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By R. V. Ramani, R. Stefanko, G. W. Luxbacher

Comprehensive ventilation surveys are made to review the adequacy of the mine system with regard to both statutory requirements and/or company policy, to evaluate improvements to the current ventilation system and to plan for £stun expansion. If computer simulation is to be used for these purposes, accurate quantity and pressure measurements become an absolute necessity since the validity of the computer generated output is heavily dependent on the accuracy of the input data. Consequently ventilation surveys that are run to generate input data for computer simu¬lation must use the best data collection procedures to guarantee as accurate results as are possible. These requirements have led to modifications in procedures that are used for routine ventilation surveying. McElroy and Kingery (1957) have recommended that pressures be measured independent of quantities since minor changes in mine conditions have a greater effect on absolute pressure measurements than on quantity measure¬ments. They estimate that, for large mines, a pressure survey may take only 1 to 3 days while the corresponding quantity survey would require 1 to 3 weeks. Although this procedure would undoubtedly lead to more ac¬curate pressure measurements, its use for the development of computer input data is not recommended for the following reasons. Atkinson's equation, H = RQ2, is used in computer oriented analysis to develop the airway resistance, R, based on quantity and pressure loss measure¬ments. It can easily be seen that since R a 1/Q2 and R a H, the effect of errors in quantity measurement is, in fact, more significant than those in pressure measurement. If the quantity and pressure measure¬ments are made at different times another problem results. Minor changes in quantity that may occur in the time between the pressure and quantity

Jan 1, 1977

By Dean H. Ambrose

This paper presents an approach for representing and analyzing random motions and hazardous events in a simulated three-dimensional workplace, providing designers and analysts with a new technique for evaluating operator-machine interaction hazards in virtual environments. Technical data in this paper is based upon a project striving to reduce workers' risks from being hit by underground mining machinery in a confined space. The project's methodology includes human factors design considerations, ergonomic modeling and simulation tools, laboratory validation, and collaboration with a mining equipment manufacturer. Hazardous conditions can be analyzed in virtual environments using collision detection. By simulating an operator's random behavior and machine's appendage velocity, researchers can accurately identify hazards, and use that information to form safe design parameters for mining equipment. Analysts must be discerning with the model and not read more from the databases than what the simulation model was designed to deliver. Simulations provided an interesting approach to data gathering in that there was no need for live subjects and logistics - test sites and costs associated with experiments-became insignificant. Collisions versus speed, operators' size, and risk behaviors proved the versatility found in the data obtained from the model. Preliminary results show that response time significantly affects the number of collisions experienced by the virtual subject. Also simulation data suggests that more mishaps occur with hand-on-boom-arm risk behavior.

By James P. Rider, Jeanne A. Zimmer, Andrew B. Cecala, Robert J. Timko, Earle H. Andrews

Many different types of structures and materials have been used to build mineral processing facilities over the past few decades. Although the structure type and building material were not viewed as significant factors affecting the health of employees in these facilities when they were built, the National Institute for Occupational Safety and Health performed an evaluation to determine to what extent building types could impact respirable dust and noise levels. This report discusses the evaluation of three different types of product sizing silica sand structures: a masonry design, a steel-sided design, and an open structure design. The data obtained in this study indicate that the open structure design (no walls) was superior from both a dust and noise (health) standpoint compared to the other two structures. The open structure design should also be beneficial from a cost standpoint because of lower material and construction costs. Companies and design engineers should consider this open design when building new mineral processing facilities in climates where it could be applicable. Some companies may also want to consider modifying existing structures with a more open design to further reduce dust and noise levels. As the trend continues in lowering allowable dust levels for federal health standards in the U.S. mining industry, the open structure design may be an approach for some companies to consider for their operations.

Jan 11, 2006

By Larry G. Stolarczyk

1.0 FRAMEWORK FOR COMPARISON This document describes the decision factors that bear on the selection of the modulation process for the wireless underground medium frequency (MF) communication system. The selected modulation process must satisfy the Bureau of Mines stated objective of improving general communications within an underground mine. The improvement being sought includes the development of a wireless communication technology of measurable benefit to both mine safety and mine productivity. The improvement will allow wireless communications paths to exist between roving miners. The wireless communication paths will also be made compatible with the existing underground telephone system to extend paging and voice communication throughout the underground mine. The new wireless equipment will include man-pack, vehicular, repeater, and base station transceivers. Repeaters and base stations will feature coupling networks for interfacing with the existing telephone circuits. Frequency modulation (FM) and single sideband (SSB) modulation processes are analyzed in view of the special conditions associated with underground mining. Of primary importance is the tremendous electrical noise generated in an operating mine that could adversely affect communications quality. High noise coupled with high attenuation rate of near field signals forces the communication system to be inherently short range. Fortunately, near field signals can propagate over great distances on underground wires and cables. The framework for comparison is generated by presenting all factors that

By Mark I. Copeland

The formation of A1203 dispersoids 0,14 and less in size in dilute iron-aluminum alloys by internal oxidation in wet hydrogen and dispersion strengthening of iron by application of the technique to iron powder were found to be feasible by the Bureau of Mines. In flowing H2-1.5 H20 gas, A1203 dispersoids 0.1w and less in size formed (at 650° to 750° C) in Fe-l and 2 Al sheet material but not in Fe-3 or 4 Al alloys. With higher temperatures and/or higher H2O/H2 volume-ratio gases, A1203 and FeA1204 dispersoids >0.14 in size formed in all the sheet materials- Minus 100-mesh Fe 2 Al powders were internally oxidized under conditions that promoted formation of fine A1203 particles in sheet material, and then the oxidized powders were hydrogen reduced, sintered, extruded, and evaluated. During internal oxidation, fine A1203 dispersoids formed within the powder grains, and coarse FeA1204 particles formed on the powder surfaces and grain boundaries. The FeA1204 content was essentially eliminated during sintering by reacting with the unoxidized aluminum that remained in the center of the larger internally oxidized powders. The tensile strength at 800° C depended upon the aluminum-oxygen weight ratio of these elements in the extrusions and reached a maximum of 17,000 psi. The stress-rupture strengths at 800° C of the better alloys were comparable with those of type 310 stainless steel.

Jan 1, 1972

By L. Cheng, M. S. Seehra, P. S. Raghoottama

The four major IR bands of a-quartz at 1080, 797, 693 and 488 cm-1 are studied at room temperature by FTIR-Photoacoustic Spectroscopy. Using Rosencwaig-Gersho theory, equations for the PAS signal q for the thermally thin and thermally thick cases are derived and it is shown how thin to thick transition occurs and leads to saturation as the sample mass is increased. For sample mass < 2 mg, q is proportional to sample mass thus defining the region for quantitative analysis. The dependence of q on the chopping frequency f is found to vary as q f-n with n ? 0.9 for quartz, in good agreement with the RG theory.

Jan 1, 1989

By L. W. Higley

Particulates generated in electric furnace (EF) steelmaking constitute approximately 1 to 2 pct of the charge. This flue dust is a rich source of zinc (values are substantially higher than in ore), but although there are several processes for recovering the metal, none are considered economic in the United States. This report reviews extraction technology and presents results of Bureau of Mines reduction-volatilization tests on pelletized EF dusts which achieved high recoveries of zinc. The data are sufficiently encouraging to warrant consideration of EF dusts as raw material for primary zinc smelters.

Jan 1, 1977

Engineering controls for overburden drilling include dry dust collection systems, wet dust suppression systems, and enclosed cabs [Zimmer and Lueck 1986; Volkwein et al. 1979]. Proper maintenance of the dust suppression system is critically important for drills using dry dust suppression methods. Failure to rigorously maintain these systems will result in inadequate dust control. Acute silicosis has been reported in miners operating equipment that relies on dry dust suppression [NOSH 1992].

Jan 1, 1997

By F. D. Wang

The Bureau of Mines has developed a computer program for evaluating pit slope stability by the finite element stress analysis and limiting equilibrium method. The program includes the finite element method of stress analysis using triangular elements, finite-element model mesh generation, plotting of the model mesh and stress contours, calculation of a factor of safety along a circular or a plane failure surface, and location of a critical circular failure surface. Instructions for preparation of input data, an example problem, and the program listing are presented.

Jan 1, 1972

By Kenneth C. Stewart

Eight brands (three samples of each kind) of commercially available audio-dosimeters were performance-tested. Each unit was placed in an anechoic chamber and subjected to various acoustic signals to measure its A-weighting response and overall integration accuracy. All units met the A-weighting tolerance for type II sould level meters, and six brands were within the Bureau I s overall accuracy requirements of ±2 dbA referred to input.

Jan 1, 1974

By J. R. Welty

High-temperature thermodynamic data have, in recent years, become increasingly important for the extractive metallurgist. The extraction of metals from their ores previously was based on trial and error methods, involving hours of testing and often costly equipment fabrication. Using thermodynamic data it is frequently possible to predict the feasibility of a proposed metallurgical process as well as the optimum operating conditions for the process with reasonable accuracy. Such predictions can save consider-able tim~ and expense. Widespread use of thermodynamic analyses has been handicapped by lack of dependable experimental data. Investigators, notably K. K. Kelley (4)4. have devoted many years to determining and compiling such data. These investigators, although prolific in their production of thermodynamic values, have been unable to meet all the needs of industry and other branches of science. This becomes obvious when one considers the aeronautical and nuclear fields, in which previously unimportant, therefore uninvestigated, substances have become of prime importance.

Jan 1, 1962

By Ronald S. Conti

This is the fourth and final article in a series that discusses underground fire-fighting preparedness. As with the previous three articles, it is based on interviews with 214 miners at 7 underground coal mines (referred to as Mines ?A? through ?G?) conducted by researchers of the National Institute for Occupational Safety and Health?s(NIOSH) Pittsburgh Research Center[Vaught et al. 1996]. The first article presented an overview of the study conducted by NIOSH on mine fire response preparedness and provided a general perspective on underground mine fires. The second article discussed miners? preparedness to evacuate a fire and their experience with incipient fires. The third article described miners? experiences in fighting underground mine fires and presented their perceptions of training and readiness for fire-fighting. This final article in the series offers suggestions to improve mine fire-fighting preparedness.

Jan 1, 1997

By C. B. Manula, R. L. Sanford, R. A. Rivell

PART I. DATA INPUT FOR THE OPERATING PROTOTYPE [To run the Rail Haulage Model independent of the Production Sub-system, remove the production data from card type four through the blank card following END DATA on page B18 and change the fourth data element under ADDITIONAL DATA from 1 To 0.]

Jan 1, 1974

By Marvin L. Whisman

A radiotracer technique developed by the Bureau of Mines extends to the parts-per-billion range the sensitivity for determining contributors of deposits formed in stored and thermally stressed jet fuels. The method depends upon measuring radioactivity associated with thermally induced deposits from fuels containing one labeled compound. The technique was applied to 88 test blends, representing 12 fuels and nine carbon-l4 labeled fuel constituents or fuel additives, or both. Data from results of these tests are included in this report. With this radiotracer technique, the contribution of fuel components and additives to thermally induced deposits in a variety of fuel environments was estimated before and after storage.

Jan 1, 1969

By W. E. Wallace, V. Castranova, P. Hathaway, F. H. Y. Green, E. D. Recad, V. Vallyathan, M. J. Keane

Inhaled particle contact with pulmonary surfactant in the hypophase lining pulmonary alveoli was modeled in vitro by exposing two respirable sized dusts, kaolin and silica quartz, to lecithin, a major component of pulmonary surfactant, emulsified in physiologic saline. Lecithin adsorbs to the dusts upon incubation at 37º C and suppresses their cytotoxicity as measured by pulmonary macrophage and erythrocyte assays, suggesting that pulmonary surfactant provides a defense system against prompt cell membrane lysis by inhaled dusts. Subsequent pulmonary macrophage phagocytosis and lysosomal enzyme digestion of the coated dusts was modeled in vitro by incubation with phospholipase A2 for one hour. With increasing lipase activity, silica hemolytic potential was restored to native silica levels. Kaolin was retoxified to levels far in excess of native kaolin hemolytic potential. Elution, thin layer chromatography and phosphate assay of treated dusts indicate most lecithin on silica is digested to lysolecithin and desorbed, silica retoxification being due to surface and adherent lysolecithin effects. Most lecithin on kaolin is not digested in this same time; that which is results in adherent lysolecithin which is responsible for the kaolin retoxification. Digestion with phospholipases A2 and C together produces only weakly retoxified kaolin. Results suggest that surface adsorption properties which control the adherence of prophylactic surfactant distinguish the pathogenic potentials of quartz, kaolin and mixed dust.

Jun 1, 1988

By Maria I. De Rosa

This report analyzes mobile equipment fires for all U.S. surface and underground coal and metal/nonmetal mining categories by state and 2 year time periods during 1990-1999. Risk rate values are derived, and ignition source, methods of fire detection and suppression, and other variables are examined. The data were derived from MSHA mine fire accident publications and verbal communications with mine personnel. The analyses will provide the National Institute for Occupational Safety and Health (NIOSH), the Mine Safety and Health Administration (MSHA), and the mining industry with a better understanding of the hazards associated with mobile equipment fires and will create a basis for future fire research programs.

Jan 1, 2004

By Richard H. Spencer, Warren G. Bender

Since the passage of the Coal Mine Health and Safety Act of 1969, the Bureau of Mines has made many advances in mine communications. These efforts have resulted in the following developments and demonstrations: • Surface-to-surface electromagnetic transmission of baseband voice signals through overburdens as deep as 600 feet. This transmission was achieved with equipment from the Interim Mine Rescue and Survival System Program, and demonstrated that baseband voice communications could be obtained through these overburdens in the absence of mine-generated noise; that is, when the mine power system was shut off. However, during mine operational conditions, the mine-generated noise proved to be so large that effective baseband voice communications to the desired depths could not be effected. • The development of beacon transmitters for locating trapped miners. This work was again the outgrowth of the Interim Mine Rescue and Survival System. Extensions of this work have led to reliable detection and location of trapped miners to depths of 1000 feet. The system, which makes use of a loop antenna deployed where the trapped miner is located, uses low-duty-cycle, tone-burst transmission. Portable tuned receivers and loop antennas are used on the surface to determine the location of the trapped miner. An extension of this work has led to a call-alert paging system concept, wherein a transmitter, similar to that used in the trapped miner system, is used to audibly and/or visually alert key mine personnel carrying pocket receivers that they are wanted at the nearest mine telephone. In addition, a roof-bolt paging system has been developed, wherein commercial paging and mine carrier phone equipment are used in conjunction with a long-wire "roof bolt" antenna to page individuals and relay to them short voice messages.

Jan 7, 1975

By R. V. Ramani, C. B. Manula, A. Owili-Eger

• MINE VENTILATION NETWORK PROBLEM (NATURAL SPLITTING; FIXED • QUANTITY BRANCHES; METHANE SIMULATION; NETWORK TOPOLOGY REVISION; • ABSOLUTE PRESSURE) • NFIXB = NO. OF FIXED QUANTITY BRANCHES • DD(I) = AIR QUANTITY ASSIGNED TO FIXED QUANTITY BRANCH I, IN KCFP • NFBPF = NO. OF FIXED QUANTITY BRANCHES PLUS FAN • NFBPFG = NO. OF FIXED QUANTITY BRANCHES PLUS FAN PLUS METHANE • EMISSION BRANCHES • NBWNVP = NO. OF BRANCHES WITH NATURAL.VENTILATION PRESSURE • NVP(I) = NATURAL VENTILATION PRESSURE ASSOCIATED WITH • THE I-TH BRANCH • NF = NUMBER OF FANS • NB = NUMBER OF BRANCHES • MAXIT = MAXIMUM NUMBER OF ITERATIONS • MAXJ = MAXIMUM NUMBER OF JUNCTIONS • NJ = NUMBER OF JUNCTIONS INVOLVED IN THE SOLUTION * NM = NUMBER OF MESHES • NP = NO. OF POINTS TO DESIGNATE FAN CHARACTERISTIC * Q = QUANTITY OF AIR FLOW IN KCFM • R = RESISTANCE OF AN AIRWAY • WIDTH = AIRWAY DIMENSION • LENGTH = AIRWAY DIMENSION • HEIGHT = AIRWAY DIMENSION • SUMNVP = SUMMATION OF NATURAL VENTILATION PRESSURE FOR ANY MESH • X (I) = QUANTITY OF AIR, IN KCFM, ASSOCIATED WITH THE I-TB POINT • ON A FAN CHARACTERISTIC • E = ERROR FOR CONVERGENCE • FF = FRICTION FACTOR • FX(I) = FAN PRESSURE, INS INCHES OF WATER GAGE, CORRESPONDING • • TO A QUANTITY X(I) • H = HEAD LOSS IN INCHES OF WATER GAGE • I = BRANCH NUMBER • J, J1, J2 = JUNCTION, J1 AND J2 ARE TWO NODES WHICH DEFINE A • BRANCH • KEY = NO. WHICH SIGNALS THE TYPE OF FAN CHARACTERISTIC TO BE • EXPECTED

Jan 1, 1975

By C. N. Schuette

"The production of silica and magnesia crucibles in the induction furnace was attempted and achieved in the laboratory of the Pacific Experiment Station of the United States Bureau of Mines. This work was undertaken at the request of other stations for laboratory crucibles of a certain specified wall thickness and capacity.The essential new parts of this work are the development of a technique for the high-frequency furnace production of silica crucibles of greater wall thickness than could be readily fabricated from commercial fused silica, and for heavy-walled magnesia. crucibles of great density and mechanical strength. A considerable bode of patent literature on the Production of fused silica ware in resistor-type furnaces was examined, but it furnished no significant help for the present problem. Similarly sintered magnesia refractories are often made for technical purposes, but for use at temperatures of 2000o C. or over, the material must be sintered at higher temperatures than can be attained by combustion firing, and the very great shrinkage encountered at these temperatures requires special methods. Small crucibles. of magnesia fused in the electric arc have been made by Tritton and Hansen,3 but the practical size of such containers is very limited.Many different methods of making crucibles in the induction furnace were tried before satisfactory results were obtained. The following description covers only the most satisfactory method, which produced crucibles of excellent quality in a reasonable time and with a moderate expenditure of power and materials."

Oct 1, 1929

By Graham W. Marks, RALPH MILLS, FRANK COSSEY

To determine the focal length of lenses or the performance of lens systems before mounting them permanently , it is desirable to have a device in which one or more lenses can be mounted easily and their positions relative to a light source and screen changed readily . We have designed and constructed such an optical bench and lens holder . The bench is similar to that of Houstoun5/ but has been modified , whereas the lens holder is , we believe , a new design .

Jan 1, 1948