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By A. Fahr, T. Byczkowski, M. Genest, C. Mandache

"Layered aluminum structures assembled with rivets are often found in aircraft fuselage. These structures are exposed to various mechanical loads and a range of environmental conditions that contribute to their ""aging"". The rivet holes are the source of stress concentrations and the location of crack nucleation and growth. Detection and sizing of second and third layer cracks under fasteners represent a major challenge for non-destructive evaluation (NDE) technicians. Electromagnetic methods are currently the most feasible NDE techniques that are capable of successfully inspecting such structures. However, different probe lift-offs, due to protruding rivets and paint coatings, or interlayer separations, due to sealant or air gaps, pose difficulties in detecting and sizing cracks. In addition, the use of conventional eddy current technique is limited due to the inverse relationship between the probe spatial resolution and its field penetrability. In this paper, we present an alternative approach that overcomes the previously mentioned shortcomings by using pulsed eddy current excitation and magnetoresistive sensor pick-up. Various signal manipulations are employed for defect detection and quantification."

Jan 1, 2006

By M. E. Hurst

SINCE 1934 there has been a marked revival of interest in the Porcupine district, especially in the eastern portion of the area, where exploration on the property of Pamour Gold Mines has indicated the presence of extensive gold-bearing deposits. Owing to the prevalence of overburden and the limited amount of exploratory work that has been done, little information is available as yet concerning the distribution and structural relationships of the rocks in the area to the east of Porcupine lake. In order to throw some light on the structural conditions in this section, a brief discussion of the sequence and character of the formations in the better known, producing section of the camp has been included. It should be emphasized that this paper is a preliminary study and that, consequently, the conclusions expressed should not be regarded as final. The writer wishes to acknowledge his indebtedness to P. C. Benedict, whose study of the geological relationships on the Foley-O'Brien property has made possible a fuller understanding of the structure in the central portion of the area. The writer also wishes to express his appreciation of the information and facilities placed at his disposal by R. M. Macaulay and C. D. Stevenson, of Pamour Gold Mines, and by A. Bell, of Noranda Mines, Limited.

Jan 1, 1936

By L. T. Munn

"IT IS NOT necessary here to dwell on the fact that sulphur is currently in short supply. It may be well, however, to •point out that this •storage is not merely a temporary condition, but that, judging by trends in world consumption of sulphur, it may •be anticipated that requirements will double in the next ten years.Even with improved techniques for mining elemental sulphur in the United States and the new finds in Louisiana, there is much concern as to how these future sulphur requirements can be met. It appears necessary to .turn more and more to other sources than elemental sulphur for •additional production. The three major alternative sources were:(1) By-product sulphuric acid •from smelter gases.(2) Sulphur and sulphuric acid from iron sulphides.(3) Sulphur from hydrogen sulphide contained in natural gas. The Jumping Pound sulphur plant of the Shell Oil Company of Canada, Limited, is designed to produce sulphur by the •third of these methods.Jumping Pound is a natural gas field about 20 miles west of Calgary where Shell has a number of producing wells."

Jan 1, 1952

By G. A. Sutton

"At the San Manuel mine (Arizona, USA), in-situ copper leaching of a copper porphyry deposit was carried out from 1986 to 1999 during underground and open-pit mining. In 1993–1994, well¬field testing of the supergene zone, composed primarily of chrysocolla and copper-rich clay minerals, led to estimates that 52% of the acid-soluble copper (ASCu) could be recovered during in-situ leaching; however, the actual recovery from zone 6, which had the longest leach history, was approximately 42%. Comparing drillcore assay data from holes drilled before and after leaching also indicated an approximate recovery of 42%. The discrepancy between the predicted (52%) and actual (42%) recovery is probably related to several factors, including difficulty maintaining fluid saturation, channelling effects, and gypsum precipitation. ¦ KEYWORDS Copper oxides, in-situ leaching, Modelling, Porphyry, Solvent extraction and electrowinning (SXEW), Well-to-well RÉSUMÉ À la mine San Manuel (Arizona, États-Unis), on a procédé de 1986 à 1999 à la lixiviation in-situ de cuivre d’un gisement porphyre cuprifère pendant l’exploitation minière souterraine et à ciel ouvert. En 1993 et 1994, des essais effectués dans des champs de captage de la zone supergène, composée principalement de chrysocolle et de minéraux argileux cuprifères, ont abouti à des estimations selon lesquelles on peut récupérer 52 % de cuivre soluble dans l’acide (ASCu) pendant la lixiviation in-situ ; toutefois, la récupération réelle dans la zone 6, qui affiche l’histoire la plus ancienne en matière de lixiviation, était d’environ 42 %. La comparaison des données d’analyses de forage obtenues à partir de trous forés avant et après la lixiviation indiquait également une récupération approximative de 42 %. La différence entre la récupération prévue (52 %) et réelle (42 %) réside probablement dans plusieurs facteurs, notamment la difficulté à maintenir la saturation des fluides, les effets de canalisation et la précipitation du gypse. ¦ MOTS CLÉS d’un puits à l’autre, extraction par solvant et extraction électrolytique (SXEW), lixiviation in-situ, modélisation, oxydes de cuivre, porphyreINTRODUCTION in-situ copper leaching at the San Manuel mine, Arizona, USA (Figure 1), began in 1986. It was recognized that some of the copper oxide resource was not economically recoverable by conventional open-pit and heap leach methods using solvent extraction and electrowinning (SXEW) and a high stripping ratio would be required to access part of the resource. At the time, in-situ leaching was becoming popular in the uranium industry, but the approach was virtually unknown in the copper industry, especially at a large scale."

Jan 1, 2019

By Roger J. Goodman, Don Riva

"IntroductionCrows Nest Resources Limited (CNRL), a wholly-owned subsidiary of Shell Canada Resources Limited, is nearing completion of its first coal project, located in southeastern British Columbia. CNRL shipped over 700,000 tonnes of thermal coal to foreign markets in 1982. With the completion of the metallurgical coal plant in December, 1982, shipments of both thermal and metallurgical coal will increase substantially in 1983 and will approach the anticipated operating capacity of 3.0 million tonnes in 1985. The Line Creek Mine lies some 25 kilometres north of Sparwood in southeast British Columbia (Fig. 1). The open-pit mine is located on top of Line Creek Ridge, with coal being hauled 16 km to the thermal and metallurgical coal preparation plants, situated adjacent to the already existing Canadian Pacific Railway. Most of the coal is moved by 108 car unit trains by CP Rail to coal ports in Vancouver, where it is loaded onto vessels destined for overseas markets. Some smaller scale car load shipments are moved by rail to contiguous markets in the Pacific Northwest. History The southeastern British Columbia area, known as the East Kootenays, is steeped in a rich coal mining heritage, dating back to the latter part of the nineteenth century. Predecessors of Crows Nest Resources Limited were instrumental in developing the rich coal reserves in the area. In 1887, William Fernie, a pioneer-cum-prospector recognized the potential of coal deposits in the East Kootenays. Spurred by the relentless push west of the Canadian Pacific Railway through the Crows Nest Pass area, Fernie recognized that it was just a matter of time before the steam locomotives provided him with his required market. That time arrived in 1897 when Fernie helped to form the Crows Nest Pass Coal Company and coal mining commenced at Coal Creek, near his namesake town of Fernie. During its almost 70-year history, this company produced over 48 million tonnes of steam coal and 8 million tonnes of coking coal. In 1965, the Crows Nest Pass Coal Company was re-named Crows Nest Industries, to better reflect its expanded interests into forest products, and it is the latter company which Shell Canada Resources Limited acquired in 1978. The extensive coal resources of Shell, in both Alberta and British Columbia, were rationalized into one group with the birth of Crows Nest Resources Limited to manage and develop the coal holdings."

Jan 1, 1985

By L. Haavanlammi

The Outokumpu HydroCopper® process is a chloride based atmospheric leaching process alternative that can treat a variety of different concentrates. Chalcopyrite and other copper sulfides can effectively be leached under atmospheric pressure in strong, aggressive chloride solution using copper (II) ions as oxidant. Impurities are removed from the solution as carbonates and ion exchange. Copper is precipitated from the purified pregnant leach solution as copper (I) oxide, which is filtered and reduced by hydrogen gas to metallic copper powder, which is melted and cast into copper product. Sodium chloride solution from copper (I) oxide precipitation is decomposed in a chloralkali electrolyser, to products of which are circulated back to the process. The process has been designed for copper concentrates and is a fast and economical way to produce copper wire rod directly from concentrate. The process can efficiently handle impurities like arsenic and mercury, which can be harmful in the pyrometallurgical processes. The process has been tested in the laboratory and 1 ton/day demonstration plant scale and it has been proven to be commercially viable. The process has been designed to meet the strictest directives for emissions. Other environmental factors are carefully considered to obtain the highest possible eco-efficiency.

Jan 1, 2007

By L. Hacini

The start-up is the most critical phase of the cell life, as an uncontrolled start-up could lead to early infiltrations, instabilities, and in some cases to the cell death. Lots of efforts are put to increase the lifespan of cells, as it has a major impact on both the operating costs and the environmental footprint of the aluminum industry. Obviously, a true size test on a cell is a resources- and time-consuming approach that could be used only to validate mature concepts. Moreover, numerical modelling is a low-cost and versatile tool capable to test a wide range of potential ideas and concepts. In the present article, a thermal electrical mechanical slice model is presented. This model describes the preheating and bath periods of a P155 aluminum cell start-up, as used at the Grande Baie smelter. The impact of sodium diffusion and expansion is also included in the model. This model will be useful to study different problematical issues such as the global behaviour of lining materials, shell and cradle deformations during start-up and several start-up scenarios. Such a model will also be able to answer some interrogations regarding early infiltrations and their impact on the lifespan of the electrolysis cell.

Jan 1, 2011

By T. M. Waterland

A GREAT deal of work has been done at Britannia during the past three years in improving and standardizing rounds for development headings, and the results obtained have been very gratifying. The round which has recently been adopted as a standard for all drifts and cross-cuts has, in some instances, doubled the average length of break formerly obtained. It has also increased the footage of advance per labour shift and reduced explosives' consumption. At the present time, with a shortage of skilled labour, more control is necessar7 in directing the drilling of rounds. The use of a standard round has been o great assistance to the foremen and shiftbosses. NATURE OF GROUND Most of the ground encountered consists of a moderately silicified chlorite schist, known locally as G.M.S (green-mottled schist). It cannot be termed hard ground, because a three and one-half inch Leyner will drill at an average rate of twelve inches per minute. Due to the abrasive nature of the ground, the gauge of the steel wears rapidly and in most cases one set of steel is needed for each hole. The ground is not 'free breaking and holes must be spaced correctly to obtain a maximum break. DEVELOPMENT OF STANDARD ROUND FOR THREE-SHIFT OPERATION Late in 1940, a development programme was started involving 7,000 feet of drifting, 6 ft. By 7 1/2 ft. In cross-section, in two headings. Plans were drawn up to advance the headings on three shifts. Equipment used in the headings was as follows: D.A.35 Leyner?machines, Eimco Model 12B mucking machines, nine one-ton end-dump cars, one Mancha Little Trammer on the longest heading, 20-pound rail, 4-in. 15 compressed-air line, 15-in. Fan pipe connected to 5 h. P. Coppus fan. Diamond-drill cross-cuts, 16 feet in length, were cut every 250 feet. Switches were installed at these cross-cuts and they served as passing points for the cars. One siding seventy feet in length was cut in each heading at approximately the half-way point. The cycle of operations planned was to muck out, drill, and blast each shift. Previous performance in this type of ground indicated that a daily advance of 12 feet to 14 feet might be made. However, if a better type of round could be developed, an increased daily advance would be possible. A study of the time available for each operation in a net working shift of six and one-half hours indicated that the maximum depth of round that could be mucked, drilled, and blasted each shift would be six and one-half feet. When this maximum depth was decided upon, the next problem was to develop a satisfactory round. Due to ventilation difficulties and to the short net working shift, the whole round had to be blasted at one time. In other words, no blasting of the cut-holes could be done.

Jan 1, 1942

By M. Azzaz

In this paper, we report on new mechanical tests, at high temperatures, performed with a supposed better aluminium nitride (A1N) material, containing fewer oxygen. Our purpose was twofold: (i) check whether creep resistance is modified and hopefully enhanced and (ii) determine the elementary mechanisms controlling plastic deformation through transmission electron microscopy (TEM) observations of deformed samples up 10% strain in compression at elevated temperatures (1823-1923 K) under constant stress in the range 150¬250 MPa. Stationary rates are lower by an order magnitude than those previously measured in MN with higher oxygen content. All dislocations imaged by TEM look undissociated, which clearly relates the formerly observed wide dissociation to oxygen in excess.

Jan 1, 2004

By J. M. Carr

The history, geological setting and local geology of the Magnum vein system, 100 miles west of Fort Nelson in northeastern British Columbia, are described. The system comprises a number of quartz-ankerite veins, mineralized with chalcopyrite and lesser pyrite, occurring in a steep northeastly zone of deformation and subsequent dike intrusion within otherwise little-deformed Precambrian sedimentary rocks. In April of 1970, Churchill Copper Corporation began producing copper concentrates in a 750-tpd mill fed from the Magnum mine.

Jan 1, 1971

By L. Tejeda, J. R. Donald, R. Parra, J. Duran, P. H. Lauzon

"Crucible slag tests were employed to evaluate different refractory brick classes for the Cerro Matoso electric furnace. Comprehensive analysis was conducted to evaluate the crucible erosion and characterize any slag/refractory reaction products.The classes of refractories investigated were:•,tar-impregnated magnesia;•,rebonded fused grain magnesia-chrome;•,direct bonded magnesia-chrome;•,alumina-chrome;•,picrochromite; and•,magnesia-alumina (spinel).It was concluded that tar-impregnated MgO bricks were the most suitable for the slag chemistry and furnace environment according to corrosion and infiltration resistance. A picrochromite (MgCr2O4) brick performed exceptionally well with regards to erosion resistance, however, the slag infiltrated extensively through the brick pores. Alumina-chrome, direct bonded magnesia-chromite, and spinel (magnesia-alumina) bricks were evaluated as not suitable for use in the furnace."

Jan 1, 1999

By Yin Guangzhi, Song Zhenlong, Li Minghui, Li Wenpu, Deng Bozhi

"Darcy's law is widely used to describe the oil and gas flow characteristics in the multi-pore media reservoir. However, the low-velocity non-Darcy flow of oil and gas occurs in the multi-pore media reservoir under low permeability conditions. Meanwhile, the high-velocity non-Darcy flow of oil and gas occurs in the multi-pore media near the wellbore. The gas flow velocities in coal in different deformation stage under different gas pressure gradient were tested and the relationships between gas flow velocity and gas pressure gradient were discussed, which can help us to investigate the transformation conditions of gas linear flow and gas nonlinear flow in coal. The results showed that the gas flow in the coal under low effective stress environment can be described by Darcy's law. The low-velocity non-Darcy flow of gas gradually occurred and the start-up pressure gradient increased in the coal as the effective stress increased. The low-velocity non-Darcy flow of gas also occurred in the coal at the yield deformation stage, however, the start-up pressure gradient decreased as the effective stress increased in this stage. In post-peak stage, the highvelocity non-Darcy flow of gas occurred in the coal under low effective stress environment. The gas flow in the coal gradually returned to be Darcy flow as the effective stress increased. The mechanism of the phenomenon is discussed based on the experimental results. The research results can be used to guide well test analysis and prediction of oil-gas production. INTRODUCTIONThe oil and gas flow in original multi-pore media reservoir are usually regarded as steady and linear processes and can be described by Darcy’s law. However, the low-velocity non-Darcy flow of oil and gas occurs in the multi-pore media reservoir under low permeability conditions. Meanwhile, the highvelocity non-Darcy flow of oil and gas occurs in the multi-pore media near the wellbore or workface. The gas flow in the multi-pore media even may be unsteady under some conditions such as gas emission and outburst.The phenomenon of underground water low-velocity flow in clays was deviated from Darcy’s law was found in the end of the nineteenth century (King, 1898). The deviation from Darcy’s law was later reported and investigated more (Swartzendruber, 1962; Miller and Low, 1963). These researches revealed that the start-up pressure gradient exists under low permeability conditions. Klinkenberg (1941) proposed that the permeability constant as determined with gases is dependent upon the property of the gas, and is a linear function of the reciprocal mean pressure. This effect can be explained by taking into account the phenomena of slip, which are related closely to the mean free paths of the gas molecules."

Jan 1, 2015

By P. Personnet, D. Wheaton, E. Couzinie, V. Demetriou, Brooks. W., G. Girault, M. Meyer, L. Charbonnel

A common problem in Gas Treatment Centers (GTC) from primary aluminium smelters is the temperature of the gas to be treated : above a threshold, filtering media are irreversibly damaged. The traditional way of dealing with high gas temperature is to dilute with fresh air, which implies over sizing - and therefore higher cost for - the GTC in order to have the capacity to treat this dilution air without compromising on pot suction. A system was developed which decreases gas temperature without having to use dilution air. This system is based on water pulverization in gas collectors. The water vaporization leads to a temperature decrease of the gas. A pilot system was trialed in our R&D unit. Satisfactory results led to the development of an industrial system based on Envirocare equipment (partnership), which was trialed in our production plant in Tomago (NSW, Australia). This patented system was then generalized in this plant, which is now using it with success during austral summer.

Jan 1, 2006

By M. Potesser

Higher prices for natural gas or oil have motivated the copper industry to reexamine the modes of oxygen and oxy-fuel burner usage at operating plants. With rising energy costs and the growing importance of environmental protection, burner usage and burner operations have become the focus of several investigations and optimization efforts. One possible approach to lower energy usage is through combustion using tonnage oxygen. When such oxygen is used, the flame temperature increases and operational efficiency is improved. As well, with the correct technology, due to the presence of lower levels of harmful substances such as NOx in the off gas, there is improved environmental performance. As regards copper production, furnaces are employed for both concentrate smelting or for melting and casting operations. The use of tonnage oxygen in concentrate burners for smelting provides for a higher thermal efficiency. For furnaces employed for melting, air-operated burners may in fact have an initial advantage because a long radiant flame is typically generated, thus providing for a higher degree of heat transmission. This paper describes the new experimental burner chamber of Messer Austria GmbH which provides for testing of the combustion of natural gas with oxygen or oxygen-enriched air and the use of special water cooling ducts that simulates a metal charge during melting, The operational effectiveness of the burner is determined from temperature and off-gas analysis data. The paper also discusses future trends in burner technologies including a new patented burner. Cu2007 - Volume III (Book 2) The Carlos Diaz Symposium ou Pyrometallurgy Edited by A.E.M. Warner, C.J. Newman, A. Vahed, D.B. George, P.J. Mackey, A. Warczok Toronto, Canada,

Jan 1, 2007

By Perry L. Christian

"Mana/ta Coal Ltd. 's Costello Mine, located seven kilometres east of Estevan, Saskatchewan, has been operating at the present location since 1960. During the past twenty-three years, annual production of lignite coal has averaged 590 000 tonnes. The coal is used for power generation and for industrial and domestic use. Markets, operating techniques, facilities in place and reclamation are discussed. Introduction The Costello Mine (formerly the Klimax Mine) is located in southeastern Saskatchewan, approximately 210 kilometres southeast of Regina and 5 kilometres from the United States' border, as shown in Figure 1. The present mine, 7 kilometres east of the city of Estevan, has been operating since 1960. The history, however, of the Costello Mine and of the Estevan Coalfield dates from the initial settling of the area in the 1880s. Mining initially consisted of burrowing into the side of the Souris River Valley or other hillsides where the coal seam was exposed. Eventually, slopes were put down in the Estevan/Bienfait area and vigorous underground activity existed. In the late 1920s surface strip mining was introduced. The use of strip mining progressed to the point where it completely replaced underground mining in the 1950s and it is the only method in use today. During the past 23 years annual production has averaged 590 000 tonnes. The lowest production was in 1960 when the mine was starting up at 167 000 tonnes and the highest production was in 1977 when production was 1 509 000 tonnes. The Costello Mine controls approximately 11 400 hectares of mineral rights in the Estevan area. This is made up of 4 900 hectares of freehold coal and 6 500 hectares of leases. The area forms a large, irregular shaped configuration. Most holdings are contiguous and adjacent. The mine also owns some 8 400 hectares of surface rights. The lands under the Costello Mine's surface rights control, which are not being used in the mining operation, are leased to local farmers and ranchers. This ensures that the land is used to its full potential, both before and after mining."

Jan 1, 1985

By A. K. Debnath

The water resource is key to survival of the mankind and this resource is now becoming critical in many parts of globe including India. As per an assessment of Central Ground Water Board (CGWB) of India, a huge shortfall of about 58 billion m3 of water is anticipated by the year 2050. In order to counter this shortfall, there is thrust from Government of India to adopt water conservation measures. National Environment Policy, 2006 of Government of India also stresses upon the need to take up water conservation measures for water security of the country. The coal mines in India provide an excellent opportunity to take up water conservations measures therein. The mine water is not acidic unlike western countries and it conforms to the prescribed regulatory standards. This nature?s gift is utilized in Coal India Limited by allowing mine voids to get filled with mine water. The net recharge potential of the opencast mining area is found to be about 5% in comparison to 2% in non-mining area offering good prospects for ground water recharge. The seasonal rainwater is also diverted into mine voids left at the end of mining operations which act as huge reservoirs/ pit lakes for storage of the water. They also serve as surface water bodies for recharging of water table in the surrounding areas. The area and space left from where coal has been extracted completely in underground mines and will not be entered by any man or machinery after the extraction, called goaf, are also potential source of water conservation. These additional water resources created are being utilized for meeting the industrial, domestic, irrigation and other requirements of the projects and local communities eliminating the need to tap other fresh water resources including ground water. Presently, 75% of the water demand of the coal mining project is being met from the water stored in the mine pits. In future, CIL is likely to create about 3.3 billion m3 of water resource, on an average, in its opencast mines alone. In the mine closure plan of opencast mines, the last cut is proposed to be developed into water body for recharge of ground water and creating additional water resources. A clean potential source of potable water is thus developed after mine closure. This will ensure water security of the country.

Aug 1, 2013

By G. Velarde

Agglomeration has as main objective to form a uniform and highly permeable heap for leaching. An inaccurate dosage of moisture during agglomeration leads directly to poor agglomerate quality and segregation of particle sizes during stacking. This causes a heterogeneous distribution of the leach solution inside the heap which invisibly and practically permanently affects the recovery. Unfortunately, only when this becomes serious and the mineral contains an excess amount of fine particles and/or clays then the poor permeability of the pile becomes obvious. This paper is based on the experience of Minera Cerro Verde in the development and application of a quantitative method to control moisture during agglomeration. As the amount of fine particles/clays varies, the quantity of moisture has to be altered in real time. The measurement of agglomerate electrical conductivity is used for it. This concept is based on the sharp change seen in conductivity when the mineral passes its absorption limit. A liquid conductive film then begins to form over the surface of the particles, which leads to the formation of agglomerates through liquid bridges, which are also electrical bridges. Moisture is adjusted to reproduce a value of conductivity established previously and is the guiding parameter. Moreover, moisture amount added to reach this conductivity parameter provides information about the fines/clays relative content for best leaching management.

Jan 1, 2004

By M. C. Harris

"Excess Gibbs energy is a thermodynamic parameter which quantifies the difference between the value of the Gibbs energy for a real mixture and that for an ideal mixture. More specifically the partial molar excess Gibbs energy of a species (i) in a mixture is indicated by the change in the overall excess Gibbs energy of the solution as the number of moles of species (i) changes while keeping temperature, pressure and the number of moles of all other species in the solution constant. Generally it is obtained from the activity coefficient which in turn can be obtained for a species in a mixture using a variety of models. The most widely used method is to use UNIFAC. Flotation is probably the most important process in the concentration of minerals and requires the use of reagents such as collectors and frothers. There is abundant experimental data which illustrates that collectors of different alkyl chain lengths will change the contact angle and that frothers of different structures and molecular weights will result in changes in key flotation properties such as froth behavior, surface tension and critical coalescence concentration. In this paper it is shown that there is a strong linear relationship between measured parameters such as froth volume/height, surface tension, critical coalescence concentration and contact angle and the partial molar excess Gibbs energy of the molecules used. Proposals are made to explain these correlations.INTRODUCTIONAs is well known froth flotation is arguably the most widely used process in the separation of minerals. In broad terms the process relies on the use of reagents known as collectors to adsorb onto a mineral surface and thus render the mineral particle hydrophobic. Alkyl thiolates are very commonly used for this purpose. The hydrophobicity is induced as a result of the alkyl group’s molecular structural properties which results in it forming a non-ideal mixture with the process water. Surfactants (or frothers) are typically alcohols and are known to lower the surface tension of the system and also inhibit bubble coalescence and reduce bubble size. Since alcohols are polar they will also form a non-ideal mixture with water. The hydrophobic mineral attaches to the bubble and rises to the froth phase where the valuable mineral is recovered as a concentrate. Frothers have often been characterized using the so-called HLB (hydrophobic-lipophilic balance) number but recently it was shown that the use of activity coefficients (?) or excess Gibbs energy (G ex ), which is calculated using equation (1) is a much more appropriate way to describe the behavior of these reagents in non-ideal mixtures with water (Corin and O’Connor, 2014)."

Jan 1, 2016

By Edward Rybinski

Compañía Minera Antamina is a polymetallic mining complex that produces copper and zinc concentrates as primary products and molybdenum and lead/bismuth/silver concentrates as by-products. In 2007, Metso Process Technology and Innovation (PTI) was contracted to increase SAG mill throughput by integrating and optimising blast fragmentation, crushing and grinding for the harder M4/M4A (CuZn) ores. Following the implementation of recommendations provided by Metso PTI, the SAG mill throughput increased from 2750tph to reach an average of 3600tph for the remainder of 2007. Due to continued application of mine to mill integration and optimisation philosophy, by 2010, the concentrator consistently exceeded the target of 4400tph while processing harder CuZn ores.

Jan 1, 2012

By H. Vendette, N. R. Dando, A. Moras

The thorough analysis of results obtained from different testing campaigns performed on an alumina dry-scrubber pilot installation treating aluminum potline offgases, suggests a clear relationship between the emissions of gaseous fluoride and the fluoride saturation level of the alumina. The integration of this relationship into the development of a new generation of alumina dry scrubber represents an intriguing challenge regarding the design of more efficient air pollution control equipment. An innovative scheme challenging conventional industry practices was proposed. From theoretical simulations, the reduction in fluoride emissions can potentially be reduced by as much as 50% in the summer season. To validate this innovative approach, Solios in partnership with Alcoa Primary Metals, modified one of the Aluminerie de Deschambault's systems by adding new temporary equipment on the operating units and subjecting it to several test campaigns. This article presents the first results obtained in testing this new and innovative approach on alumina dry scrubbers used to capture fluoride emissions coming from aluminum electrolysis potlines.

Jan 1, 2006