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By A. U. Seybolt, R. E. Honnemon

THE purpose of this communication is to present activity data of nickel in the Ni-A1 binary system that was obtained for oxidation studies in this system. This data has been calculated from previous aluminum activity data at 1000°C1,2 by two types of Gibbs-Duhem integrations. These results should be of particular current interest to oxidation studies of aluminide coated nickel-base superalloys3 as well as other problems. The aluminum activity of Steiner and Komarek1 is plotted in Fig. 1 as a function of composition in Ni-A1 alloys at 1000°C. The dashed parts of the aluminum curves represent our approximate extrapolations from the directly measured regions. In the terminal solution regions (a and L phases) standard parabolic solution functions of the following form are assumed: where i is the component subscript, Ki is a constant at a fixed temperature, and xi is the atom fraction. The resultant nickel activity curve at 1000° C from the Gibbs-Duhem integration4 of the aluminum data is shown in Fig. 1. The solubility ranges of the phases present in the Ni-A1 binary at 1000°C are also denoted at the bottom of Fig. 1. Corresponding values of the nickel activity, aNi and yNi, are listed in Table I at useful compositional intervals. including phase boundary values. The aNi and yNi data listed in Table I are subject to the uncertainties present in the experimental aluminum activity data1 and to deviations from parabolic solution behavior in the terminal solutions. The errors introduced into aNi and yNi due to the parabolic solution assumption are expected to be relatively small (<20 pct of the values given) in all the phases except the liquid phase. Some deviation from parabolic solution behavior in the liquid phase is indicated

Jan 1, 1970

By Alfonso Ballón

La producción de hierro por medio del alto horno se realiza en condiciones limitadas en lo que refiere al combustible reductor coque, ya que necesita mayores proporciones de materias volátiles en los carbones originarios. Por ello, la presente investigación remarca la importancia del uso del horno eléctrico de reducción o de cuba baja, como unidad metalúrgica más idónea para producir arrabio de variadas cualidades. Asimismo la aplicación de este horno, permite extender su producción en la industria siderúrgica de algunos paises europeos y asiáticos, y por qué no dentro de América Latina.

Jun 20, 1954

By F. W. Bradley

GOLD is a large subject. One could talk about its geological or mineralogical occurrences, prospect- i11.g for it, mining of .it, its metallurgy or its marketing; but I have decided to limit my discussion to gold as a business-that is, to its production and marketing. In the production of gold, it is necessary to consider the many possible sources, the quantities available, the capital and operating costs and the chances of price-breaking competition. So in the following remarks I shall endeavour to point out that though gold is found in every formation constituting the earth&apos;s crust, though it is possible to-find it free in great concentrated placer deposits on the surface, though there are still large unprospected areas of both the surface and the crust, though it may be possible to produce it by the cheapest labor on earth, and by processes not as yet developed, it still has an unlimited market at a definite price. There is no reasonable fear of disturbance by the finding of bountiful deposits, or by cheapening the cost of production due to devaluation, or by the development of any easy processes for direct, or for by product, production.

Jan 1, 1932

By Bernard Lewis

This report summarizes fundamental research end technical studies conducted in the Explosives and Physical Sciences Division, Region VIII, of the Bureau of Mines in the 2 years July l, 1950, to June 30, 1952. It is the fifteenth of a series of, ordinarily, annual reports whose aim has been to provide the reader with a resume of the research results that have appeared in published form during each fiscal year under the authorship of members of the staff. These are referred to throughout the report. ACKNOWLEDGMENTS Acknowledgments art, made to the following members of the Division wider whose mediate supervision the described studies were carried out. Stuart R. Brinkley, Jr., chief, Mathematical and Theoretical Physics Section, and special assistant to the chief of the division.

Jan 1, 1953

By S. J. Jung

A fundamental study of fragment size distribution and characteristics of fracture pattern is presented for the dynamic penetration of a conical bit into coal block. In this paper, damaged zones during crater formation and fragment size distribution were studied. Bit with a sharper tip angle and a smooth body configuration performed better penetration. Results suggest that in coal cutting the trend should be toward the face cleat direction using a sharper angled tip bits which consumes less energy for an optimum range of penetration depths, thus attaining maximum cutting efficiency and reducing fine fragments.

Jan 1, 1989

By Hanry A. Guillén Vilca

La estabilidad de una excavación subterránea y el trabajo estructural del sostenimiento depende de tres factores principalmente: la calidad del macizo rocoso, tipo de sostenimiento y procedimiento constructivo. En ese sentido, el presente texto tiene como objetivo optimizar las operaciones de minado en CMHSA, bajo los términos de seguridad, productividad y economía a través del análisis de respuesta determinística de las variables de decisión tiempo de autosoporte (relación Esfuerzo – Deformación)y la interacción de la Curva Característica del Terreno vs Curva Característica del Sostenimiento planteada por Lombardi.

Jan 1, 2017

By Jorge Nelson Rivera Guillén

"La tierra es una unidad de un complejo astral que se observa desde la antigüedad en sus aspectos exteriores y su dependencia del sistema solar. En ese sentido, el presente texto señala la génesis y evolución de los minerales comprendido en la tierra a través de cuatro libros denominados ""Los misterios del planeta tierra"", donde se mencionan los aspectos tectónicos preliminares y preparatorios para la disgregación de la Pangea Nueva, cuya “lenta explosión” ocasionó la separación de las placas tectónicasy la acción de fuerzas distensionales que actuaron sobre los fragmentos que generan desequilibrios barotérmicosinternos y la formación de zonas magmáticas y metalizaciones."

May 1, 2015

By H. Nelisse, S. K. Patra, A. Natani, S. Rakheja

The current laboratory methods for assessing the vibration attenuation performance of seats involve repetitive trials with a number of human occupants, and raise certain ethical concerns. Moreover, the measurements with human subjects yield considerable variability in the data. Alternatively, several anthropodynamic manikins have been developed for effective assessments of the coupled seat occupant system [1]. The effectiveness of a manikin in predicting the response of a coupled seat-occupant system lies in its ability to reproduce the biodynamic response of the seated human body in terms of force-motion relationship at the body-seat interface, such as apparent mass (APMS). A number of prototype manikins have thus been developed on the basis of biodynamic characteristics of vertical vibration-exposed seated occupants of different body masses in the vicinity of 5th, 50th and 95th percentile male population. This study concerns with the analysis of a passive prototype manikin to enhance its ability to reproduce the idealized APMS response characteristics of the vibration-exposed seated human subjects defined in ISO-5982[2] for mean body masses of 55, 75 and 98 kg. Methods The APMS responses of a prototype anthropodynamic passive manikin were thoroughly characterized in the laboratory under different excitations and body mass configurations. The manikin was designed with sufficient flexibility to configure mechanical-equivalent models corresponding to seated body masses of 55, 75 and 98 kg, by adding/removing specified masses and springs (Fig. 1). The manikin, configured for a specific body mass, was positioned on a rigid seat without a backrest, which was fixed to the force platform of a whole-body vertical vibration simulator. The simulator was programmed to synthesize random vertical vibration with flat acceleration power spectrum in the 0.4-20 Hz frequency range with two different magnitudes: 1 and 2 m/s2 overall rms acceleration. The total static and dynamic forces of the manikin to and the seat were measured using the force platform, while a single axis accelerometer was installed on the seat pan to measure acceleration due to vertical excitation. The measured data was appropriately corrected for the rigid seat inertia force, and the apparent mass [ ]

Jan 6, 2006

By Miyuki Morioka, Michael J. Griffin

Discomfort, annoyance, or interference with activities due to exposure to vibration is only expected if the vibration exceeds the threshold for the perception of vibration. When there is more than one vibration input to the body (e.g. at the hands, seat and feet), the sensation is first experienced at the location with greatest sensitivity. Knowledge of differences in the thresholds of perception for vibration at the hand, seat, and feet should assist the identification of sources of discomfort caused by vibration. Perception thresholds for vibration have been determined in several studies, but only a few studies have investigated perception thresholds in the horizontal direction for hand-transmitted vibration 1, 6 or whole-body vibration 4-5, and there has been little consideration of perception thresholds for the foot resting on a vibrating surface. This study determines absolute thresholds for the perception of sinusoidal lateral vibration, examining the effect of vibration frequency (8 to 315 Hz for the hand and foot; 2 to 315 Hz for the seat) and the effect of input location (the hand, the seat and the foot). Methods Three groups of twelve males aged between 20 and 29 years participated in the experiment. Subjects in each group attended an experiment to determine perception thresholds for lateral vibration via either a rigid handlebar (30 mm diameter) at the left hand (left hand), or a rigid contoured seat (250 mm x 150 mm), or a footrest at the left foot (30.5 mm x 10.5 mm with 10-degree inclination). For the non-exposed hand (right hand) or foot (right foot), a stationary handle and footrest with the same dimensions as the vibrating handle and footrest were provided so that the same body posture was adopted among the three groups of subjects. An up-down (staircase) algorithm was employed to determine thresholds in conjunction with a three-down one-up rule. A single test stimulus (2.0 seconds) was presented with a cue light illuminated during this period. The task of the subjects was to indicate whether they perceived the vibration stimulus or not. The threshold was calculated from the mean of the last two peaks and the last two troughs, omitting the first two reversals. Results The median absolute thresholds of the 12 subjects determined at each frequency for the hand, seat and foot are shown in Figure 1. A frequency dependence of the threshold contours within the investigated frequency range is evident, with similar shape to the threshold contours

Jan 6, 2006

By J. Tumialán

El presente trabajo realiza un estudio comparativo de las propiedades físicas y químicas de tres nitratos de amonio, cuya interpretación se relaciona con las conclusiones sobre estudios de AN-FO realizados en la Universidad de Missuri. Básicamente se evalúa los factores de campo que afectan la performance del AN-FO, como el confinamiento, diámetro del hueco, inicio de la carga y mezcla del explosivo, así como se mide la factibilidad de disparar al AN-FO sin una dinamita. Los tajeos de producción de la mina Casapalca sirvieron de ejemplo para ejecutar dichos disparos, encontrándose que el AN-FO francés es el más adecuado y sensible en torno a la performance de los otros explosivos, dado sus componentes como su ahorro de consumo.

Nov 20, 1972

By Adderly Reeves, Renzo Dávila, Cinthya Lozano

Anglo American Quellaveco S.A. inició sus actividades productivas en el año 2022 con un Centro Integrado de Operaciones (IOC) que centraliza el monitoreo y control de todas las actividades productivas de la cadena de valor y articula decisiones ágiles basadas en datos. A través de la gestión operativa del IOC se contribuye significativamente al cumplimiento del programa semanal de producción, empleando aplicaciones tecnológicas avanzadas y dentro un marco de filosofía de operación integrada que no sólo integra físicamente el control de las estaciones de trabajo para cada una de las operaciones unitarias de la cadena de valor, sino que también está habilitada para trabajar con una filosofía de operación integrada.

Sep 29, 2023

By A. Garassino

A pile design was performed for a thermal power station in Egypt and more than 4000 piles were to be driven. Technical economical reasons suggested the choice of driven composite LACOR piles designed for very high specific loads. Some uncertainties on the behaviour of the pile soil system suggested to perform a test on an instrumented pile. Scope of the test was to verify the possibility of developping the required bearing capacity within the range of the allowable pile settlements values and the effect of the pile joint enlargement on that portion of skin friction to be developped by the upper pile section.

Jan 1, 1991

By Kenneth E. Hay

Researchers from the U.S. Bureau of Mines conducted a field study to assess the safety of remotely controlled mobile roof supports (MRS) in a retreat pillar mining operation, Data were collected to provide the Mine Health and Safety Administration with criteria needed to develop guidelines for MRS use and to determine if precursors could be identified that would alert miners to imminent roof falls. Two test sites at which two different support methods-MRS&apos;s and posts were used and were monitored to obtain information on entry stability. Pressure transducers and string pots were installed on all four MRS&apos;s to obtain loading and displacement information. and roof bolt load cells. sonic probes, extensometers, and survey targets were installed in the surrounding entries to obtain information on ground behavior. Results showed a larger increase in roof bolt loading and roof movement when MRS&apos;s were used, especially in the intersection area. Roof bolt loads in the entries showed decreases in load when the MRS&apos;s were set and increases up to 11,1 kN (2,500 lbf) when the MRS&apos;s were unloaded. Unloading of one MRS in a pair did not significantly increase load on the other. MRS&apos;s I and 2 usually had the higher loads, with these loads increasing as the pillars on each side were being mined. MRS 3 normally had lower loads than I and 2: however, it also experienced some very high loads when in the last position near the pushout. MRS 4 usually had the lowest loads, primarily because it was located near the solid pillar that was not being mined.

Jan 1, 1995

By José Beltrán

El monitoreo de condiciones es una herramienta importante en las operaciones mineras -en tanto asegura una buena salud de los equipos de producción. En ese sentido, el presente texto muestra los resultados de un equipo evaluador que opera el sistema de condiciones MineCare y valida distintos casos de análisis reales y cotidianos, verificando las ventajas de utilizar esta herramienta en ejemplos reales para las mejores prácticas operacionales dentro de la operación extractiva minera.

Mar 1, 2016

This Kaiser Engineers report on the feasibility of surface mining on the North Slope of Alaska has considered the quantity and quality of the North Slope deposits with attention paid to the economic, technical, and environmental constraints of the mining systems suggested for the three candidate minesites at Kukpowruk River, Elusive Creek, and Kuk River. Site selection, based on coal rank and quality as well as seam thickness and geometry, also considered demonstrated and hypothetical reserves relative to three mining systems (dragline, shovel, dragline and shovel), mining equipment requirements, infrastructure, and transportation relative to the Arctic environment and costed for potential markets. Throughout the report the delicate permafrost environment has received particular consideration. Recommendations based on the technical, economic, and environmental feasibility of mining the coal deposits of Northern Alaska by surface mining techniques have resulted in two conclusions: 1. The coal deposits can be mined with currently available technology; 2. It is uneconomic to mine these coals given current coal resource estimates, costs, and market conditions. A literature survey is included in appendix.

Jan 1, 1977

By Juan L. Luque Lanza

Durante las fases de minado como la exploración, desarrollo, preparación y explotación de una zona mineralizada, surgió la necesidad de clasificar geomecánicamente el terreno a través del uso los conceptos básicos de la mecánica de rocas y la integración de dicha disciplina al planeamiento del minado de una mina subterránea. Por ello, el presente texto describe el proceso de esta metodología que consiste en la clasificación del terreno según los grupos de similar comportamiento y la elaboración de planos geomecánicos, con la finalidad de encontrar la relación existente entre el tiempo límite y el espacio activo para una excavación subterránea, diseño y cámaras pilares en la mina subterránea de Yauricocha.

Aug 26, 1988

By Herminio Nieto, Andy Corales

Este documento plantea una gestión de los recursos hídricos eficiente mediante la automatización del balance de aguas operacional. Esta herramienta busca mejorar la eficiencia y precisión en el seguimiento y gestión de los recursos hídricos utilizados en la operación minera, a través de la recopilación, análisis y visualización de datos en tiempo real. La automatización del balance de aguas se basa en datos recopilados de flujómetros, sensores de monitoreo, registros de campo y otros, que utiliza algoritmos de procesamiento de datos para calcular el balance de aguas bajo los lineamientos del Consejo Internacional de Minería y Metales (ICMM).

Sep 29, 2023

An examination is made of some of the consequences of a magmatic gas phase developed during a late stage of differentiation of an acidic magma. Elements possessing halides with high partial pressures (Sn, Mo, W) may be removed from the magma by distillation into gas bubbles in the manner suggested by Fenner (1933). The common chalcophile elements are not affected by this mechanism, but form sulphides which may become attached to rising gas bubbles by one of three distinct mechanisms. The gas bubbles may then carry the sulphides upwards and concentrate them in some favourable locus, giving rise to an ore-forming fluid. The process would operate selectively upon different sulphides and is capable of providing an explanation of the paragenetic succession observed in ore deposits as well as other important geological criteria of ore genesis.INTRODUCTIONThere is a widespread belief among contemporary geologists that a large and important class of ore deposits is genetically related in some way&#183;to acidic igneous rocks. This class includes the tin-tungsten-molybdenum-bismuth type of mineralization as well as a variety of sulphide deposits.A basic problem confronting explanation of the genesis of these deposits is the manner in which trace elements which were originally widely dispersed in granitic magmas were segregated therefrom and concentrated into economic mineral deposits.The principles underlying the formation of one group of minerals deposits (pegmatites) related to granitic magmas ate reasonably well understood, largely due to the labours of Goldschmidt and his school. However, many geologists have noted that there appears to be some sort of fundamental discontinuity between pegmatite formation and the origin of the more common hypogene ores, particularly sulphides.Accordingly it has been suggested that these ores...

Jan 1, 1956

By D. B. RUSHhIORE

I. INTRODUCTION. OF primary importance in mine-installations is the hoist, which has a very direct bearing on the successful operation of a mine. Conditions vary greatly with different mines, and especially in different localities. Such factors as depth, incline, the number of levels, permissible or desirable speeds, conditions of ore, etc., are always more or less special in each case. Veins of ore are never exactly duplicated, and the nature of the ground through which shafts are sunk may considerably modify permissible values. As mining-laws are made by the different States, they necessarily vary somewhat, and, even when not fully observed, they introduce factors which qualify the conditions of hoisting men and ore. The amount of timbering required is often of importance as relating to hoisting-conditions. Methods of loading ore affect the time required, as also does the question of the use of cars or skips. Safety-precautions must be very carefully considered, and the number of men in each mine, the number of compartments, and often the method of removing water from the mine, must. have careful consideration. While a general discussion of the subject. of hoisting is possible, most cases are entirely special, and can be considered only in connection with the peculiar conditions pertaining to that particular installation. The cost of installation of the hoisting-plant may be an appreciable amount, while the cost of raising the ore may be but a small part of the total operating-charge. In many cases, however, the output of the mine is limited by the capacity of the hoist, and the latter thus becomes of the first importance. * Presented also, by mutual agreement, at the meeting of the American Institute of Electrical Engineers, New York, N. Y., Mar. 11, 1910.

May 1, 1910

By H. A. Wheeler

IT may surprise some of our members to learn, among the industries based on the mineral resources of the United States that of clay now ranks third, being exceeded in value of product only by pig-iron and coal. The present annual value of clay-products exceeds the value of the outputs of gold and silver, and also exceeds the combined values of copper, lead, zinc, aluminum, mercury, antimony and nickel. These facts are shown in Table I. which gives the statistics for the year 1902

Jan 1, 1905