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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 C. Ogasawara

This document describes the direction and progress of the Bureau of Mines Oil Shale Mining Environmental Research Program as of January 31, 1979. It is aimed at focusing the Bureau's role in environmental research supporting oil shale development with respect to the activities of other involved government agencies and private industry. Environmental considerations in oil shale extraction, such as ecological disturbances, health and safety hazards, waste management, and socioeconomic impacts, are discussed along with the type of research known to be planned by organizations to ameliorate these problems.

Jan 1, 1979

By John P. Borovsky

A 3-year study was conducted to evaluate the problems and benefits of using vegetation to stabilize tailing from a potential Minnesota copper-nickel milling operation. The project consisted of three separate investigations: a waste characterization study, a greenhouse study and a field study. With few exceptions, the physical and chemical characteristics of the tai ling were found to lie within the range of properties of Minnesota soils. The tailing lacks organic matter; is deficient in nitrogen, phosphorus and potassium; and may contain elevated levels of soluble salts and heavy metals, particularly copper and nickel. Numerous grasses, forbs and woody plants will tolerate the tailing as a rooting medium. Peat incorporation and topsoil dressing provided few benefits to the revegetation process which were not provided by a fertilizer application. With fertilization, grass/legume production in the tailing was comparable to local agricultural yields. Concentration of heavy metals in grasses grown in the tailing were generally below suggested tolerance limits for plants and animal forage. Legumes tended to accumulate higher concentrations of copper and nickel, and metal uptake of most plants was positively correlated with rate of fertilization. Tailing drainage water contained elevated levels of heavy metals, and establishment of vegetation had little effect on the quantity and quality of tailing drainage water. However, topsoil dressing significantly increased drainage water volume when compared to unvegetated control plots. Copper-nickel tailing revegetation recommendations were developed.

Jan 1, 1983

Maintaining high carbon activity is vital to the efficiency of any Carbon-In-Leach or Carbon-In-Pulp process. Reduced activity can lead to longer residence times or gold losses in the tails. Regenerated carbon from the CIL circuit at Macraes Gold Mine was analysed for kinetic activity and composition over a 15 month period. An increase in kinetic activity during the time period was recorded, which was linked to reduced Na and Ca loadings. A laboratory simulation of the loading, stripping and regeneration of gold was developed and tested. Kinetic activities were obtained for synthetically fouled carbons following three circuits of the laboratory simulation. It was shown the competitive gold adsorption ability of xanthate fouled carbon (previously reported as a serious deactivator) could be significantly recovered following effective thermal regeneration. This ability was maintained in a subsequent circuit loading.

Jan 1, 1993

By Alfred Wild

The Kraftile Co. plant, Fremont, Alameda County, Calif.--the largest producer of glazed, structural wall units west of the Rocky Mountains-- maintains modern processing facilities to evaluate and blend a wide variety of clays from several sources to produce quality products. The report desribes the prospecting, exploration, and test methods used to locate raw material sources and covers processing methods, cost factors, and trends. Also, the geologic and ceramic factors are considered in a general discussion of the economics, potentials, and requirements of clays as raw materials for ceramic tile manufacturing.

Jan 1, 1963

By H. Saroglou

The anisotropic behaviour of Athens Schist has been brought out through the testing of specimens with varying orientation of schistosity with respect to the major principal stress under uniaxial, triaxial and dynamic conditions. A large number of results from tests on intact rock specimens of the Athens Schist were statistically analysed and evaluated.

Jan 1, 2004

By J. R. Thoenen

In the summer of 1937 the authors began a series of time studies of the various processes employed in the production of crushed stone. These studies, made at quarries scattered over the eastern and southeastern parts of the United States, have not been completed, but to make results available to thee industry as early as possible it was decided to publish summaries of the studies made to January 1, 1939, as a series of progress reports. The first of these reports dealt with power-shovel loading and was issued as Report of Investigations 3461 in September 1939. The present circular discusses analyses of the time Studies of the haulage systems at the same quarries. OBJECT OF STUDY The pressure of business problems frequently requires the entire attention of quarry management and in consequence internal plant economies often are neglected, Also, operating officials absorbed in their local problems are prone to overlook possible economies that would attract attention immediately were they critically examining another plant. The authors felt that similar studies of many plants by impartial engineers -would disclose possibilities for cost reduction or greater efficiency in internal plant processes.

Jan 1, 1939

By M. Nyoka

Consideration of the economic, environmental, and social impacts associated with the life-cycle of a technology is of increasing importance for decision-making in industry. It has been suggested that economic assessment of technology deployment projects requires the translation of associated environmental effects into monetary values. This paper introduces an approach for identifying and evaluating environmental damage in monetary terms. The approach groups the environmental impacts associated with a technology life-cycle system into four main criteria: air, water, land, and mined abiotic resources. The valuation of the impacts on the resources consists of an economic cost benefit analysis (CBA) procedure that comprises four steps: the compiling of an impact inventory, a monetary valuation of the inventory, discounting, and a risk/uncertainty analysis. The monetary valuation step for impacts on air resources is primarily based on published externality costs for Europe and the United States, which are adopted and converted to reflect the South African context. Local opportunity costs are utilized for the other resource criteria. The damage costs are transformed into South African Rand at 2005 prices. The paper demonstrates how the approach may be applied in the assessment of projects in the metallurgical industry. Shortcomings in the approach are identified. For example, not all of the aspects that are considered necessary to assess environmental performances comprehensively can be valued in monetary terms. Also, certain values, specifically those pertaining to opportunity costs, need to be determined on a case-by-case basis. Furthermore, the uncertainties associated with the indicators obtained may strongly influence the usability of the results of an environmental performance assessment, e.g. future damage costs will change with fluctuations in the markets. It is concluded that although such an approach has merit in increasing the understanding of the potential financial implications of a technology?s environmental performance, further research is required to improve the approach described if it is to be used further in the South African metallurgical industry. Damage cost estimates that are specific to South Africa need to be developed to reduce uncertainty, and the combination of both quantitative and qualitative approaches is recommended for comprehensive sustain-ability decision-making.

Jan 1, 2007

By Fernando Altamirano

Dado que en las unidades mineras existen problemas respecto al manejo de la información relacionada a la seguridad, salud e higiene tales como que los reportes enviados a las autoridades competentes (MEM, DGM, DGAA, OSINERG, DIGESA, etc.), se hacen en forma manual, generando una revisión y conteo previo tedioso y donde no existe una clasificación o estructuración de la información. En ese sentido, se plantea la utilización de las herramientas tecnológicas modernas para optimizar la administración de la información generada en las operaciones de forma diaria. Este sistema está desarrollado bajo una arquitectura Cliente/Servidor con bases de datos que soportan SQL., que se asegura una solidez en la generación de tablas relaciónales, un desarrollo práctico de las pantallas de entrada, flexibilidad para generar reportes y capacidad de expansión e integración a otras aplicaciones, donde se busca que el usuario se sienta a gusto utilizando su interfase full Windows diseñada para efectuar los registros y operaciones de manera intuitiva y versátil.

Aug 25, 2002

By R. Patel, D. R. Taylor, P. M. Varley

In-situ measurements of ground stress were made from surface boreholes, using overcoring and hydrofracturing techniques, to obtain data for the detailed design of the underground works at Pergau. Unexpectedly low stresses were measured and appeared to correlate with apparent hydrofracturing observed during permeability testing. The low values of the minor principal stress had a major impact on design, particularly of the lining for the pressure tunnel and shaft. Additional hydrofracture tests were made underground during construction of the low- and high-pressure headrace tunnels and the pressure shaft, to define the vertical reduction in the minor principal stress with overburden. These data were then used to locate and design the steel and reinforced concrete linings

Jun 19, 1905

By Brian Reid

"This paper studies the progress made by hydraulic shovel manufacturers over the last few years, particularly in the areas of productivity increase and operating cost reductions.Five years ago, it was widely considered that the unit production cost for a hydraulic shovel in a mining application was double that of a cable shovel in the same application. The hydraulic machine manufacturers have taken up this challenge, and modern improvements in design, coupled with changes in maintenance techniques, have narrowed the gap to the point where it is valid to ask the question ""will the cable shovel exist in ten years' time?"".Historical BackgroundThe history of the cable shovel goes back to the early 19th century and the industrial revolution. Early machines were steam-powered and ran on rails.The ""power shovel"" and the ""dragline"" were the only mechanical means of mass excavation until the early 1950s. Rail-mounted units gave way to crawlers, which increased flexibility considerably. Some shovels were redesigned as backhoes, and some became extremely large when designed as stripping shovels primarily used in North American coal mines.In the early 1950s growth in hydraulic technology spawned the introduction of the hydraulic excavator, which soon began to replace the smaller cable shovels and backhoes used in the construction industry. They were completely self-contained with either a gasoline or diesel engine and, being much lighter, were more readily transportable.As the excavators grew in size from its early models of 0.5 m3 or less, many of the cable shovel models were discontinued. This was not surprising for several reasons, but the most obvious is that both were often made by the same manufacturer."

Jan 1, 1988

By G. R. Hopkins

The average heat requirement per barrel of crude processed in the United states rose from 555,000 B. t. u. in 1939 to 579,000 B. t. u. in 1940, although crude runs increased from 1,237,840,000 barrels to 1,294,162,000 barrels in that period. Thus the almost invariable rule that the average amount of heat needed to refine a barrel of crude oil declines when total crude runs to stills increases was broken. (See fig. 1.) The reasons underlying the apparent loss in fuel efficiency in 1940 are quite obscure. There is little question but that the principle of heat exchange, the most important fuel saver, was used as extensively in 1940, as in 1939. A few companies replaced purchased power with electricity made at their plants, but for the country as a whole purchased electricity increased 7 percent, as compared with a 5-percent gain in crude runs to stills. Furthermore, the premise -the more complex the products the more fuel required -does not hold, as the yield of ?complex" products, including gasoline, declined in 1940.

Jan 1, 1942

By Bruno Bussière, Guosheng Zhan, Michel Aubertin, Vincent Martin, Robert P. Chapuis

The study evaluates the hydrological behaviour of exposed and covered waste rock dumps. The objectives were to determine the major factors influencing unsaturated flow in waste rock dumps and covers, and to improve the in-situ, laboratory and numerical modeling characterization methods. Using material properties obtained from in-situ and laboratory tests, waste rock dumps of different configurations, with and without covers, were modeled. It was found that a properly designed “Store, divert and release” (SDR) cover allows most of the water to be diverted downslope and discharged outside of the waste rock dumps. The SDR cover seems to work efficiently even in extreme storm events. The numerical modeling results show that the unsaturated hydraulic properties (e.g. air entry value and water entry value) of the materials largely control the infiltration of water into waste rock dumps.

Jan 1, 2005

By Mohammad Nasim

Vertical expansion of existing structures frequently requires foundation retrofitting to enhance the capacity of existing foundations for supporting additional loads. Owing to their small diameter, a variety of suitable drilling methods available for installation, and smaller installation equipment capable of operating under limited headroom conditions, micropiles are often preferred for foundation retrofitting. This paper presents a case history demonstrating application of micropiles to underpin the existing foundation of the Washington D.C. Children?s National Medical Center (CNMC) for its future expansion. Located at 111 Michigan Avenue in northwest Washington, DC, portions of the hospital currently extend five stories above grade and three levels below-grade as parking garages. The hospital intends to expand the surgical wing up to the current build out (five stories) above the remaining portion of the existing parking garage. The original foundations consist of 80-ton Raymond Step-Tapered piles. New loading on the foundations required each Raymond pile to be capable of supporting 150 tons. Results from quick load tests on existing piles indicated that two entire column lines (Column Line A and B) would experience loads beyond their capacity, requiring enhancement of the existing foundation at these locations. The design and construction of the foundation upgrading work was particularly challenging due to various project constraints related to a high groundwater table, micropile installation under limited head room, and ensuring that the parking garage remained fully operational for the entire duration of construction. The paper presents the challenges faced during testing of existing foundations amid a high groundwater table, design developments of underpinning options to support the additional column loads, difficulties and challenges encountered during installation of the micropiles and construction of the micropile pilecaps, and value engineering options developed during various phases of the project. Understanding that micropiles are often a preferred option for foundation retrofitting, the case history is expected to provide a baseline design approach and innovative solutions to typical challenges faced during construction, thereby reducing potential cost overruns during design development and construction of similar future projects.

Jan 1, 2008

By H. Saroglou

Anisotropy is a characteristic of intact foliated metamorphic rocks (slates, gneisses, phyllites, schists). Testing was used to establish the anisotropic behaviour of selected gneissic rocks. The effect of anisotropy on various mechanical properties (strength, deformation) and dynamic properties (wave velocity) was examined. The rock samples were also tested at successively higher confining pressures in order to evaluate the effect of anisotropic behaviour at high overburden pressures.

Jan 1, 2004

By Basil Dimitriades

The roles of hydrocarbons and nitrogen oxides in smog formation were investigated by the Bureau of Mines. Samples of automobile exhaust with varying HC and NOx levels were irradiated in a smog chamber under conditions that resulted in smog levels similar to those observed in the atmosphere. Results were used to define the patterns that describe the dependence of a number of smog manifestations on HC and on NOx. Using these dependence data and some simplifying assumptions, estimates were made of the ranges within which HC and NOx must lie in order to obtain specified levels of air quality.

Jan 1, 1970

The accurate estimation of ore reserves along with capital and operating costs are two key components to the successful outcome of any feasibility study. In recent years, there have been many project failures caused by improper estimation of ore reserves. The accurate estimation of ore reserves for any deposit relies heavily on understanding its geology and underlying assumptions unique to the estimation techniques being used. The assumptions unique to commonly used traditional and geostatistical reserve estimation technique will be reviewed. The shortcomings of the estimation techniques and their possible impact on a given project's economic outcome will be discussed. The latest developments in geostatistics in overcoming existing reserve estimation problems will be presented.

Jan 1, 1994

Your thoughts on the current status of the global minerals industries? The global economic, technological, social and political changes of the last two decades of the 20th century resulted in the emergence of a restructured minerals industry. This industry is now based on a new cost-cutting philosophy; utilization of modern technology; productivity gains rather than production tonnages; diversification of mineral markets; and globalization of exploration, mining and processing. Quantity and tons used to be the focus. The emphasis today is on remaining competitive in the marketplace by lowering per-unit production costs as much as possible. What factors and trends will impact the minerals industries in this, the 21st century? A number of parameters will impact minerals operations and shape the future sustainability and growth of the minerals industries. Increased demand for minerals will be accompanied by the demand for technical advancements. We will also see a continued emphasis on health and safety, environmental stewardship, and education and training. Let me elaborate.

Jan 1, 2002

By A. R. Kiani-Rashid

Controlled graphitization has become known as a practical method for improvement of wear resistance and machining properties in steels. In this paper, the effect of heat treatment on microstructure of CK45 steel has been investigated. Austenitising was carried out at 920°C for 5 hours. Besides, isothermal transformation was conducted at 750°C in the time range of 1-20 hours. The microstructure of the steel considerably changes by this heat treatment process which exhibits the effects of temperature, appropriate austenitising duration and isothermal transformation. Conducted experiments show a suitable distribution of semi-spherical graphite particles especially on the surface of the steel. Also, analyses demonstrate that the amount of formed graphite in the austenitising temperature 920°C is more than graphite in single heat treatment temperature of 750°C.

Jan 1, 2010

By Carlos G. C

Geological mapping in various parts of Australia is revealing a number of regional associations of mineralizations with particular persistent stratigraphic horizons. Such associations have been found in the Broken Hill district of New South Wales, in the Nairne district of South Australia, in the Mount Isa district of Queensland, and in the Cloncurry district of Queensland. The question has arisen as to whether such mineralizations are of sedimentary origin, syngenetic with the enclosing formation, or whether they are of epigenetic origin, and reflect the selective hydrothermal mineralization of favourable beds on a regional scale.The purpose of this investigation is to test the use of sulphur-selenium ratios as an objective method of distinguishing between suphide deposits or sedimentary or supergene origin, and sulphide deposits of hydrothermal origin, with particular application to the districts mentioned. At the same time much data has been accumulated as to the selenium content of Australian sulphide ores. The possible use of sulphur-selenium ratios for this purpose was first demonstrated by Goldschmidt and his coworkers (1933; 1935), and later by Carstens (1941). Goldschmidt and Strock (1935) found that pyrite of sedimentary origin had a sulphur : selenium ratio of the order of 200,000 or more, whereas pyrite of hydrothermal origin had a sulphur: selenium ratio of 10,000 to 20,000. Carstensfound that sedimentary pyrite deposits in Norway contained less than 1 g. Se per ton, whereas hydrothermal pyrite deposits contained 20 to 30 g. per ton.

Jan 1, 1954