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By Moacir Medeiros Veras

A tecnologia de sensor-based sorting faz uso de sensores high-tech para pré-concentrar seletivamente partículas de minérios que tenham teores toleráveis para planta de beneficiamento, rejeitando as partículas que são totalmente estéreis ou rejeitos. A pré-concentração de carvão assistido pelo método Dual Energy X-Ray Transmition possibilita separar seletivamente o carvão com melhor quantidade de matéria orgânica das rochas silicáticas com maior densidade. O objetivo desse trabalho foi investigar a afinidade da tecnologia de sorting na pré-concentração do carvão mineral da Carbonífera do Cambuí/PR assistido por sensor de raios-x. Os testes foram realizados em dois lotes cujo range granulométrico foi -4”+2” e -2”+1”. A pré-concentração foi feita em 2 cortes de separação, o primeiro para retirar o rejeito e o segundo para obter 2 tipos de produtos. Os resultados indicaram que 52,15% da massa foi rejeitada, concentrando 47,85% do material de carvão na fração média -2”+1”. Na fração grossa -4”+2” foi rejeitado 62,51% da massa e concentrado 37,49% de carvão. As análises imediatas dos pré-concentrados mostraram que na fração grossa houve redução de 44,57% de cinzas totais e houve aumento de 4,59% para 8,29% de enxofre [S], enquanto na fração média a redução foi de 36,98% de cinzas totais e de 1,19 % [S].

Oct 30, 2017

By Clyde Sitterud

Presentation Agenda ?Global Mining Tire Demand ?What is driving it? ?Latest Situation ?How long it will last? ?Michelin?s Response to Increase Supply ?New plant ?Additional presses ?Recommendations for Mining Users ?Treat tires as your major assets ?Areas of attention that will produce immediate results

Jan 1, 2005

By Leo F. Reinartz

It was with humility that I accepted the invitation of the Board of Directors of our Institute to deliver the Twentieth Howe Memorial Lecture. Many previous lecturers could speak from personal experience of the great work done by Professor Howe. It was not my privilege to be one of his students but, indirectly, I came under the influence of his work many years ago. My mentor in Metallurgy at Carnegie Institute of Technology, Prof. Fred Crab tree, was an ardent admirer of Professor Howe and his work. Professor Crabtree taught me early to appreciate Professor Howe's love of truth and keen desire to find a scientific reason for every metallurgical phenomenon. In this early search, Professor Howe encountered many unexplainable facts. Nevertheless, in the classic text, "The Metallurgy of Steel," published in 1891, he indicated that he believed Research could light the way. Under the heading of "The Treachery of Steel" he said: "In the early use of Bessemer and Open Hearth Steel, many then unexplained and hence mysterious failures occurred. With our present knowledge, an easy explanation of most of them would probably have been seen. But even today certain unexplained and apparently inexpli- cable failures occur in steel; inexplicable in spite of full and intelligent investigation." Then Professor Howe continued to talk about "the trustworthiness of steel" in the following manner: First, the steel-maker has learned by experience. He knows today far better the effects of a high percentage of carbon or of phosphorus; of cracks, pipes and blow-holes; of segregation and imperfect mixing; of over-heating; of finishing too hot or too cold. Knowing, he guards against them more effectually, and keeps at home much steel that he would formerly have sent into the market. Those who would not, or could not learn and do, have been driven out of the business; the conditions necessary for producing good sound steel by the acid Bessemer and the acid Open Hearth processes have been mastered. By and by, the basic process came along with new conditions, new liabilities to unsoundness, a great hue and cry about mysterious fractures followed, and Lloyd's register provisionally forbade the use of basic steel. Much basic steel was irregular and brittle throughout; too much carbon, too much phosphorus, too cold teemings—imperfect mixing. Still there was little doubt that, with further experience, these difficulties of the basic process would be mastered as those of the acid process had been. This shows that Professor Howe could not take anything for granted. Believing that careful research would find the answer to all mysterious phenomena, he was several generations ahead of the practical acceptance and adoption of this principle.

Jan 1, 1943

By Leo F. Reinartz

It was with humility that I accepted the invitation of the Board of Directors of our Institute to deliver the Twentieth Howe Memorial Lecture. Many previous lecturers could speak from personal experience of the great work done by Professor Howe. It was not my privilege to be one of his students but, indirectly, I came under the influence of his work many years ago. My mentor in Metallurgy at Carnegie Institute of Technology, Prof. Fred Crab tree, was an ardent admirer of Professor Howe and his work. Professor Crabtree taught me early to appreciate Professor Howe's love of truth and keen desire to find a scientific reason for every metallurgical phenomenon. In this early search, Professor Howe encountered many unexplainable facts. Nevertheless, in the classic text, "The Metallurgy of Steel," published in 1891, he indicated that he believed Research could light the way. Under the heading of "The Treachery of Steel" he said: "In the early use of Bessemer and Open Hearth Steel, many then unexplained and hence mysterious failures occurred. With our present knowledge, an easy explanation of most of them would probably have been seen. But even today certain unexplained and apparently inexpli- cable failures occur in steel; inexplicable in spite of full and intelligent investigation." Then Professor Howe continued to talk about "the trustworthiness of steel" in the following manner: First, the steel-maker has learned by experience. He knows today far better the effects of a high percentage of carbon or of phosphorus; of cracks, pipes and blow-holes; of segregation and imperfect mixing; of over-heating; of finishing too hot or too cold. Knowing, he guards against them more effectually, and keeps at home much steel that he would formerly have sent into the market. Those who would not, or could not learn and do, have been driven out of the business; the conditions necessary for producing good sound steel by the acid Bessemer and the acid Open Hearth processes have been mastered. By and by, the basic process came along with new conditions, new liabilities to unsoundness, a great hue and cry about mysterious fractures followed, and Lloyd's register provisionally forbade the use of basic steel. Much basic steel was irregular and brittle throughout; too much carbon, too much phosphorus, too cold teemings—imperfect mixing. Still there was little doubt that, with further experience, these difficulties of the basic process would be mastered as those of the acid process had been. This shows that Professor Howe could not take anything for granted. Believing that careful research would find the answer to all mysterious phenomena, he was several generations ahead of the practical acceptance and adoption of this principle.

Jan 1, 1943

By Staff

A major emphasis of the U.S. Bureau of Mines is to perform research on the prevention of fatal accidents at mining operations. The leading cause of fatalities in the underground coal mining industry is groundfalls. This proceedings volume presents several new developments that are helping to prevent fatalities and reduce injuries by groundfalls. The papers focus on the problem from two different perspectives. About half of the papers present information and techniques that can be used to train and motivate miners to protect themselves from groundfalls. The other papers explain how to identify and respond to various geologic conditions that affect the stability of the mine roof. Of the 95 groundfall fatalities that occurred during 1986-90, 75% took place in Kentucky, West Virginia, and Virginia. The rate of groundfall fatalities was much higher at small mines. During 1986-90, the rate of groundfall fatalities at mines employing fewer than 20 people was 4.3 times higher than the rate for larger mines. Because so many groundfall fatalities are occurring at relatively small mines in the southern Appalachian coalfields, many of the papers focus specifically on the needs of this category of mine operations.

Jan 1, 1992

By N. A. Eilertsen

Procedures of mining high-calcium limestone underground at the Kimballton mine of the Standard Lime and Cement Co. in Giles County, west-central Virginia, are described. Drilling and blasting procedures arc discussed in detail, and direct mining costs are tabulated in percentage of total cost. Output, about 1,725 tons of limestone a day, is attained with heavy trackless equipment by the room and pillar method of ruining; modified by benching floors. Operating features include underground air compression, electric-eye control of curtained doorways, use of a single jumbo drill rig for all drilling, and an effective plan for maintenance of equipment. The company's safety program has contributed to an outstanding safe mining record. The mina is integrated with a plant on the property which converts the stone to metallurgical and chemical grade lime.

Jan 1, 1964

By Jorge Chira

INGEMMET realizó el proyecto “Estudio de los Recursos Minerales del Perú” con el objetivo de identificar las áreas prospectivas para propiciar actividades de exploración minera por parte de la empresa privada. Entre las funciones ejecutadas está la “Prospección Geoquímica Regional de Sedimentos de Quebrada”, donde se ha recopilado 5,636 muestras de sedimentos de quebrada, las que fueron analizadas por Au y 32 elementos a fin de elaborar posteriormente el Atlas Geoquímico del Perú. En ese sentido, el presente texto señala el uso del software para el tratamiento estadístico de los resultados a través del soporte técnico de la empresa GEOSOFT. Dicho software genera una tecnología confiable así como lo versatilidad para el manejo e interpretación de diversos datos. También se desarrolló el programa OASIS – MONTAJ; módulo CHIMERA con el cual se pueden manejar en forma exacta una gran cantidad de información geoquímica empleando controles de estándares y duplicados.

Aug 25, 2002

By Lowell B. Moon

Concern over possible wartime shortages finally resulted in passage of the Strategic Materials Act in 1939. As authorized by one section of this legislation, the Bureau of Mines proceeded to investigate deposits of seven strategic minerals with the objective of developing tonnages of low-grade material that could be mined in an emergency. During the war, the size of the program and the number of strategic minerals were increased, and the objective was the more immediate one of aiding production. Since the war, the size of the program has been reduced, but the number of minerals on the strategic list continues to be large. The objective has returned to that of 1939. In the course of the program, more than 10,000 examinations were made and about 1,300 projects were run on deposits of 33 different commodities. A considerable contribution to war production was made in six of the commodities investigated, and a minor contribution was made in twelve others. Substantial reserves have been indicated in 19 minerals. Private interest is currently active in some of the deposits developed in 14 commodities.

Jan 1, 1950

By Jaime Tumialán de la Cruz

El presente texto busca describir las experiencias adquiridas en la mina de Cerro de Pasco a través del uso del "scooptram" eléctrico "LHD" de 2.2 yds. cú., marca "Jarvis Clark, a fin de mostrar su aplicación en otras minas cuyos problemas y características se asemejan a Cerro de Pasco. Los objetivos del empleo de este equipo son: aumentar la productividad en las áreas minadas por el método corte relleno descendente-mecanizado, mecanizar parte de la mina con equipos "LHD", pese a los problemas de ventilación, las temperaturas altas y reemplazar estos mismos equipos por aire acondicionado. En este sentido, se logró demostrar la eficacia del equipo eléctrico, especialmente en el uso de minas antiguas y de mayor profundidad, así como se mejoró las condiciones ambientales de trabajo y el costo de mantenimiento de los equipos eléctricos resultó más económico que las de diesels.

Nov 20, 1978

By C. E. White

History The Con-Rycon mine is situated in the Yellowknife mining district, North West Territories, 608 air miles north of Edmonton, Alberta. The earliest reported discovery of gold in the area was made in 1898 but no extensive exploration occurred until 1928. The birth of Yellowknife as a mining community took place in 1934 with the staking of the Rich group and subsequent shipping of 16 tons of high grade ore. The Giant group was also among the claims staked in 1934, and later staking showed a tendency to close the gap between these two properties. In the fall of 1935, the A.Y.E. claims, situated south of the Giant group, were staked to cover a discovery of the Geological Survey of Canada and, after general release of the Survey's information, the adjoining ground was staked. These claims included the Con, Negus, Meg, and Kam groups. In 1936 four lapsed claims were re-staked as the P and G group and later acquired by Rycon Mines, Limited, controlled by the Consolidated Mining and Smelting Company of Canada, Limited. The Con and various adjacent groups owned by Cominco are now operated with the Rycon under one management. Surface trenching on the Con property started in 1936 and, during the fall and winter of 1936-37, a 60- foot 5 ft. by 9 ft. inclined prospect shaft was sunk. The encouragement provided by the shaft and diamond drilling in 1937 led to the decision to establish a mining plant, and in August, 1938, the 100-ton cyanide mill produced its first brick- the first gold brick poured in the history of the North West Territories. In November, 1938, the mill was enlarged to a 175-ton capacity and operated at this rate until 1941, when refractory ore was encountered. This situation was met by the installation of flotation and roasting units and, at the same time, the milling capacity was increased to 300 tons daily. Labour shortages and Government restrictions forced a reduction of output and in 1943 milling was suspended while mine development continued on a reduced scale throughout the war years. The present full-scale of operations was resumed in 1946 and the total production to the end of 1948 amounted to 288,853 oz. gold and 72,347 oz. silver.

Jan 1, 1949

By Breno Carvalho de Oliveira

Neste trabalho é apresentado uma ferramenta de otimização multiobjetivo para planejamento da manutenção de ativos ferroviários. A aplicação foi modelada com base no problema do Caixeiro Viajante Multiobjetivo, considerando como objetivos a minimização da postergação da manutenção dos equipamentos e do deslocamento da equipe de manutenção. Foi utilizada uma instância real de 17 cidades que são atendidas por uma única equipe de manutenção. A ferramenta de otimização consiste na combinação do algoritmo SPEA2 (Strength Pareto Evolutionary Algorithm), da methaheurística GRASP (Greedy Randomized Adaptive e Search Procedure) e de uma heurística de busca local em vizinhança, cada uma com seu papel específico dentro da otimização. O algoritmo foi capaz de mapear soluções melhores que a atualmente adotada pela empresa, proporcionando uma economia significativa no valor total a ser gasto em um ciclo de manutenção dos ativos ferroviários.

Oct 30, 2017

By Julie Culverhouse, Dennis Grimm, Kieran Harding, Jean-Francois Boulanger

"Agrium’s Canadian Phosphate Business (CPB) is comprised of Kapuskasing Phosphate Operations (KPO) in Northern Ontario, Canada’s only operating phosphate mine, and Redwater Phosphate Operations (RPO) in Alberta, which manufactures the fertilizer from KPO’s concentrate.Production from KPO’s South Pit commenced in 2009 and introduced contaminant problems: high aluminium from crandallite and kaolinite clays. These issues caused a drastic decrease in P2O5 recovery and throughput in both plants. KPO attempted to reduce Al clays by means of aggressive desliming. Meanwhile RPO experienced high amounts of dissolved metals in their feed that are detrimental to fertilizer production.This paper covers the mineralogy of the problem, its impact on contaminant separation at KPO, on RPO’s process and on Agrium’s Canadian Phosphate Business as a whole.Potential solutions to the problem are discussed and analysed, including a process change to deslime high aluminium streams more aggressively and high grade ore flotation, which is atypical at KPO. The latter is a demonstration of the value of communication between the concentrator and the client, as KPO accepted a recovery loss and increased production costs in order to increase overall CPB profits. General lessons learned are discussed, followed by a section on ore blending.INTRODUCTIONAlthough the existence of the Kapuskasing phosphate deposit has been known since the 1970s, it’s only since 1999 that Agrium has been operating the Kapuskasing Phosphate Operations (KPO). The mine consists of three major pits (Center, North and South) from which a mining contractor hauls the apatite ore to the Agrium concentrator. The beneficiation plant processes the ore, separating contaminants such as Fe, Mg and Al which are detrimental to its client, Agrium’s Redwater Phosphate Operations (RPO). The KPO concentrate is finally thickened, filtered and dried before being shipped by rail to RPO.At the Redwater plant, the KPO concentrate is added to a sulfuric acid solution in an attack tank, to create a phosphoric acid solution and gypsum:"

Jan 1, 2011

By Henrique Silva Furtado, Flaviani Marculano Marchesi, Silas Gambarine Soares, Elton Volkers do Espírito Santo, Felipe Fardin Grillo, Heitor Cristo Clem de Oliveira

Devido ao aumento da restrição do teor de enxofre nos aços torna-se necessário investigar a eficiência do processo de dessulfuração de ferro gusa. Portanto, o objetivo deste trabalho é empregar diferentes matérias-primas e fundentes como cal calcítica, sodalita, pré-cal, mistura padrão, fluorita, escória de KR, borra de alumínio e B2O3, a fim de encontrar a composição com maior eficiência de dessulfuração, relacionando-a ao fator de dessulfuração, obtido pela termodinâmica computacional. Os testes foram realizados a 1350°C, em uma atmosfera inerte com agitação constante. Os resultados mostraram que a mistura com maior eficiência foi aquela com 69% de cal, 5% de sodalita, 15% de pré-cal, 6% de escória KR e 5% de B2O3.

Oct 1, 2019

By André Luíz Moreira de Souza

O objetivo do trabalho é demonstrar a otimização de recursos com a implantação de grades de agendamento e gestão logística via SAP do processo de abastecimento da Vallourec Tubos do Brasil, com carvão vegetal produzindo em fazendas da Vallourec unidade Florestal, distribuídas em quatro regionais no estado de Minas Gerais. O novo formato da operação permitiu a redução da frota utilizada e o aumento da taxa de ocupação dos equipamentos. Atualmente movimenta-se aproximadamente 400.000 ton./ano de carvão vegetal. A frota é composta por equipamentos novos, rastreados, transportadores dedicados, os quais são considerados parceiros no desenvolvimento da operação. Avalia-se o desempenho de cada equipe envolvida em frequentes reuniões, nas quais são definidas ações de melhoria sempre que necessárias. Temos um atendimento maior que 98 % a grade programada para recebimento do carvão vegetal, considerando os tempos de carga e descarga.

Jul 29, 2018

By D Macdougall, J Otto

The financing of large mining projects in developing countries is often achieved, at least in part, by limited-recourse financing methods. Financing agreements are affected by the basic accord that is struck between the host government and the sponsors of the project. It is concluded that governments and project sponsors should take into account the requirements of lenders when structuring such mineral development agreements to maximise the potential for attracting project financing. Lenders are likely to be most interested in aspects such as fiscal arrangements, calculation of taxable income and general accounting rules, royalties, transferability of payments/dividends overseas, corporate structure and control, staged development, financing, loan support and state guarantees/approvals, political risk, provisions for default, product marketing, settlement of disputes and environmental issues

Aug 1, 1994

By Bruna Brito Freitas

O processo de soldagem por fricção é uma técnica recente que vem sendo desenvolvida a fim de melhorar a qualidade das estruturas offshore. Com a finalidade de aperfeiçoar essa técnica é importante estudar as propriedades metalúrgicas do material soldado. Este trabalho tem como objetivo avaliar a tenacidade ao impacto de um aço C-Mn soldado por fricção com pino consumível, conhecido como FHPP (Friction Hydro Pillar Process). Desta forma, no presente estudo o material foi soldado, tratado termicamente, e após avaliado através de análises metalográficas, de microdurezas e ensaios de impacto Charpy. Como resultados foram geradas microestruturas para as diferentes regiões da solda e foram obtidos valores de energia, segundo a norma ASTM E-23. Por fim, conclui-se que o material não processado apresentou uma tenacidade superior a região de interface soldada, devido as diferentes microestruturas geradas no processo.

Aug 16, 2017

By R. Heuberger

South Africa?s Mining Industry operates in an uncertain world. The industry is buffeted by problems regarding retrenchments, unemployment, low productivity, rising costs, volatile exchange rates, commodity prices and government regulations. With these uncertainties facing the decision makers, what does applied technology offer the industry?s management? Modelling languages with risk analysis have been available for decades, but in the past their use has been very expensive, requiring large mainframe computers and lots of computer time. Today, PCs and laptops have incredible power, which makes interactive risk analysis affordable and viable for all enterprises, whether small or large. ?What is risk analysis? ?What is Monte Carlo simulation? ?What kinds of computer models need to be created to use risk analysis and Monte Carlo simulation effectively? This paper addresses these questions and illustrates, with a practical example in the mining industry, how risk analysis techniques can be used to support decisions in the climate of uncertainty.

Jan 1, 2005

By Érico França

A CBMM aplicou aços microligados ao nióbio de alta resistência mecânica para a fabricação de containers de caminhões que transportam grãos na região do Triângulo Mineiro e Alto Paranaíba, com o objetivo de reduzir o peso desses equipamentos e possibilitar o aumento da carga útil transportada. O novo projeto reduziu em 10% o peso do container e também aumentou seu volume útil de 27 m3 para 29 m3. O investimento teve retorno com apenas 8 dias de operação com o novo projeto transportando arroz. Também foram obtidos ganhos no transporte de milho e soja com o retorno do investimento em 21 e 56 dias de trabalho respectivamente. O trabalho mostra os aços utilizados e as principais alterações nos projetos desses componentes.

Aug 16, 2017

By Luciano Gianizeli Rodrigues

Este trabalho estuda a obtenção da fase S livre de precipitados, a partir da nitretação a plasma de pós de aço inoxidável austenítico 316, e analisa a variação do parâmetro de rede (aS) em função das diferentes condições de tempo e temperatura de tratamento. Os pós com granulometria entre 38 e 54 ?m foram nitretados em reator a plasma pulsado DC, sob atmosferas de 80%N2 e 20%H2, pressões de 400 Pa, por tempos de 1 a 9 h, e temperaturas de 420, 450 e 470ºC. Os resultados mostram que para a temperatura de 420ºC o parâmetro de rede (aS) aumenta continuamente com o tempo de tratamento, atingindo a máxima expansão (8,5%). Com o aumento da temperatura e do tempo de tratamento, verificou-se um recuo em aS associado à perda de nitrogênio e conseqüente formação de nitretos. É possível obter na temperatura 420ºC após 9 h cerca de 37% de fase S livre de precipitados, o que mostra a necessidade de realização de experimentos adicionais ou do desenvolvimento de métodos de separação das partículas nitretadas das não nitretadas.

Aug 8, 2018

By Thiago Figueiredo Azevedo

Ligas de titânio e nióbio têm sido desenvolvidas devido a possibilidade de modificar as propriedades mecânicas por envelhecimento. No presente estudo ligas TiNb com diferentes concentrações de Nb e com adição de estanho foram obtidas por fusão a vácuo, deformadas a frio e posteriormente tratadas por diferentes tempos de envelhecimento. Foi observado que todas as ligas em todas as condições apresentam as mesmas fases ß, a” e ?, no entanto, apresentam diferentes microestruturas. Isso se refletiu nas propriedades mecânicas das ligas, onde obtevese maiores durezas com o envelhecimento em 48 horas em todas as ligas, esse aumento de dureza foi quase o dobro para as ligas com maiores teores de nióbio (Ti42Nb e Ti42Nb2Sn).

Aug 16, 2017