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By Oleg Terichow

The Bureau of Mines studied the penetration of a slender cylindrical tube into a sand bed, simulating seafloor material under the application of a static load. The factorial experimental design was based on three factors: tube diameter, geometry of penetrating bit, and seawater saturation of sand, all of which were found to be significant in influencing the depth of penetration. The geometry of the penetrating bit, or shoe, is of major significance in the mechanics of penetration and should be considered the most important factor for additional study. Linear regression analyses of the load-penetration data show that the relationship is linear.

Jan 1, 1970

By Thomas M. Barczak

The Bureau of Mines is conducting research to optimize the capability of mine roof supports so that the selection and design of these supportsare compatible with the conditions in which they are to be employed. This report describes a study that investigates three parameters influencing the load-carrying capability of wood crib supports: height, configuration, and horizontal displacement. Four crib heights, four parallelogram configurations, and three ratlos of horizontal-to-vertical displacements were tested on full-scale wood crib supports in a mine roof simulator. Test results indicated a reduction in load-carrying capability for increases in crib height. Increasing the contact area by changing the intersecting angle between crib blocks to form parallelogram configurations provided a slight increase in load-carrying capability for the first 10 to 12 in of vertical convergence, after which the cribs became more unstable, resulting in significantly less load-carrying capability. Horizontal displacements did not appreciably affect the load-carrying capability of wood crib supports for the range of vertical displacements (less than 10 in) likely to be encountered underground. This report documents these tests and postulates some explanations of failure mechanics for the observed behavior.

Jan 1, 1988

By L. J. E. Hofer

The Bureau of Mines determined rates of adsorption and desorption of methane as a function of particle size and temperature, using coals from the Pocahontas No.3 seam (lvb) from the Bishop mine of western Virginia, and the Pittsburgh seam (hvab) from the Pursglove No. 15 mine of northern West Virginia. For a given coal sample and temperature, the rate curves for adsorption and desorption are essentially the same when expressed on a fractional approach to equilibrium basis. The rates of adsorption and desorption increased eightfold as the particle size was decreased from 6-8 to 270-325 mesh per inch. The adsorption process appears to be diffusion controlled. Rate of sorption processes increased with increasing temperature; however, the amount adsorbed at equilibrium decreased.

Jan 1, 1966

By G. W. Jones, R. E. Kennedy

A simple , quick, and relatively accurate device is needed for determining the presence of very small concentrations of organic halide gases in various atmospheres . Such a device would enable safety engineers , health officials , and others to discover quickly the presence of these gases in a suspected atmosphere and thus be able to apply protective measures promptly. This detector should prove useful in detecting leakage of halide gases from refrigerating and air - conditioning systems and in determining the presence of halide solvents in the atmosphere of dry - cleaning and degreasing establishments where organic halide solvents are used . Virtually all poison war gases are halide compounds . Because of the high toxicity of these gases , even in very low concentrations , a detector having the proper sensitivity should be useful in civilian defense for determining when atmospheres are relatively free of poison gases .

Apr 1, 1943

By Phillip W. Holland

The U.S. Bureau of Mines has developed a mass spectrometer method for determining helium in the parts-per-million to 10% range to an accuracy of ± 1%. The method employs a mass spectrometer, an inlet system utilizing a chromatographic gas-sampling valve, and an activated coconut charcoal trap cooled with liquid nitrogen. Gravimetrically prepared standards of helium in nitrogen were used to demonstrate the linearity of the method over the concentration range of 10 ppm to 10.66% helium.

Jan 1, 2010

By F. P. Haver

The Bureau of Mines developed a process to extract about 90 percent of the sulfur from molybdenite flotation concentrate by compacting the concentrate with one-quarter of its weight of aluminum powder, heating it at 800° C for 30 minutes, and then allowing the product to react with water. This thermite reduction yields an impure molybdenum alloy plus aluminum sulfide. The latter readily hydrolyzes, to yield pure hydrogen sulfide which can be converted to elemental sulfur by the Claus process. At least 95 percent of the molybdenum can be subsequently recovered as 99.95-percent-pure molybdic oxide.

Jan 1, 1968

By M. Kanda, W. D. Bensema, J. W. Adams

Two different techniques were used to make measurements of the absolute value of electromagnetic noise in an operating coal mine, Itmann No. 3 Mine, located near Mullens, West Virginia. The electromagnetic environment created by 250-volt-dc and 550- and 950-volt-ac machinery in two longwall panels was measured and is reported. One technique measures noise over the entire electromagnetic spectrum of interest for brief time periods. It is recorded using broadband analog magnetic tape, and the noise data is later transformed to give spectral plots. The other technique records noise amplitudes at several discrete frequencies for a sufficient amount of time to provide amplitude probability distributions. The specific, measured results are given in a number of spectral plots and amplitude probability distribution plots.

Jan 6, 1974

The Bureau of Mines evaluated short-delay coal mine detonators manu-factured by three domestic companies for electrostatic sensitivity, strength, and no-fire current level. Electrostatic sensitivity was studied in pin-to-pin and pin-to-case modes employing lO-kV potential. Strength of detonation was measured in the Bureau's underwater test fa-cility. No-fire current was measured using a constant-current power supply unit. Test procedures and experimental data are included.

Jan 1, 1985

By Donna L. Anderson

This U.S. Bureau of Mines report discusses the status of a laser-based guidance system to provide position and heading feedback and closed-loop control of tramming maneuvers for a continuous mining machine. The system has been developed and tested at the Bureau, and is now being prepared for underground experiments. The system hardware includes laser scanners, a sensor communication network, and host computer hardware. The system software includes a position and heading computation module and a tram control module. The description of the software includes discussions of laser data acquisition, error compensation methods, position and heading determination, safety checking for continuous miner tramming, and closed-loop tram control. The accuracy of the laser scanner's data, the reliability of the lasers in a dusty environment, and the system's accuracy on tracking the position and heading of the continuous mining machine are shown in the results of experiments performed at the Bureau. Conclusions are stated based on these experimental results, and further work to improve the system performance and prepare for underground testing is discussed.

Jan 1, 1990

By Je M. Oh

The Bureau of Mines is conducting research to determine the high temperature oxidation resistance of substitute stainless steels (SS) containing two less strategic elements, Al and Si, instead of Cr. Chromium is considered to be a critical and strategic metal. Although the Cr content was reduced to 8 wt pct, the alloys showed better oxidation resistance than did 304 SS containing 18 wt pct Cr. Specifically, the alloys that contained Fe-8Cr-16Ni with combinations of Al and Si showed excellent oxidation resistance even at temperatures up to 1,000° C. In this study, the effects of the alloying elements on oxidation kinetics and morphology of oxides were investigated using a Cahn Rg electrobalance, scanning electron microscopy, an energy-dispersive X-ray analyzer, X-ray diffraction, and an electron microprobe. Aluminum and silicon additions in combinatin were more effective in providing oxidation resistance than either element was alone.

Jan 1, 1986

By W. Wan, R. V. Ramani, J. M. Mutmansky

"Diesel particulate matter (DPM) emitted from diesel engines is currently considered to be a health problem in underground mines. As a result, attempts have been made to control DPM both by reducing emission rates and by managing the DPM that gets into the mine atmosphere. This paper presents a method for modeling the generation, transfer, and distribution of DPM in coal mining sections through the use of a convection-based computer model so that controls for emitted DPM can be evaluated. A variety of ventilation strategies and diesel deployment schemes for room-and-pillar development sections were simulated to compare their effects on average DPM concentrations at several fixed and mobile personnel locations in the section. Input data for the model was gathered from actual diesel development sections and derived from experimental study results provided by other researchers. Analyzed using the model were ventilation schemes using vent tubing and brattice, exhaust location strategies on the vehicles, and the direction of ventilation at the feeder-breaker location. A summary of results from this study is presented.With diesel equipment holding an important place in underground coal mining and growing in use over time, it is important to develop and improve controls of the exhaust emissions, especially diesel particulate matter (DPM), to further reduce potential health hazards. The proper design and maintenance of diesel engines and on¬board control procedures are paramount requirements for controlling DPM successfully. There is also, however, a significant reduction potential in terms of personal exposure that can be realized by managing the DPM that gets into the airstream. Strategic design of the mining, ventilation, and equipment implementation systems remain essential for efficiently reducing the DPM concentrations.Modeling the effect of diesel exhaust contaminants upon the mine atmospheric quality will permit improved health and safety design of the overall mining and ventilation systems. Numerous studies have been performed to model the distribution/transport of gaseous and particulate emissions in the underground mine atmosphere and some very sophisticated convection/diffusion models have been developed (Skobunov, 1974; Thakur, 1974; Stefanko and Ramani, 1975; Wala, 1980; Bandopadhyay and Ramani, 1983). Most of these models were developed for a single airway or based on the assumption that the ventilation network of a mining section can be approximately represented by a single intake and a single return. The complexity of most models of the convection/diffusion type and the mobility aspect of diesel haulage units made a detailed emissions model very difficult to develop.The current model is an attempt to fill the need for a more generic tool applicable to mining sections employing multiple mobile diesel units by simplifying the convection-diffusion model to a convection-only model. The simplification is based on the fact that the diffusion coefficient will affect only the transient environmental contaminant concentrations with little or no affect on the time-weighted-average concentrations over a relatively long period such as a working shift (Lee et al., 1994). In view of the difficulties involved in mathematical modeling, the approach here is developing and using a computer simulation model. A PC-based FORTRAN 77 simulation model for the analysis of mining systems with multiple diesel sources and any ventilation network configuration was developed to study the distribution/transport of DPM in mine airways, evaluate methods of reducing DPM concentrations, and explore modifications to existing mining practice."

Dec 1, 1996

By LB. Berger

"INTRODUCTION The use of gasoline engines as the motive power for lift trucks, tractors, and other types of mobile equipment operated in enclosed spaces, such as industrial plants and warehouses, may create a hazard because of the carbon monoxide present in the exhaust gases of the engines; gasoline-powered equipment should not be used in mines or tunnels. Because the equipment is mobile, local ventilation usually is impracticable, and general ventilation of the spaces is nec-essary to dilute and remove the carbon monoxide. To estimate the rate of ventilation required in such situations, information is necessary on the concentration of carbon monoxide in the exhaust gas and the rate at which exhaust gas is produced under given operating conditions. The purpose of this paper is to present data that may be used in making estimates of ventilation requirements.COMPOSITION OF GASOLINE-ENGINE EXHAUST GASThe exhaust gas of a gasoline engine consists mainly of carbon dioxide, carbon monoxide, hydrogen, oxygen, and unburned hydrocarbons (usually reported as methane), together with the nitrogen present as a residue from the air sup-plied for combustion. 3/ The exhaust also contains water vapor resulting from combustion of the hydrogen of the fuel. The water-vapor content is not included in exhaust-gas analyses calculated on a ""dry"" basis and is not involved in the estimation of ventilation requirements."

Jun 1, 1947

By D. Harrington

The occurrence of dusts in underground workings creates many difficult and, in some instances, contradictory and conflicting problems for workers, operators, and all others interested in health and safety in mining and tunneling. Moreover, there are many misconceptions both as to the actual effect of most dusts which may be encountered in underground work and as to remedial or alleviating measures. Although the harmfulness of mine dusts to health of miners has been mentioned by man; writers in ancient times, much of our really authentic knowledge of the effect of underground dusts upon health or safety in both coal and metal mines has been pained during the past 30 or 35 years. There has been, however, a considerable amount of generalizing from some local condition or occurrence or theory rather than arriving at conclusions after extended studies and observations made not only in mines and tunnels but also in town, camps, and plants, and comprising date on as many different mining and tunneling localities, conditions, etc., as could be secured with reasonable expenditure of time or money. This paper dives sortie observations based on the writer's 30 odd years of experience in and around both coal and metal mines, including approximately 20 years? close study of dust disease with detailed surveys and reports on dust occurrence and effects in considerably more than 100 mines in probably 20 States of the Union. The observatio are those of an engineer and in many respects conflict the with "going" ideas of doctors, pathologists, and others who have written on dust disease. Were the word dust is used in this p: per in connection with respiratory disease, it refers to solid particles which float or can float in the air breathed by workers. Although these particles are usually dry, they may be wet; in general, their dimensions are so small as to be invisible to the nailed eye. Dusts in coal mines which may be involved in the initiation or extension of explosions, are generally thought to be those which are smaller than 20-mesh in size but chiefly finer than 20-mesh; coal-mine dusts which are harmful to health of workers have essentially the same general physical characteristics as other dusts, but usually consist of smaller particles.

Jan 1, 1936

By Charles Vaught

The U.S. Bureau of Mines evaluated the self-contained self-rescuer (SCSR) donning proficiency of 243 miners. These workers were from eight underground coal mines in the eastern United States. The objectives of the study were (1) to gather information on skill levels, since all miners in the study had prior instruction and opportunity to practice donning the apparatus, and (2) to summarize a quality control procedure useful in conducting periodic evaluations of donning proficiency. The sampling procedure used proved to be both reasonable and efficient in gathering information on training effectiveness. It also provided a good statistical base for making informed site-specific decisions regarding SCSR training needs. Results from the observed samples at each of the eight mines indicate a wide variability across sites. The rate at which miners failed to isolate their lungs varied from 3.3 to 40.0 pet. Concomitantly, proficiency rates (miners either performing adequately or demonstrating a perfect 3 + 3 sequence) ranged from 13.3 to 63.3 pet.

Jan 1, 2010

By Lisa Steiner, Robin Burgess-Limerick

In 2004, there were 646 underground coal mines in the USA employing 37,445 miners. These mines reported 3556 injuries to MSHA that year - 17% were associated with bolting machines (593 injuries), 8% with continuous miners (283 injuries), and 4% each with Scoop/LHD (1 51 injuries), shuttle cars (134 injuries), and personnel transport (145 injuries). The use of the frequency of reported injuries for the prioritization of risk control strategies has limitations because of the tendency to underestimate the importance of relatively rare but high-consequence events. Injury reports also underestimate the contribution of risk factors such as whole body vibration, which have a long-term cumulative contribution to an elevated risk of injury. However, taking these limitations into consideration, the results of the injury narrative analysis suggest the following hazards as the highest priority for elimination or control: • rock falling from supported roof • inadvertent or incorrect operation of bolting controls • handling continuous miner cable • collisions while driving LHD/Scoop, shuttle cars and personnel transport • rough road while driving or traveling in LHD/Scoop, SC & PT

By J. L. Ambs

The U.S. Bureau of Mines (USBM) Diesel Research Program emphasizes the development and evaluation of emission control devices to reduce exposure of miners to diesel exhaust pollutants. Studies by the USBM have shown that diesel exhaust aerosol (DEA) contributes a substantial portion of the respirable aerosol in underground coal mines using diesel equipment not equipped with emission controls. The USBM and the Donaldson Co., Inc., Minneapolis, MN, have developed a low-temperature, disposable diesel exhaust filter (DDEF) for use on permissible diesel haulage vehicles equipped with waterbath exhaust conditioners. These were evaluated in three underground, mines, to determine their effectiveness in reducing DEA concentrations. The DDEF reduced DEA concentrations from 70 to 90 pct at these mines. The usable life of the filter ranged from 10 to 32 h, depending on factors that affect DEA output, such 'as mine altitude, engine type, and duty-cycle. Cost per filter is approximately $40.

Jan 1, 2010

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Jan 1, 2012

By J. M. Mutmansky

"The objective of this study was to produce coal dusts for laboratory research that are similar to mine airborne dusts in chemical, mineral, and physical characteristics. In this investigation, dusts produced in laboratory comminution equipment were compared with continuous miner- generated dust for similarity in physical characteristics. Mining-generated dust (MGD) and bulk coal samples were first collected from an underground mining operation. The bulk samples were then processed in the laboratory for size reduction in various comminution devices. These laboratory- generated dust (LGD) samples were subjected to size and microscopic analyses. Physical properties of the dust particles were studied on a scanning electron microscope (SEM ). A numerical shape coordinate system (SCS) was also developed and applied to 300 particles from each sample. Statistical analysis was then performed on the collected data and characteristics of the MGD and LGD samples were compared. IntroductionIn many biomedical studies, researchers routinely introduce a dust mass into an experimental environment to assess the response of a biological entity, usually lung macrophages in vitro or a live laboratory animal, to the dust mass. To provide data of maximum usefulness, it is highly desirable to use dust with characteristics of actual mine airborne dust. The primary objective of this research was to produce dusts in the laboratory similar in chemical, mineralogical, and physical characteristics to mine airborne dusts. This paper outlines the evaluation of the physical characteristics of the lab-generated dusts.Particle shape analysis is perhaps the least-developed area in mineral-related particle science and technology. There are still no standard methods or instruments to scientifically quantify particle shapes. To date, many attempts have been made to characterize particle shapes. These procedures can be roughly classified into three categories:"

Dec 1, 1995

By D. E. Fogelson

In a factorial experiment, blasting caps were detonated in three sizes of shotholes in mortar with three types of stemming--dry sand, wet sand, and hydrostone. Free-surface displacement pulses were recorded with a capacitive-displacement gage at a distance of 15 inches. The effects of decoupling and the type of stemming on the amplitude and the duration of the displacement pulse were determined. Both the amplitude and the duration of the displacement pulse were significantly decreased by increasing the decoupling, but they were little affected by the type of stemming.

Jan 1, 1965

By R. E. Lindstrom

Effective separation of rare-earth mixtures is obtained using hydrogen as a retaining ion at 200° F with ethylenediaminetetraacetic acid (EDTA) eluant. Results obtained in Bureau of Mines bench-scale apparatus and large columns with hydrogen as a retaining ion closely parallel those obtained with copper as a retaining ion. The use of hydrogen as a retaining ion permits EDTA and water, collected before rare-earth breakthrough, to be recovered in a form that allows the material to be recycled without extensive processing. With the exception of yttrium and dysprosium, separation of rare-earth mixtures is improved and throughput is increased by elevated temperatures. Separation with 1,2-diaminocyclohexanetetraacetic acid (DCTA) eluant increases markedly on increasing temperature from ambient to 250° F; however, on the basis of separation efficiency, DCTA does not compare favorably with EDTA.

Jan 1, 1962