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By Daven N. Compton

The optical properties of Au nanoparticles have been known for some time, with both Au colloids and Au nanoparticles embedded in glasses having been extensively studied. In this study, Pt nanoparticles have been incorporated into Au colloids, and the linear and non-linear optical properties investigated. UV-VIS spectrophotometry, fluorescence spectroscopy and the z-scan method have been used to examine the effects of such additions.

Oct 1, 2003

By A. C. Wilson

In 1991, local prospector C. ?Mickey? Clement recovered at least three alluvial diamonds from the Michipicoten River. Two of these stones were sent to the Department of Mineralogy, Royal Ontario Museum, where they were identified as industrial grade diamonds with weights of 1.05 and 1.13 carats. Both stones were described as frosted and graphite-inclusion riddled. In 1995, prospector Sandor Surmacz and geologist Marcelle Hauseux discovered diamonds in bedrock approximately 20 km north of the Michipicoten River. An 18.1-kg bulk sample of a xenolith-rich lamprophyre, taken from an outcrop at the side of the Trans Canada Highway north of Wawa, yielded 1 macro diamond and 5 micro diamonds. All but one was gem quality (Sage 2000). Since then, more than 36 occurrences of diamonds in bedrock have been reported in an approximately 30 km2 area centred 20 km north of the town of Wawa. The occurrences are hosted within a sequence of unusual, Archean-aged, heterolithic breccias previously considered to have no economic significance. Ten kimberlite occurrences also have been confirmed in the Michipicoten greenstone belt in the last 5 years. Two of these kimberlites are diamondiferous. To date, expenditures on property acquisition and diamond exploration in the Wawa are estimated at $120 million (CAN). This paper summarizes the geological observations made on these occurrences and discusses including the relationship between the occurrences and the regional geology.

May 1, 2003

By J. A. King, D. A. Knight

"The Porgera orebody is located in mountainous terrain in Enga Province, Papua New Guinea. An underground mine has been developed which produces up to 2000 t/d of ore grading over 2 ozs Au/t. Some 79% of the gold in the ore is free, with the balance in a highly refractory form as sub-microscopic gold evenly disseminated within a pyrite matrix.This paper describes the metallurgical plant that uses flotation and cyanidation circuits to effectively recover the free gold in the ore feed, allowing for wide variation in the gold head grade. The refractory gold component in the ore is stored as leached pyrite flotation concentrate and this concentrate will be later treated by autoclaving techniques to recover the contained gold.The ProiectThe property is located in the Porgera Valley 600 Km North West of Port Moresby. The remote location is 2500 m above sea level. The mine area has 3600 mm of annual rainfall and a temperate climate with temperatures ranging from 10° c to 22° c throughout the year.Alluvial gold was reported in the Porgera area in 1938 and has been an important source of revenue for the area for many years. Intermittent exploration was carried out until the 1960 1 s when Placer (PNG) Pty. Ltd. with Mt. Isa Mines commenced an extensive exploration program. The property was brought to production in 1990 by the Porgera Joint Venture group consisting of Mount Isa Mines Ltd, Rennison Goldfield Consolidated Ltd. and Placer Dome Inc, each with a 30% ownership and the Government of Papua New Guinea with a 10% share. Placer Dome Inc. is the manager of the property with construction under the direction of the Placer Dome Technical Services group."

Jan 1, 1992

By Pengfu Tan

Converter slag chemistry control has played an important role in optimizing converter operations. A thermodynamic model of copper P-S converter has been developed to predict the behavior of magnetite in the converter slag. Predictions of bath temperature, slag and matte compositions, and magnetite content in the slag have been validated by industrial data. The effects of fluxing strategy, returns and skim charges, oxygen enrichment, and temperature on the magnetite formation in the slag have been predicted and discussed. Some improvements of the industrial operations have been presented.

Jan 1, 2005

By S. Slottee

The technology of making and using ?paste? from mine tailings is increasingly well known by the minerals industry. The primary applications are water recovery and ?stacking? of tailings with minimal use of dams and ponds. This paper highlights some applications, other than water recovery and stacking, that have come to the attention of a paste thickener equipment supplier. As generated by thickeners, paste (also called ?thickened tailings?) is a non-settling, relatively high concentration, suspension of solids that can be pumped. Paste deposits with an angle of repose, allowing minimal use of dams. High solids concentration allows more water recovery at the paste thickener than is achieved in conventional and high rate slurry tailings thickeners. This paper is based on paste as produced in a flow sheet that includes a thickener, underflow pumps that are typically centrifugal, transfer pumps that can be centrifugal or positive displacement, and a distribution system at the deposition site. Examples of paste applications other than water recovery or stacking include: ?mine? an existing tailings pond by removing slurry, recovering coal or iron ore values, and return the new tailings to the pond as a paste that does not res-suspend; use paste to seal an existing tailings pond from leaking to groundwater or to an underground mine; extend the life of an existing tailings pond by thickening the tailings to paste; move an existing dry tailings impoundment to a new location by slurrying, pumping, paste thickening, and redeposit; minimize the size of a filter by paste thickening the feed; operate a paste thickener and filter in parallel on a tailings stream with re-mixing to achieve a high solids concentration. The use of paste tailings technology has been expanding over the last 15 years. The applications, both implemented and under consideration, are increasingly diverse and include all minerals tailings. Tailings handling designers should always consider a paste option to the conventional slurry solution.

Jan 1, 2011

By Camier R. J, Perry G. J

Extensive deposits of brown coal exist in the Gippsland Basin, primarily in the Latrobe Valley. The total quantities of economically winnable coal in this region of Victoria and in other smaller fields are large enough to adequately assure Victoria's future electricity needs and to also provide large quantities for alternative applications, including liquefaction. As a result of the recent conflict in the Middle East attention has again been focussed on the production of synthetic fuels from coal. There have been many investigations over the years into the production of oil from Victorian brown coal. The purpose of this paper is to summarise the scope, objectives and major findings of these studies, with the emphasis on the direct hydrogenation route for converting brown coal to oil. The principal alternative processes are carboniastion and hydrotreatment of the product tar, or gasification and Fischer Tropsch synthesis of liquids from the product gas. The attractions of Victorian brown coal which have encouraged these studies include: ò the vast reserves of Victorian brown coal and the favourable conditions for low cost mining, ò the high quality of the coal (low ash, sulphur and nitrogen contents), ò the high reactivity of the coal giving high yields of product in hydrogenation to liquid fuels, ò the extensive data base available on the resource and its characteristics, and ò the availability of a skilled workforce and extensive infrastructure in the Latrobe Region to support a major resource development project. These advantages have been partially offset by: ò the high moisture content of the brown coal and the cost of drying, and ò the priority previously given to electricity generation in the allocation of the brown coal resource.

Jan 1, 1992

By M. P. Brungs, S. Haji Amini

Static dissolution of CaO into a CaO-SiO2-Al2O3slag and slags with additional fluxing agents (fluorspar, nepheline syenite and ilmenite) was studied. The slag was packed into dense CaO crucibles and heated to 1500ºC /1600ºC. After reaction, the crucible was air cooled and cross-sectioned. The development of the Ca2SiO4 phase and concentration profiles of various cations across the reaction zone were examined by Electron Probe Micro Analysis. At 1500ºC, a Ca2SiO4layer was found to form at the CaO/slag interface. No such layer was evident at 1600ºC. Ilmenite and nepheline syenite were found to be effective substitutes for fluorspar, increasing the rate of CaO dissolution.

Jan 1, 2004

By K. Oraee

Mining of copper ore and the related industries play an important role in Iran?s economy. Copper ore production in Iran accounts for 75% of the total production in the Middle East. All activities related to copper, that is, exploration, production, refinement etc are owned and managed by state owned companies. Decisions have been made to privatize all these activities. To assess the success of this privatization process, different components of the industry must be subject to economic analysis. In this paper, the cost estimation of all operations has been carried out. The total potential and attainable revenues have also been estimated using historical data available from the industry. Risk is a major factor in all mining activities and the copper industry of Iran has been subject to risk factors arising from many internal and external variables. These variables have been recognized and their effects evaluated. The effect of risk on the economic feasibility of the operations in the industry has also been analyzed.

Jan 1, 2011

Bioremediation of Acid Mine Water Using Fly Ash and Desulfotomaculum nigrificans One of the major concerns for the mining industry especially after the mine closure is the generation of acid mine drainage (AMD), and its discharge into the environment surrounding the abandoned mines, leading to serious environmental pollution. AMD is usually characterized by high concentration of dissolved metal ions, sulfate and low pH. The efficacy of fly ash was assessed for the removal of metal ions such as iron, zinc and copper as well as sulfate from synthetic acid mine water. Complete removal of ferric and ferrous, 80 per cent of Zn, 83 per cent of Cu and 62 per cent sulfate removal could be achieved, with a concomitant increase in the pH value from 2.3 to 7 using fly ash as an adsorbent under appropriate conditions. The free energy of adsorption of the metal ions onto fly ash was found to be negative, while the adsorption process was endothermic and adhered to the Lagergren pseudo-first order rate equation. Bioremediation studies using a typical sulfate reducing bacterium namely Desulfotomaculum nigrificans, after pre-treatment of the synthetic acid mine water with fly ash, cumulatively resulted in about 94 per cent zinc, 100 per cent copper and 90 per cent sulfate removal. The possible mechanisms of metal ion removal and sulfate reduction from acid mine water utilising Desulfotomaculum nigrificans are discussed.

Sep 13, 2010

By Stephen C. Tadolini, Gabriel S. Esterhuizen, Anthony T. Iannacchione

A Major Hazard Risk Assessment (MHRA) was developed in Australia after a series of mine disasters in the 1990’s. A MHRA is used to help prevent major hazards, i.e. fire, explosion, wind-blast, outbursts, spontaneous combustion, roof instability and chemical and hazardous substances, from injuring miners. A MHRA is a structured process that identifies the characteristics of major hazards, assesses and ranks the risk they present, and evaluates engineering and administrative controls to mitigate them. These controls typically consists of a broad spectrum of prevention, monitoring, first response, and emergency response techniques and helps to move an operation from a reactive to a proactive approach towards safety. This paper documents a MHRA performed at an underground mine where strata instabilities and fire hazards may threaten the condition of its escapeways. The objective of this MHRA is to 1) identify what hazards could affect the egress through the mine’s escapeways, 2) determine what unwanted events pose the greatest threat for the mine, and 3) recommend a plan to prevent or recover from the potential disruption of egress through the escapeway. The plan provides information on the key existing controls that should be monitored and audited, and makes recommendation of new potential controls to further reduce related risks. By documenting the use of MHRA to this specific ground control issue, this paper provides a framework for others to judge the merits of this approach and to help design and perform these activities.

By A B. Opperman

For many years explosives energy has been utilized in mining and construction as well as many other applications which are vital to our way of life. Many types of explosives have made their contribution as technology has moved forward. One of the best known was dynamite, which for many years was the mainstay of explosives users. Although dynamite had many advantages over its predecessors, it had the principal shortcomings of being somewhat hazardous to handle and was known as a headache producer.

Jan 1, 1975

By A. Himsley

"There is an ever-increasing demand these days for efficient methods of removing metals from solutions especially for selectively recovering a particular metal from a mixture of metals in solution.Up until the mid l 930's the only methods widely practiced for such separations involved precipitation techniques or electrolysis. Both these methods have limitations and indeed can only be used for certain metals.It is only within the last 40 years or so when synthetic ion exchange materials became available that chemists in industry and universities have been able to apply ion exchange techniques to a wide variety of separations that not only would be impossible by precipitation methods but which are now achieved with much greater efficiency.Ion Exchange TechniquesIon exchange is a unit process that can be applied using either liquid ion exchangers or solid resin particles. Liquid ion exchange - or solvent extraction as it is often referred to - is used in a number of special areas dictated mainly by the nature of the separation.On the other hand, ion exchange resins are much more widely used and consequently a great deal more is known about their application to a variety of metal separations.In both systems there is a loss of the ion exchange material which in the case of solvent extraction results in hydrocarbons going to waste. The ion exchange resin systems lose resin in the form of small particles, referred to as ""resin fines"", and these are insoluble.The loss of liquid ion exchanger is due to the fact that it is slightly soluble in water and consequently the loss is a function of the volume of liquid with which it comes into contact and is not related to the amount of metal processed."

Jan 1, 1975

By Stephen Hammond

?Our own prejudices form the greatest barrier to creating an inclusive working environment.? Have you witnessed? Racism or Negative Comments about an Aboriginal Person? ?You are free to compete with all the others?, and still justly believe that you have been completely fair.? Lyndon B. Johnson

May 1, 2008

In 1801, Hatchett discovered the oxide of a new element while he was examining a heavy black mineral from Haddam, America, which had been presented to the British Museum. He named the mineral Columbite and the metal Columbium. A year later a Swedish investigator, Eckeberg, while working with a new mineral resembling columbite-yttrotantalite discovered a new element, to which he gave the name of tantalum.In 1844, Rose announced the existence of two new elements in a sample of columbite from Bodenmais. One was similar to Eckeberg's tantalum and the other was called Niobium. Wollaston, in 1909, attempted to show experimentally that columbium and the tantalum were identical, but it was soon proved that they were two separate elements. Subsequently a number of investigatiors found other "new elements" in tantalum and columbium bearing ores, but these were shown to be mixtures of the twin metals.Since Hatchett's Columbium and Rose's Niobium are identical, it is more fitting to use the name assigned to this element by the earlier investigator. However, the term niobium is still retained in Germany and England.The separation of tantalum and columbium has been one of the major problems for analytical chemists since the discovery of the two elements and it is only in recent years that tantalum of a high degree of purity has been produced. High purity columbium metal is probably still to be obtained.Until 1903 tantalum was merely a laboratory curiosity, but about this time its use in incandescent electric light bulb filaments was discovered. Eight years later it was replaced by tungsten, which was better and cheaper. For a time the electrolytic valve action of tantalum was used in the charging of storage batteries, but the chief uses of the metals' to-day are for corrosion resistant apparatus, in vacuum tubes and as carbides in the manufacture of hard cutting and shaping tools.Most of the recent work on the metals has been done by C. W. Balke, in America. Tantalum has been studied more than columbium. OCCURRENCE OF TANTALUM AND COLUMBIUMI. NATURE OF ORESTantalum and columbium occur, nearly always together, as the oxides in combination with other metallic oxides. The only known exception to this is the reported occurrence of metallic tantalum with gold in the Ural Mountains. Unlike most other metals, no compounds with sulphur are known to occur in nature. Tantalum and columbium minerals occur usually...

Jan 1, 1943

By Matters C. W

THE following paper embodies the present practice and the results of past experience in the survey departments of two of the leading Broken Hill mines, the Central (Sulphide Corporation Ltd.) and the Broken Hill South S. M. Co. N. L.The authors intend to limit the scope of this paper to a consideration of office methods, as much has recently appeared in technical literature concerning field work, both surface and underground. Special reference may here be made to a valuable paper on 'Mine Surveying' by H W Gartrell, in Vol XIII of Transactions, in which the author gives considerable attention to field work. Moreover, much of the office work described in current literature is American, and sometimes not suited to local conditions, being ·often exceedingly elaborate and demanding a large staff of assistants. It is believed that the methods of recording information described in this paper are sufficiently simple and flexible to be adapted to most Australian mines. Brief acknowledgement must be made to the work done by Americans, who have raised mine surveying to the position of a separate profession, instead of being merely an unimportant branch of land surveying.

Jan 1, 1912

By E. C. Morton

The Western Australian School of Mines (WASM) has developed a facility for the static testing of large scale ground support elements. The samples are loaded using a mechanical screw feed jack. Instruments measure the displacement and the load being applied. Methods have been developed for testing of mesh, shotcrete and membranes. Mesh samples are restrained on all sides and loaded centrally. A new large scale punch test method has been developed to evaluate shotcrete and membranes. These products are sprayed on to a sandstone substrate containing a centrally located isolated disc. The sprayed product is loaded by displacing the disk. The different test methods are described in detail. The test program involved two types of mesh, several shotcrete mix designs with different curing times and one membrane product. The force-displacement responses are used to directly compare the products. The implications for implementation of the different ground support products are discussed.

May 1, 2009

By Gorzalczynski. Stan

The recent trend in underground mine developments is ?big is better?. This is most certainly evident in the mine shaft and the conveyances that operate within its compartments. Today, there are several new installations requiring mine cages that can transport up to 170 passengers. The technology in mine hoisting is advancing to address a combination of higher capacity requirements, deeper hoisting depths and faster winding rates, however, some areas of the hoist plant have not changed for the past fifty years. The most notable of these areas is the shaft compartment guide string and the conveyance mounted safety arrest mechanism. The technology in use today for the protection of passengers in a shaft conveyance from a hoist rope severance incident, remains conceptually unchanged from Elisha Otis? design of 1850. The actual retardation components, the safety dogs, have taken on several forms since Elisha?s invention with the last major design change occurring in the late 1940?s. The arrest of a free falling shaft conveyance requires that the shaft guides withstand the energy imparted on them by the safety dogs. There are some very real limitations presented by the use of wood for this application. The new hoisting era will most certainly continue to demand larger capacity equipment but also, an increased awareness toward safety.

May 1, 2002

By M. Hakala

A computer program was developed to simulate transient strains and stresses during an overcoring in the situ stress measurement. The solution is based on superpositioning of elastic stresses. The measured strains can be compared with the calculated ones to check if the measured transient behaviour is accordant with the interpreted in situ state of stress. If not, the in situ state of stress can be calculated based on any transient or final strain values. The transient stresses can be compared with the strength envelope of intact rock and thereby estimate the core damage potential. Technically, the developed code fulfilled all the objectives, and the numerical error was found to be less than 5%. The basic idea can be applied also for different overcoring probes with minor modifications and recalculation of stress tensors. The analysed case studies showed clearly the advance of having an objective and practical quality control method to study the reliability of the in situ stress measurement data. The study was set up and funded by the nuclear waste management companies Posiva Oy ( Finland ) and Svensk Kärnbränslehantering AB ( Sweden ). Un programme informatique a été développé pour simuler des tensions et des contraintes passagères pendant la mesure in situ de contrainte de surcarottage. La solution se fonde sur une superposition de contraintes élastiques. Les contraintes mesurées peuvent être comparées avec celles calculées pour vérifier si le comportement passager mesuré correspond à l'état de contrainte in situ interprété. Sinon, l'état de contrainte in situ peut être calculé à partir de n'importe quelle valeur de contrainte passagère ou finale. Les contraintes passagères peuvent être comparées avec l'enveloppe de force de roche intacte et ainsi il est possible d'évaluer le potentiel de dégâts au noyau. Techniquement le code développé a rempli tous les objectifs, et le taux d'erreur s'est révélé être inférieur à 5 %. L'idée de base peut être appliquée aussi pour différentes expériences de surcarottage avec des modifications mineures et le recalcul de tenseurs de contrainte. Les études de cas analysées ont montré clairement l'avantage d'avoir une méthode de contrôle de qualité objective et pratique pour étudier la fiabilité de données de mesure de contrainte in situ. L'étude a été fondée et financée par les sociétés de gestion de déchets nucléaires Posiva Oy (Finlande) et Svensk Kärnbränslehantering AB (Suède). Es wurde ein Computerprogramm entwickelt, um Transient-Beanspruchungen und Spannungen während eines Überentkernens in situ-Spannung-Messung zu simulieren. Die Lösung beruht auf Superpositionierung von elastischen Spannungen. Die gemessenen Beanspruchungen können mit den berechneten Daten verglichen werden, um nachzuprüfen, ob das abgemessene Transient-Verhalten mit dem interpretierten in situ-Zustand der Spannung übereinstimmt. Wenn nicht, kann der situ-Zustand der Spannung auf irgendwelchen Transient- oder endgültigen Beanspruchungswerten berechnet werden. Die Transiet-Spannungen können mit dem Stärke-Umschlag des intakten Felsens verglichen werden und dadurch ein Kernbeschädigungspotential kalkulieren. Technisch erkannte der entwickelte Code alle Ziele und hat gefunden, dass die numerische Fehler weniger als 5 % waren. Grundsätzlich können auch verschiedene Überentkernen-Untersuchungen mit kleineren Modifizierungen und Wiederberechnung des Spannung-Tensors angewandt werden. Die analysierten Fallstudien zeigten deutlich den Fortschritt, objektive und praktische Qualitätskontrollmethode zu haben, die Zuverlässigkeit in Situ-Spannung-Messung-Daten zu studieren. Die Studie wurde aufgestellt und durch Atommüll-Management-Firmen Posiva Oy (Finnland) und Svensk Kärnbränslehantering AB (Schweden) finanziert.

Jan 1, 2003

By R. Samuels, R. Klimpel

"IntroductionLaboratory and industrial grinding tests have shown that the process of size reduction of metal containing ores can be significantly influenced by chemicals added to the slurry being ground.,The terms grinding aid or grinding additive refer to a substance which, when mixed into the mill contents, causes an increase in the rate of size reduction. The increased rate can be used to grind a higher feed rate to the desired product size or it can be used to produce a finer product size at a fixed rate. Whether the use of a grinding aid is justified in any given situation depends on the cost of the substance versus the improvement of output or product quality obtained with its use.A wide variety of grinding additive mechanisms have been suggested in the general mining literature (1,2,3,4,5,6,7). The prevention of particle agglomeration, slurry cushioning of grinding media impact, grinding media coating, changing the strength of macro porous rocks, and chemical adsorption on flaw surfaces to change bonding forces and surface energy have all been suggested. More recently, some grinding additive work has been carried out (8,9,10,11) which suggests that the use of efficient chemicals to control the fluidity of dense slurries is a viable economic approach to achieve improved grinding rates. These increased grinding rates are achieved with no increase in power to the grinding mills and apparently with no increase in media consumption costs. Unlike much of the previous work with grinding additives, this recent work is accompanied by a rather complete engineering characterization and prediction of performance capability. The chemicals involved were chosen so as to efficiently control the viscosities of slurries under conditions of high shear yet not adversely affecting flotation, flocculation, and other downstream surface chemistry operations."

Jan 1, 1979

By E. C. Westman, F. J. Shreve

This paper presents the design and construction of a multi-channel geophone array that improves tomographic imaging capabilities in both surface and underground mines. Especially important in the design of the array is sensor placement. Three issues related to sensor placement are addressed in this paper: 1) sensor placement in long, horizontal boreholes, 2) development of simple, robust, MSHA-acceptable clamping unit, and 3) orientation of the geophones within the borehole. Improved imaging capabilities will produce energy, environmental, and economic benefits by increasing exploration accuracy and reducing operating costs.

Jan 1, 2002