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By M. L. Skow, Maurice Deul, M. G. Zabetakis

This Bureau of Mines report presents a brief summary of the explosion trends in United States coal mines for the past 160 years. These trends show that in spite of the overall improvements in mine safety, the number of fatalities from ignitions of methane has actually increased in recent years. Suggestions are made of procedures that can be utilized to reverse this trend.

Jan 1, 1972

By N. A. Gokcen

Equilibrium partial pressures of gaseous HCl and H2O over aqueous binary and ternary solutions of HCl and AICls were calculated or estimated in the range of 20° to 110° C, and up to saturation with AlC13?6H2O. The results were extended to solutions containing less than 10 wt-pct FeCl3 by assuming that FeCl3 and AIC13 are equivalent on the molar basis, since both salts have trivalent cations with a cammon anion. The ionic activity coefficient of HCl and the equilibrium constant for dissolution of gaseous HCl were also computed. This research is part of the effort by the Bureau of Mines, U.S. Department of the Interior, to provide thermodynamic data to expand the technology base relevant to the extraction of alumina from nonbauxitic domestic raw materials.

Jan 1, 1980

By N. E. Hanna

The effect of small percentages of sodium chloride on the incendivity of permissible explosives was studied by the Bruceton up-and-down technique in gallery tests. Both the reduction in incendivity achieved by addition of sodium chloride and application of the test method to explosives evaluation are discussed. It is demonstrated that the up-and-down technique in gallery testing is suitable for distinguishing differences in incendivity between different explosive compositions and between lots of the same composition. The study also shows that addition of relatively small quantities of sodium chloride tends to reduce the incendivity of explosives to firedamp, but addition of sodium chloride cannot insure reduced incendivity. Any improvement attributable to the salt can be counteracted by undefined variations in the explosive. The need for experimental investigations of a number of factors that may affect the safety of permissible explosives is emphasized. ACKNOWLEDGMENTS Grateful acknowledgment is made of the assistance of Roy L. Grant in analyzing for normality of distribution of the data obtained by the up-and-down methods and to Harold E. Tubbs for numerous calculations.

Jan 1, 1959

By F. W. Cox

Exhaust emissions were measured from 25 aircraft turbine engines using Jet A fuel. Analytical apparatus, procedures, and results are described. Carbon monoxide, carbon dioxide, nitric oxide, nitrogen dioxide, and aldehydes were measured at engine operating modes representing power levels used in airline operation. Carbon monoxide, hydrocarbon, and aldehyde emissions were highest at idle and lowest at takeoff; oxides of nitrogen were lowest at idle and highest at takeoff. Of the total oxides of nitrogen emitted, nitrogen dioxide constituted from 10 to 100 pct, depending on the exhaust gas temperature. Engines retrofitted with smoke-reducing burner cans produced less carbon monoxide, hydrocarbon, and aldehyde emissions, and slightly more oxides of nitrogen then engines with standard burner cans.

Jan 1, 1972

By R. F. Abernethy

A small-scale method was developed for determining the free-swelling index of coal samples of limited quantity, especially the macerals. Results of a series of tests using a 0.3-gram sample correlated well with those by the standard method using a 1-gram sample. The standard and small-scale methods are modified to give unrestricted swelling for those coals having swelling index numbers above 7.

Jan 1, 1971

By H. Schultz

Urban refuse that was mechanically separated at the U S Bureau of Mines pilot plant in College Park, Md., was successfully evaluated for its fuel values using standard coal analysis methods. Analyses performed on refuse samples taken from five sample points included moisture, ash, sulfur, chlorine, and heating value. It was recommended that characterization of the combustible portion of urban refuse by standard coal analysis procedures should be widely adopted.

Jan 1, 1975

By J. H. Maysilles

The Bureau of Mines is examining a variety of low-grade uranium ores because projections indicate that an appreciable percentage of future U.S. uranium production will be derived from resources containing 0.01 to 0.1 percent U308. One possible source is represented by a granitic material from Wyoming; the available samples contained 0.06 and 0.12 percent U308. Tests were conducted to explore the general leaching characteristics of this potential resource. The material responded to both acidic and alkaline leaching techniques. Conventional acid leaching extracted 93 percent of the uranium in 18 hours; the required acid addition was 50 to 100 pounds of H2S04 per ton of ore, and the oxidant addition was 3 pounds of NaCl03 per ton of ore. The acid consumption continues after maximum uranium recovery has been reached; this effect may complicate heap or in situ leaching with acidic solutions. Some variation in reagent requirements was noted between the two ore samples. Conventional carbonate leaching with strong solutions at 85° C extracted 94 percent of the uranium in 24 hours. These granitic materials also showed some response to dilute carbonate solutions, and the results suggest that the material may be chemically amenable to heap or in situ leaching with dilute carbonate solutions.

Jan 1, 1977

By Edward F. Divers

This Bureau of Mines report describes the results of a program to develop small, rugged scrubbers with high dust collection efficiency for use in under-ground coal mines. The Bureau's Pittsburgh (Pa.) Research Center has developed and assisted in the development of several types of improved scrubbers that are especially suitable for various underground mining applications. Research efforts concentrated on reducing the size, power, and water consumption of these scrubbers, while optimizing their dust collection efficiency. Fractional dust collection efficiency, air volumetric range, size, power, water consumption, and application guidelines for each type are described. Air pressure differentials ranged between 2-and 3D-inches water column (wc). The dust collection efficiency of six scrubbers--a venturi, two flooded-fibrous-bed, a venturi-impaction plate, a wetted-fan, and a rotating flooded-bed--were compared. The rotating flooded-fibrous-bed and the stationary flooded-fibrous-bed scrubbers showed the highest coal dust collection efficiency. Test results show that these scrubbers can generally achieve respirable size coal dust collection efficiencies in the high 90-pct range required to reduce both long-(8-hour) and short-term coal mine dust concentrations below Federal requirements.

Jan 1, 1979

By Eric E. Cather

In 1981 the U.S. Bureau of Mines and U.S. Geological Survey conducted a mineral survey of the 5,100 acre (2,065 ha) Rubicon RARE II area (No. 5026) in the El Dorado National Forest (fig. 1). Work by the Bureau of Mines indicates that potential for mineral resources in the area is low. Samples from small gravel deposits along the Rubicon River and from favorable structures in the area contained smart amounts of economic minerals. A Tertiary river channel near the north area boundary contains gold values as much as $137.60 per cu yd ($180 per cu m) [(gold at $400 per troy oz ($12.86 per g)]. The channel does not cross the study area. Energy resource potential, including oil, gas, or geothermal, does not exist in this geologic environment.

Jan 1, 1982

By R. V. Ramani, R. Stefanko, G. W. Luxbacher

The Federal Coal Mine Health and Safety Act of 1969 has dictated major changes in mine ventilation with regard to both air quantity and quality. Requirements have also been placed on the ventilation of beltlines, gob and face areas, and air velocities on trolley haulage roads are limited. Escapeways, separate from trolley haulage roads and on an intake split of air, must be maintained continuous to the surface. These and other similar requirements have not only precipitated several modifications to existing ventilation systems but also have greatly increased the complexities of new mine ventilation planning. It is apparent that the use of computers in ventilation system analysis and design is a necessity. SUMMARY Although computer oriented analysis of mine ventilation systems was introduced over two decades ago, it has yet to receive widespread acceptance in the United States. Central to this problem is the fact that, while many computer programs for network analysis have been developed, no attention has been paid to the development of computer input data. Consequently, without this foundation, program applications have been infrequent. This thesis has directly attacked this problem and has presented all pertinent information basic to the development of good computer input data. The areas that were covered include quantity measurement, pressure measurement, fan testing, survey data balancing, and the development of a network schematic from the ventilation survey results. These discussions on data collection and the corresponding reduction to computer coding have been illustrated by an application of a ventilation simulation program to an existing mine in Southwestern Pennsylvania. The use of a ventilation

Jan 1, 1977

By Oliver C. Fursman

The Bureau of Mines undertook this investigation to study methods of utilizing red mud residues from production of alumina from bauxite. Pilot-plant tests were conducted using Jamaican and Surinam red muds. Both the carbon-lime-soda sinter process and electric-arc smelting with coke and limestone were employed to recover iron and alumina. Alumina recoveries of 85 to 90 percent were obtained by the sinter process; although iron recovery was about 80 percent, the magnetic product was finely divided and difficult to separate from the gangue. Smelting red muds in the electric-arc furnace produced a pig iron with 98-percent recovery of iron; up to 84 percent of the A1203 was recovered by leaching the calcium aluminate slag with Na2C03 solution. A titania product assaying 96 percent TiO2 was recovered from the nonmagnetic portion of Surinam red mud sinter by extraction with H2SO4. Leached calcium aluminate slags and brown mud (from the combination Bayer process) are possible raw materials in the manufacture of portland cement.

Jan 1, 1970

By Jacqueline A. McClaskey

The U.S. Bureau of Mines (USBM) Information and Analysis Directorate collects worldwide data on virtually every commercially important non fuel mineral commodity. These data form the base for tracking and assessing the health of the minerals sector of the U. S. economy. The USBM's data collection activity was instituted by the 47th Congress in an appropriations act of August 7, 1882 (22 Stat. 329), which placed the collection of mineral statistics on an annual basis. The most recent authority for the USBM survey activity is the National Materials and Minerals Policy, Research and Development Act of 1980 (Public Law 96-479, 96th Congress). This act strengthens protection for proprietary data provided to the U.S. Department of the Interior by persons or firms engaged in any phase of mineral or mineral-material production or consumption.

Jan 1, 1992

By P. G. Clites

This study was conducted to determine the patterns of heat transfer to water-cooled copper crucibles during vacuum arc melting. Values of heat flux from the ingot to the crucible were determined during nonconsumable electrode vacuum arc melting of zirconium and during consumable electrode vacuum arc melting of titanium) zirconium) and steel. The results of these studies con-firm the existence of a high thermal resistance between the ingot and the crucible wall which results from the shrinkage of the ingot as the metal solidifies. Maximum heat flux occurs near the top of the ingot where maximum values of heat flux of 1.4 X 106 Btu/ft2 hr were observed during small-scale consumable electrode arc melting of zirconium and titanium. The maximum heat flux for consumable electrode arc melting of 8-inch-diameter ingots was 0.5 X 106 Btu/ft2 hr. The effects of electrode material) electrode diameter) arc current) and arc potential on heat flux from the ingot to the crucible were studied. Data were also obtained on crucible wall temperatures and on the effect of very narrow annular water jackets.

Jan 1, 1967

By M. M. Tilman

The Bureau of Mines conducted research into the dispersion strengthening of lead by the coprecipitation method. Commercially available reagents in water solutions were reacted to form homogeneous precipitates of lead and aluminum compounds. The resulting precipitates were roasted to oxides and reduced in hydrogen to form mixtures of lead powder and alumina. The powders were isostatically pressed into billets which were extruded into rods. The rods were rolled into strip to provide material for testing. Alloys containing 0.5, 1, 2, and 3 nominal volume-percent A1203 were tested in short-time tensile tests and in tensile creep tests. An alloy of Pb-3 volume-percent A1203 exhibited an average tensile strength of 8,570 psi after rolling to 75-percent reduction at 125° C but had no measurable elongation. Alloys of lower A1203 content provided a better compromise between tensile strength and ductility. For example, an alloy of Pb-0.5 volume-percent A1203 had an average tensile strength of 6,590 psi with 9-percent elongation after rolling to 75-percent reduction at 125° C. Creep rates of dispersion-strengthened Pb-A1203 alloys were below 1 percent in 10,000 hours at stresses of 2,000 to 4,000 psi.

Jan 1, 1971

By Albert W. Deurbrouck

This report describes the preparation characteristics of the Pittsburgh and Upper Freeport coalbeds in Hancock , Brooke , Ohio , and Marshall Counties , W. Va . Over 4.5 million tons of coal was produced in these four counties in 1962. Most of this production came from the Pittsburgh coalbed . Twelve coal samples were collected for this study , 11 from the Pittsburgh bed and 1 from the Lower Freeport bed . Two of these samples could be upgraded to produce metallurgical - grade coal . The sulfur content of the Pittsburgh- bed coals was generally excessive --as high as 4.9 percent in the raw coal and 3.19 percent in the float 1.30 specific gravity fraction . The rank of the coals in this area ranges from high-volatile A to high-volatile B bituminous .

Jan 1, 1964

By R. F. Tenney

No detailed information has been published heretofore on the performance of small industrial-type anthracite stokers in building-heating service, apparently because of the difficulty of comparing the performance of one unit with that of another over an entire season's operation. Studies of competitive heating fuels have been similarly handicapped, and attempts to compare fuels are seldom technically sound in this investigation, the performance of a 60-in. Losch4 stoker burning rice-size anthracite in a standard commercial boiler was observed during a 4-month winter-spring season. It was used to heat two buildings at the Bureau of Mines' Anthracite Research Center at Schuylkill Haven, Pa., with the customary type of automatic pressure-range control. Attendance was limited to inspecting, fuel weighing, data recording, and ash removal. Results were computed daily and grouped by weekly periods to minimize daily irregularities. The same stoker-boiler unit had already been tested in a series of American Society of Mechanical Engineers (ASME) test code runs, with the stoker running continuously and with other conditions well stabilized A comparison of results from the code test and the building-heating tests provided information not available in the past for a single stoker unit, assisted in analyzing heat losses not computable in a cyclic operation, and established a basis for evaluating stoker performance in heating service.

Jan 1, 1963

By J. J. Hoeppner

Accurate determination of moisture in coals of various ranks has long been a subject of intensive investigation. Excellent reviews of methods developed over many years are given by Brown (9)4/ and, with experimental comparisons, by Goodman, Gomez, and Parry (11). As pointed out in these and other writings, one of the principal difficulties in assigning absolute merit to one or another procedure is the multiplicity of conditions under which water may exist in coal and the difficulties involved in obtaining sharp separation and distinction between these classes. Gauger (10) states: Water recoverable from coal is obtained from the following sources: (1) Decomposition of organic molecules (sometimes called combined water), (2) surface adsorbed water, (3) capillary condensed water, (4) dissolved water, and (5) water of hydration of inorganic constituents of the coal.

Jan 1, 1956

The extrapolation of results from reconstructed laboratory soil columns to field conditions is difficult because of the limitations of laboratory experiments. Permeability and elution tests performed in the laboratory differed from the natural state in that the soil was sieved through 1/4 inch screen to remove large stones and roots, its density was controlled by tamping the soil into two-inch I.D. tubes instead of normal weathering, and water and latex were applied with a constant head of liquid. Tube wall effects are important in interpreting data. Conversely, interpretation of field results were confounded by non-homogeneities within the sample tested, a soil profile with gradation of permeability and density with depth, and uncontrolled weather conditions and seasonal changes that affected the results. Nevertheless, both laboratory and field tests showed that a specific latex did perform as a soil sealant. In view of these facts a soil box experiment was designed to overcome some of the disadvantages associated with the small laboratory soil columns and the field experiments. Two wood soil boxes 5 ft x 5 ft x 5 ft were built in the greenhouse at the Uniroyal Research Center. They were lined with plastic PVC sheeting provided with tubes every six inches of depth on one side of each box to measure water removal rates under saturated conditions. Tensiometer gauges were placed at depths of 6, 12, 18, 24, 36 and 48 inches and Bouyoucos blocs and resistance thermometers were positioned at 6, 24 and 48 inch depths. Each box was filled with a uniform sub-soil obtained from Ogdensburg, N. J. The texture of this soil was determined to be a sandy loam by the ASTM Hydrometer method, as shown below: [ ] The boxes were thoroughly wetted by sprinkling to abet settling and allowed to dry by draining to check seepage ports and functioning of tensiometers.

Jan 1, 1972

By R. Van A. Mills

This preliminary paper is intended to answer briefly some of the inquiries coning to the Bureau of Mines regarding the so-called "paraffining", of oil wells and methods of preventing and remedying that trouble. The increased difficulties in operation and the losses of production caused by the deposition of gummy and waxy hydrocarbons, commonly called paraffin, in the wells, tubing, other pumping equipment, and in the pores of the productive sands, have long been recognized but the trouble has not been overcome. The nature and causes of the trouble, together with some of the possible methods by which it may be diminished or overcome, are outlined below. Character of the Peraffining Materials. The so-called paraffin that collects in oil wells end in the pores of the oil-producing sands immediately around the wells, is generally made up of amorphous wax or uncracked paraffin, asphalt, or other gummy hydrocarbons mixed with more or lees water, oil, and inorganic silt. Some of the samples of this "paraffin" collected from oil wells in different fields and examined by the Bureau of Mines contain as mach as 20 per cent by weight of water and inorganic silt, whereas other samples are composed entirely of waxy hydrocarbons and oil. The inorganic silt accompanying this "paraffin" is mostly fine sand, clayey materials, common salt and finely disseminated precipitates of calcium and magnesium carbonates. Sulphates of calcium, barium, and strontium are less common constituents of the "paraffin."

Jan 1, 1923

By W. A. Haley

The purpose of this investigation was to develop and improve mining methods for mining thin coal beds, to increase productivity, and to increase the recovery of coal. German coal planers and a modified longwall system of mining were introduced into American mines and are bringing about increased productivity and better recovery as compared with the conventional methods displaced. Since the first installation, 4 additional planers have been purchased by coal companies and over 1-1/2 mil¬lion tons of coal has been mined by them, using the modified longwall mining method. INTRODUCTION Except from 1932 to 1934, the growth of mechanical loading in underground bituminous-coal and lignite mines in the United States has increased steadily. The amount of coal loaded mechanically in underground mines has increased from 0.3 percent in 1923 to 79.6 percent of the total underground production in 1953.3/ The use of new and improved mining machines and auxiliary equipment, together with new techniques in mining methods, usually has resulted in increased productivity.

Jan 1, 1957