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The copper electrodeposition from sulphuric acid electrolytes in the presence of Thiourea and Gelatin as additives was investigated by electrochemical noise and cyclic voltammetry in conjunction with the scanning electron microscopy technique. This study was oriented to examine the utility of using electrochemical noise "EN" technique to characterize the electrowinning process and the deposit structure morphology as compared to cyclic cyclovoltammetry "CV", an electrochemical method generally used industrially. Both EN and CV techniques were successful to reveal the effect of different concentrations of Thiourea and Gelatin on copper electrodeposition process. In this study, CV has detected an excess of Thiourea leading to porous deposit. While, the electrochemical noise analysis in the time domain (skewness and kurtosis parameters) as detected the presence of nodules and has given useful information concerning the morphology of the deposit closely related to the macroscopic and microscopic studies.

Jan 1, 2007

By F. Golestani-Fard, A. A. Nourbakhsh

In this paper microstructural development of nitride-Bonded SIC refractories is reported in presence of Al203, Mg() and Urea additives .The samples were prepared by mixing, shaping and firing at 1400-1500°c in a controlled atmosphere furnace. Phase analysis, microscopic observation and mechanical evaluation were taken for microstructural investigations. The strength of samples doped with Al203 was first increased and then decreased at higher amount of Al2O3 additions. The addition of MgO decreased the strength while the urea showed an improving effect on strength. These phenomena could be attributed to microstructural evolution and mainly to liquid phase formation and grain morphology. It was found that the additives such as Al203, MO and urea could modify the microstructure in terms of phase formation and texture modification, which in terms influences the mechanical behavior.

Jan 1, 2004

By S. Kamado

Development of new SF6 alternative cover gas with low global warming potential is strongly desired for melting and casting of magnesium alloys. We have tried to apply several kinds of HFC and HFE gases with low potential from 30 to 950 as protection gases to AZ91D alloy melt in the temperature range of 650 to 800°C. As a result, protective film consisted of MgF2 and MgO is formed on the melt surface and ignition-proof effect is sufficiently obtained at all the temperature ranges even when flow rates of mixed gases containing CO2 as a carrier gas are almost the same as those using SF6 gas. Reduction of global warming potential exceeds 98% at 650°C and 89% at 800°C in comparison with a mixed gas of CO2 and SF6.

Jan 1, 2006

By J. Brent Hiskey

At present, approximately 80 % of the worlds mine production of copper is achieved by smelting and electrorefining. The principle aim of copper electrorefining is to satisfy the large demand for extremely pure copper. It is remarkable that high quality copper cathodes with the required purity (99.99+% Cu, ASTM B115-10) and structural characteristics (i.e. deposit density and morphological texture) are produced from impure copper anodes dissolved in electrolytes containing a variety of impurities. This is accomplished with the proper control of operating parameters such as: current density; temperature; copper and sulfuric acid concentration; agitation; substrate preparation; and the application of electrolyte additives. The basic elements of the electrolysis of copper have not changed significantly over the past 150 years since the early developments of James Elkington. Importantly, our fundamental understanding of the underlying electrochemistry has advanced considerably. This is especially true regarding our knowledge of the mechanistic role of additives during the electrocrystallization of copper. This is a very complex subject and modern electrochemical techniques and the development of surface characterization and imaging instruments has helped immensely in our ultimate understanding of how additives control the deposit structure and morphology. The purpose of this paper is to review the historical development and application of electrolyte additives in copper electrorefining and to examine our current knowledge regarding their use. INTRODUCTION The first transatlantic telegraph cable was completed in August 1858. Regrettably, this cable failed shortly after the initial connections. After several more failed attempts, improvements in materials and copper quality resulted in successful communication between Europe and America on July 28, 1866. In many ways this hallmark event demonstrated the need for high purity copper. The first copper refinery in the world was commissioned in May 1869 in Pembrey, South Wales by partners Josiah Mason and James Balleney Elkington. (Historical Note). The 1865 and 1868 British patents issued to James Balleney Elkington were the foundation for the first commercial production of high purity electrolytic copper (Elkington, 1865, 1869, 1870). This important achievement was made possible primarily by the invention of the dynamo which was based on the fundamental operating principles advanced by Michael Faraday. A symbiotic relationship between copper refining and the dynamo was henceforth established. The dynamo provided electric current for electrolytic refining of copper and the electrorefining tankhouse provided pure copper which was required for the generation and transmission of electricity.

Jan 1, 2019

By Paul D. Young, Michael J. Allan

"The Con Mine has been producing gold continuously since 1938. In 1990 laboratory and pilot plant investigations began into the use of pressure oxidation for treatment of an arsenic trioxide waste product from two previous roaster operations on the property. This led to the construction in 1992 of a 96 ton/day plant to treat a mixture of arsenic waste and flotation concentrate from the existing mill. The plant was commissioned in the fall of 1992.This paper describes experience gained in the commissioning and initial operation of the plant. The unique aspects of treating a hazardous waste product are described including special operating procedures to satisfy environmental and employee safety concerns. The paper further describes modifications made to the process flowsheet, to operating procedures and to materials of construction in the early months of operation."

Jan 1, 1994

By S. K. Sadrnezhaad, B. Hashemi, Z. A. Nemati, Z. Moghimi

Based on the kinetics relationships of a solid - gas model, a software was developed for the prediction of oxidation. Preliminary prediction of oxidation by the software and experimental results of MgO-C refractories were studied and compared. By using the obtained data from this approach, the effective diffusion coefficient, intermolecular diffusion coefficient and diffusion activation energy in the MgO-C refractories, containing various amount of graphite were obtained at different temperatures. First of all, the prediction by the software was very compatible with experimental results, for different oxidation mechanisms in the MgO-C refractories. The results showed that pore diffusion is the predominant oxidation mechanism in this system. The results indicated that when graphite content was above 10wt%, the intermolecular diffusion coefficient was independent from graphite content, and it was closed to a constant value at each temperature.

Jan 1, 2004

By D. G. Dixon

A novel technology for leaching copper from primary copper concentrates has been developed at UBC. This patented technology takes advantage of the galvanic couple between pyrite and chalcopyrite to ensure rapid and complete oxidation of chalcopyrite under mild conditions in acidic iron sulfate solution, without the need for microbes, ultrafine grinding, or chemical additives such as chloride, nitrate, or surfactants. Copper recoveries of 98% or greater can be achieved at 80°C under atmospheric conditions in as little as 4 hours of residence time. The process is selective for chalcopyrite over pyrite, generates near-quantitative levels of elemental sulfur, and is fully compatible with conventional solvent extraction and electrowinning of LME Grade A copper cathodes. In this paper, the fundamentals of the Galvanox ? process are reviewed, and selected results of batch leaching tests on various concentrate samples are presented and discussed.

Jan 1, 2007

By G. Ladouceur

"LOCATIONThe mine and mill are located in Lemoine township which is 20 miles directly south-east of the town of Chibougamau Quebec. Personnel live in Chibougamau and commute to the property over 33 miles of paved and gravel roads. Concentrates are trucked 13 miles to a railway siding on the line connecting Chibougamau and Quebec city.HISTORY Several companies explored the property before acquisition by Patino Mines (Quebec) Limited in 1973. Further exploration led to the discovery of a high grade copper-zinc orebody and the property was brought into production by the above company in 1976.ORE The ore contains 85% - 95% sulphides consisting of chalcopyrite, sphalerite, pyrite, pyrrhotite and minor gold and silver. Argenti tetrahedrite, antimonial silver, native bismuth and galena are also pre sent in very minor quantities. Associated gangue minerals are quartz, carbonates and occasionally chlorite."

Jan 1, 1979

Accountability for profit realized or lost, and responsibility for continued safe operation are the main impetus behind operator training. Efficiency in operation enables production at lower unit costs. An inefficient operation eats profitability of the operation, creating short term losses, and also affecting longer term viability particularly when commodity prices fluctuate and competition erodes market share. Safe operation and efficient operation are ultimately conjoined entities which may not be able to be sustained without dual effort. Training is a very valuable tool to engage operations in adopting more efficient and safe practices. Training requires time, facilities and trainers. One novel way of minimizing both the trainers and the facilities is through the use of Computer Based systems. Included amongst this are Computer based equipment simulators, following an identical philosophy as flight simulators used for pilot orientation and training for different aircraft types.

Feb 1, 2008

By Robert Lamarre

In today?s environment, the availability of production equipment is a must to increase throughput and profits. For a number of mining organizations around the world, spare parts availability is key to achieving this goal. Fortunately, having less production equipment immobilized by a lack of spare parts does not equate to increases in inventory levels or in carrying costs. Advance operations research has shown a number of avenues to increase equipment availability while reducing total investment in stock. The presentation will explore these avenues by focusing on key inventory management changes that can be implemented by organizations to optimize their service and stocking levels. We have successfully applied our approaches in start-up mining projects, in mature projects and in end of life mining operations. We will illustrate our methodology using examples from our work with > 30 mining sites around the world.

Aug 1, 2013

By Mahmoud Shakeri1

Various types of thin-walled structures have been frequently used as energy absorbers to mitigate the adverse effects of impact and hence protect the vehicle structure under consideration when subjected to different loading conditions. Compression tubular structures that buckle in a progressive manner, can be used to advantage, providing inexpensive and versatile, but nevertheless weight and stroke efficient energy absorbers. In this paper quasi-static nonlinear finite element simulations are performed to study the effects of number of corners of the cross-section, wall thickness, plastic hardening rate of material, foam-filler and load angle on deformation mode and mean crushing force of tube. Crush strength increases as the number of corners of the cross-section increases, though it almost saturates for the number of corners beyond 11. Higher plastic hardening rate stabilizes the collapse pattern. Foam-filled tubes seem to have higher critical load angles in oblique loading and display a more stable and gradual decrease in mean load over the transition region. Substantial decrease in the initial peak load and dynamic load at any a given deflection was observed as the load angle increases. The investigation of bitubal arrangements and Multi-cell tubes reveals that these may be preferable to monotubal specimens due to the presence of the inner profiles. In addition, a comparison is conducted between the numerical and experimental results of the mean forces of some special angle elements. Good agreement is obtained.

Oct 1, 2011

By Leslie McHattie, Sadek E. EI-Alfy

"The Maintenance Engineering Department at Carol Mining and Concentrating is currently in the process of introducing reliability concepts such as failure analysis, rework elimination, predictive maintenance, computerized maintenance history analysis, etc. to improve the over-all maintenance function in the mine and concentratormaintenance areas. Some current initiatives include:• Implementation ofan infrared thermographic scanning program.• Ultrasonic inspection of shafts for all critical equipment in the mine and concentrator areas.• Non-destructive testing of all major welds done by maintenance personnel.• Development of an effective vibration monitoring and analysis program for the production equipment in the mine (shovels, drills, haulage trucks, locomotives).• Failure analysis performed by maintenance engineers to identify the root cause of component failures on critical production equipment.• Computerized breakdown analysis to identify the recurring component failures which contribute significantly to high maintenance costs and production loss.• Implementation of a computerized maintenance management information system.This paper will outline the planned implementation ofthese initiatives, and others, and will also cover the status and results obtained to date."

Jan 1, 1992

By Zygmunt Wegrzyk

Poland is rich in hard and brown coal reserves, which have become the most important, and steadily developing, primary source of energy. With 192.6 mill. t of hard coal production and 40 mill. t of exports in 1978, Poland is fourth and second in the world respectively. The paper discusses the various mining methods adopted in the country's history of mining. Particular emphasis is placed on longwails, their mechanization and equipment assembled in the form of fully mechanized face complexes suited for varied geological conditions. Measures to improve the recovery ratio of coal resources are dealt with. investment efforts undertaken in the coal industry are outlined. An account is given of the ever improving techno-economic results of coal mining. The country also exports a wide range of mining equipment and transfers its well-founded technical know-how to others. There are strong cooperative links with many foreign partners.

Jan 1, 1979

By R. K. Singhal

"On the mining side the Canadian oil sands industry has become proficient in excavation and disposal of ore and overburden. Nearly twenty years of mining experience is now behind this industry. While local improvements to existing mining systems and practices will continue, it is believed that some further gains in productivity can be achieved by selectively introducing new ideas from other mining and non-mining industries. This type of technology transfer is vital for over-all cost-effective technology enhancement of oil sands mining operations.Discussed in this paper are the issues of mining equipment, equipment sizing, microprocessor and computer based technol¬ogy as applied to mine-wide data management, automation and remote control and a projection of likely mining systems in the year 2000!This paper reviews the ""state-of-the-art"" in selected surface mining systems and attempts to evaluate the forthcoming technology and its application."

Jan 1, 1989

By A. J. Hyett, R. D. Reichert

"A laboratory and field research program was conducted to investigate the major factors influencing bond capacity of grouted cable bolts. The results indicate that cable bolt capacity most critically depends on the grout uniaxial compressive strength (UCS), the radial confinement, and the embedment length.In the laboratory &apos;split-pipe&apos; tests were conducted using P VC, aluminum and steel pipes to provide radial confinement, and field test sites were chosen in granite, limestone and shale rock masses. For both datasets higher capacities were obtained under conditions of higher radial confinement. A correlation between the two was obtained through a comparison of the radial wall stiffness of the laboratory pipes with that of the field boreholes as measured using a high pressure dilatometer. Cable bolt capacity was found to increase with embedment length though not in direct proportionality.The use of low water cement ratio grouts (<0.40) can increase cable bolt capacities by 50% to 75%. This effect is maximized under conditions of high radial confinement. However, the use of super thick grout paste (0.30 and less) may be both impractical and undesirable, first because of their limited pumpability and second because of their inconsistency in strength. Grouts with a water cement ratio of between 0.35 and 0.40 are recommended for practical cable bolt applications."

Jan 1, 1992

By R. W. Luhning, S. D. Gittins, J .. A. Haston

"The Underground Test Facility (UTF) project operated by the Alberta Oil Sands Technology and Research Authority (AOSTRA) north of Fort McMurray has achieved marked success in field testing mining access and horizontal well in situ recovery of bitumen from the Athabasca oil sands.Mine access has provided for effective placing and operation of horizontal wells in the oil sands from a tunnel system in the underlying limestone. Performance of the in situ recovery process, Steam Assisted Gravity Drainage, has substantially exceeded forecasts made at the start of the project. Over-all results of the program to date show great promise for horizontal well in situ technology as a competitive source of bitumen from Alberta&apos;s vast oil sands deposits. The potential economics of a commercial expansion at the site are reviewed in this paper.IntroductionIn situ recovery o f bitumen from the Athabasca oil sands has puzzled the oil industry for many year s, but a breakthrough appears close at hand. The Underground Test Facility (UTF) project initiated by the Alberta Oil Sands Technology and Research Authority (AOSTRA) has had notable success in the piloting of horizontal well processes, which offer prospects for commercial development even under the highly competitive situation facing the Canadian industry . This paper describes the project briefly and presents the potential economics of commercial development on the UTF lease."

Jan 1, 1990

By Mike Anderson

The annual budget for the repair and maintenance of equipment at Syncrude Canada Ltd is in excess of 450 million dollars. Of this amount, a significant portion can be attributed to the loss of material on various pieces of equipment throughout the operation. In order to effectively battle the different wear and corrosion mechanisms that lead to material loss, it is important to understand how materials behave in the environments in which they are used. Through the work carried out at Syncrude, and work conducted with various external collaborators, significant improvements in both equipment reliability and productivity have been achieved. This paper will review some recent field trails where materials research has demonstrated the potential for significant improvements in equipment run life and reduced maintenance costs. These field trails will demonstrate the need for understanding the interaction between various damage mechanisms and the materials used in different services. The paper will also discuss current areas of focus along with future directions for further work.

May 1, 2003

By K. E. Haque

"Radium is selectively leachable from uranium ores with various types of lixiviants. Among a number of lixiviants tried on Midwest Lake uranium ore, KCl provided the highest per cent of radium extraction (60%-65%). Leach results further confirmed that a certain portion of Ra is not amenable to KCl leaching. More than 99% of the dissolved radium could be removed by treating the KCl leach liquor with barite or with radium selective complex resin (XFS-43230 resin of Dow Chemical Inc.) or by precipitating as RaBaSO4. Uranium leachings from the Ra-preleached uranium ores indicate that radium leaching prior to uranium may be applied as an extension to the conventional or alternative (i.e. acid chloride) leaching process of uranium ores in order to yield environmentally acceptable tailings (in terms of radium in the solids).IntroductionAt present, radium is considered as an environmental issue, particularly for uranium ore mine mill operations, rather than a commercial commodity. Radium was once a highly priced commodity ($180/mg during the first great war) but now it hardly has any commercial value. Its principal applications were in the field of cancer treatment and in the manufacturing of lwninous dials for watches. Nowadays readily-available synthetic radioisotopes are finding applications in place of radium.Because of scarcity and high toxicity, further commercial applications have never been explored.Radium was first discovered and extracted from uranium ore by P. Curie, M. Curie and G. Bement in 1898. Radium is widely distributed in nature but in exceedingly minute quantities. It is one of the daughter products of uranium or thorium and its maximum concentration is 3.3 x 10-7 part/part of U(21). Because of its short half-life (approximately 1620 years) in a geological time scale, its occurrence in nature as a distinct mineral is most unlikely.The details of the original radium leaching process developed by the Curies and Bernont are in the literature. This process essentially involved the roasting of uranium ore with caustic. carbonate followed by sulphuric acid leaching. The precipitated RaSO4 and BaS04 were treated with boiling Na2CO3 to convert them into the corresponding carbonates which later were dissolved in HCI. RaCI2 and Ba02 were separated and concentrated from the chloride liquor by fractional crystallization. But, in the course of time several modifications were made or proposed to the original process. Regardless of the process employed 226Ra extraction from the uranium ore was seldom better than 90%, and further as much as 20% 2URa loss took place during the concentration and purification process."

Jan 1, 1987

By Orlando Rojas, Javier Pizarro, Romke Kuyvenhoven, Francisco Soto

"The concept of geometallurgy has been extensively mentioned and used in the mining industry in the past years. However, each mining firm has a different understanding of what geometallurgy means, and its actual value varies significantly from site to site. Even in the case of properly constructed geometallurgical models, it is fairly common to observe a sub-utilization of the model in the actual operation, because of its low production forecasting capability on the short term. This disconnect between the geometallurgical model and operations is typically caused by a lack of tuning between the original model and the actual plant operation. Also, the absence of procedures and other standards for reconciliation, affects the confidence and the predictive quality of the model. The geometallurgical model should consist of three different levels: (I) adequate capture of information, (II) data analysis and modelling, and (III) development of the block model. Once the geometallurgical in-situ model is finalized, a process model should be developed of the plant at industrial scale, in order to scale up the in-situ geometallurgical parameters from their base or standard condition, to the actual operating reality of the plant. Finally, the stage of reconciliation will close this process, assuring that any deviation between the geometallurgical model and the actual plant operation is not due to lack of tuning, but due to operational issues such as unattended maintenance requirements or poor process control in the operation. The methodology as described in this paper has been applied at several large mining sites in Chile. The paper presents the characteristics of the proposed methodology, and quantitatively describes its benefits with examples from actual operations.INTRODUCTIONIt probably is fair to say that geometallurgy became widely used in greenfield projects in the Andes region during the mining boom of the 90’s, when massive orebodies were studied and developed, and upfront metallurgical characterisation proved its use for accurate economic evaluation including estimates of plant throughput, energy consumption, final product quality and overall recovery. A few examples of such greenfield studies for concentrator plants in the 90’s are Minera Los Pelambres (Antofagasta Minerals, Chile), Minera Escondida, Laguna Seca (BHP Billiton, Chile), and Rio Blanco (then Montterrico Metals, Peru). Large size hydrometallurgical operations such as Cerro Colorado, Quebrada Blanca and Lomas Bayas (all in Chile), also recognised early on the importance and value of relating ore mineralogy, geological characterisation and metallurgical behaviour."

Jan 1, 2016

By A. Sutherland Brown

"The ProblemMany science activities receive substantial funding from governments without much direct economic benefit accruing to state or individuals. In contrast, the search for knowledge has never been an acceptable so le justification of geoscience activity, perhaps because of its utility right from its inception. William Smith&apos;s geological activities were embraced because of their usefulness in building canals. Utility has been expected ever since.For decades it has been accepted at senior level s of government, without much understanding of the process, that geological surveys are necessary as a basis of resource evaluation and utilization. Recently, government treasury board s, staffed with economist s, have questioned these near axioms and in many cases the budget s of geological surveys have reflected their stone y-eyed appraisal s. Are government surveys necessary? Can their functions be reduced? Can some or all of their functions be privatized?Government geologists have been muted in trumpeting their successes outside their own ranks. Companies have been reluctant to give specific public feedback on the work of government surveys that have truly aided or guided them toward discovery. Lack of acknowledged linkages between survey work and discovery has dogged survey managers in budget reviews. Impoverished surveys cannot perform adequately so the circle is completed and the doubters&apos; prophecy fulfilled. This is the genera l problem; British Columbia is the archetypical province."

Jan 1, 1986