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By James R. Lang

The Xietongmen deposit is located 350 km west of Lhasa, Tibet. It is a new, high-grade porphyry copper-gold discovery and the first deposit to be systematically explored by a western company in southern Tibet. In 2005, Continental Minerals Corporation drilled 21,332 m of core in 63 holes and demonstrated excellent lateral and vertical continuity of high-grade copper-gold mineralization over an area 750 m by up to 350 m in size which remains open in all lateral directions. Drill intersections repeatedly yield grades >1% Cu equivalent (based on gold and copper prices) and include 308.5 m at 0.87% Cu and 1.25 g/T Au (1.60 CuEQ%), and 315.6 metres at 0.61% Cu and 1.11 g/T Au (1.26 CuEQ%). Extensive drilling in 2006 will expand and delineate the deposit, and metallurgical, engineering, environmental and socio-economic evaluations will begin. Xietongmen is hosted by volcanic and intrusive rocks of the Gangdese belt, a magmatic arc active between 120 and 30 Ma along the southern margin of Eurasia. Pervasive alteration is dominated by a well-mineralized K-feldspar and biotite assemblage, and by a more peripheral sericitic assemblage also with strong chalcopyrite. Major vein stages include chalcopyrite-bearing quartz, biotite, magnetite and pyrite-pyrrhotite types.

May 1, 2006

By Michael Drozd

"The operation of an activated charcoal system has five separate unit operations. These unit operations have common points for CIP, CIL and CIS system, which vary widely in application.The unit operations are:a. Absorptionb. Desorption (Stripping)c. Acid Washingd. Reactivatione. Carbon Handling (carbon transportation, sizing, dewatering, etc.)Cost optimization starts with the basic operating parameters (design philosophy) set down at the time of engineering design. These parameters undergo almost immediate change due to site specific ore requirements, throughput changes, operator requirements or reagent availability.Activated charcoal is sometimes viewed as simple, uncomplicated reagent that requires not optimization. To some extent, this statement is true, but under most circumstances, if the time necessary to optimize the use of activated charcoal is available, the effort is rewarded with significant savings. CPL-Carbon Link has embarked upon a program of supplying technical support with its activated charcoal. Several operations in the United States have undertaken to have CPL-Carbon Link do an operational survey to determine if potential savings are possible. CPL-Carbon Link has offered to do these surveys for projects that are clients or simply would like to have CPL-Carbon Link review their operation. The information accumulated by CPLCarbon Link is being used to attempt to fashion industry standards so that a common reference point can be established for activated charcoal usage."

Jan 1, 2008

By Norman O. Lotter, Dominic Fragomeni, Jorge Oliveira, Dee J. Bradshaw, Rebecca Monnapula

"The role of mixed collectors in enhancing the metallurgical performance of sulphide flotation processes was reviewed in 2008, and later published as an integrated theory by Lotter and Bradshaw, 2009. The theory proposed that xanthates, dithiophosphates and dithiocarbamates could be synergistically combined in an optimal formula to deliver improved grade and recovery. The approach uses a five-step structure, viz.1. A mineralogical study of the ore to be treated, identifying and quantifying the economic minerals (with hosting and association) and gangue species present.2. Selection of candidate collectors from this mineralogical information and from the known pulp conditions of that operation (e.g. Eh, pH).3. Design and execution of a factorial experiment to estimate and test the main effects and interactions, and to model the response surface for an optimum formulation [Box et al., 1978].4. Use of a High-Confidence Flotation Test platform in the factorial to reduce overall errors and allow for clearer observations [Lotter, 1995; Lotter and Fragomeni, 2010].5. Statistical design of a plant scale trial to measure and validate the gains [Napier-Munn, 1995; Lotter et al., 2009]. Eland Platinum, which was commissioned in November 2007, appointed a team to apply this theory to formulate an optimized mixed collector suite for use in the operation. The West Pit ore (UG2 - Normal ore) was sampled at site and brought to Xstrata Process Support, Sudbury, Canada, for mineralogical and metallurgical testing in 2008. Microprobe and QEMSCAN measurement characterized the type, grain size and textural association of the discrete Platinum Group Minerals (PGM) present. From the mineralogical data, it was clear that a mixture of dithiocarbamate and two xanthates would be a likely reagent suite selection. A factorially designed set of High-Confidence Flotation Tests studying these was performed, concluding that an optimal suite using certain amounts of these collectors was a viable formulation that would advance the grade and recovery performance at Eland above the standard PIBX by approximately 2.13% 4E PGE. The plant trial, which used a form of the replicated block design after Napier-Munn, 1995, and Lotter et al., 2009, exceeded this estimate with an overall PGE recovery gain of 2.48% (absolute basis) and a concentrate grade gain of 26.4 g/t PGE (absolute basis), as well as reducing chrome in concentrate from 2.04 to 1.62% (absolute basis). These gains proved to be statistically significant using the analysis of variance method, and have validated the theory."

Jan 1, 2011

By G. Stokreef, B. R. Davis, M. Kadiyski, Alvear Montenegro, H-P. Loock, V. Montenegro

An optical probe for burner monitoring in copper flash smelting, first developed at the University of Concepcion, is being industrially tested in a collaboration between Kingston Process Metallurgy, Aurubis AG, and Queen’s University. The sensor uses fibre-optics and optical emission spectroscopy to analyze the light emitted from combusting particles in the furnace reaction shaft. Information that can be extracted from the emission spectrum includes the temperature and brightness of the flame, as well as emission lines or bands from excited atomic and/or molecular species. Laboratory proof of concept testing of the sensor was first completed in a continuously fed drop tube reactor using O2/S stoichiometric ratios between 0.8–4.0. These O2/S stoichiometries capture the industrial operating condition, which is typically less than 1. The results from lab testing justified a plant trial of the optical probe, which was done in the Aurubis Hamburg flash furnace in September 2018. From this trial, approximately 31 hours of spectral data were collected and synchronized with furnace operating data. The results from both drop tower test work and the plant trial are discussed with implications for process monitoring in the commercial furnace. INTRODUCTION Flash furnace smelting is a continuous feed, batch tap, pyrometallurgical process. It is used to treat copper sulphide concentrates and small amounts of secondary materials, such as dust generated by the process. O2 enriched air and the concentrate blend are fed into the furnace reaction shaft through the concentrate burner. As the particles fall through the reaction shaft, they heat up and ignite, causing rapid, exothermic reactions that oxidize the iron sulphide, some copper sulphide and impurities in the feed. Reacted particles fall into the settler of the furnace, melt and separate into a matte and slag, while the SO2 enriched off-gas is carried out of the furnace for heat recovery and H2SO4 production. Operation of the furnace is achieved by adjusting a limited number of control variables. The main variables are the blast feed rate, blast oxygen enrichment, SiO2 flux feed rate and CH4 combustion rate (CH4 is used when the chemical energy of the concentrate is low) all measured relative to a set feed throughput. (Davenport & Partelpoeg, 1987; Davenport, King, Schlesinger & Biswas, 2002) The batch tapping nature of flash furnaces makes operation difficult because these control variables impact each other, and product quality can only be measured when matte and slag are tapped from the furnace. This means that operation of a furnace is based on feedback control from matte and slag assays. Because of the time-delay associated with understanding product quality, there is interest in using technology to monitor the combustion reactions that happen in the furnace reaction shaft.

Jan 1, 2019

By Kathleen A. Altman

"This paper supplements the information provided annually at the Canadian Mineral Processors Operators Conference regarding the education of Mineral Processors in Canada. The purpose of the paper is to provide information regarding the engineering accreditation process in the United States and the universities that offer programs in Mineral Processing and Extractive Metallurgy in the U.S.There is a critical shortage of trained Mineral Processors and Mining Engineers world wide. The Society for Mining, Metallurgy and Exploration (SME) formed a task force to evaluate the national needs for trained engineers and to track the number of engineers who graduate from U.S. universities each year. The statistical information for Mining Engineers is well-developed. The current effort is to assemble similar information regarding students who graduate with expertise in Extractive Metallurgy and Mineral Processing as well as to explore the limitations of the accreditation system in the United States and its impact on the education of Mineral Processors. The long-term objective is to develop a data base regarding Mineral Processing programs and Mineral Processing graduates that is as complete as the one that has been maintained by the Canadian Mineral Processors.INTRODUCTIONIn the United States engineering curricula are accredited by ABET, which was formerly known as the Accreditation Board for Engineering and Technology. The objective of ABET accreditation is to ensure that educational programs in applied science, computing, engineering and technology meet quality standards set in conjunction with the professional organizations that represent professionals in the industries which hire students graduating from those educational programs. For example, the Society for Mining, Metallurgy and Exploration (SME) is the lead society for accrediting Mining Engineering programs in the U.S. For Materials Science and Metallurgical Engineering programs, the lead society is The Mineral, Metals and Materials Society (TMS). SME is a cooperating society for accrediting Metallurgical Engineering programs. Cooperating societies for the accreditation of Materials Engineering include the National Institute of Ceramic Engineers (NICE), the American Institute of Chemical Engineers (AIChE) and the American Society of Mechanical Engineers (ASME)."

Jan 1, 2008

By Staff

One hundred thousand miles of flying over the North country without a single air casualty; much of it over virgin territory probably never before visited by white men; some of it over regions that abound with possibilities for minerals; all of it effective, for exploration and the establishment of bases and supply-stations, and for the carrying of men and their tools and provisions- this, briefly, is the record of Northern Aerial Minerals Exploration, Limited, a Canadian company organized Jess than nine months ago, which has been functioning, without interruption, during spring, summer, and now into winter. Our planes have ranged from the Alaskan boundary on the west to the Labrador coast on the east, and from the Transcontinental railway north to the Arctic circle. Our prospectors, carried on trips of hundreds, and occasionally thousands, of miles, have gone over large sections of country which were never before explored, and at the end of the prospecting season the Company finds itself in possession of several groups of important gold claims, which look most promising. In addition to this, we have been in contact with deposits of almost every known mineral.

Jan 1, 1929

By Yannis Faitakis, Simon Bergeron

"This paper describes the implementation of model-based predictive control (MPC) on a vacuum heat exchange network at Alcan's Jonquière Complex. The plant produces alumina from bauxite ore using the Bayer Process.The MPC system was commissioned in 2000, by Alcan personnel and an Advanced Control Engineer from Matrikon. The application has achieved an uptime of about 97%.The benefits were:• Energy savings : 0.5% - live steam reduction• Reduced variation: standard deviation of key temperatures reduced by 50%• Plant throughput increase: via the automated use of surge tanks• Decreased supervision time: by plant operations• Faster and easier diagnosis of problems and plant constraintsThe benefits were higher than expected with a payback time around 12 months.The purpose of the vacuum heat exchange network is to recover energy from a hot stream (pregnant liquor) by transferring it to a cold stream (spent liquor). The system is very tightly coupled, and the main constraints of the multivariable control system are: • to control the many tank levels involved in the process (8 tanks)• to maximize the temperature of the heated streams (spent liquor)• to prevent cooled streams (pregnant liquor) from cooling to below a minimum temperatureThe system includes 9 manipulated, 14 controlled and 2 feedforward variables.The advanced control implementation runs under an expert system environment and provides added flexibility to the overall control strategy."

Jan 1, 2003

By Gabka T., R. E. Gregorczyk

Work to improve employees' behavior in Głogów Copper Smelter began in 2009. It has been noted that over 90% of accidents at work are attributable to human reasons. At that time, a series of external workshops was contracted based on exercises conducted by a psychologist trainer with supervisors. Having trained about 300 employees, an observation of employee behavior at workstations was started as part of the control of risk reduction measures. As a result of the above actions, the number of accidents was reduced by half between 2009 and 2017. Currently, internal workshops for communication improvement for behavioral auditors are conducted by the employees of the Smelter. Named: "I observe, react and communicate" and aimed at further mastering the elements of the safety culture in Głogów Copper Smelter. INTRODUCTION KGHM Polska Miedz is an integrated mining and smelting copper producer based in Poland and operates on the international metal market. KGHM, with annual production of over 500 thousand tonnes of copper, holds a middle position in the world ranking of copper producers. At the same time, in Europe it is the largest producer of copper from its own ore deposits, possessing its own integrated production structure, from underground mining operations to final, top-quality product. It is also worth mentioning that KGHM Polska Miedź is one of the largest Polish exporters and, apart from copper, is a significant primary silver producer in the world. The mission of our company, consistent with its strategy, is to produce copper and silver in a safe mode for workers and the environment, with reduced environmental impact. Therefore, "Głogów" Copper Smelter operations are continuously focused on the creation of safe working conditions, and minimizing the negative effects on the environment. The company meets the requirements of an Integrated Management System comprised of the following: Quality Management System ISO 9001:2008 Environment Management System ISO 14001:2004 OHS Management System according to the requirements of BS OHSAS 18001:2007 Being a proud socially responsible company, we are aware that part of an efficient OHS system is to recognize, monitor, prevent, educate and motivate, thus continuously improve working conditions for 2500 employees of Głogów Copper Smelter &Refinery. We clearly communicate that a low accident rate is beneficial for both, staff and the company, and is of utmost importance as a part of our health policy.

Jan 1, 2019

By M. A. T. Cocquerel, M. G. Burcher, J. G. Eacott

"This paper is based on work carried out to examine the feasibility of increasing the smelting rate of two oil-fired calcine-charged reverberatory furnaces . Various constraints prevented physical enlargement of the furnaces and so allention turned to the use of preheated combustion air or oxygen enrichment to bring about the required increase in production. As a basis for further calculation, a furnace heat balance is determined using the smelting metallurgy and combustion data for the current operation. Various other operational data are tabulated and compared with similar data from other operating copper smelters.New heat balances are derived for various levels of combustion air preheat at the current smelting rate, and the effects of air preheat on oil consumption, combustion air and waste gas volumes are tabulated. These data are used to demonstrate the level of increased throughput which would be obtained before constraints in existing gas handling equipment are encountered.A similar exercise for oxygen enrichment is set out, with oil consumption, combustion air and waste gas volumes at various enrichment levels tabulated for the current smelting rate. These data are in turn used to demon strate the smelting rate which would be achieved at a practical level of enrichment before waste heat boiler and gas handling constraints are encountered.The energy implications for both cases are summarized."

Jan 1, 1980

By Steve McAlister, Colin Sprake

"Enhanced gravity concentration machines have been applied successfully in the following areas of precious metal recovery flowsheets:1. Primary Grinding Circuits2. Shaking Table Tailings3. Pre-Concentration of Leach Feed4. Flotation Concentrates -•, Flash•, ConventionalAlthough great progress has been made, the ability to produce directly smeltable concentrates still remains elusive. Even without this ability, centrifugal concentrators are finding wideningapplications in precious metal concentration:1) PRIMARY GRINDING CIRCUITSEnhanced gravity concentration technology has largely replaced jigging as the technology of choice in precious metal grinding circuits worldwide. The benefits of using a centrifugal field to concentrate both coarse and fine gold are well documented but the placement of these machines within grinding circuits is still evolving. Conventional wisdom dictates that the best location for enhanced gravity machines is cyclone underflow on account of the elevated grade found in this stream when compared to cyclone feed or overflow. Plant operating experience at both large and small scale indicates that there are compelling arguments to place ENHANCED GRAVITY MACHINES on cyclone feed instead. At least two new plants, presently in the detailed design stage will incorporate gravity circuits that treat mill discharge or cyclone feed, Teck Cominco’s Pogo and Newcrest’s Telfer Expansion.Current Conventional PracticeThe current stream of choice for enhanced gravity concentration within grinding circuits is cyclone underflow although recent information indicates a swing toward cyclone feed. Here are some of the arguments for treating a portion of cyclone underflow:"

Jan 1, 2003

By Klaus Tietz, Hamish Adam, John Selby, Ian Glazier, Brian Sinfield

"Room-temperature tunable diode laser (TDL) analyzers are gaining in acceptance for highly critical safety monitoring applications in a variety of industries. This paper describes the testing, evaluation and deployment of a laser-based hydrogen cyanide monitoring system at the Campbell Complex of Goldcorp’s Red Lake Gold Mines in Balmertown, Ontario, Canada.A trial, single channel installation was followed by a staged multi-channel installation. Unexpected technical issues with the multi-channel installation were addressed and resolved.INTRODUCTIONLaser-based gas detection has several advantages over existing gas detection techniques (Ballangrud, 1993; Silver, 1992; Bomse, 1995; Table 1). For practical purposes, lasers generate light at a single wavelength. Room temperature tunable diode lasers (TDL) emit light in the near infrared (NIR) part of the electro-magnetic spectrum. Many gases of interest, including HCN, NH3 and others, absorb energy in the near infrared (NIR). Each gas has a unique absorption signature, or spectrum, made up of a large number of individual “absorption lines”. A TDL can be tuned to select a single absorption line of a target gas, which does not overlap with absorption lines from any other gases. Therefore, laser gas sensing is selective and does not suffer from interference from other gases. The single-wavelength nature of laser light also means that laser gas analysers have a linear response over a wide dynamic range.Tunable Diode Lasers (TDL) generate only a few mW of power. However, all this power is concentrated at one wavelength, the wavelength where gas absorption occurs, resulting in high signal-to-noise ratios and short response times, typically of about 1 or 2 seconds (Ballangrud, 1993). This also means that long path lengths can be used, enabling accurate measurements of very low concentrations, even with weakly absorbing gases. Tunable Diode Lasers provide all the advantages of other semiconductor devices: they are small, solid-state devices, operate at room temperature, and have long-term reliability (over 15 years). Currently, they can be obtained for any wavelength throughout the NIR (700nm to 2000nm). Because many gases absorb in the NIR, the technique is widely applicable."

Jan 1, 2011

By F. Dai

Due to difficulties associated with gripping in direct tension, indirect methods are commonly used to measure rock tensile strength. In this work, we adopt an innovative indirect tensile test method: Semi-Circular Bend (SCB) to measure the tensile/flexural strength of Laurentian granite (LG). The static tests are carried out with a servo-controlled material testing machine and the dynamic tests are conduced with a Split Hopkinson Pressure Bar (SHPB) system. Pulse shaping technique is adopted to achieve dynamic force equilibrium in SHPB to facilitate data regression. Finite element method is used to relate the failure load to the tensile strength. Strong rate dependence of the tensile strength is observed. The flexural strength is higher than the tensile strength measured using Brazilian Disc (BD). This difference is rationalized using the non-local theory. To further validate the method, a coupled Finite element/Discrete element method (Fem/Dem) in conjunction with the smeared crack model is utilized to simulate the fracture process during dynamic SCB tests. The resulting fracture patterns are qualitatively consistent with those from recovered samples. Both the experimental and numerical methods have validated the results and this new method is readily to be used for other rocks and other brittle materials.

May 1, 2009

By James A. Finch

"I offer a personal view of what the next 30 years holds for mineral processing. Re-stating that mineral processing will remain a vibrant industry in raw material production, growth opportunities in waste management are identified. The processing sequence familiar now (mining -mineral processing -extraction) will become more interwoven. In situ processing (i.e., milling underground) will evolve from concept to demonstration. Opportunities to exploit physical properties altered in chemical (pyro-and hydro-) processing will present themselves. In primary grinding, the path to AG/SAG milling will progress with little deviation but opportunities in regrinding are wide open. Flotation will see the trend to designing bubble/particle reactors accelerate simultaneously with a vigorous response from mechanical cell suppliers. Gravity separation remains a bastion of the lone inventor but I anticipate that the new lines will come from the waste management business. I finish by examining the ""research cycle"", identifying growth in small ""high tech"" companies and university research centres.IntroductionI have been asked to offer a personal view of""where we are going in mineral processing?"". Gazing into crystal balls is quite a cottage industry as we approach the end of the millennium. Academics are often asked to assume the role of visionary, I presume because it is considered in their mandate, to reflect and philosophize (or, less charitably, because they are considered to have the time). Since this is the 30th Annual Canadian Mineral Processors Operators Conference, I am tempted to suggest the next 30 years as my frame of reference. This is about equivalent to one engineer's career or, given it takes typically 15 years to go from concept to realization in mineral process engineering (Napier-Munn, l 997a), about 2 ""invention cycles"". With this length of cycle, much that is familiar now will remain so over the 30 years.Research and development (R&D) is in response to need. The overarching need in mining is to find new ore bodies. Process developments cannot compensate for a depleting deposit or a declining commodity price. Mineral processing R&D is characterized by incremental gains, aimed at pushing the mine down the cost per tonne league table. Breakthroughs are the exception (flotation at the turn of the century was one). This must be kept in mind when trying to predict the future in our business."

Jan 1, 1998

By P. J. Williams, A. R. Foster

Petrographic studies, assay records, and laser ablation-inductively coupled plasma-mass spectrometer (LA-ICP-MS) analyses of major sulfides suggest nearly all of the gold at the Ernest Henry Cu-Au deposit occurs in the form of native gold or electrum (95-65 wt.% Au); sylvanite and dissolved gold in cobaltite, chalcopyrite, and pyrite make only minor contributions. LA-ICP-MS analyses of the gold contents of chalcopyrite gave from 8 to 139 ppb (mean = 56 ppb), more than an order of magnitude lower than those experimentally determined in chalcopyrite in equilibrium with native gold at the estimated mineralization temperatures (350°-450°C). Gold content is more variable in pyrite (1-400 ppb, mean = 77 ppb) and highest in narrow growth zones of a subordinate type of complexly zoned pyrite wherein it is associated with elevated As, Ag, Sn, Sb, Te, and Bi. Deposition of gold-electrum was closely associated with, but preceded some of the chalcopyrite deposition, as indicated by microtextures and lower bulk Au:Cu ratios in late-stage chalcopyrite-rich veins. Gold grains have maximum dimensions from <1 to 50 micrometers, and are heterogeneously distributed with most occurring in microscale clusters. Fifty-five out of 76 grains recorded in polished sections are in contact with both chalcopyrite and pyrite, and many of the rest are in sites where such a relationship could exist in the third dimension. The dominant textural sites are intergrowths with chalcopyrite in microveinlets cutting pyrite, and on faces of pyrite grains in contact with chalcopyrite. Scanning electron microscopy, electron microprobe analysis, and proton induced X-ray emission studies show that pyrite associated with gold includes complexly zoned, weakly zoned, arsenian, and arsenic-poor types. The textures are compatible with the possibility that most gold was deposited electrochemically as native metal on pyrite surfaces. The textural distribution of gold has important metallurgical implications given that the ore processing circuits at Ernest Henry and most other sulfide copper mines are designed to exclude pyrite (and arsenic) from concentrates.

Jan 1, 2007

By M. Sturzenegger

This paper documents a field survey using long-range terrestrial digital photogrammetry at the Palabora open-pit mine, South Africa, for multi-scale characterization of rock mass discontinuities. Stereomodels covering the entire mine were generated based on photographs taken from a distance of 1600m across the pit, using a series of f=20-400mm lenses. Details on the methodology used and its accuracy are discussed. Preliminary results on discontinuity orientation, persistence and intensity are presented, highlighting the effect of observation scale. The potential uses of long-range terrestrial digital photogrammetry in open-pit mine and large natural rock slope environments is emphasized. The use of an f=400mm lens from distances larger than 1.5km may represent an important step forward in the geotechnical characterization of inaccessible remote rock faces.

May 1, 2009

By Max W. Ball

THE world&apos;s largest known oil deposit lies in northern Alberta. In fact, according to government estimates, the famous so-called &apos;tar sands&apos; of the Athabaska region contain several times as much oil as all the other proved reserves of the world. S. C. Ells, of the Department of Mines and Resources, who has been the Dominion Government&apos;s authority on the oil sands since 1913, has estimated the minimum content of the deposits at 100 billion barrels(!). C. P. Bowie, of the U.S. Bureau of Mines, has published an estimate of 250 billion barrels(2). ?In comparison, the latest authoritative estimate of the proved oil-field reserves of the world is less than 35 billion barrels(3). Out of this tremendous total, perhaps 500 million barrels are commercially available at present-day costs and prices; the remainder must be considered a latent reserve to be used when development costs are materially lower and petroleum prices materially higher than they now are. Mean-while, the 500-million-barrel portion presently available contains more oil than has been found in all the rest of Canada, and constitutes one of Canada&apos;s great mineral resources. Although these deposits have been known to white men since 1788, when Peter Pond, the explorer, found the Indians stewing the oil out of the sand and mixing it with spruce pitch to caulk their canoes, they are only now coming into commercial production. The purpose of the present paper is to describe the deposits, their oil content, their present development, and the possibilities that seem to lie immediately ahead. For the sake of completeness and clarity, the writer has not hesitated to use or to paraphrase material that he has previously published elsewhere in discussing various aspects of the oil sands.

Jan 1, 1941

By O. J. C. Runnalls

"Canada became the world&apos;s largest uranium producer in 1984. That leadership position is likely to be maintained for many years into the future because of a firm production base, many undeveloped known deposits with commercial promise, and a large geologicalpotential for new discoveries.There are some uncertainties on the horizon, principally because of restrictive actions in process within the U.S.A., which are aimed at preserving a deteriorating domestic uranium industry. Should such actions result in import restrictions, for example, there would be a negative effect on foreign producers at least in the short term. Canada may avoid such difficulties under a tentative U.S.-Canada free-trade agreement where restrictions on the import of Canadian uranium into the United States would be eliminated. Over the longer term, demand for Canada&apos;s uranium resources will grow because of the foreseen growth in the world&apos;s installed nuclear power capacity. IntroductionSince the phenomenon of nuclear fission was discovered in 1938, the utilization of uranium has grown substantially. Initially, the principal use for uranium was in the production of nuclear weapons. However, once civilian nuclear power reactors began to be built in the 1950s, an increasing fraction of uranium output was directed to the production of fuel elements for use in electricity generating stations.The cumulative uranium production by those countries in the World Outside Centrally-Planned-Economies Areas, WOCA, during the period 1938 to 1985 exceeded 800 000 tonnes of uranium. Some 60% of that was mined in the United States and Canada, as indicated in Figure 1. In 1986, nearly 80% of WOCA output came from five countries, Canada, United States, South Africa, Australia, and Namibia, as indicated in Table 1 and illustrated in Figure 2.During the past decade the world annual consumption of nuclear energy has more than tripled (Fig. 3). As of December 31, 1986, the world total of nuclear power reactors had reached 394 with a total net capacity of 270 GWe. The thermal output from nuclear power plants in 1985 exceeded 60% of the energy contained in all of the oil produced that year in the Middle East. Thus, nuclear power has already become an important component in the world energy supply picture."

Jan 1, 1988

By Rees J. Llewellyn

Improved product development, assessment methods and evaluation studies of materials for oil sands applications have traditionally focused on low and high stress abrasion and slurry erosion resistance mechanisms, because they were considered to be the predominant wear modes prevailing in oil sands mining, transportation and bitumen recovery. More recently with the very successful introduction of oil sands hydraulic transportation systems, there has been increasing use of crusher systems in which materials of construction are also required to have good toughness and gouging abrasion properties to withstand impact and the severe indentation and ploughing forces that are involved. To assess material property requirements for mitigating this additional wear mechanism, jaw crusher gouging abrasion tests using a modified ASTM G81 procedure, have been carried out on a range of wear materials of interest for oil sands mining service. The method involves a comparison of the wear losses that occur for reference and selected test plates when a controlled amount of standard feed rock is comminuted in a laboratory jaw crusher. Among the classes of material evaluated have been Q&T plate steels, austenitic manganese steel, chromium and chromium molybdenum white irons as plain castings and in laminated forms and also chromium carbide and tungsten carbide overlaid wear plates.

May 1, 2004

By N. Yamazaki

The supply of clean copper ores, which have high copper concentration and low impurities like arsenic, has declined year by year. Therefore, both mine and smelter sides have to consider how to remove impurities like arsenic. We focus herein on arsenic as an impurity because it is an extremely important issue from the environmental point of view. Approximately 150,000 t of arsenic is input into the copper industry every year. A small part of it is mainly treated in the smelting side. For instance, Ministro Hales Limited, which is a mining corporation in Chile, has performed the calcination process to remove arsenic from ore with high-arsenic content. In the process, flue gas is washed by water, and the final residue is treated by a hydrometallurgical process. Many processes for arsenic removal in various stages have been proposed, and several bottlenecks exist to achieve it. One of the difficulties encountered is getting an assessment of the process, which depends on the countries and/or areas of operation. The standardization of the assessment procedure will be desired in the near future to keep the same environment standards all over the world, and now is the time to start making discussions on this matter. This will be the first step in making an international assessment procedure for arsenic treatment in the copper industry. INTRODUCTION Using the term “sustainable development” without any scientific basis can give people a false sense of security. Engineers and scientists must analyze the total mass flow of energy and materials and estimate local drain on the environment as well as the global impact of a particular industrial activity to ensure sustainability on this planet. The operations of the mining and smelting industries have a strong effect on the environment even if they provide useful materials for human beings. The copper mining and smelting industries have brought about serious environmental problems in the past. For example, the Ashio mine pollution caused big damage to the agricultural sector near the Ashio area in Japan in the late 19th century. One of the most serious problems at that time was SO2 emission because copper ore is sulfide, and the smelting process basically results to sulfur oxidation. The resource balance from a copper smelter in a year, assuming a total production of 16 million tons, can be summarized as follows: discarded minerals, 30 billion tons; sulfur, 16 million tons; iron oxide, 8 million tons; additional smaller amounts of other metals, electricity, and fuel.

Jan 1, 2019

By Hua-Zhong Yu

Gold is one of the most widely used substrate materials for self-assembly. Self-assembled monolayers (SAMs) prepared from alkanethiols and their derivatives on gold are the most reliable and well-studied systems to date, which have attracted much attention because of interest in two-dimensional molecular assemblies, and of their potential applications in molecular devices, sensors, and functionalized interfaces. Gold electrodes are also very important in microelectronics and electroanalytical chemistry. This work reports the characterization of a new type of gold substrates for self-assembly. The gold substrates are constructed from recordable compact disks (R-CDs) with simple and straightforward wet-chemical treatment, and can be made at desired sizes and shapes that satisfy different experimental needs. In particular, an easy, inexpensive, and reproducible method to prepare self-assembled monolayers (SAMs) on CD-R gold substrates after removing the protective polymer films with concentrated nitric acid was described.

Oct 1, 2003