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By John Ward Smith

This paper describes and evaluates a method that the Federal Bureau of Mines used to determine the ultimate composition of the organic material in 10 samples of oil shale from the Mahogany zone of the Green River formation in Colorado and Utah. Since interest has centered on the Mahogany zone, the richest section of the deposit, these 10 samples were chosen to provide a broad representation of this zone with the objective of obtaining generally valid ultimate composition values. The most probable organic composition for the Mahogany zone and the 95-percent confidence limits for each component average (in weight-percent of organic material) are: Carbon 80.5 ± .4 Hydrogen 10.3 ± .1 Nitrogen 2.4 ± .1 Sulfur 1.0 ± .1 Oxygen 5.8 ± .5 As only minor variations in composition were observed, the organic material of this particular bed is quite similar over a wide geographic area.

Jan 1, 1961

By Glenn Adkins

This report characterizes pivoting joints in the structures of mining machinery and how the wear on the various components, i.e., pins, lugs, yokes and bushings, may affect the safety of mine personnel where these components are allowed to wear excessively before repair or replacement.

Jan 1, 1979

By J. L. Eakin

Systematic flooding was introduced into Nowata County, Okla., in May 1931. The results of this means of stimulating the nearly depleted Bartlesville reservoir in the county has been the subject of four Bureau of Mines Reports of Investigations.2-5/ This report presents a discussion of four full-scale water-flooding projects in the Delaware-Childers field and 1 pilot project in the Curl Creek field (fig. 1). All five plants have been in operation for only a few months. Although substantial increases in the rates of oil production have been obtained 1 by the injection of water, the projects are of particular interest at this time because of the novel methods of operation and new equipment that are being employed. One project utilizes a portable "package" plant designed for a pilot operation. All of the controls for this project are centrally located. The design makes it possible to remove the test plant to another location if the project is unsuccessful or if the unit is to be replaced by a larger plant. This project also utilizes diatomaceous-earth filters successfully for the first time and makes use of plastic pipe. Another novel feature of the operation is the aeration of Arbuckle limestone water through an airlift in the supply well.

Jan 1, 1955

By D. S. Burgess

This report summarizes the incidents that preceded the December 9, 1970, propane-air explosion in Port Hudson, Mo., and then attempts to establish the nature of the explosion from the ensuing events. Special emphasis is given to possible ignition sources, the distribution of flammable vapors, and the analysis of blast damage. Both near-and far-field damage indicated that this explosion may be attributed to the detonation of propane in air with an energy release equivalent to that from about 50 tons of detonating TNT.

Jan 1, 1973

Electrical trailing cables are frequently damaged in usage, especially on continuous minors, and because of their weight and damaged condition present a safety hazard to personnel required to handle them. The U.S. Bureau of Mines and FMC Corporation signed Contract No. HO 122011 in August 1971. One of the contract tasks was to study the feasibility of techniques to improve trailing cable support and handling of power cables on underground coal mine machinery and to design a cable-handling device for a continuous mining machine. This report presents the results of the feasibility study, describes the design for a proposed cable handling device and concludes with a recommendation for future action to construct a test rig to evaluate the cable reel system.

Jan 1, 1972

A symposium on the health hazards of respirable dust in the mining and milling of talc was held on May 8, 1973, in Washington, D.C. The results of medical effects on both human and animal subjects were presented. Methods for identification and classification of talc minerals were also presented. Analytical techniques discussed included X-ray diffraction, scanning electron microscope observation, electron probe, and optical microscopy.

Jan 1, 1974

By R. L. Gall

This report describes Bureau of Mines experiments in gasifying coal in a helium-heated tube-coil reactor. The purpose of this work was to investigate helium as a medium for transferring heat from a nuclear reactor to gasify coal or for use as high-temperature process heat. A laboratory-scale system was designed and constructed to demonstrate feasibility. In preliminary tests with this system, in which the coal was fed as a water slurry, the helium-heating and recycling equipment operated well. Considerable difficulty was experienced, however, in preheating coal slurry to the desired range of 400° - 1,000° F. without plugging the preheaters. Five different preheaters plugged with coke or with salts leached from the coal. The longest operating period wan 12 hours. These difficulties were partly due to the relatively small equipment and flow rates. The gasifier processed l pound per hour of low-rank coal at 300 p.s.i.g. and 1,800° F., with the carbon conversion limited to 20 to 30 percent by the short residence time and slow heat-transfer rate.

Jan 1, 1962

By Robert H. Peters

Several significant problems associated with employee turnover among underground miners are described in this Bureau of Mines report. Although a vast amount of research has been conducted on turnover among employees in nonmining industries, there has never been an attempt to empirically investigate the causes of turnover among underground miners. This report presents the results of empirical research on employee turnover in other industries and describes and critiques the research methods that have been used to investigate turnover. Using the findings on employee turnover in other industries and known data about miners and the mining industry, a conceptual model of the factors that cause turnover among miners was generated. This model, which is expected to provide a basis for later empirical studies, is presented. Several recommendations for controlling miner turnover are also presented.

Jan 1, 1986

By R. A. Friedel, J. L. Shultz, A. G. Sharkey

The purpose of this investigation was to study the primary materials associated with the coal structure . Mass spectrometric techniques can be useful in studying the chemical structure of coal and various high- molecularweight materials derived from coal . Investigations of pyrolysis products and extracts of coal , and also whole coal , showed : 1. Aromatic hydrocarbons obtained by the vacuum pyrolysis of coal below 300 ° C possibly were sorbed material rather than decomposition products . 2 . 2 . Thirteen structural types having molecular weights from 78 to 400 were identified in pyridine extracts constituting one - quarter or more of the coal by weight . 3. Material extracted at room temperature with a methanol - benzene solvent and a vacuum pyrolysis condensate obtained at 450 ° C contain similar components . The extract and the condensate have approximately the same average molecular weights ( 200-300 ) . 4. Material extracted from coal at room temperature is altered even by mild thermal treatment . 5. Changes in various alkyl series occurring in thermally treated coal extracts can be followed quantitatively . 6. Similarities in the spectra of coal and graphite were indicated in an investigation using a mass spectrometer equipped with a spark source . Determinations on a coal - ash sample by this technique showed good agreement with data obtained by emission spectroscopy .

Jan 1, 1963

By Rolland L. Blake

Petrographic and mineralogical studies were made on unoxidized samples from the Cuyuna and Mesabi districts to study occurrence and properties of the iron phyllosilicate minerals . Examination of 96 thin sections from the thinbedded facies of the main iron - formation of the Cuyuna district indicates that the most abundant minerals are Mn - Mg - siderite , stilpnome lane , and minnesotaite . Reconstitution and recrystallization of minerals has occurred along certain beds , and textures indicate that some minnesotaite apparently formed at expense of stilpnomelane . Three samples of stilpnome lane and one of minnesotaite were concentrated from fracture - fillings within iron- formation . Results of chemical , optical , spectrographic , X- ray diffraction , and differential thermal analyses on these samples are reported . The detection of ammonia in stilpnome lane samples is the first such occurrence reported , and its significance is discussed . New mineral data are presented on greenalite and probable septechamosite from the Mesabi district .

Jan 1, 1964

Case 1: A driller raised a drill rig mast into a 7200-volt overhead power line. Both he and his helper were killed. Case 2: A driller-helper was pulling a winch cable toward a stack of drill steel when the cable contacted a 12,000-volt power line. The helper was killed, and the driller at the rig controls was severely injured. [ ]

Jan 1, 2006

Reduce well construction and operation costs associated with in situ leach mining while increasing mineral recovery. Approach To accommodate the size of centrifugal pumps presently in use, in situ leaching production wells are typically drilled to 6 inches in diameter, while monitor wells are drilled to measure 4 inches in diameter. However, in order to reduce the cost of drilling these larger diameter wells and to increase recovery, the Bureau has developed jet pumps which have smaller diameters than centrifugal pumps of the same capacity. This allows both production and monitor wells to be drilled smaller. Bureau estimates indicate that the cost of drilling a 3-inch-diameter production well at in situ leaching operations would be about 35 percent less than the cost of a 6-inch well. Similarly, the cost of drilling a 2-inch-diameter monitor well would be about 26 percent less than the cost of a 4-inch well. Such significant savings in the cost of drilling these wells would effect a substantial reduction in total capital cost. Use of the new jet pumps can also increase the percentage of recovery because less costly wells allow closer well spacings, improving the distribution of the leach solution. How the System Works After the borehole is cased, the new small-diameter jet pump, along with piping and accessories, is installed and connected to a centrifugal pumping unit on the surface. High-pressure water from the surface pump is forced through a nozzle into the venturi of the jet type pump injector. This jet action lifts the leach and mineral-bearing solution to the surface.

Jan 1, 1984

By Michael S. Contratto, Dave Marshall, Tom Brodersen

The European Union (EU) completed a new directive 2002/44/EC1 called the Physical Agents Directive (PAD) that establishes action and limit values for hand-arm and whole body vibrations. The directive specifies that: “…workers shall not be exposed above the exposure ‘limit value’.” 1 and “…once the exposure action values … are exceeded, the employer shall establish and implement a programme of technical and/or organisational measures intended to reduce to a minimum exposure to mechanical vibration and the attendant risks…” 1 The PAD limit value is effective for new machines starting July 6, 2007 and for used machines by at least July 6, 2010. These requirements apply to the users of machines, but machine manufacturers will be challenged to provide machines and information to help the users comply with the directive. Caterpillar manufactures machines with the goal of enabling our customers to comply with all regulations dealing with health and safety. Caterpillar designs all of our machines to provide a safe, comfortable and productive work environment. This study was to determine if seat suspensions could provide a reduction in the vibration environment experienced by operators of Caterpillar mid sized (<50,000KG) Track Type Tractors Methods Seat manufacturers were asked to provide seat suspensions that provide improved isolation over and above current seat suspension. Each supplier was provided with ride profiles and was asked to demonstrate the vibration reduction on a shaker table. Two suppliers provided suspensions that were compared with the current seat suspension in a field study. Three full factorial experiments were conducted. The first experiment was to evaluate overall suspension performance for four operations. The second experiment was to determine the benefit of the adjustable vertical damper at three different levels and the third experiment was to determine the effect of the fore/aft and side/side isolators. Six operators were used for the study. Acceleration was measured at the seat base and at the operator seat pad. Both the transfer function and the ISO 2631 RMS ride values were used to determine the seat suspension’s effectiveness of isolating the operator from vibration. A structured questionnaire was used to determine the operators’ subjective assessment of the seat suspensions. Results There was significant operator-to-operator variability in the vertical direction (>35%), however there was little variability in the fore/aft and side/side direction based on seat base

Jan 6, 2006

Papers presented at a U.S. Bureau of Mines (USBM) technology transfer seminar describe the causes of violent material failure in U.S. mines, measurement techniques for monitoring events that result in violent failure, and mitigation techniques for controlling failure. Specific factors contributing to violent failure are identified on the basis of geotechnical monitoring in 16 U.S. hard-rock and coal mines and on statistical analyses of 172 coal bump events. New monitoring and analysis techniques developed as tools for assessing violent failure; geotomographic methods that provide new capabilities for the study of material failure and stress changes over large areas; and seismic methods for determining source locations, calculating energy release, and determining source mechanisms are described. Fair correlations have been established among seismic parameters, elastic stresses, face support load, and violent events. USBM studies have identified the advantages using both yielding and stable pillars for coal bump control. A computer program has been developed as an aid for selecting room-and-pillar layouts. The practical aspects of implementing a destressing program is outlined for coal mines, while the importance of mine orientation and timely support installation in controlling buckling-type failure is identified for hard-rock mines.

Jan 1, 1995

By Gerald P. Scanlan

Control of the dust produced by continuous mining machines in coal mines is generally obtained by water sprays from fixed nozzles mounted on the frame of the machine in back of the cutting head. Mounting the nozzles on the rotating head of the machine closer to the coal cutting bits may improve the efficiency of dust suppression. To test this concept, respirable dust measurements were made during 39 regular production shifts in an underground mine using a Joy 11CM continuous miner. The equipment used, difficulties encountered, and measurements obtained are described.

Jan 1, 1974

By D. R. Wilburn

The Bureau of Mines investigated the potential availability of magnesium from 45 properties in market economy countries (MEC&apos;s). The 38 significant deposits evaluated have demonstrated resources of approximately 29 billion short tons (st) magnesium-bearing material containing 416 million short tons (MMst) magnesium oxide (MgO). Using data it gathered, the Bureau determined the magnesium production potential for each property including a 15-pct rate of return on invested capital. Total and annual availability assessments for the next 30 yr were completed for magnesium (Mg) metal, deadburned MgO, and caustic calcined MgO. At a January 1984 market price of $1.34/Ib Mg metal, the properties evaluated could economically produce an estimated 13 MMst Mg metal. At a market price of $400/st nonmetal magnesium product, these properties could economically produce 109 MMst deadburned MgO and 43 MMst caustic MgO. These properties could produce approximately 301,000 st Mg metal, 3.0 MMst deadburned MgO, and 430,000 st caustic MgO annually at current full production levels and 1984 market prices until at least the year 2000. Total 1984 MEC production assessed in this study was 153,000 st Mg metal and 4.3 MMst nonmetallic MgO products.

Jan 1, 1986

By S. Kraemer

Consumption of plastics has been growing in both the U.S. and world markets since the mid-1930s. This growth is due to plastics being used to make new products and as a replacement material for existing products. This paper develops an understanding of the replacement process by looking at the use of plastic, specifically PVC, in the construction pipe industry. History details the growth of the plastics industry and a discussion of the material selection process indicates the advantages and disadvantages of plastic pipe. Analysis shows that the use of plastic, as an alternative material for pipe, is having a significant effect on the cast iron, copper, clay, and steel industries. For the purpose of understanding the replacement process, three example residential systems were examined with a lifecycle cost analysis being performed. PVC was the material of choice in 1988 for all systems. Even though disposal cost was the one area where PVC was not the most cost effective, disposal costs were not sufficient to offset the overall advantage of using PVC on an economic basis. That plastic competes effectively with other materials, in terms of material properties and cost, indicates that further work should be performed to understand the impact plastics have on other material markets.

Jan 1, 1991

By Irvin G. Burough

ANDROS INCORPORATED has designed, manufactured and delivered four handheld C02 DETECTORS and three handheld CH4 DETECTORS. These instruments are for in-mine safety use. The DETECTORS incorporated an NDIR optical/electronic analyzer design in which exceptional zero stability is achieved by pressure modulation of the sample gas. This eliminates the need for daily calibration. This stability and the miniature design (2.5" x 4.5" x 4.5"; 4.5 lbs) of the C02/CH4 DETECTORS provide practical instruments suitable for routine safety inspections. This report includes the theory and design of the instruments as well as studies of gas-pressure modulation by a piezoceramic-driven Helmholtz resonator.

Jan 1, 1979

By Jos. R. Guiteras

This paper describes the pumping operations at the Ajax, Cresson, and Vindicator dines in the Cripple Creek mining district of Colorado during the summer of 1936. At that time the three mines wore pumping 6,500 gallons of water per minute into the Roosevelt drainage tunnel. Cripple Creek is the most important gold district in the State; it has yielded gold valued at over $365,000,000. The mines engaged in pumping are among the largest producing properties in the district. ACKNOWLEDGMENTS The author wishes to acknowledge the friendly cooperation of mine officials at the properties visited. At the. Ajax mine information was courteously given by Clayton Kissel, mine superintendent, and his staff; R. Y. Roby contributed the drawings. For information on the Cresson mine, thanks are expressed to Al H. Bebee, mine superintendent, and his staff, especially to Guy Rorabaugh, master mechanic, and to engineer Carlton. At the Vindicator mine, J. S. Anderson; mine superintendent, and Robert Welch, master mechanic, assisted; the latter furnished most of the information about that mine. Acknowledgment is also made of the cooperation of M. H. Salsbury, engineer at the Portland mine, who supplied technical data on the Roosevelt drainage tunnel.

Jan 1, 1937

By T. E. Bernard

The CO2-absorbent canisters used in four approved rescue breathing apparatus were investigated. A breathing machine was used to simulate human expiration with gas flow rates of 26, 37, and 48 1/min of 3.5% CO2 in air. The exit gas CO2 concentration, the pressure drop across the canister, and the exit-gas temperature were monitored. The absorbent capacities of the packed-bed canister designs were found to be dependent on flow rate within the range studied, while the capacities of the other designs were less affected. The radial canister had the least resistance to breathing while the complex bed design proved to be the most effective in utilization of the chemical. The overall results indicated that LiOH (lithium hydroxide) has the highest capacity for CO2 absorption among the absorbents tested. It can be used in a simple packed-bed design while maintaining acceptable levels of resistance and exit-gas temperature. Examination of oxygen supply with respect to CO2-absorption capacity suggested that it is desirable to closely match CO2-absorption capacity with the avail-able O2 supply to minimize the size and weight of rescue breathing apparatus.

Jan 1, 1979