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By Edward E. Johnson

The Bureau of 'Mines publishes in its ?Minerals Yearbook? a series of indexes on the domestic minerals industry. Among these are the index of physical volume of mineral production, indexes of stocks, and indexes of average unit mine value and implicit unit value, This report describes the material coverage of these indexes and the methods used in their construction. Detailed descriptions are given for several other mineral-oriented indexes regularly published by other government agencies. These descriptions give the index user a better understanding of what each index purports to measure and aids him in selecting the most appropriate index for his purpose.

Jan 1, 1965

By M. D. Carver

This publication describes development by the Bureau of Mines of a quality evaluation procedure for certifying the adequacy of production lots of Kroll process zirconium sponge the Bureau had produced for reactor applications. After the procedure was devised, the next step was to apply it in controlling the quality of one-half million pounds of zirconium sponge com-prising 259 production lots, called blends, originating at the Metallurgy Research Center of the Bureau at Albany, Oreg. The Bureau concluded that the evaluation method developed was adequate and that by this method the zirconium blends having impurity levels or other property values outside specification limits were differentiated and thus were diverted from nuclear energy end uses. The research was performed under contract for the Bureau of Ships, Department of the Navy, and for the Atomic Energy Commission (AEC).

Jan 1, 1960

By John E. Conley

The great demand for metallic aluminum for the prosecution of World War II caused the consumption of bauxite, the common ore of aluminum, to increase greatly. Prior to the war, the domestic deposits 'of bauxite, which occur chiefly in Arkansas and less extensively in Georgia, Alabama, and Mississippi, supplied only: about 30 ,percent of the ore required for aluminum-metal production and approximately 40 percent of alumina for all purposes. Enemy activities during the war seriously interfered with shipment of bauxite from the normal peacetime source in Surinam, Netherlands Guiana, South America, and focused attention on the necessity for increasing production from known domestic deposits. Even in peacetime, the production of aluminum ore in the United States could not satisfy requirements. Field drilling and exploration by Bureau of Mines engineers resulted in the discovery of important tonnages of high-grade bauxite suitable for treatment by the conventional Bayer process, Although an ore containing approximately 55 percent Al2O3 and only 2 to 4 percent SiO2 is preferable, it was necessary to use ores containing up to 8 or 10 percent SiO2. Because of the lower recoveries of aluminum with increased silica content, the Reconstruction Finance Corporation, through the Metals Reserve Company, established a base price of $4 for a 50-percent Al2O3 ore, containing 13-percent silica, with a premium or penalty of 14 cents for each percent of Al2O3 over or under 50; each percent of SiO2 under 13 was awarded a 20-cent premium, and each percent over 13 suffered a penalty of 43 cents; all prices were on the basis of 1 long ton of ore, dry basis.

Jan 1, 1949

By Robinson Reis Miranda

Este trabalho discute o desenvolvimento de massas de tamponamento de furos de corrida de fornos de redução: altos-fornos, fornos de ferros-ligas, cubilôs, entre outros, a partir de resíduos de chamote, materiais refratários, alumina e piche de alcatrão, subproduto da coqueria, utilizado como aglomerante. Foram investigadas as condições de plasticidade, resistência, usinabilidade, moldabilidade e poder de adesão. Os resultados obtidos mostram a possibilidade de emprego industrial destas massas de tamponamento.

Aug 7, 2018

By Pedro Damas Resende

As propriedades físicas e mecânicas de ligas NiTi são fortemente influenciadas pelo seu histórico termomecânico. Este trabalho visa avaliar a influência de uma deformação preliminar (chegando ao escorregamento da martensita) aliada ao recozimento de uma liga NiTi sobre suas propriedades através de DSC (Calorimetria Diferencial Exploratória), ensaios de tração até a ruptura e difração de raios X (DRX). Observou-se um aumento da histerese térmica como resultados dos tratamentos, e as transformações martensíticas passaram a ocorrer com formação de fase intermediária (fase R) para os grupos recozidos. Os valores de tensões de início e fim de patamar do grupo tratado diminuíram em relação ao grupo do material como recebido.

Aug 16, 2017

By Marcos Fernando Campioto Junior

O objetivo deste trabalho é apresentar os resultados obtidos, após a implantação da ferramenta de otimização do planejamento e programação da produção CScheduler Weekly Planner da PSI Metals na ArcelorMittal Tubarão. A ferramenta de otimização CScheduler permite realizar o planejamento e programação de médio prazo para as máquinas de lingotamento contínuo da ArcelorMittal Tubarão, visando melhor atendimento as regras de negócio relacionadas a cliente, redução custos operacionais e redução de instabilidade operacional do processo. Este trabalho também apresenta a criação de um novo Modus Operandi para o planejamento e programação com resultados obtidos em casos de testes e resultados pós-implantação em produção.

Oct 30, 2017

By Giovanna Lorena Carneiro Costa, Ana Paula Silva, Amarildo Ferreira, Vinícius Freitas Paixão

Uma maneira de detectar macro inclusões é através de testes ultrassônicos, embora a análise e a interpretação dos resultados dos testes sejam difíceis de entender. Com os resultados da inspeção, temos informações sobre a localização das macro inclusões e, portanto, sua distribuição ao longo do material. No entanto, estabelecer critérios para classificar o material quanto à sua pureza tem sido uma tarefa difícil. O presente trabalho visa estabelecer uma ferramenta de análise de dados a ser utilizada para controle de qualidade de materiais. Os resultados mostram uma viabilidade estatística e metalúrgica de aplicar este modelo analítico para avaliar o nível de pureza dos aços laminados a quente.

Mar 1, 2019

By Roberto Abreu Alencar

Com o barateamento dos custos de implantação e inovações em estruturas geradoras de energias renováveis, nos dias atuais a demanda de instalação de fontes renováveis de energia tem aumentado exponencialmente. Porém como toda estrutura estas estruturas estão condicionadas a falhas de vários tipos. Neste trabalho apresenta-se uma análise de falha de uma peça, de uma estrutura de sustentação de um aerogerador de pequeno porte voltado a micro geração de energia. Para a condução da análise da falha foram realizados analises microscópicas, fractografias, análises macrograficas e modelagem em elementos finitos. Assim as causas das falhas foram identificadas, como má escolha de materiais e alguns erros no projeto da peça.

Oct 30, 2017

By Ricardo Miranda Alé

Aços resistentes ao serviço ácido (sour service), com requisitos adicionais de alta resistência mecânica e tenacidade, têm sido especificados para aplicação em gasodutos do Pólo Pré-sal da Bacia de Santos. O desenvolvimento de aços que atendam a estes severos requisitos, visando à fabricação de tubos de elevada espessura, constitui um enorme desafio para o fabricante do aço. No presente trabalho, é apresentado o desenvolvimento do aço API 5L-X65 Sour Service para esse tipo de aplicação, onde são descritas as principais ações realizadas no processo de produção que permitiram o sucesso no desenvolvimento do produto, confirmado pelas excelentes propriedades obtidas nas chapas e nos tubos.

Aug 8, 2018

By R. F. Stewart

A key step in changing coals to fluid fuels and chemicals is the conversion of coal to synthesis gas by gasification with steam and oxygen. As oxygen represents one of the largest single expenses in gasification, its cost is a vital factor in the economy of the process. At present, the most economical method for producing tonnage oxygen is by the conventional rectification of liquefied air. Several alternate methods have been proposed for producing oxygen from air: (1) methods based on physical or chemical sorption of oxygen from air by liquids or solids or (2) the oxidation of certain inorganic com-pounds to higher oxides unstable at higher temperature levels. Economic limitations are discussed by which these methods may be evaluated. Chelated metals of the salcomine type are promising chemical sorbents of oxygen from air. This report covers a study of the reversible sorption of oxygen by salcomine and other chelates. The presence of water in the salcomine structure was verified; it is the loss of this water that causes slow deterioration of salcomine during cycling.

Jan 1, 1959

By A. L. Peyton

Manganese-oxide minerals occur in irregular pockets distributed through the residual clays of the Cartersville district, which lies 45 miles north-west of Atlanta in Bartow County, Ga. The district produces, or has produced, limonite, barite, specular hematite, ochre, ferruginous manganese, manganiferous iron are, as well as manganese. Bureau of Mines engineers have visited the district on three occasions - in December 1939, February 1941, and October 1942. During the visit of February 1941, 80 tons of samples of manganese-bearing clays were taken from seven properties for ore-dressing tests, which were conducted at the Bureau of Mines laboratory at Rolla, Mo. The. October 1942 visit was for the purpose of reappraising the district in the light of knowledge gained from the ore-dressing studies and to prepare a plan for the district's development. Exploratory drilling was begun in March l943 and was continued until June 1945. Nine properties were explored that, roughly follow a line beginning near Cartersville and extend to a point 2 miles northeast of the village of White. The work consisted of bulldozer trenching, rotary bucket churn drilling, sampling, and analytical determinations. The manganese district is 18 miles long with a maximum width of 7 miles at Cartersville, which lies at the center of the district. The work of the Bureau was confined to the northern half of the district between Cartersville and Pine Log. The properties explored comprise but a small portion of the Potential producing area.

Jan 1, 1949

By Eduardo de Paula Silveira, Carlos Vinícius Domingos de Carvalho, Roberto Parreiras Tavares, André Afonso Nascimento, Honicássio de Souza Ferreira, Afrânio Márcio Costa

Modelos de transferência de calor possibilitam o conhecimento de espessura da camada solidificada e temperatura da placa, essenciais para alterações no processo visando melhoria de qualidade. Neste estudo foi desenvolvido um modelo pelo método 2½ D, que consiste em acompanhar em toda extensão da máquina uma secção transversal da placa, ajustando as condições de contorno para cada região. Medições de temperaturas superficiais e de espessura da camada de aço solidificada da placa foram utilizadas para validação do modelo. O modelo foi adequado para as condições de contorno e parâmetros da máquina de lingotamento contínuo de placas da Gerdau Ouro Branco visando fornecer subsídios para a melhoria da qualidade superficial e interna das placas.

Oct 1, 2019

By J D. McDonald

This paper outlines the function of the Safety and Compensation Division of the Mining Association of British Columbia. After a general discussion of safety and the safety program now being followed in B.C., the author goes on to describe the wide-ranging aspects of compensation payments and company assessment rates. Special attention is also given to the problem of silicosis in mining operations. In appendices to the paper, the experience rating plan of the mining industry is compared to that recently adopted for the construction industry. Introduction The Mining Association of British Columbia consists of fifty-five member companies, including virtually all the producing mines as well as the larger exploration, contracting and development companies. On completion of an extensive study of safety and compensation in the mining industry, the Mining Association of British Columbia instituted a Safety and Compensation Division in 1954. The director of the Safety and Compensation Division reports to the Executive Committee of the Association. There are two main functions of this Division. First is the prevenion of accidents by encouraging

Jan 1, 1965

By T. R. Carter, A. C. Colvine

"Rocks of the Grenville Province in southeastern Ontario are currently largely dismissed by many geologists as having little or no potential for discovery of significant deposits of metallic minerals. The present study demonstrates that the area contains numerous deposit types which elsewhere are major metal producers. Therefore, there is significant unrealized potential, especially for gold, zinc, uranium, and possibly copper.The variety of deposits of metallic mineralization include stratiform zinc in marbles; stratabound base metal sulphides in volcanic and sedimentary hosts; gold-quartz veins; quartzmagnetite iron formation; copper-nickel and iron-titanium in intrusive rocks; magnetite skarns; molybdenum in skarns and pegmatites; uranium and thorium in pegmatites, veins, and calc-silicate gneisses; hematite veins; dolomite marbles (magnesium); and barite-jluorite-celestite-galena-calcite veins. There has been significant production of iron, lead, zinc, magnesium, gold, silver, and uranium.The vast majority of the metallic mineral deposits are confined to late Precambrian supracrustal and related intrusive rocks of the Grenville Supergroup. Many of the deposits are stratiform and/or stratabound and occur within units toward the top of major volcanic successions and in the lower portions of younger carbonate-clastic sedimentary successions.Processes responsible for mineral concentration in the area include: (I) syngenetic hydrothermal activity related to both volcanism and sedimentation; (2) epigenetic processes related to diagenesis, regional metamorphism, and igneous intrusive activity; (3) magmatic processes related to igneous intrusions; and (4) supergene concentration and enrichment. The genetic classification of the mineral deposits presented is based on observed geological relationships and these interpreted geneses. The deposit types have counterparts in volcanogenic and sedimentary exhalative, Mississippi Valley type, magmatic, contact metasomatic, and lode gold deposits. Many of the exploration criteria for deposits of these types may be applicable in the Grenville Province, despite the generally high metamorphic grades and complex deformation."

Jan 1, 1985

By L. I. Rosato

A novel hydrometallurgical process for the recovery of silver and gold from neutral leach residue that is based upon leaching with thiourea, is described. Laboratory and pilot plant studies have shown that 80-90% of the silver and 60-70% of the gold can be recovered by:? ( i) leaching zinc calcine with 'Spent electrolyte at pH 2.0-3.0 to generate a precious metal-bearing zinc ferrite residue, (ii) leaching of the thickened zinc ferrite with 3-5 g/L thiourea in a six stage carbon-in-pulp circuit, (iii) elution of silver and gold from the loaded carbon with a thiourea- butanol solution, (iv) thermal regeneration of the stripped carbon and (v) recovery of the precious metals from the pregnant eluate by cementation with zinc dust. The reasons for adopting the thiourea CIP leach and the preferred operating parameters for each process step are presented. The requirements for the destruction of any thiourea transferred to the zinc circuit are outlined, and the results of an integrated one tonne/day pilot plant operation at Canadian Electrolytic Zinc are given.

Jan 1, 1990

By M. Gonçalves Peixoto da Silva, E. Rodrigo Carvalho Souza Siqueira

Mining in narrow veins is commonly applied for precious metals, generally carried out to extract gold in underground mines, due to the ore occurrence on narrow veins, mainly up to 2-meter large. The current work presents the implementation of the methodology in a zinc mine located in the state of Minas Gerais in Brazil. The Vazante Mine through the years has always carried out mining on stopes with a thickness larger than 3,5 meters, but nowadays due to the need to reduce the waste planned in its blocks, as well as increase the useful life of mine, mining has been implemented in blocks that are less than two meters. Given this, the challenge is to be able to carry out blasts that does not exceed the operational dilution required and does not generate an impact on recovery, as working with extremely heterogeneous stopes. This study seeks to correlate the main characteristics of stopes and its relationship with the results obtained in the execution of those blasts. Also, it proposes an analysis between the empirical data, and existing theoretical references, creating ideal mining parameters, such as minimum thickness, maximum height, and optimum timing in the blast plan. One of the main challenges for carrying out this mining method is the control of operational dilution, generally pointed out as the biggest difficulty for companies that adopt this methodology, due to the thickness of those stopes, any displacement can make it unfeasible, thus the technical level on carrying out the drilling and loading of these blocks must be impeccable, an understanding of the structural geology of the site is also essential for dilution control. The outcome will be a set of ideal parameters and mining methodology to guarantee the success in execution of these blocks, thus bringing a financial benefit to the company.

Jan 21, 2025

By Thamiris Auxiliadora Gonçalves Martins, Karen Espina Gomes, Amilton Barbosa Botelho Junior

The present work aims at the synthesis of nanoparticles of copper by chemical reduction in microwave oven. The solution used comes from the selective copper precipitation of the lateritic nickel leachate. The copper solution (20mL) was placed in a beaker, and 2mL of 100g/L ascorbic acid and 20mL of 20g/L sodium citrate were added in that order and at room temperature. The pH of the mixture was corrected with 1M sulfuric acid or 2M sodium hydroxide. Then the mixture was placed in a microwave oven. The effect of pH, time and microwave power were evaluated. The morphology, composition and size of the particles were verified in Scanning Electron Microscopy with Energy Dispersion Spectroscopy (SEM/EDS). Results showed that the particles formed had no nanometric size. This may have occurred because the reducing action of ascorbic acid together with sodium citrate generates a very rapid reduction rate, which makes it impossible to form particles on a gauge scale. Particles synthesized at pH 4, after 4 minutes of reaction with 1000W of power presented particles with spherical morphology and only copper in the composition.

Oct 3, 2019

By Robert A. Clifton

This Bureau of Mines report discusses the mineralogy of zeolites, the properties that make them commercially valuable, the conditions of formation of both natural and synthetic zeolites, and present and potential markets.

Jan 1, 1987

By Izabelle Lannes Salgueiro Ferreira

O presente trabalho teve como objetivo adequar às propriedades mecânicas dos perfis ASTM A572 G60, através do estudo da influência dos parâmetros de processo de laminação e composição química do aço. Os perfis ASTM A572 G60, são utilizados nas indústrias de fabricação de torres de transmissão. A metodologia utilizada neste trabalho foi o desenvolvimento de um modelamento matemático, com base na ferramenta estatística de Análise de Regressão Múltipla. Através desta ferramenta foi possível obter previsibilidade de processo e identificar os parâmetros mais influentes nas propriedades mecânicas dos perfis ASTM A572 G60, o que possibilitou a determinação da composição química ideal do aço e os melhores parâmetros de processo de laminação.

Jul 30, 2018

By Willy Ank de Morais

Para se determinar as propriedades mecânicas de uma junta soldada torna-se necessário conhecer as propriedades mecânicas do metal de adição decorrente de um processo de soldagem. O objetivo desse trabalho foi verificar as propriedades mecânicas de uma solda MAG elaborando e qualificando um procedimento de soldagem. Para isso foi utilizado quatro ensaios mecânicos: tração, macrográfia, micrografia e dureza. Foi estipulado o limite de escoamento, de ruptura, o alongamento e a estricção; macrográfico, determinou-se, a olho nu, a zona fundida, a zona de ligação, a zona termicamente afetada e o metal de base; micrográfico, tração, definiu-se os componentes microestruturais da solda e do metal de base; dureza e foi estabelecida a tenacidade da solda e do metal de base.

Aug 16, 2017