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Despite the claims of energy efficiency and the considerable development that has gone into dramatically extending rolls’ life and facilitating rolls’ change-out, in the six years since the last SAG conference, only a few HPGR operations have entered the realm of mineral processing. Risk barriers to the take-up of new equipment or processes are: a massive increase in materials handling issues as well as in the number of pieces of equipment required, low total circuit potential energy savings, and similar or higher capital costs. An alternative route is to make use of the complementary strengths of the HPGR and SAG in hybrid circuits. Minimising materials handling issues, providing an ideal balanced feed to the AG or SAG mill, and improving controllability through shifting grinding load as the RoM feed changes, are all potential major advantages to this approach. Conceptual circuit layouts, based on real measured ore and equipment data, are presented here to illustrate the potential production upside, the reduction in operating costs and the reduction in the physical and energy footprints.

Jan 1, 2012

In recent years, China and India have emerged as major players in the copper sector. Over the last decade, around 50% of additional global refined copper usage growth can be attributed to them. The paper provides an overview of the current and future copper supply and demand situation in both countries. Results from two market studies commissioned by the International Copper Study Group (ICSG) are complemented with recent copper statistics on North-East and South-East Asia, as well as further sectoral analysis. Developments and trends in copper mining and metal production, semis production, and major end use areas are highlighted. While providing insights into sectoral patterns and growth trends, the paper provides the basis for comparing structure and output of the copper sectors in some of the major copper-using countries in Asia. Afterwards, the current copper reservoir in use associated with infrastructure, buildings, industrial equipment, transportation systems and households is assessed using the ICSG Copper Flow Model. Finally, the identified copper flows are analyzed regarding the potential impact on the future world supply and demand situation.

Jan 1, 2007

By V. Ramachandran

The successful advent of solvent extraction (SX) reagents for copper recovery and improvements in electrowinning of copper to produce LME grade A copper cathode have paved the way for the hydrometallurgical treatment of copper oxide and low grade sulfide ores. This has resulted in about 25-30% of the world's copper being produced today by the Leach-SX-EW process. The obvious next step was to develop processes for the hydrometallurgical treatment of copper sulfide concentrates, as an alternative to a typical smelter-refinery complex. The current paper updates the processes that have been developed to date with emphasis on processes that are being commercialized or that are seriously under consideration for commercialization. Most of the discussions relate to the hydrometallurgy of chalcopyrite concentrates, which account for about 70% of the world's known copper reserves. In summary, in the last thirty years, the hydrometallurgical treatment of copper sulfide concentrates has attained full maturity and will be a serious option to contend with while evaluating any future new copper plant.

Jan 1, 2007

By Mary Jean Buchanan

The last twenty years have seen the advent of environmental concerns and sustainable development, and the industry has witnessed the rise of Environmental Management Systems and their registration through several international standardization systems such as EMAS and ISO 14001. Beyond EMS and ISO 14001, which new goal the mining industry should aim at. Life-cycle assessment (LCA), another tool from the Environmental Management System series, is also on the rise and currently the object of an international standard (ISO 14040:1997). Through LCA, it is possible to assess the environmental aspects and potential impacts associated with products and services, taking into account all the activities required for its fabrication, its use, its transportation and its disposal. How could LCA be applied to the mining industry ? Is the international market pressurizing on mining companies to supply an ?environmental ore?? What about the automobile industry and its use of LCA ? Will it influence the ferrous and non-ferrous metal industry, suppliers of raw materials ? This paper presents a review of possible applications of LCA for the mining industry as well as world trends.

May 1, 2001

By C. Tasker

Introduction In the Early part of 1930 the Ontario Research Foundation was asked by the Minister of Mines, the Hon. Charles McCrea, K.C., M.P.P., to undertake a technical and economic investigation of the Northern Ontario lignite deposit. This investigation has been under way since June, 1930, and has necessitated considerable work at the deposit, in the laboratories of the Foundation, and at test plants in Europe. All the work has been carried out in active co-operation with the Provincial Department of Mines, the Deputy Minister, Mr. T. F. Sutherland, and several of his technical colleagues being associated with members of the staff of the Foundation on the Advisory Committee, which has met at frequent intervals to co-ordinate and direct the various lines of research. An interim report was made to the Minister of Mines by the Director of the Foundation, Dr. H. B. Speakman, at the end of December, 1932, and is at present under consideration by the Minister. This report deals with the extent and character of the deposit, the methods and costs of mining, and the methods and costs of processing raw lignite, the characteristics of certain lignite products, and the technology and economics of present fuel utilization by railways, industry, and domestic users in northern Ontario. It is not the purpose of the author to discuss in this paper either the geology of the deposit or the economics of the mining, processing, and utilization of lignite, but rather to deal briefly with some of the technical problems investigated by the Foundation during the study of the characteristics and methods of utilization of Northern Ontario lignite. Some mention, however, of the work carried out to define the extent of the deposit is a prerequisite to any discussion of the nature of the lignite.

Jan 1, 1933

By W. H. MacLean, S. Liaghat

The Key Tuffite is a thick (0.3 m to 6 m) and laterally extensive (-10 km) cherty, sulfide-bearing tuff unit in Archean greenstones in the Matagami mining district in northwestern Quebec. It lies at the contact of the Watson Lake Group and overlying Wabassee Group volcanic rocks, and is host to major Zn-Cu volcanogenic massive sulfide deposits. The tuff component is highly altered and its volcanic precursors are not identifiable by petrographic means. The tuff is mixed with a volcanic exhalative component comprising chert, carbonate and sulfides (pyrite, pyrrhotite, and minor sphalerite and chalcopyrite). The normative mineral composition of the Key Tuffite is 33% quartz, 28% sulfides, 16% sericite, 8070 carbonate, 6% chlorite and 9% other minerals. In the vicinity of the Bell Allard and Orchan mines, the precursor tuff components are identified using immobile major and trace elements, as Watson Lake tholeiitic rhyolite (Zr/Y = 1.5 to 3.5, LaN/ybN = 1.7 to 2.8, SiO2 = 72.5 ± 1.2 wt %, and Wabassee calc-alkaline andesite (Zr/Y = 9, LaN/YbN= 4 to 8, SiO2 = 56% to 65%). Immobile element computation techniques were used to calculate mass additions and losses in the conversion of the tuff to the Key Tuffite. Average net amounts of FeP3 (27% total iron), Si02 (14%), Cao (8%), S and K2 (+ 2%), were added, Nap was removed (-2.8%), and MgO was over-all unchanged. Total net mass change was +63%, which comprises mainly exhalative additions, but also includes changes owing to hydrothermal alteration of the tuff component.

Jan 1, 1992

By James W. Cameron

DESPITE the fact that, after oxygen and silicon, aluminum is the most abundant and widely distributed element in the earth's crust, it is, commercially, a modern metal. Attempts were made by Sir Humphrey Davy and other chemists to decompose alumina, the oxide, into its elements, but with unsatisfactory results, and it was not until 1827 that Wohler succeeded for the first time in isolating the metal in pure form. Some thirty years later, commercial production of aluminum was started in a plant near Alais, France, using a process developed by Deville which was a modification of that of Wohler. It was not, however, until around 1886 that possibilities of low-cost production were realized. Hall and Heroult discovered, independently, the now famous process for extraction of aluminum by the electrolysis of alumina (Al,O,) dissolved in fused cryolite. This discovery, with its subsequent effect in reducing the price of the metal, was perhaps the greatest single factor contributing to the remarkable growth of the aluminum industry. But only in the years following the Great War did aluminum begin to attain equal importance in many fields with other non-ferrous metals. Numerous factors, political and economic, in the past decade have had a profound effect on the industrial history of the metal. At present, systematic substitution of aluminum for other base-metals is proceeding at a rapid rate in such countries as Germany and Italy with a view towards 'economic self-sufficiency'. Quite naturally, ?the economic depression started extensive research and experiment in various industries in an attempt to improve efficiencies and lower costs. Partial answers have been found in the extended use of aluminum and its alloys. Even against the background of tremendous technological advance that has marked the past fifty years, the rise of the aluminum industry must necessarily stand out conspicuously.

Jan 1, 1939

By Helen Shang, Jianjun He

In nickel and copper production, sulfur dioxide (SO2) is generated during mineral smelting. Emission of sulfur dioxide into the atmosphere causes serious health and environment issues. Sulfuric acid plants, which convert the harmful SO2 gas to commercially useful sulfuric acid product, ensures safe and environmentally sound smelter operations. The sulfuric acid plant is mainly composed of a SO2 to SO3 converter, a series of heat exchangers and SO3 absorption towers. The SO2 converter is crucial for minimizing SO2 emission in a smelter. In this paper, steady state and dynamic modelling are carried out for the converter using mole and energy conservations. Simulations are performed to investigate the effect of feed conditions on SO2 conversion. The developed model represents an important component for modelling the acid plant in a smelter and is expected to provide a fundamental tool for the future optimization and control development.

Jan 1, 2014

By Harold L. Gibson, David H. Watkinson

"Volcanogenic massive sulphide deposits of the Noranda Camp cur throughout the Noranda Shield Volcano but are concentrated and along the margins of the Noranda Cauldron. The deposits are realized along synvolcanic faults that also accommodated subsince and controlled the location of eruptive centres. Deposits within e 3 000 m thick Mine Sequence formed during a period of active volcanism and subsidence coinciding with the onset of two cauldron subsidence cycles. The Noranda Cauldron was a restricted site of 10malously high heat flow and structural permeability that favoured e development of a high-temperature hydrothermal system. Metals may have been derived from leaching of aquifer rocks by convecting a water or directly from a shallow underlying magma chamber, now presented by the Plavrian Pluton, that was at its highest position !thin the crust during cauldron subsidence. The deposits formed rough a combination of sulphide precipitation from exhaled fluid td replacement at and below the seafloor in a manner analogous to ose on the modern seafloor.RESUMESi les dépôts de sulfures massifs volcano gènes du camp minier de ~uyn-Noranda sont présents dans les différentes parties du volcanluclier de Noranda, ils se trouvent concentres toutefois, en plus ·and nombre, sur le pourtour de la caldeira (cauldron) de Noranda. ~s dépôts sont localises le long des failles synvolcaniques qui ont cilite la subsidence et contrôle la position des centres d’éruption.~dépôts situes dans la séquence des mines (3 000 m d’épaisseur) sont formes durant un épisode d' activité volcanique et de subsiden qui coïncide avec l' amorce de deux cycles d' affaissement de la rldera (cauldron) de Noranda. Celle-ci Jut le site exclusif d’unflux : chaleur anormalement élevé et d’une perméabilité d’origine cucturale qui ont favorise le développement d’un système hydrothermal a haute température. Les métaux proviennent soit directement d’une chambre magmatique situee afaible profondeur, so it d’un lessivage des roches de l’aquifère par l’eau de mer circulant par convection. Cette chambre magmatique, représentée maintenant par le pluton de Flavrian, se trouvait à son niveau le plus élevé dans la croute au moment de l’affaissement de la caldeira (cauldron). Les dépôts se sont constitués par un mecanisme combinant remplacement et précipitation de sulfures à partir des fluides exhalatifs, au niveau ou au-dessous du plancher océanique, de la même manière que se forment de nos jours, les dépôts de sulfures massifs au fond des océans."

Jan 1, 1990

By E. Haccuria

Due to the growing share of electrical cars, the use of lithium ion batteries significantly increased. Recycling of these batteries is essential to safely dispose hazardous materials as well as to recover valuables (Cu, Ni, Co, etc.). In order to optimise the recycling process, accurate information is required on the slag phase equilibria for battery smelting. The slag is a multi-component system containing alumina from the battery cases, silica and lime from fluxes, and manganese and lithium from the electrode materials. The present study accurately determined the phase equilibria in the "MnO"-Al2O3-SiO2 sub-ternary system at metal alloy saturation. Particular attention was given to the accuracy and reliability of the final results by highlighting the different reaction pathways, mass transfer- and reaction mechanisms taking place in the system during experiments. This attention enabled improved experimental methodology and measurements. Based on the present study, further measurements will be undertaken in the quaternary "MnO"-Al2O3-CaO-SiO2 system at low "MnO" concentrations, which closely represents the future recycling industrial slags.

Jan 1, 2014

By S. Pauly, U. Kühn, J. Eckert, I. Kaban, G. Wiehl, F. Silze

In the present work, the effect of Ga on the wetting behavior of the Cu-rich braze filler CuGa10 (wt.%) on the steel 304L was investigated. For this, the macroscopic and microscopic effects governing the wetting of pure Ga, pure Cu and CuGa10 alloy (wt.%) on the austenitic steel were analyzed and compared. Contact angle and surface tension measurements were carried out by means of the sessile drop technique and, in addition, the phase formation at the interface was determined. Pure liquid Ga spreads on 304L, which supposedly is related to the formation of intermetallic Fe-Ga phases growing into the liquid Ga. Depending on the annealing time, FeGa3 and Fe14.5Ga12 were identified. In contrast, CuGa10 as well as pure Cu show secondary wetting on the steel surface. Especially, liquid Cu prefers to spread laterally and vertically along the grain boundaries of the steel substrate. In spite of rather similar mechanisms, CuGa10 wets 304L steel at lower rate than pure Cu above the liquidus temperature.

Jan 1, 2014

By Jerry Handford

Investing in the Development of our Future Workforce ?Collaborative partnerships with educational institutions, industry associations, governments and other businesses. ?Programs: »Co-op / Discipline Student Program »Trades Development Initiatives »Operator Training Programs »General Student Program »Careers Next Generation / Community Careers Co-operative

May 1, 2006

By G. Kordosky

The experience of one plant regarding degradation of copper solvent extraction reagents in the presence of 20 to 30 g/1 nitrate in the leach solution was described at Cobre 2003. However, little information is available about the degradation of copper solvent extraction reagents where the nitrate concentration of leach solution is much lower. Analysis of plant organic samples taken from an operating copper SX plant over a long period of time shows that small amounts of nitrate in the leach liquor can be a significant contributor to reagent degradation provided certain other conditions are present. These conditions are discussed and cautionary suggestions on copper SX plant operations in the presence of even low levels of nitrate in the pregnant leach are made based on industry experience with copper solvent extraction plants and copper solvent extraction reagents.

Jan 1, 2007

By G. B. Harris

A new process for the recovery of copper and associated base metals from a polymetallic massive sulphide ore is described. The massive sulphide contains copper and especially nickel sulphide in a mineralogical form which negates both good recovery and high grades in concentrates using conventional flotation methods. Flotation concentrate processing and smelting from this ore is therefore probably not an economically viable option. Utilising the properties of high concentration chloride brines, a flow sheet has been developed and tested whereby the recovery of all of the metals and some of the power requirements for the plant itself can be derived from the ore. The new process overcomes the less-amenable-to-flotation ore characteristics, and provides the opportunity of economic processing in remote locations where the dependency on fossil fuels is both a logistical and an economic concern. The Ferguson Lake deposit of Starfield Resources in Nunavut, Canada, is the subject of this paper, which focuses on the leaching and copper recovery unit operations of the proposed flow sheet.

Jan 1, 2007

By Michael Li

Paste backfill as a means of supporting underground mining is gaining popularity. Despite this trend, engineering and design of mine paste backfill systems are still largely based on empirical methods rather than established scientific principles. Because of a lack of sound understanding of mineral paste flow, some degree of trial and error is often involved during commissioning and operating of new paste fill systems. New operations often have to be built with flexibilities and contingencies, escalating the overall project costs. This paper reviews the applicability of some scientific and engineering principles to mineral paste flows. Recent experimental data are used to illustrate important points. The phenomenon of mineral paste flow is examined under the context of improving the efficiency and reliability of underground delivery. Gaps in our understanding of mineral paste rheology are pointed out and from those some future research directions naturally emerge. Status and problems of the current engineering and design practice are also briefly discussed.

Nov 1, 2002

By Shoma Sinha, Nirmal K. Sinha

Deformation in a material at any temperature is known to consist of two major components - a reversible (elastic) part and an irreversible part (often called plastic). What is not universally known is the fact that at high temperatures greater than about 0.4Tm, where Tm, is the melting point in Kelvin, the reversible part includes not only elastic but also a delayed elastic (recoverable but time dependent) component. A very simple computational model is presented here for a constant-strain stress relaxation test (SRT) on the basis of a three-component constant-stress rheological equation derived from strain relaxation and recovery test (SRRT) data. It is shown that the rapid stress reduction during the early periods of relaxation when the stresses are high is governed primarily by delayed elasticity irrespective of the imposed strain level. This is in contradiction to the popular concept prevailing today. The asymptotic approach to a quasi-stable stress rate at longer times and lower stresses is, however, controlled by viscous flow (power-law creep). The validity of the theory is examined by comparing the predictions with experimental results obtained for a titanium-base alloy Ti-6246 at 0.45Tm.

Jan 1, 2004

By Michio Okada

Dissociative adsorption of hydrogen (deuterium) on thin gold films grown on Ir{111} surface has been studied with temperature-programmed desorption using a quadrupole mass spectrometer and nuclear reaction analysis. Thin Au{111} films are epitaxially grown on Ir{111}. Surprisingly, H2 (D2) can dissociatively adsorb on these Au{111} films, although it is well known that Au surfaces are noble enough not to dissociate hydrogen molecules [B. Hammer and J.K. Nørskov, Nature 376, (1995) 238]. We attribute this to the sensitivity of hydrogen to changes in the local surface properties, e.g., electron localization (the narrowing of the s-band, the s-band center model), which could explain the upto now unexpected high for the reactivity of a thin Au{111} surface. Moreover, we found that H (D) atoms can be confined into a Au thin film and/or the interface between an Ir surface and the thin Au film. We demonstrate how anomalously reactive thin Au films grown on an Ir surface are, and also compare the Au films with Ag films grown on Ir to test the validity/generality of our proposed s-band center model.

Oct 1, 2003

By M. Okada

Consumption of refined copper in Asia, especially in China and India, has soared, and the copper price is at its historic height. New smelters and refineries have been built in the region with state-of-the-art technology to meet the unprecedented demands. Supply of copper concentrate, on the other hand, has fallen short of the growing demand for concentrate by the smelters and refineries with expanded production capacities. The shortage of copper concentrate is attributable to the delay in the mining development, caused by the prolonged price slump of before 2005. The mismatch between supply of concentrate and smelting and refining capacities may cause disorderly movement of copper price, and hamper the sound development of the industry. The recent high copper price may prompt substitution with alternate materials. With electrical and thermal conductivity and workability, copper is one of the most customer-friendly materials. It is regrettable for both customers and suppliers if the high copper price would become an impediment to promoting copper use. Some outdated and environmentally unfriendly facilities still operate. In view of recent lower-grade copper concentrate with higher sulfur content, these facilities must reform their equipment to environmental-responsive one. The current level of per capita consumption of refined copper in Asia shows that the demand of copper will further grow. It is necessary to realize stable supply of refined copper and stable copper price, to help developing countries including China and India to economically take off. Hence, it is essential that the development of the copper industry be accompanied by environmentally friendly facilities, and harmoniously increased capacities between mining and smelting and refining.

Jan 1, 2007

By Robert B. Parsons

"As the 1981 annual reports of Canadian mining companies one by one see the light of day, it becomes clear that softer metal prices and rising costs are the main problems which beset the industry today. These problems are certainly not lightened by that familiar monster lurking in the shadows-taxation! Recent taxation trends in Canada, and the existing tax regimes for the mining industry, continue to be a major bugaboo.This examination by ""Tax Notes"" of the impact of current taxation trends on the mining industry is based on a speech delivered recently by Robert D. Brown, senior tax partner of Price Waterhouse, Canada, to the annual meeting of the American Institute of Mining, Metallurgical and Petroleum Engineers in Dallas.IntroductionThe purpose of this paper is to tell a story-and it is a story with a moral. The first thing to recognize is that, with depressed metal prices and weakening western economies, high taxes, in and of themselves, are not really the cause of the Canadian mining industry's present doldrums. However, the character and level of mining taxes in Canada has had a profound influence on the development of the industry over the past decade, and the expectations of what the future holds for mining men in Canada will equally play an important role in the future development of the Canadian industry. Our tax system has, in the past, served as a negative and destabilizing influence in the mining industry: it has contributed to a major short-fall in investment commitments and hence in the contribution which the mining industry can make to the Canadian economy, and the adverse effect on the industry of previous high marginal tax rates was made far worse by the confusing, contradictory and perverse nature of the tax system itself."

Jan 1, 1982

By M. I. Abbas, M. A. Shahin, M. S. Ahmed

"The influence of annealing of galvanized steel (galvannealing) on its corrosion kinetics in a saturated solution of Ca (OH)2 has been studied by means of the polarization resistance method.Galvannealing heat treatment was carried out at 450°C and 550°C for varying times. Annealing at 450°C for 24 hr or at 550°C for 5 hr showed the highest corrosion potential (Ecorr) ~= - 400 m V/ SCE as well as, the lowest corrosion current density (icorr ~= 3 mA.cm-2, while Ecorr and icorr of the unheated specimens were ~= - 1400m V/SCE and == 20 mA.cm-2, respectively.Polarization curves were also obtained for the as-received galvanized specimens together with the galvannealed ones.INTRODUCTIONHeat treatment of galvanized steel (i.e . galvannealing) is carried out at a temperature range of 450°C to 550°C for a time sufficient to convert the free zinc coating to an alloyed one consisting of layers of iron-zinc intermetallic compounds. Table I is a review of the properties of the Fe-Zn intermetallicphases while Figure I is a reproduction - of the Fe-Zn equilibrium phase diagram taken from Hansen.Several authors have studied the formation of intermetallic phases through the interdiffusion of Zn/Fe couples. Their results confirmed the stability of intermetallic phases that could be shown up on the outer surface as a result of galvannealing of galvanized steel.Bernick and Sievertv"" investigated the processing of galvan nealed steel. They found that the galvannealed coating with the best forming qualities consisted of a mixture of Zeta phase and Eta phase."

Jan 1, 1989