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By E. K. Kleespies

The rate of the heterogeneous reaction between titanium-oxygen solid solutions and titanium trichloride in molten sodium chloride was determined at high temperatures. In the alpha phase, the reaction rate decreases uniformly with the increasing concentration of oxygen. The gamma crystalline form of titanium (above 33 atomic percent oxygen) was much less reactive than the alpha phase, and the reaction rate approached zero at 50 atomic percent oxygen. The activation energy for the reaction of titanium-oxygen solution containing 22.8 percent oxygen was 11.7 kcal/mole of TiCl3 as compared with 8.3 kcal/mole of TiCl3 for pure titanium.

Jan 1, 1967

By Steven J. Schatzel

Gas drainage through surface bore-holes has been the conventional means of methane control for U.S. longwall gobs. However, these vertical boreholes are becoming so costly, and the surface rights so difficult to obtain, that the Bureau of Mines is developing underground gob gas drainage as an alternate means of methane control for U.S. longwalls. Holes are drilled into the roof over the panel and on retreating longwalls, towards the working face from a location inby the face. As the longwall retreats, an increasing portion of the hole intercepts the fracture system over the caved gob. A surface exhauster maintains a vacuum on a pipeline parelleling the panel and draws the methane mixture out of the mine. Auxiliary systems of gob gas drain-age during longwall mining will be essential for an increasing number of coal mines. Deep and gassy mines often find ventilation insufficient for adequate dilution of methane in bleeder entries. Although this cross-measure method of degasification has been used successfully in Europe, some of the European techniques cannot be directly applied to U.S. mines. This is the first study of its kind in this country.

Jan 1, 1982

Coaxial cable structures form the subject of substantial theoretical and experimental investigations either directly related, or which can be extrapolated, to the communications needs and environments of U.S. coal mines. Communication systems based on "guided" waves, of which "leaky" coaxial cables are one implementation, are attractive candidates for providing a range of communication functions primarily along haulage ways, and possible also within sections up to the working face. (However, there are still strong reservations as to whether a practical coaxial cable sys tem could provide sufficient communications coverage within a section. ) In this Part, we present the results of some theoretical calculations of the performance of leaky coaxial cable communication systems. We also analyze the applicability of the theoretical and experimental results obtained by other researchers to the needs of U.S. coal mines. In particular, this investigation has been focused on the utility of relatively low cost, conventional, flexible, coaxial cable at frequencies covering the LF through HF bands and extending into the lower part of the VHF band, as opposed to relatively high cost, special semi-rigid, coaxial cable* at frequencies in the VHF and UHF bands. There are three major design alternatives for coaxial cable communication systems considered in this chapter: • Base station feeding a coaxial cable with high surface transfer impedance (holes in outer conductor, e.g., braid construction). • Base station feeding a coaxial cable with repeaters (U.K. experiments). • No base station, direct communication via a coaxial cable with periodic radiative structures.

Jan 1, 1974

By Harry G. Dosh

Sillimanite, kyanite, and andalusite are aluminum silicates having the same chemical composition (Al2SiO5) and are used in the ceramics industry for the manufacture of high-grade refractories. Natural sillimanite with added corundum or other alumina to just short of mullite (3Al2O3 -2SiO2) proportions is unequalled for jobs wherein strength at high temperatures, resistance to spalling, and resistance to slagging by acid slags are desired. High-grade porcelain ware also requires these minerals. At the same cost, sillimanite would be preferred for most uses, but the lack of any large source of sillimanite bas given economic preference to kyanite or andalusite for special refractories and high-grade porcelain wares. Sillimanite-bearing schists were observed in Spartanburg County, S. C.; as early as 1937 by D. Hoye Eargle, geologist with the U. S. Soil Conservation Service. The mineral was not identified until 1942, when Miss Jewell Glass, of the U. S. Geological Survey, examined several of the deposits. This identification was confirmed in 1943 by Dr. Laurence L. Smith, of the University of South Carolina, when he examined the Spartanburg County deposits and found numerous additional occurrences of sillimanite schist in Greenville County. Subsequent work by the Bureau of Mines and the South Carolina Geological Survey has been responsible for the location of additional sillimanite-rich schist deposits in Spartanburg County. Between October 1, 1948, and November 21, 1948, the Bureau of Mines conducted an exploratory diamond-drilling project on the John Gideon property in the southeastern section of Spartanburg County (fig. 1) and drilled a total of 681.7 feet in six holes. Drilling indicated that the deposit is relatively shallow, as no ore was cut below the zone of weathering.

Jan 1, 1950

By David Hoadley, Kenneth R. Maser, Ashok B. Boghani, James E. Billar, D. Randolph Berry, Mackenzie Burnett, Robert H. Trent

2, Survey of Representative Group of Metal and Non-mental Mines Before proceeding to develop and analyze Emergency Escape System Guidelines, it was necessary to obtain a broad range of information, including both fact and opinion. Although there were many areas to consider, the surveys had three primary goals 1. To determine the current state of underground escapeway planning and execution in American, metal and non-metal mines. 2. To determine, for a wide range of mining conditions, what difficulties can be encountered in complying with present and proposed escapeway regulatory standards. 3. To determine what improvements could be made and what equipment and technology was available to aid in implementing these improvements. To accomplish these goals, three major surveys were undertaken¬ 1. Survey of MESA and State Mining officials, discussed in Section 2. 1. 2. Survey of representative U S metal and non-metal mines, discussed in Section 2. 2. 3. Survey of manufacturers supplying equipment, primarily hoisting, suitable for use in escape systems, the product information which was obtained is discussed in Section 7.

Jan 1, 1976

By J. G. Schoning

The Holmes Safety Association is an offspring of the Joseph A. Holmes Safety Association which was organized in Washington, D. C., in 1916 at a meeting of representatives of twenty-four leading mining associations connected with every branch of the United States mineral industries. The purpose of the meeting was to do honor to the memory of Joseph A. Holmes, one of the founders of the United States Bureau of Mines and its first director, whose death had occurred the year before on July 12, 1915. In deference to what was believed would have been the expressed wish of this great humanitarian and benefactor of the mineral industries, it was decided to establish a national safety organization to cover the mineral indus¬tries exclusively; out of respect for his memory and service, the organization was named the Joseph A. Holmes Safety Association. On receiving requests from several mining districts, in 1922 a number of chapters ware established in several mining States.

Jan 1, 1929

By J. E. Tiffany

"The new permissible blasting device, Cardox, utilizes as a blasting agent liquid carbon dioxide which is discharged.as a gas from a steel container or shell. The loaded shell is placed in a borehole, stemmed, and tamped in a manner similar to that employed with explosives, and is fired by electricity.The Bureau of Mines' approval for use of the device in coal mines was granted as Approval No. 1 under date of October 3, 1928; as the result of tests made under the conditions and requirements of Schedule 20. There have been three subsequent extensions whereby minor modifications in the original design were granted.The permissibility of the device is subject to the following conditions; (1) It shall be in all respects similar to the sample submitted for tests; (2) certain thicknesses of disc and. weights of heater ingredient and of carbon dioxide, all of which are set forth in Table 2 under the provisions governing permissibility, must be used: (3) the rear cap must always be in place after the shell has been charged, to prevent accidental firing; and (4) firing must be done by means of a permissible-type blasting unit.The permissibility of Cardox was established by gallery tests similar to those used in testing explosives for permissibility. In these tests the shell was discharged into gallery 1 without causing any ignition of gas and air or of gas, dust, and air mixtures there. The conditions of charging the shell, such as weight of the ingredients of the heater element, the carbon dioxide charge, and thicknesses of the disc, were varied according to the conditions under which it would be likely to be used in blasting. The tests made in gallery 1 are here described in detail, as are also the tests which have been made for determining the propulsive strength of the device and the quantities of poisonous gases given off when a shell is discharged."

Mar 1, 1929

By Richard A. Thomas, Michael J. Sapko, Gary L. Mowrey, William D. Monaghan, Michael A. Trevits

Over the years, more than 20,000 mine seals have been erected in underground coal mines in the United States. Seals are used extensively in underground mines to isolate worked-out areas, active mine fire zones, and to control water inundations. Seals are most often built directly in the mine and can be fabricated from blocks made of wood or cementitious material. Recently, several explosions occurred within sealed areas of underground U.S. coal mines. These explosions, believed to be initiated by lightning strikes on the surface, destroyed numerous seals and caused considerable damage external to the sealed area. The National Institute for Occupational Safety and Health is conducting research to develop design guidelines, to investigate noninvasive techniques to characterize seal strength properties, and to evaluate seal test methods. As part of this work, a 30-ft wide, 16.1-ft tall and 4-ft thick seal was built in an underground experimental mine using cement and foamed water. Two types of noninvasive techniques are currently being investigated, namely the Schmidt Hammer for measuring compressive strength and ground penetrating radar (GPR) for detecting the presence of anomalies (e.g., voids, discontinuities) within the seal. Once these noninvasive tests were completed, the seal was subjected to destructive explosion testing. This study presents the results of the Schmidt Hammer tests, GPR scans, and the characteristics of seal failure during explosion testing.

By David C. Byrne

From an engineering perspective an ideal industrial noise control solution focuses directly on the actual source of the poise. Eliminating the noise-generating mechanism altogether obviates the need for other noise contra l treatments or hearing protection devices. However, in cases where attenuating the source is not feasible engineering controls must be oriented toward blocking the path that the sound waves travel toward employees. Acoustical enclosures are commonly used as sound path treatments to contain the noise from a machine: alternatively a control room/booth or equipment operator's cab may be used to isolate the worker from the noise. Anyone who has successfully used acoustical enclosures knows that the design procurement, and installation process is deceptively simple. Alt too often First-time efforts fait to account for many of the constraints that can render the enclosure essentially useless. Things that cannot be overlooked include: providing convenient worker access (physical and visual): allowing for proper machine operation/product flow; and supplying fresh air or preventing undue heat or contaminate build-up inside the enclosure. All of these factors must be given careful consideration, otherwise the enclosure will not perform adequately.

By R. L. Crosby

The Bureau of Mines investigated alloys of copper with 2, 3, and 4 vol pct alumina and with 2 vol pct yttria. Alloys were prepared by a coprecipitation process and were fabricated by pressing and sintering of powders, extrusion, and swaging. Tensile properties at room and elevated temperatures, stress-rupture strength, electrical conductivity, and density were measured. The superiority in elevated temperature strength of dispersion-strengthened copper to OFHC copper was confirmed. Increasing the oxide content from 2 to 4 vol pct produced only a small improvement in strength properties and decreased the electrical conductivity. The 3 vol pet alumina alloy had the best overall combination of properties.

Jan 1, 1969

By R. T. Artz, Simpson. O. V.

"INTRODUCTION The provision of escapeways from coal mines is a moral and, in most States, a legal obligation of mine owners and operators. The obligation is not always fulfilled because of the hope that no occasion will ever arise requiring the use of such facilities, and, as time passes without the need for using them, a false sense of security is born in the belief that ""it can't happen here.""The disastrous fire in a mine in Ohio on July 5, 1944, again focused attention on the importance of escapeways in averting disasters and made it clear that one or more dependable exits must be provided from a mine and parts thereof where men might be trapped by being cut off from the regular travel route. This matter of always-having available travelable exits has been advocated for many years by the United States Bureau of Mines."

Aug 1, 1948

By N. C. Tomoeda, W. D. Bensema, J. W. Adams

Measurements of surface magnetic field noise were made at various locations over the Geneva Coal Mine near Price, Utah, on June 12, 1973. The locations selected were on the surface over emergency locator beacons underground at depths between 350 meters (1150 ft .) and 488 meters (1600 ft .) . The surface terrain where these measurements were made was mountainous, and access was difficult. There were no power lines within several miles, and the weather was clear; therefore, the magnetic noise levels were about as low as will normally occur. Results of measurements of distant sferics indicate rather sharp cutoff frequencies below which broad- band, impulsive noise is attenuated. The mechanism of propagation for this noise above the daytime cutoff frequency of 3500 Hz and the nighttime cutoff frequency of 1700 Hz is deduced to be a waveguide formed by the D or E layers of ionosphere as an upper plane and the earth as a lower plane. The measurement systems used are similar to those used earlier. The technique is to record broadband, analog signals, digitize the data, and use a fast- Fourier transform to obtain spectral plots. This tech- nique is novel in that it can measure simultaneously all magnetic field energy within a limited portion of the spectrum for a limited time, and, after processing, reproduce the events occurring in that time interval in great detail .

Jan 6, 1974

By James E. Hill

In the course of exploratory drilling during World War II by the Bureau of Mines under the Strategic and Critical Minerals investigations Program, a problem arose as to the ultimate disposal of the drill core resulting from that program. The difficulties experienced in obtaining factual information to evaluate mineral deposits examined (during that program) influenced the Bureau in a decision to catalog and store the drill cores for future reference. Initially, the drill cores were stored at the nearest Bureau of Mines station that had space available for the purpose. Recently the Bureau stations at Minneapolis, Minn., and Denver, Colo., were designated as the locations of permanent drill-core storage facilities. Drill cores that are retained from Bureau of Mines mineral-exploration projects are stored at these two locations and are given preference in selecting cores for storage. Drill cores are accepted also for storage from other Government agencies, State agencies, private companies, or individuals on the basis of available facilities and consistent with the significance of the core in relation to Bureau of Mines objectives and national interest. Selection and acceptance of such drill core are determined by the Bureau of Mines. The drill cores stored at the two locations are available for inspection by any person having a legitimate interest in the mineral deposits represented by the cores. Approximately 1,850,000 feet of drill core can be stared in the facilities now available to the Bureau of Mines. Approximately 475,000 feet of drill care is stored or scheduled for storage at Minneapolis, Minn., and 240,000 feet of core stored or scheduled for storage at Denver, Colo. A list of drill core now in storage at the Bureau of Mines core-storage facilities at Denver and Minneapolis is included as appendix A.

Jan 1, 1957

By H. E. Dresch

This report summarizes the work accomplished under Bureau of Mines contract H0188068. The contract required design and construction of a high voltage (7.5 KV) explosion proof cable connector for use on underground coal mine drag cables. A connector was constructed with elastomeric phase insulators that provide insulation shielding throughout the connector length. Connector housing was made of flame resist-ant cast poly urethane with no exposed metal components. Electrical and mechanical testing of the completed coupler resulted in satisfactorily meeting most of the design testing requirements.

Jan 1, 1981

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 W. T. Abel

The Bureau of Mines tested 48 materials for their ability to absorb H2S from hot simulated producer gas (1,000°-1,500° F). The material found best from the standpoint of absorption capacity, durability, and amenability to regeneration was sintered pellets of 75 percent fly ash-25 percent Fe203. The performance of this absorbent under simulated and actual conditions is described. The effect of absorbent composition, absorbent temperature, steam content of the gas, and tar vapors and dust in producer gas is discussed.

Jan 1, 1974

By C. Lorimer Colburn, Spencer P. Howell

"Numerous accidents are still being reported that have resulted from the delayed explosions in drill holes. Some of these accidents have boon due to retarded burning of the fuse, causing the charge to explode after the miners had returned to the face, but the majority have been caused by the minors drilling or picking into unexploded explosives, either in unexploded bolas or in broken rock. Although the industry has been cautioned by the Bureau of Mines, manufacturers of explosives, and other agencies regarding the care that is necessary in the handling of explosives, yet reports of these accidents are still being received and many of the accidents are fatal, They occur in spite of the best efforts of the mine officials and men, but many of those that have been reported could have been avoided if the following precautions had been observed:Misfires should not be approached even for the purpose of inspection until three hours have elapsed if fuse was used, and ten minutes if electric detonators or electric igniters were used. These are minimum recommendations. It would be preferable to allow a longer time, for fuses have been known to hang fire for twelve hours."

Aug 1, 1920

By Roy S. Nutter

An expert system advisor consultant to assist a coal mine section foreman is described in this report. The system is designed for an underground continuous miner section that is being specifically used for longwall development. The system provides three methods of operation that include normal operational mode for use underground, a training mode for use in training section foremen under controlled classroom conditions, and a demonstration mode that is free running. The Face Decision Support System or FDSS, is designed to interface with section environmental monitoring equipment and section production monitoring equipment that may appear in the future. This provides automated reprioritzation of the section foreman's job list from the system. The system 1S written in LASER which is written in C and is operated under the UNIX operating system. The objective of the entire FOSS system is to ensure that no job or piece of information important to safety or to production is forgotten because of the immediate problems confronting the section foreman.

Jan 1, 1988

By R. Craig Smith

The Bureau of Mines conducted a study of production costs for the secondary lead industry and determined costs for present, pending, and proposed environmental legislation. Operating costs for smelters by capacity groups range from 16.8 to 19.6 ¢!lb of refined lead. Present regulatory compliance costs for these groups range from 2.2 to 2.4 ¢!lb. Pending compliance costs could add 3.5 ¢!lb of refined lead, and proposed regulations could add another 1.3 ¢!lb. The individual capital costs necessary to comply with pending environmental regulations are estimated to be $1.8 million for small smelters and $10.4 million for large smelters. Proposed regulations could require additional expenditures from $1.9 million for small smelters to $4.9 million for large smelters. These cost estimates, based on average 1985 dollars, indicate that pending and proposed legislation could add significantly to capital and operating costs of the secondary lead industry. These regulatory compliance costs may result in a loss of up to 40 pet of secondary lead production capacity.

Jan 1, 1987

By M. M. Fine

"INTRODUCTION One of the principal activities of the Bureau of Mines during the recent war was to help to increase the supply of strategic and critical minerals. Fluorite was one of the most critical of the nonmetallic minerals because of the increased demand for it as a flux in basic open-hearth and electric steel furnaces and as a raw material for the production of artificial cryolite used in the aluminum industry. Wartime developments in the technology of hydro-fluoric acid, such as the use of the anhydrous acid as a catalyst in high-octane-gasoline production and the use of organic fluorides as carriers for insecticides, also increased the demand for acid-grade fluorspar. 2/ In 1943 the consumption of acid-grade fluorspar was advancing at a more rapid rate than production and was only slightly less than production during the latter half of the year.The outlook for the postwar market for fluorspar is encouraging. Steel production is expected to remain high until the domestic demand for commodities not manufactured during the war is satisfied. The uses for hydrofluoric acid also are expected to increase under the impetus of war-initiated research. In consideration of these and other factors some authorities predict a new peacetime demand for fluorspar equal to 60 to 75 percent of the war production, 5/ 6/ and others believe that the fluorspar industry will be permanently expanded. 7/"

Dec 1, 1947