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By Brian F. Taylor

The Mexican fluorspar industry is faced with and will face serious problems, some of their own making and others beyond their control. However, they still offer the most secure source of fluorspar for North American' consumers. Since 1975, even in light of declining markets, they have, increased then production capabilities' as shown in Table #1. In analyzing Table #1, we note that Compania Miners Rio Colorado has closed down due to their ore reserves being exhausted. Fluorita de Rio Verde expanded their acid grade fluorspar capacity in anticipation of additional North American business. Campania Miners Las Cuevas presumably increased capacity to meet their North American contractual commitments and to supply their own hydrofluoric acid plant (Fluorex) at Juarez, Mexico. Historically, the Mexican fluorspar industry has relied on the United States as the mainstay for their sales. As shown in Tables #2 and #3, the Mexican share of the United States market has moderately decreased. However, as noted in Table #4 the volume loss is substantial as explained below.

Jan 1, 1985

By Guilherme Bougleux Michelin Assunção

O projeto visa o estudo da reatividade e da resistência do coque, combustível tradicionalmente utilizado na siderurgia, relacionando às diversas condições presentes no alto-forno. Para a realização da pesquisa, foram utilizadas amostras de coque de uma empresa siderúrgica nacional. O coque foi analisado através dos ensaios Coke Reactivity Index (CRI) e Coke Strength After Reaction (CSR) no Laboratório de Processos Metalúrgicos da Universidade Federal de Minas Gerais (UFMG). Os testes foram realizados em tempos e temperaturas pré-determinados para simular as diversas zonas percorridas durante a descida do termo-redutor nos altos-fornos. Os resultados mostraram a viabilidade termodinâmica da gaseificação do coque a partir de 900°C, sendo possível calcular a energia de ativação da reação de Boudouard a 1100°C, e a correlação entre CRI e CSR coque.

Aug 17, 2017

By Marcella Mateus de Mello

O presente trabalho objetiva analisar a influência da distribuição de intensidade espacial do laser na geração de padrões de speckle em superfícies metálicas. Os padrões de speckle estudados são obtidos quando o laser atinge uma superfície metálica. A análise da imagem de padrões de speckle pode ser relacionada com a rugosidade de superfícies metálicas iluminadas com o laser. Com esse estudo pretendemos melhorar a sensibilidade das medidas de rugosidade de superfícies metálicas a partir das imagens de padrões de speckle.

Aug 17, 2017

By James R. Hindman

Vermiculite is the mineralogical name generally applied to a group of hydrated, trioctahedral ferromagnesian aluminum platty or micaceous silicate minerals. In microscopic particles the mineral as mineral is differentiated from montmorillonite by a higher Si:AI ratio of approximately 3:l and a higher layer charge and higher cation exchange capacities. Commercial vermiculite, the vermiculite which is mined, beneficiated, and discussed in this chapter, is an important industrial mineral which is formed by the alteration of macroscopic particles of biotite and iron-bearing phlogopite. In natural form it has the size and shape of mica, while possessing the ion exchangeable properties of zeolites and some clays. Within the internal structure of vermiculite lie water molecules, which when rapidly heated to high temperature, transform into steam causing the vermiculite particles to increase in volume. This process of thermal exfoliation produces a lightweight product which finds use in various construction products, agriculture, horticulture, and other industrial applications. In exfoliated form it has the low density and biological inertness of expanded perlite, while maintaining a chemically active surface. Most of the uses of vermiculite are for the thermally exfoliated material. In addition, the cation exchange potential of vermiculite and its layer-silicate structure are properties which can be used as the basis for numerous products including intumescent coatings and gaskets, inorganic films, and the treatment of nuclear and other toxic waste. When chemically and physically modified, it possesses some properties common to organoclays and synthetic compounds. In high purity concentrates and manufactured products, these properties can be altered and optimized in applications to produce superior performance. GEOLOGY Mineralogy Vermiculite was first described as a mineral by Thomas H. Webb in 1824. Webb believed vermiculite to be a variety of talc and described its diagnostic property of thermal exfoliation thusly: "If subjected to the flame of a blowpipe, or that of a common lamp, it expands and shoots out into a variety of fanciful forms, resembling most generally small worms having the vermicular motion exact." Observing that with one exception, all commercial vermiculite has formed by the alteration of iron-bearing phlogopite, a simple definition of vermiculite might be the alteration product of trioctahedral micas, macroscopic particles of which display marked exfoliation when heated rapidly to temperatures above 374°C (the critical temperature of water). The first vermiculite described was found near Worcester, MA, but it was later pointed out by Brush (1866) that vermiculite had been known for some time in Japan as a children's novelty. Because the techniques for mineral analysis were somewhat primitive com- pared to those routinely available today, and because the structure and crystal chemistry of the micas and related minerals were not widely understood, the early literature generated at least 20 "new" minerals which were nothing more than variations in the color and chemistry displayed by vermiculite. Trade names such as Dugarlite, Mandolitem, Strong-LiteTM, and Zonolitem are sometimes used to denote commercial vermiculite, thermally exfoliated vermiculite and their products. Vermiculite particles resemble mica and vary in color from colorless through tan and green to black, depending on the chemical composition. Most physical and optical properties are close to those of biotite, with perfect basal cleavage, hardness between 1.5 and 2.5 Mohs, and specific gravity between 2.2 to 2.8. Fine-sized particles will feel talcose, especially when wet. However, for commercial vermiculite the diagnostic test is that of thermal exfoliation. Vermiculite can display a wide range of compositions, depending on the composition of the original mica and the change of chemistry during weathering and ion exchange. Chemical data for some commercial vermiculites are given in [Table 1]. There are numerous analyses for vermiculite given in the literature, and the analyses of vermiculites from commercial deposits will fall within the range indicated by the average analysis in the table. Many analyses separate the adsorbed water (H2OP) from crystalline water and water as hydroxyl (H20+). The basis of separation of adsorbed water is generally considered to be 100°C. However, hydrate water within the vermiculite interlayer begins to be lost at 75°C and lower. Therefore, measured water content and loss on ignition are combined in the table as H20[total].

Jan 1, 1994

By A. G. Journel

Accurate prediction of recoverable reserves are key to the development and planning of a mining operation. Recovery functions for tonnage, quantity of metal and ore grade are defined and two approaches for their estimation are proposed. The indicator kriging (IK) approach draws on the data rank orders, whereas the multi-gaussian (MG) approach relies on a grade multi-variate distribution hypothesis. Although based on different premises, both approaches yield remarkably similar--and accurate--estimates for recoverable reserves.

Jan 1, 1984

By F. J. Hurst

Phosphate rock, which is a prime source of phosphate used in fertilizer manufacture in the United States, contains uranium. In general, the uranium content of the rock increases with the phosphate content and most high-grade phosphate deposits (>30% P2O5) contain 0.01- 0.02% U3 8. The large tonnages of rock being mined represent a significant potential source of uranium that lends itself to recovery as a by-product of the wet-process phosphate industry. For example, in 1953, the U. S. Geological Survey estimated that recoverable phosphate reserves in the U. S. totaled about 5 billion tons and contained 600,000 tons of uranium. I This estimate did not include any rock from North Carolina which has since been estimated at about 2 billion tons. For the most part, the known, economically mineable U. S. reserves - estimated at about 7 billion tons - are concentrated in a few areas: 43% in the western states of Idaho, Montana, Utah and Wyoming; 28% in each of Florida and North Carolina and less than 1% in Tennessee. In the past, Florida has supplied about 80% of the total U. S. production, practically all of which is land pebble phosphate. All forecasts indicate increased production rates from North Carolina and the western states.

Jan 1, 1976

By Paulo Roberto Gomes de Sousa

O trabalho mostra a analise de energia e exergia de uma unidade termoelétrica, esta planta consiste em um ciclo regenerativo. Serão comparados os nivéis de irreversibilidade dos componentes que compõem a unidade. A escolha do ciclo regenerativo com a referência em análise, é devido sua eficiência global. Isso é proporcionado através do aquecimento da água de alimentação da caldeira, com isso, consequentemente ocorre uma diminuição da necessidade de energia imposta na caldeira. A análise realizada também mostra as irreversibilidades da planta através da análise de exergia.

Aug 17, 2017

By David E. Nicholas

Design of underground openings is becoming more critical as the mine deposits become lower in grade, initial investments increase, ore depth increases, additional safety regulations come into law, and increased ore recovery is required for conservation of minerals. Stability of these openings is dependent on the strength of the rock mass and the pre-mine stress field. The rock mass is composed of solid blocks of rock (rock sub- stance) and structural features (faults, joints, bedding, etc.). Methods of testing the rock mass strength are improving and be- coming more common, however it is difficult to justify the high cost of large scale testing for an initial mine design. An alternative to testing the rock mass is to measure the rock substance and the structural features separately, and then combine them to estimate the rock mass strength. The rock mass strength will vary depending on the orientation of the opening with respect to the structural features. The other factor affecting the stability of underground open- ings is the pre-mine stress field. Methods are available to measure "directly" the pre-mine stress in competent and relatively massive rock. These methods are costly to employ, therefore, they may not be justified in an initial study. The pre-mine stress field can be estimated based on the structural relationships formed from past tectonic events.

Jan 1, 1976

By Johannes Münzer

Regeneradores são elementos importantes em uma usina siderúrgica. Eles são os responsáveis pelo aquecimento do ar de sopro aplicado no alto-forno a partir do aproveitamento da energia contida nos gases do processo de produção de ferro gusa. Dessa forma, os regeneradores estão diretamente associados ao processo siderúrgico. Durante do seu ciclo de trabalho, o qual se denomina campanha, problemas podem ocorrer devido a variações operacionais indesejadas, falhas de projeto, entre outros fatores. Num ambiente onde o tempo cessante de um equipamento gera enormes custos, a solução é desenvolver soluções customizadas que minimizem essa interrupção. Cada uma das partes do regenerador tem funções únicas e consequentemente soluções únicas, que visam o reparo no estado da arte com menor custo.

Aug 17, 2017

By Elifas Levi da Silva

O novo ambiente de competitividade, ocasionado pela globalização, impõe que as empresas tenham um compromisso ainda maior com a redução dos seus custos. As ineficiências não podem mais ser repassadas aos clientes. Na mineração um dos custos expressivos existentes refere-se aos pneus utilizados pelos equipamentos móveis. Baseado na representatividade dos custos dos pneus faz se necessário à aplicação de técnicas de mantenabilidade com a finalidade de aumentar a vida útil destes ativos, realizando as manutenções e monitoramentos necessários para maximização da sua performance, uma vez que o desempenho dos pneus existentes na mineração em estudo estavam menor do que o esperado. Partindo deste objetivo foi formado uma equipe de projeto com a finalidade de estudar os principais modos de falha dos pneus, podendo assim propor ações de melhorias no intuito de otimizar sua performance. Após a implantação destas ações observou-se uma melhora significativa nos indicadores de gestão dos pneus, levando a conclusão dos impactos positivos que o projeto trouxe a mineração.

Oct 30, 2017

By Rosiane Mary Rezende Faleiro

O carvão vegetal, CV, é o componente individual com maior impacto no custo final de uma usina integrada. Diante desta realidade, foi desenvolvido um processo de carbonização contínua, uma tecnologia moderna que a diferencia das carbonizações tradicionais, permitindo que o CV produzido tenha melhores características físicoquímicas. Sendo assim, o desafio agora é encontrar condições operacionais adequadas para produzir em larga escala a um custo competitivo. Com base nisso, desenvolveu-se este trabalho com o objetivo de avaliar o desempenho de um altoforno, em condições reais de operação e em escala industrial, utilizando dois tipos de carvões (CVs): CV Referência e CV produzido por carbonização contínua (Carboval). Os principais parâmetros operacionais foram monitorados. O CV Carboval apresentou melhores resultados para as análises químicas e granulométrica, melhor permeabilidade no alto-forno e menor consumo bruto, demonstrando sua viabilidade técnica.

Aug 17, 2017

By Qingwen Shi, Brijes Mishra

The abstract discusses the use of numerical simulations to investigate roof fall in underground mines. It highlights the advantages of the discrete element method (DEM) in simulating large strain problems and fracturing processes, while acknowledging its computational limitations for large-scale problems. The study presents a 3D numerical model coupling the finite difference method (FDM) and DEM to simulate laminated roof failure in a coal mine. The model represents the laminated roof with bonded particles and discontinuities, while the surrounding rock is represented by continuum zones. The research analyzes the fracturing of the laminated roof as the entry advances, demonstrating the coupled method's ability to reproduce laminated roof failure.

Mar 17, 2022

By J. A. Ruppert

The Bureau of Mines investigated methods of refining iron-contaminated zinc to marketable quality and developed a laboratory-scale process in which aluminum, added as a refining agent, reacted with the iron, forming solid Fe2Al which floated to the surface of the melt. Solids were separated by both filtration and centrifugation, using a unique type of "dipping" centrifuge devised during the work. Typical zinc recovery was 95 percent, and iron content of the metal was lowered from 0.37 to 0.02 percent.

Jan 1, 1967

"1 INTRODUCTIONThe use of nondestructive testing (NDT) methods to evaluate the integrity of Augered Cast-in-Place (ACIP) and Drilled Displacement (DD) piles has been a subject of significant debate among engineers, contractors and NDT practitioners. This guideline document will illustrate the importance of reviewing all available information in conjunction with the NDT records. ACIP and DD piles have unique properties that must be considered when using a specific NDT method. Any evaluation of the integrity of an ACIP or DD pile must also include a thorough review of the detailed pile installation records and the site specific soil conditions. Long or theoretical descriptions of the methods have not been included in this publication. More detailed information about these NDT methods including their theoretical and historical backgrounds can be found in DFI’s Manual for Non Destructive Testing and Evaluation of Drilled Shafts (2004). Additional information can also be found in the more comprehensive textbook Nondestructive Testing of Deep Foundations by Hertlein and Davis (2006).1.1 PurposeThe intent of this guideline is to provide practical guidance for the proper interpretation of NDT results on ACIP and DD piles. Short descriptions of the main integrity methods available are provided along with several examples of how to use all of the information available to make sound engineering judgments about the results. This publication is a state-of-the-practice guideline to promote accurate engineering evaluations.For engineers inexperienced with NDT, these guidelines provide sufficient background information on NDT methods to help understand the limitations of the testing, assess the results presented to them, and formulate appropriate questions. This is particularly important for engineers charged with the responsibility to determine from those results what, if any, consequences there may be on the performance of the structure under construction."

Jan 1, 2016

By Z. G. Tao, Y. Y. Peng, W. L. Gong, M. C. He

"This paper presents an overview of the major landslide hazards in open pit mines in China, the currently used landslide control and monitoring techniques, and development of a new slope control technique incorporating the reinforcement, sliding force monitoring, remote sensing and forecasting in one system in order to constrain the displacement of the sliding blocks in the landslide to minimized the influenced area and provide precise warnings timely for the imminent landslides. For implementation of the new technique, a novel rock cable with large deformation and high resistance (also known as HE cable) was developed, which can elongate as long as 2m. At the same time, the necessary and sufficient condition for initiating a landslide and energy balance equations are formulated. Based on the proposed mathematical models and Beidou satellite system, the software and data transmission hardware for remote sensing and forecasting were developed the new landslide control technique has been applied successfully in 245 landslide sites in 12 provinces across China. In this article, two practical application cases in the open pit mines are reported.INTRODUCTIONChina is one of the countries in the world with the most widely distributed landslides and suffering the heaviest damage. According to the incomplete statistics, landslide hazards have caused death of hundreds of people and direct economic losses of several hundred million RMB each year. The landslide hazards have a great impact on the life and property safety of the people, safety of the infrastructure, as well as the social stability. Thus development of new techniques for forecasting and prediction of the landslides is imperative and of great importance. In general, the forecasting and prediction of the landslides consists of three major aspects, i.e. sliding time forecasting, landslide activity intensity forecasting and landslide hazard degree forecasting. Since a considerable part of the landslide-suspected area are adjacent to the residential areas or important infrastructures, development of the advanced landslide control and monitoring techniques to cope with the sliding time forecasting problem is more important.Over the past one hundred years, the most widely used slope monitoring techniques are based on displacement monitoring (Xu, et al. 2007; Toshitaka, 1998). In the early days owing to the limitation of the technology and equipment, the ground surface displacement and underground water level change were inspected mainly by man power for inferring the possibility of a landslide. In recent several decades, more and more ground surface displacement monitoring devices were brought to the market, such as the automatic total station, theodolite, digital level, borehole inclinometer and GPS based instruments, etc. Based on these modern techniques, some advanced instruments have been developed and applied to the landslide monitoring, for example, the “landslides early warning monitoring system” (Leonardo, et al. 2002), the “In-SAR” technique (Reevea, et al. 2000), the GPS and satellite geodetic survey based technique (Reevea, et al. 2000), and real-time telemetry technology (Xu, et al. 2007). These monitoring approaches have made significant contributions to the landslide disaster monitoring and forecasting. The major limitations for the ground surface displacement monitoring techniques are lie in the inconsistence between the displacement in ground surface and that in the sliding surface for the sliding mass, resulting in low degree of forecasting accuracy."

Jan 1, 2015

By L. Bratek, K. Jaworek, M. Czaplicka

Methods for arsenic compound removal from aqueous solutions include processes such as: coagulation, adsorption, membrane techniques, electrochemical and biotechnology techniques. Advanced oxidation using both UV radiation and strong oxidizing agents such as ozone and hydrogen peroxide may also decompose these compounds. It is known that effluents from metallurgical processes contain inorganic arsenic compounds in addition to the organic compounds such as: dimethylarsinic acid and phenylarsonic acid. This paper presents the conditions that lead to the formation of deposits containing mainly arsenic, such as pH, the wavelength of the radiation and the type of oxidant, for this type of effluent.

Jan 1, 2014

By Zizheng Zhou

The separation of cobalt from other base metals can be achieved using diffusion dialysis in a two-compartment reactor separated by an anion exchange membrane. In this work, a Neosepta AFX membrane was used to study the separation of various metals in an acid-chloride solution. The separation of one metal from another was investigated on the basis of the various chloro-complex stabilities. The metals investigated included cobalt, nickel, copper(II), iron(III), aluminum, zinc and cadmium. The impact of several critical experimental conditions, including the initial metal and chloride concentration in the feed solution and their initial concentration in the receiving solution, on the separation factor and the metal transfer rate is reported in this work. Effective separation of different metal pairs was achieved under the experimental conditions.

By M. Wallin

Millions of tons of sludge from different metallurgical processes are produced worldwide annually, and the environmental impact of landfilling these often hazardous sludges stresses the need to understand their role as valuable resources. The current work explores the potential of producing a saleable low-phosphorous ferromanganese alloy by utilizing sludge from the silicomanganese industry together with an iron source. The aim of the project is to explore the feasibility and practical challenges related to reduction and dissolution of manganese and silicon from the sludge to liquid metal and slag. Parameters such as ratio of input material as well as the effect of adding limestone and coke to the mixture were explored by thermodynamic calculations and adapted experimentally. Results show that a ferromanganese alloy, in fact, can be formed, while silicon and calcium forms a complex slag that captures a significant amount of impurities.

By G. Akdogan, I. J. Geldenhuys, Q. G. Reynolds

Efficient recovery of titanium from titaniferous magnetite ores continues to be a promising, yet unrealised opportunity, despite significant occurrences of titaniferous magnetite deposits worldwide and the existence of established industrial-scale practices. Current smelting processes only recover iron and vanadium, while the titanium is discarded in the waste slag. These slags are stockpiled and present massive environmental challenges, while still containing value as residual iron, vanadium and titanium. The complex mineralisation of these deposits does not allow for a significant opportunity to separate the titanium and magnetite minerals through normal physical upgrading processes. An upgrading process is therefore required to derive economic value. An efficient process technology could create an opportunity to unlock all three valuable commodities. South Africa’s Bushveld Complex, the largest known deposit of its kind in the world, is known for the high vanadium content but is also associated with relatively high concentrations of titaniferous magnetite. The quality of the Bushveld Complex was one of the drivers for the establishment of the Highveld Steel and Vanadium Company in the mid-1960s. The unfortunate demise of Highveld Steel and Vanadium created an opportunity to review current practices and evaluate the best available process for this complex ore in the context of the three elements of interest. Past and current processes, the nature of these deposits and the potential to recover titanium are assessed to highlight the potential of fluxless smelting of titaniferous magnetite to produce a titania-rich slag as feedstock to the pigment, titanium metal industry in conjunction with recovery of iron and vanadium. Ilmenite smelting practices are proposed as a suitable alternative to achieve the goal, namely sustainable processing. Keywords: Titaniferous magnetite, titanomagnetite, smelting, titania slags, comprehensive processing

Jan 1, 2020

By D. Berkley

The competitive pressure, the increasing energy costs and the environmental regulations impose substantial challenges to the definition of power plants serving industrial facilities. Primary mining and metallurgical facilities have even greater challenges because they are often located remotely, where the fuel supply can be a problem. The absence of a power grid imposes challenges on the reliability and quality of the electrical energy supply. In addition, the facilities usually require thermal energy too, not only electricity. This paper outlines these types of issues that have to be considered when defining a cogeneration plant integrated with a remote located industrial facility. It is addressed to the ?users? of cogeneration facilities rather than to ?generators.? The focus is on analyzing various site-specific design considerations to pre-screen the feasible cogeneration alternatives and minimize the number of options to be analyzed from the economics viewpoint. This approach could substantially reduce the engineering effort and schedule during the feasibility phase of the project. Part 1 of this paper (Berkley, 2003) provides a basic understanding of cogeneration plants of various types to establish a common language. Part 2 outlines and analyzes specific issues that could be of help in the definition of cogeneration installations for remotely located industrial facilities, with a focus on mining and primary metallurgical plants.

Mar 1, 2003