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By Jadson Barbosa

Corpos de prova de ferro com diferentes níveis de pureza – um de pureza ultraelevada, dois de pureza elevada e um puro comercial – foram testados mecanicamente com diferentes taxas de deformação no âmbito de um antigo projeto. O objetivo era obter a resistência à tração de cada material e verificar a influência das impurezas e da taxa de deformação nas propriedades mecânicas do ferro de pureza ultraelevada. Para melhor compreender os resultados desses ensaios de tração, uma caracterização microscópica detalhada dessas amostras é realizada através deste trabalho. Para tal, foram analisadas as superfícies lateral e de fratura dos corpos de prova de tração no estereomicroscópio e no Microscópio Eletrônico de Varredura (MEV). O dano foi analisado em seções longitudinais ao longo do eixo de tração utilizando o microscópio óptico; a estrutura dos grãos deformados foi investigada por meio da técnica de microscopia EBSD (Difração de elétrons retroespalhados). Microestrutura, padrão de deformação, orientação dos grãos e as características das superfícies lateral e de fratura são então comparadas quanto ao processo de fabricação, nível de pureza e taxa de deformação.

Aug 17, 2017

By R. M. Rowe, T. E. Irwin

A flowsheet was developed for upgrading Climax tin concentrate to about 45 percent Sn. Bench-scale test work conducted at AMAX Extractive Research and Development, Inc., was used to design a multiple-stage tin- processing flowsheet which included screening, high-intensity magnetic separation, and high- tension (electric- static) separation. Formal engineering and plant installation was accomplished in-house by Climax mill personnel. The successful start-up operation of the facility was the joint effort of the AMAX R&D and Climax-mill staffs.

Jan 1, 1986

By Yoshihiko Maeda

It is said that the 21 st century will be an era of the remedy of the global environment. In order to reserve natural resources for the future and to avoid the dispersion of heavy metals after usage and to avoid pollution problems, it is extremely important to recycle heavy metals as much as possible by reasonable recovery procedures. The nonferrous metal industry is expected to play a important role in the recycling of heavy metals that are originally their products. From the depressed metal price experienced in Japan in 1980th due to the sudden change in current exchange rate between US dollar and Japanese yen, one of major nonferrous metal company, Dowa Mining, has diversified its business area not only to the so-called down stream, but also to the environmental business including metal recycling, industrial waste treatment and soil remediation by utilizing technologies and facilities once used or still used for mining and smelting of copper, zinc, lead and precious metals. In this paper some of these applications will be presented.

Jan 1, 2003

By Lloyd B. Underwood

Dr. Gardener, in Chapter 2, has presented a comprehensive state-of-the- art review of site investigations For tunneling. Nearly all of the techniques he discussed will also be required for future site investigations. Therefore, this chapter will be devoted to a few rather new exploration techniques plus ideas for improving some of the present-day methods. In March 1962, the first symposium on "Remote Sensing of Environment" was held at the University of Michigan.l Since that time, four additional symposiums have been held at the same University. Also, the technical Literature has recently included a number of articles on remote sensing techniques. A recent one appeared in the February 1968 issue of Materials Research and Standards.Vt was entitled "Developments in Remote Sensing Applicable to Airborne Engineering Surveys of Soils and Rocks," and was written by Dana C. Parker. Mr. Parker predicts that aerial reconnaissance will someday supplant soil augers, rock drills, surface reconnaissance, and geophysical surveys as the engineer's primary means of obtaining information about soils and rocks. He states, "The engineer wishing to survey a route or a site or to locate rock and soils suitable for construction projects will be able to push some buttons in an airplane and record all the data required for determining the relevant conditions. In a short time after he returns to earth with his rolls of film and charts, he will be able to reduce and analyze the data by partially computerized techniques and to compile a concise and comprehensive engineering report that gives all the relevant information about rocks, soil, water, and vegetation in the area he surveyed. Most important he will feel as confident with his recommendations, derived primarily from image characteristics and spectral power distributions, as his predecessors did with recommendations based on more tangible evidence obtained from drill cores and surface reconnaissance." The airborne sensors for engineering surveys of soils and rocks are those that sample some electromagnetic property of the materials that com- prise the terrain and cover its surface. In addition to cameras, these include

Jan 1, 1970

By Evelyn Dayrell Lopes Júnior

A capacidade de alimentação de sistemas de fundição é uma das características tecnológicas que está correlacionada a resultados qualitativos negativos, como porosidades e deformações geométricas dos produtos fundidos. As ligas com suas características são parte fundamental do processo de alimentação. A metodologia de caracterização da capacidade de alimentação por meio da coquilha Tatur foi utilizada nesse trabalho, para a qual foram desenvolvidos novos processos de dosagem da liga líquida, com o objetivo de prover maior repetitividade, e consequentemente, maior coerência morfológica das amostras produzidas. Para isso, foram desenvolvidos dois novos métodos de dosagem, chamados “método de dosagem dinâmica” e “método de pré-dosagem”. Esses foram testados e analisados, sendo suas amostras avaliadas comparativamente com o padrão morfológico teórico. O objetivo da obtenção de amostras coerentes foi atingido, sendo evidenciadas a grande influência das variáveis presentes na etapa de vazamento sobre os resultados das amostras obtidas.

Aug 17, 2017

By Ricardo dos Santos Oliveira

Devido ao grande aumento da concentração de gases do efeito estufa, a criação de uma energia limpa tem sido um desafio para a ciência e as indústrias. Após identificar possíveis soluções para este problema uma alternativa seria a utilização de biomassa vegetal com capacidade térmica como fonte energética redutora no processo de redução do minério de ferro em altos-fornos. Este trabalho teve como objetivo utilizar capim elefante (Pennisetum purpureum) e carvão mineral na injeção de finos pulverizados pelas ventaneiras de altos-fornos nas siderúrgicas a fim de reduzir custos da produção de ferro gusa e reduzir a dependência de combustíveis fósseis no processo. O capim elefante é uma fonte renovável e de rápido crescimento que através da fotossíntese captura o CO2 da atmosfera, reduzindo a poluição causada pelos altos-fornos. Para simular a injeção dos materiais estudados foi construído na Escola de Minas - UFOP um modelo de partículas de combustão para analisar as amostras. Outras técnicas são utilizadas para caracterização como combustão, calorimetria, análise de gás, análise química imediata e elementar. Assim, em teoria, esta pesquisa mostra que o capim elefante misturado com carvão mineral através de sua injeção em altos-fornos mostrou-se viável em termos metalúrgicos e ambientais.

Aug 17, 2017

By David G. Adam

Syncrude Canada Ltd. is currently mining over 120 million tons per year of overburden and oil sands to produce 40 million barrels per year of synthetic crude oil. Production increases are planned. This paper reviews the technical and economic assessments of feeder breaker applications in both ore and waste mining which led to an extensive testing and development program and finally to the procurement of full scale production equipment.

Jan 1, 1985

By Paola Campana, Maurizio Lenzi

"In the paper a non linear model for the analysis of the pile response to the axial loads is presented. The study aims to find a general analytical solution concerning the pile-soil interaction modeled by means of the method of the load transfer curves. It makes use of a criterion based on the plastic and on the hardening work locally done by the shear stresses and due to the current elastic shortening of the shaft. Then a specific solution, denoted fractal model, is found applying recurrent relations that link the shaft shear stresses and the tip normal stresses to the pile settlements. These relations are based on that one proposed by Kondner in modeling the soil samples response in the triaxial tests and then used by Chin in the inverse slope method in estimating the pile capacity by the load test results. The comparison between the model predictions and the load tests measures validate the fractal model.INTRODUCTIONThe behavior of the axially loaded piles is known to be characterized by a highly non linear trend caused by the onset of plastic and irreversible deformations in the soil starting just from the first load levels. With the purpose to reach a deeper understanding of the pile-soil interaction, the influence of the soil inelastic properties on the distribution of the axial loads and of the vertical displacements is investigated. The research starts analyzing the behavior of an infinitesimal length of a pile embedded in a non linear homogeneous soil. That initial study leads to a criterion based on the plastic and on the hardening work locally done by the shear stresses and that allows to find the axial loads as a function of the elastic shortenings of the shaft. The relation that links the pile axial load to the elastic strain of the pile material is then used. That allows to find the vertical displacements and the axial loads as function of the depth in a parametric form in which the tip settlement acts as an independent parameter. The method of the load transfer curves is used and the effects of the pile technology are included in the soil constitutive relations. The analysis is then extended to the non-homogenous soils in a very effective way. The solution is applied taking as constitutive relations of the pile-soil interface the one proposed by Kondner to analyze the soil triaxial tests and by Chin to interpolate the pile response measured in the load tests."

Jan 1, 2017

By V. A. Marple, K. L. Rubow, Y. Tao

"A personal diesel exhaust aerosol sampler has been designed and evaluated in both laboratory and field settings. The sampler uses size selective sampling for the determination of the respirable mass concentrations of mineral dust and diesel exhaust particulate matter found in underground coal mines. This design is based on the premise that diesel exhaust particulate matter is predominantly less than 0.8 um while mineral dust is greater than 0.8 gm. Operating at a flow rate of 2 L/min, the sampler consists of a 10 mm Dorr-Oliver respirable dust cyclone followed by an 0.8 gm cutpoint impactor and an afterfilter. Field evaluations consisted of sampling at 6 different locations in these underground coal mines. Measured aerosol concentration less than and greater than 0.8 um have been compared with a well characterized cascade impactor.Techniques must be developed for measuring the mass concentration of diesel exhaust particulate matter found in underground coal mines due to the health concerns associated with worker exposure to diesel exhaust particulate matter. Diesel exhaust particles are in the respirable size range and have been regarded as a potential occupational carcinogen by NIOSH (1988). Furthermore, a 1988 MSHA advisory committee directed MSHA to develop a sampling protocol for assessing worker exposure to diesel exhaust particles.The University of Minnesota and the Bureau of Mines, over the past 4 years have measured the size distribution of diesel exhaust particles and mineral dust, both in the laboratory and underground mines (Cantrell, 1987; Cantrell et al., 1987; Cantrell and Rubow. 1988; Marple et al, 1986; Rubow et al., 1988: and Watts et al., 1989). To date, measurements have been made in nine coal mines. Seven mines utilized diesel-powered equipment at the mine face while two used electric-powered equipment. The results of these field tests indicate that mineral dust and diesel exhaust particles can be differentiated on the basis of particle size. The measured particle size distributions have been found to be bimodal with a saddle point at 0.8 um. This has led to the hypothesis that one method for measuring worker exposure to diesel exhaust particles would be to collect size fractionated particle samples separated at 0.8 um with the diesel particles being less than 0.8 um and the mineral dust particles greater than 0.8 um.Aerosol size distribution measurements, using a micro-orifice uniform deposit impactor (MOUDI), have been conducted in the mine intake air portal, intake entry to the working section, haulageway, and section return entry. The MOUDI is a ten stage cascade impactor with particle cutpoints ranging from 0.1 to 15 um aerodynamic diameter (Marple and Rubow. 1984b; Marple et al., 1989). The sampling flow rate is 30 L/min."

Mar 1, 1992

By Everaldo Afonso Fernandes

O presente trabalho foi realizado com a finalidade de estudar o efeito dos elementos titânio (teor de 0,05%) e de níquel (teor de 0,03%) na liga Al-0,05%Cu-[0,24-0,28] %Fe-0,7%Si para fins de transmissão e distribuição de energia elétrica. Dessa forma, foi adotada uma sequência operacional a fim de caracterizar as estruturas apresentadas pelas ligas. Os processos de solidificação foram realizados via coquilha de aço (forma de “U”). Depois de solidificadas as ligas, os lingotes passaram pelos processos mecânicos de usinagem e laminação para obtenção de corpos de prova com quatro distintos diâmetros (2,7; 3,0; 3,8; 4,0) mm a fim de aproximar estes das bitolas utilizadas em indústrias de cabos elétricos. Todas as ligas foram caracterizadas macroestruturalmente analisando as estruturas brutas de fusão, eletromecanicamente por meio do ensaio de tração [?] e condutividade elétrica [%IACS]. Posteriormente, para a melhor compreensão dos resultados foram avaliados os valores de alongamento [?%] indicando que o diâmetro 3,00mm é a modificação com 0,05%Ti foram os de melhor resultados apresentados.

Aug 7, 2018

By J. G. Walters

Analyses of light oils produced from the fluidized carbonization of coal at 485°, 550°, 600°, and 660° C are presented. Tar vapors from 485 C fluidized carbonization were thermally treated at 600°, 700°, and .800° C, and the analyses of light oils produced by this treatment are also presented. Procedures were developed for analysis of coal carbonization light oil by gas chromatography to permit a more definitive analysis than can be obtained by the conventional distillation procedure. An increase in low-boiling olefins, benzene, and toluene, a decrease in low-boiling paraffins, and little change in the remainder of the aromatics was observed with increased temperature of carbonization.

Jan 1, 1965

By Ayumi Yoshioka

Os componentes automotivos em geral devem atender a especificações rigorosas de propriedades mecânicas, requisitos de limpeza inclusionária, entre outros. Enxofre e alumínio são dois elementos adicionados ao banho líquido, que têm papel importante na obtenção destas propriedades, mas que dificultam o processo de produção por lingotamento contínuo por favorecer a formação de partículas sólidas de alto ponto de fusão, que podem prejudicar a limpeza inclusionária e provocar a obstrução das válvulas de lingotamento. O objetivo do presente trabalho é analisar e classificar as inclusões de corridas do aço DIN 38MnSiVS6 em escala industrial e avaliar estes resultados em conjunto com os dados de processo de aciaria e com os resultados de simulação termodinâmica utilizando o software FactSage 6.4. Foi observado que as corridas apresentaram tanto sulfetos de cálcio quanto espinélios, mas as primeiras, associadas a uma fração líquida menor na escória, tiveram uma correlação mais perceptível com a má lingotabilidade.

Aug 17, 2017

The Hail Creek coking coal deposits are situated in Central Queensland, inland from the port of Mackay. A joint venture of Australian and Japanese companies has been formed to examine the feasibility of developing these deposits for sale on the overseas markets. The project envisaged involves large scale mining operations and on site benefic- iation to wash the coal to marketable quality. Infrastructure items include a 140 kilometre railway to the coast, a port facility, and at Ilail Creek, power and water supplies, roads and communications, and accommodation for a substantial workforce. The need for town development and the responsibility for the development are established. The town planning implications of coal production at the rate of five million long tons of washed coal per annum from open cut and underground mines are considered. A procedure for estimating the size of the town is expounded and the town size is determined. The factors influencing site selection are explained and a site is suggested. A method of designing the town is described and comments are made on developmental aspects. Spaciousness and preservation featuring the natural environment will be the theme of the town development.

Jan 1, 1973

By E. B. Nelson, B. W. Gandrud, B. M. Bird

"The Lewisburg No. 2 mine of the Sloss-Sheffield Steel & Iron Company is located in Jefferson County, Alabama, about 7 miles due north of Birmingham. At this point the coal from the Mary Lee seam when coked in by-product ovens yields an excellent quality of metallurgical coke suitable for use in the iron blast furnace; it is also an excellent steam coal. In mining, all three benches are worked. Coarse impurities are largely gobbed by the miners underground.In addition to giving the data obtained from screen-sizing and float-and-sink tests of a representative sample of the raw coal, this report presents the results of slotted-screen tests to show the proportions of flaky particles in selected sizes, and the results of tests to show how much coal is liberated from impurities by crushing the coarsest sizes. These data have been obtained in connection with an extensive study of coal-washing now being conducted by the U. S. Bureau of Mines and the University of Alabama, with U. cooperation of the different operators of Alabama. As the work progresses other reports will follow containing furtner data on the washability both of the Mary Lee seam and of other seams in Alabama and giving the results obtained in preparing these coals by various methods.Although a great amount of investigative work on the preparation of the Mary Lee scam was previously carried on by the various coal companies of the district, comparatively little of this information has been published. In governmental publications three references have been found. Forbes5 gives a number of sections with proximate and ultimate analyses of face samples taken in the mines. Gandrud and Britton'' show sections of this seam at Flat Creek and New Castle; they also give the specific gravity and ash contents of the partings of coal and impurities. In their paper Yancey and Fraser7 include washability studies and washing data from the Sayreton mine of the Republic Iron & Steel Co."

Jun 1, 1930

By F. D. Aaring

"IntroductionTHE PINCHER CREEK gas condensate field, in Township 3, Range 28, and Townships 3 and 4, Range 29, West of the Fourth Meridian, was discovered in 1947 by the Canadian Gulf Oil Company with the completion of Pincher Creek No. 1 well in the Madison lime-stone of Mississippian age.This discovery was the result of a great deal of detailed seismic work in the area and is a credit to the geophysical personnel of the Company. The depth of the reservoir varies from 7,400 feet to 8,200 feet subsea, with the established water level at -8,200 feet. The predicted depth was but a scant 100 feet from that found in the discovery well, at 11, 705 feet. Since the discovery of the reservoir, three additional wells have penetrated the Madison limestone and have further verified the original •seismic interpretation of the limits of this reservoir.To date, •only a very small amount of gas has been produced from this field. Consequently, the reservoir studies that have been made so far are predominantly based on investigations of the phase behaviour of the fluid and physical characteristics of the reservoir rock. In view of the above limitations, it has been necessary to set up and perform model reservoir studies with the fluids and to recover as much core from the productive Madison limestone as possible in order that it might be analysed by conventional laboratory technique and be subjected to detailed microscopic geological examination."

Jan 1, 1952

By A. Hutwalker, T. Plett

"Blast fumes are one of the major sources for NOx in underground mines. In 2016, the Occupational Exposure Limits for NOx in Germany were reduced by 90%. The task is to keep re-entry times after blasting at the present level and thereby ensure an economic operation of the mine. Measurements show that using ventilation solely is not sufficient. A new approach to reduce NOx from blast fumes is described. Laboratory experiments were performed and a reduction of NOx was observed. Measurements were conducted at an explosive factory’s testing facility and in an underground mine at blasting operations. INTRODUCTION Whether for production of ore or for drift development, the processes in an underground mine are always the same: 1) fracturing the rock, 2) loading the pile, 3) support the resulting cavity. The fracturing of the rock can be done mechanically, by cutting, for example by using continuous miners or tunnel boring machines, or by drilling and blasting. Drilling and blasting is more flexible than mechanical driving, as it can be used independently of the rock strength. Furthermore, this driving method allows a more flexible reaction to changes in geological and/or operational conditions. Thus, underground mining and blasting are almost inextricably linked with each other, and regardless of the size and level of technology of the mine, blasting is hardly avoidable. Depending on the mining method chosen and the existing framework conditions, such as the mechanical properties of the rock or the availability of machinery, blasting is an integral part of daily operations. Even in mines where blasting is not part of regular operations, it cannot be completely avoided. The blast fumes generated by the explosions are, in addition to diesel engine emissions, one of the two main sources of emissions of nitrous gases underground. Up to now, state of the art for dealing with blast fumes is ventilation. The fumes are diluted with fresh air and ventilated out of the mine. This treatment of blast fumes is more than sufficient with the former German Occupational Exposure Limits (OEL). The adaption of the OEL in Germany to the recommendations of the Committee on Occupational Exposure Limits (SCOEL), a committee of the European Commission, leads to big challenges for the mining industry in reducing the concentrations of these gases at the workplaces underground. On its meeting on May 2nd and 3rd 2016, the Committee on Hazardous Substances (Ausschuss für Gefahrstoffe, AGS), an advisory body of the German Federal Ministry of Labour and Social Affairs (BMAS), advised the BMAS to copy the OEL, as recommended by the SCOEL, to the Technical Rules for Hazardous Substances (TRGS 900). BMAS followed this advice, consequently the new OEL where published on November 4th 2016 and became part of the TRGS 900. Table 1 shows the former and new OEL for Germany. These new OEL became law after publishing, but two exceptions were made: For tunneling operations, they became law on October 31st 2017, for mining operations they will become law on October 31st 2021 (BAuA, 2004, 2016, 2017)."

Jan 1, 2019

By Artur Camposo Pereira

O presente trabalho buscou explorar a aplicação da ultramicrodureza instrumentada na caracterização microestrutural e mecânica de materiais metálicos aço inoxidável 304L e liga NiTi Rica em Ni, ambos no campo austenítico. Para isso foi utilizado um ultramicrodurômetro instrumentado (Shimadzu, modelo DUH–211S) com medidas a temperatura ambiente e distintas cargas máximas e tempos de permanência. De acordo com algumas das possibilidades apresentadas, pode-se concluir que a ultramicrodureza instrumentada é uma ferramenta poderosa para a caracterização mecânica correlacionada aos aspectos microestruturais de materiais metálicos.

Aug 17, 2017

By M. Phylli Bray

"Concurrent with the continuing demise of many Canadian mining towns is the rise of a new method of providing remote mine sites with a workforce. This is the Long Distance Commute (LDC) which uses commuter labour and requires no permanent settlements to support the mine operation. It provides a flexible and cost effective method of operation to the industry and relieves both governments and industry of the expense of building and maintaining mining towns. However, little attention has been paid to the effect on workers or their families of the LDC work schedule whereby workers spend a fixed number of days at the site followed by a fixed number of days at home. Off-shore oil rig experience would indicate that negative social impacts may be expected. Research leading to an understanding of the problems involved seems to be indicated. One innovative suggestion has been to use already established but dying mining towns as workforce pick-up points for new LDC operations further north.BackgroundUntil recently, mine towns were considered as a necessary component of mine development. This was a natural symbiosis resulting from the need to provide workforce accommodation close to isolated mine sites. The early mine communities in Canada were often just a huddle of shacks around a head frame. Gradually mining companies began to provide housing which varied from basic duplexes and quads in grid pattern layout to professionally planned and designed towns, either model company towns or the more recent suburbs-in-the-bush, the so-called ""instant towns"" of the postWorld War II era of resource development. The improvement in accommodation reflected the need to attract a stable workforce as mine operations became more sophisticated. City amenities were expected and offered in these mine towns as a way of encouraging a permanent community of mining families. Indeed in towns like Manitouwdage, Schefferville, and others, it was not unusual to find a significant percentage of two- and three-generation families apparently providing the permanent mining communities so desired by mine operators."

Jan 1, 1991

By Joseph W. Richards

ALTHOUGH bad grammar, the above query is probably, at the present moment, good sense. Why was the Institute started and why does it continue to exist? The small group of men who worked out the original idea felt keenly the necessity of mining engineers and metallurgists getting together in order to discuss their professional problems. That necessity still exists but it does not strike the present generation of engineers so keenly because they have always had the Institute: they do not know what it is to be without it. The Institute is a great graduate school of mining and metallurgy. All of its members who have something to say worth saying are the teachers; all the rest may be learners or critics. No university or technical school can match the experience and information which the authors of its papers possess, no institution of learning has a body of potential listeners so extensive and so vitally interested.

Jan 1, 1921

By Marco Vinicio Guamán Alarcón

O modelo do Gradiente de Tensão (SG) e a Teoria da Distância Crítica (TCD) são usados para estimar o limite de fadiga de corpos de prova com entalhes alongados, e essas estimativas são testadas em C(T) modificados submetidos a tensões cíclicas de amplitude constante com uma razão de tensão R = 0.1. Os valores medidos são comparados com as previsões feitas por ambos os modelos. As previsões do modelo SG estiveram mais de acordo com os resultados experimentais. Também foi demonstrado que o modelo SG é quase equivalente à TCD no caso de entalhes com raios grandes, quando a TCD usa o método do ponto. Para o caso de entalhes afiados, os valores dos limites de fadiga previstos pela TCD são mais conservativos que os previstos pelo modelo SG.

Aug 17, 2017