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By D M. Aranha, M A. Fonseca, M Echtern

The regional syndeformational metamorphism affecting the Itabira Iron Formation (IIF) at Quadrilßtero Ferrffero (QF) was formerly discussed by Dorr (1965), who proposed that quartz grain size could monitor the metamorphism, according to James (1955), and that the formation of haematite could be the result of the synchronous metasomatic process. Herz (1979) suggested the existence of three metamorphic zones, not mentioning the haematite formation. It could be observed that the primary oxide phase in the IIF is magnetite and most of the hard haematite was derived from the metamorphic replacement of magnetite, forming micaceous or schistose haematite. Differently from most iron formations in the world, the formation of haematite deposits at QF occurred under high oxygen fugacity during metamorphism. The haematite microlaths display a strong preferred orientation, which determines the alongated shapes of the fragments. The terms foliated and unfoliated haematite have been applied by Dorr to the micaceous or schistose haematite, and to the isotropic, hydrothermally derived haematite. Under the microcope, the haematite exhibits a strong crystallographic or lattice orientation encircling the magnetite and martite porphyroclasts. The strain rate determined and defined the textural variation, size and economic importance of the deposits and the ore grade. Metamorphism at QF increases eastward and resulted in the formation of a gruneritic Fe-Mg amphibole, at the western portion, followed by a cummingtonitic amphibole at the central-western part, succeeded by the actinolite zone at the central-eastern part, and finally to the tremolite-anthophyllite zone to the east. These zones, arranged in a north-south pattern, can be followed in the pelitic units, whereas appear sericite-chlorite, kyanite-chloritoid and garnet-staurolite respectively. Carbonate geothermometry in IIF also may support the metamorphic variations. At the western zone the haematite forms small lenses within the itabirite, P-contents are slightly higher than in the remaining IIF, haematite grain size is minute, resulting in a submicaceous texture and the amount and dimension of relict magnetite within haematite is greater than in the other parts of QF. Jangada and Serra Azul deposits are examples of this zone. The central-western zone is characterised by significant haematite deposits, in considerable quantity and size, haematite grain size increased, in order to produce a micaceous texture, the P-contents and the amount of magnetite decreased. Pico do Itabirito, Cappo Xavier, Capitpo do Mato and Tamanduß correspond to the deposit type of this zone. At the eastern-central portion the amount of the hard haematite deposits decreases, increasing the soft haematite ore due to higher strain rates. However, it can be perceived that the relict magnetite almost disappeared and the haematite grain size became coarser than the haematite from the western zones. At the eastern zone, the haematite deposits exhibit typical schistose texture, the magnetite porphyroclasts are absent and the lowest P-grades in the haematitic iron formation. The haematite bodies characteristic from this zone are Andrade, Morro Agudo and the deposits at the Itabira District. The hydrothermally derived compact and isotropic haematite deposits, formed subsequently to the micaceous haematite bodies, were generated after deformation ceased, but under very high fluid pressure. The metamorphic reactions magnetite + quartz + H2O = grunerite + haematite and magnetite + quartz + H2O = grunerite + O2 were decisive in the formation of the metamorphic haematite deposits.

Jan 1, 2007

By George Hope, Brigitte Lacouture

"The Red Dog Mine has increased mill throughput for most years since startup. Although flotation equipment has been added over the last 10 years, the Red Dog metallurgical performance has been restricted by a lack of adequate flotation capacity. Two reduced tonnage trials conducted in 1997 as well as numerous SAG relines have consistently indicated the potential to significantly increase both zinc concentrate recovery and grade with additional flotation capacity. Late in 1999, a new circuit was designed with increased flotation capacity while simplifylng the current circuit, providing for three stages of dilution cleaning, and creating a retreat section. The purpose of the retreat section is to target the more complex particles and allow the chemical environment to be fine tuned for improved iron depression. In total, twentyone (21) Outokumpu OK50 mechanical flotation cells and four (4) 3.66m dia. column cells will be added to the current flotation circuit. The VIP (Value Improvement Program) Mill Optimization project is also addressing thickening, water treatment and power issues and has a total budget of $US105 M. Startup of equipment will be phased in to minimize the impact on current operations and is expected to be complete by the end of Q3-2001.INTRODUCTIONRed Dog Operations started production in November 1989. The mine is located above the arctic circle in northwest Alaska. It is linked by an 80 km road to a port-site facility where the concentrate is stored. Concentrate is shipped to markets throughout the world during the one hundred (100) days of open seas. Typical of sedimentary exhalative deposits, the metallurgy proved to be challenging and coupled with many mechanical shortcomings, the initial few years were very difficult. The start-up issues were slowly resolved and in 1998, a major grinding expansion, the PRI (Production Rate Increase) project, was completed. The project was designed to allow a 40% increase over the 1995 throughput. In 2000 mill throughput was 3,050,000 tonnes to produce a total of 960,000 and 140,000 dry tonnes of zinc and lead concentrates respectively, making Red Dog the largest zinc concentrate producer in the world. To address a shortage of flotation capacity remaining from the PRI grinding expansion, a project designated as the VIP (Value Improvement Program) Mill Optimization project was initiated. The mill optimization project is targeted to produce 1,100,000 tonnes of zinc concentrate at 56% zinc grade and 87% zinc recovery. The project will add twenty-one (21) Outokumpu OK50 (50m3) flotation cells, four (4) 3.66mO column cells and address water treatment, thickening and power generation capacities."

Jan 1, 2002

By Walter Nuñez

La finalización de la estimación de reservas de un modelo de mina cuestiona la asertividad del modelo de Mina para la planeación minera. En ese sentido, el presente texto señala la Reconciliación como la comparación real histórica de tonelaje, leyes y contenido fino estimado, entre el modelo de mina y planta concentradora. La reconciliación permite conocer y ajustar mediante el uso de factores, la planeación mensual y anual de los siguientes años de la operación minera, y así cumplir con los compromisos mensuales asumidos de envío de contenido fino desde mina. Así también se muestra el proceso que sigue la explotación minera a tajo abierto en Toquepala, las variables que influyen en la variación de la reconciliación y algunas pautas a considerar para minimizar estos errores de reconciliación entre mina y concentradora.

Sep 19, 2006

By Rebecca Hope, Derick Moolman, Frikkie Malan

"Despite the lip service that has been paid to pro-active plant maintenance processes over recent years, a significant portion of maintenance in industry is still reactive. The business driving force to prevent expensive production opportunity costs arising from “break-down maintenance” is obvious. Various benefits can be derived from successfully deploying remote equipment diagnosis technology and associated business processes.From an end-client’s viewpoint these include the ability to predict and take actions to prevent equipment breakdowns, increasing the lifetime of equipment by responding to appropriate operating instructions and therefore improving the return on capital expenditure. Better planning and scheduling of maintenance priorities and resources with performance measures like an Equipment Health Index are also possible. The knowledge that a qualified supplier engineer is constantly in touch with the operating conditions of their equipment, albeit remotely, is more than a comfort, and can be translated into quantifiable cost savings and improved supplier service levels."

Jan 1, 2003

1. Domestic Production and Use: In 1975.12 companies operated 31 primary aluminum reduction plants, with 3 firms accounting for 67% of production capacity. Washington, Oregon, and Montana accounted for 37% of the total production; Gulf Coast States 21%, Northern States 29%, and other Southern States 13%. Output of primary metal in 1975 was valued at $3.0 billion. Aluminum consumption by 25,000 firms was centered in the East Central United States. Of aluminum consuming industries in 1975, building accounted for about 21%; transportation 19%; electrical 14%; packaging 18%; and consumer durables, 9%.

Jan 1, 1976

By C. P. Patel

"The Sturgeon Lake Joint Venture volcanic massive sulpide deposit was discovered in 1970. Milling was started by Falconbridge Copper Ltd. at Sturgeon Lake in September 1974. The Sturgeon Lake pit and mill are located 88 kilometers by road northeast of Ignace, Ontario. IgnE1ce is a town of some 2800 people located on the Trans-Canada Highway, 241 kilometers west-northwest of Thunder Bay. The mill is treating an average of 1100 TPD producing separate concentrates of copper, lead and zinc. Initially, difficulties were experienced in achieving accept-able concentrate grades and recoveries but these were eventually overcome. This presentation describes current metallurgical strategy as practiced at the Sturgeon Lake mill.But first, a few words about the type of ore being treated. In geological terms the ore is classified into two main categories. They are the massive sulphides with underlying zones of stringer sulphides as illustrated in Fig. 1. The plan view is shown in Fig. 2. The areas of East-limb and North-limb are as shown. These last two ores have suffered enough alteration to cause problems during treatment. The massive sulphides consist of chalcopyrite, sphalerite, galena, tetrahedrite and small amounts of pyrrhotite among other gangue materials. The stringer ore is comprised of predominantly chalcopyrite intrusions into rhyolite and has lesser amounts of sphalerite and tetrahedrite. At present we are treating a predetermined blend of massive and stringer ores from zones that have been metallurgically tested to ensure compatibility with current treatment procedure in the plant. Ore responding to this treatment is classified as normal ore while the ore proving incompatible is classified as north-limb ore or east-limb ore."

Jan 1, 1980

By S. Heukelman

Zinc or, a zinc refinery in South Africa, uses oxygen enrichment of up to 26% O2 in its fluidizing air to increase concentrate-throughput in its fluidized bed roasters. The aim of the study is to determine whether O2 enrichment can be reduced by introducing micro-pelletized concentrate into the feed blend, while maintaining concentrate throughput rates and calcine quality. A laboratory scale fluidized roaster was used to determine the strength and oxidation kinetics of suitable micro-pellets. The strength of the pellets was determined by the extent of attrition during roasting. It was found that micro-pelletization decreases the fines in the feed to the roasters; the ?500 µm fraction decreased from 87% to 10%. The micro-pelletized particles do break down during roasting, which increases the -500 µm fraction to 31%. The general morphologies of the roasted particles are similar to those found by previous workers. Micro-pelletized concentrate particles require more time than non-pelletized concentrate particles to oxidize in the roasting step, although this is less than the mean residence time of the Zincor roasters. Roasting micro-pellets in O2-enriched fluidizing air increased the reaction rate.

Jan 1, 2011

By A. Brown

This report details work performed and results obtained in a study of the water management aspects of oil shale mining and retorting in the Piceance Creek Basin. Three specific sites were investigated, and optimal water management systems for both conventional and in-situ extraction processes were generated. Water-related legal and environmental constraints on development were identified and the water management schemes were developed in compliance with these regulations. Limitations on shale oil production implied by limited water supplies were evaluated. Potential Basin-wide effects of development were evaluated using a computer model, and mitigation strategies were developed. Recommendations for additional investigation and analyses were presented.

Jan 1, 1977

By Walter Díaz Cartagena

El suelo es uno de los recursos más importantes del agua -en tanto sustenta la vida natural y fuente de alimento para toda la especie terrestre. Por tal motivo, el presente texto señala los planes y estrategias para el cumplimiento de los estándares de calidad (EKA) de los suelos. En la promulgación de D.S. N°02 2013-MINAM que aprueba dichos estándares, se establece el último componente por norma para conocer la cantidad de contaminación del suelo. Este decreto propone una serie de etapas en la gestión de suelos contaminados que van desde la ecuación de los instrumentos de gestión ambiental, la investigación de situación de estos suelos contaminados en la zona de producción para determinar el estado en el que se encuentran y la recuperación ambiental por parte de un plan de descontaminación de suelos.

Jul 1, 2014

By Mark S. Sanders

There is a growing awareness among mining professionals that the human factor plays a significant role in safety and productivity. Since the 1960's, the science of human factors, or ergonomics, has been making inroads into the mining industry, and a considerable amount of research has documented human-factor-related mining problems and solutions. This Bureau of Mines report is directed toward summarizing the application of human factors to improving safety, productivity, and the general physical and psychological working conditions of miners. The aim of this report is to familiarize the readers with the role of human factors in the mining industry and the benefits that can accrue by systematically applying available human factors principles and data. The text contains 10 chapters dealing with human, equipment, and environmental factors. Each chapter builds on the previous chapter; therefore, it is recommended that the chapters be read sequentially However, if the report is used as a supplemental text, say in a mining safety course, chapters can be assigned in any order to supplement other readings.

Jan 1, 1988

By Yun-Jie Wei

Seismic areas were in the eastern margin of the Qinghai-Tibet plain, whose structures were complicated, mainly composed of Maowen fault, Yingxiu fault and Pengxian-guanxian fault. The rapid rise of the Qinghai-Tibet plain led the crustal material of the eastern edge to move to the southeast along the faults on a large scale since the late Cenozoic; Minshan block structure and Long Men Mountain tectonic zone represented the strong nappe thrust movement as the east boundary of Chuanqing slip block; the stress was accumulating when squeezed, which to a certain extent resulted in breakdown of the crust, and earthquakes. The shock speed, high-energy accumulation, and the reversed dextrorotation of the earthquake fault characteristics et al. happened, which caused the development of secondary geological disastersts. According to on-site investigation, the typical geological disasters had thrust rock collapse, the instability deposit, the revival of potential debris flow et al. whose genetic model had been analysed.

May 1, 2009

By Louis J. Sousa

In November 1989, the U.S. Bureau of Mines sponsored a 2-day conference to stimulate thinking and discussion about changing materials technologies and implications for the Government's materials information programs. On the first day of the conference, speakers provided overviews of developments occurring in each of the major materials groups. Emerging technological developments, applications, economic and national defense significance, intermaterial competition, and potential market growth in advanced plastics, polymer composites, ceramics, metals, and electronic materials were described. In general, the speakers forecast advanced materials market growth rates in excess of overall gross national product (GNP) though high costs will tend to limit growth outside of aerospace, defense, electronics, medical equipment, and other typically high value-added businesses. On the second day, a wide range of speakers representing several facets of the materials community described how advances in materials technology are creating a need for new types of data, statistics, information, and analysis. Reflecting the speakers' broad range of organizational, professional, and personal perspectives, an array of information needs was identified. Most requirements, however, seemed to fall into one of five major categories: Federal materials research activities, material standards, market and economic information, health and safety, and public policy.

Jan 1, 1990

Casing or lining pipe is used in boreholes for the following reasons:1. To preserve the hole while drilling and after it is finished.2. To shut water out of the hole or to isolate any particular water, gas, or oil-bearing stratum.Deep holes can seldom be drilled without casing, and only when in firm strata. If caving from the walls is at all likely while drilling, casing is necessary in order to prevent the tools horn being buried...

Jan 1, 1924

By Paul Sarnoff

The economics of precious metals -- depending upon who is involved --could be the economics of hope, of fear, indeed of profit and perhaps survival. For those investors seeking capital gains in a puzzling economy, precious metals involve the economics of hope. Those who are convinced that currency soon won't be worth the paper it's printed on turn to precious metals because of the economics of fear. Gold and silver have been a storehouse of wealth since biblical times. The economics of fear during the past 500 years on the Continent has caused almost every European family to make sure a private stockpile or hoard of gold, silver or coins is at hand in case the paper currency of their country undergoes the kind of disaster that came to the German Mark after World War I. Understandably, for mining companies involved in the production of precious metals, the elements of operations and management are directly concerned with the economics of profit -- and perhaps survival. To the American miner the price of precious metals in the marketplace is a matter of daily concern. After decades of selling silver to the US Government at 64.64 cents an ounce, producing silver mines suddenly became faced with prices breaking $5, $10 and $20 per ounce, and approaching $50 an ounce during the period 1978-1981. What should the miner expect one year in the future? Five years?

Jan 1, 1981

By Glenn Buchana

El presente texto señala algunos aspectos técnicos y comerciales del dragado del depósito fluvial. Para ello, es necesario conocer el origen y desarrollo del depósito fluvial. El depósito fluvial es una masa de grava superficial, la cual es producto del desmoronamiento y erosión de rocas sólidas que contienen partículas o pepitas de oro, diamante, estaño, platino u otros minerales valiosos que proceden de las rocas o de las vetas. Entre los tipos de depósitos aluviales tenemos: depósitos aislados pequeños y poco profundos, los depósitos de mediana profundidad, depósitos profundos y los marinos. La explotación se realiza a través de tres sistemas: draga cortadora de succión, la dragalínea de cangilones y la planta de tratamiento flotante.

Nov 1, 1979

Over 500 industrial, academic, and government representatives from Europe, Canada, and the United States attended the first large symposium ever held in this country on fly ash utilization and technology, March 14-16, 1967, at Pittsburgh, Pa. Sponsored by the Edison Electric Institute, the National Coal Association, and the Bureau of Mines, the symposium featured 27 formal presentations by leading reports from the United States and Europe on all major phases of fly ash production, utilization, and research. Representing the three sponsoring organizations were Edison Electric Institute, James D. William- son, The Dayton Power and Light Co.; National Coal Association, James R. Garvey, Bituminous Coal Research, Inc; and Bureau of Mines, Harry Perry. Symposium chairman was John H. Faber of the Bureau of Mines. Gerard C. Gambs, Consolidation Coal Co., addressed the opening session. Moderated by Mr. Garvey, President and Director of Research of Bituminous Coal Research, Inc., the opening session was devoted to a discussion of the nature of the fly ash problem, including availability, specifications, and limitations on its use. Subsequent sessions covered Fly ash marketing, fly ash utilization in concrete and masonry products, specialized uses, and recent developments in basic fly ash research. Others serving as session chairmen were Oscar E. Manz, Associate Professor of Civil Engineering, University of North Dakota; Mrs. Katharine Mather, Chief, Petrography and X-ray Section, Concrete Division, U.S. Army Engineers Waterways Experiment Station; Mr. Williamson, and Mr. Perry.

Jan 1, 1967

By K. E. Barnes

"The “Jameson Cell” flotation cell was developed at Mount Isa Mines in the late 1980’s to address deficiencies in our flotation column installations. Early base metal installations had a variable record. The test work and trials showed they made an improvement metallurgically when operated correctly, but performance of the early installations was hindered by a range of operational and maintenance issues. The installations needed to be more robust, and we needed a better understanding of how to successfully integrate the cells into the plant flow sheet.During the 1990’s, Jameson Cells had great success in coal fines flotation and organic removal in SXEW applications, and became the standard in these applications in Australia. These installations improved the cell design and materials of construction and the cell flow sheet design, to make it low wear with self-regulating control, producing good performance with little operator input.These improvements have enabled a fresh look at the use of Jameson Cells in base metals. Recent new installations have shown significant benefits in “hybrid” circuits, that combine the best features of both Jameson Cells and conventional flotation cells, achieving better overall circuit performance in a smaller footprint than either technology could do by itself.Case studies of successful base metal applications are discussed, using size-by-size mineralogical performance to explain the improved circuit performance. The new methods of flow sheet test work design are also described."

Jan 1, 2006

By Luis Porras T.

La explotación de minas de cielo abierto requiere de la estabilidad de los taludes puesto que estos aseguran el eficiente minado de los bancos inferiores y garantizan las condiciones para los servicios auxiliares. Por ello, el presente trabajo señala el método de voladura controlada como el más adecuado para la estabilidad del talúd en explotaciones de límites finales. Dentro de este método, el criterio de velocidad pico de partícula refiere el grado de vibración producido en el terreno por los disparos, ajustándose en el cálculo de carga de los taladros. Sin embargo, en el caso de la mina Toquepala y por razones de índole estructural, el método de minado se aplica de forma moderada la zona Este. Asimismo las condiciones de este método quedan supeditadas a las condiciones geológicas, la infraestructura que se desea proteger y a los servicios auxiliares a complementarse.

Aug 26, 1988

By S. R. Dismukes

Mining is likely to be targeted by The United States Environmental Protection Agency (“EPA”) as one of its key enforcement targets for fiscal year 2002-2003. Identifying the mining industry as an enforcement target, coupled with an increase in enforcement activity in recent years, places each mining operation at increased risk of receiving enforcement attention. A properly developed and implemented Environmental Management System (“EMS”) tailored for your operation is invaluable in reducing the risk of incurring liability for non-compliance. At the heart of an effective EMS is an audit program that checks the company’s compliance with environmental requirements. In addition, audit privilege (in select states), voluntary self-disclosure, and the attorney-client privilege serve as very effective tools for managing those liabilities that may arise during auditing a well-developed program. Of course, these latter tools are effective only if the auditing program is properly structured and properly managed. EPA and some states also provide varying degrees of immunity for environmental violations that are voluntarily disclosed in writing by the company. However, self-disclosure laws and policies typically prescribe stringent requirements for parties seeking to take advantage of them. For example: U.S. EPA has recently extended the time period in which to provide full written self-disclosure to 21 days. However, U.S. EPA’s revised Self-Disclosure guidance also addresses when a company obtains knowledge of a violation for purposes of triggering the 21-day clock and specifically extends the knowledge requirement to include the company’s agents and consultants. This expansion increases the difficulty companies may have in clearly defining and managing when they obtained knowledge. This difficulty increases the importance of managing factual development and the strategic use of other

Jan 1, 2001

By Matthew Preedy, Brett Campbell, Jim Rush, Alan Howard, Derek Penrice

All Rights Reserved. Printed in the United States of America. Information contained in this work has been obtained by SME, Inc. from sources believed to be reliable. However, neither SME nor its authors guarantee the accuracy or completeness of any information published herein, and neither SME nor its authors shall be responsible for any errors, omissions, or damages arising out of use of this information. This work is published with the understanding that SME and its authors are supplying information but are not attempting to render engineering or other professional services. If such services are required, the assistance of an appropriate professional should be sought. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher. Any statement or views presented here are those of the authors and are not necessarily those of SME. The mention of trade names for commercial products does not imply the approval or endorsement of SME.

Dec 1, 2018