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By A H. Gray

Gekko Systems Pty Ltd engaged in the test work, design, manufacturing and commissioning of the pre-concentration plant at Silver Standard Resources Inc’s Pirquitas mine in the north western Jujuy province of Argentina. Testing of the ore at coarse feeds of between 2 and 12mm returned probable recoveries of up to a total of 95% silver into 50% of the mass fed to the InLine Pressure Jigs (IPJ’s). The plant has been designed and built based on the test results to include a preparation screen to bypass the fines that are naturally higher in grade and repulping of the coarse which is then pumped to three parallel trains of 2-stage IPJ roughing-scavenging. The target 50% yield to concentrate passes over a dewatering screen and the solids are returned back to the mill feed conveyor. The IPJ tails are transferred to a dewatering screen and solid rejects are stockpiled off the end of a transfer conveyor. All dewatered underflow products are processed via hydrocyclones to recover dirty water for use back into the IPJ circuit and return entrained fines to the fines bypass line.With the sulphide orebody being processed, the results from operations to date have shown that plant performance is matching the original laboratory sulphide ore testwork data. The objective of the pre-concentration step is to both reject gangue and achieve grades between 300-400g/t Ag to the float circuit as flotation recoveries are maximised within this range. The plant currently achieves overall upgrades of approximately 150% of feed grade with the IPJ only circuit producing an average 180% increase from calculated feed grade.

Aug 8, 2011

By Wesley, Worner H

During the meeting of the Institute last year at Port Pirie, the opportunity was taken to sample the lead bullion coming from the blast furnace and various stages during the refining process. Also, in the desilverising section, the upper zinc rich phase was sampled as the silver content built up and in the cupellation operation a series of samples was taken as the silver content of the bullion increased. In these two cases, the samples were taken under the supervision of a member of the staff of the Broken Hill AssociatedSmelters.In the following account of the microstructure of the samples taken, only the main phases present have received attention. In this connection deduction from phase diagrams of binary alloys has been used in conjunction with the assays carried out on duplicate samples taken at the same time as those for micro examination.

Jan 1, 1938

By R. Singhal

Canada's coal production is approximately 65.4 million tonnes of which 95 % is produced by surface mining methods mostly from the three Western provinces (British Columbia, Alberta and Saskatchewan). The mines are highly mechanized; productivity gains during the past few years have ranged from 60 -80%. Truck/Shovel methods are common although Saskatchewan lignite is almost exclusively mined by draglines. This paper provides an overview of Canadian Coal mining industry vis a vis surface mining. Emphasis is on application and utilization of mining equipment and associated mining methods.

Jan 1, 1994

By P R. Denize, V S. Wein

A brief review of the Waipipi Iron Sands Limited company history and operations over the past ten years is made along with a summary of the benefits of this mining company to New Zealand. Land rehabilitation procedures in coastal dune lands are described in detail and brief mention is made of a study of animal health and copper uptake. The paper concludes with a summary of the increased emphasis on agronomy and restoration as the mining operation commences dredging in a better class of grazing land.

Jan 1, 1981

By George A. Costello

A theoretical analysis is presented for the static and dynamic response of wire rope in deep-shaft mining operations. Expressions for the stresses in the individual wires of complex wire ropes are derived, and specific results for simple strands, 7x7 ropes, 6x 19 Seale ropes both with and without internal-wire-rope cores, and 6x25 filler-wire ropes both with and without internal-wire-rope cores, are presented for the case of ropes subjected to a combination of axial loading and bending over a sheave. Consideration is also given to the dynamic overloading associated with certain mining operations, such as dumping ore into a suspended skip and accelerating a fully loaded skip upward. Experiments to determine the axial stiffness of wire rope are described. Factors affecting the service life of wire rope, such as residual stresses, contact stresses, and fatigue behavior, are discussed. Specific research areas in need of further investigation are identified.

Jan 1, 1983

By G. Naranjo

Dada la demanda de nuevos materiales como su resistencia a altas temperaturas, la empresa minera del siglo XXI se perfila no solo a la producción de metales, sino a la extracción de sustancias no metálicas. En este sentido, la actividad minera no metálica en el Perú, se encuentra en un estado incipiente de desarrollo, en tanto existe una desinformación sobre la tecnología empleada en la extracción y las especificaciones para la industria minera. Por tal motivo, el objetivo del presente texto es el desarrollo de la minería metálica a través de la evaluación de las características de los recursos no metálicos, selección de métodos, técnicas apropiadas y control de calidad, a fin de difundir la importancia de dicha actividad y la competencia a nivel internacional.

Nov 24, 1993

By Elisa Alonso

Recycling is generally a more sustainable alternative to landfilling. Its financial costs however, do not always justify its practice, especially in the short term. As a result, even for precious metals such as platinum, significant amounts can end up unrecovered. In considering risks of materials scarcity for firms that require platinum and platinum products, this paper examines how recycling provides additional benefits as a risk-mitigating strategy against scarcity. The experimental platform for this examination is a System Dynamics simulation model that strives to capture the dynamics of platinum market supply, demand and price. The detailed structures of supply and demand are key features of the model. Results show that since the secondary supply of platinum depends on a supply chain separate from primary extraction, recycling can diversify the risks of primary supply instabilities and reduce the impact of price fluctuations upon firms.

Jan 1, 2009

By Anthony Iannacchione

Designing coal pillars to provide resistance against overburden loads has long been an aim of rock mechanics engineers. The need for accurate pillar strength models has become more urgent as greater overburdens are encountered and pillar sizes grow larger. Current pillar design models differ widely in their predictions of the trend in pillar strength with increasing pillar width-to-height ratio. The goal of this paper is to evaluate current pillar strength theories, using a comprehensive data base of stress measurements from coal pillars. The stress measurements indicate that coal pillars maintain relatively high stresses near the ribline, and that the stress gradient within the yield zone can be approximated as a straight line. Several problems are identified for further research, including calibration procedures for different types of stress cells, strain softening behavior in the yield zone, and measurement of stresses in the cores of very wide pillars.

Jan 1, 1992

By C. Musingwini

Traditionally, mineral reserves management at most underground mines in Zimbabwe focus on maintaining large mineral reserves so that the time between development and production is as long as possible. Historical data at Shabanie mine, a Zimbabwean sub-level caving underground mining operation, confirms this practice. However, the high cost of underground development means that the luxury of large buffer mineral reserves cannot be justified. Furthermore significant increases in the costs of production, exacerbated by the current unfavourable economic climate, make the wisdom of extending development workings well ahead of use questionable. Poor ground conditions at Shabanie mine, mean that some development ends have to be re-mined two or three times due to partial or complete closure between the time they are mined and the time they are utilized. In order to reduce the inordinately high support costs associated with closure of development ends a new ?just-in-time? (JIT) approach that provides development ends as and when they are needed, has been adopted. Accordingly a model to determine an appropriate ?just-in-time? rate of development has been created. The JIT development model indicated that the mine could reduce development rates from 330 m/month in 2001, to 160 m/month in 2002 and achieve savings of about 50% on annual support costs, but still assure customers of a long-term product supply. The mine accepted the model in November 2001 and began implementing it in 2002. Results of the implementation will be reviewed in 2003.

Jan 1, 2003

By J Col, D La Rosa, W Valery, A Jankovic

Metso Minerals Process Technology Asia-Pacific and South America (MMPT) has been working with operations around the world to increase their efficiency through æMine-to-MillÆ or Process Integration and Optimisation (PIO) projects. These projects have delivered significant improvements in mine efficiency, mill throughput and reduced operating costs at mines around the world. The MMPT methodology involves rock characterisation, site auditing, data collection, modelling/simulation and implementation of integrated operating and control strategies on site. This results in significant benefits to the operations û for example, 5 to 20 per cent increases in concentrator throughput have been measured. MMPTÆs rock characterisation utilises simple and inexpensive measurements that can be performed by trained site personnel. The advantage of these measurements is that a large amount of data can be collected in a very short timeframe, as the samples do not require shipping to an outside laboratory. Typically, a PIO project starts with a site visit to perform blasting and process audits, collect high quality data including measurements of run-of-mine fragmentation and survey data around all crushing and grinding circuits. These measurements are combined with rock characterisation and the definition of strength and structure domains to model the complete production chain. Site-specific models of the blast fragmentation, crushing, grinding and flotation processes can then be developed. This proven methodology has applications ranging from greenfield projects to long-standing operations with AG/SAG or conventional grinding circuits. Process improvements can be higher mining productivity, higher mill throughput, decreased overall operating costs and higher flotation or leach recovery. This paper discusses a recent application of PIO conducted at a large open pit operation in South America and emphasises the potential that every operation has to ædo more with what they haveÆ.

Jan 1, 2007

By Juan Carlos Ramírez

En los últimos años se desarrollaron sistemas para la generación de paredes finales en yacimientos de cielo abierto y así proveer la pared adecuada a los parámetros que alimentan el sistema. Por tal motivo, el objeto del texto es realizar un estudio comparativo entre los dos sistemas de generación de paredes finales: Pushbacks y Whittle 3D. La aplicación de ambos sistemas se ejecutó a través de dos etapas en la mina Cuajone donde el sistema Pushbacks guió el diseño de paredes finales de mina desde 1984 hasta 1989. Mientras que el segundo, se utilizó desde 1989 hasta la actualidad puesto que es un sistema optimizador computarizado que permite obtener paredes finales óptimas en yacimientos explotables a cielo abierto de forma segura.

Apr 1, 1991

By S. Kawatra, K. Lewandowski

Heap leaching efficiency is reduced by poor solution flow characteristics (channeling and ponding), which result from fines migration. Agglomeration of the ore can immobilize fines, but copper leaching requires an acid-resistant binder to stabilize the agglomerates. Until now, there has not been a satisfactory way to evaluate whether a binder was effective, other than squeezing a handful to see if it “feels right”. We have developed procedures to quantitatively determine whether a binder gives good performance in an acidic solution, and have identified several binders that will be suitable for copper heap leaching.

Jan 1, 2007

By Afonso Rangel Garcez de Azevedo

Este trabalhou lidou com a avaliação de amostras de tijolo de argila para alvenaria estrutural com adição de resíduo cerâmico cujas dimensões nominais são 11,5x39,0x19,0 cm. As amostras foram queimadas nas temperaturas 700°C e 800°C. Elas foram coletadas em uma fábrica de cerâmica vermelha em Campos dos Goytacazes, RJ, Brasil. De um lote, a amostra contendo 20 tijolos de alvenaria já queimada em seu forno a 700°C foi coletada, e também a amostra contendo 20 tijolos de alvenaria do mesmo lote secos apenas pelo ar, que foram queimadas em um forno de mufla a uma temperatura de 800 ° C. As amostras foram submetidas aos testes recomendados pela ABNT NBR 15270: 2005 para determinar suas propriedades geométricas, físicas e mecânicas. A ABNT NBR 15270: 2005 recomenda formulações específicas para determinar a resistência à compressão característica (fbk) da alvenaria de tijolos de argila que, para ser classificada, deve ser de pelo menos 3 MPa. Portanto, também usamos o Método Gráfico de Probabilidade e o Método da Máxima Verossimilhança para estimar os parâmetros de distribuição para comparar os resultados obtidos nos testes realizados.

Oct 30, 2017

Detrital gold in the Greymouth-Hokitika area has been won from: (a) gravel of the Pliocene Old Man Group, (b) glacial outwash gravel of Middle and Late Quaternary age, (c) raised shoreline deposits of Middle and Late Quaternary age, (d) deposits resulting from the erosion of (a) to (c). The source of the gold was probably widely dispersed quartz veins in great thicknesses of greywacke and low-grade schist eroded from east of the Alpine Fault, with a contribution from veins in Greenland Group greywacke in the south. At times of high interglacial and post-glacial sea level, gold was concentrated along marine shorelines, and subsequent progressive uplift has resulted in a set of sub-parallel beach leads up to 100 m above present sea level. During glaciations, gold was concentrated in outwash streams close to moraines, especially where ice forming one moraine penetrated and destroyed an older one. Worked deposits in the Old Man Group may also be associated with glaciation. Apart from workings that are essentially extensions of past workings, significant new prospects may depend on inferences as to where prospective deposits are completely obscured by younger ones.

Jan 1, 1996

By R. J. Miller

The current National commitment to expanding the human presence into the solar system will clearly require major facilities in Earth orbit or possibly on the moon. Such facilities will need large amounts of materials for structural modules, life support, propulsion, and shielding. The heavy transportation costs in fuel required to lift materials from the Earth's surface make a terrestrial-based space system inherently inefficient. A more cost-effective approach would be to provide as much of the required materials as possible from other bodies in space not having the high cost of Earth launch. This paper identifies potential targets for space-based resource utilization, constraints on exploitation, and relative benefits of various sources.

Jan 1, 1992

By Dongok Kim

Regardless of the advantages of the Friction Stir Process (FSP), for age-hardened aluminum alloys, the mechanical properties such as hardness in the stir zone decreased after FSP due to the growth or dissolution of strengthening precipitates. Here, as a new technique, FSP was introduced to alloy copper nanopowders in Al7075 T651. Mechanical properties of copper nanopowder- alloyed Al7075 T651 together with micro and nanostructures were compared with those of as-FSPed Al7075 T651 using SEM, TEM, and Vickers hardness testing to understand structure-property relationships. It was observed that Vickers hardness of the stir zone in copper nanopowder alloyed Al7075 T651 increased by 20% compared to that of the heat affected zone, while the as-FSPed samples did not show a noticeable increase in hardness in the same zone. Xray mapping showed traces of copper nanopowder after the process. TEM is being used to verify if there was CuAl2 formed in the copper alloyed sample.

Jan 1, 2006

By R. P. H. Willis

Uranium is back on the radar. Uranium has always been a controversial metal, from its role in the arms race to its claim to be the only viable alternative to fossil fuel. This paper will cover its properties and use, its occurrence and production in South Africa, the current market drivers and its future role as a primary energy fuel. It will highlight the difference between uranium used to make a bomb and uranium used in a power station. The recent significant uranium price rise will be put into context of the market drivers including geopolitical issues. Planned expansions in nuclear power station capacity will be reviewed, as will new mine production. Future demand will also be speculated on.

Jan 1, 2006

By Y. Breau, F. Robichaud

The Expert System implemented at the East-Malartic mill controls a copper flotation circuit while taking into account the profitability of the operation. Treating a copper gold ore, the flow sheet integrates a flotation step followed by cyanide leach circuit. The Expert System calculates the actual net smelter revenue of the flotation circuit, accounts for the operating cost of the cyanidation circuit and defines optimal metallurgical operating targets to optimize the overall economics. To be realistic, probability factors and circuit diagnostic analysis are integrated in the operating target selection. The Expert System has proved to be successful, robust and flexible. It resulted in a copper concentrate grade increase of 1% while maintaining recovery. The use of the expert system also gives plant personnel good training procedures and promotes interaction with mill operator.

Jan 1, 2002

By John C. Machisak

INJURY EXPERIENCE AND EMPLOYMENT DATA on all stone quarries and associated plants in the United States are presented in this publication for the calendar year 1959. Such related operations as the manufacture of cement and lime and rock dressing are included. Data on clay and sand and gravel operations are not included and will be found in other Bureau publications on injuries and employment. The Bureau is authorized to make requests for such data and the information voluntarily submitted by the operators contributes to the promotion of safety in the quarrying industry. Every effort has been made to make this canvass as complete as possible. Data for production workers and office employees at the quarry site are included.

Jan 1, 1963

By John C. Machisak

INJURY EXPERIENCE AND EMPLOYMENT DATA on all stone quarries and associated plants in the United States are presented in this publication for the calendar year 1959. Such related operations as the manufacture of cement and lime and rock dressing are included. Data on clay and sand and gravel operations are not included and will be found in other Bureau publications on injuries and employment. The Bureau is authorized to make requests for such data and the information voluntarily submitted by the operators contributes to the promotion of safety in the quarrying industry. Every effort has been made to make this canvass as complete as possible. Data for production workers and office employees at the quarry site are included.

Jan 1, 1963