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By S. Gallagher, A. G. Mayton

Back injuries account for a high proportion of lost workdays in the mining industry and are a leading cause of disability in mine workers. Two risk factors for low back injuries are manual lifting and whole-body vibration exposure when operating mobile equipment. Recent research has shed light on possible mechanisms through which low back injuries may occur, and the results of these studies can be used to improve the design of lifting tasks and seats to decrease injury risk. This article discusses recent research results and how this knowledge can be leveraged to reduce the risk of low back pain.

By W. S. Landers

This report presents a detailed study of low temperature, entrained-bed carbonization of an Australian coking coal. The coal studied was high-volatile B bituminous from the Foybrook mine, an open-cut operation in the Liddell seam, New South Wales, Australia. Carbonization was conducted in an 8-inch diameter, continuous vertical reactor at several temperatures from 960° to 1,300° F. It was demonstrated that this bituminous coal can be carbonized within this temperature range to produce tar and a nonagglomerated char, without prior oxidation or char recirculation. Carbonization rates from 138 to 287 lb/hr (as-carbonized basis) were investigated. It was found that the carbonization temperature and the air-to-coal ratio must exceed minimum values to insure continuous operation. At the higher air-to-coal ratios employed, all or most of the carbonization heat was provided by internal combustion with air in the reactor. At the lower air-to-coa1 ratios, part of the heat for carbonization was supplied externally. On the moisture-and ash-free basis, the yield of tar plus light oil ranged from about 26 to 44 gallons per ton, and the char yield ranged from approximately 1,160 to 1,370 pounds per ton. The heat in the gas ranged from about 900 to 3,000 Btu/lb of moisture-and ash-free coal. Carbonization product yields correlated well with air-to-coal ratio and carbonization temperatures. The volatile matter in the char was found to be temperature dependent. At 1,300° F carbonization, the volatile matter in the char was 8.7 percent (dry basis), whereas at 9600 F carbonization, the residual volatile matter was about 16 to 18 percent (dry basis).

Jan 1, 1965

By Larry A. Haas

Carbonyl sulfide (COS) was decomposed to sulfur and CO in a silent electrical discharge. A threshold of about 4 kv at 60 Hz was required to dissociate the gas in a laboratory ozonizer at 790 torr with electrode gaps between 1 and 5.5 mm. Above the threshold value, the reaction rate increased with increasing voltage with helium or nitrogen diluent. With the latter diluent, higher voltages had to be applied to obtain the same yield in the 4-to 12-kv range. The COS decomposition rate increased with COS concentration, but a saturation value was reached at about 10 pct COS. The reaction rate decreased at low linear gas velocities as obtained at lower gas flows, larger electrode gaps, or larger reactor volumes. Increasing gas temperature also decreased the decomposition rate. The presence of solid adsorbents such as quartz wool, bauxite, or charcoal had no significant effect on the reaction rate. The addition of S02 did not affect the COS decomposition rate, but small amounts of water decreased the reaction rate. Over 50 pct of the COS was decomposed at room temperature and atmospheric pressure in a l7-kv ozonizer using a gas containing 0.9 pct COS in helium flowing at a rate of 0.3 liter/min. The average current was less than 5 ma. This method has possible application in eliminating the toxic air pollutant, COS, which is generated in petroleum refineries and in processes involving reactions between sulfurous and carbonaceous materials. Carbon monoxide that is formed can be further oxidized to CO2 after the collection of elemental sulfur.

Jan 1, 1972

The Bureau of Mines conducted a field study of respirable dust concentrations at an underground room-and-pillar oil shale mine and at the aboveground milling facility to determine the dust generation sources, personal respirable exposure, characteristic minerals, and size distribution of the dust. Major dust sources in the mine were the scaling and blasthole drilling operations, and major dust sources in the processing mill were the screening and crushing operations. Principal minerals found in the airborne respirable dust were albite, analcite, calcite, dolomite, quartz, and orthoclase. The average alpha-quartz content of mine and mill respirable dust samples was 4.1 pct and 15.5 pct, respectively. Carbonaceous material such as diesel particulate accounted for approximately 75 pct of the respirable particulate found in the mine. The average coefficient of variance of respirable dust concentrations measured with approved personal dust samplers in the mine and mill was 7.6 pct, the best precision observed to date with the personal dust sampler operated in the field.

Jan 1, 1977

By Forrest T. Moyer

INJURY experience and employment data are presented in this chapter for metal and nonmetal mines, stone quarries, sand and gravel pits, iron blast-furnace slag plants, and metallurgical plants (including ore-dressing and nonferrous reduction plants and refineries) in the United States. Employment and injury experience data for all mineral industries are given in volume II. The 1962 figures are preliminary summations which are subject to revision. They were compiled from all reports from producers received by the Bureau of Mines through April 15, 1963. The data for metal, nonmetal (except well and brine operations), stone, and sand and gravel operations were collected by a mandatory reporting system under the provisions of the act of September 26, 1961, Public Law 87-300 (75 Stat. 649). The act authorized the Secretary of the Interior to study the various aspects of safety in metal and nonmetal mines (excluding coal mines) and report the findings 2 years sub-sequent to the enactment of the law. Data on nonmetal well and brine plants and nonferrous reduction plants and refineries were reported voluntarily by the operators. METAL MINES Preliminary data for the metal mining industry comprise reports on 1,871 mines and pits. The combined fatal and nonfatal injury-frequency rate was 31.95 per million manhours in 1962, a decrease of 8 percent from the similar rate of 34.54 in 1961. Metal operations reported a total of 61 fatal and 3,201 nonfatal injuries.

Jan 1, 1963

By Frank D. Lamb

Pyrophyllite, a hydrous aluminum silicate (Al2 Si4O10 (OH)2 ) has been mined in North Carolina and marketed without beneficiation for the past 100 years, but recent demands for higher-grade material indicate that an economical concentration method is needed for at least a part of the pyrophyllite production. Past production has depended upon selective mining and hand sorting, which is often unsatisfactory because of the finely disseminated character of the ores. The major impurity in North Carolina pyrophyllite ores is quartz, which accounts for the abrasiveness of the commercial product. Since pyrophyllite is only slightly heavier than quartz, those ores cannot be beneficiated by simple gravity-concentration methods. Some separation can be attained by differential grinding and air classification because of the difference in hardness of the two minerals) but the separation is not sharp. Froth flotation of pyrophyllite from Quartz has never been attempted commercially, but if the demand for high-grade material is sufficient, it would seem that this process offers the most premise of being economically feasible.

Jan 1, 1950

By James V. Kelly

"INTRODUCTION In the course of Bureau of Mines investigations of iron ores near Scappoose, Columbia County, Oreg. during 1942, occurrences of laterite were noted in road cuts and outcrops at many localities in the county. In 1944, the State of Oregon Department of Geology and Mineral Industries completed a preliminary examination of alumina-iron-bearing laterite occurrences in Washington County north of Hillsboro, Oreg.3/ Their report suggested that the lateritic material might be amenable to treatment by the Pederson process for the commercial production of iron and alumina. In order to determine the extent and character of some of the reported lateritic occurrences, the Bureau conducted preliminary explorations in Columbia County near St. Helens, Oreg., from January through June 1945. Almost simultaneously the Alcoa Mining Co. began to explore nearby areas. Their work was continued and expanded after the Bureau's work had been discontinued. This report presents the data obtained from the exploratory work of the Bureau of Mines.ACKNOWLEDGMENTSIn its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral re¬sources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, O. C. Ralston, chief, analyzes samples and performs beneficiation tests.Samples were assayed at the Reno, Nev., laboratories of the Bureau of Mines under the supervision of A. C. Rice, acting supervising engineer, and at the Albany, Oreg., laboratories under the supervision of Dr. B. A. Rogers, chief, Albany Division, Metallurgical Branch."

May 1, 1947

By Stephen Gerard Sawyer

This report presents a Fortran IV computer program for the structural analysis of space-frame protective canopies used in underground mines to protect equipment operators from falls of roof, face, or rib. This program entitled CANOPY permits rapid calculation of the elastic strength of a canopy for a variety of static loading conditions. Stresses in, and displacements of each structural member are computed and printed out. Additionally, identification of all members that have commenced yielding, weight of the canopy, total loads on the canopy, and maximum loads that the canopy can sustain elastically are output. Program description, input instructions, program listing, and two example problems are included.

Jan 1, 1972

By D. W. Scott

Thermodynamics is a powerful tool for investigating rotational isomerism in substituted ethanes and related molecules. Accurate calorimetric data can be interpreted to give information, not only about the energy difference between conformations, but also about the shape of the potential barrier hindering rotation from one conformation to another. However, a deterrent to this use of thermodynamics is the labor required to calculate the contributions to the thermodynamic functions for assumed potential functions. Tables of thermo-dynamic contributions for appropriate potential functions can eliminate that labor and greatly facilitate the thermodynamic study of rotational isomerism. In this research, tables of contributions to the thermodynamic functions were compiled for two potential functions typical of some commonly encountered examples of rotational isomerism. TYPES OF POTENTIAL FUNCTIONS Potential function 1, illustrated in figure 1, A, has two equal minima higher than the third. It has the general shape of the barrier to internal rotation in n-butane, for example. The trans conformation of n-butane has the lowest energy, and the two skew or gauche conformations have equal but higher energy. Potential function2, illustrated in figure 1, B, has two equal minima lower than the third. It has the general shape of the barrier in 2-methylbutane, for example. The two C1 conformations of 2-methylbutane have equal energy much lower than the assumed Cs conformation, which has not been observed spectroscopically.

Jan 1, 1962

By Oliver C. Fursman, Lloyd H. Banning

This research was undertaken to determine the feasibility of producing steel from hydrogen - reduced , pyrophoric iron powder . Before steelmaking tests were begun , investigations were made to develop procedures for handling the pyrophoric powder safely , and melting tests were made in a single - phase , electric - arc furnace to determine inert gas requirements for preventing powder oxidation . Steelmaking tests were conducted in a conventional electric - arc furnace , usually by a two - slag basic procedure . Results of the research indicated that ( 1 ) pyrophoric powder can be handled safely and can be prevented from oxidizing excessively during charging and melting in electric - arc steelmaking furnaces ; ( 2 ) little , if any , more electrical energy is required for melting Cerro Bolivar iron powder per unit of contained iron than is required for melting heavy melting scrap ; ( 3 ) high - quality steel can be produced readily from high- grade iron powder , having recoveries up to 95 percent of the total iron ; ( 4 ) steel can be produced from simulated titaniferous , chromiferous , and manganiferous iron powders ; and ( 5 ) the electrical energy required for melting increases with increase in the proportion of slag - forming constituents in the furnace charge .

Jan 1, 1964

By Robert L. Lagace

This final report documents the work dune by Arthur D. Little, Inc. (ADL) on behalf of the U.S. Bureau of Mines, Pittsburgh Mining and Safety Research Center (PMSRC), on Contract H0122026 (which began in August of 1971). Under this contract ADL provided technical assistance to the Bureau on a task basis on virtually all aspects of the Bureau's programs related to present and planned emergency and operational communications and miner location systems for underground coal mines. The work consisted of independent investigations, analyses, experiments, breadboard and prototype hardware development, workshops and technology transfer seminars on mine communications, and on-going evaluations and guidance related to the Bureau's contracted programs on electromagnetic noise, mine communications systems, and trapped miner location. This final report documents the work in two volumes, Volume I, "Emergency and Operational Mine Communications," and Volume II, "Seismic Detection and Location of Isolated Miners." The Tables of Contents of both Volumes are included in each Volume. Phase I of the contract was devoted to performing an in-depth assessment of electromagnetic noise measurements taken by several contractors and other investigators, and then defining a new noise measurement program and instrumentation system tailored to obtain the necessary but missing noise data. These data are required for use in the design of new emergency and operational communication systems. This work, and the follow-on coordination and guidance activities of ADL on this noise measurement program in subsequent phases of the contract, are treated in Part One of Volume I.

Jan 1, 1974

By Launa Mallett, Charles Vaught, Michael J. Brnich

Purpose: This training material focuses on the content of emergency warning messages. Research has shown that when an emergency occurs, people often do not get the information they need for the purpose of taking appropriate action. This safety talk presents a procedure, using mental cues that can be used by senders and receivers of emergency warnings. Intended Use: This material has been developed for use in short safety-training sessions such as start-of-shift safety or Atoolbox@ talks. The information can be presented in approximately fifteen minutes and is appropriate for workers at all experience levels. While the examples and illustrations are taken from the underground coal mining industry, the training can be tailored to any work setting by substituting appropriate examples. Materials Needed: The instructor will need to prepare the figures provided in a form that can be seen by the entire class. Suggested methods include the use of: (1) overhead transparencies, (2) laminated pages that can be held up for small groups, and/or (3) handouts with copies of the figures for each trainee. As a supplement, stickers featuring the communication triangle can be placed on hard hats, telephones or other communication devices to remind workers about the key to effective emergency communication. The Talk: The accompanying script is a guide for presenting this safety talk. Training is enhanced if these materials are covered but not simply read by the trainer. Examples given in this guide are from real experiences. To make training more interesting and effective, the instructor can substitute examples from his/her workplace. Additional Resources: The following references will provide further information about communications during emergencies. Auf Der Heide, E. (1989). Disaster Response: Principles of Preparation and Coordination. The C.V. Mosby Company, St. Louis. Mallett, Launa, Charles Vaught, and Michael J. Brnich Jr. (1993). A Sociotechnical Communication in an Underground Mine Fire: A Study of Warning Messages During an Emergency Evacuation@, Safety Science, 16, pp. 709-728. Nigg, J.M. (1987). A Communication and Behavior: Organizational and Individual Response to Warnings@ in Sociology of Disasters: Contributions of Sociology to Disaster Research, R.R. Dynes, B. De Marchi, and C. Pelanda (eds.), Franco Angeli, Milan, Italy, pp. 103-116.

Jan 10, 1999

By E. G. King

This publication presents original thermal data for a typical variety of perlite and supplies basic information for use in computing energy requirements in processes for expanding perlite. Perlite has been defined by Raiston 4/ as any silicious lava containing dissolved water in sufficient amount to errand into bubbles when the material is quickly heated to a suitable point in the softening range." The uses of expanded perlite in) the construction and ceramic industries have been discussed by Ralston 4/ and King. 5/ The work described here had a dual purpose: (1) It was desired to ascertain quantitatively, using a typical variety of perlite, just how firmly the contained water is held, and (2) it was desired to obtain basic thermal data sufficient for energy-requirement calculations in processes for expanding perlite.

Jan 1, 1948

By R. V. Ramani

This report is volume 2 of an eleven-volume final report for a Grant completed by The Pennsylvania State University for the Bureau of Mines to develop a dynamic general purpose computer simulation model for underground coal mining. The simulator developed under the Grant has a wide range of possible applications in the design and evaluation of underground coal mining systems from the standpoints of health and safety, productivity, and mine environment. The Master Design Simulator consists of nine free-standing function-oriented subsystem models linked together into an integrated, comprehensive model of an entire mining system. The subsystems comprising the Master Design Simulator include geology and reserves, methane generation, roof support, subsidence, production, rail haulage, cost, water generation, and ventilation. This volume of the final report describes the Geology and Reserves subsystem of the Master Design Simulator. The two functions of this subsystem are: 1) the design of a geological data library to provide input to the other subsystems of the simulator; and 2) the calculation of coal reserves and associated values and grades under various user-specified conditions. The subsystem uses a weighted moving average method to interpolate between the borehole values, and provides output in report format, graphical plots and/or storage on magnetic tape or other storage devices for later retrieval. The application of the subsystem as an independent model with test results and comparisons with other methods of computing reserves is also presented. The appendix comprises a users manual for the model, and includes a program listing.

Jan 1, 1974

By Todd M. Ruff

Blind areas around construction equipment are a major contributing factor in incidents involving a piece of equipment striking a worker. In highway construction, these types of incidents result in an average of 22 deaths a year in the United States. The Spokane Research Laboratory of the National Institute for Occupational Safety and Health, in cooperation with the Washington State Department of Transportation, is evaluating methods to decrease these incidents. One such method uses devices that assist equipment operators in monitoring blind areas around the equipment to prevent collisions with workers or other objects. Several camera and sensor systems are available for this application. These systems were evaluated on various trucks used in road construction and maintenance. Tests were conducted on sanding trucks during the winter months, which allowed researchers to investigate the effectiveness and limitations of various technologies under the most extreme conditions. Tests were also conducted on dump trucks and utility vehicles during the warmer months to study the effectiveness of the systems in highway work zones. Results showed that many difficulties arise when using camera and sensor systems in cold, snowy climates. And, while the operation of these systems is more reliable during the warmer months, challenges still exist in using them on equipment in congested work areas.

By R. A. Beall

This paper summarizes the development of a furnace for producing titanium castings. The general problem is outlined and chronological details are given on the construction and operation of four different casting furnaces, all utilizing consumable-electrode arc heating and water-cooled copper crucibles. Of the two methods of pouring, the tilt-pour technique has been more satisfactory than bottom tapping. Mold design, electrode fabrication, and deep-pool production are discussed. INTRODUCTION In the early summer of 1953 the Bureau of Mines was contacted by the Department of the Army through Watertown Arsenal to explore the possibility of conducting research on casting titanium metal. The objective of the program was "to develop a technique for producing formed castings of titanium metal not less than 40 pounds in weight and without introduction of deleterious contamination."

Jan 1, 1956

By Richard Stayner

Suspended seats perform two functions: Reduce effect of occasional large bumps; Reduce more continuous vibration at a lower level. The former needs high damping. The latter needs low damping. For most mobile work machines the inevitable compromise is generally better than a simple cushion seat, because that amplifies vibration at around 4 Hz which is a sensitive frequency for human vertical WBV. Why have standard tests for seat suspensions? • Seat suspensions are non-linear so any measure of performance depends on operating conditions. For comparison these need to be defined. • Seat manufacturers need benchmarks for product development; • Machine makers choose dynamic characteristics appropriate to their products; • Occupational health specialists wish to control operator exposure to Standard tests should be representative, repeatable and reproducible. These requirements are reviewed in relation to the history of seat test standards and the current position. Current position and history The current position is that we have standard tests for seats for agricultural tractors, earthmoving machinery, industrial (fork-lift) trucks. These tests comprise measurement of vibration transmission and of the rate of damping. Current standards developed as the technology developed, starting around 1960: 1. Test on machine driven over standard surface1. 2. Test on shaker reproducing standard surface. 3. Shaker input replaced by representative spectrum2. 4. Human subject replaced by dynamic dummy. (Not yet settled). Are standard tests representative? The development process has gradually moved seat tests further from reality. 4 hr samples of work exposure suggest that seats do not on average provide large reductions of vertical WBV3. For specific magnitudes of vibration they can work well. For low vibration, performance is reduced by friction and for severe vibration by length of travel. Recent work has led to a new test to quantify how a suspension controls over-travel 9.

Jan 6, 2006

By R. A. Busch, R. R. Backer, R. W. McKibbin

The Bureau of Mines conducted laboratory tests to determine the slur- ry transport and deposition properties of coal waste. A 188.5-ft pipe test loop was constructed with instruments to measure density, flow, and power and discharge, suction, and differential pressures. A 20-ton sample of Western coal waste was crushed and screened to 100 pct minus 1/2 in. Eight loop tests using this graded waste were run at slurry densities ranging from 1.15 (25 wt-pct solids) to 1.46 (60 wt-pct sol- ids). The resultant friction-pressure gradients ranged from 0.06 to 0.24 ft of water per foot of 4-in standard steel pipe. Particle-size degradation was significant. In a typical loop test lasting 25 min, the minus 200-mesh fraction increased from 19 pct to 34 pct. Deposi- tion tests showed that without the use of a flocculant, the slurries would not dewater when left to stand for 1 week. With flocculant, ad- ditional water was released; however, the settled slurries remained thixotropic. Further testing is necessary to determine their suitabil- ity for use as backfill material in active mines.

Jan 1, 1965

By W. Beckering

IN CHARACTERIZING tars obtained by the low-temperature carbonization or North Dakota lignite, infrared spectra have been an invaluable aid in both qualitative and quantitative examination. Quite early it became evident in the tar-research program of the Bureau of Mines, U.S. Department of the Interior, that the small number of published spectra available for hydroxy aromatics would be inadequate for comparative purposes when dealing with the wide range of compounds present in coal tar; therefore, compiling a catalog of spectra was initiated as a continuing part of the tar program. As these spectra should be valuable to other investigators in this and related fields, they are being presented in this report. This group or spectra (figs. 1-98) represent 97 compounds, largely phenolic materials. The major problem of this project has been the availability of materials for examination. Samples have been obtained from commercial and private laboratories or synthesized at the Bureau of Mines Lignite Experiment Station, Grand Forks, N. Dak.

Jan 1, 1959

By Martin H. Stanczyk

Bench scale, laboratory batch attrition grinding tests were made of a coarse commercial kaolin in a stainless steel, 5-inch-diameter attrition grinding machine to study the effect of a number of basic operating variables on particle size reduction and electric energy consumption. The results of the investigation showed that the more important operating variables influencing the efficiency of kaolin comminution and energy consumption requirements were type, size, and shape of grinding media, grinding media to clay weight ratio, peripheral rotor speed, clay slip pulp density, degree of pulp dispersion, and the angular arrangement of the rotor and stator bars. The tests also indicated that variables having less influence on grinding efficiency and energy consumption were pulp temperature, design of rotor cage, rotor clearance, rotor-stator bar interval, addition agents, pulp level, degree of pulp aeration, and chamber liners. The research showed that grinding media had the greatest influence on abrasion of machine parts and that spherical-shaped grinding media were superior to sharp angular or long bladed media with respect to media degradation, machine abrasion as well as grinding efficiency.

Jan 1, 1968