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By Terry S. Cory

This report covers antenna design, analysis, and development work suited for use with a wireless radio communication system operating at medium frequency. The work includes the test and evaluation of prototype vehicular antennas developed during the program.

Jan 12, 1978

By C. W. Owings

"PURPOSE OF REPORTThe safety and efficacy of permissible storage—battery gathering locomotives are becoming recognized more and more in coal mines. The great mobility of this type of haulage equipment is due to the fact that no trolley wire and bonding of rails are needed; hence wherever there is track and adequate ventilation to dilute properly any dangerous gases, the storage—battery gathering locomotive may go. As coal near the outcrop or the surface is mined out, coal farther from the outcrop or deeper in the ground must be mined, and gassiness of the coal bed often increases under these conditions. The use of electrical equip¬ment capable of giving off arcs or sparks while operating near or at the coal faces constitutes a serious explosion hazard. Often, it is uneconomical or impracticable to use animal haulage, and locomotives must be employed. The operator should consider the safest and most economical unit; permissible equipment is the answer to this problem, and storage—battery locomotives are the only permissible electric haulage units.A comparison of permissible storage—battery locomotives with cable—reel locomotives of the latest enclosed ""explosion—tested"" type has been made at the Keystone No. 1 mine of the Houston Collieries Co., at Keys one, W. Va. The information and data contained in this publication were obtained by the writer during an inspection of haulage at this mine.ACKNOWLEDGMENTSThe writer is indebted to P. C. Thomas, vice president and general manager, the Koppers Coal Co., operator of the Keystone mines, who granted permission for making the study. W. A. Wilson, general superintendent, Houston Collieries Co., arranged for the investigation and for obtaining the data. C. E. Zuspan, chief electrical inspector, and J. C. Newman, division electrical inspector, accompanied the writer underground and assisted materially in obtaining information and data upon the haulage methods and performance of the locomotives. The assistance or general mine Foreman Pierman and of mine foreman White is gratefully acknowledged."

Aug 1, 1931

Develop a reliable, portable device for non-destructively testing the support integrity of a friction rock support (commonly referred to as a Split Set ). Approach The friction rock support, used to support mine roof and ribs, is a slotted tube driven into a drilled hole of smaller diameter. Upon installation, the tube is compressed radially. The amount of compression is a function of the hole diameter, the strength of the host rock, and the properties of the split set itself. A simple lightweight self-contained device was developed to determine the pull-out resistance of the friction rock supports in-situ, based on measurements of the tube's deformation. The tester measures the com-pressed internal volume of the slotted tube, which has been found to provide an estimate of the support's resistance to pull out. How It Works The tester consists of a pump and expander sections. The expander sections are made from an elastomer membrane which is stretched over two cores, each one inch in diameter and twelve inches long. The expanders are connected by a flexible coupler so that they can fit any alignment of the support.

Jan 1, 1984

By Robert W. Freedman

Vacutainers are employed by the Bureau of Mines and the Mining Enforcement and Safety Administration for sampling mine air and other atmospheres containing fixed gases, low-molecular-weight hydrocarbons, and products of combustion. Tests were conducted to study shelf life of evacuated samplers prior to sampling and also to check the stability of sampled gases prior to analysis. An unexplained phenomenon, slow accumulation of carbon monoxide in evacuated samplers, occurred after a few weeks' storage; levels were low but increased with time and could pose a problem for critical applications. Accordingly, attempts to halt CO release by additional means of treatment were made, and storage at low temperature was found to be effective.

Jan 1, 1978

By Mary F. Koehler

Interoxidic compounds, such as vanadates, have not been studied extensively in the field of thermodynamics. This is a report of three vanadates of sodium--metavanadate, pyrovanadate, and orthovanadate. Vanadates of other metals will be considered in future reports. The heats of formation at 298.15° K. of the three sodium vanadates (both from the oxides and from the elements) were derived from the results of sodium hydroxide solution calorimetry. Free energies of formation were obtained by combining heat and entropy values. The results support the conclusion that the three sodium vanadates were stable with respect to all possible decompositions in which vanadium retains its pentavalency.

Jan 1, 1960

By Foster Fraas

A separator for minerals of low magnetic susceptibility and fine particle size in a water suspension is described. A ring-shaped matrix of ferromagnetic fragments rotating so as to pass successively through magnetic-field and field-free regions provides for the separation. Application is illustrated in the separation of hematite and ilmenite from quartz.

Jan 1, 1966

By E. G. King

Existing thermodynamic data for compounds of the rare-earth metals are few in number and often inaccurate because, in the past, it was difficult to obtain samples that were pure enough and reasonable in cost--a situation that is rapidly improving. This paper reports the results of low-temperature heat-capacity and high-temperature heat-content measurements for cerous fluoride (CeF3) and supplies the first such published data for a rare-earth fluoride. The low-temperature heat-capacity data cover the temperature range 51°-298° K. and serve to evaluate the entropy at 298.15° K. The high-temperature heat-content data cover the temperature range 298°-1,799° K., including the temperature and heat of fusion. The results are assembled for ready use in thermodynamic calculations. Cerous fluoride is one of the important intermediate compounds in the production of cerium metal.

Jan 1, 1959

By Gwendolyn D. Hood

The U.S. Bureau of Mines developed a dewatering technique for treating wastewater that was tested on waste slurry from a commercial tile company in Alabama. Raw wastewater samples were pretreated with 10 Ib calcium chloride and 10 lb Wyoming bentonite per 1,000 gal of slurry. After pretreatment, polyethylene oxide (PEO) at dosages varying from 0.05 to 0.20 lb per 1,000 gal was mixed with the waste slurry, forming strong, tough floes that were separated from the clarified water using a trammel. The flocculated slurry was dewatered to a consistency that could be handled for subsequent disposal in a landfill. The clarified water quality was equivalent to that of the company's present treatment system.

Jan 1, 2010

By David R. Flinn

This Bureau of Mines report describes methods to electrodeposit erosion-resistant titanium diboride coatings from molten alkali metal borate baths at 900° C. These coatings have been shown to be highly resistant to material loss during impingement with high-velocity alumina and silicon carbide powders, and they show promise as protective coatings to reduce metal loss in erosive chemical environments, such as coal gasification systems. The most erosion-resistant coatings were prepared on nickel, Inconel, and molybdenum from an electrolyte containing LiBO2, NaBO2, Na2Ti03, and TiO2. The best coatings were deposited at current densities of [~]20 ma/cm2, using titanium or titanium diboride anodes. Erosion-resistant coatings were shown to exhibit (1) a high degree of crystallographic orientation along the (100) or (110) planes, (2) a chromium impurity level of less than 3 pct, and (3) a uniform, smooth, consolidated surface appearance when viewed under a microscope or by scanning electron microscopy. Optical spectroscopic studies of the molten electrolyte suggest that the lower valent (+3) titanium ion predominates in the baths.

Jan 1, 1979

By R. W. Van Dolah

An important function of stemming used to confine explosives in shot holes in underground coal mines is to minimize the chance of ignition of firedamp or coal dust by the detonation products. Until 1952, the Bureau of Mines approved only the use of fireclay or similar incombustible material for stemming permissible explosives. At least 2 feet of stemming were required except in holes less than 4 feet deep; in such short holes the stemming was required to be half the depth of the hole. Over the years, several special stemming devices have been proposed in the United States as substitutes for fireclay. Many economic and safety advantages were claimed for these devices, but only one approved device has been marketed in this country. Bureau requirements for stemming explosives in coal mines were modified at that time to permit the approved stemming device to be used as a substitute for the required fireclay.

Jan 1, 1961

By S. P. Sandoval

Several researchers have shown that the surface of chalcopyrite becomes hydrophobic under oxidizing conditions. Because dissolution of copper from chalcopyrite in dump leaching occurs under oxidizing conditions, the U.S. Bureau of Mines studied the effect of surfactants on chalcopyrite leaching under dump chemical conditions. Surfactants were selected for study because they can lower interfacial tension. The tests were conducted in shaking water baths using 250-mL Erlenmeyer flasks in statistical experimental design formats. The addition of nonionic surfactants increased copper extraction in the fernc sulfate leaching of chalcopyrite when sufficient Fe3+ was present. A positive interaction between Fe3l+ concentration and surfactant concentration was demonstrated. Copper concentration in the leachhing solutions was increased by as much as 100 pct at 25° and 50° C by adding nonionic surfactants. ionic surfactants decreased leaching. The structure of the nonionic surfactants and their hydrophile-lipophile balance (HLB) influenced surfactant performance. The branched hydrophile of an ethoxypolyol was beneficial to surfactant performance. The ethoxypolyol was the superior surfactant at 25° C, but became unstable at 50° C. Four surfactants, an ethoxyalchohol and three block copolymers, performed best at 50° C.

Jan 1, 1990

By B. W. Gandrud

In 1927 Coghill5 showed that there is considerable liberation of the iron oxide mineral from gangue when the Alabama red iron ores are ground to a size suitable for classification and tabling, but that there is not sufficient to make possible a high extraction and a high grade of concentrate. Coghill states: High extraction and high grade of concentrate cannot be obtained without grinding to a size comparable with flotation or cyanide practice. If grade of concentrate be sacrificed the grinding need not be so severe.

Jan 1, 1934

By K. C. Dean

Time and motion studies were made by the Federal Bureau of Mines on the hand and machine dismantling of scrapped auto starter motors, generators, and alternators for recovery of copper, aluminum, and iron. The studies showed that an individual with power handtools and convenient access to a hydraulic press, power bandsaw, acetylene torch, and power lathe could, in an 8-hour day, disassemble about 100 starters, or 150 generators, or 30 alternators. The scrap copper yield would be 280, 390, and 45 pounds, respectively, and the iron yield would be about seven times the copper weight. About 100 pounds of aluminum would be obtained from the alternators.

Jan 1, 1976

By McHenry Mosier

A skull breaker has demonstrated its advantages for secondary breaking in a limestone quarry by entirely displacing secondary blasting . It has reduced safety hazards to workmen, increased the number of quarry operating days , and has lowered mining costs by 2.7 cents a ton. It is believed that the application of the skull breaker can be made economically advantageous in the surface mining of other commoditics .

Aug 1, 1948

By L. B. Pankratz

The heat contents of the sesquioxides of erbium, holmium, thulium, and ytterbium (Er203, Ho203, Tm203, and Yb203) in the cubic crystalline form were measured over the temperature range from 298° to 1,800° K. The erbium and holmium sesquioxides gave regular heat content-temperature curves. Thulium sesquioxide had a minor thermal anomaly near 1,680° K, with a heat absorption of 310 cal/mole; similarly, ytterbium sesquioxide had a minor anomaly near 1,365° K, with a heat absorption of 150 cal/mole. The heat content results are presented in both tabular form (at 100° intervals) and in algebraic form. Entropy increments, corresponding to the tabulated heat content results, also are listed.

Jan 1, 1963

By R. V. Ramani, R. A. Jankowski, R. Bhaskar

"The spatial distribution of airborne dusts, deposition of dust in the airway, as well as the effect of airflow velocity and particle density on dust behavior in mine airways were studied in a set of experiments performed in a mine airway under controlled conditions. Considerable deposition of dust near the source was indicated. Pronounced effects due to velocity were observed in ambient dust concentration and deposition along the mine airway, both in the respirable and the total size ranges. Cross-sectional concentration measurements indicate an increase in concentration from the roof to the floor. The average cross-sectional concentration is about 75% of the concentration in the center of the airway.IntroductionA number of studies have been performed since the early 1950s on the behavior of dust in mine air (Bradshaw and Godbert, 1954; Dawes and Slack, 1954; Bradshaw et al., 1954; Hall, 1955-56; Reinhardt, 1971; Ford, 1971; Courtney et al., 1982). While the experimental data available from these studies are indeed useful in understanding dust cloud behavior in a specific situation, no generalized conclusions can be drawn because of the lack of data on parameters such as flow velocity, size distribution of the source dust, and particle density. These change from mine to mine or even within the same mine. The present study is aimed at providing a better understanding of the temporal and spatial behavior of dust particles in underground' mine airways (National Academy of Sciences, 1980). The characteristics studied encompassed airborne concentrations and floor depositions over the entire size range as well as the respirable size range. The experimental results in this paper are intended to complement a mathematical model developed to predict ambient concentration and deposition of airborne dust in mine airways (Bhaskar and Ramani, 1986)."

Aug 31, 1989

By Paul Biggs

This report presents information on 77 waterflood projects in 31 Montana oilfields. The study shows the locations of the projects, the sources and amounts of injection water, and the results in oil produced. Waterflooding, a secondary recovery technique, began in Montana about 40 years after the initial oil discovery in 1920. Often, the difference between water disposal by injection and pressure maintenance operations is not clear. Water injected at the projects in 1973 was 157.7 million barrels. In 1973, the 31 fields having waterflood projects produced 28.3 million barrels of oil valued at $88.4 million. Both in volume and value, this represents over 80 percent of the State's 1973 oil output. The projects are making possible the recovery of additional oil, thus contributing to the conservation of oil and lessening the impact of the current oil shortage.

Jan 1, 1976

By Jr. Sharkey

The Bureau of Mines investigated gases from flash and laser irradiation of Pittsburgh seam (hvab) coal to determine the action of high temperatures on coal. Temperatures in excess of l,000° C were reached with both types of irradiation. Craters about 300 microns in diameter were produced in the coal with millisecond pulses from the laser unit rated at 1.7 joules' output. Gaseous products from laser and flash irradiations in vacuum contained 21 and 8 percent acetylene, respectively. Diacetylene, vinylacetylene, and other products to molecular weight 130 were indicated in the mass spectrum of the gas from the laser study. Single experiments were also conducted in which the laser energy, particle size of the coal, and atmosphere were varied. The results indicated that the distributions of products obtained from the flash and laser irradiations of coal were different from that produced in high-temperature carbonization.

Jan 1, 1966

By K. K. Kelley, L. B. Pankratz

The heat contents of four silicate minerals -- akermanite , cordierite , gehlenite , and merwinite --were measured from 298 ° to around 1,700 ° K by the dropping method . The results were compiled into tabular and equation forms suitable for thermodynamic calculations . The heat contents of these compounds are nearly additive with respect to their constituent oxides .

Jan 1, 1964

By Gary P. Sames

Shale roof deterioration in coal mines. caused by ventilation air humidity fluctuations, is a common ground control problem. Shale roof deterioration often results in increased accidents, decreased production, inadequate ventilation, and increasing operating costs in maintaining haulage roads and airways. The results of Bureau of Mines research indicate that air tempering entries are an effective method of controlling deterioration prone shales. Some of the conclusions and recommendations drawn from Bureau research include (1) moisture sensitive shales will react adversely to moisture gains and losses, (2) the majority effect of specific humidity fluctuations can be concentrated in and absorbed by tempering entries, (3) tempering entry panels should be located as near to the main intake as possible, (4) tempering panels should be designed for a conservative recovery and provide a minimum of 20-to 30-min air residence time, (5) ventilation and escapeway requirements must be considered early in panel design, and (6) an efficient support and sealant plan can increase the life expectancy of a tempering panel.

Jan 1, 1985