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By Gabriel Braga Regattieri Sampaio

Neste trabalho, determinou-se o calor latente de fusão da liga A356.0 através da Curva Zero, calculada pelo método Newtoniano de análise térmica linear. Para tanto, foram feitos experimentos com dois Copos de Análise Térmica (CAT) em moldes cerâmicos. Utilizou-se um sistema de aquisição de dados configurado para obtenção das curvas de resfriamento experimental (CR). Para o processamento matemático da curva de resfriamento e a determinação da Curva Zero Newtoniana (CZN) utilizou-se um programa comercial com planilha de cálculo. Obteve-se os valores de 321J/g e 345J/g para cada copo de análise térmica. Comparando com a bibliografia cujo valor do calor latente é 403J/g, a precisão foi de 82%.

Aug 16, 2017

By Lis Nunes Soares

A Vallourec Tubos do Brasil é uma siderúrgica integrada com produção de tubos de aço sem costura. A qualidade e o acabamento superficial dos tubos estão diretamente relacionados com o processo de laminação pelo qual eles passam. Um fator extremamente importante para um bom processo de laminação é uma boa lubrificação da peça de laminação, o mandril. Durante o processo de laminação, o mandril passa por várias etapas além da lubrificação, incluindo etapas de aquecimento e resfriamento, que se repetem em ciclos de laminação. Um dos principais parâmetros do processo de produção que influenciam a lubrificação do mandril é justamente o perfil térmico e a temperatura superficial do mesmo. O perfil térmico do mandril afeta a aderência do lubrificante em sua superfície. Visando a melhor compreensão do processo, esse trabalho tem como objetivo propor um modelo matemático em diferenças finitas que descreva a evolução do perfil térmico do mandril durante o processo de laminação de tubos sem costura. O mesmo modelo matemático é validado através de engenharia reversa. A proposta do modelo matemático é ser usado na análise de possíveis métodos de pré-aquecimento de mandris antes da lubrificação, diminuindo ou eliminando assim possível sucateamento de peças e paradas da linha de produção por esse motivo.

Jul 31, 2018

By Juan Ramírez L

El presente texto describe la aplicación del método de evaluación de volquetes en minería de cielo abierto, donde se considere las variables que influyen en la operación y la factiblidad del mísmo a posteriori. Para ello, se han desarrollado dos programas para calculadora HP-41CV, que dado su carácter voluble y poder de resolución, se adecúan a este tipo de trabajo. En este sentido, el cálculo del equipo de acarreo conlleva el cálculo del mineral a extraer, cálculo del stripping, proyección de avances, velocidades y ciclos y número de volquetes necesarios para movilizar el tonelaje proyectado.

Nov 8, 1984

By Jorge Olivari Ortega

El presente texto describe la relación de la expansión territorial del inca Cápac Yupanqui, último gobernante del Hurinsuyo con la explotación de los placeres auríferos en la zona de Huayllaripa (Apurímac). El gobierno del inca Cápac Yupanqui se caracterizó por el interés de la producción minera -en tanto estos minerales servían para ennoblecer el Coricancha, adoratorio construido especialmente para venerar al sol, dios tutelar de los incas. De otro lado, los mitimaes eran los migrantes que trabajaban la mina de oro a través del proceso de exploración, preparación y finalmente, de derribo del material aurífero. Para ello emplearon el método minero cochazo el cual consiste en almacenar grandes cantidades de agua (cocha) y precipitarla violentamente (lloclla), causando un fuerte derrumbe del material aurífero, que se depositará por gravedad en los canales de captación de las partículas de oro (toclla). Los placeres auríferos son la acumulación de fragmentos de piedras, arena, arcilla y de partículas de oro que provienen de la desintegración de vetas y mantos auríferos, y que por diversos agentes naturales como agua, nieve, viento y otros, han sido transportados, reunidos y concentrados en diferentes lugares.

Nov 1, 2015

By Mario Alejandro Bendezú

Este trabajo tiene como objetivo mostrar la importancia de la minería junior en la creación de nuevas minas, así como en el mercado de valores. Este documento tocará los retos por los que está atravesando el sector junior, y analizará las acciones, factores, estrategias y documentos públicos provistos por ciertas mineras junior que lograron llegar a su objetivo. En el primer capítulo de esta tesis se abarcará los conceptos esenciales para poder conocer la minería junior en el cual se precisarán definiciones tale como la de éxito, valor y objetivos que buscan alcanzar este tipo de empresas. En el segundo capítulo se analizará cómo la minería junior ha contribuido en la exploración minera a nivel global. De la misma manera, se identificarán los principales desafíos que están impidiendo que las mineras junior continúen con sus operaciones exploratorias normalmente. El tercer capítulo tiene como finalidad realizar el estudio y análisis de aquellas mineras que llegaron al éxito, para realizar esto se ha recopilado toda la información relevante que puede haber contribuido a que la minera junior analizada haya cumplido su objetivo. Por último, se presentaran una serie de ratios, estrategias y variables extraídos del análisis de las mineras junior exitosas para poder identificar a las actuales junior que están encaminadas al éxito.

Sep 21, 2015

By Mario Bendezú

Este trabajo tiene como objetivo mostrar la importancia de la minería junior en la creación de nuevas minas, así como en el mercado de valores. Este documento tocará los retos por los que está atravesando el sector junior, y analizará las acciones, factores, estrategias y documentos públicos provistos por ciertas mineras junior que lograron llegar a su objetivo.

May 1, 2008

By Nelson Rivera

Dado que la producción de oro en el Perú permaneció estática durante los últimos treinta años, se buscó una solución a través del empleo de una tecnología más eficiente. Por ello, el presente texto señala la revisión de la tecnología empleada en varias zonas de Brasil como el uso de dragas de cucharas y se aperturó de nuevos frentes de explotación aurífera en la zona selvática para incrementar las divisas que el país necesita.

Nov 1, 1985

By Robert Rother

El presente texto señala el proceso de exploración y preparación que anteceden la etapa de la producción de mina. Para ello, es necesario ubicar un depósito mineral donde se clasifican en vetas, zonas de cizallamiento, contactos, substituciones y diseminaciones, que se distinguen por la forma de la zona débil en la costra terrestre. Asimismo, es necesario anotar datos como: ubicación, acceso, altura sobre el mar, características de la región, labores, posición del cuerpo mineralizado, sobrecarga, caja y ganga, tectónica y todo lo que se puede ver efectivamente. Posteriormente se evalúa el título de las propiedades, mapeo topográrico y geológico del yacimiento, sistema y costo del muestreo planeado, estudio de las vías de acceso y transportes, reservas de mineral, así como considerar el programa de producción (abastecimiento de agua, mano de obra, escala de operación, tratamiento metalúrgico, valor de la producción, costos de operación, utilidad de operación).

Jan 1, 1964

By G. Langlands

"R. Tenbergen Is this flotation machine suitable in the flotation ofInco ball mill discharges where we have a coarse feed at 60% solids?Reply Experience has shown that there is not a significant increase in the wear life of these machines when handling coarse material (8 mesh) at 60% solids. A common practice in Europe is shut down on the week-ends.The material is allowed to settle and on start-up an injectic of air for 15 seconds is sufficient prior to start-up. At,mining we put our unit in the middle of a bank of 44 cells and in order to ensure severe sanding we shut the aker cell down while the remaining cells kept running. After 20-25 seconds of air the cell started without trouble.P. Mahant Is there a build-up inside the impellor shaft housing? Falconbrige Ltd.Reply There is no sand build-up but rather a scale build-up which due to a flexing action frees itself periodically. Part of the design of the machine permits a water injection into the shaft housing to free any build-up. This is done in Europe during the week-end shut down."

Jan 1, 1984

By Alexander Blatt, Franz-Werner Gerressen

Diaphragm wall technique is usually used to construct structural elements in the ground, commonly used for retention systems, permanent foundation elements or deep groundwater barriers, named Cut-Off-Walls (COW). Recent developments proof, that the technology also satisfies the demands for using the diaphragm wall technique for bulk sampling purposes. Such kind of new ideas required the adaption of equipment and tools for a depth capability never reached before by a trench cutter in any commercial application worldwide. Compared to the development of increasing depths, especially inner-city applications with limited space, demand a minimization of equipment to accommodate such projects. The paper will focus on the developments and solutions generated to fulfill these requirements and will give an outlook to future developments. Further it describes finalized reference projects and will give a general outlook on future trends and developments. The Paper/The Presentation explains as well the installation process in general.

May 1, 2022

D. C. JACKLING, the father of the porphyry coppers, has been honored for his pioneering in that field. There is another facet to Mr. Jackling's activities, one which now may prove an even greater monument than the big coppers-the story of his venture in taconite beneficiation. The essence of his porphyry development was mass handling of material. Not alone mining on a large scale, which was done on the Mesabi Range at the turn of the century, but the integration on a previously unknown scope of mining, milling, concentration, and in many cases, of final reduction to metal at the site. This was mass production applied to mining, treatment of a very low grade source material, previously considered submarginal.

Jan 1, 1954

By AIME AIME

DONALD K. CRAMPTON, present Chairman of the Institute of Metals Division, A.I.M..E., is well known by nonferrous metallurgists in all countries for his research work on the fabrication and properties of copper and its alloys including investigation of season- and stress- corrosion cracking. He is also well known, at least by many metallurgists in the United States for the proficiency with which be carries on his hobbies, in i:lrlditlg photography. gardening, and golf

Jan 1, 1941

4.5.1 General The provisions of the article shall apply to the design of axially and laterally loaded driven piles in soil or extending through soil to rock. 4.5.1.1 APPLICATION (Revised Article 4.3.1.1) Piling may be considered when footings cannot be founded on rock, or on granular or stiff cohesive soils within a reasonable depth. At loca-tions where soil conditions would normally permit the use of spread footings but the potential for scour exists, piles may be used as a protection against scour. Piles may also be used where an unacceptable amount of settlement of spread footings may occur. 4.5.1.2 MATERIALS Piles may be structural steel sections, steel pipe, precast concrete, cast-in-place concrete, prestressed concrete, timber, or a combination of materials. In every case, materials shall be supplied in accordance with the provisions of this Article.

Jan 1, 1989

By Alexandre Rodizio Bento

Os acidentes de trabalho estão cada vez mais presentes em indústrias de vários segmentos, inclusive no setor automotivo. Devido ao trabalho no chão de fábrica deste setor utilizar interferência humana em alguns processos e operações, onde o trabalhador compartilha o ambiente produtivo com máquinas automatizadas. Estas máquinas podem causar graves lesões temporárias ou permanentes no trabalhador, podendo chegar até a morte. Neste cenário, este trabalho apresenta um estudo da implantação da pirâmide de Heinrich como forma de informar e prevenir acidentes na indústria automotiva. É detalhado o processo de implantação da pirâmide na linha de produção. Esta implantação contribui na prevenção de acidentes, gera alertas de possíveis riscos, comportamentos inseguros e incidentes. Os resultados desta implementação acabam aumentando a segurança no ambiente de trabalho, reduz custo com acidentes dentro da indústria, que permite investir cada vez mais em métodos para prevenir e gerar um ambiente de trabalho livre de acidentes no setor automotivo.

Aug 8, 2018

By V. Ushakov, P. Bogdan

Daily production scheduling in a highly dynamic smelter environment has always been a great challenge for the operation management due to a significant amount of uncertainties. Planned and unexpected equipment failures, various energy outages, inaccuracies in flow and mass balancing, manpower availability conflicts and other constraints make the job of daily production planning exceptionally difficult. This paper discusses a general scheduling approach utilized by the production management of the Phelps Dodge Miami Smelter (the Smelter). It also describes logical assumptions and some practical software solutions that have been exploited by the Smelter managers to assist the front line supervisors in dealing with daily planning activities for several years.

Jan 1, 2007

By John Rushton

Surface mining, from ore extraction to processing, requires many types of equipment to obtain the final product. Mine equipment often includes shovels, drills and haul trucks. Ore processing equipment, including plants, mills and concentrators, are also part of surface mining operations. Surface mining operations emphasize production. Production is where the bills are paid and fortunes are made. However, there must be support to keep the equipment operational. To most production people, equipment maintenance is a necessary evil. Maintenance is not glamorous work. It is often neglected when praise is being passed around. It is easy to recognize higher production, greater capacities, faster cycle times or more loads hauled. But who cares if an engine is replaced in 12 hours instead of 48? The answer is, everyone should - from the hourly miner to the mine manager. Surface mining equipment needs constant maintenance work. It must be lubricated, components replaced, electrical problems repaired and other problems addressed. Repair work for any surface equipment takes time away from production. It costs money. Maintenance costs cannot be avoided. However, they can be minimized. Minewide communication should include operations cooperating with maintenance. Traditionally, operations resist surrendering equipment to maintenance if it can continue to produce. The rationale is, every load that can be hauled today is money in the bank. If the unit is taken down, the money is lost. This thinking is prevalent in many surface mining areas, including the mill. "Not on my shift," the operator thinks. "Let the next crew worry about it. The problem with this thinking is in probability and statistics. The longer equipment goes without maintenance work, the higher the probability of equipment failure. When the failure does occur, it is certain to cause the equipment to remain down longer than if the maintenance department had been allowed to take it down. Many mining operations have closed early in their lives because of poor maintenance practices. This has become the industry standard because substandard levels of performance are acceptable. Management believes it gets five to six hours of work from maintenance people during an eight-hour shift. Actually, the industry average is less than two hours of work per shift. Real productivity levels of less than one hour are not unusual. There are few exceptions. However, a daily work schedule (DWS) will increase productivity at many properties by 50% to 100%. A 200% improvement is not unusual. The DWS will work. Maintenance people are among the most intelligent and motivated people on the property. They deserve the chance to be productive. [ ] In preparing a DWS, management needs to understand two productivity principles - the productivity spread and the real maintenance workday.

Jan 1, 1997

By AIME AIME

ONE hundred and eighty-three A.I.M.E. members, W. S. Morris with an excellent technical program, John Suman, "oil" President of the Institute, and a Texas norther blew into Dallas for the fall meeting of the Petroleum Division at the Adolphus Hotel, Oct. 16-18. and the most successful result will give future meeting committees a high mark to equal. People were still talking of the terrific heat the week before and it was quite noticeable that with the lowered temperatures, the members were in fine fettle for the technical sessions. The total attendance on Friday noon was

Jan 1, 1941

By Robert Cameron, Colin Ashton, John MacNeil, Leo Piciacchia

"The in pit dam construction and utilities relocation, known as the East Mine Corridor Relocation (EMCR) project, was developed to extend the life of the east side of the Base Mine pit by two veal's. This will result in the recovery of an additional 80 million barrels of oil and delay expenditures associated with the opening of the North Mine by two years. To accomplish this, a large in pit earth structure was required to provide a new embankment foundation for relocating a public highway, four powerlines, a natural gas back-up pipeline, a substation, and a conveyor train. This structure would also he required as a temporary dam 10 contain mature fine tails on the west side until mining is completed in the east mine corridor area, that will then be filled with fluid.The in pit dam, known as The Highway Berm, is 2.5 km long, 63 m high and has 42 million m3 of engineered soil added to the already existing end-dumped soil volumes. To complete the design and construction of a structure of this magnitude, in the very short time frame of two-and-a-half years, presented many new challenges. The main challenges faced were: designing while construction was ongoing; designing without the use of clay cores or sand filters; using relatively non-select overburden material; proper dewatering and base preparation; changing from construction of 50 m high spoil piles to a high specification construction operation; compacting lifts with heavy haulers; constructing during the winter; and monitoring movement of the structure with satellites."

Jan 1, 1995

By M. Nakamura, T. Akamatsu

Embankment dams are often constructed on soft rock foundations in Japan, so it is important to precisely predict deformation of the foundations due to fill placement at the design stage. In order to accurately evaluate the settlement and the strain of the rock foundation surface during construction, the influence of the scattering of the deformability of foundations on the deformation behaviour should be investigated. In this paper, a method of evaluating the settlement and the strain of the rock foundation surface during construction was studied with stochastic deformation analysis considering the scattering of the deformability of the dam foundation. Based on the analytical results, a dam foundation design using the deterministic method considering the scattering of its deformability was discussed. Da in Japan Uferdämme of auf weichen Felsfundamenten gebaut werden, ist es wichtig, die Verformung der Fundamente auf Grund der Platzierung der Aufschüttungen bereits in der Planungsphase genau vorherzusagen. Im Zusammenhang mit einer genauen Beurteilung der Senkung sowie der Belastung der Felsfundamentoberfläche während der Bauarbeiten sollte auch der Einfluss der Streuung der Verformbarkeit der Fundamente auf das Verformverhalten untersucht werden. In der vorliegenden Studie wurde die Bewertungsmethode zur der Senkung sowie der Belastung der Felsfundamentoberfläche während der Bauarbeiten mit Hilfe von Wahrscheinlichkeitsanalysen der Verformung unter besonderer Berücksichtigung der Streuung der Verformbarkeit der Dammfundamente untersucht. An Hand dieser analystischen Ergebnisse wurde das Design der Dammfundamente dann enthusiastisch mittels deterministischer Methoden hinsichtlich der Streuung der Verformbarkeit diskutiert. Comme les barrages en remblai sont souvent construits sur des fondations rocheuses tendres au Japon, il est essentiel de prévoir précisément les déformations des fondations causées par la mise en place du remblayage durant la phase de conception. Afin d’évaluer avec exactitude le tassement et la déformation de la surface du rocher de fondation durant la construction, l’effet de la dispersion de la déformabilité des fondations sur le comportement de déformation doit être étudié. Dans cette étude, l’auteur a étudié la méthode d’évaluation du tassement et de la déformation de la surface du rocher de fondation durant la construction en procédant à une analyse aléatoire/stochastique de la déformation et en prenant en considération la dispersion de la déformation des fondations du barrage. En se basant sur les résultats de l’analyse, la conception des fondations de barrage avec la méthode déterministe considérant la dispersion de sa déformabilité a été activement discutée.

Jan 1, 2003

By A. Kalmes, B. Dehler, D. Kopp

Nutrien has six potash mines in Saskatchewan and has been proactive in maintaining the integrity of their tailings facilities through ongoing assessment, design, operation, inspection, and monitoring. Nutrien commissioned a system inventory and semi-quantitative risk analysis (SQRA) of all dikes to further environmental stewardship at their potash facilities. The inventory assessed nearly 100 dikes; each dike was rated according to a probability and consequence factor and assigned a risk score. The risk scores were used to develop a risk matrix for each of the six sites and risk-response actions for each dike and segment. The inventories and SQRAs will help each site assess priorities for investigation and risk mitigation, if necessary. The study results will also help Nutrien refine corporate wide tailings governance standards and demonstrate compliance with various governance regulatory obligations.

Mar 2, 2022