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By Harold L. Rhodes

The Bureau of Mines has developed a quantitative method to determine water vapor in helium in the range of 0.1 to 15 ppm by volume. This method uses the quantitative chemical reaction of H20 with CaH2, which produces 1 mole of hydrogen for each mole of H20 in the sample. A gas chromatograph is then used to determine the concentration of hydrogen in the product. The precision of the H20 analysis is ±0.05 ppm at a concentration of 1 ppm. This method is used to calibrate a commercial platinum-phosphorus pentoxide (Pt-P205) electrolytic water vapor analyzer that has an improved inlet system and digital voltmeter readout.

Jan 1, 1981

By Howard E. Parkinson, John N. Murphy

Abstract-Underground mines are typically extensive labyrinths that employ many people working over an area of many square miles; exten¬sive analysis of mine-communications systems has identified specific problem areas, in particular the excessive times required to locate key personnel underground, the inadequacy of existing phone systems in terms of capacity and privacy, and the inability to communicate with men on the move with wireless communications, as is taken for granted on the surface. A review is presented of the existing systems, the prob¬lem definition, and the various approaches that have been or are being investigated to solve these problems. Manuscript received June 8, 1977; revised August 28, 1977. The authors are with the Industrial Hazards and Communications group, Pittsburgh Mining and Safety Research Center, Bureau of Mines, U.S. Department of the Interior, Pittsburgh, PA 15213.

Aug 28, 1977

By Isaac A. Zlochower, Michael J. Sapko, Eric S. Weiss, Kenneth L. Cashdollar

This paper describes dust explosion research conducted in an experimental mine and in a 20-L laboratory chamber at the Pittsburgh Research Laboratory (PRL) of the National Institute for Occupational Safety and Health (NIOSH). The primary purpose of this research is to improve safety in mining, but the data are also useful to other industries that manufacture, process, or use combustible dusts. Explosion characteristics such as the minimum explosible concentration and the rock dust inerting requirements were measured for various combustible dusts from the mining industries. These dusts included bituminous coats, gilsonite, oil shales, and sulfide ores. The full-scale tests were conducted in the Lake Lynn experimental mine of NIOSH. The mine tests were initiated by a methane-air explosion at the face (closed end) that both entrained and ignited the dust. The laboratory-scale tests were conducted in the 20-L chamber using ignitors of various energies. One purpose of the laboratory and mine comparison is to determine the conditions under which the laboratory tests best simulate the full-scale tests. The results of this research showed relatively good agreement between the laboratory and the large-scale tests in determining explosion limits. Full-scale experiments in the experimental mine were also conducted to evaluate the explosion resistance characteristics of seals that are used to separate non-ventilated, inactive workings from active workings of a mine. Results of these explosion tests show significant increases in explosion overpressure due to added coal dust and indications of pressure piling.

By Manuel Gomez

A computerized, interpolative mapping technique based on the moving average method was shown to be adequate to estimate the between-drill-hole values of coal-seam variables. The forecasting of the spatial distribution of coal properties along the seam was of three kinds: (1) Estimation of the variable of interest on a regional basis from widely spaced sample points, (2) prediction of coal properties for product control from closely spaced data, and (3) prediction of coal properties for specified benches, or layers of the coal seam, from closely spaced sample points. Estimates obtained with the computerized, interpolative mapping procedure were useful in the delineation of seam thickness, elevation, and overburden and in the estimation of sulfur and ash concentrations during the early phases of exploration. This grid interpolation technique was found adequate to adjust between-drill-hole values for trends resulting from the combined effect of several variables on a measured response. This information, coupled with statistical and geologic data that can be obtained in the exploration phase of mining, enlarges the information base available for coal-mine development planning, energy forecasts, and environmental control associated with fossil fuel power generation.

Jan 1, 1972

By G. L. Cook

The design of a dual-inlet system for a Consolidated model 21-103C mass spectrometer is described in detail. The system permits both high-mass and low-mass samples to be run by using a single instrument. The difficulties of using a single instrument for both purposes are given and a method of minimizing these difficulties through the use of the present design is discussed, After examining the experience of five years of use, the conclusions are that the bimodal operation is practical and the low-mass analyses had nearly the same precision as before the modifications to the instrument were made. In 1951, O'Neal and Wier.5/ published the first description of the modifications made to a mass spectrometer so that the spectra of hydrocarbons with molecular weights up to 600 could be obtained. Further discussion of the equipment of O'Neal appeared in 1953.6/ Also, Brown, Melpolder, and Young7/ described a parallel inlet system designed to reduce sorption effects at room temperature.

Jan 1, 1960

By Stephen D. Cramer

The solubility of methane, carbon dioxide, and oxygen was measured in brines at temperatures from 0° to 300° as part of Federal Bureau of Mines research on the corrosion of metals in high-temperature geothermal and mineral processing environments. Solubilities were measured by the technique of extracting pure gas, dissolved at pressures where Henry's law was applicable, from known volumes of brine. The results were smoothed with respect to temperature. The solubility, expressed in terms of the Henry's law constant, reaches a maximum at temperatures ranging from 60° to 100° C for methane and oxygen, and from 160° to 170° C for carbon dioxide. The Henry's law constant increases, that is, gases are salted out of the brines, in the presence of dissolved salts. Salting-out coefficients are strongly dependent upon temperature. The temperature dependence of the Henry's law constant for geothermal brines is different from that for sodium chloride brines owing to the more complex chemistry of the geothermal brines. The solubility of oxygen and carbon dioxide in brines exposed to air saturated with water vapor and at a total pressure of 760 mm Hg is reported for temperatures from 0° C to the normal boiling point.

Jan 1, 1982

By L. J. Kane

Chemical processes using coal often require economical removal of dust from high-temperature gases. Laboratory-scale investigations by the Federal Bureau of Mines have shown that an aluminum silicate fiber is suitable for filtering dust from gases at 1,800° F. The effects of the bulk density of the filter, rate of gas-flow, concentration of dust in the filter, fiber diameter, depth of filter, and concentration of dust in the feed gas on removal efficiency, pressure drop, and capacity of the filter to hold dust were studied. The laboratory filters were difficult to construct because the fibers were longer than the tube diameter. This caused irregular distribution of fiber that permitted dust-laden gases to leak through channels developed in the filter. Leaks also formed between the filter and the tube wall, but this was minimized by improved filter design. However, edge leaks and leaks through channels in the filter probably would be insignificant in properly constructed filters of industrial size. As the concentration of dust in the filter increased, the efficiency of the low-density filters decreased, contrary to expectations, probably because a higher percentage of the dust passed through channels that developed in the filter. The efficiency of high-density filters, however, increased with the concentration of dust in the filter. Results indicate that loosely packed filters would have a longer life than tightly packed filters at the expense of efficiency. As regeneration or replacement of stationary filters is difficult and expensive, loose filters would be best for filtering gases containing much dust. Gases containing little dust may be cleaned with tightly packed filters to obtain higher efficiency. For either type of filter, precleaning with cyclone separators or other means is advisable.

Jan 1, 1960

By L. W. Brandt

As part of its objective to expand the body of mineral information as a basis for new technology, the Bureau of Mines conducted research on the fundamental behavior exhibited by phosphate clay waste in settling ponds. A semiempirical equation used to describe the compaction of ceramic powders in a single-acting die was applied to aqueous phosphatic clay waste and attapulgite slurries. This equation, [*V = a1 e ?k1/P + a2e ? k2/P] was found to describe the compaction of an attapulgite gel and a phosphate slime gel by a moving screen. [*V] is the ratio of the compaction achieved at a given pressure, P, to the compaction achieved at a pres-sure sufficient to remove all space between particles. The constant al represents the fraction of compaction achieved at low pressure by rearrangement of floes to higher packing density, and a2 represents the fraction of compaction achieved at higher pressure resulting from removal of voids within floes. K1 and K2 are constants determined from the experimental data. Both the low-pressure and high-pressure compaction mechanisms were observed in the compaction of the clays. These two compaction mechanisms offer an explanation for the observation that impounded slimes initially dewater rapidly and then dewater at a much slower rate.

Jan 1, 1982

By Bill M. Stewart, Philip W. Patton, Curtis C. Clark

Handling materials in underground mines continues to be a major safety problem. To help reduce materials-handling injuries, researchers at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health are investigating those materials-handling tasks in underground mines that appear to generate a high number of injuries. Data from the Mine Safety and Health Administration for the years 1989-1999 were studied to find out if there were any trends in materials-handling accidents and if so, to determine what tasks were involved and the sources of injuries. Several underground coal and metal mines we revisited to document innovative materials-handling technologies. Considerations for safety training and mechanization needs for continued reduction in materials-handling injuries are described.

By F. P. Miknis

Previous studies at the Bureau of Mines have shown that broad-line nuclear magnetic resonance (NMR) techniques have potential applications for rapid evaluation of oil-shale deposits. In a continuation of this study the techniques of pulsed NMR have been applied in a similar manner. The basis for the pulsed NMR oil-shale assay method lies in the assumption that the free induction decay (FID) amplitude following a 90° pulse is proportional to the potential oil yield. This assumption was tested on two groups of oil-shale samples, numbering 141 and 263 samples, from two different oil-shale cores. For both groups of samples a small number were selected as calibration samples. Free induction decay amplitude measurements were made on the 141 and 263 samples. The best least-squares regression line was obtained for the calibration samples, and the oil yields of the remaining samples were calculated using the slopes and intercepts obtained in the regression analyses. The agreement between measured and calculated oil yields was good, the indexes of determination being 0.93 and 0.89 for the groups of 141 and 263 samples, respectively.

Jan 1, 1974

By W. P. Yant

Publication of lists of the devices for giving respiratory protection which have been approved by the U. S. Bureau of Mines is made periodically for the purpose of aiding consumers in procuring equipment .374/ The last published list , approved to March 15 , 1935 , appeared as Information Circular 6845 with the same title as this article . The schedules of requirements and tests which the devices must meet in order to obtain approval are published 2/6/1/8/ by the Bureau of tests the devices must Mines and are available to the public . It is pertinent to mention that the preparation of a schedule of requirements for fresh-air supply devices of the types commonly known as positive -pressure respirators , airline respirators , sand- blast helmets , and hoods , has been practically completed and will soon be ready for release to the public .

Oct 1, 1936

By David C. Oyler

Methane-drainage holes must be completely filled by grout before mining to prevent the emission of large quantities of gas during mine-through, which would constitute an explosion hazard. In November 1980, seven horizontal holes at the multipurpose borehole, a small-diameter shaft drilled as a Bureau of Mines coalbed methane-drainage installation on the property of the Federal No. 2 Mine, Monongalia County, WV, were plugged using a sodium silicate gel grout. This report de- scribes the grout mix and the use of the grout at the multipurpose borehole, and discusses the results observed upon mine-through of the holes in early 1981. Cost data for the sodium silicate grout are also presented.

Jan 1, 1984

By Raymond M. Stateham

A portable, handheld infrared scanner has been used to detect abnormal surface temperature on dumps of flood-generated trash near Wilkes-Barre, Pa. Three of eight dumps examined had thermal anomalies on the surface, indicating temperature buildup at depth. The anomalies found with the scanner were verified by measurements with a thermocouple probe or a carbon monoxide detector. One week after the investigation was completed, open fire broke out at the site of one of these thermal anomalies; about 6 weeks after the investigation, a thermal anomaly in another dump was verified when a trench was excavated in the dump.

Jan 1, 1973

By H. M. Smith

In studying the chemistry of lubricating-oil fractions from so-called ?paraffin-base? crudes, one of the first requisites is a method for the separation and removal of waxy material. A method utilizing solvents for this purpose is described in this report, together with preliminary experiments with solvents that led to its development. The solvents actually used are secondary butyl alcohol, acetone, and mixtures of these.. Isopropyl alcohol was also studied. Preliminary Experiments In previous work on "intermediate-base" crude oil, following the work of Wyant and Marsh acetone had been used for laboratory separations of oil and wax. Then acetone was tried for the separation of the waxes and oils of "paraffin-base" crude, the volume of acetone required (80 parts to 1 part of oil) was found to be too great for large-scale work. For this reason the effectiveness of other solvents was studied; the separation by acetone, however, was used as a standard.

Jan 1, 1927

This chapter summarizes data on crude mineral production for the United States, its island possessions, and the Commonwealth of Puerto Rico. Included also are tables that show the principal mineral commodities exported from and imported into the United States, and that compare world and U.S. mineral production. Except for the mineral fuel commodities, the detailed data from which these tables were derived are contained in the individual commodity chapters of volume I and in the State chapters of volume II of this edition of the Minerals Yearbook. In October 1977, responsibility for the collection of data on mineral fuels-coal, petroleum, natural gas, and natural gas liquids-was transferred to the newly created Department of Energy. Although chapters covering these commodities will no longer appear in Volume I of the Minerals Yearbook, quantity and value data have been included in most of these summary tables to maintain statistical consistency in State and national value of overall crude mineral output. This shift in responsibility has also resulted in changes to the composition of the "Nonmetals? and "Mineral Fuels" groups in table 1 and table 2. The commodities-asphalt and related bitumens (natural), carbon dioxide (natural), helium, and peat-have been removed from the ?Mineral Fuels" group, and are now included under the "Nonmetals" group. There has been no change in the components of the "Metals" group.

Jan 1, 1981

By R. V. Ramani

This report, Volume I of the seven-volume Final Report on the U. S. Bureau of Mines research contract no. G0254030 titled Application of a Total System Surface Mine Simulator to Coal Stripping with the Pennsylvania State University provides an executive summary of the purpose and scope, objectives and results of the research. The remaining volumes of the Final Report, listed below, describe in detail model development, input and output documentation and the three case studies. Under the project, an existing surface mine simulator, Open-pit Materials Handling Simulator (OPMHS) was modified and extended for application to surf ace coal mining. In addition, two equipment selection models, and a cost model were also developed. Volume II: OPMHS User's Manual Volume III: Equipment Selection Models Volume IV: Surface Mining Cost Model Volume V: Application of OPMHS to an Illinois Mine Volume VI: Application of OPMHS to a South Eastern Ohio Mine. Volume VIII: Application of OPMHS to a South Western Mine.

Jan 1, 1978

By Robert K. Koch

Laboratory-scale studies on defluorination of natural and synthetic fluorspars by pyrohydrolysis at 1,500° C. were made to determine the feasibility of developing a process for producing hydrogen fluoride from siliceous fluorspars. It was found that the reaction (at 1,500° C.) is not promising for process development, even though a silica-free offgas can be generated. The primary difficulty is the low hydrogen fluoride content of the offgases; an HF content of 6 percent was the best achieved. Previous research by the Bureau of Mines has demonstrated that offgases averaging 27 percent hydrogen fluoride can be produced under carefully controlled conditions at 1,280° C. The lower temperature process is a better method for production of HF. However, charges in which the CaF to Si02 mole ratio varied from 0.4 to 2 could be processed with similar results. Also, combined alumina and ferric oxide contents up to 25 mole-percent did not noticeably alter the rate of defluorination. Therefore, virtually any natural siliceous fluorspar would respond in essentially the same manner when exposed to water vapor at 1,500° C.

Jan 1, 1962

By R. V. Mrazek

The heat of formation of vanadium trichloride was determined at 298.15° K. Measurements were made in a solution calorimeter in which an aqueous hydrochloric acid-potassium dichromate solvent was employed. Data are presented for the heats of solution of vanadium trichloride and the vanadium trioxide "backup" compound, and for appropriate dilution reactions needed to preserve stoichiometry. The resulting heat of formation of vanadium trichioride (VCI3) at 298.15° K was found to be ?H°298.15° K = -138.89 ±0.37 kcal/g mole.

Jan 1, 1968

By L. H. Adami

Heats of formation were obtained for four anhydrous crystalline sodium borates by hydrochloric acid solution calorimetry. The heats of formation at 298.15° K from the elements are NAB02, -233.2 ±0.6 kcal/mole; Na2B07, -786.4 ±1.0 kcal/mole; NaB305, -549.9 ±0.8 kcal/mole; and Na2B6013, -1,412.5 ±2.0 kcal/mole, The heats of formation from the constituent oxides are NaB02, -31.5 ±0.8 kcal/mole; Na2B407, -78.8 ±1.3 kcal/mole; NaB305, -44.1 ±0.8 kcal/mole; and Na2B8013, -96.7 ±1.5 kcal/mole.

Jan 1, 1968

By H. William Zeller

The Bureau of Mines performed laboratory research to determine the effects of a barium-based fuel additive on diesel particulate emissions. The test engine was typical of types used to power underground coal min-ing equipment. Test parameters consisted of baseline measurements without additive, three fuel additive concentrations, and five steady-state engine loads, all at 1,200 r/min. Additive effects on soot mass concen-tration, opacity, particle size distribution, volatile fraction, and NOx emissions were determined. Important findings are as follows: Using the manufacturer's recom-mended additive concentration increased the gravimetrically measured mass of particulate by 30 to 80 pct at four of the five steady-state load conditions. Soot measurements by optical methods did not agree with those by gravimetric techniques, for additive-treated fuels. The additive reduced volatile hydrocarbons adsorbed on filter deposits by up to 50 pet. At most engine loads, carbon particulate was also reduced. About 40 pet of the barium added to the fuel was accounted for in the exhaust. The health implications for miners were considered, but no firm conclusions were drawn or recommendations made because the results are for steady-state conditions, which may not be representative of real-world operation of diesel-powered equipment underground.

Jan 1, 1987