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By W. R. Gilliland, G. W. Jones

"One-phase of the accident prevention program of the Bureau of Mines is the determination of the explosion hazards of various combustible gases and vapors encountered,mining and allied industries and the development of means and methods of eliminating them.Gasoline is foremost among the combustible-liquid's as to quantity used and variety of applications in industry, It is a chief contributor to the causes of fires and explosions, taking an enormous yearly toll in property damage and considerable loss of lives.The results presented in this report evaluate the effect of various gaseous inert substances, which owing to their chemical composition, should be of considerable value in the prevention of gasoline fires and explosions. The substances investigated are as follows: Nitrogen (N2), automobile exhaust gas (85 percent N2 + 15 percent CO2), carbon dioxide(CO2), dichlorodifluoromethane (CCl2F2-Freon-12), trichloremenofluoromethane (CC13F-Freon-11), and dichloromonofluoromethane (CHCl2F-Freon-21).The general term ""gasoline"" designates a combustible liquid of such characteristics as to give satisfactory operation without preheating in spark-ignition-type internal-combustion engine. It comprises a complex hydrocarbon mixture having a limiting distillation range and produced commercially by distilling or ""cracking"" crude petroleum or other various petroleum stocks. Small proportions of other substances may be incorporated in the gasoline to enhance its antiknock properties or operating characteristics in internal-combustion engines and to increase its stability during storage, transportation, and use.It is thus seen that gasoline may have rather wide variations of chemical and physical properties, and it would: appear that the results of any investigation dealing with one particular gasoline might not be applicable to other types. However, as indicated by the results given in this report, the inflammable properties of different gasolines at normal atmospheric temperatures are influenced largely the mars volatile hydrocarbons containing 5, 6, 7 carbon atoms- in the molecule, and that the heavier constituent of higher molecular weight have a minor influence on the inflammable properties at ordinary temperatures."

Apr 1, 1946

By Manuel Gomez

A computerized moving average technique was developed to interpolate coal seam characteristics between sample points. The interpolative method coupled with multivariate regression analysis and simulation procedures was used to forecast coal properties not readily obtained from an analysis of drill core samples. Coal property forecasts were of two kinds: (1) specific mine property forecasts that are suitable for mine product control and yield a good approximation of the local variation along both the vertical and horizontal axes of the seam, and (2) regional estimates where much of the local seam variation is smoothed out, but the general trends are maintained. Forecasts of the volatile matter, ash, total sulfur, and the heating value for part of the Pittsburgh seam located in Ohio, Pennsylvania, and West Virginia were in good agreement with independent evaluation data. Spatial configuration for preparation characteristics, particularly, the effect of crushing on sulfur release, low-and high-temperature carbonization properties, the Hardgrove grindability index, the coal hardness index, gasification variables, and hydrogenation factors were constructed for the same area of the Pittsburgh seam. These forecasts may be developed from drill core data collected in the exploration phase of mining. The results, which may take the form of a series of maps, are useful to mining, chemical, and combustion engineers, to economists and mine managers, as well as to coal users for mine design, economic analyses, energy forecasts, utilization studies, mine product control, and environmental control and programming.

Jan 1, 1974

By Foster Fraas

This report describes the application of pulsed magnetic fields derived from alternating and intermittent magnetizing currents. Application of such pulsed magnetic fields to the matrix-type separator permits (1) the complete discharge of the magnetic fraction with wet feeds and (2) the dry separation at particle sizes down to 325 mesh. At smaller particle s indications are that frequencies above 60 hertz will be required. Applications of intermittent magnetizing current to the cross-belt separator give the cross-belt-separator an advantage over the conventional constant-field cross-belt and induced roll separators; the intermittent current enables the cross-belt separator to separate matted fibrous and magnetically coagulating feeds, a type of feed that occasionally occurs with mineral, industrial, and secondary materials.

Jan 1, 1973

By John K. Alley

Fibrous silicon carbide was produced by thermal decomposition of certain silicates contained in graphite crucibles. Induction heating was used to produce the necessary temperature and thermal gradients. Both green and white fibers were mainly the beta modification even though each color grew within a different temperature zone. Alpha silicon carbide, present in insufficient amounts for X-ray detection, was identified by electron diffraction. The white fibers formed in a zone between 1,365° and 1,634° C (±50° C). The green fibers (less contaminated) formed in a much more narrow zone between 1,650° and 1,672° C (±50° C). The average lengths and widths of microscopic fibers grown by this method were 1.5 mm/0.002 mm (white) and 1.2 mm/0.0035 mm (green); however, same fibers observed by electron microscope had cross-sectional measurements of 150 to 300 A. Both differential thermal analysis and thermogravimetric analysis showed that silicon carbide fibers oxidized in air at temperatures above 500° C. Fibrous silicon carbide was indexed as a cubic cell with the dimensions a = 4.358 A. The density calculated from X-ray data was 3.217 g/cm3.

Jan 1, 1963

By James Westfield

Uranium activity has introduced a comparatively new hazard to United States mining. In addition to the hazards common to all mines, uranium mines have a complex health problem of radiation damage. Like many new processes, radiation and nuclear energy can be made to serve man in many useful ways when properly understood and handled; but, like fire, gases, and electricity, their potential dangers must be known and respected, and appropriate precautions must be taken or death may result. Since 1950 the Public Health Service has been conducting basic investigations on exposure to radon and its daughter products and the effect of exposure upon the health of miners in uranium mines of the Western States. The Bureau of Mines assisted in several of these investigations, especially in mines on Indian lands. The studies have shown that a serious health hazard exists from radioactive exposure that might cause lung cancer if continued over a number of years. The Public Health Service report, Control of Radon and Daughters in Uranium Mines and Calculations on Biologic Effects,6/ shows that 55 percent of the uranium mines employing 64 percent of the miners had atmospheric concentrations more than five times the working level now accepted as reasonably safe for industrial exposures. Extensive control measures are necessary to reduce these concentrations to the suggested working level of less than 300 micromicrocuries of total radon daughter products per liter of air.

Jan 1, 1958

By A. L. Engel

This report is a compilation of results of preliminary concentration tests of nine manganese-ore samples in 1953-1954. Three samples were from Nevada and the other six from California. These samples represent marginal or low-grade ores from deposits that have been mined selectively in the past. The present interest lies chiefly in the possibilities of concentration of the remaining low-grade ores for economical exploitation. The treatment methods included gravity concentration and flotation in most cases. Results were sometimes unsatisfactory, particularly when the ore was too fine grained for liberation of the minerals within economical grinding range. The contaminating gangue minerals, such as quartz and iron oxides, were locked with the manganese to an extent that prevented separation of high-grade concentrates with satisfactory recovery. In cases where fairly good concentrates were made, it was at the expense of recovery, a condition typical of low-grade ores.

Jan 1, 1955

By John E. Hamak

The identified helium resources of the United States were estimated by the U.S. Bureau of Mines at 617 Bcf, as of December 31, 1992. This includes 285 Bef of demonstrated reserves, 85 Bcf of demonstrated marginal reserves, and 37 Bcf of demonstrated sub-economic resources. The identified resources also include 166 Bcf of helium in inferred reserves and inferred marginal reserves and 44 Bcf in inferred sub-economic resources. The identified helium resources contained on Federal lands are approximately 172 Bcf, including 32 Bcf in underground storage in the Cliffside Gasfield near Amarillo, TX. Undiscovered helium resources in the United States are estimated at a most likely volume of 104 Bef, with a maximum volume of 249 Bcf and a minimum volume of 41 Bef. Also reported are 51 Bcf of helium in nonconventional and low-helium-content natural gases. Extraction of helium in the United States occurs mostly from natural gases produced from the Hugoton gas area in Kansas, Oklahoma, and Texas, and the Riley Ridge area in southwest Wyoming. Helium extracted from natural gas in the United States in 1992 was 3.3 Bcf. Some shortfalls in helium supply may occur in about 5 to 10 years.

Jan 1, 1995

By N. S. Dalal, X. Shi, V. Vallyathan

"Electron spin resonance (ESR) and cytotoxicity measurements were made on newly fractured silica to examine specifically the role of the fractured-induced, siliconbased radicals (Si· and SiO·), and silica-generated hydroxyl (·OH) radicals in the mechanism of the cell membrane damage by silica. The concentration of the Si· and SiO· radicals was controlled through decay processes, thermal annealing, and boiling, while that of the ·OH radicals was varied by using catalase, superoxide dismutase, KMnO4, Ha2seO3, ascorbic acid, and metal ions, and monitored via ESR spectroscopy. The dust's cytotozicity potential was evaluated by measuring the silica-induced hemolysis and also by determining lipid peroxidation (using linoleic acid). Prom the comparison of hemolysis and ESR results it is deduced that the radicals play little· or no role in the silica-induced hemolysis. However, the lipid peroxidation data indicate that the radicals might be involved in the initiation of an oxidative chain reaction leading to the macrophage membrane damage through lipid peroxidation. INTRODUCTIONThe biochemical mechanism of Quartz-related pneumoconiosis is still not fully understood. It is believed, nevertheless, that one event of primary importance is the perturbation of cell membranes by the dust particles (Allison et al., 1966; Allison and Harrow, 1971; Bateman et al., 1982; Parazzi, et al., 1968; Reiser and Last, 1979; Shi et al., 1989; Summerton et al., 1977). The ensuing cell-membrane damage unleashes certain lytic enzymes resulting in additional cell injury and eventual fibrosis (Nolan et al., 1981; Summerton et al., 1977). Thus considerable effort is currently being made towards the understanding of the processes by which quartz particles disrupt the membrane of a red blood cell (RBC) or a pulmonary alveolar macrophage (PAM). A simple but important method of evaluating the membrane damage potential of a dust is the hemolysis test (Harington et al., 1971). Even though this test is used routinely for screening dusts for their cytotoxicity potential, the biochemical mechanism underlying the cell lysis by many dusts, including quartz, is still controversial (Kilroe-Smith, 1974; Singh and Rahman, 1987), and this provided us the impetus for the present undertaking."

Jan 1, 1989

By R. W. Van Dolah

An attempt has been made in this investigation to define the conditions under which ammonium nitrate (AN) might detonate as a result of involvement in fire. The initiation of detonation by shocks derived from explosives or from projectile impact was investigated as a function of temperature and charge diameter. A new technique was devised to investigate the burning of raw and contaminated AN under pressure. No transition, to detonation in AN was obtained in the burning experiments. The critical diameter for detonation of fertilizer-grade AN was found to be quite small when the AN was at temperatures just below melting point; this indicates that initiation of detonation may be less difficult at elevated temperatures but such initiation by gas-phase detonation was shown to be unlikely. Transition from burning to detonation was obtained with AN intimately mixed with fuels that included polyethyl-ene, paper, and fuel oil when these were contained in vessels with restricted vents. However, the experimental results supported by an analytical study indicate that the initiation of detonation in AN from fire exposure in normal storage and from transportation incidents is quite improbable. The detonation of AN in recent incidents more likely may have resulted from the effects of adjacent explosions.

Jan 1, 1966

By L. F. Willmott

The production operation of a Kerpely gas producer at Louisiana, Mo., is described. This unit, originally designed for airblown operation was modified to permit using oxygen in the blast in place of air. The first runs J for test purposes, were made in June 1950. After this, seven production runs were made and these are the subject of this report. Total gasification time was 245 days. In each run, Nut or Pea coke or mixtures of both at a rate varying from 1,700 to 2,300 pounds per hour was converted with oxygen and saturated steam to produce synthesis gas - primarily carbon monoxide and hydrogen -approximating a predetermined rate of 80,000 to 95,000 cu. ft. per hour and a predetermined hydrogen-carbon monoxide ratio, The requirements per 1,000 std. cu. ft. of (CO + H2) were 21.6 to 30 pounds of coke, 213 to 267 std. cu. ft. of oxygen, and 3L4 to 47.B pounds of steam.

Jan 1, 1955

By John T. Dieckmann

This report documents the work performed and the results obtained in a 2-year development of a Mobile Inert Gas Generator for use in the Bureau of Mines Remote Sealing System for fighting underground coal mine fires. The performance requirements of an inert gas generating system for the Remote Sealing System were clearly established. A thorough review of seven possible system designs meeting these requirements was conducted. An air cooled, distillate oil fired combustion type inert gas generator was selected for further detailed design, hardware fabrication, and performance testing. The Inert Gas Generator constructed under this program has been thoroughly performance tested and has been operated in the field for approximately 200 hours. The system has met or exceeded all important performance requirements. The system was used in the fire fighting efforts at the Bethlehem Mines Corporation Cambria Division Mine 33 fire and contributed to the successful containment of the fire. The system was also employed in the demonstration of entire Remote Mine Sealing System at the Jenney Mine in the fall of 1978. The system is currently avail-able for fighting any future underground coal mine fires.

Jan 1, 1979

By D. A. Elkins

This report is the second of a series of three that will evaluate, in order, the metallothermic, carbothermic, and electrolytic methods of magnesium production. The historical development of the carbothermic process is outlined. Production costs varying from 38.9 to 21.8 cents per pound of magnesium are estimated for different versions of the process. Additional suggested process modifications are listed. The technical and economic potential of the different versions are compared. Areas deemed most promising for future research on the process are delineated.

Jan 1, 1967

PURPOSE: Evaluate practical technological advances in level-dependent hearing protectors and inexpensive personal acoustic monitors. RESEARCH SUMMARY: The results of previous NIOSH research show that miners develop hearing loss much more quickly than nonoccupationally noise-exposed individuals and that miners experience a greater severity of hearing loss than would be expected for nonoccupational noise-exposed persons of the same age and gender. Using hearing thresholds at 4,000 Hz as an indicator, coal miners experience hearing loss 2.5 to 3 times greater than would be expected for persons not exposed to occupational noise. At age 50, 90% of coal miners and 49% of metal/nonmetal miners were found to have a hearing impairment. In comparison, only 9% of a nonoccupationally exposed control group had a hearing impairment at age 50.

Jan 1, 2000

By C. D. Litton

This Bureau of Mines report presents a set of guidelines for determining the distribution of product-of-combustion fire sensors in underground mines. Sensor spacing is defined in terms of sensor alarm threshold, ventilation flow rate, and mine entry dimensions. Sensor spacing guidelines are presented for detection of fires from two primary combustibles, coal and wood, which are common to the majority of underground mines. The guidelines are based on data from full-scale and intermediate-scale fire tests conducted by the Bureau of Mines.

Jan 1, 1983

By P. M. Sullivan

Galvanizers' sal skimmings have been treated by two methods of leaching in attempts to produce preflux solutions suitable for use in galvanizing operations. Both water-leaching and acid-leaching procedures are effective, except in severely exhausted skimmings when water-leaching becomes impractical. A preliminary analysis of the skimmings is not required. Solutions in the recommended concentration range can be produced conveniently by control of pH, specific gravity, and chlorine content. A technician would require only a short period of training to be able to perform the operations described.

Jan 1, 1958

By R. M. Santmyers

Except for optical purposes and a few other special uses quartz and quartzite are to a considerable degree interchangeable. This also may be said with respect to pulverized quartz and ground silica sand, which are discussed in a separate paper of this series. All these materials, except perhaps quartz crystals of optical grade, are abundantly available in many parts of the United States. In the form of ordinary crushed stone much of it is sold at $1 a ton or less, and ordinarily

Aug 1, 1931

By R. S. Dean

The development of metallurgical processes may be divided into periods : First , the discovery of a basic reaction which brings about the production of the desired product from the available raw material ; second , a long stage of mechanical development during which little or no attention is paid to the reaction itself ; and third , a careful study of the reaction . Most metallurgical processes are to -day approaching the end of the second period . This we may illustrate by the steel process . The reaction of carbon with iron ore to produce pig iron and the subsequent refinement of the pig iron by an oxidation reaction is very old . Development in modern times has been almost entirely mechanical , the development of the blast furnace , furnace , the Bessemer process , the Siemens process , and even the Aston process for wrought iron being mechanical improvements almost entirely . Metallurgy is now entering a phase where the reactions are being considered . The question of how far can they be made to proceed is being repeatedly asked . As mechanical processes are improved , we approach a limit to which our basic reactions can be pushed which is determined by the nature of the reactions themselves . We want to know : How far can iron be decarbonized by iron oxide ? How low can the oxygen of copper be reduced by any given reaction? How efficiently can the fuel in a zinc reduction process be used ? The demand for purer metals and lower production costs has forced these and similar questions upon us . How are we to answer them ? The determination of these equilibria or end points of metallurgical reactions by direct means is fraught with difficulty because here we must overcome mechanical difficulties which too often become the limiting factors even in the laboratory and we do nottherefore get the actual limit to which the reaction itself may be carried . Further , there are so many reactions of metallurgical materials that to survey each separately is a job to give pause to any experimenter or group of experimenters .

Dec 1, 1930

By M. J. Kovalik, D. E. Wolfson, F. Fischler

Plastometric tests were made to determine the maximum thickness of the plastic layer for different U.S. coals . The effect of test variables on the maximum thickness of the plastic layer was studied . The values for the maximum thickness of the plastic layer were found to be related to the Gieseler maximum fluidity , plastic temperature range , free swelling index , and other plastic properties of coals . Only a general relationship was observed between the plastometric parameters obtained in these tests and the coking properties of coal .

Jan 1, 1964

By R. Hogg, S. Chander

"An overview of various physical and interfacial characterization methods for use in mineral processing is presented in this paper. The availability of a large number of characterization techniques and commercial instruments requires that the reliability and limitation of each be carefully examined. The choice of a method may depend upon the manner in which the information is to be used, for example in development of new processes, plant and process design, plant control, problem solving, etc. IntroductionThe behavior of particulate systems, in mineral processing and other applications, is primarily affected by the physical characteristics (size, shape, surface area, pore structure) of the particles and the nature of the different solid-fluid interfaces present. Mineral processing operations in general are either designed to modify and/or control physical and interfacial properties (grinding, classification, agglomeration, etc.) or are strongly influenced by them (flotation, flocculation, solid/liquid separation, etc.). Characterization of physical and interfacial properties should be an integral part of the development of new processes, plant and process design, and routine plant operation.Our purpose in preparing this article has been to present an overview of the current status of characterization, to point out areas of weakness, and to discuss the reliability and limitations of the various techniques, procedures, and instrumentation available. For more detailed discussion of methods, etc., the reader is referred to standard references.Sampling particulate solids.Sampling is a critical factor in any procedure for characterizing particulate materials — the reliability of characterization data is ultimately limited by the extent to which the sample used was truly represen¬tative of the population from which it was taken.Sampling from particulate solids involves two basic problems: (1) the selection of a random', unbiased sample and (2) choice of the appropriate sample size.The problem of sample selection involves the design of a sample collection procedure that ensures that every kind of particle in the population has the proper chance of being included in the sample without bias. Specific procedures such as the well-known cone-and-quarter technique have been developed and are discussed at length in the literature on particle characterization (Allen, 1981: Herdan, 1960: Gy, 1982)."

Jan 1, 1989

By C. Q. Cupps, R. F. Zaffarano, J. Fry

Reservoir oil analyses from seven wells in the Greater Clareton area have been included in a study of the original characteristics of oil in the Newcastle sandstone reservoir . These data correlated with areal location of the wells show an increase of saturation pressure in a general north - south or downdip direction . The increase amounts to about 500 psi in more than 17 miles , which corresponds to a depth increase of about 1,600 feet . To facilitate application of the data to engineering analyses , average characteristics are given for arbitrary north and south divisions of the 22 - mile - long producing area . The downdip increase of saturation pressure is taken as evidence of updip diffusion of solution gas from a somewhat higher concentration at the bottom of the reservoir . This effect is opposite to that previously observed in two prominent high- relief reservoirs in the Rocky Mountain area . The increasingly greater saturation pressures southward or downdip in the Greater Clareton area suggest a continuing migration of fluids into the structure .

Jan 1, 1964