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By Jochen Petersen, Diane Taggart

"At an average of 90.3% (for the period of 1 January 2009 to 30 September 2011), Zincor’s zinc recovery was well below the industry standard of 96%. The losses through the residues, in particular the iron residue, were the biggest contributors to the overall zinc loss. It was believed that this loss could be decreased with the implementation of seed recycling. A plant trial was run to test the implementation of a seed recycle. The rate of seed addition through recycle was increased over a 4-week period. The presence of seed decreased the insoluble zinc loss by providing additional surface area for iron to precipitate onto, and reducing coating of unleached neutralising agent. The soluble zinc loss was also decreased at low and moderate seed recycle volumes. The improvement was attributed to agglomeration growth of the recycled particles, which improves the dewatering characteristics of the precipitate. In contrast, the soluble zinc loss increased at high seed recycle rates. This result was attributed to particle crowding and a low wash ratio.INTRODUCTION The Zincor refinery, which closed in December 2011, was situated just outside of Springs in the Gauteng Province of South Africa and employed the conventional Roast-Leach-Electrowin process, which accounts for 75 to 80% of the annual primary zinc production in the world. The refinery fed up to 220 000 t/a of zinc sulphide concentrate. The major portion of the raw material was sourced in Southern Africa from the Rosh Pinah and Black Mountain mines. Between 20 000 and 40 000 t/a of material was imported to make up the deficit and to improve the grade of the feed material. The iron contained in the zinc concentrates, at an average of 6.03% (for the period of 1 January 2009 to 30 September 2011), resulted in the formation of zinc ferrite during roasting, which is insoluble under atmospheric leach conditions. At Zincor, most of the zinc ferrite was dissolved in the residue treatment plant at elevated temperature and high acid strength. The leach liquor from this aggressive leach contained between 15 to 30 g/L of iron, mostly in the ferric form, and was known as the hot iron solution (HIS). The presence of iron in the liquor had an adverse effect on the zinc operation, particularly on the current efficiency in the electrowinning circuit. Therefore the iron needed complete removal."

Jan 1, 2016

By Kelly O'Konnor

El presente texto señala la historia, geología y exploración del yacimiento polimetálico tipo skarn Antamina. Dicho yacimiento se localiza en el lado sureste del valle de Antamina y su nombre en quecha significa: "Mina de cobre". La evidencia de la actividad minera data de 1850 y posteriormente se realiza la disolución del joint venture en el año 1982. Asimismo, se describe la magnetometría, plano esquemático de alteración y zoneamiento metálico y las reservas del mineral.

Apr 26, 1999

By Edmundo Alfaro Delgado

La geometalurgia es una disciplina transversal dentro de las actividades mineras, que tiene el objetivo de sistematizar las complejidades asociadas a la determinación del valor del recurso y consecuentemente su explotación económicamente favorable. Al integrar la geología, operaciones mineras, pocesamiento de minerales y metalurgia, la geometalurgia pretende mejorar el proceso de evaluación de los recursos económicos y hacerla mucho más efectiva en términos técnicos y económicos. Por ello, el presente texto describe la importancia de dicha disciplina -en tanto incorpora los aspectos de planificación integral de la actividad minera, desde la fase de exploración mineral, los planes de minado e identifica los niveles de producción que dependen de la dureza, moliendabilidad, la recuperación y la calidad del concentrado.

Sep 14, 2009

By Jorge Ganoza

El proceso del diseño de circuitos de molienda (SAG) en la planta de flotación de pórfidos de cobre, flotación de minerales polimetálicos o plantas de cianuración y minerales de oro y plata, implica energía que puede variar al procesar minerales blandos o duros. En este sentido, se buscan las operaciones que acepten el tratamiento de minerales duros en los circuitos de molienda y la clasificación del mineral de acuerdo a la dureza.

Sep 1, 2016

In response to increased aluminum demand, U.S. producers have begun reactivating primary aluminum capacity which was shutdown during the 1974-1975 recession. Reynolds Metals Company started up almost 80,000 tons per year of idled capacity at Listerhill, Alabama, and Jones Mills and Arkadelphia, Arkansas plants. Howmet Aluminum Corporation and Alumax announced that the operating rate at their jointly owned facility at Frederick, Maryland was being increased from 75 percent to 100 percent, equivalent to a 44,000 ton-per-year increase in output. Kaiser Aluminum and Chemical Corp. expected to restart one of the two idled potlines at its Mead, Washington facility in May raising its production rate by 27,000 tons per year. ANTHRACITE - The anthracite market for the larger sizes continues at a good level, and although the demand for industrial sizes has been weak, the current trend indicates an increased demand for industrial fines by the steel, auto, and other industries.

Jan 1, 1976

Norton Co., the world's largest producer of abrasives, is enlarging its proppant operation. Proppants are strong chemical particles used to wedge open rock formations in deep oil wells, thereby increasing the well flow rate, sometimes as much as tenfold. Norton" aluminum oxide-based proppant is rapidly displacing less durable materials. The company is building the world's largest proppant plant in Fort Smith, AR. ALUMINUM--See also REFRACTORIES The price of primary aluminum ingot was increased by several producers in July. Kaiser Aluminum & Chemical Corp., and Revere Copper & Brass Inc. increased the price of primary aluminum to 63.0 cents per pound, effective July I. Reynolds Metal s Co., Anaconda Aluminum Co., Howmet Aluminum Corp., and Marti n Marietta Aluminum Inc. increased the price of 99.5% primary aluminum ingot to 63.0 cents per pound, effective July 5, The Aluminum Company of America increased the price of aluminum ingot to 62.5 cents per pound, effective July 9. The range of prices at the end of the month was 58.5 to 63.0 cents per pound.

Jan 1, 1979

1. Domestic Production and Use: In 1977, 12 companies operated 31 primary aluminum reduction plants, with 3 firms accounting for 65% of production capacity. Washington, Oregon, and Montana accounted for 31% of the total capacity; Gulf Coast States 23%, Northern States 26%, and other Southern States 20%. Based on estimated producer prices output of primary metal in 1977 Has valued at $4.6 billion. Aluminum consumption by 25,000 firms was centered 'in the East Central United States. Of aluminum consuming industries in 1977, building accounted for about 25%; packaging 22%; transportation 21%; electrical 11%; consumer durables 9%; and other uses, 12%.

Jan 1, 1978

By Mario Samamé Boggio

El presente texto describe el origen del saber técnico en los países hegemónicos, la función de las universidades y la situación de la enseñanza respecto de la carrera profesional de Ingeniería.

Jan 1, 1979

By Luis A. Maradiegue

El presente estudio refiere el diagnóstico correcto de la silicosis a través de una revisión de la historia ocupacional, historia clínica y el ambiente del trabajo del trabajador. El control del trabajador y del ambiente de trabajo, lo deben realizar los médicos e ingenieros, para evitar o retardar la progresión de la silicosis o enfermedades respiratorias y facilitar el cambio de lugar de ocupación del trabajador, controlando el medio ambiente, respectivamente. Asimismo, en la evaluación del riesgo silicógeno en una industria extractiva, el ingeniero utiliza el instrumento Midget Iapinger, el muestreo, y los métodos de "campo brillante" para la cuenta de particulas, y la dispensación de la muestra en aceite de inmersión para la medición de partículas. El análisis de sílice libre comprende los métodos petrográficos, difracción de rayos X y el de fusión. Finalmente se hace una interpretación de resultados y se presenta un informe detallado de la condición de salubridad del trabajador.

Aug 20, 1963

By Benjamin Smith Lyman

PAGE I. ANCIENT HISTORY,........... 57 Accepted Fables ; Babylonian Mapping ; First Surveying. II. COMPASS,.............59 Chinese Invention; Marco Polo; First European Compasses ; Early Knowledge of Variation ; Plotting with the Compass ; Hanging-Com pass ; Supposed Gravitational Error ; Merit of the Compass. 111. Telescope,............63 Origin (Roger Bacon, Porta, Digges, Lippershey, Galileo) ; Improvements (Micrometer and Cross-Hairs, Rittenhouse's First Telescope, Platinum Cross-Wires, Telescopic Sights, Reflecting Telescope, Achromatic Lens, Kellner Lens in Erecting Telescope, Inverting Telescope). IV. Theodolite,.............81 Origin ; Derivation of the Name. V. TranBit,.............86 First Surveying Transit; Edmund Draper. VI. Instrument-Parts,..........89 Ramsdenl a Dividing Engine ; Fineness of Graduation ; Conical Gradua tions ; Full Vertical Circle ; Leveling-Screws ; Shifting Tripod-Heads ; Hoffman-Harden Tripod-Head ; Heller & Brightly's Improvements. VII. OTHER INSTRUMENTS AND APPLIANCES,......100 Sunflower; Plummet-Lamp; Chains and Tapes. VIII. SCOTT'S TACHYMETER,.........104 IX. Nomenclature and Classification,.......105 Names; Grouping. Surveyors are much indebted to Mr. Scott for so vigorously attacking the subject of the origin and history of mine-surveging instruments, the compass, the telescope, the transit and other apparatus. He is not afraid of the dark, nor yet foolishly bashful in broad daylight. He does not recoil from the obscurities of the earliest times and the most difficult historical points; and, with commendable public spirit, he makes his own invention known to his fellow-workers, and challenges their criticism. He has, moreover, elicited the praiseworthy emula-

Jan 1, 1902

By Walter F. Morton

La mina y la planta concentradora de Chilete de la Northern Peru Mining & Smelting Co., están situadas en Cajamarca, norte del Perú, donde en 1948 se encontraron cubicadas cantidades de minerales de plomo- zinc, que fueron añadidas a las reservas de la mina. Posteriormente se construyó una planta de flotación que permitió mejorar la filtración de los concentrados y a su vez aprovechar al máximo los minerales de la mena como la ganga, así como su concentración de valores económicos en los mismos.

Jun 20, 1954

By Charles Hardy

?POWDER METALLURGY? is the production of semiformed or fully formed metal products by compressing metal powders. It had its beginnings in the fabrication of tungsten and molybdenum bars and wire by compression, sintering, and swaging. Powder metallurgy, although still in its infancy with other metals, has shown remarkable progress in recent years. Production of Metal Powders-The first step in any powder-metallurgy process is the production of metal particles of suitable shape and size. Mechanical processes for producing metal powders, as by crushing, stamping, or grinding, are usually not suitable, as the resulting particles may cause laminations and decreased strength in the finished articles. The principal metal powders now in use on a large scale are produced by electrolysis or by reduction of metal oxides by gases.

Jan 1, 1936

By Charles F. Coleman

Kinetics studies and other rate measurements are reviewed in the amine extraction of uranium and of some other related and associated metal ions. Equilibration' is relatively fast in the uranium sulfate systems most important to uranium-hydrometallurgy. Significantly slow; equilibration-has ' been encountered' in some other systems. Most of the recorded rate information, both qualitative and quantitative; has come from exploratory and, process-development development work, while some kinetics studies have been directed specifically toward elucidation of, extraction mechanisms. In contrast to some other extraction systems, relatively little attention has been given to the kinetics of uranium extraction by amines. This is because investigators have not been troubled by slow extractions. Instead, when rate limitations have been of concern in amine extraction (Amex) process developments, they have been mainly from slow phase disengagement rather than from slow equilibration. Nevertheless, taking uranium together with several other elements that are closely related to it or associated with it in typical processes, a considerable body of rate information has been recorded.

Jan 1, 1979

By WL Wagner

This report presents a quality control approach to the derivation of strategies for monitoring a work environment; specifically, the environment in underground mines where diesel-powered equipment and blasting agents are used. The approach is presented as a series of 22 steps called the Monitoring Strategy Development Scheme. The scheme is an orderly method for selecting from a number of options a strategy or tactics to cost effectively meet the requirements of a chosen objective related to the monitoring of breathing zone air quality. The scheme provides a format to quantify many of the factors that influence the selection of on strategy or tactic over another, and to ensure that important considerations are not neglected. The premise that breathing zone air in work environment can be considered to be manufactured product and that, therefore, conventional quality control approaches are applicable, is introduced. Typical approaches to the quality control of manufactured products and how these approaches can be applied to the selection of monitoring strategies are discussed.

Jan 1, 1983

By K. H. J. Clarke

"ALTHOUGH nickel was not identified as a separate element until a Swedish scientist, Axel Frederick Cronstedt, did so in 17 51, its utilization dates from pre-historic times. From its humble beginnings nickel has grown in importance until, today, in our clocks, television sets, automobiles, and air-planes, in our bridges, tableware, farm implements, and the equipment which processes our food, it is constantly at our service.For convenience in assembly, data and information relative to The Marketing of Nickel will be outlined in five phases: (A) Sources, (B) Distribution, (C) Utilization, (D) Market Development, and (E) Conclusions."

Jan 1, 1960

By Harvey T. Gracely, Mark J. Woodhull

DURING the past few years a marked refinement has taken place in the design of electric power shovels for the mining industry, increasing their digging ability and speed of operation without adding to their total weight. The increase in pay load has been accomplished by a more rigid engineering analysis of shovel design, involving the adoption of new special alloy steels, new sections, and new welding methods. Emphasis has been placed on lightness with increased strength, which is most clearly shown in the front-end equipment where dipper, handle and boom are new in design, material, and construction.

Jan 1, 1938

By . Adolfo Farfán C

El presente trabajo describe los problemas ocasionados por los incendios en la mina de Cerro de Pasco. Si bien es raro que se origine un incendio en minas de características especiales como la de Cerro de Pasco, no se descarta la posibilidad de un corto circuito o algún otro infortunio. Por ello, es necesario conocer las causas, zonas de vulnerabilidad, los métodos de minado, ventilación, los antecedentes del incendio, origen, combate, las cuadrillas de rescate minero y la prevención de este desastre.

Nov 20, 1978

By Doris M. Hyde

The Government of Belize maintained strict control over spending in 1982 as a means of protecting its import-dependent economy against the effects of a general worldwide recession. The modest economic performance was not expected to differ substantially from the $152 million2 gross national product (GNP) estimated for 1981. Exports and reexports were expected to decline in 1982, partly as a result of the Mexican peso devaluation. Imports were also expected to decline slightly in 1982, but the overall trade deficit was projected some-what higher than the $44 million experienced in 1981. On September 21, 1982, Belize became an independent state. As a result, the new Government became eligible for assistance from international organizations such as the International Monetary Fund, the International Bank for Reconstruction and Development (World Bank), and the United Nations Development Program (UNDP). Belize's independence from its former status as a colony of Great Britain was marred somewhat by the unsettled territorial dispute between Great Britain and Guatemala. Guatemala declared Belize was a part of Guatemala and. therefore. refused to recognize it as an independent state. Negotations between Great Britain and Guatemala continued without resolution.

Jan 1, 1984

By Raymond E. Davis

LET'S imagine we are at the Grand L Coulee Dam, where daily 15,000 barrels of low-heat Portland cement and 27,000 tons of processed aggregate in various sizes are mixed to produce 30,000 tons of concrete. Inspect the autographic records which show for each 4-cu-yd. mixer batch of concrete the weights of its constituent materials including its several sizes of aggregate, cement, and water, and which also show the period of mixing and the consistency of the mix. Watch the inspectors sample and test the aggregate for gradation and moisture content of sand, and sample the concrete for homogeneity. Watch the huge buckets deposit the concrete in the forms. It looks too dry to handle, but the concrete vibrators make it melt away. Just enough vibration fully to com- pact the mass, but not enough to produce segregation of the materials; the inspector says when. See the sprinkler system covering all hardening concrete with a spray so that it may not thirst for water. Watch the cleaning of the top of an old lift preparatory to placing a new lift; the sand blasting; the blow-down; the mop-up; the minute inspection.

Jan 1, 1939

By A. Eccles

Phase designs are the foundation upon which all open pit mine sequence optimizations and budgets should be built. Unfortunately, at times, mine engineers skip the step of developing realistic pit phase designs - designs that include access ramps and mineable widths. Without mineable phase designs, their optimized schedules are based on theoretical pit shells or ?quick-and-dirty? plans with no ramps. The output from such optimizations is almost always overly optimistic. Without mineable designs, the production estimates are misleading, because they overestimate ore, and underestimate waste stripping requirements. Worse yet, when plans are not based on realistic phase designs, they can point to exactly the wrong decision in feasibility studies (i.e. ?go? when it should be ?no-go?). This paper discusses the importance and features of good pit phase design, and demonstrates the pitfalls of relying on optimized production sequences that are not based on properly designed pit phases.

Feb 27, 2013