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By Eduardo Gomes Vieira

O Projeto 4ª Pelotização surgiu com o propósito de aumentar a capacidade de produção de pelotas da Samarco em 37%, por meio da implantação do 3º Mineroduto, com capacidade de 20 Mt/ano, a 4ª Usina de Pelotização com capacidade de 8,25 Mt/ano e o 3º Concentrador com capacidade de 9,5Mt/ano. O projeto proposto visa estruturar o processo de Manutenção do Concentrador 3 através do sistema de gestão de dados utilizado pela Samarco Mineração, o software SAP, com foco na criação de um modelo taxonômico de níveis hierárquicos contendo informações técnicas dos novos equipamentos e respectivos sobressalentes, dando base para definição de uma política de estoque, a implementação de planos de manutenção e estudos de confiabilidade. Objetiva a redução do Risco Operacional, consolidando no sistema os processos que compõem a função manutenção, referente à terceira Usina de Beneficiamento de Minério de Ferro da Samarco Mineração. Para isto, foi utilizada a metodologia Kaizen para estruturação e desenvolvimento do trabalho e estabelecimento de metas para controle das informações. Verificou-se uma grande demanda de avaliação de criticidade e cadastro dos equipamentos e sobressalentes, além disto, a falta de organização das informações de forma estruturada poderia acarretar dificuldades de se analisar itens faltantes. Foi necessário também o estabelecimento de critérios para implementação de planos de manutenção visando à preservação da integridade e funcionalidade dos equipamentos.

Aug 16, 2017

By B. Valentim

Policies for reducing NOx emissions have led power plants to restrict O2, resulting in high-carbon fly ash production. Therefore, some potentially useful fly ash, such as the economizer fly ash, is discarded without a thorough knowledge of its composition. In order to characterize this type of fly ash, samples were collected from the economizer of a Portuguese power plant burning two low-sulfur bituminous coals. Characterization was also performed on economizer fly ash subsamples after wet sieving, density and magnetic separation. Analysis included atomic absorption spectroscopy, loss-on-ignition, scanning electron microscopy/energy-dispersive X-ray spectroscopy, optical microscopy, and micro-Raman spectroscopy. Key words: Fly ash; Petrology; Petrography; Economizer fly ash

Jan 1, 2009

By James J. Olson

Most of the projects summarized in this paper are funded under the Bureau's Advancing Metal-Nonmetal Mining Technology program and are part of the in situ mining subprogram coordinated at the Twin Cities Mining Research Center. The borehole mining equipment development, are funded under the Bureau's Advancing Coal Mining Technology program, is essential to accelerated progress in the in situ mining subprogram, and some background information on this concept is included. The initial in situ research projects started in 1971-72 evaluated some of the critical blast design parameters for in situ copper leaching. The present program totals about $1 million per year and includes in-house research projects, cooperative (cost-sharing) projects with the mining industry, and research and development contracts. Two different extraction schemes are under investigation: inplace leaching and borehole (or slurry) mining. The principal commodity targets for the Bureau's improved in situ mining technologies include copper, uranium, coal, and potash. The principal purpose of this paper is to inform the mining industry of the in situ mining research recently completed or being conducted by the Bureau of Mines. In addition the Bureau encourages companies to comment on the program accomplishments as well as offer suggestions on top priority research needs for improving the in situ mining methods described in this paper.

Jan 1, 1977

By D. L. Morgan, J. A. Butterfield

"Geological data, production trends and current projects underway suggest that enough molybdenum will be available from more diversified sources to meet the world's growing demands. The growth in molybdenum consumption has been primarily related to its beneficial effects as an alloying agent in steel. This rapid growth has been deliberately fostered by stable prices, adequate supply and application research. The molybdenum industry is now in a process of change which has been seen in several other metals, such as aluminum and nickel. As supply sources have become more diversified, the market has become more competitive. The recent drop in consumption has led to excess production capacity, accumulation of substantial producer inventories and increased market uncertainties. While consumption is expected to increase in the next two to three years, it will take some time to absorb the excess capacity and inventory. The increased proportion of by-product capacity indicates that prices may become more variable. Producer discipline will be required to prevent serious price erosion in times of surplus. Future prices may not continue to increase with inflation. For the longer term, several factors favour the increased consumption of molybdenum. Engineering requirements are becoming more severe and molybdenum alloys can help to meet these changing needs. In addition, consumers can rely on a large and increasing supply of molybdenum. A 7 per cent growth rate in consumption can probably be sustained through the next decade, but new applications and reasonably stable prices will be needed to make this possible."

Jan 1, 1972

By Tailoka F.

Various metallurgical residues from iron and steel making processes have been treated by chlorination in excess air with hydrogen chloride gas generated from the combustion of scrap polyvinyl chloride (PVC). The residues include dust from both the electric arc and blast &maces, hydrocyclone overflow, zinc - lead blast furnace slags and dust rich in zinc and copper from copper refining. Chlorination is achieved either directly by mixing the residues with scrap PVC or indirectly in a two furnace system. In the latter, scrap PVC is combusted between 523 and 573 K in a horizontal furnace and the resulting gases are then reacted with metallurgical residues in a vertical furnace at 1166 to 1329 K. Gas chromatography, thermogravimetric measurements, XRD and AAS have been utilised to study the reactions. The recovery of non ferrous metals is as high as 80 to 90 % and only a negligible amount of iron is carried over. The optimum temperature for combustion is between 518 and 573 K. Above 600 K, the evolution of HCI is so fast that sufficient chlorination is not achieved. Analysis showed that no dioxins were present in the gases, the residues or the chlorides.

Jan 1, 1997

By Marcos Campos Silveira

A Unidade Niquelândia da Votorantim Metais possui 9 fornos multi andares usados para a redução de minérios lateríticos com o uso de monóxido de carbono e hidrogênio como agentes redutores. Cada forno possui 10 câmaras de combustão para geração destes gases que trabalham em contra-corrente com o minério alimentado pelo topo do forno. Já utilizado como combustível óleo A2 incorporado ao minério bem como sua combustão em câmaras. O trabalho consiste na substituição do óleo por uma emulsão de combustíveis líquidos e sólidos a fim de flexibilizar a matriz energética e promover redução do cash cost sem queda na eficiência operacional. A utilização industrial da emulsão teve início em 2006 através da sua incorporação ao minério alimentado na proporção de 19% de coque de petróleo e 81% de óleo A2 em poder calorífico e em 2014 esta mistura alcançou a proporção de 39% de coque e 61% de óleo A1. Em paralelo e após testes de combustão em planta piloto, foram realizados testes industriais de queima também nas câmaras de combustão em dezembro de 2012. Com o bom desempenho, em dezembro de 2013, 14 das 90 câmaras já estavam nesta condição com previsão de 20 câmaras até junho de 2014 otimizando a capacidade da estação de óleo+coque. Com isto a substituição (%) global dos fornos em poder calorífico avançou de 6,38% em 2011 para 16,12% em 2014 acumulados até abril. Com uma nova estação existe a possibilidade de operar 90 câmaras nesta condição e chegar a um valor de 39% de substituição global.

Jul 31, 2018

By Miguel Gutiérrez

This paper will seek to provide an awareness of the challenges the permitting process presents to the engineering design for open pit mining projects in Perú. This awareness will create a better understanding of the permitting process within the several groups in mining companies that are responsible for getting the mine project started or continue its operations.

Sep 21, 2013

By Shiwei Wang, Ziwen Li, Chenhu Zhang, Peng Chen, Chengyong Wang

Accurate prediction of the partition coefficients in coal gravity separation is key to improving the preparation efficiency of coal and promoting its clean utilization. In China, the approximate formula method (AFM) has been applied to the calculation of coal gravity separation partition coefficients for decades, but its accuracy is limited. To improve the accuracy of the predicted partition coefficients, and thus the product yield of coal preparation plants, the present study proposes a modified hyperbolic tangent model to derive direct calculation formulas for the heavy medium and water medium separation partition coefficients. Four groups of coal samples were used to verify the accuracy of the direct formulas, and their predictions were compared with those of the AFM. The results showed that the partition coefficients and partition curves predicted by the direct formulas were closer to the actual values than those predicted by the AFM. Further, when the cleaned coal ash content was basically the same, the cleaned coal yield predicted by the direct formula was lower than that predicted by the AFM, and was also closer to the actual value. These results demonstrate that the direct formula produces more accurate results compared to the conventional AFM. As this formula has a reasonable theoretical basis, is simple to apply, and produces accurate results, it is expected to help improve the design and management level of coal preparation plants.

Oct 15, 2022

By N. Dhawan

With ever-increasing demand, low-grade complex ores and strict environmental regulations, metallurgical processing options have become limited. Heap leach technology provides several benefits to combat these issues including low cost, flexibility and diversified process conditions. This paper provides an overview of heap leaching technology with specific emphasis on chemical aspects. Hence, influencing factors, advantages and disadvantages, testing approaches and some fundamentals will be discussed. Finally, heap leach technology for different ore types (copper, nickel, uranium and gold) will be briefly compared.

Jan 1, 2012

By Karla Carolina Alves da Silva

Esse trabalho tem por objetivo, propor a utilização de um dispositivo, criado na UFPE, para estudar a fadiga funcional e mecânica num atuador de Ti-Ni com memória de forma. Inicialmente, fios de Ti-Ni com efeito memória de forma, com 0,89 mm de diâmetro, foram submetidos a um tratamento térmico de homogeneização por 24 horas a temperatura de 500ºC e têmpera em água a 25ºC. Posteriormente, os mesmos foram submetidas a calorimetria diferencial de varredura para obtenção das temperaturas de transformação. De posse desses dados, foram confeccionados atuadores com a forma de mola helicoidal. Utilizando o dispositivo proposto, esses atuadores foram submetidos às deformações cíclicas, com expansão total de 10mm, num banho térmico programável, a temperatura constante de 85ºC, na condição supereslástica, essa etapa é denominada neste trabalho de ciclo rápido. Com o objetivo de analisar o efeito dessas deformações cíclicas sobre as temperaturas de transformação e a capacidade de recuperação de forma dos atuadores foi realizada um segunda etapa, aqui denominada de ciclo lento. Nessa etapa, os atuadores foram solicitados à esforços de tração equivalentes a tensão de cisalhamento no fio de 70 MPa, dentro do intervalo de temperatura entre 15°C e 85°C, e tiveram o deslocamento e as temperaturas de transformação monitorados por um sensor LVDT e por um termopar respectivamente. Os ciclos rápidos e lentos são intercalados periodicamente. Dessa forma, observou-se a influência da ciclagem termomecânica na degradação do efeito de memória de forma.

Aug 16, 2017

By A. G. Roach

Introduction The plant described in this paper is located at Coniston, Ontario, the smelting centre of the former Mond Nickel Company. Coniston is situated some eight miles east of Sudbury on the main line of the Canadian Pacific railway and on the Toronto-Capreol branch of the Canadian National-railways. The plant is now under control of the International Nickel Company, as a result of the merger of the two companies in 1929. The smelter proper includes four 50-in. by 240-in. blast furnaces and five 13 ft. by 30 ft. converters, and has a capacity of about 65,000 tons of ore charge per month. As accessories to the smelter there are a mill, where some 10,000 tons per month of low-grade ores are concentrated, and the sintering plant, which is the subject of this paper. The present 6-unit sintering plant replaces a former 4-unit installation. Here, fine ores, concentrates, and flue-dust are sintered on Dwight-Lloyd machines, the sinter produced being charged into the blast furnaces. At the time of writing (1931), only the concentrator is operating at capacity, due to present world conditions.

Jan 1, 1932

By John Marsden, Mike Botz

A variety of modeling techniques can be utilized to forecast metal production at heap leaching operations. These approaches reflect a wide range of complexity, flexibility, time to implement, cost, and accuracy. For many operators, a spreadsheet-based modeling technique is attractive since the calculations are directly accessible, models can often be developed by site staff, and the results are generally easy to extract and interpret. The authors have developed a spreadsheet-based modeling technique that provides a high degree of flexibility, while still considering detailed operating information for ore properties, leach kinetics, scaleup factors, lift height, and in-heap metal inventories. The technique involves establishing kinetic leach curves for each ore type to characterize metal extractions, followed by application of separate metal recovery curves to define the rate at which leached metals exit the heap in pregnant solution, taking into account delays due to the in-heap solution inventory. At any point in time, the difference between total metal extracted and total metal recovered is equal to the in-heap inventory of the leached metal. This modeling technique is particularly useful for larger multi-lift heaps where delays in metal recovery are appreciable due to in-heap solution holdup. The technique is also applicable to sites with multiple heaps, leach cycles, and/or metal recovery plants (e.g., carbon columns for gold; solvent extraction for copper). This paper describes the modeling technique, including input data required and methods for defining kinetic leach curves and metal recovery curves. The technique is compared against an alternative spreadsheet technique using a simplified in-heap solution inventory calculation to forecast metal production, which has proven to be effective at a number of sites.

Sep 3, 2019

By Hugh S. Spence

IN MAY, 1930, G. LaBine and E. C. St. Paul, prospect¬ing round the southeastern shore of Great Bear Lake, in the North West Territories of Canada, discovered pitchblende at what is now LaBine Point. At the same time, they also found native silver in a small sheared break on an island lying off the point. Late in 1930, samples of the pitchblende were sent to the Mines Branch, at Ottawa. The material consisted of several fair-sized slabs of botryoidal pitchblende banded with a brownish quartz. A small amount of chalcopyrite was visible as small particles and fine veinlets, and the pieces were rather heavily stained a yellowish-green by secondary copper-uranium salts. Analyses were run in the Mines Branch Ore Dressing Laboratories on two samples, and small-scale concentration tests were made on one of them. The results of this work were published in a Memorandum Series report (No. 48) of the Mines Branch, in March, 1931.

Jan 1, 1932

By A. V. Yevdokimov, Ye. V. Bogorodsky

The paper presents the results of the research on the development of gravity concentrates processing technology (gold grade is from 50 g/t to 1 kg/t and over) using intensive cyanidation with gold recovery to pregnant solutions followed by precipitation of metals from them using various methods. Test work and pilot plant results confirm that a new developed hydrodynamic regime provides an efficient treatment of gravity concentrates of polydisperse composition without their grinding and preliminary desliming. The resulting pregnant and washing solutions are amenable to metals recovery using electrowinning, cementation onto zinc dust and CIS. Cone plants with a lower ball valve for cyanidation of unground gravity concentrates developed by IRGIREDMET JSC have been successfully tested at a number of Russian operations. Currently, a modular plant equipped with gold electric precipitation from pregnant solution unit is successfully operated at a Russian gold processing plant. Cyanidation of the resulting high-grade gravity concentrate is carried out at the concentration of 8-10 g/L NaCN and 10 g/L NaOH. Gold recovery to the solution is 97-98%. Electrowinning is carried out in flow cell GNC-40M. In this case, the residual gold concentration yield is 0.3-0.5 mg/L. Also, a modular plant for relatively low-grade middlings (50-100 g/t Au) of gravity concentration has been introduced. The concentration of NaCN and NaOH is 2-3 g/L and 1.5-2 g/L, respectively, during leaching. This plant is equipped with a unit for gold cementation from pregnant solution with zinc dust. This cementation unit is of original design. It is made in the form of a filtering device and is composed of several layers of carbon fiber which contacts with zinc powder. The residual gold concentration yield from a cementation unit is less than 0.1 mg/L. Gold recovery is 93-97%. In 2017-2018, the introduction of intensive cyanidation modular plants to gravity concentrates will be planned at new projects of Russia and the CIS.

Jan 1, 2018

By William Gleason

"Sluggish prices for commodities and a glut of oversupply of many commodities did not stop the world’s largest mining equipment makers from showing off their latest and greatest machines and technology starting with the world’s largest equipment trade show, bauma 2016 in Munich, Germany.From April 8-14, an estimated 580,000 visitors from 200 countries visited the show that featured 3,423 exhibitors from 58 countries. While primarily a show for construction equipment, the mining footprint has grown over the years. Among the largest exhibits was that of Liebherr, which brought more than 100 products, had an outdoor exhibition stand, a stand for the components division and a career stand under the motto “Be Part of Something Bigger.” One of the biggest aspects of the exhibit was its mining products where the company staged the first-ever professional table tennis match in the 130 m3 (170 cu yd) dump body of the T 264 mining truck. The top German players Timo Boll and Patrick Franziska with their trainer Jörg Robkopf faced Austria’s singles world champion from 2003, Werner Schlager, and the reigning Team Europe champions Chen Weixing and Stefan Fegerl.“Bauma 2016 was an absolute success for Liebherr. With this year’s appearance we were once again able to show our innovative strength, performance and technological diversity to a very large and international audience from the industry. We conducted interesting discussions with numerous customers and partners from various countries and discussed new projects,” said Stefan Heissler, Member of the board of directors of the Liebherr Group.Likewise, Caterpillar, the world’s largest maker of construction and mining equipment had a large presence at the show with more than 60 products and 12,000 m2 (129,000 sq ft)of exhibit space. Among the iconic yellow mining equipment that was on display was the 6015B hydraulic mining shovel."

Jun 1, 2016

By V. D. Jalevsky

A new methodology of an experimental-analytical approach has been developed. It is used in building an information geomechanic monitoring system for the modeling of geomechanic processes during coal seam working. The approach synthesizes experimental (in-situ) measurements of rock pressure manifestation in separate points, methods of numerical modeling of processes on rock boundaries with coal, and a seam analytical calculation of rock mass in a spatial strained state. One of the realizations of this approach is the developed theory and calculation method of adjoining rock surface shift (overhang) formation during underground working of sheet deposits and of rock mass geomechanic state determination. There are description algorithms of cavity configurations with broken lengths of faces during underground working of useful mineral sheet deposits. These algorithms have been used in computer modeling of formations of adjoining rock surface overhangs and abutment pressure upon rock mass in the area of coal faces with irrectilinear longwalls. Peculiarities of surfaces shifts and stress allocation are established for different face schemes. The use of theory and methods alloww working out techniques of automatic control to receive processing algorithms of RPM measurement results and calculate geomechanic situations within panels in the process of planning and development as well as during mining, i.e., to carry out long-term prediction, in-line control, and short-term prediction of rock pressure manifestations.

Jan 1, 1996

By R. D. Brittain

In order to analyze and control the transport of harmful trace-element impurities in various smelting processes, it is necessary to have fundamental information about the chemical thermodynamic properties of the pertinent condensed and vapor phases. This paper describes recent thermodynamic studies of the gaseous arsenic sulfides and of the activity of arsenic in a copper-iron sulfide matte phase. These studies were carried out by high temperature mass spectrometry and by effusion vaporization techniques, which permitted clear identification of the molecular species involved, a decided advantage in such complex systems. The nature of the results obtained and comparisons with previous interpretations will be described.

Jan 1, 1983

By Elione Moura Carlos

O objetivo principal deste trabalho foi incorporar o resíduo de mármore no desenvolvimento de formulações de massas cerâmicas para obtenção de grês porcelanato. Foram preparadas quatro formulações da massa cerâmica variando-se as proporções de caulim, talco, feldspato, argila de queima clara e do resíduo de mármore nas misturas. Essas matérias-primas foram peneiradas na malha 200 mesh e as porcentagens para cada formulação foi misturada em moinho de bolas por 30 min. Os corpos de prova foram preparados em uma prensa uniaxial com pressão de 25 MPa e sinterizados em forno convencional nas temperaturas de 800°C, 900°C e 1.000°C, com patamar de 60 minutos e taxa de aquecimento de 10°C por minuto, verificando as propriedades das peças. Para obtenção de resultados foram realizados ensaios de absorção de água, retração linear nas peças sinterizadas, massa específica aparente e porosidade aparente, com o propósito de avaliar a variação de retração linear em determinada temperatura de acordo com a porcentagem de absorção de água. Foram realizados também os ensaios de flexão e microscopia eletrônica de varredura - (MEV). As composições estudadas apresentaram resultados satisfatórios dentro dos valores aceitáveis para o devido uso na indústria cerâmica.

Aug 7, 2018

By V. F. Parry

This report is the first substantial description of the carbonizing process and the details of experimental work conducted at the Denver laboratories under a coopeative agreement between the Bureau of Mines and the Texas Power & Light Co. It presents the results of tests on several Texas lignites and other typical western coals that have been processed in the first pilot plant operated at Denver. Investigations on drying fine coal in the entrained and fluidized state have been under way at Bureau of Mines Denver laboratories for several years. Reports on this work were published in 1949 and 19505/ describing the theory and practice of re-moving inherent moisture from the lower -rank coals. The investigation did not include a study of the removal of surface moisture from fine fuel. Private industry in Canada became interested in the possibilities of drying fine coal, employing the closed-circuit system and techniques recommended by the Bureau. Large, commercial-scale drying units were built by a Canadian company, which successfully demonstrated that surface moisture could be removed from fine coal at high efficiency and capacity ill drying units similar in design to those developed by the Bureau.

Jan 1, 1953

By H. A. Watson

Laboratory tests on three commercial methane detectors, two combustion- type detectors and one interferometer-type detector, were made by the Bureau of Mines to determine their response to certain single and multiple flammable gases mixed with normal and abnormal air atmospheres. Although both types of detectors responded accurately to methane-normal air mixtures, they did not show correct concentrations for other single flammable gases in air. Uniquely, the response of the interferometer-type detector to hydrogen was in a negative direction. The effects of individual gases in multiple flammable gas mixtures were approximately additive. In oxygen-deficient atmospheres the methane response of the interferometer-type detector erred on the high side, but only in very low oxygen concentrations were the combustion-type detectors affected-- showing low, erratic methane readings.

Jan 1, 1966