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By Charles Vaught, Henry J. Kellner, Michael J. Brnich, Henry P. Cole, William J. Wiehagen

In 1985, U.S. Bureau of Mines and University of Kentucky researchers began a series of studies relating to self-contained self-rescuer (SCSR) donning proficiency. During the next 5 years investigators examined a number of factors that have a bearing upon miners' ability to put on and use the apparatus in an emergency: the procedure being taught; availability and utilization of training models; opportunities to practice; hygiene; and on-the-job training. This report presents an overview of that research. It is concluded that companies should adopt a hands-on training protocol that allows them to integrate SCSR donning practice into other workplace routines such as fire drills.

Jan 1, 1993

By C. P. Fang, V. A. Marple, K. L. Rubow, P. H. McMurry

"It has been known for some time that sizes of aqueous particles may be affected by flow-induced relative humidity (RH) changes. The RH of air flowing through an impactor decreases as a result of pressure drop through the impactor and increases because of aerodynamic cooling within the high-speed jets, as illustrated in Figure 1. Because the sizes of aqueous particles depend on RH, the impaction stage on which such particles are collected may be different from the stage where they ought to be col¬lected, based on the particle size at the sampler inlet.Fuchs (1980) reviewed literature on water vapor condensation in impactors. The reviewed impactors operated at jet velocities of 100-250 m/s. Particle size increases ow¬ing to water vapor condensation were found in all cases. In one case (Khorguani et al., 1970), it was found that very small droplets (Dp <_ 0.02 um) containing sodium chloride and silver iodide were collected in an impactor with a cut point of 0.32 µm and a jet velocity of 100 m/s. Fuchs believed that such particles could not be captured in an impactor without having been enlarged by condensation. Winkler (1974) sampled at¬mospheric dust with a rectangular nozzle impactor that had a nozzle cross section of 0.3 x 15 mm, a cut size of 0.4 um, and an average jet velocity of 100 m/s. No adhesive was used on the impaction plate. The collection efficiency increased as air humidity was increased from 20% to 100%. The effect was especially noticeable in the increased collection efficiency for hygroscopic particles, and was attributed to condensation.Extensive theoretical and experimental research work on the distortion of the particle size distributions in impactors was done by Biswas and coworkers (1985, 1987). The impactors employed in the study were a low-pressure impactor with high jet velocity stages (Hering et al., 1978, 1979) and a conventional six-stage impactor, Sierra's model 226, operated in the incompressible regime. Ammonium sulfate aerosols were chosen for the study. In the low-pressure impactor, an orifice operating at a Mach number of 1 causes a sudden pressure drop, significantly reducing the RH in the next two stages (stages 5 and 6). This results in a 0.15-um diameter ammonium sulfate droplet shrinking to about 0.07 um at stage 5 when the inlet RH is 95%. In stage 7, the tempera¬ture drop is considerable because the jet speed is sonic. For an inlet RH of 95%, a 0.03 um droplet grows to about 0.06 um. However, the same size droplet at an inlet RH of 25% grows to only 0.04 um. For the Sierra model 226 cascade impactor that is operated with a Mach number of 0.27 at the last stage (stage VI), it was found that for an inlet RH of about 67%, particle growth would occur in stage VI. At 80% RH, both stages V and VI were affected. Biswas et al. (1987) stated that Mach number alone does not determine the size biasing; the type of aerosol, the inlet conditions, the temperature and pressure ratio, and the impactor geometry (throat length, jet-to-plate distance, etc.) must be considered for each stage in evaluating the distortion of the particle size distribution."

Mar 1, 1992

By V. A. Nieberlein

The purpose of this investigation is to determine the reserves of columbium (niobium) minerals in Arkansas and to develop metallurgical methods for concentrating the minerals and extracting the metal. The columbium resources of central Arkansas were explored by drilling and trenching, and a number of samples were taken. On the basis of this exploration the known reserves of the metal were estimated to be over 78,000,000 pounds. The reserves could possibly be extended by additional exploration to 150,000,000 pounds.

Jan 1, 1954

By W. D. Mcmillan

Although the Shafter district of Presidio County, Tex., is principally renowned for silver production from the Presidio mine, the occurrence of lead-zinc ores in the western part of the district has been known for at least 50 years, and there has been some production. An area of about 3 square miles in the vicinity of an extending westward from the Presidio mine was investigated in detail by C. P. Ross of the Federal Geological Survey in 1934. In the fall of 1943, A. B. Needham, an engineer of the Bureau of Mines, called the attention of the Geological Survey to the area west of that included in Ross&apos;s map, and requested a detailed investigation of that area by the Survey in advance of development by the Bureau of Mines. After a brief reconnaissance by the Survey in the spring of 1944, detailed studies were made by Federal geologists in the summer of 1944, during which about 450 acres were surveyed, on a scale of 1 inch to 100 feet. Recommendations for the exploration of certain parts of the area were made in the accompanying report.

Jan 1, 1949

By M. J. Ackerman

This study was undertaken to make a comparison between the cost of mining coal under roof bolt and under conventional timber methods of roof support. Studies were made at 14 mines in Pennsylvania, eastern Ohio, and northern and southern West Virginia. At each mine data were obtained for sections of the mine where the physical conditions, mining equipment, and mining systems were similar. Coal, recognized as one of the basic industrial fuels, is very competitive with other fuels, and management, in order to protect and enlarge its market, must be continually alert to find more efficient methods of production. Continuous production of coal is desired by all operators but never obtained. In mechanized mining the performance and production vary with operating time, which can be interrupted by many variable factors, such as condition of the roof, method of roof support, condition of equipment, water, ventilation, power, transportation, efficiency of operating crew, and supervision.

Jan 1, 1961

By G. R. Strimbeck

The Federal Bureau of Mines has been developing processes for producing synthesis gas directly from coal, oxygen, and superheated steam. An atmospheric-pressure pilot plant was constructed and operated to: 1. Determine the operability of the plant for gasifying coals of different ranks under various operating conditions. Listed in decreasing order of rank, these coals included a Pennsylvania anthracite, a bituminous A coal from the Sewickley bed, West Virginia, and a subbituminous C coal mined in the Lake de Smet region of Wyoming. 2. Determine the effect of varying operating conditions on: (a) Standard cubic feet (std.c.f.) of oxygen and pounds of coal of different rank required to make M std.c.f. of product gas (carbon monoxide plus hydrogen); (b) carbon gasified, percent; (c) exit-gas temperature, degrees F.; and (d) heat loss, B.t.u. per pound coal. 3. Compare the gasification characteristics, indicated in item 2, of coals of different rank: Bituminous A, anthracite, and subbiturninous C. 4. Determine the concentration of dust in the gases produced and the efficiency of dust removal, and investigate the relation between the sulfur content in the coals gasified and the gases produced.

Jan 1, 1960

By Eugene Frey

The Romur is one of several properties in the Copper Mountain mining district, Fremont County, Wyo., that contain scheelite deposits. The district lies on the southern slope of the Bridger Mountains, 18 miles northeast of Shoshoni and 15 miles from the rail point at Bonneville on the Chicago, Burlington & Quincy Railroad (figs. 1 and 2). The tungsten deposits occur in a zone of pre-Cambrian schists and gneisses that have been cut by numerous basic dikes and granite pegmatite dikes. Scheelite occurs in lenses and pods that lie parallel to the foliation and bedding in the metamorphic rocks. The more important deposits are found in a lime-silicate rock consisting primarily of zoisite but with small quantities of quartz and carbonate. Scheelite was found in December 1941, and the area was mapped by the U. S. Geological Survey early in 1942. In November 1942 the Bureau of Mines commenced work on the Stardust-Comet group for the purpose of developing reserves for war requirements. The initial work consisted of driving an alit in the ore zone a distance of 109 feet. This zone was sampled during the progress of the work, and subsequently surface and underground exposures on adjoining properties also were sampled (figs: 5, 6, 7, and 8). One hundred twenty-four samples were obtained. Sample and assay data are shown in tables 2, 3, and 4.

Jan 1, 1950

By O. C. Blade

A comparison of certain properties of the commercial aviation gasolines produced in the United States during October 1949, 1950, and 1951 is presented in table 1, the 1951 data being average values from tables 3 through 6 of the present report. Trends in the average values of certain characteristics of these fuels may be seen in figures 1 through 4 which also indicate the minimum and maximum values. As may be observed, with the exception of changes in kinematic viscosities, the properties of commercial aviation gasolines have not varied greatly during recent years. A list of aviation-gasoline survey reports published by the Bureau of Mines is given on page 6. A summary of the average values of the properties on jet fuels is shown in table 2.

Jan 1, 1952

By Ben E. Lindsly

The study of "bottom-hole samples follows in natural sequence the study of samples obtained under high pressures at the well heads of flowing wells. The principal object of this phase of gas-solubility research, started actively in January, 1930, was to gain a more accurate knowledge of the physical and chemical characteristics of the oil-gas mixtures that exist in natural reservoirs.. In possession of actual data regarding the condition of the oil; the quantity of gas liberated from solution upon dimunition of pressure; and the relative volumetric proportions of gas to oil at various pressures throughout the flow string in a well, it should be possible to predict, with a fair degree of accuracy, That physical changes these mixtures would undergo throughout the life of a pool. Such information not only is important in designing flow strings in flowing Tells but is important also in solving problems relating to pumping efficiency and the power required for pumping. Although certain fundamental data were obtained in the study of samples taken at the well head, "bottom-hole" samples are more representative of subsurface mixtures of oil and gas because they are obtained at reservoir temperatures, and before the oil has had the opportunity of intermingling with extraneous gas; that is, gas which either was not in solution originally, or which was liberated from solution at higher pressure, and later became mixed with the original undissolved gas.

Jan 1, 1933

By Mark S. Sanders

Based on laboratory tests and preliminary field tests of off-the-shelf steel toed rubber boots, a molded sole design was developed to provide increased traction over conventional calendared sole miners&apos; boots. The pattern provided sharp edges perpendicular to both lateral and fore-aft slip vectors. The sole was designed to reduce mud caking. An instep lace-up capability was added to better secure the foot inside the boot. A five month field evaluation compared the prototype boots to the boots the participants usually wear. Although objective slip and fall data showed no significant advantage for the prototype, subjective evaluations made by the participants indicated increased traction for the prototype boots. Approximately 75 percent preferred the prototype to their own boot. Approximately one-third used the lace-up capability. It was concluded that molded soles provide better traction than calendared soles for the underground mining environment.

Jan 1, 1982

By E. L. Garton

The United States Bureau of Mines has recently collected samples of crude petroleum from wells in the newly developed Joiner. Kilgore, and Longview fields of Rusk and Gregg Counties in the East Texas district, and from the Van field of the East Central district of Texas.

Jan 1, 1931

By John M. Gomes

A two-phase molten halide-silicate technique for extracting tungstic oxide (WO3) from scheelite (CaW04) and wolframite [(Fe, Mn)W04] was investigated. The halide phase extracted over 99 percent of the was, whereas the lower silicate phase retained about 90 percent of the calcium, iron, or manganese oxides. The most efficient extraction and separation of tungsten from scheelite was accomplished at 1,080° C in a molten system containing, in mole-percent, 9 calcium tungstate (CaW04), 42 sodium chloride (NaCl), 28 sodium fluoride (NaF), 17 sodium metasilicate (Na2SiO3), and 4 alumina (Al2O3). Wolframite was also treated at 1,0800°C; the molten system contained, in mole-percent, 11 (Fe, Mn)W04, 74 NaCl, and 15 Na2 SiO3.

Jan 1, 1968

By L. K. Weaver

The objective of this Bureau of Mines publication Is to present a nomograph that provides a fast, convenient method for estimating hydrocarbon lease bonus bids for offshore acreage in the Gulf of Mexico. Discounted cash flow analyses were computed from a model derived to show the costs necessary to explore, acquire, develop, produce, and abandon a 5,000-acre block of offshore acreage, and the estimated income from the sale of the hydrocarbons produced from the block. The range of the variables in the financial analyses used to construct the nomograph are prices of oil, $2.50 to $5.00; recoverable hydrocarbon reserves, 44,651,476 to 127,575,645 barrels; and discounted cash flow (DCF) rates of return, 5.0 to 57.2 percent. A total of 1,234 sets of DCF data were used to construct the nomograph. The range of bonus bids shown on the nomograph is from 2 to 90 million dollars ($400 to $18,000 per acre).

Jan 1, 1973

By Earl R. Maize

Epoxy and polyester-type resins were injected into coal-mine roof strata of the thick Freeport coal seam in Allegheny County, Pa., at test sites in roof that had been exposed several weeks, in newly exposed roof, and in strata over solid coal. Test results indicate that the method of strengthening bituminous-coal-mine roof by injecting a bonding material into the roof strata can be developed into a safe, efficient support system. If roof bonding will become a standardized method of roof support and reinforcement or if it can be effective when used with other types of roof support can be determined only by extensive experimentation in various coal beds. Observations and conclusions are shown at the end of this report.

Jan 1, 1959

By Frederick C. Trutt

A guide to the development and utilization of an interactive mine-power-system fault program (Z-bus by algorithm) is presented. Theoretical foundations, as well as implementation considerations are discussed with respect to the mine-power system. Alternative Kron reduction techniques are presented along with a triangular-storage method for storage conservation. Program capabilities include the analysis of balanced and unbalanced (line-to-line, line-to-ground, and line-to-line-to-ground) fault situations using symmetrical component theory. To account for phase shifting in delta-wye transformers and zero-sequence network constructions, transformer and load configurations are specified by the user. The positive-and zero-sequence connections needed for network conformity are automatically constructed with the required impedances.

Jan 1, 1979

By Errol D. Sehnke

This U.S. Bureau of Mines report provides detailed information on worldwide alumina production capacity by plant and country. The information was compiled from a variety of domestic and international sources and was based on information available to the Bureau through December 31, 1993. Capacity data represent announced installed and planned capacities and do not necessarily reflect a Bureau of Mines judgment of actual plant operating levels or timing of planned expansions, The year-end capacity is the ?nameplate" capacity or estimated production capacity, whichever is larger.

Jan 1, 1993

By John M. Gomes

Two molten salt systems were evaluated as electrolytes for the repetitive recovery of tungsten from tungsten oxide (W03) made by calcining commercial-grade ammonium paratungstate. Using a sodium chloride-sodium fluoride-potassium aluminum tetrafluoride electrolyte at 800° C, 1 pound of 99.8 percent tungsten was recovered for each 2.7 kilowatt-hours of energy consumed. The metal contained 1,100 ppm carbon, was in dendritic masses of spherical grains, and had an apparent bulk density of 5.41 g/cm3. T ngsten of 99.9 percent purity was won from a sodium pyrophosphate-sodium tetraborate-sodium chloride electrolyte at 1,000° C; 6.0 kilowatt-hours of energy was consumed for each pound of metal recovered. The metal contained 120 ppm carbon, was in dendritic masses of hexagonal acicular crystals, and had an apparent bulk density of 7.25 g/cm . Each metallic impurity--aluminum, calcium, copper, iron, nickel, and silicon--in the two tungsten products was 16 ppm or less.

Jan 1, 1966

By J. D. Ramsdell

The study described in this report was undertaken to obtain information on the character and effect of antimony additions to titanium. The availability of high-purity, low-hardness titanium metal, resulting from fused-salt electrorefining techniques, permitted a reassessment and evaluation of the physical behavior of titanium-antimony alloys. Alloys, based on several grades of titanium containing up to 10 percent antimony, were arc-melted and processed to sheet by hot and cold rolling. Properties and characteristics were evaluated by hardness tests, hot and cold rollability, annealing treatments, metallographic examination, and tensile tests.

Jan 1, 1960

By Ronald S. Conti

This U.S. Bureau of Mines report discusses the results of research conducted in the Bureau&apos;s experimental mine at Lake Lynn Laboratory on the response of fire sensors to simulated mine fires, which included (1) a slowly developing coal-conveyor belt fire, (2) a rapidly burning liquid fuel-belt fire, and (3) a liquid fuel-belt fire in the presence of diesel exhaust. During these tests, several mine fire sensors were evaluated with respect to sensor placement, spacing, and type. The data indicate that smoke sensors alarm several minutes before CO sensors do; and that, in the presence of diesel exhaust, a prototype diesel-discriminating smoke sensor can successfully function without being sensitive to the diesel contaminants. The vertical placement of sensors in the entry near the fire was also shown to be critical in terms of alarm times. Additional data showed that variations exist in response time and level of response for two brands of electrochemical CO sensor. Results also indicate that early detection of fires will improve the probability of miners&apos; escape, because of reduced smoke concentrations during the incipient stages of the fire.

Jan 1, 2010

By A. B. Needham

This report describes the exploration work done in 1941 in connection with the search for strategic minerals as authorized by the Strategic Materials Act approved by the President on June 7, 1939. It deals with the various manganese deposits and showings in the Tombstone mining district of Cochise County, Ariz. The exploration project comprised a study of the geology, mapping of the areas, and exploration of various mines and deposits by sampling old drifts, crosscuts, and scopes, supplemented by diamond drilling from underground stations. The Federal Government&apos;s manganese-purchasing programs have revived interest in occurrences such as the scattered deposits near Tombstone. Because of this, the Bureau of Mines project report on the Tombstone district, prepared originally in 1941 but not published, has been revised and now is being made public.

Jan 1, 1956