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By H. Britton

This bulletin is the seventh in the series of petroleum bibliographies published by the Bureau of Mines, Bulletins 149, 165, 180, 189, 216, and 220 being compilations for the years 1915, 1916, 1917, 1918, 1919-20, and 1921, respectively. In this bulletin the same general plan of classification of references has been followed, but several additions have been made. ACKNOWLEDGMENTS Acknowledgment is made to the following organizations for the use of their libraries in the preparation of this bulletin: University of California, Stanford University, California State Mining Bureau, Union Oil Co. of California, Standard Oil Co. of California, and the Mechanics Mercantile Library of San Francisco; acknowledgment for their assistance is also made to H. H. Hill, C. P. Bowie, A. L. Foster, M. J. Gavin, H. C. Miller, E. B. Swanson, and Miss Louise Janssen, all of the Bureau of Mines, and to Miss Elizabeth H. Burroughs of the Union Oil Co. of California.

Jan 1, 1929

Development of Underground Gold Processing Plants Underground gold processing plants have potential advantages over traditional surface installations related to a smaller environmental footprint, reduced capital and mining costs, improved security and increased value of the product delivered to surface. The concept of processing gold ores on the surface is the traditional paradigm. A process of pre-concentration of ore underground is likely to result in a major shift in operating costs. In particular, run of mine ore or a large proportion of it will not need to be transported to the surface. As a result, environmental and financial benefits are likely. Underground plants are likely to be pre-concentration systems where the process product is a high-grade concentrate and tailings for stope backfill. Units will be either static or modular. Concentration methods will be gravity and/or flotation or leach based. This paper discusses the development underground gold plants from early concept, through to the world's first operational unit, a newly commissioned unit and the technical basis of a fully modular system.

Sep 13, 2010

Suggestions have been made at various times that there may be a recurrence of lodes similar to those at Kalgoorlie in the country to the south of the Golden Mile, but, so far as is known, there has been no geological evidence to support these suggestions apart from the possible extension of the younger quartz-dolerite greenstone in this direction.Geological mapping carried out by the writer in the Coolgardie district in 1946, provided some additional geological evidence to support this claim, and the ideas then held have since been expanded and are now considered to be sufficiently advanced to present them as concrete suggestions. As will be seen from the following pages, the critical area for lode prospecting is Hannan's Lake, where the basement rocks may include younger quartz dolerite greenstone, which, although perhaps distributed over a smaller area than at Kalgoorlie, could, on structural grounds, have a similar fracture system and similar ore deposition.There is little need to stress the importance discoveries in this area would have in prolonging the life of the field, and stimulating the post-war gold mining revival.Previous Work: Only the publications having a direct bearing on the preparation of this paper are given in the list of selected references, but the writer is very conscious of the fact that much other geological work has been carried out in the Kalgoorlie district since its discovery, by the W.A. Department of Mines, by mining companies, and others, all of which has contributed to the present knowledge of the field, and acknowledgment of the value of this work is given herewith. In presenting the suggestions in this paper a broad structural control of ore deposition is assumed, but this has already been established in other parts of the goldfields of Western Australia, including adjacent areas. In the early nineteen thirties, the Western Mining Corporation commenced work on the basis that there was a close relationship between geological structure and auriferous ore deposition, and a similar approach was first made by the Geological Survey of Western Australia in the South Yilgarn in 1935. These ideas were further developed during later surveys, particularly in the North Yilgarn and the Mount Margaret Goldfield.During the Coolgardie Survey in 1946, broad structural mapping was done in greater detail than before, and the structural ideas were implemented and further developed, leading to some success.Other work to which particular acknowledgment is given is that of Stiltwell, Gustafson and Miller, Forman, Prider and Finucane, at Kalgoorlie, and that of Honman in the Kalgoorlie-Coolgardie district, references to which are given at the end of this paper.Valuable constructive criticism of this paper has been given by Professor E. de C. Clarke and Dr. R. T. Prider, of the University of Western Australia.

Jan 1, 1950

Results obtained from small scale tests using Australian tin concentrates indicate that metallic tin containing less than 0·1 per cent iron can be recovered by a two-stage process using hydrogen and make-up chlorine. In the first stage the concentrate is ground,. pelletized, roasted, and reacted at 650°C with HCI and H2 to volatilize the tin as SnOI2. The volatilization reaction is conducted with cocurrent gas and solids flow because it was found that the use of cocurrent flow yielded a solids residue substantially free from FeCI2. The second stage uses a technique termed "reflux reduction" during which the SnOl2 produced by volatilization is reduced by hydrogen to form tin and a gas containing HCI and H2 of sufficiently high HCI tenor for recycle to the volatilization stage. The elimination of tin ranged from 98+ to 99·7+ per cent of the tin from concentrates containing 5 to 50 per cent tin, respectively. The process should be capable of continuous operation, and a tentative calculation has shown ,that a treatment rate of 12,000 tonnes of tin concentrate per year could be obtained in a volatilization reactor 1·1 m in diameter and 6·1 m high. The process may have particular application to finely divided concentrates containing less than 20 per cent tin.

Jan 1, 1974

Cobalt/tungsten mineralization at Mt. Cobalt, located 170 km southeast of Mt. Isa in northwestern Queensland, is described. Mineralization occurs in the Kuridala Formation of the Mary Kathleen Group, which is composed dominantly of pelitic schists, carbonates and acid and basic volcanics.Rocks in the region are metamorphosed to amphibolite facies and affected by two generations of tight to isoclinal folds and a third, more open generation of folds. The region is divided into three meridionally trending belts on the basis of structural style, with mineralization concentrated in the central, more highly strained belt.Deformation and metamorphism is probably younger than 1670 m.a., and the rocks are intruded by granitic rocks dated at 1509 ± 22 m.a.Mineralization occurs in shear zones at the contact between an amphibolite and enclosing pelitic schists, and within the amphibolite itself. Mineralization consists of cobaltite and scheelite with lesser chalcopyrite, pyrite, pyrrhotite, i1menite, allanite, xenotime and apatite. The mineralizing event involved addition of K, Cl, CO2 W, As, Cu, Ni, Au and rare earths and depletion of Ca and Na. It altered a hornblendeandesine/labradorite host assemblage to a biotiteoligoclase/andesine-scapolite assemblage. Though tourmalinealteration also occurs, it is probably not related to mineralization.It is concluded that the mineralization and alteration assemblages formed by reaction of saline fluids with amphibolite close to the peak of amphibolite facies metamorphism.The fluids are probably metamorphically derived, and their movement was channelled through high strain zones in the sequence. The material carried by the fluids was derived from the metasedimentary/metavolcanic pile as a whole.Other deposits in the Mt. Cobalt-Selwyn area have characteristics comparable with Mt. Cobalt, and the mechanism for the genesis of Mt. Cobalt may have applications at other areas in the region.

Jan 1, 1983

By L Abrahamsson

This paper describes results from a gender study for a new mine in Pajala, a small community in northern Sweden. Using a gender perspective, the study examines migration, education, local culture, the labour market, and work organisation as problems and opportunities in the regional context for the planned mine. The most obvious ‘gender issue’ for the Swedish mining industry is the very low percentage of employed women, which is even lower among mining workers. To recruit the best people, a company actively needs to attract both women and men; however, the mining companies find it difficult to recruit women as cultural, labour market and educational traditions as well as the mining companies’ own cultures often make it difficult for women to find work in the mining industry.The Torneå river valley, the region surrounding Pajala, has a gender-segregated labour market and gender-stereotyped culture and few young women live in this traditional and oldish region. Many young people leave the region and this is especially true for women. Compared to the rest of Sweden, there is a low educational level, especially among the men. In the mining companies, as in many other male homosocial workplaces, the workplace culture has strong connections to a certain type of traditional masculinity (laddishness, a kind of ‘macho-style’) and for a long time this has excluded women. ‘Gender’, however, is not only a question of recruiting women to a male-dominated industry. An organisation that discriminates according to gender can become inflexible, hindering communication, learning, innovations and change processes. In mining companies, this can manifest itself in hesitant attitudes among the miners about safety as well as organisational and technological development.This study found that companies establishing a presence in this region should develop a strategy for how to deal with and manage the risks and opportunities in the surrounding society (the regional culture) as well as inside the company (the mining culture). This need to be strategic will also be required of future mining companies as they will face higher demands on safety, gender equality, and technology to become modern, efficient and lean organisations.

Nov 22, 2011

The selection of Sydney and Port Kembla for the First Ordinary Meeting of the Institute for 1938 was, no doubt, a recognition of the celebrations marking the 150th Anniversary of the first settlement of this country. In selecting a theme for my Presidential Address, I propose to depart from the precedents of my distinguished predecessors, as I feel that this year of celebration is the natural year for a brief review of the history and progress of the Institute.In July, 1892, the Amalgamated Mining Managers' Association of Australasia held its Annual Conference in Ballarat, Victoria, when Mr. Uriah Dudley, who attended as a delegate from Broken Hill, brought forward the advisability of the formation of an Australasian Institute of Mining and Metallurgy. Mr. Dudley was authorised to take such action as he thought fit, and the result was the formation of a Provisional Committee in Broken Hill of men who were mostly members of the American Institute of Mining Engineers. Broken Hill was therefore really the birthplace of the Institute.A circular headed Broken Hill, September, 1892, with the signature of Uriah Dudley, Acting Hon. Secretary, Provisional Committee, which was sent to those likely to take an active part in the formation of an Institute, read as follows:-The Mining Managers' Association of Australasia has suggested that the time has now arrived when an Australasian Institute of Mining Engineers should be established, having objects similar to the American Institute, of which all of the Thirty-one Colonial...

Jan 1, 1938

By Tyler Acorn, Brandon Wilson, Jeff Boisvert

Scenario-level uncertainty is a representation of large-scale differences encountered when considering ultimate mining pits optimized over various subsets of stochastic realizations. Accounting for scenario-level uncertainty allows mine plans to be assessed against several probabilistic subsurface interpretations. Scenario-level uncertainty is found through clustering stochastic geostatistical realizations and optimizing final pits across the realizations in each cluster. Where these pits are geometrically different, plans for each scenario differ. Knowing these differences allows the value of each planning alternative to be assessed based on the value and relative probability of each scenario. These results also facilitate the use of formal decision-making frameworks for planning, leading to optimization that better represents the full statistical characterization of the deposit. An example utilizing this approach evaluates both infrastructure placement and drilling program requirements. In both cases, scenario-level uncertainty improves initial plans by limiting opportunity costs and identifying additional potential.

By Tyler Acorn, Brandon Wilson, Jeff Boisvert

Scenario-level uncertainty is a representation of large-scale differences encountered when considering ultimate mining pits optimized over various subsets of stochastic realizations. Accounting for scenario-level uncertainty allows mine plans to be assessed against several probabilistic subsurface interpretations. Scenario-level uncertainty is found through clustering stochastic geostatistical realizations and optimizing final pits across the realizations in each cluster. Where these pits are geometrically different, plans for each scenario differ. Knowing these differences allows the value of each planning alternative to be assessed based on the value and relative probability of each scenario. These results also facilitate the use of formal decision-making frameworks for planning, leading to optimization that better represents the full statistical characterization of the deposit. An example utilizing this approach evaluates both infrastructure placement and drilling program requirements. In both cases, scenario-level uncertainty improves initial plans by limiting opportunity costs and identifying additional potential.

By M. Perolo, A. Contini, E. Ramelli, G. Borgonovo, L. Locatelli

This paper presents the ground settlement monitoring system used during the construction of two tunnels bored by two EPB TBMs, beneath the existing and active railway embankment in Bologna (Italy). The tunnels run close to large buildings and beneath bridges and other infrastructure. Data are collected from remote total stations and from electro levels installed directly on the railway tracks. The automated monitoring system acquires and analyses data then sounds an alarm in the event that there is a problem. Alarms are sent out in case of excessive tilt or settlement. Data is provided through a dedicated web application for multiple-party access, to gather, manage and store monitoring data.

Jan 1, 2007

The first mention of gold in Western Australia was in 1848 when some specimens of copper ore, which are believed to have come from the Murchison district, were sent to Adelaide for assay. Gold was present in these specimens, but no particular interest seemed to be attached to this fact as the search at that time was mainly concentrated on base metals and coal. Interest appeared to be shown in gold in 1852 when several parties moved out eastwards from York looking for goldbearing country. Though these parties inmany cases were very near to what is now known as the Yilgarn Goldfield, nothing was found.The next record of gold was reported in some specimens which were brought in from Cardup, some 25 miles from Fremantle. Though this area was investigated, it would appear that all the gold had been contained in the specimens and nothing further was found, though the report had been the cause of a small rush of people interested in gold.From time to time specimens had been brought in by various people from the district east of Northam, and in 1861 a reward emanating from private sources was offered for the finding of gold within a radius of 150 miles from Perth. The Government at this stage took an interest in exploration for gold and in the same year supplemented this privately offered reward on a £ for £ basis. The Government also, about this time, commissioned a practical miner, with prospecting experience in the Eastern States, to examine the country between Albany and Northam with a view to the possible existence of goldbearing veins in that area. His report, however, was entirely unfavourable and nothing further was done. In 1873 a quartz lode was discovered near Albany arid a company was formed to work...

Jan 1, 1956

By A. Fahimifar, H. Soroush

Abstract: In order to develop non-destructive methods in studying physical and mechanical properties of rock and replacing them with difficult and expensive static methods, several ultrasonic tests were carried out on cylindrical rock specimens in accordance with the ISRM suggested methods and velocity of P and S waves were determined. Also, density, porosity, water absorption, uniaxial compressive strength and indirect tensile strength were determined for each specimen in accordance with ISRM suggested methods. According to above tests static and dynamic elastic constants were calculated After statistical analysis of data obtained from tests, the relationships between velocity of elastic waves and physical or mechanical parameters were determined and some equations were obtained. Also similar analyses were performed on static and dynamic constants and some equations were extracted. Using these equations, the physical and mechanical parameters of rock and also static elastic constants can be estimated by conducting simple and quick tests (i.e. ultrasonic tests). Abriß: Um zu entwickeln, die zerstörungsfreien Methoden für Studieren die physischen und mechanischen Eigentümer von Steinen und auch ist für Ersetzen diese Methoden mit schwierigen teuren statischen Methoden, mehrere altrasonic Prüfungen auf zylindrischen Steinproben gemäß ISRM anregenden Methoden und den Geschwindigkeiten von S und P Wellen bestimmt worden sind durchgeführt worden. Außer der Dichtheit und der Porosität betonen Wasser Aufnahme und monoaxial Widerstand und dehnbaren indirekten Widerstand jeder Probe betreffend der erhaltenen Ergebnisse die atmosphärische Aufladung sind bestimmt worden und die dynamischen Faktoren der Steine sind kalkuliert worden. Nachdem statistische Analyse die Korrelation der Ergebnisse zwischen der Geschwindigkeit elastischer Wellen und mechanischer und physischer Eigentümer der Steine erhalten worden ist, und mehrere Verhältnisse sind vorgeschlagen worden. Eine ähnliche Analyse ist auf atmosphärischer Aufladung und dynamischen Faktoren durchgeführt worden und einige Verhältnisse sind erhalten worden. Mit Hilfe dieser Verhältnisse die physischen und mathematischen Eigentümer von Steinen und auch können die Statistik Faktoren durch einfachen und schnellen altrasonic Prüfungen erhalten werden. Resume: Puor le development des method non-destructive et evaluuation des propietes physical et mechanical des rock et superseding avec les methods dificzle et cher statique, c‘ est fait plusieur essayes ultrasonique sur les echantillons cylinrique et par a port le proposale TSRM et le vittesse des ondes P et S et densite et porosite et absorption des eaux le resistant de pression uniaxial et resistance de chaque echantillon est determinee. A la fin en base des resultat obtenue les constant statique et dynamique des roches sont calcule. Apres les analyses statistiquc sur les resultat obtenue du les essaybs, c‘ etait produit les relation entre les viptesse les ondes elastique et les proprietes physic et mechanicue des roches et c est propose quelque relations. Aussi le meme enterpretation sur les constant statique etdinamique. En possezon de ces relations, les spesificatio physique, aussi on peut trouver leur constant statique, avel les essayes sample et raptid a d ultrasonique.

Jan 1, 2003

By Lenny Winkel

With the aim to develop a solar-driven process for the extraction of copper from sulfide concentrates research on the decomposition of copper sulfides under inert atmospheres has been initiated. Thermogravimetric measurements on chalcocite,(Cu2S) revealed that copper is formed already at 1823 K. Chalcopyrite (CuFeS2) also disintegrates at this temperature, although at a lower rate. Copper and iron have been identified in the solid residue. The results confirm the feasibility of copper extraction by direct decomposition of sulfides under atmospheric pressure. The decomposition under inert atmosphere prevents generation of SO2, it also alters the behavior of volatile impurities during decomposition of copper sulfide concentrates. Chemical equilibrium calculations for chalcopyrite contaminated with enargite (Cu3AsS4) have shown that the absence of an oxidic slag allows for a complete evaporation of arsenic and subsequent separation from intermediate sulfides. The need to better assess the potential of direct sulfide decomposition has prompted the development of an experimental setup for studying the decomposition reactions. The experiment has been devised such that data on the decomposition kinetics and on impurity removal can be obtained at temperatures up to 2500 K.

Jan 1, 2003

By Gordon B. French, Donald E. Garrett

INTRODUCTION Crude oil reserves in the United States are still very large, even though for many years they have not been sufficient to supply our entire domestic requirements. They are continuously being depleted as oil is pumped from the ground, but new discoveries and improved secondary and tertiary recovery methods are helping to reduce the rate of depletion. It is thus a slowly diminishing resource, but even as it is being consumed, immense reserves of oil are left behind as the so called "un-recoverable" portion of petroleum formations. Most oil fields can only obtain a 15 to 40% recovery of the original reservoir, and it is widely quoted that there are still about 300 billion barrels of this un-recoverable oil still in place (Mauch, 1980, etc.). With the present comparatively high oil prices, and the possibility of even higher future prices and short supply, this oil becomes an interesting potential reserve. Mining the petroleum formation would be one means of recovering at least a portion of this oil. The concept of oil mining is neither new nor limited to conventional oil fields, since the procedure could be equally employed with the otherwise difficult to produce heavy oil deposits, and the solid or semi-solid tar sands and diatomaceous hydrocarbon formations. Estimates place the U.S. tar sand resource at about 30 billion barrels, and heavy oil at 5-10 billion barrels (Unitar, 1982). Figure 1 graphically summarizes the heavy oil reserves based upon formation depth and characteristics, while Figure 2 shows their location. It is apparent that the preponderance of reserves are in California and Texas, but that they also occur in many other states. The major companies engaged in oil recovery from the heavy

Jan 1, 1983

By Woodcock J. T, Jackson N

Wattle Gully Gold Mines N.L. of Chewton, Victoria, has decided to replace its present battery plant by a new mill to treat a free milling gold ore, after fine grinding, by concentrating coarse gold in a jig concentrate for amalgamation, and fine free gold and auriferous sulphides in a flotation concentrate for cyanidation. This paper outlines the economic justification and advantages of this step. In a review of the present position at the mine, a history of the company is followed by a description of the ore and its occurrence.Present treatment practice in two separate battery plants is described. Treatment tailings assay 1 dwt/ton gold and a substantial part of this gold is finer than 200 mesh.Experimental work showing how recovery may be improved is discussed and alternative methods of concentrating coarse gold mentioned. It is decided that the most suitable method for recovering gold from the ore is by jig concentration plus flotation.The merits of various flowsheets incorporating these techniques in the existing plant and in a new plant are assessed. It is concluded that there is no advantage in extending or converting the existing two battery plants, and it would be more economical and satisfactory to build a new plant.An economic study shows that for a capital expenditure of £120,000 a new plant could be erected to treat 70,000 tons p.a., working a 5-day week, and return an additional 14.2/- per ton, or £50,000 p.a., in revenue over the existing plant. It is estimated the plant cost can therefore be recouped out of savings inside three years. Probable ore reserves are sufficient to cover this period and additional ore will certainly be developed.INTRODUCTIQNSince 1934, Wattle Gully Gold Mines N.L. has been mining a lode gold ore at Chewton, near Castleniaine, and treating it by stamp milling and plate amalgamation, plus table concentration of auriferous sulphides. In 1954, following two years of unprofitable operation, a rehabilitation programme of all sections of the mine and plant was commenced. In the treatment section, two, major prospects for improvement...

Jan 1, 1959

By J. J. Gusek

There are hundreds of passive treatment systems accepting mining influenced water (MIW) throughout the world. Some systems do not perform to design expectations while others, including volunteer systems, have successfully operated relatively unattended for decades. The primary reasons for this situation include the common misconceptions that (1) a “cookbook” approach to design is valid for a wide array of MIW chemistries and site conditions, and (2) low maintenance means “no maintenance.” Passive treatment systems for MIW are typically manmade ecosystems that are designed to handle a specific range of metal loading conditions and MIW geochemistry. Thus, when design conditions are exceeded, the suite of microbial to macroscopic ecosystems may be slow to recover or mature. This should be no surprise to designers. But when a particular system fails, it may be inappropriately attributed to the technology, not the design. This paper presents a standard “phased” design protocol that appears to work and provides examples of sub-par performance of selected passive treatment systems.

Jan 1, 2002

By M I. Pownceby, N A. S Webster, R Pattel, N Ware

The decrease in quality of Australian iron ore, coupled with the demand for more efficient energy use, necessitates closer monitoring and optimisation of process conditions for iron ore sinter production. Sinter properties are correlated with the mineralogical content and traditionally, quality control has relied on methods such as Fe2+ determination, point counting via optical microscopy and automated electron beam techniques such as QEMSCAN; these can have a typical turnaround time of several days between sampling and reporting of results. As well, there is additional uncertainty around quantifying some of the complex mineralogical phases in sinter such as silico-ferrite of calcium and aluminium (SFCA) and SFCA-I, which are key phases influencing sinter quality. There is a clear need for the implementation of alternative analytical methodologies that offer a turnaround in hours or even minutes to provide information to accurately maintain production conditions.X-ray diffraction (XRD) is a technique widely used for the quantitative mineralogical phase analysis (QPA) of ores and processed materials in the iron ore industry. Partial least squares regression (PLSR) analysis methods have recently been suggested as an indicator of sinter Fe2+ content from powder XRD data without the need for rigorous and often time-consuming mineralogical analysis by the operator. In this study we provide results from the implementation of PLSR to predict the strength of iron ore sinter. Results are sourced from a well-constrained data set comprising strength properties (as quantified by a tumble index (TI)) from a series of compact laboratory test samples. Using this data set it was determined that PLSR has potential to be used as a method for calculation of sinter TI from powder XRD data and, therefore, process control.CITATION:Webster, N A S, Pownceby, M I, Ware, N and Pattel, R, 2017. Predicting iron ore sinter strength through X-ray diffraction analysis, in Proceedings Iron Ore 2017, pp 331–334 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By Katsuyoshi Kondoh

The utilization of silica particles originated in rice husks as reinforcements of magnesium composites was discussed. By using the solid state reaction of rice husk silica particles with magnesium powder, P/M magnesium based composites dispersed with the magnesium silicide (Mg2Si) and magnesium oxide (MgO) were fabricated. High-purity silica particles were originated from rice husks, one of the major agricultural wastes, via the citric acid leaching treatment and combustion in air. The effects of the silica particle characteristics such as size, crystalline and porous structures, on the reactivity of silica and magnesium to synthesize Mg2Si intermetallic were discussed. Amorphous silica was more useful for this reaction than crystalline one. The reactivity of rice husk silica was superior to that of the conventional mineral silica particles because of not only its amorphous structure but the larger specific surface area due to their pore structures. In the case of the green compact of the mixture of the rice husk silica and Mg powder, the silica particle size was not effective on the reactivity because the coarse particles were fractured into fine ones by cold compaction. The distribution of Mg2Si intermetallics of magnesium powder composites consolidated by SPS process was investigated by XRD and SEM-EDS analysis. Their mechanical and physical properties were also evaluated in detail.

Jan 1, 2009

Pyrite Bioleaching and Slag Neutralisation - Two Treatments in a Single Process for Recovering Valuable Metals from Both Materials Very often the production of copper sulfide concentrate yields pyrite concentrate as a by-product. This is the case at the Knre mine in northern Turkey. This kind of concentrate may contain low grades of valuable non-ferrous metals. Bioleaching of such pyrite concentrates is a processing technique to solubilise metals like copper, zinc or cobalt in a sulfuric acid pregnant solution. The pyrometallurgical processing of copper sulfide concentrate produces slag that still contains valuable metals in varying concentrations. Slag is used in many ways: as aggregates, ballast, pavement material, in cement production and glass making. Due to its relatively alkaline nature, it can also be used to neutralise acidic solutions. A preliminary study of the bioleaching of the pyrite concentrate (Co 0.28 per cent, Cu 0.56 per cent and sulfur as sulfide 42.6 per cent) produced at Knre has been undertaken with the assessment of the neutralisation of the acidic bioleach solution by using old slag (Co 0.29 per cent, Cu 1.70 per cent and sulfur as sulfide 0.89 per cent) stockpiled on the site. The main conclusions of the study were as follows: Knre pyrite was amenable to bioleaching at 40¦C. Cobalt solubilisation directly related to pyrite degradation reached a maximum yield above 90 per cent. Final copper recovery was limited to approximately 66 per cent not directly related to bacterial growth and pyrite oxidation. Slag could be used as a substitute for limestone as a neutralising agent in the bioleaching tanks. Cobalt and copper could be recovered from pyrite concentrate and slag simultaneously from both materials. A pre-feasibility study is underway to carry out a preliminary cost estimate of an installation for cobalt and copper production from these two materials processed in a single operation.

Sep 13, 2010

By J. T. Nel

Non-transfer-arc linear plasma systems are highly suited to manufacturing nanoparticles. In this paper, the manufacturing of such particles with specially designed plasma systems is discussed. In general, it entails the volatilization of a metal halide that is injected in the high-temperature region of a plasma flame, where it is reacted with a suitable reagent, for example O2, to produce nanooxide powders. Metal powders can also be introduced directly in the plasma. Due to the very short residence time of only milliseconds in the reaction zone, as well as the fact that the reaction takes place in the gas phase, combined with very rapid quenching in the order of 10 000°C.s-1, nanoparticles are produced. At Necsa the manufacturing of such particles has been demonstrated on various scales. A pilot plant for the production of nano-Al2O3, and two pilot plants, one using SiCl4 and the other one using SiF4 as feed material, were built to produce fumed, pyrogenic, nano-SiO2. The alumina plant had a production rate of 8?10 kg.h-1 and the silica plants had production rates of 2 and 10 kg.h-1 respectively. Perfectly spherical alumina particles with a particle size distribution of between 10 and 200 nm were produced on a continuous system. Particle size analysis for the silica by SEM measurements showed a d50 of 60 nm and a particle size distribution of 30?100 nm. The specific surface area was in the range of 170m2.g-1. Other samples of plasma produced nanoparticles such ZnO and B4C will also be presented.

Jan 1, 2010