbor

The Bureau of Mines assisted the Rocky Mountain Energy Co. in a pilot-scale in situ leaching experiment at Casper, Wyo., to determine if sulfuric acid can be used as a cost-effective alternative lixiviant (leachant) for uranium in situ leaching. This experiment, which lasted more than 2 years, is the first fully documented pilot-scale operation in which the leaching-restoration cycle was completed using sulfuric acid instead of the more common carbonate-bicarbonate leachant This report describes activities at the experimental site, presents extensive geochemical data from startup to site restoration, compares laboratory and field experiments, and discusses the environmental aspects of acid leaching. The data showed that sulfuric acid is apparently an effective leaching solution. Three to five grams of acid per liter of ground water resulted in a production solution grade of 80 to 100 ppm uranium. Restoration was successful, but required extended flushing. The pH was the last chemical parameterto return to baseline, requiring about 350 days. This was longer than was predicted in laboratory simulations. The data also showed that mobilization of toxic elements such as selenium, arsenic, radium, thorium, and molybdenum stayed within reasonable limits and quickly fell back to preleach concentrations during restoration.

Jan 1, 1982

By H. B. Hill

The discovery of the Oklahoma City field and its .rapid development into one of the major oil-producing districts is an outstanding epoch in the history of the petroleum industry not only of .Oklahoma but also of the United States. The relatively great depth to which the wells were drilled and the large initial production of high-gravity oil are of special significance. The field has boon under proration almost from the time that its development began, and many new production problems have developed out of the changed conditions of operation. The discovery well was first tested in December 1928 at a depth of 6,402 feet, with an initial production of 4,847 barrels of 38.5° A.P.I. gravity and several months later was completed at a depth of 6,624 feet. The large initial production, the high pressure, and the large gas volume in the different horizons of the discovery well suggested the potential possibilities of gas and oil, production in formations of Pennsylvanian and pre-Pennsylvanian age.

Jan 1, 1933

By Charles D. Litton

This Bureau of Mines report presents a discussion of the essential components of pneumatic monitoring systems and their associated functions. Design criteria are presented which can be used for the design and fabrication of pneumatic monitoring systems having total system response times on the order of 15 to 30 min. To illustrate the utility of these design criteria, two detailed design examples are presented,

Jan 1, 1983

By Thomas M. Barczak, Christopher Mark

Roof supports can only be understood in conjunction with the rock structure that they support. The strength of the rock depends on geology, and the loads are applied primarily by the in situ and mining-induced stresses. Other factors, such as wider spans and retreat or multiple-seam mining, can also reduce the stability of mine openings. Roof supports are used to help stabilize these openings, but their performance characteristics must be properly matched to the loading environment and ground behavior if they are to succeed. Roof supports include both intrinsic supports, such as roof bolts, and standing supports. The key characteristics of any support include its maximum load-carrying capacity, stiffness, and residual strength. Other important factors are the timing of installation, the stability of the support as it is loaded, and the capability of the support system to provide skin control. This paper explains in practical terms how supports work and the important factors in ensuring that a good support design and application strategy are developed.

Jan 10, 2000

By George H. Holmes

Beryllium deposits in the northern Virgin Mountains , Clark County , Nev . , and Mohave County , Ariz . , about 70 miles northeast of Las Vegas , were investigated by the Bureau of Mines . The investigation indicated a widespread occurrence of beryllium- bearing pegmatites within an extensive belt of mica - schist . Several deposits with significant beryllium mineral concentrations were encountered . Only a few of the samples analyzed contained more than 1 percent beryllium oxide ( BeO ) ; in many of the samples , no beryllium was reported . The average tenor of samples from the more important occurrences was 0.25 percent BeO . Chrysoberyl is the predominant beryllium mineral in the pegmatite sills ; beryl predominates in the more massive bodies . Minute quantities of cesium and lithium minerals also occur , but no columbium , tantalum , or other rare minerals were found . Ore dressing tests on a composite sample containing 0.28 percent BeO which was representative of the pegmatite sills , indicated an 85 percent recovery of the chrysoberyl ( 70 percent recovery of total BeO ) by gravity concentration in a concentrate containing 17.6 percent BeO .

Jan 1, 1964

By Kenneth J. Miner

Pittsburgh bed and Lower Freeport bed coals were tested in the U.S. Bureau of Mines two-stage froth flotation pilot plant, which utilizes a new flotation process to remove pyritic sulfur. The process consists of a first-stage coal flotation step to remove coarse, free pyrite and other refuse in the tailings. The clean coal froth concentrate is then repulped and treated with a coal depressant, a pyrite collector, and a frother to selectively float the remaining pyrite in a second stage. Results in the pilot plant were excellent, comparing well with those obtained in laboratory batch tests. That is, about 70 percent of the pyrite present in the Pittsburgh bed coal and about 90 percent of the pyrite present in the Lower Freeport bed coal were removed with excellent final clean coal recoveries.

Jan 1, 1973

By J. J. Demeter

As part of its work on converting coal to fluid fuels, the Federal Bureau of Mines has been studying the synthesis of liquid fuels from carbon monoxide and hydrogen by Fischer-Tropsch synthesis. A fluidized bed of nitrided, fused-iron catalyst has been operated successfully to produce high yields of oxygenated compounds. Trouble-free operation continued for over 800 hours, and the test was terminated voluntarily. About 85 percent of the fresh feed was converted when the unit was operated at a space velocity of 500 hr.-1, a 12:1 recycle-to-fresh-feed-gas ratio, a 300-p. s. i. g. pressure, and a temperature of 252° C. When operating at a fresh-feed-gas space velocity of 1,000 hr.-l and a 9:1 ratio of recycle to fresh gas, conversion of fresh feed was 68 percent, and the product yield was 235.9 grams per cubic meter of synthesis gas converted. The oxygenate and C5 and heavier hydrocarbon yield was 110.6 grams per cubic meter of gas converted, 83 percent of this was oxygenates. The atom ratio of N:Fe of the catalyst, initially 0.455, decreased to 0.288 by the end of the 800-hour experiment. Nevertheless, the yield of oxygenated compounds per cubic meter of H2 + CO converted at the end of the run was approximately the same as that obtained 500 hours earlier with identical operating conditions. X-ray analysis of the discharged catalyst indicated that only ?-iron carbonitride was present. Sieve analysis of the discharged catalyst indicated that only 2 percent of fines was produced during the reduction, nitriding, and synthesis.

Jan 1, 1959

By Charles L. Kimbell

Comprehensive data on market prices for crude minerals and mineral products for the world as a whole do not exist, and even the data that are available are not necessarily compatible between countries, particularly between the market economy countries and the centrally planned economy countries. Further, it should be evident that the actual delivered price for a small quantity of any specific commodity at some point substantially removed from a production facility or a seacoast port will differ appreciably from that for a large volume of the same product at or near its production source or a major import center. Nevertheless, the regularly published prices of selected major mineral commodities in key market areas can be regarded as indicative of general world price trends.

Jan 1, 1992

By Henry H. Ginsberg

The effectiveness of 0.01 pct. molybdenum, as ammonium molybdate impregnated on coal, on the hydrogenation of a high-volatile bituminous C coal at 8,000 p.s.i.g. and 460° to 480° C. has been studied in a pilot plant by the Federal Bureau of Mines. Under these conditions, the Bureau obtained 98 to 99 pct. conversion5/ of coal to liquids and gases at throughputs of 29 to 101 lb. of m.a.f. coal per cubic foot of reaction space per hour. At 460° C. the indicated yield of oil ranged from 63 pct. (based on m.a.f. coal) at a throughput of 35 lb./c.f.h. (pounds per cubic foot per hour) to 68.5 pct. at a throughput of 58 lb./c.f.h., and the yield of gaseous hydro-carbons ranged from 25.5 to 19 pct. at the same throughputs. The maximum measured yield of oil boiling under 325° C. was 47 pct.

Jan 1, 1960

By Dennis J. Grigal

The objective of this contract was to monitor operating conditions of, four flooded, fibrous-bed filter panels used during normal underground mining operation and to analyse clogging and structural problems. After observing structural and clogging problems and conducting laboratory and field tests, a final, Flooded, fibrous-bed filter design which minimizes clogging and structural problems was recommended to the Bureau of Mines. This report also describes the dust sampling procedures used to determine the dust concentration at the flooded, fibrous-bed scrubber intake duct.

Jan 1, 1979

By R. A. Friedel, J. L. Shultz, A. G. Sharkey

The purpose of this investigation was to study the primary materials associated with the coal structure . Mass spectrometric techniques can be useful in studying the chemical structure of coal and various high- molecularweight materials derived from coal . Investigations of pyrolysis products and extracts of coal , and also whole coal , showed : 1. Aromatic hydrocarbons obtained by the vacuum pyrolysis of coal below 300 ° C possibly were sorbed material rather than decomposition products . 2 . 2 . Thirteen structural types having molecular weights from 78 to 400 were identified in pyridine extracts constituting one - quarter or more of the coal by weight . 3. Material extracted at room temperature with a methanol - benzene solvent and a vacuum pyrolysis condensate obtained at 450 ° C contain similar components . The extract and the condensate have approximately the same average molecular weights ( 200-300 ) . 4. Material extracted from coal at room temperature is altered even by mild thermal treatment . 5. Changes in various alkyl series occurring in thermally treated coal extracts can be followed quantitatively . 6. Similarities in the spectra of coal and graphite were indicated in an investigation using a mass spectrometer equipped with a spark source . Determinations on a coal - ash sample by this technique showed good agreement with data obtained by emission spectroscopy .

Jan 1, 1963

By Louis A. Panek

Tests of mine-roof models in a centrifuge show that the suspension effect due to bolting a horizontally bedded mine roof with frictionless surfaces of contact between beds depends principally on the number of bolted beds and their relative flexural rigidities, provided that sufficient bolt tension is exerted to prevent strata separations at the bolt locations. Strata separations tend to occur in the unbolted roof mainly because the beds have unequal thicknesses. "Suspension effect" refers to the transfer of part of the weight of weaker or thinner beds to the flexurally more rigid beds by roof bolts or by any other means. The factors investigated were number of beds in the bolted unit, bed thickness, modulus of elasticity of beds, length of bolts, spacing of bolts across and along the opening, bolt load, and intensity of roof load. The general principles of behavior of the bolted roof beds are explained by an approximate theory. Model test data are used to validate the theory and to obtain an expression for the "suspension efficiency". As the suspension effect actually observed in the models is smaller than that predicted by the approximate theory, the suspension efficiency in general is less than unity. Mathematical expressions are obtained for (1) the change in roof bending stress due to the suspension effect, which is needed for design of a roof-bolting system, (2) the change of roof deflection due to the suspension effect, which may be useful for evaluating the effectiveness of a roof-bolting system, and (3) the bolt load or pre-load that is required to achieve the desired reinforcing effect.

Jan 1, 1962

By Thomas L. Vandergrift

This U. S. Bureau of Mines (USBM) report evaluates three stress-transfer-modification concepts for their potential in reducing longwall gate road stresses and closures. In each of the three concepts - packwalling, gob infilling, and entry filling -support structures are constructed on the headgate side of the panel parallel with or inby the face line. When the headgate becomes the tailgate of the adjacent panel, these structures are in place to accept stresses transferred from the mined-out panel. Using the USBM nonlinear boundary-element program MULSIM/NL, baseline models of typical longwall stress transfer behavior were developed for both intermediate depth and deep mining conditions. These models were verified by comparing model results with field measurements and observations. The stress-transfer-modification concepts were then incorporated into the deep baseline model to quantify the effects of each concept on tailgate closure. Modeling results indicated that entry filling is the most effective concept in reducing tailgate escapeway closure. Using only 18 m3 of a weak fill per meter of face advance (7.3 yd3 per ft of face advance), tailgate escapeway closure was reduced by 33%. By improving the quality of the fill, similar results were achieved using 50% less volume.

Jan 1, 2010

By J. K. Richmond

Early research on coal dust explosions by the Federal Bureau of Mines and in other countries is reviewed to examine the effect of a single inhibitor, rock dust, on the explosion limits of coal dust. The parameters studied in this research included coal dust fineness, volatile content, and type of initiation. This research resulted in appropriate safety regulations in the respective countries. Also reported are the results of recent research in the Experimental Mine of the Bureau of Mines to investigate in detail the limits of coal dust explosions; the research used three types of coal with rock dust added as the independent variable. New experimental techniques and new criteria for defining propagation/nonpropagation were applied to the experiments. Also, a limit explosion propagation model is proposed based on the assumption of rapid devolatilization of the coal particles, with the subsequent combustion of the evolved volatile products contributing primarily to the propagation of the explosions. The model assumes also that the resultant char acts mainly as an inert diluent similar to the rock dust. The model also suggests that the function of stronger initiation is mostly to lift more dust from the mine surfaces.

Jan 1, 1975

By McHenry Mosier

Mercury is one of the strategic metals the supply of which has been raised from critical uncertainty to more than enough for essential demands. Work by the Bureau of Mines has contributes substantially to increased production of mercury in the United States and to consequent accumulation of Governments stock. Other contributing factors were higher prices for mercury and Government loans to operators. The Bureau has undertaken 15 exploration projects, 13 of which have been completed. This work comprised 40,307 feet of drilling arid 35,082 linear feet of sure ace trenching and has indicated commercial ore containing 37,400 flasks of mercury and marginal ore contain¬ing 29,200 flasks - a total of 66,600 flask , equivalent, respectively, to domestic production at 50,000 flasks per year for 9 months , 7 months, and 16 months. Early in 1944, as Government stocks had become adequate, domestic production was gradually curtailed cancellation of Government contracts for the purchase of mercury and Government control of labor and operating supplies.

Jan 1, 1944