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By Shular R. Scudamore

There was a time when heavy-duty apron feeders were built to last almost forever. The machines were heavy and built to maintain certain expected longevity and reliability. Increasing emphasis on return on capital leads to cost-effective designs. Costs can be increased or decreased, depending on customer specifications and the design philosophy of the feeder manufacturer. Specifiers can make important contributions to cost effectiveness. To do so, this article describes what should be known about planning with a supplier for heavy-duty apron feeders. There are several factors that should be considered, including capacity, characteristics of material carried, length, method of feeder loading, degree of lift, hopper opening, pan construction, and type of drive. Today's apron feeders are built in various sizes and with a variety of components to handle heavy, lumpy, or abrasive materials that can ruin lighter feeders. Careful feeder selection is important if it is to provide a controlled feed rate, absorb huge impacts, be used with long hopper openings, and have a relatively low power-perton capacity. Variations in systems and materials demand that each feeder be designed for its application, drawing on a wide range of components. Therefore, certain factors must be considered before final specifications are drawn. Capacity The design and application of an apron feeder is based on how material passes through a given system over the feeder into processing machinery. The processing machinery's capacity governs other equipment and productivity of the flow. From this basic information, related sizes of upstream equipment can be determined. Of these, the apron feeder acts as the "mouth and neck of the bottle." No more will pass than the mouth and neck will accommodate. Everything in the apron feeder design, from dimensions to power, is based on processing machinery. Material Considerations Are Vital Just as the nature of materials to be crushed or screened affects capacity and productivity of a crusher or a grinding mill, so does it affect capacity and performance of a feeder. Lump size must be identified closely so the pan width can be selected to accommodate the maximum lump with room to spare. For example, a lump size of 760 mm (30 in.) indicates a pan width of 1.5 m (60 in.) While two times the maximum lump is considered minimum width, if the maximum lump

Jan 12, 1983

By Jacinto Sack Arzola

El presente trabajo señala el proceso de obtención de zinc en la refinería de Zinc Minero Perú, cuya primer barra la obtuvo en 1981 e inició su producción en 1982. Asimismo se describe el diagrama de flujo de la planta electrolítica de zinc, donde el tratamiento de los residuos lixiviados de zinc se desarrolla a través del método jarosita, cuya purificación de la solución de sulfato de zinc es contínua y se desarrolla en dos etapas: la electrodisposición que se realiza en cátodos tipo jumbo,, y el manipuleo y deslaminado de los cátodos que son semiatomáticos.

Nov 8, 1982

By L Hussey, H Thanasekaran, J Kohmuench

Conventional flotation technology has historically failed to achieve high recoveries when treating <15 µm particles (Lynch et al, 1981). The new StackCell™ flotation technology was developed to specifically target this particle size range, and was tested at pilot plant scale at Mt Keith Nickel Concentrator. The streams tested, Slimes Rougher Tailings and Fines/Slimes Cleaner Tailings, represent 21% and 11% of the total nickel lost to tailings in the plant. Laboratory scale test work indicated that an economically significant fraction of these losses was consistently available to be recovered by additional flotation. The pilot plant experimental scope included over 50 tests. A grade recovery curve for each stream was developed, as well as information on the effect of ore type, feed rate, wash water, air flow, collector and frother on the performance of the cell. The single StackCell was able to achieve nickel recoveries of 16.8% and 16.5% on the Rougher Tailings and Cleaner Tailings, respectively, at grades consistent with these blocks. Additional test work of the StackCell in a cleaner scalper duty yielded final quality concentrate with a maximum nickel recovery of 59.5% for the single stage StackCell. Laboratory scale simulation of the downstream impacts of the StackCell operating as a cleaner scalper indicated a net recovery benefit of up to 2.0% for this cleaner block.Tests were completed to compare residence time requirements of the StackCell, as compared to conventional flotation. In 55 seconds, the pilot plant StackCell achieved 50% of the recovery of a 960 second laboratory scale conventional flotation on the same feed material. The apparent improvement in flotation kinetics is attributed to the novel high intensity aeration system, which provides efficient bubble-particle contact thereby shortening the residence time required to achieve high recoveries. The smaller footprint and lower energy costs of such a cell are also benefits of this technology, which is being considered for industrial scale installation as a result of this test work. Given the industry’s historical poor performance treating slimes with conventional flotation, it is clearly best practice to challenge the status quo through innovative new technology, such as the StackCell.CITATION:Hussey, L, Thanasekaran, H and Kohmuench, J, 2017. The application of high intensity flotation technology at Mt Keith nickel concentrator, in Proceedings MetPlant 2017, pp 259–278 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

By Jr. Blanchette, Claude Bazin, Paul Blatter

"Reporting of the gold production during a month implies to estimate the mass of gold that is processed by a mill, recovered as dorés, lost to the tailings and the change of gold inventory within the plant equipments. Carbon in pulp and/or carbon in leach tanks may contain gold inventory as large as 72 000 g (2 200 troy oz) of gold which needs to be estimated from measurements obtained from sampling the material contained in a tank. Sampling and analysis introduce measurement errors that could be systematic and/or random. This paper examines the effect of measurement errors on the estimation of the gold inventory and on the variation of the inventory in the carbon in leach tanks of the Agnico-Eagle Mines Limited Lapa concentrator. Results of the analysis demonstrate that the inventory is measured with ±10% reproducibility, while the variation of inventory used for mass balance is known with ±300% reproducibility.INTRODUCTIONThe preparation of a production report implies to reconcile measured data with the constraint of material balance over the considered period of production. The sampling and data reconciliation problems were recently reviewed by Morrison (2008) and Jansen (2009a; 2009b). Typically a production report is prepared to cover a period over which the mass conservation hypothesis can be considered valid. In gold processing plants, the change of inventory can seldom be neglected and plays a significant role in material balance calculations. This is particularly true for circuits using carbon adsorption, where the complete cycle of carbon is measured in days.In a 2000 t/d gold ore processing plant, the inventory can be as large as 140 000 g of gold in gravity concentrator bins, carbon in pulp tanks and in the electrolysis circuit. This is equivalent to the mass of gold that fed the circuit during 10 days of operation with 7 g/t feed assays. The change of inventory may therefore strongly impact the production figures and especially the plant recovery at the end of a week or a month. Despite the financial impact associated with gold inventory, few publications are devoted to the subject. Bruington (1991) and Morrison (2008) discussed the problem and stressed the need for the development of reliable methods to estimate the gold inventory in carbon in pulp or carbon in leach circuits."

Jan 1, 2011

By George A. Morgan

The 53 countries that constituted Africa in 1991 accounted for a significant portion of total world output of a number of mineral commodities. However, total output for the continent declined for many major mineral commodities produced compared with that of 1990. Also, Africa's share of total world output of these commodities generally declined. (See tables 1 and 2.) The most conspicuous declines were for cobalt and copper owing to mining and metal processing difficulties experienced by the world's two largest cobalt producers, Zaire and Zambia. Phosphate rock output declined primarily owing to a sharp fall in production from Morocco, also a leading world producer. Morocco's state corporation for phosphate production experienced marketing problems, leading to the decline.

Jan 1, 1993

By Víctor Quinzano

San Juan es una de las principales provincias exportadoras de minerales en Argentina, cuya actividad minera le proporciona mayores recursos. Sin embargo, sus plantas de fabricación (molienda, trituración) producen polvos en el exterior que contaminan el medio ambiente. Por ello, los productores incorporaron nuevas tecnologías limpias que no afecten ni el desarrollo de la producción, ni el medio ambiente. En este sentido, el presente trabajo señala las aplicaciones que el Instituto de Investigaciones Mineras de la Facultad de Ingeniería de la UNSJ ha diseñado a nivel laboratorio, a través de un recuperador electrostático de polvo, el cual responde a las necesidades de los productores y cumple con el objetivo de vinculación y transferencia con el medio productivo. Asimismo, se describe el diseño de un método de recuperación de polvos y el filtro recuperador del mismo, reduciendo el nivel de polvo a un 90% y logrando un precio de venta en el mercado.

Sep 13, 2001

By Raúl Gomero Cuadra

El presente texto revisa el Plan de acción sobre la Salud de los trabajadores realizado entre el período de 2015- 2025 de la Organización Mundial de la Salud. El plan elaborado contiene los ejes de acción estratégicos, objetivos específicos e indicadores dirigidos a la protección de los trabajadores, la promoción de la salud y el bienestar de los mismos, con énfasis en las poblaciones laborales en condiciones de empleo inequitativas y los que están expuestos a condiciones de trabajo peligrosas. Así también se difunde las acciones que buscan disminuir los riesgos del trabajo y las enfermedades no transmisibles en los sectores económicos críticos, el acceso a la salud y la cobertura universal de salud y los determinantes sociales de la salud de los trabajadores.

Apr 1, 2017

By Felipe E. Olivares S

"El presente texto revisa el origen y distribución de los metales raros como parte de un proyecto de recuperación de subproductos de valor comercial en la fundición de La Oroya. Para ello se reeexaminan ocho minerales raros (bismuto, selenio, teluro, cadmio, talio, indio, bismuto, indio de alta pureza), cuya composición de elementos raros se registra en la concentración de algunos productos o residuos. Estos minerales son del grupo del cobre Chalcópirita, Enargita, Tetrahedrita, Bornita y Chalcosita; del plomo: la Galena, Jamesonita y Gratonita, y la Esfalerita que proporciona el zinc. Los concentrados y minerales que entran al proceso de fundición se reparten en tres circuitos principales: cobre, plomo y zinc. Los circuitos de los primeros están ligados entre sí por el sistema de Cottrelles y los procedimientos de las mismas fundiciones, mientras que el último actúa de forma independiente. Por último, es competencia del Departamento de Investigaciones, la recuperación de dichos subproductos a través del proceso de concentración y fundición, como de a búsqueda nuevos métodos en el campo minero y metalúrgico. "

Jul 20, 1956

By Carlos A. Prato, Federico Pinto

"ABSTRACTThe design of drilled shafts often incorporates large factors of safety, for which settlements under service loads are highly influenced by the initial elastic stiffness. In the case of groups of drilled shafts with typical spacing, the elastic shaft-soil-shaft interaction dominates the behavior even for loads close to the bearing capacity, for which the initial stiffness is a key parameter in the design. This paper describes typical trends in results obtained by means of different approaches currently available in the literature for the evaluation of the initial stiffness of a single shaft. An experimental technique that provides a rapid and inexpensive means for the evaluation of the initial stiffness is described, and the results obtained for typical cases are compared with analytical predictions.IntroductionThe behavior of drilled shafts under axial loads is generally governed by the initial stiffness, as the factors of safety considered in design are often large, due to a superposition of conservative assumptions on soil properties and expected loads. In the case of shaft groups, the initial elastic stiffness plays a major role together with the elastic group effects, as nonlinearities tend to localize around the shafts and have a lesser effect than elastic deformations on adjacent elements (e.g., Leung et al., 2010). An accurate characterization of the initial stiffness is thus warranted for the analysis of drilled shafts and shaft groups under service loads.Initial stiffness of shafts may be estimated on the basis of soil stiffness and structural properties of the element by means of numerical methods (e.g., Pinto and Prato, 2006), as well as analytical methods (e.g., Randolph and Wroth, 1978). The soil stiffness may be determined by means of geophysical tests (e.g., Spectral Analysis of Surface Waves, SASW, Stokoe et al., 1994), or correlations with Standar Penetration Test (SPT) blowcounts or Cone Penetration Test (CPT) resistances (e.g., Sabatini et al., 2002).The initial stiffness may also be measured on drilled shafts by means of load tests. Static load tests (SLT), however, have some limitations on measuring small deflections, for which the initial stiffness is often extrapolated by means of large strain measurements (e.g., Chin, 1970), where the SLT measurements are more accurate."

Jan 1, 2014

Low Zinc Prices Close Alcoa Mine Alcoa Mining Co., announced that it will suspend operations at its Hutson mine, near Salem, Ky., because of low zinc prices, January 15. The Aluminum Co. of America subsidiary announced that the low market has made zinc mining un- profitable. About 70 men were employed at the mine, with a production of about 5000 tons of zinc annually. Alcoa said the shutdown would not affect other company operations, with most of the men at Hutson absorbed in the mining firm's fluorspar operations in the same area.

Jan 2, 1953

By Kevan Ford, Getulio Junior, Rob Henderson, Wayne Philips, Chris Martin, Rob Thorpe

"Plant 2 at the Kinross Paracatu gold operation in Minas Gerais State, Brazil, was commissioned in late 2008. Designed to be the largest tonnage, lowest grade gold milling operation in the world, Plant 2’s throughput has steadily increased towards its design capacity of 5087 tons per hour.The plant employs a gold-specific flotation scheme to recover the majority of gold, which is present as discrete free gold particles. Additional gold is recovered by jigs in the grinding circuit, and the jig concentrates are reground, upgraded and subjected to intensive cyanide leaching. The flotation cleaner concentrate is reground and leached using a conventional CIL circuit.One year after start-up, with the plant stabilizing operationally, plant circuit surveys were completed by a joint team from Kinross Paracatu and Blue Coast Metallurgy Ltd. The surveys audited the flotation and concentrate treatment circuits to investigate the metallurgical performance.This paper describes the Plant 2 operation and how the surveys were designed and executed. Some of the quality control systems that were employed to provide meaningful data from such a low grade gold ore are described and findings and actions taken to improve metallurgy as a consequence of the surveys are discussed.INTRODUCTIONThe Paracatu mine is located two kilometres north of the city of Paracatu, in the north western portion of the state of Minas Gerais, Brazil, 230 km southeast of the national capital Brasília (shown in Figure 1). The present day Paracatu mining operation, fully owned by Kinross Gold, through its Brazilian subsidiary Rio Paracatu Mineração (RPM) is designed to be the largest tonnage, lowest grade free milling gold operation in the world.The deposit currently hosts some 1.2 billion tonnes of ore at a grade of ~0.41 g/t gold, hence contains a total gold reserve of over 20 million ounces. At a designed plant throughput rate of 61 Mt/year the mine life goes beyond 2030."

Jan 1, 2011

By Benjamín Leiding Valdés

"Ante la demanda industrial del cobre en el desarrollo minero, se hace necesario revisar su proceso de producción y repercusión a nivel mundial y peruano. Por tanto, el objetivo del texto describe algunos aspectos de su rentabilidad desde 1947 hasta la actualidad. De acuerdo a este último año de estudio, EE.UU. mantiene el liderazgo de producción con 29%, Chile, ocupa el segundo lugar con 14%, Rodesi, en el tercero con 12% y el cuarto lugar lo disputan Rusia y Canadá. Así, la producción norteamericana de cobre al igual que la chilena se ajusta a las demandas de consumo, mientras que la de los tres países restantes va en ascendencia. De otro lado, la mejoría de precio a nivel mundial, permitió que el conjunto de los demás países restantes ocupe el 18% de la producción, destacándose entre ellos Perú, Japón y México, seguidos de Unión de Sud África, Felipinas, Yugoeslaviay Chipre con más de 40 mil toneladas de producción de cobre. Asimismo, de acuerdo al aprovechamiento del plan de extensión, la distribución de la producción mundial del cobre primario ha mejorado tanto que en 1956 sobrepasó el consumo, aunque mantuvo su auge de precio. Sin embargo, en 1958 dicha situación cambió por el agotamiento de las reservas, ocasionando un perjuicio para los primeros países productores y un aumento para los últimos. En este sentido, los pequeños productores se convierten en las fuentes de producción de la última década, ubicando a Chile y Perú como los principales productores en América Latina. La producción chilena proviene en un 90% de su gran minería y en el 10% de su mediana y pequeña minería y sus principales mineras son Chuquiquimata en Antofogasta, El Teniente en O' Higgiins y El Salvador en Atacama. Mientras que la producción cuprífera peruana se ha duplicado en los últimos 10 años, sobrepasando las 65 mil toneladas por año. La gran minería de cobre en el Perú se inicia en los últimos años a través de la explotación del yacimiento minero de Toquepala, perteneciente a la Southern Perú Copper Corporation, estimando una reserva de 500 millones de toneladas de minerales de 1% de cobre por mes. La minería mediana peruana de cobre se encuentra en las minas de Cerro de Pasco y Morococha, en Junín, donde los minerales son concentrados y posteriormente fundidos en La Oroya. En conclusión, tanto Chile como Perú se constituyen como los dos más grandes productores de cobre sudamericanos que contribuyen al abastecimiento del mineral en este continente como en Europa, Estados Unidos y Norteamérica, no solo por sus reservas sino por la bondad de sus yacimientos. ."

Jul 20, 1959

Recovery of Vanadium from Stone Coal Through an Environmentally Friendly Acid Leaching Technology

Sep 13, 2010

Jan 1, 1970

By W Skinner, C G. Kelsey, J R. Kelly

The iron ore industry has reached the end of an unprecedented period of expansion triggered by China’s demand for iron ore. Lower ore prices have led producers to focus on optimising mining operations while extracting the maximum tonnage from the infrastructure presently in place or from projects already underway. A rising global surplus is expected to further force ore prices down and lead to output curtailments, which in turn will help to restore market balance. However, investment in the development of new resources and the development of new infrastructure will inevitably become necessary. Making the right decisions in relation to future processing infrastructure in a climate of uncertain demand and price volatility will not be as straightforward as in the past, where expanding the scale of a proposed operation has been the answer to ensuring economic viability. Overall cost and environmental pressures particularly in relation to wet processing will dominate the decision-making process. IMP Technologies (IMPTEC) has anticipated the need for a dry low cost processing alternative, which can open the way for the development of lower grade magnetite deposits and ensure the sustainability of processing in Australia. The lower grade magnetite deposits are generally fine grained and require grinding to p80 of 30 to 40 microns. Historically, the cost of grinding to these sizes has been and remains a key factor determining the economic viability of a magnetite processing operation. The IMPTEC Super-fine Crusher and Cyclomag Separator are the key components of a proposed radically simplified dry processing alternative, which addresses both cost and environmental issues. This paper reports on the results of pilot super-fine crushing and cyclomag separation test work, focused on supporting the feasibility of the proposed dry processing route for the production of high-grade pellet plant feed from fine grained low-grade magnetic ores.CITATION:Kelsey, C G, Kelly, J R and Skinner, W, 2017. Dry processing of magnetic iron ores – addressing cost and environmental issues, in Proceedings Iron Ore 2017, pp 215–220 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By Lars Arne Granlund

Due to the coarse structure of mining explosives, one has to model a finite reaction zone,contrary to C-J calculations, describing their detonations, i.e they become dependent of diameter and confinement, An effort within the DYNO group has been to investigate if the DSD theory ( originally developed by Bdzil, Stewart / Los Alamos ) can be used to describe major groups of civil explosives.The groups of explosives tested are dynamite, anfo, aluminised emulsion, heavy anfo and straight emulsions.

Jan 1, 1995

By Dae S. Young

The paper point out a new procedure to calculate the volumetric distribution of rock fragments. The method combines the practicality of digital image processing of the rock surface with the theoretical volume calculations based on principles and laws of fractal geometry. The final volumetric distribution curve is compared with the results from traditional sieving indicating close agreement.

Jul 17, 2000

By Oswaldo Carhuancho

El presente trabajo señala la filosofía de trabajo en equipo desarrollada en la mina Pierina, Lima. La política de trabajo se sustenta en el pensamiento de Barrick, donde las prácticas administrativas basadas en la seguridad, salud ocupacional y el medio ambiente repercuten en el beneficio de sus empleados, accionistas y las comunidades en las que opera. Por ello, la primera preocupación de la empresa debe ser el trabajador y no las máquinas, así como la labor de los jefes no se limita a una actitud paternalista, sino a una democrática, de forma que el empleado asume sus responsablidades con seguridad y eficiencia. Como consecuencia de ello, se redujeron la cantidad de hombres-accidentess, se elevó el costo de producción y se redujo, la cantidad de personas en la supervisión de operaciones mina.

Sep 13, 2001

By A. D. Cameron

La voladura es una de las primeras operaciones del ciclo de minado y su impacto es fundamental en la productividad y economía de la mina. Por ello, su diseño y su evaluación de resultados debe realizarse considerando el contexto de la operación minera en su totalidad como en términos de productividad y costo. En este sentido, el presente texto señala algunas de las técnicas empleadas para mejorar la optimización del trabajo de voladura, considerando las herramientas de software utilizadas por el ingeniero de voladura como el análisis del diseño, la predicción y medición de los resultados del disparo. La dificultad estriba en poder relacionar los resultados de la voladura, como la fragmentación, dilución y daños, a los parámetros de productividad tales como: el ciclo de minado, el tiempo de limpieza y la producción de la chancadora, etc.. La poca disposición a utilizar las herramientas de diseño y monitoreo disponibles se relaciona a la dificultad de poder cuantificar el impacto de los malos disparos en la marcha económica de las minas.

May 25, 1998

By D. M. MacHunter, T. Lawson, D. K. Henderson

The development and commercialization of new generation high tension electrostatic separators has provided a basis for simplifying mineral separation plant circuitry. The inclusion of new design features including insulated plate electrodes that have resulted insignificantly improved separation efficiencies in electrostatic separators are described. The increase in separation efficiency has resulted in a reduction in the number of treatment stages required to produce final high grade mineral products. Comparative performance data on different feed types are presented. A comparison between mineral separation plant flowsheets using both conventional and new generation high tension electrostatic separation technology is presented. A 55% reduction in the number of installed electrostatic separators and a 36% reduction in plant area was achieved through the use of this new electrostatic separation technology.

Jan 1, 2003