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By N Javati, G D. Carman, D Kikiha, B Likia, K Dala, J McPhie, R Johnstone, D R. Cooke, J L. Blackwell

The 40 Moz Ladolam gold deposit on Lihir Island, Papua New Guinea is the worldÆs largest, low-sulfidation, epithermal gold deposit, in terms of contained gold. The deposit has average grades of 2.42 g/t Au (LGL Resources Reserves Update, 2008) and gold is hosted primarily in refractory pyrite. Lihir Island is part of the 150 km long, Tabar-Lihir-Tanga-Feni, alkalic, volcanic island chain located in the New Ireland basin. Five volcanic blocks comprise Lihir; Plio-Pliestocene Huniho, Kinami and Luise volcanic edifices are built on top of remnant Pleistocene Wurtol Wedge and Londolovit Block (Wallace et al, 1983). The Ladolam gold deposit is located in the central portion of the dissected Luise volcanic edifice and is composed of four main orebodies: 1. Minifie, 2. Lienetz, 3. Coastal, and 4. Kapit. An active geothermal system is overprinted on the ore deposit, localised along north-trending lineaments, and is expressed as hot mud pools and fumaroles. The focus of open pit mapping and drill core logging, as part of ongoing PhD research, has been in the Minifie and Lienetz orebodies. The deposit geology is grouped into four main phases: 1. volcano-sedimentary host rocks, 2. porphyry-style biotite alteration and related hydrothermal breccias and veins, 3. epithermal-style breccias and veins, and 4. modern geothermal alteration. Gold is associated with epithermal-style alteration and mineralisation. Ongoing observations of the Minifie and Lienetz orebodies are highlighting differences in the geology and paragenetic histories. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By R. Falcon, P. den Hoed, A. Luckos, R. Erasmus, V. du Cann, D. Comins

Carbon as a reductant, additive or filler is an essential element in the processing of metallic ores and the manufacture of iron and steel in the metallurgical industry. In most cases, the element carbon is derived from coal and its carbon derivatives. The properties of carbon required for the different processes in each metallurgical sector vary significantly and, for this reason, matching the correct carbon product for each specific process has become an important if not vital function in all sectors of this industry. This selection process, however, has become increasingly difficult. In many cases, the substitution of new products, despite being similar in all relevant chemical specification characteristics to previous products, has resulted in different performance properties relative to that expected. Under these circumstances, the prediction of performance of unknown carbon products has become fraught with difficulties unprecedented in the past. In order to initiate an investigation into addressing these issues, a test case was selected for indepth study the results of which are reported in this paper. The case concerned the use of a specific carbon feed in a conventional submerged arc furnace which gave rise to an unprecedented amount of unreacted or only partially consumed residue trapped in the frozen slag on the refractory walls of the furnace. During the course of these investigations, different advanced analytical technologies were employed including, inter alia, Raman spectroscopy, surface dimensional tests, organic petrology and various thermal reactivity factors. All results have been integrated into a multidisciplinary assessment presented in summary in this paper. Based on the above, and previous experience, the concept of an all-embracing 3-D coal-carbon ?framework? is briefly introduced. This approach has succeeded in obtaining greater depth of knowledge and a better understanding of the issues at stake with specific reference to the organic composition, structure, texture, internal surface area and consequent reactivity of the carbon materials concerned. In consequence, it would now appear that various properties of relevance to the metallurgical industry may be predicted with greater precision than has hitherto fore been possible.

Jan 1, 2004

By Maria K. Kojo

The interaction between various slags and a nickel concentrate containing pyrite, pentlandite, and violarite were investigated by submerging concentrate pellets in molten slags. The slags were contained in MgO-A12O3 spinel crucibles. The slag oxidizes the iron sulfides in the concentrate, resulting in a nickel matte. The amount of S02 gas formed during reaction was measured to determine the oxidation reactivity of the slags. The experimental variables included temperature, the ferric/ferrous ratio of slag, and other slag properties such as the FeO/SiO2 ratio and the MgO and NiO contents. The reactivity of the slag depended in a complex manner on its oxidizing power, viscosity, and interfacial tension. The slag composition for the greatest reactivity was determined to be Fe3+/Fe2+ = 0.3, Fe/SiO2 = 1.3, and % MgO = 2. This slag, however, caused substantial foaming. Increasing the MgO content to 10% or replacing it by 5% MgO + 8% NiO eliminated at a slight decrease in reactivity. The implications of the findings from this work in the bath smelting of nickel sulfide concentrates are discussed.

Jan 1, 1995

By Jialin Xu

Bed separations position, size, development characteristics and their influence factors have been analyzed in-depth by experimental and theoretical methods. The results show that the key strata determine the creation, development and space-time distribution of the overburden bed separations and fractures. Based on the dynamic growth principle during the two-stage development of bed separations, the theory of section-grouting for the overburden bed separation space and the O-ring theory for the pressure-relieved methane drainage are proposed. The technique has been applied in some coal mines in China to reduce surface subsidence and for methane drainage. Keywords: rock strata movements; key stratum; bed separation; bed separation grouting; pressure-relieved methane drainage

Jan 1, 2003

By Chuanshun Li, Haitao Zhang, Xuefa Shi, Quanshu Yan, Zhiwei Zhu

In Expeditions 22 and 26 of China Ocean Survey (COS), Chinese and Russian scientists have Carried out a lot of work to search for hydrothermal sulfide in Southern Mid-Atlantic ridge (SMAR) 19°S, but come back empty-handed at last. The sulfide formation is closely related with the water-rock reactions which are controlled by the heat source. Melt inclusions are considered to have a unique compositions in melt to reflect the deep magma processes. Fortunately, we have found a large number of plagioclase hosted melt inclusions in SMAR19°S MORB. We have done experiments by re-homogenization and re-crystallization of these melt inclusions. During the re-homogenization experiments, the forming and melting processes of the olivine crystal inside the melt inclusions indicate that the homogeneous temperature of melt inclusions is 1190-1200??. During the recrystallization experiments, the different mineral phase assemblages show H2O inside the melt inclusions has hardly ever been loss, in addition Cr element and H2O molecule in SMAR19°S magma are heterogeneity at the time of melt inclusions trapping, and then the re-crystallization experiments provide a method to prove the microheterogeneity of basaltic magma system. Combining with the bulk rock data, this study shows that the melt inclusions are formed at a low-temperature and high-pressure condition. Eventually, this paper speculates that a low temperature heat source generated by a lower mantle potential temperature or/and a thick lithosphere indicated by the melt inclusions that not experienced the H2O loss process are beneath the SMAR19°S. The low temperature heat source transmits its heat to lithosphere through the cooling thermal boundary layer (CTBL), and the thick lithosphere can sufficiently absorb and consume the heat. Under the interaction between the heat source and lithosphere, the residue heat at the infiltration depth of sea water might have been no ability to satisfy the water-rock reactions temperature, therefore, the water-rock reaction should hardly ever appear, so the theoretical reaction zone would not exist beneath the SMAR19°S. Eventually, the interaction between thick lithosphere and the low-temperature heat source should be the dominant factor that makes SMAR19°S area have no condition to form the seafloor sulfide. However, this paper is based on melt inclusions only, in fact, melt inclusions are potential to have melt compositions produced by mineral dissolution, reaction and assimilation, and the volumes of melt inclusions are exceedingly small compared to the overall size of the magmatic systems, therefore, the extrapolation across many orders of magnitude is implicit when applying petrologic information obtained from inclusions to entire magmatic systems. Therefore, there should have other more research to verify the reliability of this conclusion.

Jan 1, 2017

By Bruce R. Sutherland, Jim B. Ramsden, Gerry L. Bolton

Conductive metal powders are important building blocks for today's micro-electronic circuitry. Formulated into inks, they provide the interconnects needed to complete a complex integrated circuit and the means to enter the world of miniaturization. Traditionally, the inks have been based upon expensive metals such as silver, palladium, platinum and gold because of their excellent electrical conductivity and resistance to corrosion and oxidation. The use of a copper based ink, as an alternative to precious metal inks, recently has received considerable attention. Instability in the prices and limited supply of certain precious metal systems have driven up production costs, making the development of a lower cost copper system more attractive to manufacturers. However, lower production costs are on1 y real ized if performance and reliability can be maintained. While the development has been driven by cost, copper does offer some significant performance advantages over noble metal systems: conductivity as good as silver and 4W better than gold; leach resistance better than silver and equal to gold; stability at high frequencies better than gold or silver; strong film bonding characteristics; and compatibility with most solders. These benefits, however, do not come without cost. The inherently reactive nature of pure copper, while providing unique performance properties, makes it difficult to process. Unl i ke precious metals which can be fired in air, copper would oxidize and so requires special furnaces and atmospheres. Despite these difficulties, the transition from precious metal thick film systems to copper is gaining momentum. Manufacturers of high density, high performance circuitry are exploring the performance advantages of copper over gold and silver and the manufacturers of consumer products are considering the potential cost savings of copper over silver-palladium. Sherritt has developed a fine copper powder for this industry. Through association with the ink manufacturers, it has been found that performance properties of the ink vary with the physical and chemical characteristics of the powder. Production Process The production of very fine copper powders at Sherritt is based upon the disproportionation of cuprous ions as outlined in Equation [1] (1).

Jan 1, 1990

By E. W. Sawyer

Gelling-grade attapulgite and sepiolite clays are employed as thickening agents for the preparation of ionically contaminated drilling fluids where the use of fresh water clays are unfeasible or impossible. Attapulgite and sepiolite are nonswelling clays that can be dispersed and reflocculated by mechanical and chemical means to increase the viscosity of fresh water, salt containing waters, gypsum contaminated waters and fluids containing cement. Such gelled systems are quite stable in viscosity properties and can be further treated with other necessary additives such as thinners, water loss reducers, weighting agents, surfactants, etc. Many of the oil well drilling fluid practices have influenced such technologies as water well drilling, foundation drilling and waste disposal. The use of salt water gelling clays in these fields will be described and compared to oil well drilling.

Jan 1, 1986

By B. Comley, M. C. Harris

There is as yet no accepted method of predicting flotation frother performance in plant processes based on laboratory scale characterisation techniques. This paper investigates the use of dynamic surface tension, using the maximum bubble pressure method, as a means of evaluating frothers and frother mixtures. An adsorption model is presented, which has been used to quantify the role of frother type and concentration during frother bubble interaction, based on the correlation of model parameters to physical frother characteristics. This approach was found to provide useful insight with respect to blending and selection of flotation frothers to meet specified flotation performance criteria.

Jan 1, 2001

By J. E. Dutrizac

Mercury balances have been obtained for the flotation circuits at Pamour Porcupine Mines, Timmins, Ontario, and at Brunswick Mining and Smelting Corporation, Bathurst, New Brunswick. The mineral form of mercury in both deposits has been ascertained. At Pamour Porcupine, the mercury is approximately evenly divided among sphalerite, native silverelectrum and tetrahedrite-tennantite; at Brunswick Mining, this element is contained mostly in the sphalerite, although tetrahedrite (and possibly pyrite) also contains minor quantities.

Jan 1, 1979

By N. Agron-Olshina

The application of the QEM*SEM image acquisition and analysis system to the measurement of the mineral matter in coal and the materials in fly ash is described. A new sample mounting technique was developed using iodinated epoxy to provide a backscattered electron contrast between the coal, the mounting medium and the mineral matter. Several comprehensive and detailed species identification programs for silicate minerals and materials were developed to analyse the 1000 count x-ray spectra used for the measurements. Case studies are presented to demonstrate the capabilities of the new technique to distinguish different coals and fly ashes by their mineral and material composition rather than by conventional chemical analysis. Applications of the new technique are aimed at demonstrating that composition and size distributions obtained from OEM*SEM measurements can be used: 1. to characterize coal with respect to combustion problems in power stations, 2. to characterize coal for fine coal cleaning, 3. to characterize fly ashes in relation to problems such as erosion in combustion systems and the ease of precipitability in dust collection facilities, 4. to refine the classification systems used in marketing coal for pulverized fuel firing and fly ashes as a component of cement and building materials.

Jan 1, 1992

By Michael S. Moats, Scott C. Campin, J. Brent Hiskey

"Electrochemical techniques are a valuable means of analyzing the passivation of commercial copper anodes. Electrochemical impedance spectroscopy (EIS) provides information concerning transport and reaction phenomena occurring at an electrode surface. Commercial. copper anodes of varying compositions have been examined using EIS. Experiments were conducted in a flat cell with an electrolyte of 40 gil Cu2 + and 160 gil H2S04 maintained at 65 DC. Impedance spectra were obtained at the potentials characteristic of the open circuit voltage and passive region for each anode. The spectra of the passivating films exhibited a flattened resistive/capacitive loop at middle to high frequencies and an inductive loop at low frequencies. An equivalent· circuit utilizing an inductor-resistor series in parallel with the double layer capacitance and charge transfer resistance was adequate in modeling the impedance data. The influence of anodes impurities on the components of the equivalent circuit is discussed and correlated with a hi-layer passivation model.IntroductionPassivation of copper anodes during industrial electrorefining has received considerable attention in the past few decades. Great strides have been made in understanding the roles of anode impurities [1-25], electrolysis parameters [20,26], and electrolyte chemistries [20,26]. Even so, passivation still occurs even in the most modem of refineries. The exact cause of passivation is not fully understood. It is known that the anode surface becomes covered by a passivating film. This film has been proposed to be CuS04'&5H20, Cu20, or mixed oxides. The localized concentrations of Ft, Cu+, and Cu2+ ions determines which phase is more favorable. The presence of these ions is controlled by the reaction kinetics and diffusion of species through the slimes layer.Reaction kinetics between Cu, Cu +, and Cu2+ are based on the dissolution mechanism of copper. There exists four different models to describe the dissolution of pure copper. The classical model of Mattsson and Bockris [27] involves two single electron transfers with the cuprous-cupric reaction being the rate detennining step. More recently, Wong, Collier, and MacFarlane [28] used ac impedance to elucidate a more complex mechanism involving the affect of pH and anions. Their findings indicate that the formation of cuprous ions in solution, Cu(I)so~ is favored over Cu(1I) ions adsorbed to the electrode surface in the presence of sulfate and as pH increases from pH 1 to pH 5."

Jan 1, 1997

By M. Potesser

One of the main targets in the automotive mass industry and supplying industry is the weight reduction of the vehicle for decrease of the fuel consumption. For that reason combinations of different kinds of materials and connections of, for example, steel and aluminium are developed or are already successfully field-tested. A determining factor concerning the quality assessment of the welded joint during hybrid welding is the characterization of the intermetallic Fe-Al layer regarding strength, hardness, morphology and mainly the different phases in which Fe occurs together with the Aluminum (FeAl, Fe2Al5, FeAl3.). A combination of conventional light microscopy, SEM - EDX - analysis, the usage of an atomic force microscope including a Nanoindenter and theoretical thermodynamic calculations turned out to be highly effective. Based on the attained results, the constitution of the intermetallic FeAl layer, influenced by silicon, manganese and zinc, can be predicted.

Jan 1, 2006

By D. D. Liu

This paper proposes a charge induction dust measurement method based on detrended fluctuation analysis (DFA) for use in coal mine environments, based upon electrostatic interference, dust properties, wind speed, particle size, moisture content and other factors. In this methods, sequence x(t) is first obtained through a dust concentration sensing probe, and then the cumulative deviation y(t) is calculated, and y(t) is divided into same lengths. Secondly, a first-order linear fit is used for data of each interval, and mean-square deviation filtered DFA was calculated for each interval. Finally, the dust mass concentration of the corresponding time is obtain by supplemented calibration coefficient and fitted the data point which is the mean and square root for all lengths of interval. Simulation and verification experiments showed that the charge induction dust measurement method based on DFA can reduce coal mine electrostatic interference effects with high accuracy. The design has been successfully applied to select areas.

Aug 1, 2013

Dr Wark said: I have not come to Broken Hill to tell you how to conduct flotation operations; indeed, during my short stay here I have already learned much concerning the process, of the many difficulties which have been overcome, and of those still awaiting solution. My purpose tonight is rather different. All who have been concerned with the operation of the flotation process must have wondered, like myself, why the process is possible at all. In particular, why can minerals which are heavier than water be made to l10at to its surface; why do certain minerals float while others do not; and what are the functions of the added chemicals?I have been asked to describe tonight some of the ways which have been adopted in the Melbourne University laboratory in an endeavour to find answers to these. questions. Knowing that you are just as interested in them as we are and, furthermore, appreciating that were it not for the co-operation of the Broken Hill companies our researches would not have been possible, I regard it as a high privilege that I should have been invited to tell you of our work. Before doing so, I would like to tell you the reasons why the work was started and for whom it has been carried out. Soon after the flotation process had been successfully exploited on a commercial scale a number of investigators sought to determine the theoretical basis upon which it rests, and our knowledge of the function of the added chemicals has been considerably broadened by the published accounts of many workers, particularly in recent years of those working in American universities.The Australian metallurgist played, as you know, a part second to none in the early development of the process, and Australia's mining fields had already reaped such rich rewards from it that, late in 1929, it was felt by some of the leaders of the industry that we should take a larger part in the efforts being made to extend the knowledge of the principles upon which the process is based.Accordingly, several companies - the Broken Hill South, the North Broken Hill, The Zinc Corporation, the Electrolytic Zinc and the Mount Lyell Companies - established a laboratory in the chemistry department of the University of Melbourne for the purpose of investigating the principles underlying flotation.Subsequently another British company, the Burma Corporation Ltd, expressed a desire to co-operate.

Jan 1, 1994

By David E. Hyatt

The chemical attributes of cyanides have long been exploited in ore pro- cessing schemes for the recovery of copper, molybdenum, gold, silver, and other metal values. Blast furnacing operations are significant unintentional producers of cyanides which find their way into process waters. Many of the more than 20,000 electroplating facilities in the United States utilize cyanide plating baths and generate cyanide containing wastes. As social, political, and economic pressures for water quality attainment, maintenance, and preservation grow, the requirements for the development of treatment technology to control cyanide levels in wastewater become increasingly apparent. Just as the chemistry of the cyanide ion 1s an integral part of its industrial applicability, so must this chemistry be a fundamental part of any decomposition or removal technology used to control its level in effluent or recycled waters. The complexity of this chemistry is substantial and it cannot be considered in a superficial or cursory manner if control system design is to be both efficient and reliable.

Jan 1, 1975

By X. N. Hu, X. Shi, V. Vallyathan, N. S. Dalai

"Although silicosis has been studied extensively, the mechanism is still not fully under stood. Experiments do provide evidence that the actions of unique properties of silica surface on the cell membrane are the starting point of silicotic processes. This paper summarizes literature on chemical properties of silica surface, and the effect of particle size on silica toxicity. This paper also discusses the ways in which silica dusts are thought to interact with the cell membrane, with emphasis on freshness, hydrogen bonding, and free-radical interactions.INTRODUCTIONSilicosis is a debilitating pulmonary disease that afflicts persons (miners, foundry workers, ceramic workers, heavy construction workers, etc.) who chronically inhale silica-containing dusts (Schepers, 1960; Silicosis and Silicate Disease Committee, 1988). Since silica is second only to oxygen in weight percentage of the earth's crust (about 28%) and is found in an enormous diversity of minerals, it is natural that silicosis is one of the Major industrial health hazards all over the world. Although silicosis has been studied extensively, the mechanism by which the dusts exert their toxic actions on cells and the processes by which these-actions progress to fibrogenesis are still poorly understood. The biological characteristics of the dusts are largely unknown, although it is suggested that the dust size, shape, surface charge, roughness, surface chemical composition, trace metal content, and crystallinity; dose of silica in the ambient air of the workplace; duration of exposure; genetic variation in exposed sub¬jects; personal respiratory patterns; and presence of any coexisting dis¬ease (such as tuberculosis or rheumatoid arthritis) all influence the ex¬pression of silicosis (Koskinen et al., 1983; Noweir et al., 1980; Raask and Schilling, 1980; Reiser and Last, 1979; Thorne et al., 1985; Wolff et al., 1981). The actual biochemical mechanisms through which these factors operate are still unclear. However, the experiments do provide evidence that the actions of certain unique properties of silica surface on the cell membrane are the starting point of the silicotic process (Allison et al., 1966; Allison and Harrow, 1971; Bateman et al., 1982; Marks, 1957; Parazzi et al., 1968; Reiser and Last, 1979; Summerton et al., 1977). This article summarizes literature on chemical properties of silica dusts and how silica dusts are thought to interact with the cell membrane, with emphasis on hydrogen bonding and free-radical interactions."

Jan 1, 1989

By N. S. Dalal, X. N. Hu, X. Shi, V. Vallyathan

"Although silicosis has been studied extensively, the mechanism is still not fully understood. Experiments do provide evidence that the actions of unique properties of silica surface on the cell membrane are the starting point of silicotic processes. This paper summarizes literature on chemical properties of silica surface, and the effect of particle size on silica toxicity. This paper also discusses the ways in which silica dusts are thought to interact with the cell membrane, with emphasis on freshness, hydrogen bonding, and free-radical interactions.INTRODUCTIONSilicosis is a debilitating pulmonary disease that afflicts persons (miners, foundry workers, ceramic workers, heavy construction workers, etc.) who chronically inhale silica-containing dusts (Schepers, 1960; Silicosis and Silicate Disease Committee, 1988). Since silica is second only to oxygen in weight percentage of the earth's crust (about 28%) and is found in an enormous diversity of minerals, it is natural that silicosis is one of the major industrial health hazards all over the world. Although silicosis has. been studied extensively, the mechanism by which the dusts exert their toxic actions on cells and the processes by which these actions progress to fibrogenesis are still poorly understood. The biological characteristics of the dusts are largely unknown, although it is suggested that the dust size, shape, surface charge, roughness, surface chemical composition, trace metal content, and crystallinity; dose of silica in the ambient air of the workplace; duration of exposure; genetic variation in exposed subjects; personal respiratory patterns; and presence of any coexisting disease (such as tuberculosis or rheumatoid arthritis) all influence the expression of silicosis (Koskinen et al., 1983; Noweir et al., 1980; Raask and Schilling, 1980; Reiser and Last, 1979; Thorne et al., 1985; Wolff et al., 1981). The actual biochemical mechanisms through which these factors operate are still unclear. However, the experiments do provide evidence that the actions of certain unique properties of silica surface on the cell membrane are the starting point of the silicotic process (Allison et al., 1966; Allison and Harrow, 1971; Bateman et al., 1982; Marks, 1957; Parazzi et al., 1968; Reiser and Last, 1979; Summerton et al., 1977). This article summarizes literature on chemical properties of silica dusts and how silica dusts are thought to interact with the cell membrane, with emphasis on hydrogen bonding and free-radical interactions."

Jan 1, 1989

By M. Zaki El-Sabban

Tables of chemical thermodynamic properties for the ideal gas state from 0° to 1,000° K are reported for eight alkanethiols, three cycloalkanethiols and arylthiols, six thiaalkanes, two dithiaalkanes, three thiacycloalkanes, and three thiophenes. They are based on current physical and thermochemical constants and definitions, reliable vibrational assignments, and the latest insights into molecular structure and energetics.

Jan 1, 1970

By Donald W. Scott

Chemical thermodynamic properties for the ideal gas state from 0 to 1500 K are tabulated for all of the alkane hydrocarbons through C10. These properties are based on correlations of the extant data for the entropy, vapor heat capacity, and enthalpy of formation of individual alkanes and the equilibrium constants of alkane isomerization reactions.

Jan 1, 1974

The ready solubility of gold in dilute aqueous solutions of the cyanides of the alkalies or alkaline earths provides a convenient method for the separation of the precious metal -from the large surplus of associated materia1. The finely ground ore is pulped with a weak solution of cyanide, agitated to dissolve the gold, filtered and washed. The lowgrade filtrate is then clarified and the gold precipitated by some electronegative agent, the most usual being finely divided zinc or zinc dust. The slight precipitate is collectedon some form of filter coated with a filter aid, the filter cake being then known as "gold slime".A typical analysis of this slime is given in Table 1.

Jan 1, 1956