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By Binxu Zhaug, Mark Jolly, Xiaojun Dai

"In conventional investment casting process of aluminium alloys for the application of the aerospace industry, to assure the quality of the final casting, usually the foundry uses large runner system which results in low yield, high energy consumption and high GHGs emission. In one case of this investigation, the yield is between 5 ~ 10% which means that the current casting process wastes large amount of energy and generates lots of scraps. By applying a new casting method, the bulky runner system and the melting/holding time are significantly reduced, the quality of the casting is improved, and in the meantime the related energy consumption and GHGs emission are significantly decreased. In the investigation, the energy efficiencies and GHGs emission between the current and traditional processes are calculated and compared.1. IntroductionAs one of the conventional casting process, Investment Casting Process (ICP) and its applications can be traced to thousand years ago [l]. In current casting industry, ICP still plays an important role in the production of small and precious castings with high quality requirements in automobile and aerospace industries. Both casting quality and manufacturing costs which mainly consist of energy costs have crucial effects on the competitiveness of castings in the market. In the production of aluminium alloy castings using ICP, the energy cost and energy efficiency of a casting facility depend mainly on the efficiency of its melting and heat treating performance. In association with the two performances, more than 60 % of the total process energy costs are symbolised in a typical casting facility [2]. Additionally, in conventional ICP of aluminium alloys for the application of the aerospace, to assure the quality of the final casting, typically the foundry uses huge runner system including big risers/feeders which cause low yield, creates lots of scraps and generates high energy consumption. Consequently, there are huge opportunities for casting industry to choose the best practices for potential energy saving. Furthermore, the reasons such as the stringent limitation of environmental legislation in Europe and the pressure of the rising energy price force the casting industry to reduce the energy consumption and greenhouse gases (GHGs) em1ss10n."

Jan 1, 2012

By Jarrod Bonsmann

"This paper presents the results of small scale testing to examine the effect of various importantparameters on the response of a vehicle due to the detonation of an explosive charge buried inthe soil below the vehicle. In particular, we were interested in examining what effect change instandoff distance, change in mass, and change in surface area would have on the loading applied.We examined the impulse delivered to the target in all cases and for the change in mass andchange in stand-off distance we examined impulse, kinetic energy, and acceleration."

Jan 1, 2012

By Timothy Fogarty, Gregory Poole, Roger Reeder, David Switz

This project involved the construction of a new pump station and intake structure at an existing water treatment facility. Although the project involved a significant amount of rock removal, the specifications said no blasting.

Jan 1, 2012

By R. E. Mitchell

The environmental impact assessment (EIA) is the accepted method for evaluating proposed mining and other industrial projects to obtain regulatory approval and to help companies plan for responsible development. Another increasingly common evaluation system for proposed projects is the environmental, social and health impact assessment (ESHIA). An ESHIA differs from an EIA for its generally more comprehensive and inclusive approach to evaluating potential impacts, such as on public health, and other features such as an ecosystem services approach to assessing biophysical and community impacts. An ESHIA may also be required by certain lenders for financing major projects. In this paper, EIA standards for the province of Alberta, Canada are discussed and compared to ESHIA. It concludes with several recommendations for consideration.

Jan 1, 2012

By D. Noon

Mine production crews and drill-and-blast crews may be exposed to unexpected movement of ground when working under pit slopes. Without specialist geotechnical advice and appropriate measurement systems, mine crews are faced with conducting risk assessments and relying on subsequent controls that may or may not be adequate to ensure their safety. Mine crews need an ?early warning? monitoring system to give them the confidence that they will have time to walk out of the danger zone if the pit slope begins to move. Slope stability radar technology is used by mine geotechnical engineers to assess overall slope stability over an extended period, typically days or weeks, and to critically monitor slopes that are actively moving and may become unsafe. The complexity of slope stability radar allows for geotechnical engineers to assess movement types and movement rates across multiple work areas of a mine from long ranges, with alarm capability to a central location. However there are many mine work areas where production and drill-and blast crews are not adequately covered or alarmed by slope stability radar systems. What is required is an easy-to-use, short-range, fast-scanning tool that can be operated directly by a work crew and can provide a local alarm with sufficient warning when a wall movement occurs within the work area. The Work Area Monitor (WAM) concept has been developed specifically to be operated by a mine production crew. The system comprises a sensitive, fast-scanning radar coupled with a high-resolution camera, built into a mine-standard light vehicle. The system has been designed specifically for ease of use with the output being a local area alarm to warn workers of slope movement in their vicinity, as opposed to the broader pit monitoring and long-term deformation measurements of the known slope stability radar systems.

Jan 1, 2012

Since 2001, the Hybrid Stress Blast Model (HSBM) project members have developed a software suite to model the complete blasting process from non-ideal detonation to muck pile formation. To preserve the physics and improve solution time, the breakage engine uses a combination of analytical models and 2D axisym-metric finite differences to model near-field crushing, coupled to 3D discrete lattice fracturing and distinct element numerical methods to model throw and muck pile development. The model has been validated by comparison with laboratory and field tests in kimberlite. Multiple blasthole simulations are used to demonstrate how changes to blasting parameters can influence downstream efficiencies. Case studies of wall control blasting show that the presplit design must balance the two opposing effects of increased damage with increased charge and decreasing attenuation of the seismic waves with decreasing charge. Modelling of decoupled explosives needs further development. Reducing the charge towards the back of the trim blast results in a much more significant decrease in back damage than altering the timing. The model demonstrates how separation along the weaker planes in a jointed rock can coarsen the fragmentation, leading to inefficient beneficiation, and extends the damage to a distance of at least twice the burden behind from the blasthole, severely compromising the wall stability.

Jan 1, 2012

Software exhibitors at MINExpo will feature the newest, the best, the most comprehensive computer-based tools available to get minerals from the ground to the market. From the ?cloud? to the pit, the variety that will be featured is almost limitless ? a digital tool for every phase of the mining lifecycle. Blue Sky Network SkyRouter brings the Blue Sky Network to the cloud. Using its interactive Web portal, SkyRouter, with detailed mapping and integration with Google Earth, the Blue Sky Network links enterprises to personnel and assets anywhere on earth through Iridium satellites. The cloud-based solution is designed to support connectivity with remotely dispersed mobile assets, including Blue Sky?s dual-mode GSM and Iridium tracking and communications services. This enables seamless connectivity with assets in problematic cellular reception areas, where only 10 percent of the Earth is covered, and in remote locations.

Jan 1, 2012

By Ragnhild E. Aune, Shahid Akhtar, Reza Beheshti

"The potential use of Black Dross (BD) as a raw material for the production of refractories, fluxing agents and glasses is the main motivation of the present study. Heat treatment experiments were carried out in Ar, and under reduced pressure (20 Pa), to evaluate the salt removal efficiency. The chemical composition of the BD after heat treatment was investigated by SEM-EDS and XRD analyses. Based on the present results, it is established that the salt starts to evaporate at ˜1273 K in Ar, and under reduced pressure. The salt removal efficiency in a 20 g sample was found to increase in both cases as a function of time and temperature. Moreover, in Ar the chlorine concentration was lowered to 0.3 wt% after heat treatment at 1523 K for 10 hours. Under reduced pressure, however, 0.2 wt% residual chlorine was obtained after 8 hours at 1473 K.IntroductionIt is believed that aluminum recycling in the near future will become the main route of aluminum production [1]. Black dross (BD) that is produced during this process contains, among other things, high amount of salts like NaCl and KCl [2, 3]. Almost 800,000 tons of BD is annually land filled in United States and this number continues to grow with the increase in aluminum recycling [2]. The BD should be dumped in controlled land field and it is costly procedure [4, 5].The water-soluble compounds in BD react with water or environmental humidity and release chlorides into the water and/or generate toxic gases such as H2, CH4, NH3 and H2 S [6-8]. In the Europe, BD is considered as toxic waste and its disposal as landfill is forbidden [8, 9]. After salt removal, the BD is considered to be non-hazardous and can be buried under ground [10].On the other hand, BD do also contains many relatively valuable compounds that may be changed in to useful materials as a result of further treatment [11, 12]"

Jan 1, 2012

The AG/SAG circuit discharge P80 is now increasingly referred to as the ?Transfer Size? or T80 for short. From the literature it is apparent that in circuit design some approaches to the sizing of AG/SAG mills as well as the ball mills that they feed use this parameter. This paper reviews whether the use of the T80 is appropriate in this context. In the course of the review examples of AG/SAG discharge size distributions measured from range of operating circuits are used to illustrate the arguments made.

Jan 1, 2012

By Yafei Xiong, Yue Wang, Guotao Xu, Shuzhong Li, Huaiyuan Li

"The composition, properties and structure of taphole clay with high strength and friendly surrounding used in a new blast furnace with 3800 M3 volume was studied. The developed taphole clay had been applied in the blast furnace for four months, pouring times were 11-13 every day, flowing rate of hot iron was 7.5 t/min and the consumption of taphole clay was 0.49Kg per ton iron, which can make the new blast furnace attach the designed production quickly and decrease the cost of hot iron. The taphole clay is easy to be opened in the channel of hot iron which can be remained in stable shape under the corrosion of slag or hot iron, and it dose not produce poisonous smoke in yellow or dark color in the use process. The development of new taphole clay is useful to improve the work surrounding of the blast furnace.IntroductionIn the iron-making process, the taphole clay's function is filling up the taphole and protecting the formation as well as the growth of the clay in the blast furnace, maintaining the enough taphole depth; simultaneously it is easily to open a hole and knock out the clay. The taphole clay has a good performance of molten slag and hot iron resistance. The traditional taphole clay uses coal tar or carbolineum as a binder, and the performance of taphole clay is good, but it has the black and yellow poisonous smoke, which is harmful for work condition. Through the investigation on the binder's composition and poisonous performance of taphole clay, the environmental taphole clay is developed by some foreign companies, which is named the third generation product with benzene is less than 300ppm, and it has been used in European steel companies. This application of the taphole clay with high strength and environment-friendly using in 3800m3 blast furnace is introduced and the performance is discussed and analyzed in this paper."

Jan 1, 2012

By M. C. Walton, W. Roelofs

ABSTRACT: In most cases, a refractory repair involves dealing with used refractory linings above shoulder height, defining these as overhead refractories. This paper details a method of personnel protection involving a low-pressure inflatable balloon system, installed to prevent the dislodgement and freefall of in-situ refractories. This system has been successfully applied to numerous types of vessels in the process industries in the last three to four years. This paper, prepared for the CIM Conference of Metallurgists held in Vancouver, British Columbia in October 2010, outlines details of the system and gives examples of successful applications.

Jan 1, 2012

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

By G Hope, C Young, R. N. Gow

"The presence of enargite (Cu3AsS4) is problematic in gold processing as it is refractory, increasing cyanide and oxygen consumption, and enviromnentally hazardous. Selective leaching and treatment of the arsenic would prove advantageous to conventional gold leaching methods. The reactivity of enargite samples from Montana, US and Quiruvilca, Peru were studied under alkaline conditions, pH range of 8-13, using a cyclic voltammetry corrosion cell setup. Raman spectra of the surface were taken during and after cycling to compare surface species against theoretical predominance diagrams. Under slightly oxidizing conditions, covellite (CuS) peaks were found on the surface in a short matter of time, above - 200m V vs SHE for pH 9-13, suggesting arsenic leaching, but for longer conditioning times, elemental sulfur peaks were also found, which created a passivating surface layer. By operating above pH 12, under reducing conditions, ~-500mV vs SHE, arsenic can be leached as a thioarsenate (AsS4-xOx3-), without sulfur formation.IntroductionEnviromnental limitations on pyrometallurgical processing of arsenic has pushed the desire to process enargite-, Cu3AsS4, bearing concentrates towards a hydrometallurgical solution. Attempts to process can be broken down into two categories - the co-dissolution of arsenic and copper under acidic conditions or the selective leaching of arsenic under basic conditions. The selective leaching of arsenic would preferably leave behind a chalcocite, Cu2S, or covellite, CuS, phase that would be more amenable to conventional processing methods of the copper and gold industries. These methods employ bi- or poly-sulfides to leach arsenic as Assl· [1-4], hypochlorite leaching [5-7], ammoniacal leaching [8] or fine grinding to mechanically activate the enargite surface and increase normally slow reaction kinetics[9]. This study looked into the surface formations of an enargite electrode under alkaline conditions, in a pH range from 8-13, as it cycled from -1000 mV to 1000 mV vs SHE. The understanding of the formations and under what conditions they form will be helpful in further development of any of the aforementioned processes."

Jan 1, 2012

By K. E. Waters, M. Mirnezami, R. Gauvin, A. Jordens, K. W. Malas

"There is currently very little information on the physico-chemical properties of rare earth elementbearing minerals, or on their processing. With the increasing demand for rare earths, this is something that needs to be addressed. This paper introduces some surface chemistry analysis of fergusonite (YNbO4), and the bubble-particle attachment. Zeta potential measurements indicate adsorption of sodium oleate and, to a lesser degree, potassium amyl xanthate onto the surface, and an increase in attachment to an air bubble is observed at pH 4.5 and 6.5. At a pH of 10.5, no attachment is observed, whether in the presence of the reagents or not. This analysis, although initial, will be used to initiate flotation tests, in order to facilitate the selective recovery of fergusonite. INTRODUCTIONRare earth elements (REE) are increasingly in demand, due to their prevalence in both renewable energy devices and high-end electronics. An article in the New Scientist highlighted the importance of a number of REE, many of which most people are be unlikely to have heard mentioned (Crow, 2011). From batteries (lanthanum and cerium) to magnets (dysprosium and neodymium) and lighting (yttrium), the REE are crucial to the advancement of technology and energy saving devices. For example, neodymium is finding most use in the high end magnets that keep the motors turning that power wind turbines and electric cars. In the case of yttrium, the demand outstripped the supply in 2010, emphasising the need to develop deposits containing this and other REE (Crow, 2011). The impact of our dependency on REE has become even more apparent with the reduction in exports by China, which currently controls 97 % of the world’s rare earth production (Pitts, 2011).With the increasing demand for rare earth elements (REE), there is a drive to exploit the known resources around the world. However, the physical beneficiation of the rare earth element bearing minerals is a subject which will require a great deal of investigation to fill the knowledge gaps surrounding these developing rare earth projects. There are numerous articles on REE mineralogy as well as the hydrometallurgical processing of REE concentrates (Alex, Suri, & Gupta, 1998; Peter Gromet & Silver, 1983; Ring et al., 1993; Schnetzler & Philpotts, 1970; Uda, 2000), however a common feature amongst these resources is the lack of detailed descriptions of the physical beneficiation processes required to concentrate REE-bearing minerals. There is work being conducted into reagents and methods for use in recovering some rare earths from their associated ores (Bulatovic, 2010; Ni, Parrent, Cao, & Liu, 2011), but much more in-depth research is required."

Jan 1, 2012

On Feb. 16, 2012, the Polish coal mining company Lubelski Wegiel Bogdanka S.A. set the world record for daily production from a plow-equipped longwall, with an output of 24.4 kt (26,900 st) of coal from a single face. The company commissioned the first Cat longwall system at its Bogdanka Mine, near Lublin in eastern Poland, in March 2010 and within six months had raised the bar to nearly 17 kt/d (18,700 stpd) of cut coal. Since then, Bogdanka has continued to increase its daily output with a plow face that began mining in the new 7/VII/385 panel last October, taking the world record to new levels. In addition to the record output achievement, the plow face advanced more than 27 m (89 ft) at a 1.63-m- (5.3-ft-) cutting height. ?We thought this achievement would be impossible for any shearer in seam heights as low as this,? said Zbigniew Stopa, vice president of Bogdanka.

Jan 1, 2012

By David J. Roha

"The harsh environment of the Carbothermic Aluminum process makes necessary numerical modeling as a means of process visualization and understanding. A brief survey of the various numerical models, with emphasis on CFD, applied in the development of the process is presented.IntroductionThe environment of the Alcoa Carbothermic reactor is necessarily a harsh one, with temperatures approaching 2100 °C and plenty of reactive dust and vapors. As such, it is difficult to directly observe what is actually taking place. Thermocouples can last for a few minutes but are eventually destroyed. The openings to optical pyrometers become occluded with dust and condensation. Graphite sheathing embrittles, reacts away or becomes clogged with condensate. Dip-samples on steel rods are routinely taken, but their interpretation is often unclear.Those measurements that can be reliably taken are invaluable, but often do not provide a complete picture. Therefore from the very inception of the project both physical and computer based models have played an important role. Modeling provides an intuitive understanding of the processes that might be taking place and in very many cases approach quantitative prediction. I will briefly touch upon computer-based modeling performed at Alcoa over 12 years of the Carbothermic project, with special emphasis on CFD. The explanation of physical models is perhaps best left for those with the greatest familiarity with them"

Jan 1, 2012

By Jorge Alberto Soares Tenório, Denise Crocce Romano Espinosa, Kellie Provazi

"The purpose of this paper is to study metal separation and recovery from a sample composed of a mixture of the spent household batteries main types, using liquid-liquid extraction and metals electroplating. The electrolytes preparation consisted: grinding the waste of mixed batteries, reduction and volatile metals elimination using electric furnace and acid leaching. From this solution were studied the liquid-liquid extraction using Cyanex 272 [bis(2,4,4-trimethylpentyl) phosphoric acid] with tributyl phosphate as extracting agent. After study of solvent extraction and stripping has been recover and separate the metallic ions and with electroplating was recovered the manganese, copper, nickel and cobalt in their metallic forms.IntroductionCurrently has increased the consumption of electronics devices such as mobile phones, laptops, wireless phones, comcorders, etc., especially portable devices that use batteries as a power source, and consequently has increased the disposal of such material.Increased consumption of this devices is caused by several factors including increased popularity of consumer electronics devices, has become essential of modem life. Therefore, recycling of batteries is important because its reduces the waste of raw materias and nonrenewable resouces used in manufacturing these materias and help prevent potential environmental risks associated with improper disposal of these products together with household garbage.The batteries have a very diverse composition, containing metals such as zinc, lithium, nickel, lead, mercury, cobalt, cadmium, iron, copper, manganese and rare earths. Some components may contain hazardous materials such as cadmium, mercury and lead, and can contain acids or bases.This research line is a pioneer in dealing with a single process for recycling a mixture with all batteries types, for only processes that exist in the world are based on the recycling a mixture with all types of batteries, for only processes that exist in the world are based on the recycling of one or two types of batteries [1-4]. This process necessitates the previous separation of the batteries by type."

Jan 1, 2012

In Canada and other countries, legislation dealing with accurate factual disclosure for mining projects is being expanded to include more metallurgical design information. Grinding characteristics, metallurgical recovery of contained metal and environmental hazards associated with tailings disposal will be part of the Canadian package. This paper will examine only that portion of the plant design standard practice that relates to grinding ? in SAG mills and ball mills that grind ore from as received crushed material to final ground product that is fed to downstream plant recovery processes. Since grinding plants represent a significant portion of the overall concentrator cost, accountability in grinding design should no longer be left to chance, opinion, or hidden proprietary information. This is the 21st century. It is reasonable to expect that a factual basis will be needed so that a Qualified Person (QP) reviewing the grinding mill design can understand it. That will also involve how many and what quality of samples are taken to define the characteristics of the deposit, the accuracy of the tests used to measure ore hardness and the method by which the dimensions and power of the mills are determined. If these criteria are not met, the QP may have no choice but to call attention to the lack of convincing information regarding the grinding mill design for the project. At the same time clients are expected to demand getting the correct design information at a cheaper price, results in a more timely way, and accurate design to the point where the risk of tonnage shortfalls are reduced or eliminated. Tables will be presented to show how this can be done to current standards using existing technologies. At the same time it is acknowledged that current standards are ill-defined and that to achieve consensus among those involved in SAG mill design work, it may require that a consortium funded project be set up to establish what tests and methods for grinding design are suitable to meet the new standards for metallurgical disclosure. By running parallel design methods on several major projects over a period of 5 years, the process of how to design grinding circuits will be better understood because the projects will start at the design stage, include procurement of the mills and will end with a benchmark test on the plant. Selecting the samples and the best schedule for doing test work on core samples submitted and mill design, will be discussed in this paper. The issue of completing the grinding design in time for early procurement decisions is on the critical path for most major projects. Discussions between mining engineers, geologists and process engineers are needed early in the development cycle, at the scoping study level (SS), preliminary engineering assessment (PEA), prefeasibility study (PFS), and at the feasibility study stage (FS), to ensure that proper planning for design sample selection is done. Using adequate sampling and testing methods in a timely way allows early procurement of the grinding mills and minimizes project risk.

Jan 1, 2012

By M. van de Vijfeijken

This paper will first give a short overview of the Copper Mountain project in British Columbia, which just has started commercial operation earlier this year. The grinding process with one 34' x 20' SAG mill and two 24' x 39.5' ball mills will be briefly discussed. All three mills are gear driven by a ring gear, dual pinion and two low speed synchronous motors. Copper Mountain has installed on all three mills, the new state-of-the art dual pinion mill drives. All the inherent operation and maintenance features of this drive technology will be discussed, as well as the advantage of having variable speed control also on the ball mills. The installation and commissioning of the mills and drives at Copper Mountain will be briefly reviewed. Finally the first field measurements on these low speed mill drives will be presented, with the main focus on the low mechanical stress impact of these mill drives on the pinion and ring gear, as well as the accuracy of the load sharing between the two motors.

Jan 1, 2012

By A. Azizi, P. Blatter, A. Bouajila

"Due to the high reactivity of sulfide minerals in alkaline cyanide solutions, some parasitic reactions inflict a heavy gold surface passivation and excess cyanide consumption resulting in a dramatic decrease of the gold leaching rate. Atmospheric pre-oxidation was shown to be an effective tool to enhance gold extraction by preventing a passive film from forming on the surface of gold grains. This work aims to highlight efforts undertaken to determine: (1) how gold cyanidation is limited by passivation; (2) what are the reactions and mechanisms involved during gold cyanidation; and (3) how a better understanding of fundamental issues can be used to design a proper pre-oxidation strategy. INTRODUCTION Precious metals (PM), gold in particular, naturally occur in contact within a wide range of sulfide mineral systems. Hence, one of today’s most challenging R&D tasks consists in accounting for the presence of sulfides on the cyanidation behavior of gold. An important body of knowledge reveals that metal sulfides display a range of reactivities in alkaline cyanide solutions (Marsden & House, 2006). Such reactivities are acknowledged to inflict additional utility costs and loss of profits because they are accompanied with higher consumption of cyanide and/or formation of undesirable by-products that are often detrimental to gold leaching rates. Gold recovery in cyanidation is hampered by a multitude of factors, among others: (1) consumption of excess cyanide as a result of the formation of thiocyanate and dissolution of transition (Cu, Fe, Zn, etc.) metals (Habashi, 1967); (2) gold surface passivation by solid reaction products, e.g., Fe(OH)3 (Guo, Deschenes, Pratt, Fulton & Lastra, 2005), sulfur (Dai & Jeffrey, 2006; Jeffrey & Breuer, 2000;) or oxo and thiooxo (SbO33- SbS33-) salts in alkaline solutions (Guo et al., 2005). Because of their energy structure, most of the sulfide minerals exhibit semiconductor properties (Marsden & House, 2006). Therefore, the contact between constitutive sulfide minerals inside complex sulfurous ores entrains electrochemical phenomena in which sulfide dissolution is a genuine corrosion process (Azizi, Petre, Olsen & Larachi, 2010). For instance, galvanic interactions could be initiated between the various constituents within the ore and could substantially increase or decrease the reactivity of some of the associated minerals."

Jan 1, 2012