Search Documents

By J. D. Davis

From the chemist's point of view it would be ideal if specifications for coke for any stated purpose could be written on the basis of chemical composition and burning characteristics. Unfortunately this is not possible. In fact, the physical properties of a coke are often of such major importance as to render any specified chemical requirements totally inadequate to show the quality of coke desired. For example, a furnace coke may admirably fill all chemical requirements, such as for low phosphorus, sulphur, moisture, and high fixed carbon, and still be too soft to support the burden of the furnace without excessive crushing. Again, a domestic coke though a good fuel as judged from Chemical analysis, may be of unmarketable size. Thus one can not define the quality of a coke for a specified purpose without taking into account both its chemical and physical characteristics even when this has been done the specification may fail because neither coke user nor producer can accurately define by quantitative tests the qualities most desired. In other words, there is need of accurate test methods for measuring the properties of coke and, what is equally important, for correlating the results with the behavior of the coke in use. Coke quality is determined by the kind of coal used, the coking process, and the type of equipment used in the coking process. Chemical analysis of the coals, together with small-scale coking tests, will give a good indication of their suitability; but, in general, coke must be produced on an industrial scale and tested in the equipment for which it is intended before conclusive information as to its quality is obtained.

Jan 1, 1928

Provide a strategy for calculating optimum distribution of selected sensors for detecting underground mine fires. Approach The Bureau of Mines performed research to determine adequate distribution of product-of-combustion (POC) fire sensors within mine entries. This placement strategy would improve the miner's chances for escape by locating sensors where they would most effectively, quickly, and efficiently detect fires resulting from coal or wood combustion. Spacing of Sensors Placement strategy guidelines were based on the performance of 160 F heat sensors with ideal operating characteristics which were placed at intervals of ten feet in underground mine entries. Data obtained from full-scale mine fires were used to estimate fire sizes and alarm activation times for the heat sensors. Various equations were then developed to determine spacing requirements for any fire detection system installed in entries of varying heights, widths, and ventilation rates.

Jan 1, 1983

By Steven J. Page

The increasing concern for dust control in metal and nonmetal mining prompted the Bureau of Mines to investigate the comparative effectiveness of three wet dust control techniques for face drilling. Previous attempts to achieve effective dust control on face drills with dry collectors have not met with success, the largest problem being sustained effective dust capture at the face. Results show that (1) foam-through-the-drill can provide 95-pct average total dust reduction in gypsum; (2) water mist-through-the-drill can provide approximately 91-pct average total dust reduction and 93-pet average respirable dust reduction in salt; (3) external boom-mounted water sprays can provide approximately 50-pet average dust reduction for both total and respirable dust in salt. The investigation showed that (1) foam and water in small quantities are very effective dust control techniques for face drills when applied through the drill steel at the point of dust generation, and (2) boom-mounted water sprays are only minimally effective for dust control on face drills.

Jan 1, 1981

By K. J. Liles

To encourage the development and conservation of the Nation's ceramic raw materials, the Bureau of Mines, U.S. Department of the Interior, under an agreement with the Georgia Department of Natural Resources, evaluated samples from a clay resource located in Clay County, Ga., for use as a raw material for lightweight aggregate. The physical properties of clay samples, taken from 5-foot increments of drill cores from 11 holes, were determined. Raw materials were plasticized and extruded to produce 1/2-inch by 1-inch pieces and fired in a rotary kiln to produce lightweight aggregate samples. The resulting expanded material had excellent loose pour weights ranging from 30 to 37 lb/cu ft. The expanded test materials were crushed, sized, and used as aggregate to form concrete cylinders. The unit weight and compressive strength of the cylinders averaged 106 lb/cu ft and 3,350 lb/sq in, respectively; these values meet American Society for Testing and Materials specifications for structural concrete. The clay from the drill cores was also used to make test bars that were evaluated for building brick.

Jan 1, 1980

By M. L. Davis

The principal causes of many methane-gas explosions that have occurred in anthracite mines, especially in thick pitching veins, during recent years can be traced to lack of a satisfactory method of testing for such gas in areas adjacent to those in which blasting is to be done or other sources of ignition introduced. As coal-mine officials and inspectors are required to make examinations for methane in all accessible open workings, including high places, and permissible flame safety lamps have been used almost universally for making these examinations, considerable difficulty has been experienced in proper testing of atmospheres at elevations beyond the normal reach of the examiner, and resultant explosions have often indicated perfunctory tests. The accepted practice of testing for gas in voids or high places generally consists of raising a flame safety lamp, suspended from the end of a long drill, stick, or pipe, into the atmosphere to be tested. Disadvantages noted are: Action of the flame within the lamp cannot be seen readily when the lamp is more then 18 inches overhead, the flame will not be extinguished when less than about 4-1/2 percent of methane is present, and indications of small percentages of methane within the lamp may disappear entirely while the lamp is being lowered slowly to view; the examiner must usually be exposed unnecessarily to falling material; and the lamp may fall and be broken. Thus, the need for a more reliable, safe method of testing for gas in out-of-reach places is apparent. Several electrical methane detectors, tested and approved by the Bureau of Mines, have been used satisfactorily, though infrequently, for making the aforementioned gas tests. Some of these detectors employ a rubber aspirator bulb and rubber tubing of suitable length to draw the atmosphere from high places through and over energized parts of the detector. However, the original expense, susceptibility to damage, and awkwardness of tarrying these instruments in steep-pitch workings has precluded their general use in everyday examinations. Although not as efficient as the electrical detector for determining small percentages of methane or as reliable because of the limitations imposed by oxygen-deficient atmospheres, the modern per¬missible flame safety lamp can, it is believed, be used safely with the rubber aspirator bulb and tubing to greater advantage and with comparative reliability in testing for gas in out-of-reach places. Slight reference to this method of introducing air into a safety lamp is made in a Bureau of Mines publication of l921,2/ and it is quite possible that the method has been utilized in some manner by individuals in American mines during the intervening years. A similar method was used in connection with a nonpermissible Wolf flame safety lamp in at least one coal mine in Japan before World War II. A major change in the construction of this lamp would bar its approval by the Bureau of Mines. An American adaptation of the Wolf lamp, developed

Jan 1, 1954

By Gary L. Mowrey, William D. Monaghan, George F. Persetic, Gregory M. Molinda

Ground penetrating radar (GPR) has been investigated by the U.S. Bureau of Mines Pittsburgh Research Center for its potential to determine rod hazards in underground mines. GPR surveys were conducted at four field sites with accompanying ground truth to determine the value of GPR for roof hazard detection. The resolution of the current systems allows detection of gross roof fractures (>6A mm (>0.25 in) zone) or rider beds in coal measure roof. Data quality is not yet sufficient to detect small bed separations or subtle lithologics changes in the roof. Differences in data quality are discussed, as well as suggestion for collecting improved data.

Jan 1, 1996

By Alan H. Goode

The advancement of high-temperature drilling fluid technology for application in geothermal environments is part of the Bureau of Mines program for more efficient development of our Nation's energy resources. The bentonite constituent of water-base drilling fluids is sensitive to destabilization by high-temperature and salinity. A substitute material for bentonite, phosphate slime, which is reported to be saline resistant, was considered. These studies show that spray-dried slime suspensions have more favorable rheological behavior, but poorer filtration properties, as compared with bentonite suspensions.

Jan 1, 1975

By T. E. Green

The Bureau of Mines Heavy Metals Program emphasizes the need for improved analytical methods for gold determination. A commercially available ion exchange resin with high selectivity for gold was investigated as a potential method to collect gold from solution. The resin was found to quantitatively collect gold from acid solutions over a wide range of acid concentrations. Common metals were not collected by the resin nor did they seriously interfere with the collection of gold. X-ray spectrographic and neutron activation methods based on the use of papers containing this resin are proposed.

Jan 1, 1970

By T. J. Lutz, G. T. Homce

A standard Ford1 4600 agricultural tractor was converted to remote control to perform ASAE/SAE field upset tests (rear rollover and side rollover). This paper discusses the engineering process to develop a remote-controlled tractor in determining the critical parameters of operation, to choosing appropriate actuators, designing the circuitry to control them, installing the actuators on the tractor, testing the system for functionality and then conducting numerous overturn tests. The system uses off-the-shelf components for simplicity, replaceability, and economic concerns. The remote control system has withstood 21 tests to date with no failures and will continue to be used for at least three more years of testing.

By J. W. Horne

The United States Bureau of Mines in cooperation with the State of Colorado at the University of Colorado has conducted experiments to determine the amount and composition of the noncondensable cases evolved when crude shale oil is distilled under pressure. Hydrogen sulphide is one of the components found in the complex mixture of uses produced by the distillation of shale oil under pressure. This paper deals with the apparatus and method used in determining the amount of hydrogen sulphide evolved in the laboratory experimental cracking stills.

Jan 1, 1931

By Christopher C. Jobes, N. Kumar Kittusamy, Alan G. Mayton, Dean H. Ambrose

Researchers with the National Institute for Occupational Safety and Health (NIOSH) conducted a systematic study to evaluate seat designs on low- and mid-coal-seam shuttle cars. The purpose was to gather additional data to support earlier findings that NIOSH seats, with unique viscoelastic foam padding, are indeed improved designs for coal mine shuttle cars. This study included a larger sample of shuttle car operators than a prior NIOSH investigation. Eight shuttle car operators participated in evaluating seat designs on the basis of perceived levels of vehicle jarring/jolting and discomfort. Researchers then compared the operators’ perceptions with field-measured levels of vehicle jarring/jolting. Seven seat designs were evaluated on low- and mid-coal-seam shuttle cars during production operations at two underground coal mines in southern West Virginia. These seat designs comprised the one already in use on each vehicle and five NIOSH designs. Experimental data were collected using accelerometers, signal conditioning amplifiers, and filters connected to a data recorder, whereas subjective data were gathered via a visual analog scale (VAS) and a questionnaire. Field trials included shuttle cars operating under full- and no-load conditions. VAS responses indicated that NIOSH-designed seats performed better relative to comfort and isolation from vehicle jarring/jolting than the existing seats used in the shuttle cars. Both mid- and low-coal-seam shuttle car operators, during no-load and full-load conditions, rated lower levels of jarring/jolting with the NIOSH seat design. Questionnaire responses indicated that shuttle car operators rated NIOSH seat designs as more comfortable. Vehicle operators most frequently suggested the addition of armrests as a way to improve the seats on the mid-seam shuttle car. The quantitative levels of vehicle jarring/jolting for the no-load condition (more severe condition for vehicle operation) showed that NIOSH seats for the mid-coal-seam shuttle car performed better than the existing seat in terms of peak acceleration and crest factor. Similarly, for the low-coal-seam shuttle car, NIOSH seats performed better than the existing seat in terms of peak acceleration, root-mean-square (RMS) acceleration, and crest factor.

Jan 11, 2006

By John P. Gooch

Data for the ternary phase diagram for the system 1,1,2,2-tetrabromoethane/water/2-propanol at 25° C have been measured. Experimental methods used are described, and the complete ternary phase diagram is presented. A simple example is given to review the use of the ternary diagram.

Jan 1, 1972

By D. B. Taliaferro

An accurate knowledge of the water content of oil-bearing sands4/ now is recognized as an important factor in calculations of the flow of oil through the sands to producing wells and in the estimation of oil reserves. To this end the Bureau of Mines laboratories are using a method that is an adaptation of the A. S. T. M. method of determining the water content of petroleum products (1).5/ However, the apparatus and technique have been altered slightly, as described in this report, to increase the precision of the method without affecting the simplicity of procedure or speed with which determinations may be made. Until recently petroleum engineers, when estimating reserves assumed that the entire pore volume of the oil-saturated parts of producing sands was filled with oil, as it was generally thought that the oil, water, and gas in any formation had separated completely during geologic time into distinct layers because of their difference in density. In 1929 Lindthrop and Nickolaeff (12) reported experimental results from which they concluded that 22 to 30 percent of the pore volume of producing sands in the Grozay district, Russia, was filled with water when the fields were discovered. Since that time numerous investigators (5, 7, 8, 10) have found evidence of water in the sands of now oil-producing fields and old fields that never produced water with the oil.

Jan 1, 1940

By Larry J. Nicks

The Bureau of Mines is investigating the catalytic activity of rare-earth compounds to develop a catalyst for the cathode reaction of a hydrogen-oxygen fuel cell. This report presents the results of studies of the catalytic activities of lanthanide oxides for the oxidation of hydrogen at 150° to 250° C. Preliminary activity tests were made with approximately stoichiometric mixtures of hydrogen and oxygen diluted with helium. A series of tests was also run under oxygen-rich conditions in which specific rate constants and activation energies were determined. Variations in rate constants up to 2,000 times were observed for the various lanthanide oxides. The three most active catalysts were oxides of Ce, Pr, and Eu, having specific activities of 6.93 X 10-7, 4.88 X 10-7, and 4.06 X 10-7 moles H2.sec-1.m-2, respectively, at 200° C.

Jan 1, 1973

Determine the minimum waterflow rate needed for effective control of dust produced by cutting machines used to mine water-soluble ores. Approach Conventional wet-bar cutting techniques were studied to evaluate their dust control performance, and the optimum water flow needed for dust suppression was determined. Wet-bar type cutting techniques are used to help control mine dust by keeping the cutting chain wet. As the chain cuts the kerf, it dampens the dust produced by the cutting action at the point of generation. The Bureau, under contract, evaluated three basic wet-bar techniques, as shown in the diagram: water-trickle system A uses a gravity-feed or low-pressure (less than 50 psi) pump to send water through the bar and to discharge it at the bar tip. Water-spray system B uses a low-pressure spray nozzle located at the front of the cutter head. For protection the nozzle can be located within the cutter

Jan 1, 1982

By R. W. Van Dolah

The feasibility of formulating cap-sensitive slurry explosives for use in underground mines with potentially flammable gas atmospheres was examined. Formulations containing aluminum metal as sensitizer and sodium chloride to reduce incendivity were prepared; some were cap-sensitive and had adequate air-gap. Flaked aluminum metal rather than the atomized type proved to be the more effective sensitizing agent of the formulations tested for incendivity in the large gallery of the Bureau of Mines, some were found to be suitably nonincendive.

Jan 1, 1968

By H. H. Dewing

The Bureau of Mines conducted a laboratory-scale investigation of a technique that produces zinc sulfate and elemental sulfur from sphalerite concentrates by reaction with sulfuric acid at 175° to 200° C and ambient pressure. The objective of the investigation was to develop a hydrometallurgical method of producing zinc from sulfide concentrates that does not generate sulfur dioxide pollutants. Reaction with 80-to 85-pct sulfuric acid produced 4 moles of sulfur for every 3 moles of sphalerite reacted, with minimal production of sulfur gases under optimum conditions. More than 98 pct of the zinc was recovered as zinc sulfate after 3 hours at 175° C. The reaction mixture was leached with simulated spent zinc electrolyte containing 13-pct sulfuric acid to recover zinc sulfate from the insoluble, high-sulfur residue. Neutral zinc sulfate, which is required for electrolysis, was separated from the sulfuric acid solution by crystallization as ZnS04?7H20 at -10° C. Up to 80 pct of the water in the recycled electrolysis solution was removed by the crystallization process; evaporation was used to further concentrate the sulfuric acid for reuse in leaching sphalerite. Advantages of the proposed method over conven-tional roasting and leaching include virtual elimination of sulfur dioxide, production of a solid sulfur byproduct, and higher zinc recoveries due to elimination of zinc ferrite losses.

Jan 1, 1978

By John J. Sammarco

Computer-related accidents have caused injuries and fatalities in numerous applications. Normal Accident Theory (NAT) explains that these accidents are inevitable because of system complexity. Complex systems, such as computer-based systems, are highly interconnected, highly interactive, and tightly coupled. We do not have a scientific methodology to identify and quantify these complexities; specifically, NAT has not been operationalized for computer-based systems. Our research addressed this by operationalizing NAT for the system requirements of safety-related computer systems. It was theorized that there are two types of system complexity: external and internal. External complexity was characterized by three variables: system predictability, observability, and usability -the dependent variables; internal complexity was characterized by modeling system requirements with Software Cost Reduction dependency graphs, then quantifying model attributes using 15 graphtheoretical metrics the independent variables. Dependent variable data were obtained by having 32 subjects run simulations of our research test vehicle: the light control system (LCS). The LCS simulation tests used a cross-over design. Subject perceptions of these simulations were obtained by using a questionnaire. Canonical correlation analysis and structure correlations were used to test hypotheses 1 to 3 - the dependent variables predictability, observability, and usability do not correlate with the NAT complexity metrics. Five of 15 metrics proposed for NAT complexity correlated with the dependent data. These 5 metrics had structure correlations exceeding 0.25, standard errors < 0.10, and a 95% confidence interval. Therefore, the null hypotheses were rejected. A Wilcoxon signed ranks test was used to test hypotheses 4 to 6 - increasing NAT complexity increases system predictability, observability, and usability. The results showed that the dependent variables decreased as complexity increased. Therefore, null hypotheses 4 to 6 were rejected. Lastly, this work is a step forward to operationalize NAT for safety-related computer systems; however, limitations exist. Opportunities addressing these limitations and advancing NAT were identified. Lastly, the major contribution of this work is fundamental to scientific research - to gain knowledge through the discovery of relationship between the variables of interest. Specifically, NAT has been advanced by defining and quantifying complexity measures, and showing their inverse relationship to system predictability, observability, and usability.

By Gerrit V. R. Goodman, Charles D. Taylor, Edward D. Thimons, Jay F. Colinet

The importance of controlling respirable dust and methane gas levels in underground coal mining cannot be underestimated. While respirable dust can significantly affect the occupational health of underground coal miners, methane gas accumulations pose significant safety concerns for these same workers. Water sprays and machine mounted dust scrubbers offer effective control of respirable dust exposures and methane gas accumulations. Water must not only be applied carefully to avoid dust rollback to the machine operator but must create sufficient turbulence to remove dead zones that could contain high concentrations of methane gas. While the flooded-bed dust scrubber has been generally responsible for decreased worker exposures to respirable dusts, this device has proved effective in controlling methane levels at the face. This paper reviews practical applications of water sprays and dust scrubbers to control respirable dust and methane gas on continuous miner faces.

Jan 4, 2000

Locating subsurface conductive solutions is important for many applications, including in situ mining and environmental protection. Drilling boreholes for sampling is expensive and can increase contamination by mixing water from different aquifers. Various noninvasive geophysical methods are available, but previous comparisons were hampered by different methods being used at different sites or at different times. The U.S. Bureau of Mines (USBM) compared methods at one site using the same conductive solution to improve the reliability of the comparisons. Locating deep (> 100 m) solutions is most difficult, SO the USBM selected methods applicable for such depths. Objective Improve the ability to locate subsurface conductive solutions by evaluating and comparing applicable geophysical methods. Approach The experiment was performed cooperatively with other agencies to increase the number of methods studied. The USBM, the University of Arizona, Sandia National Laboratories, and Zonge Engineering and Research, Inc., conducted cooperative field tests of six electromagnetic (EM) geophysical methods to compare their effectiveness in detecting salt water brine of conductivity 3.6 S/m collecting at the water table, 157 m subsurface. The brine was injected through two boreholes. The test site was the University&apos;s San Xavier experimental mine near Tucson, AZ. Geophysical surveys using surface and surface-borehole, time-domain electromagnetics (TEM); surface controlled-source audiofrequency magnetotellurics (CSAMT); surface magnetic field ellipticity, surface-borehole, frequency-domain electromagnetics (FEM); and crosshole FEM were conducted before and during brine injection. A total of 110,000 I. of brine was injected over one week, but the effective target volume of brine was much smaller because of mixing with ground water and dispersion.

Jan 1, 1994