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By T Baumgartl, D R. Mulligan, D Doley, A Schneider

In arid and semi-arid areas evapotranspiration (ET) cover systems are often used to mitigate contaminated seepage from hazardous mine waste into the adjacent environment. The theory of ET covers is based on the water balance equation with the aim of minimising seepage. While cover systems are commonly trialled, the influences of variability in climate and cover structure on water balance equation parameters are seldom investigated.Water balance equation parameters and their variability were analysed for two ET cover trials constructed from benign waste rock in semi-arid Australia. Seasonal and inter-annual variations in rainfall critically influence cover performance. For successful cover system operation, the average return periods for higher than average rainfall should be taken into account. In addition, failure of ET covers has a higher probability in areas with marked rainfall seasonality. Water holding capacity and plant available water content are low in covers constructed from waste rock. Changes in water holding capacity due to variation in particle size distribution are likely and critically influence cover performance. The application of topsoil can be beneficial for water ingress control through run-off, but a balance has to be struck between run-off, erosion and plant available water. Changes in vegetation composition only influence evapotranspiration water losses at plant coverage exceeding 50 per cent, which is unrealistic in semi-arid areas. This study showed that the capacity of ET cover systems to hold and dispose of received rainfall is often lower than assumed by industry practitioners. Furthermore, in order to improve reliability of long term cover performance, the variability of rainfall and water holding capacity of the cover has to be included in water balance models.CITATION:Schneider, A, Baumgartl, T, Doley, D and Mulligan, D R, 2012. Variability in parameters of the water balance equation and their influence on evapotranspiration cover performance, in Proceedings Life-of-Mine 2012 , pp 293-300 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By Akerkar D. D, Dey M. L, Mathur S. B, Chowdhury S. K R

The extraction of gold and silver from chalcopyrite concentrates has been investigated. In view of the recent interest in non-cyanide leachants for gold and silver, one such alternative reagent, namely thiourea, has been employed in the present work. Precious metal leaching was attempted from received copper concentrates as well as pre-oxidised concentrates. Pre-oxidation of the concentrates was carried out by three different methods, namely roasting, pressure oxidation and biological oxidation. After pre-oxidation and leaching of the base metals, the leach residues were subjected to further leaching for precious metal extraction. The results obtained on the extraction of gold and silver from received concentrates as well as pre-oxidised concentrates are presented and the effectiveness of the three pre-oxidation routes employed is compared.

Jan 1, 1992

By Barrie W. Sullivan

The New Celebration Gold Mine near Kalgoorlie in Western Australia was commissioned in late 1986 and the CIL treatment plant currently processes 1.7 million tonnes of gold ore annually. The 1988 geological resource was 13.2 million tonnes grading 2.37 g/t Au in several open pittable deposits with the bulk of gold mineralisation occurring as a stockwork in Archaean quartz feldspar porphyry intrusives along a major regional shear zone. Mine planning, scheduling and operating techniques have focused on minimising open pit dilution whilst maintaining production requirements. This paper describes the successful achievement of this aim in extremely variable ground conditions and orebody widths.

Jan 1, 1989

By Torben Ulisses da Silva Carvalho

A lixiviação é um processo hidrometalúrgico que consiste na separação entre o metal e a ganga através da dissolução em meio aquoso do mineral contendo os metais de interesse. O presente trabalho utilizou o minério de cobre oxidado da Mina do Sossego, sendo lixiviado em escala laboratorial com diferentes períodos de tempo, utilizando o ácido sulfúrico como agente lixiviante. A partir desses ensaios foram construídas curvas contendo os teores do minério de interesse contidos no licor e no rejeito, além do cálculo da recuperação metalúrgica. Os resultados foram encontrados utilizando a técnica de titulometria. Houve notada variação dos teores encontrados, os quais aumentavam proporcionalmente com os períodos de lixiviação. Esse comportamento mostra a necessidade de um maior número de etapas nos determinados períodos de tempo para uma recuperação metalúrgica adequada.

Aug 16, 2017

By R. Hogg

"The basic population balance models for agglomeration processes are reviewed and procedures are described for extending their applicability to systems with size-dependent rate constants and to the formation and growth of porous agglomerates from rigid, solid particles. Simplified procedures for the further extension of the models to include simultaneous agglomerate growth and breakage arc also described. IntroductionThe association of small particles into clusters or agglomerates is a significant factor in many facets of particle processing. Agglomeration processes are widely used to facilitate handling, storage and utilization of fine powders. Processes such as coagulation or flocculation are used to aid solid-fluid separation in dispersed particulate systems. Agglomeration also occurs as an accompaniment, often unwanted, to other particulate processing operations such as fine grinding, mixing and blending, transport and flow.Reliable agglomeration models are needed for improved understanding of the processes in general and of the complex role of numerous, interacting variables as well as for direct application to the design and control of industrial processes such as flocculation, granulation and pelletization. Ideally, the models should account for the primary forces responsible for agglomerate ·formation and growth, the effects of external forces on process dynamics, the development of agglomerate structure and its role in the process itself, and the effects of concurrent processes such as structure modification (e.g. compaction) and agglomerate breakage or degradation.In its most general form, the process of agglomeration involves taking discrete, independent particles, bringing them into contact with one another, promoting (or allowing) interparticle adhesion to occur and then causing structure rearrangement, usually under the action of external forces. The relative importance of these steps varies with the nature of the particulate system being agglomerated and with the kinds of agglomerates being produced. Coagulation or flocculation of particles dispersed in fluids is generally dominated by the contact and adhesion steps. In the granulation of powders, on the other hand, particles are already in contact so that structure rearrangement is the principal step."

Mar 1, 1992

In the five years since Great Central Mines Limited (GCM) commenced exploration in the Jundee and Bronzewing areas of Western Australia's Yandal greenstone belt, the Company has been transformed from a junior explorer into Australia's fourth largest gold producer with annual production of approximately 440 000 ounces and mineral resources of seven million ounces of gold.The growth in resources has been driven by a high quality geoscientific approach, supported by a substantial budget for drilling and strong management commitment. In 1997, the Company expects to spend US$30 million on exploration in the Yandal greenstone belt.

Jan 1, 1997

By Craig C. Hustwit

A pilot-scale treatment study was conducted on a copper-zinc bearing metal mine drainage using a pipeline treatment system called the In-Line System (ILS). The objective of this U.S. Bureau of Mines study was to determine whether the ILS could be extended from the treatment of coal mine drainages to the treatment of metal mine drainages. Hydrated lime (Ca(OH)2), quick lime (CaO), and caustic soda (NaOH) were used to neutralize the drainage. A novel reagent slurry of Ca(OH)2 and type C fly ash was also evaluated. Except for Ca(OH)2-fly ash slurry, treatment performance was evaluated for all reagents at pH values of 7,8,9, and 10. The Ca(OH)2-fly ash slurry was evaluated at a pH of 10. All reagents tested neutralized the metal mine drainage and substantially reduced the dissolved metal concentrations. It was concluded that the ILS could be useful in the treatment of metal mine drainages.

Jan 1, 2010

By D. Chakravarty, G. Samanta, B. Samanta

The present study highlights the planning and design aspects of a well-known openpit copper deposit in India. The mine has been operational since 1982 and presently reaches a depth of 168 m below the surface. The present planning effort has been given due consideration in view of the recent upsurge of copper prices in the global market. The prime focus of the study has been directed towards examining the possible extent of final pit beyond the current pit outline and generating an extraction sequence of future mining operations. To this end, an orebody model of the deposit has been developed and the optimized pit has been derived using L-G 3D algorithm. A sensitivity analysis has also been performed to scrutinize the possible effects of the changing economic scenarios on the ultimate pit configuration. It has been observed that with the current production rate, mine life can be extended another 40 years. With a five-year production plan, these materials can be extracted in eight push-back schemes. The extraction sequence of these push-backs has been outlined in this paper.

Jan 1, 2011

By William B. Senseman

FoR reasons well known to mining engineers, wet grinding is quite universal in plants having to do with the extraction of metallic values from crude ores. In the processing of the nonmetallic and industrial minerals, dry grinding is the more common method. The crude materials usually contain less moisture than is required for wet grinding and the products usually are marketed in dry form; most of them as powders. To grind wet, therefore, would entail the addition of water and an expense for drying the product, which is not justified. Furthermore, the material would be a dried cake that would still have to be pulverized or disintegrated before use. For producing fine products, air separators have largely replaced the earlier practice of sizing with screens and bolting reels. Mills in which the air-separating feature is an integral part of the design are now commonplace. Mill designs are many and air systems have developed along various lines, but for the purpose of this discussion, only the fundamental idea need be emphasized— the idea of using air for sizing and removing pulverized material from a grinding mill. About 20 years ago, when the use of mills equipped with air separation had become common practice, heated air or gas was introduced to such a system for the removal of moisture. The purpose of this discussion is to outline the developments and trends that have followed this experiment. It is an important development, for mills equipped with air separation are now universally used for pulverizing not only nonmetallic and industrial minerals, but a great variety of other materials. All such mills are essentially the same. Dried material is pulverized, removed by an air stream, trapped in a cyclone collector, and relatively clean air from the cyclone is returned through a fan to the mill. There is no theoretical need for a vent from the system. The practical need is to vent the air that leaks into the system; and, since the cyclone is not 100 per cent efficient as a dust collector, this vented air carries some dust with it. The initial attempt at drying was made on a system like that described, by the addition of a furnace. The minus pressure within the mill draws hot gas from the furnace. Infiltration air, along with the drying gases and evaporated moisture, is vented as before. The first application was made to a mill used for pulverizing coal. The coal contained very little moisture, so very little drying effect was needed for the success of this experiment. Actually, some calculated efficiencies of over 100 per cent were obtained before due allowance was made for the conversion of mill power into useful heat. When moisture is low, the heat obtained from the conversion of milt power is an appreciable part of that required. That drying can be effected in the short time interval available in a grinding mill of this type is better understood by visual-

Jan 1, 1948

By William B. Senseman

FoR reasons well known to mining engineers, wet grinding is quite universal in plants having to do with the extraction of metallic values from crude ores. In the processing of the nonmetallic and industrial minerals, dry grinding is the more common method. The crude materials usually contain less moisture than is required for wet grinding and the products usually are marketed in dry form; most of them as powders. To grind wet, therefore, would entail the addition of water and an expense for drying the product, which is not justified. Furthermore, the material would be a dried cake that would still have to be pulverized or disintegrated before use. For producing fine products, air separators have largely replaced the earlier practice of sizing with screens and bolting reels. Mills in which the air-separating feature is an integral part of the design are now commonplace. Mill designs are many and air systems have developed along various lines, but for the purpose of this discussion, only the fundamental idea need be emphasized— the idea of using air for sizing and removing pulverized material from a grinding mill. About 20 years ago, when the use of mills equipped with air separation had become common practice, heated air or gas was introduced to such a system for the removal of moisture. The purpose of this discussion is to outline the developments and trends that have followed this experiment. It is an important development, for mills equipped with air separation are now universally used for pulverizing not only nonmetallic and industrial minerals, but a great variety of other materials. All such mills are essentially the same. Dried material is pulverized, removed by an air stream, trapped in a cyclone collector, and relatively clean air from the cyclone is returned through a fan to the mill. There is no theoretical need for a vent from the system. The practical need is to vent the air that leaks into the system; and, since the cyclone is not 100 per cent efficient as a dust collector, this vented air carries some dust with it. The initial attempt at drying was made on a system like that described, by the addition of a furnace. The minus pressure within the mill draws hot gas from the furnace. Infiltration air, along with the drying gases and evaporated moisture, is vented as before. The first application was made to a mill used for pulverizing coal. The coal contained very little moisture, so very little drying effect was needed for the success of this experiment. Actually, some calculated efficiencies of over 100 per cent were obtained before due allowance was made for the conversion of mill power into useful heat. When moisture is low, the heat obtained from the conversion of milt power is an appreciable part of that required. That drying can be effected in the short time interval available in a grinding mill of this type is better understood by visual-

Jan 1, 1948

By G. R. Hopkins

The average quantity of heat needed to refine a barrel of crude oil in 1934 was 638,000 B.t.u., or about as much heat energy as contained in 5 gallons of fuel oil. Although the total heat utilized in 1934 was slightly above 1933, crude runs to stills increased 4 percent, hence the average requirement per barrel declined from 660,000 B.t.u. in 1933 to 638,000 B.t.u. in 1934 (see fig. 1). The average for 1934 constitutes a new record for firing efficiency, being just under the previous low of 1929. Heat consumption at refineries depends on many factors, of which the trends in yields of gasoline and lubricating oils are probably most important. The yield of gasoline is indicative of activity at cracking plants, which type of plant utilizes more than the average amount of heat per gallon of product. The yield of lubricating oils is indicative of the extent to which credo oil is refined; that is, it takes considerably more heat to refine a barrel of crude through lubricating oils than it does to separate only gasoline and kerosene. The yield of gasoline decreased from 43.7 percent in 1933 to 43.4 percent in 1934; on the other hand, the yield of gas oil and fuel oil increased. Although the yield of lubricating oils increased slightly in 1934 the theoretical increase in fuel requirements probably was offset by technical improvements, such as solvent refining.

Jan 1, 1935

By T. Holmes, S. Davison

"The Special Standard Surge bin at Agrium’s Vanscoy Potash Operations (VPO) has been plagued with flow problems and wear, and corrosion issues for it’s entire working life. Investigation showed that the carbon steel construction, bin geometry, and resultant funnel-flow pattern were directly responsible for production losses and disproportionate maintenance and capital costs. Potash enters this bin at between 140°C and 165°C, but the stagnant potash outside the active flow channel was much cooler, allowing moisture to migrate toward the outer regions, which caused corrosion of the walls and reduced live capacity as the potash in this area hardened and built up on the walls over time.A 2013 inspection revealed holes and paper-thin areas in the lower cylinder wall sections and in the conical hopper. The only thing preventing major leaks and even a potentially catastrophic failure was the buildup of stagnant hardened product on the cone walls. It was concluded that the cone had reached the end of its life and required replacement. VPO’s original plan was to replace the cone in kind and repair the cylinder as necessary; however, a failure-mode and bin-performance investigation combined with a lifecycle- cost analysis indicated it would be better to redesign the hopper.For success in retrofit projects, it is essential at the design stage to consider the bulk solid flow properties and the operating environment involved. Because education in this area is not offered at a university level, engineers often do not fully appreciate the effects of the flow properties of bulk solids on bulk material handling equipment.Jenike & Johanson conducted flow properties tests on samples of potash and using the data, redesigned the bin and the feeder. After the modifications, VPO’s surge bin provides safer, more reliable operation with a much longer predicted working life. Using this retrofit as an example, we aim to provide a general understanding of bulk solids flow theory and highlight the importance of customizing the design to the appropriate flow properties in the cost effectiveness, reliability, and safety of a bulk material handling system."

Jan 1, 2016

By Run-sheng xu, Hai-yang WANG, Di ZHAO, Teng-fei SONG, Jian-Liang Zhang

This paper was mainly focused on the different semi-cokes and charcoal which could be new fuels for blast furnace injection. Through the comparative study with bituminous coal and anthracite coal, the properties of semi-cokes and charcoal were presented in this research. 10 indexes of different fuels were obtained by different standard experiment, including proximate analysis, ultimate analysis, igniting point, explosivity, transportation characteristic, ash properties, grindability, calorific value, combustibility and reactivity with CO2. According to the data analysis, it provided a theoretical basis for rational utilization of various blast furnace fuels, and helped to broaden the scope of the blast furnace injection fuels. This research could contribute to energy conservation, emissions reduction, and sustainable development of iron and steel enterprises.

Jan 1, 2015

By Claassen J. O.

The Zinc Corporation of South Africa Ltd. (Zincor) operates an integrated roast ? leach ? electrowinning circuit. The efficient removal and control of iron forms an integral part of the process. Zincor developed its own iron removal process (Zincor Process), which was recently shown to be unique with some similarities to the para-goethite iron removal process. Newly developed operating parameters for iron removal are in the process of being implemented. These include a change in the pH-profile and operating temperature, the recycling of seed material and the utilisation of an alternative neutralising agent to aid iron removal. Some of these actions, together with the implementation of a pre-neutralisation step, new filtration equipment and control systems in Zincor?s Residue Treatment Plant have significantly reduced zinc losses associated with iron in calcine and the iron residue produced. This enabled Zincor to take a step closer to world-class zinc recovery levels of around 96% for a similar type of operation.

Jan 1, 2003

By H. J. Conolly

The area around Osisko lake, the Horne mine, and the town of Rouyn, in northwestern Quebec, presents a most interesting structural problem. The present discussion is confined to an area around Osisko lake, about six miles long and three miles wide, shown in Figure 1. The writers are particularly indebted to Mr. Thayer Lindsley, of Ventures Limited, who sponsored the investigation and gave permission to publish this paper. Mr. H. L. Roscoe and Mr. Oliver Hall, of Noranda Mines, Limited, gave every possible assistance; and the Noranda geologists, Mr. H. M. Butterfield, Dr. Peter Priee, and Dr. G. G. Suffel, contributed many data and ideas. It is a pleasure to acknowledge also the fuidance of Dr. W. F. James and Dr. B. S. Buffam and the full use made o their maps and criticism. Dr. M. E. Wilson and Dr. A. Lang, of the Geological Survey of Canada, kindly furnished data on the geology in neighbouring fields. Mr. E. Bailey assisted ably in the field, and Mr. H. F. King kindly reviewed the text. Memoir 166 of the Geological Survey of Canada, The Geology and Ore Deposits of the Roztyn-Harricanaw Region, Quebec, by Cooke, James, and Mawdsley, proved an invaluable source of information. STRATIGRAPHY The following stratigraphie sequence is based in part upon the interpretation of the structure as outlined in this paper:

Jan 1, 1936

By R. L. Grayson

Using powerful database management software, nested-field analysis and microanalysis of narratives have been made of West Virginia accident data, resulting in a new approach for targeting and prioritizing safety interventions by county, mine size, specific mine, job title, type injury, etc. and combinations of these parameters. The analyses have been useful in focusing training and discussion sessions on specific work problems, trends, conditions, and situations for targeted groups of miners. Application of the technique will be presented in this paper, along with comparisons of various mine performance measures.

Jan 1, 1997

By William A. Vogely, John E. Tilton

INTRODUCTION Mineral commodities are normally separated into three generic classes-metals, nonmetals, and energy minerals including oil and gas as well as the solid fuels. Metals, the focus of this chapter, encompass a large number of different substances. The U.S. Bureau of Mines, for in- stance, has commodity specialists following trends in over 40 metal products of importance to the country's economy and well being. Ranging from aluminum to zirconium, the metals display an incredible degree of diversity. Some such as lead are heavy, others such as magnesium are light. Some such as copper are good conductors of electricity. Others such as silicon are semiconductors. Mercury is found in liquid form, while some metals melt only when heated to extremely high temperatures. Iron and steel, aluminum, and copper are consumed in particularly large tonnages in a multitude of end uses, while many minor metals are needed in only small amounts in a few highly specialized applications. The use of some metals can be traced back into history for millennia, indeed back to the bronze and iron ages, while the commercial consumption of aluminum and other newer metals is less than a hundred years old. Some metals are extracted from large open pits, others are dug out of deep underground mines, and still others are processed from the sea. Mining and processing can be relatively uncomplicated and inexpensive, though in most instances highly sophisticated technology is necessary and the costs are high. Some metals are produced mainly as byproducts of other metals. Some are recovered in large quantities from the scrap of obsolete equipment and demolished buildings. Some are mined in only a few locations and traded worldwide, others are produced in many different countries. Some are sold by numerous firms at fluctuating prices determined on competitive commodity exchanges, others are produced by only a handful of firms and sold at stable producer-prices. This diversity makes the metals interesting, indeed fascinating, to study. Yet, it also poses problems, for each metal in its own way is unique. There is no general model or economic analysis applicable to all metals. Rather each must be considered individually, so that the analysis or model takes explicit account of its particular features. This means that a single chapter cannot begin to cover comprehensively the economics of all metals, and no attempt to do so is made here. Instead, we will concentrate on illustrating the usefulness of relatively simple economic principles, particularly those associated with supply and demand analysis, in understanding the behavior of metal markets. The next section begins by exploring the nature of metal demand. It is followed by an investigation of metal supply- from individual product production, from by- product and coproduct production, and from secondary production. The final section then illustrates the usefulness of the concepts introduced in earlier sections by using them to analyze

Jan 1, 1985

By Yan D. S

The removal of antimony from a refractory gold-bearing stibnite ore by roasting and selective chlorinating roasting was investigated. The influence of roasting temperature, roasting time, roasting atmosphere and type and amount of chlorinating agents on antimony removal were studied. The laboratory studies carried out included roasting tests of 4 g samples in a laboratory rotary kiln, followed by 400 g samples roasted in a fluidised bed. The test results revealed that antimony was efficiently removed by roasting at temperatures over 800¦C in a nitrogen atmosphere. The most efficient volatilisation of antimony was achieved with the addition of ferric chloride at temperatures between 350-600¦C.

Jan 1, 1995

By N. F. Manrique

El presente texto refiere el aporte de la química analítica como método de control en las operaciones de la industria minera. La química analítica trabaja con los métodos analíticos, los cuales están en constante actualización al tiempo que los análisis por instrumentación. En este sentido, se muestra que métodos analíticos clásicos como aquellos de reciente adaptación sirven para determinar el cobre, plomo, zinc, plata y oro, entre otros minerales, ais como se describe el rango, tiempo y costo para cada método utilizado.

Jul 20, 1961

By A. R. Rule

A flotation process was developed by the Bureau of Mines for separation of carbonate and phosphate minerals occurring in unaltered phosphate ores of the Phosphoria formation. The process involves depression of phosphate minerals with fluosilicic acid and flotation of carbonate minerals with fatty acid emulsions. In individual laboratory tests, selective removal of carbonates was achieved with phosphate recoveries ranging from 60 to 80 pct P205. In continuous-circuit testing, sizing and separate treatment of coarse and fine fractions was necessary to achieve 65-pct P205 recovery. Concentrate grade ranged from 26 to 33 pct P205. The flotation tailings containing primarily carbonate and phosphate minerals is a potential fertilizer material. When reacted with H3P04, concentrated superphosphate containing approximately 40 pct available P205 was obtained.

Jan 1, 1974