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By Heitor Cristo Clem de Oliveira

O objetivo deste trabalho é estudar a reação de dessulfuração, envolvidas no processo de pré-tratamento de ferro-gusa. A princípio, as misturas utilizadas foram caracterizadas e estudadas através do software de termodinâmica computacional (FactSage 7.1). Em seguida, os resultados obtidos através do estudo termodinâmico computacional foram comparados com aqueles obtidos mediante os testes experimentais a 1400°C. As misturas dessulfurantes tiveram como base a CaO com três tipos de fundentes, fluorita, sodalita e barrilha, além da utilização de alumínio como elemento desoxidante. Os testes experimentais permitiram identificar que a adição de 0,1% em massa de alumínio no gusa, eleva a taxa de remoção de enxofre principalmente no instantes iniciais do processo. Com a utilização da termodinâmica computacional pode-se mostrar que a reação de dessulfuração no ferro-gusa é exotérmica para os teores de silício encontrados no processo. Além disso, a termodinâmica computacional também contribui, em alguns casos, para a análise de compostos sólidos que podem se formar na escória e limitar as reações de dessulfuração.

Oct 30, 2017

By Stefany Castro, Miguel Pineda, Jonathan Calle, Sebastián Osorio

Sociedad Minera Cerro Verde cuenta con un nivel de monitoreo completamente automatizado, el resultado final se presenta en una plataforma digital dinámica de visualización de resultados de calidad y niveles de agua subterránea (Dashboard) en tiempo real, permitiendo así un seguimiento constante y la identificación de algunas variaciones en los parámetros más relevantes, pudiendo ejecutarse respuestas inmediatas ante cualquier alerta o cambio de las condiciones del agua subterránea o parámetro hidroquímico. El nivel de instrumentación automatizada de Sociedad Minera Cerro Verde se basa en las combinaciones de captura y almacenamiento de datos y las combinaciones de cobertura de señal según disponibilidad en diferentes sectores de la mina.

Sep 30, 2022

By R. Duinker

"This paper, an update to the 2003 paper titled "Knowledge, Technology and Profit" (Twigge-Molecey, 2003) analyzes 45 "problem projects" from the mining and metals industry over the last eleven years representing $133 billion in CAPEX. The projects have been designated as "problem projects" as they did not meet their owner’s initial expectations for project performance as defined in the paper. This paper explores some of the challenges that were present, through interviews with the knowledgeable individuals that were familiar with the projects and investigations using publically available information. The aim of the exercise was to identify the key challenges faced by the projects, and the contributing factors that led to the project failures so that the lessons can be applied to future projects.The project challenges have been categorized into four themes, technical, organizational, environmental & social and missing "homework" prior to board approval. Of noteworthy interest is that environmental permitting aspects have risen to become a significant and notable contributor to problem projects in 11 years from 2003 to 2014. It is further observed that many projects have been challenged by increasing size and complexity and with execution in more remote locations since the previous paper.It is a reality that every project will face challenges. Some projects are simply more challenging than others, and success or failure of the project is often determined by whether the project team is fully prepared to respond to the challenges. This in turn is largely dependent on whether the project "homework" was adequately completed and considered for all aspects of the project."

Jan 1, 2015

By Wade L. Karlsen

"Revision surgery to replace joints in the human body requires materials that are strong, long-lasting, and biocompatible. Metallic implants made of cobalt-chromium-molybdenum alloys are already popular because of their proven corrosion and wear resistance properties, but there is an on-going effort to economically improve their performance. Alloying with inert nitrogen can enhance the mechanical properties of the alloy, enhance its corrosion resistance, and elevate the temperature at which the metallic implants can be thermally treated, without increasing the threat to the human body. The current work has produced a high-nitrogen Co-Cr-Mo alloy through HIP consolidation of metal powders that have undergone nitriding in a mechanically fluidized bed. The already fine microstructure of the powders combined with the increased nitrogen content resulted in significant property gains in the consolidated materials.IntroductionMetallic implants made of cobalt-chromium-molybdenum alloys are already popular because of their proven corrosion and wear resistance properties, but there is an ongoing effort to improve their performance. Research on a Stellite 21 cobalt-chromiummolybdenum alloy has shown that nitrogen alloying can be desirable from several standpoints [l]. Firstly, it has indicated that nitrogen can enhance the mechanical properties of the alloy, which could allow more demanding implant designs. The same work also demonstrated that nitrogen can elevate the temperature at which the metallic implants can be thermally treated, which is desirable in situations in which surface textures are to be sintered to the implant to enhance its fixation properties. Finally, that research work discovered that, not only does nitrogen not harm the corrosion resistance of the cobalt-chromium-molybdenum alloys, but it may in fact enhance it. Combining this with the fact that small amounts of nitrogen are not considered a threat to the human body, makes nitrogen alloying an attractive alternative for enhancing the properties of Co-Cr-Mo."

Jan 1, 2000

By Elmer H. Citron

The Monterey Coal Company, a wholly owned subsidiary of The Carter Oil Company of Houston, Texas, recently awarded a contract to build the Monterey No. 1 Preparation Plant, which will be located near Carlinville, Illinois, to the McNally Pittsburg Manufacturing Corporation. The preparation plant will be one of the most modern jig preparation plants in the State of Illinois. Illinois No. 6 coal will be delivered by a 48" slope belt having 35-degree carrying idlers, operating at 650 FPM and operating on an incline of nearly 17 degrees. The slope belt is driven by two 450 BP motors and will deliver the mined coal at the rate of 1800 TPH to a stationary step-type ' screen having six-inch openings. The overproduct from the stationary screen will discharge into a 10' x 24' McNally Rotary Breaker and the underproduct will bypass the rotary breaker. The rotary breaker is equipped with heavy manganese screens with 6 ½" diameter openings. The sized 6" x 0 coal from the stationary step screen and the rotary breaker will be discharged by gravity to a 4%" raw coal incline storage belt. The 48" raw coal storage belt will deliver the 6" x 0 sized coal at the rate of 1800 T?H to an 8000 ton concrete raw coal silo, 70 feet in diameter and 1x7 feet high. The 6" x 0 sized coal will be drawn from the concrete storage silo by seven (7) 36" wide reciprocating plate feeders. Five feeders are to have constant speed drives at a rated capacity of 145 TPH each. Two (2) feeders will have remote con- trolled variable speed drives, to provide a varying feed.

Jan 1, 1970

By Afonso Garcez de Azevedo

As primeiras argamassas utilizadas em construções pelo homem continham em sua composição, materiais argilosos. Porém, por ser um material com muitas cargas elétricas livres, as argilas reagem constantemente com a água, ocasionando grande variação linear que acaba causando fissuração nas argamassas feitas com esse material. Assim, para solucionar esse problema, passou-se a utilizar cal hidratada no lugar dos materiais argilosos. Dessa maneira, mesmo não sendo composta por argila, a argamassa mantém sua trabalhabilidade. Nesse cenário, o presente trabalho teve como objetivo balancear estequiometricamente a cal hidratada e as argilas estudadas, para utilizar essas quantidades em argamassas para revestimento, barateando assim o material. Para encontrar esse balanceamento estequiométrico calculou-se a massa molar para um mol de cal hidratada e para um mol teórico de argila. Assim foram estipuladas algumas proporções possíveis de balanceamento da equação de reação cal+argila. Além disso, foram confeccionados corpos de prova, variando as quantidades de argila e cal, para realização de ensaios de capilaridade, a fim de comprovar a eficácia dos resultados encontrados no balanceamento teórico.

Oct 30, 2017

By Jorge Cangahuala

"El nuevo concepto que se establece es la Neuro prevención derivada como una disciplina de las neurociencias que busca conocer cómo trabaja nuestro cerebro, sus potencialidades y limitaciones al momento de enfrentar situaciones con potencial de algún incidente o accidente laboral. Identificado estos indicadores y conexiones neuro centrales podemos tener mapeado cómo se comporta nuestro cerebro, como lo refleja en el comportamiento (acto seguro e inseguro), su análisis y que técnicas vamos a implementar en cada proceso."

Sep 1, 2017

By Milton E. Jennings

On May 11, 1977, the SAMARCO 20-inch, 396-kilometer (246-mile) Pipeline was placed in service. This system represents the latest thinking in slurry pipeline design and is one of the main contributors to the viability of the SAMARCO Project. This paper presents the background, description and latest information on the system's operation. Special attention is given to the handling limitations of the slurry and to the unique hardware requirements.

Jan 1, 1978

By Harry R. Johnson

Laboratory experiments were conducted to study the carbon deposition characteristics of a high-gravity, paraffin-base crude oil. The results of these experiments indicate that a fuel supply adequate to initiate a combustion wave can be deposited in high-gravity-oil reservoirs. These results are significant because there has been considerable doubt whether oils over 35° API gravity are able to deposit sufficient fuel. Considered in these studies were the effects of air flux, temperature, initial oil saturation, and time on carbon deposition. Conditions that maximized carbon deposition in the laboratory and an understanding of the nature of carbon formation are shown by graphical interpretation of the data. Statistical techniques were used to design and analyze the results of the retort tests. For the same amount of laboratory work, this approach yields more information about the systems that were studied than the classical method of research presently used in many laboratories. In addition, the accuracy of calculating the effect of each variable on carbon deposition is twice that of the classical approach. This paper develops the statistical approach to research without complex mathematics, thus enabling the reader to grasp the concept of how statistics can be applied to study many complicated problems.

Jan 1, 1966

By Luis Soto, Brian Pajares

El producto denominado “TEMSE”, que proviene de las siglas de “Telemetría y Salud de equipos”, es un conjunto de hardware y software desarrollado por la empresa “Soluciones SITECH Perú S. A.”, creado para solucionar una problemática presente en la gran mayoría de operaciones mineras subterráneas en Perú. Debido a que un gran porcentaje de estas, actualmente no cuentan con una infraestructura que facilite el acceso a Internet a lo largo de sus operaciones, generando la ausencia de conocimiento de la información de productividad y mantenimiento de sus operaciones subterráneas.

Sep 29, 2023

By K. Takahashi, I. Iwasaki

it is well known1 that racemic mixtures of optical isomers can be separated by passing their solutions through a column packed with r- or 1-quartz powder so that one of the isomers becomes adsorbed selectively on the asymmetric quartz surfaces. Although the natural occurrence of r- and 1-quartz is more or less equally distributed, some localities show enough deviations toward a higher proportion of l-quartz2 to suggest that optical isomerism might influence quartz flotation. Beta-amines have an asymmetric carbon atom, and therefore optical activity may be expected. Beta-amines are reported to behave quite differently from alpha-amines in the flotation upgrading of certain oxidized iron ores.3 It is of interest, for both practical and theoretical reasons, to determine whether or not optical isomerism plays a role in the amine flotation of quartz. In this article the results of Hallimond tube flotation tests and of adsorption measurements using d-beta-phenylisopropylamine on both r- and 1-quartz are compared. D-beta-phenylisopropylamine was chosen for the tests because it is commercially available in optical isomers. MATERIALS AND METHODS Brazilian quartz crystals were hand-sorted according to the difference in trigonal trapezohedral faces, and each crystal was further checked by the Airy's spiral.4 The respective crystals were then crushed, and the -150 + 200-mesh fractions were screened out for the Hallimond tube tests. The samples were cleaned by brief leaching with warm, dilute hydrochloric acid, and then by repeated rinsing with distilled water. In preparation for the adsorption measurements, they were then dry-ground in a pebble mill for several hours, washed a few times with distilled water, and finally dried in a vacuum desiccator. By means of the Krypton gas adsorption method, the specific surfaces of r- and 1-quartz samples were determined to be 27,700 and 19,800 sq cm per gm respectively, the difference being due mainly to the decantation procedure rather than to the inherent difference in their grindability. D-beta-phenylisopropylamine was the only collector used in the study. It was solubilized by neutralizing with 110% of the stoichiometric requirement of 0.1 N hydrochloric acid. The specific rotation of the d-beta-phenylisopropylamine was determined with a polari-meter using sodium D line to be, Although the d-beta-phenylis~prop~lamine showed absorption maxima in the wave length region of 250 to 270 millimicrons, due presumably to the phenyl group, these peaks were too sensitive to be used for colorimetric determination of the residual concentration in the adsorption measurements. The amine-picrate method, used in the colorimetric analysis of dodecylammonium chloride,' was found to work satisfactorily for the d-beta-phenylisopropylamine. The adsorption densities were thus determined after equilibrating 40 gm of the ground quartz sample with 300 ml of solution by tumbling in separate glass-stoppered Erlenmeyer flasks for one hour. EXPERIMENTAL RESULTS Fig. 1 presents the adsorption densities of d-beta-phenylisopropylamine on the r- and 1-quarts in the pH range of 6 to 7.5. In agreement with data reported in the literature, the adsorption density of d-beta-phenylisopropylamine was slightly higher on the r-quartz than on the 1-quartz, although the difference was not as pronounced as one might expect from the capacity of r-quartz and 1-quartz to separate racemic

Jan 1, 1969

By James N. Bayne

An examination and analysis of Landsat digital data in the monitoring of surface mines in selected counties of South Carolina.

Jan 1, 1979

By Qinmeng Wang

The oxygen bottom blown copper smelting process is a new technology which has been widely applied to the copper production in China. In this work, a computational thermodynamics model for this technology has been established, based on smelting mechanism and theory of Gibbs free energy minimization. The calculated results from the model agree well with the actual industrial data, indicating that the model can be used for the predictions under different operating conditions. The tendencies of the key parameters (such as Cu losses and Fe3O4 content in slag) and the distribution ratios of the minor elements (such as Pb, Zn, As, Sb and Bi) can be predicted by adjusting the oxygen/ore ratio charged into the bottom blown copper smelting furnace. The model can be used to monitor and optimize the industrial operations of the oxygen bottom blown copper smelting process.

"In a continuing investigation into the development of uranium alloys for armament applications, some complex base alloy corn positions were modified by varying the amount of alloying elements and by removing one or two of the alloying elements in turn from the base alloys. These uranium-base alloys were specially formulated in a search for heat-treatable, high-strength, ductile, high-density alloys. All alloys studied were ternary, quaternary or more complex alloys of uranium with molybdenum, zirconium, niobium and vanadium. Each cast alloy was studied under three different heat-treatments, and its mechanical and corrosion properties were determined. It was found that although most of the alloys studied had the hardness and strength required, they were extremely brittle and notch-sensitive under tensile stresses."

Jan 1, 1968

By N. Snyders, I. Mwandawande, S. M. Bradshaw, M. Karimi

"Computational fluid dynamics (CFD) was applied to predict the average gas holdup and the axial gas holdup variation in a 13.5 m high cylindrical column 0.91 m diameter. The column was operating in batch mode. A Eulerian-Eulerian multiphase approach with appropriate interphase momentum exchange terms was applied to simulate the gas-liquid flow inside the column. Turbulence in the continuous phase was modelled using the k-_ realizable turbulence model. The predicted average gas holdup values were in good agreement with experimental data. The axial gas holdup prediction was generally good for the middle and top parts of the column, but was over-predicted for the bottom part of the column. Bubble velocity profiles were observed in which the axial velocity of the air bubbles decreased with height in the column. This may be related to the upward increase in gas holdup in the column. Simulations were also conducted to compare the gas holdup predicted with the universal, the Schiller-Naumann, and the Morsi-Alexander drag models. The gas holdup predictions for the three drag models were not significantly different. IntroductionColumn flotation is an important concentration technology that is used in the mineral processing and coal beneficiation industries. The growing interest in the use of column flotation in mineral processing has been attributed to the simpler flotation circuits and improved metallurgical performance compared to conventional flotation cells (Finch and Dobby, 1990). Flotation columns have also found other applications outside mineral processing, such as de-inking of recycled paper (Finch and Hardie, 1999).In column flotation, a rising swarm of air bubbles generated by means of air spargers is employed to collect the valuable mineral particles and separate them from the gangue minerals in a countercurrent process. Wash water, which is continuously fed at the top of the column, is used to eliminate entrained particles and stabilize the froth. The column volume can be divided into two sections – the collection zone in which the bubbles collect the floatable mineral particles, and the cleaning zone (or froth zone) where product upgrading is enhanced through the removal of unwanted particles entrained in the water mixed with bubbles from the collection zone."

Jan 1, 2019

By Daniel Bloomfield

ONE of the major problems of management is how to restore in some measure the personal relation-ship between employer and employed which, in the days of small concerns, meant better morale among employees. The complexity of industry today, the heterogeneous mass. of workers employed, many .of them new to this country and to its institutions, the inability of those whose task it is to get out production to spend much time on the problems of labor-all these and many other factors serve to make of great impor-tance the question of how to establish more satisfactory mutual good will. While there is no such thing as a sure cure for labor troubles, in spite of the fact that charlatans have been selling alleged cures to guileless employers, study and experience have brought to light methods of approach to the problems confronting management in its relation to labor that are well worth consideration. Labor problems must be approached with common sense and an open mind. Facts must be the basis of action. So it is with the question of morale in industry. What makes or breaks morale? What are the forces behind the actions of men? What is there in one man that makes him act differently from another man under similar circumstances? How are men affected by the actions of others in their own group or by the actions of those under whose supervision they work? These are questions that must be carefully studied if we are, to get at the bottom of industrial unrest. It is an easy thing to say that good will can be created by "treating men right." That involves so many things and points of view that it will hardly serve as a full answer to our problem; but it is a good starting point if we mean by right treatment the payment of wages consistent with the well being of the worker and his family as members of the community, and if we also mean the provision of sanitary, wholesome working conditions and a working schedule that does not overtax the worker physically, and mutuality-a give and take relationship. With this as a basis we can go a step farther and see what else can be done to promote better relations between management and the workers.

Jan 9, 1922

Longhole open stoping was introduced in the zinc-rich 'B' lode at New Broken Hill Consolidated Limited (NBHC) during 1968. Since then one longitud- inal and a series of transverse longhole open stopes have been developed. The longholes are drilled using Gardner Denver airtrac drilling jumbos and the broken ore is loaded from drawpoints and transported to chutes using Wagner ST5 scoop- trams. The holes were drilled from sill stopes 160 ft apart. The width of an emptied transverse longhole stope was successfully widened by blasting rings of blastholes drilled parallel to the stope wall. Proposed stope and pillar designs for a series of transverse longhole open stopes were assessed using a method of finite element analysis, applied to a longitudinal section through the area. Blastholes have been surveyed for dip and bearing using an Eastman borehole survey camera. The data produced has provided the basis of a study of blast- hole deviation. Deviation of boreholes is considered to be the major cause of the formation of benches in longhole stopes.

Jan 1, 1971

By Oliver Bowles

In 1943 the Bureau of Mines began a review of trends in consumption and prices of the more important nonmetallic minerals. The first report covering building materials4/ appeared in December of that year. The present paper, which deals with chemical raw materials and fertilizers, is the second of the series. The 34 years from 1910 to 1943, for which statistics are presented herein, comprise periods of uneventful peace, unparalleled prosperity, industrial depression almost to the point of stagnation, and two wars of world proportions.

Jan 1, 1945

By Bruna de Camargo Lemos

O objetivo deste trabalho compreende a realização da síntese de SnO2 dopado com aditivo Sr2 contendo diferentes quantidades molares de SrO (X)SnO2+(1-X)SrO, em que o cátion Sr2+ foi introduzido através do nitrato de estrôncio variando de 5 à 50 % em mol para uma mistura tanto em meio aquoso quanto em meio alcoólico, seguida da calcinação do pó resultante que é feita à 700°C com uma taxa de 10°C/min. Análises de caracterização como difração de raios X, área específica, calorimetria exploratória, picnometria a gás e determinação do ponto isoelétrico das suspensões aquosas foram realizadas de modo a verificar qual o agente dispersante mais apropriado para as características ácido-básicos da suspensão em questão. A partir deste determinar o potencial zeta do composto estudado através da eletroforese. Compostos intermediários a base de estanato de estanho foram identificados, e a deposição por eletroforese foi realizada com sucesso, uma vez que foi possível obter uma suspensão estável a partir dos pós cerâmicos produzidos.

Aug 16, 2017

By Alberto Ramirez Sauri

El concepto de rentabilidad se relaciona con un sistema de medida de rendimiento expresado en términos de utilidad de una inversión, una actividad económica o negocio. Mientras que la productividad se relaciona con la cantidad de producto extraído con determinados factores de producción y factores. Por ello, el presente texto analiza las tendencias de los diferentes grados de utilidad con el capital invertido, los márgenes con respecto al ingreso y su relación directa con la productividad del sector minero. Así también es necesario que el sector minero uniformice sus criterios contables para poder llegar a obtener indicadores de rentabilidad, productividad y de otro carácter económico, que permita a cada unidad ubicarse con relación al promedio del sector, facilitándole al empresario el conocimiento necesario para optimizar su gestión en beneficio del sector y la economía del país.

Nov 1, 1972