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By J. Sliwinski, H. Kikutani, J. Atwood, D. Larimer, J. Pyecha

"The Pogo mine start-up milling targets of 2005 are vastly different than the targets of today. Improvements have been driven by unintentional design oversight, continual circuit optimization or optimization due to changing mineralogy. The more significant process improvements to date have occurred in the gravity, flotation and leach/CIP unit operations. Details of the significant improvements are presented along with the impacts to the process.INTRODUCTION Deposit Overview Pogo mine is located along the Goodpaster River, southeast of Fairbanks, Alaska. This deposit sits in the center of the Tintina Gold Province (Figure 1), a region of similar Intrusion Related Gold deposits in Interior Alaska, the Yukon and British Columbia Canada (McCoy et al., 1997). The Pogo deposit is hosted in a rock sequence of amphibolite-grade gneisses intruded by mid-Cretaceous granitic plutons and dikes, which in turn, were cut by and host the auriferous quartz veins of the Pogo deposit.The Pogo deposit is comprised of three distinct zones of auriferous quartz veins spatially adjacent to each other. These are the Liese Zone, North Zone, and the East Deep Zone. The Liese Zone consists of three stacked, massive quartz veins, designated the L1, L2, and L3. Vein thickness averages 3.0 m, with variations from 0.3–18 m thick. The North Zone mineralization is comprised of four veins with more consistent thickness, between 1 and 1.5 m. The East Deep deposit lies northeast of the Liese Zone ore body. It is separated by a post mineralization, quartz diorite pluton. The East Deep Zone is comprised of two stacked massive quartz veins with similar orientation as the Liese Zone."

Jan 1, 2017

By D. M. Rippley

THE St. Lawrence Seaway Project ranks with the greatest engineering undertakings of all time. A summary of major materials going into the construction of this project, shown in Table I, will assist in an appreciation -of this fact. These data relate to Seaway construction only, and it should be remembered that two large-scale power projects are in the construction stage on the St. Lawrence river concurrently with construction of the Seaway. A project of such magnitude as the Seaway would attract widespread interest even if it were being constructed in a remote area. The fact that it is located in a heavily populated and developed section of both Canada and the United States has done much to enhance this interest, and in many ways complicates the problems confronting the engineer in the design and construction phases. Many consider the St. Lawrence Seaway to be a new idea that has developed within the past decade - such is far from the fact, because the St. Lawrence River canal systems have existed for more than a century, and the Seaway Project is but a new, larger, and more efficient version of a continually expanding facility.

Jan 1, 1957

By S. Khallouk, J. Zollinger, J. R. Kennedy, E. Bouzy, B. Rouat, D. Daloz

Titanium aluminides recently replaced Ni-based superalloys as turbine blades in the last LP stage of aircraft engines. To extend their range of use at higher temperature their properties need to be improved, either by alloying or processing. An efficient solution is to reduce the grain size during the solidification process. In the first part of the paper, an overview is given on the possibilities for grain refinement of such alloys, based on literature data and new results. The most efficient grain refinement is obtained with boron addition which leads to boride formations that are detrimental for in-use properties of turbine blades. In this work, the use of the high grain refinement potency of inoculation with non-brittle particles has been used by developing new refractory-based inoculants. The effect of one of these inoculants on grain refinement of an as-cast structure in a Ti-46Al is presented; resulting in a reduction of the grain size by a factor of 3.While less efficient compared to the potency of boron containing alloys, the grain refinement is effective and does not introduce any embrittling particles.

Jan 1, 2015

The influence of joint orientation and joint persistence, on the mechanical behaviour of jointed rock masses under uniaxial compression, has been studied systematically. The joint inclination angle ß was varied from 0° to 90° with an increment of 15°. The joint continuity factor k was taken as 0.2, 0.4, 0.6 and 0.8. The peak strength, Young’s modulus, the complete axial stress-axial strain curves, the cracking process and the characteristic of the fragments, were investigated. It was found that the anisotropic response of the jointed specimens was governed by the micro-mechanism, such as crack initiation, propagation and coalescence, crack opening or closing, and frictional slip of cracks or joints. With the increase of joint continuity factor, the axial stress-axial strain curves change from single-peak to multipeak, the peak strength and Young’s modulus decrease. The specimens with medium joint inclination angle (30°,45° and 60°) has lower energy dissipation and strength due to stepped or shear failure, while specimens with small and large joint inclination angle (0°, 15°, 75° and 90°) has higher energy dissipation and strength due to axial cleavage or crushing failure.

Jan 1, 2015

By N. Ahern, L. Manoukian

"Cyanide is a leaching agent for precious metals commonly used in gold ore processing. Cyanide exists in various forms (including free, complexed as weak or strong complexes, and as ions such as cyanate and thiocyanate), so its detection, speciation and analysis in processing or environmental samples can be complex. This paper will review best practices for cyanide sampling and preservation in the field, interferences and pretreatment methods required prior to sample analysis and analytical methods that are used for cyanide species. Titrimetric, flow injection ligand exchange, spectrophotometric, colorimetric, potentiometric, amperometric, and chromatography techniques will be discussed and their chemistries, detection limits, advantages and limitations will be described.INTRODUCTION Cyanide is well known to be an extremely toxic species. Accurate cyanide measurement in effluent from mines is critical from an environmental perspective. Its measurement is also an important control parameter in the recovery of gold using cyanidation. Cyanide chemistry is diverse and complex, and cyanide analysis can be challenging as a result of and because of limitations in understanding of analytical methods. Various chemical mechanisms can form or destroy cyanide, and the sample matrix or preservation chemicals can also affect analytical results. These interferences make the collection of reliable cyanide measurements challenging and can start as soon as the sample is collected, during laboratory pre-treatment and during analysis. This paper reviews different methods of cyanide measurement. The basic chemistry of cyanide, best practices for sampling and preservation, as well as various methods of analysis will be discussed.CHEMISTRY The complexity of cyanide chemistry is well known (Beck, 1987; Delgado, Botz, Bucknam, Milasovljevic, & Staley, 2008; Botz, Milosavljevic, & Ward, 2013) and is attributed to the ability of cyanide to undergo: •,Volatilization •,Precipitation •,Adsorption •,Complexation with metals •,Oxidation to cyanate, ammonia, or cyanogen chloride •,Reaction with sulfur or sulfide minerals to form thiocyanate •,Redox reactions leading to the formation of cyanogen and cyanate •,Redox reactions (of some cyano complexes) •,Photochemical reactions (of some cyano complexes)"

Jan 1, 2017

By J. A. Cox, R. S. Mattson

"One of the main problems encountered in employing sublevel caving is the inherent high dilution factor. The operating results at Granduc illustrate that this dilution can be closely controlled and satisfactory recoveries achieved, in base metal ores grading less than 2.0% copper equivalent, by using an assay grade control system based on the fundamental draw characteristics. The history of draw control procedures employed since the start of operations provides an effective comparison between this system and one based mainly on tonnage. The transverse and longitudinal sublevel caving mining methods are described and it is shown how improvements in design layout, operating practice and draw control in narrow complex ore zones (12-foot minimum width) have raised the operating performance of the longitudinal system to a satisfactory level."

Jan 1, 1973

By Feng Xue, Mi Xujun, Peng Lijun, Yin Xiangqian, Liu Dongmei, Xie Haofeng, Huang Guojie, Yang Zhen

The Age-hardening Cu-Cr alloys are extensively used in integrated circuit lead frame, railway contact wire, resistance welding electrode and continuous casting mold copper plate, owing to having an excellent combination of high electrical or thermal conductivity and high strength. High temperature performance is very important during the service process. Effect of Magnesium and Zirconium on softening behavior of Cr-Cr alloy are investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). During the softening process in the Cu-Cr alloy, the recrystallization process, grain growth and Cr precipitates coarsening are observed. The addition of Mg or Zr to the Cu-Cr alloy, the resistance to elevated temperature can be significantly improved, owing to being restrained the growth of the precipitates by segregating along precipitates surface. INTRODUCTION Age-hardening Cu-Cr system alloys can be widely uesed in many fileds such as electrodes for spot welding (Hatakeyama et al., 2008; Cheng, Shen & Yu, 2013; Zhou et al., 2016; Chbihi, Sauvage & Blavette, 2012), intergrated circuit lead frame (Hatakeyama et al., 2008; Cheng, Shen & Yu, 2013; Zhou et al., 2016; Liu et al., 2006; Pang et al., Xia et al., 2012; Wang et al., 2009; Huang et al., 2003; Cheng, Yu & Shen, 2014; Zhang et al., 2016; Li et al., 2007) and railway contact wire (Cheng, Shen & Yu, 2013; Zhou et al., 2016; Chbihi, Sauvage & Blavette, 2012; Liu et al., 2006; Pang et al., Xia et al., 2012; Wang et al., 2009; Huang et al., 2003), because it has high strength, good electrical and thermal conductivity. The precipitation behavior of binary or ternary Cu-Cr alloys had been investigated by many researchers (Chbihi, Sauvage & Blavette, 2012; Peng et al., 2017; Batra et al., 2002). In addition, to obtain additional mechanical properties without much deterioration in electrical conductivity, trace addition of alloying elements like Zr, Ag, rare metals (Y and Ce) and Mg are added into Cu-Cr alloy. The addition Mg to Cu-Cr alloy accelerated the process of precipitates nucleation and restrained the growth of the precipitates by segregating along precipitates surface during aging, which enhanced the stability of the deformation microstructure and improved the mechanical properties of the alloy (Zhao et al., 2018). Additional zirconium in Cu-Cr alloy enhances the strength by the decrease in inter-precipitate spacing of Cr precipitates and the formation of Cu5Zr phase (Chihiro, Ryoichi & Kazue, 2008). Owing to the decrease in inter-precipitation spacing of Cr precipitates and to the Ag-atom-drag effect on dislocation motion, the addition of Ag can increase in strength, stress relaxation resistance and without much deterioration in electrical conductivity (Chihiro, Ryoichi & Kazue, 2008). The enhance in strength and electrical conductivity of the Cu-Cr-Zr alloy by adding Ce and Y elements are attributed to removing oxygen and sulfur from as-cast alloy (Li et al., 2006). However, the effect of Mg or Zr element on microstructure and properties of Cu-Cr alloy during the softening process are not clear. Therefore, Microstructure evolution and properties of a Cu-Cr systems alloy were investigated in detail by OM and TEM. The Relationship between microstructure and properties of Cu-Cr systems alloy was also discussed.

Jan 1, 2019

By Shinji Shirakawa

The gold wire bonding technology is widely used for electrically connecting aluminum pads on IC devices to external terminal of semiconductor. In 1960?s, the tensile strength of gold bonding wire was about 100 MPa only. However, recently the wire with 300 MPa in strength has been developed. Since the gold bonding wire was started to use for IC package in early 1960?, the many types of gold bonding wire has been developing continuously in order to meet market?s needs, such as high density, small size and thin type of IC packages. Moreover, electronic equipments were used in automobile applications and also demanded good reliability under severe temperature environment. Thus Au-Pd alloy wire has been introduced instead of the wire with 4N(99.99wt%) purity gold to provide excellent reliability in Au-Al bond interface. The phenomena at Au-Al interface in the high temperature storage have been already explained by several studies as follows. There are five phases of inter metallic compound (IMC) between gold and aluminum. Just after bond gold ball on aluminum pad, Au5Al2 phase was formed and occupied almost all of IMC area. During high temperature storage test, Au5Al2 phase transformed to Au4Al phase, then this phase was corroded by Bromide (Br) ion that was isolated from molding resin. Thus the reliability between Au and Al degraded. In case of Au-Pd alloy wire, the concentrated palladium phase (Au-Pd-Al) was formed at the interface between Au alloy ball and Al pad. The Au-Pd-Al phase prevented from transforming between Au and Al, therefore Au5Al2 phase was hard to transform to Au4Al phase. Consequently the reliability at the interface between Au alloy ball and Al pad was less degradation. However, in recent study using several advanced analysis technique, Au4Al phase was found at the interface between Au alloy ball and Al pad same as the case of conventional gold wire (4N purity gold bonding wire). It was suggested that the formation of concentrated palladium phase (Au-Pd-Al) related the excellent reliability at ball bonding process.

Oct 1, 2003

By Francoi Robert, Andre J. Audet, Alex C. Brown

"The Sigma gold deposit is in a band of deformed metavolcanic rocks that are cut by an irregular mass of porphyritic diorite and by narrow undeformed feldspar porphyry dykes. The gold is in veins consisting mainly of quartz and tourmaline with minor pyrite, carbonate, chlorite, scheelite and free gold. The results presented here concern the structural setting of the ore and are based on a study of the mode of emplacement.Two principal types of veins have been recognized: subvertical and oblique veins. Both types are contemporaneous, mechanically linked and postdate regional deformation. The sub-vertical veins are composed of numerous mineralized lenses that occupy the central part of ductile shear zones of great lateral and vertical extent. Normally, several lenses occur in the same shear zone. The vein material seems to have resulted from incremental filling of openings by repeated vertical movement along rupture planes developed in the central part of the shear zones.The oblique veins are small elliptical lenses of ribboned vein material which formed essentially by progressive vertical opening of oblique fractures. Two types of oblique veins are known: one is restricted to feldspar porphyry dykes, within which they are arranged in an en-echelon fashion; the other is of greater extent and is not restricted to one rock type, but tends, however, to occur in the more competent porphyritic diorite.Vein orientation and mode of formation suggest that both sub-vertical and oblique veins developed during progressive deformation associated with the formation of the ductile shear zones. The latter probably formed in response to a compression that took place late in the tectonic history of the host rocks at Sigma."

Jan 1, 1983

By Francoi Robert, Andre J. Audet, Alex C. Brown

"The Sigma gold deposit is in a band of deformed metavolcanic rocks that are cut by an irregular mass of porphyritic diorite and by narrow undeformed feldspar porphyry dykes. The gold is in veins consisting mainly of quartz and tourmaline with minor pyrite, carbonate, chlorite, scheelite and free gold. The results presented here concern the structural setting of the ore and are based on a study of the mode of emplacement.Two principal types of veins have been recognized: subvertical and oblique veins. Both types are contemporaneous, mechanically linked and postdate regional deformation. The sub-vertical veins are composed of numerous mineralized lenses that occupy the central part of ductile shear zones of great lateral and vertical extent. Normally, several lenses occur in the same shear zone. The vein material seems to have resulted from incremental filling of openings by repeated vertical movement along rupture planes developed in the central part of the shear zones.The oblique veins are small elliptical lenses of ribboned vein material which formed essentially by progressive vertical opening of oblique fractures. Two types of oblique veins are known: one is restricted to feldspar porphyry dykes, within which they are arranged in an en-echelon fashion; the other is of greater extent and is not restricted to one rock type, but tends, however, to occur in the more competent porphyritic diorite.Vein orientation and mode of formation suggest that both sub-vertical and oblique veins developed during progressive deformation associated with the formation of the ductile shear zones. The latter probably formed in response to a compression that took place late in the tectonic history of the host rocks at Sigma."

Jan 1, 1983

By V. G. Papangelakis, G. A. Moldoveanu

"One of the major commercially viable secondary sources of rare earths elements (REE) are the ion-adsorption ores, containing 0.05-0.3 wt% rare earth oxides physically adsorbed on the surface of clay minerals formed during weathering of lanthanide-rich rocks. Although ion-adsorption deposits are substantially lower grade than other types of rare earth sources, this is offset by the easier mining and processing costs and the low content of radioactive elements. The conventional extraction route involves ion exchange leaching with monovalent cation solutions (usually ammonium sulphate) under ambient conditions; during the process, the lanthanides are desorbed and transferred into solution, being replaced by the exchange cation. While ammonium ions are known to perform best, there is increased environmental motivation to investigate alternative lixiviants in order to minimize ammonium sulphate impact via reducing its use without considerable loss in rare earth recovery.The objective of the present research was to screen various cations salts (alkaline and alkalineearth metals present as sulphates, chlorides and acetates, respectively) in order to comparatively evaluate lanthanide desorption levels and provide a theoretical base of the observed behaviour. The overall aim is to gain a better understanding of how both cation and anion may affect the overall REE recovery from ores in order to provide alternative processing routes. The distinct exchange capabilities of cations were explained in terms of differences in cation hydration enthalpy within the same group, i.e. Cs+ > NH4 + > K+ > Na+ > Li+ and Ba2+ > Ca2+ > Mg2+. For the same cation, it was determined that REE extraction efficiency follows the order sulphate > acetate > chloride, based on dissimilarities in constants of formation values. Various process implications scenarios will be described based on using mixed cations and anion matrices."

Jan 1, 2016

By N. Djilali

Many of the transport phenomena encountered in proton exchange membrane fuel cells occur intrinsically at the microscale level. Physically representative models that fully account for the salient physico-chemical and transport processes in PEM fuel cells are necessary to achieve truly predictive models that can be used with confidence to: (i) gain a better understanding of in-situ processes and couplings, (ii) explore new concepts, and (iii) support design and optimization. The development of more general, rationally based macroscale models requires use of knowledge on the microscale level to provide guidance, and to determine the required parameters and coefficients (model "constants"). In this paper we present a new membrane transport model, the binary friction membrane model (BFM2), recently developed to account for coupled protonic and water transport in polymer membranes. This general model is based on rational and physical consideration, removes several of the limitations of the empirical models used to date, and is formulated for all purfluoro-sulfonic acid membranes. The use of the BFM2 in a fuel cell model is illustrated highlighting significant performance predictions compared to existing empirical model. The second part of the paper addresses the fundamentals of two-phase transport in hydrophobic gad diffusion media. Computational and experimental visualizations resolving the microscale dynamics of water transport between the fibres of a GDL are presented, revealing transport mechanisms that are, contrary to assumptions used to date, dominated by fingering and channeling.

Jan 1, 2005

By T. P. Johnson, A. Vathavooran

"Conventional mining operations can produce a wide range of wastes containing gold and other precious metals but which are less suitable for processing by traditional methods. There are also types of ore that do not fit easily into a traditional processing flowsheet, e.g. because the refractory nature of their minerology or the combination of valuable metals is less suitable for traditional processes. Nevertheless, these potential sources of valuable metals remain unexploited resources that have attracted growing interest in the metals and mining industries over recent years. The challenge is therefore to develop and use alternative processing methods that have the flexibility of operation to cope with a wide variety of material types and tonnages, whilst providing high recoveries for valuable metals. Tetronics’ DC plasma smelting technology achieves industry-leading recovery rates for precious metals from a wide range of input materials and initial precious metal concentrations, whilst generating an inert slag-based material as a by-product (even when starting from a hazardous waste input material), approved within the EU for use in construction applications. This paper describes how this technology can be used as a key part of an overall process for the recovery of precious metals from these interesting materials.INTRODUCTION The extraction of gold from its ores by various forms of cyanide leaching has been practised by the mining industry for over a century (Minerals Council of Australia, 2005) and it remains the primary extraction method in a wide range of mining operations. The ability of cyanide to extract gold efficiently and quickly from lower grade ores without extensive additional processing, coupled with well-known methods to recycle the cyanide for re-use within the process mean it is often both the most economically preferable and environmentally acceptable method for recovering gold. As a result, 88% of all gold produced from mines in the USA in 2014 was recovered via leaching of open heaps or dumps (UGGS, 2016). Nevertheless, there are occasions where certain combinations of mineralogy and other circumstances reduce the effectiveness of cyanidation techniques, so that ever more elaborate additional processing steps are required, with inevitable increases in operating costs (Swash, 1988). In these circumstances, which are likely to be more common in future as ore qualities diminish, other methods of extraction may offer better alternatives. Whilst much less commonly used for Au extraction at present, pyrometallurgical methods are amongst the longest-established of these alternative approaches and merit serious consideration in such cases."

Jan 1, 2017

By R. O. Suzuki, S. Natsui, R. Nashimoto, T. Kumagai, T. Kikuchi, H. Takai

A newly developed computational fluid dynamics model based on a multi-phase particle simulation is presented for predicting the entrainment behavior of liquid metal into slag due to rising single bubble. By comparing results calculated using this model against experimental data, it was found that the transient behavior of bubbles and the two immiscible liquids can be accurately estimated by this method. The rupturing of the thin water film surrounding the bubble was less reliably predicted, but this 3-dimensional unsteady numerical model still nevertheless provides valuable new information for directly predicting the change in the liquid-liquid interface over time. This model predicted the Young-Laplace pressure, and the interface shape was simulated with volume conservation using this model as opposed to the conventional particle method. This simulation model can calculate both of dispersed phase and continuous phase seamlessly.

Jan 1, 2015

By M. Melashvili

"The SART Process was introduced to the gold mining industry in the late 1990s and several commercial plants were built over the following 10 to 15 years. Most of these plants have operated well and enjoyed plant performance in line with expectations based on the underlying chemistry of the process. However, two of the plants have consistently suffered from high reagent consumption and poor product quality, which has motivated a re-examination of the process fundamentals.The primary product in the SART Process is synthetic chalcocite, Cu2S, and the stoichiometric requirement for sulphide addition is therefore 0.5 moles per mole of copper in solution. It is shown here that when sulphide is added in excess of this amount (generally with the express purpose of lowering residual copper in solution) it not only fails in its intended purpose, but can have a negative impact on the settling and filtration characteristics of the copper sulphide product, as well as the final product quality. Moreover, these problems are exacerbated the higher the selected operating pH in the pH 3 to 5 range, and the longer the residence time of slurry in this pH range.Freshly precipitated copper sulphide compounds are known to be very fine and slimy, with poor settling and filtration characteristics. It is therefore important to engineer the SART Process in such a way as to encourage growth in the average particle size of the precipitate crystals. This was the rationale for recycling a portion of the thickener underflow to the primary reactor when the SART Process was developed. However, the theory of crystallization predicts that compounds of extremely low solubility, such as chalcocite (Cu2S: KSP = 10-48), are unlikely to experience growth in crystal particle size through heterogeneous nucleation and are more likely to grow through aggregation. On this basis, the SART practice of recycling a portion of thickener underflow to the primary reactor in the commercial plants is unlikely to lead to crystal growth via nucleation, and could in fact promote breakage of the aggregates that formed in the thickener. Recycling thickener underflow could therefore have the opposite of the desired outcome. The result of testwork that is reported here lends credence to this theory and questions the wisdom of recycling in the SART process."

Jan 1, 2016

By S. Kashani-Nejad

The kinetics of the thermal decomposition of samples of Mg2(OH)3Cl.2H2O that were obtained by a novel leaching technique applied to a commercial magnesium electrolysis feed were investigated under ambient atmosphere. Thermogravimetric (TG) Analysis showed that decomposition of Mg2(OH)3Cl.2H2O exhibited a single intermediate stage wherein crystalline water was lost at roughly 108 °C. Conversion of the resulting Mg2(OH)3Cl to MgO, HCl and 1120 occurred at temperatures above 398 °C. Thermal decomposition of anhydrous Mg2(OH)3Cl was seen to be consist of two stages. Both stages exhibit first order kinetics with respect to the weight percent of Mg2(OH)3Cl remaining in the sample. However, the rates of decomposition in the two stages were significantly different. Detailed analysis of the kinetic data suggested that the rate of decomposition of Mg2(OH)3C1 was controlled by the rate of removal of the gases released. The change in decomposition rate during the course of the experiments was explained by HCI being released in stage 1 and followed by release of H2O in stage 2.

Jan 1, 2004

By A. J. Paul Laprairie

The process for which it is to be used is too often the only consideration in the design of a vessel. A de-sign allowing for practical manufacture and erection, as well as for proper maintenance, can often give over-all economies. Most platework in-stalled today is of welded construction. Therefore, metallurgical control is important in its manufacture. Also, because many concentrating and re-fining processes tend to be corrosive, the subject of protective coatings as a part of the manufacturing process is extremely important. The plant de-signer should know how to evaluate and specify controls for the metallurgy and for the coatings. Mining operations are becoming more sophisticated in the field of mechanical engineering. More and more emphasis is being given to preventive maintenance. The first step in any maintenance program, however, is good inspection service. This paper will suggest methods for the inspection of platework, and outline methods for repair and replacement.

Jan 1, 1963

By G. Goodall, M. Muinonen, R. Pandher, R. Jabbar, S. J. Muinonen

"The implementation of a new and highly efficient converting practice at the Glencore Sudbury Integrated Nickel Operations Smelter has opened the possibility to further capacity increases by using larger ladles. To quantify the impact of increasing ladle sizes from 200 to 300 ft3, XPS constructed a detailed discrete event simulation using the commercial software package Rockwell Arena®. The challenges associated with implementing a model on an intricate and tightly scheduled process, and the solutions needed to derive meaningful results will be presented. The aisle capacity is predicted to increase by approximately 17 %, with a reduction in furnace tapping demand of 8 %. Arena modeling capabilities and the key factors contributing to the overall capacity increase at the Sudbury INO Smelter will be reviewed and presented.INTRODUCTION The Glencore Sudbury Integrated Nickel Operations (INO) comprises two Ni-Cu-PGM mines, Strathcona Mill, and the Sudbury Smelter. The Smelter has operated continuously since 1929 using different processes to produce nickel-copper Bessemer matte. Feeds to the Sudbury INO Smelter are a blend of concentrate from Strathcona Mill, Raglan concentrate produced at the mine-mill complex in Raglan, Quebec, as well as third party concentrate feeds shipped to Sudbury from around the world. In 2016, the Sudbury INO Smelter produced 75,900 tonnes of nickel and 20,000 tonnes of copper in Bessemer matte. The product matte is shipped to Glencore’s Nikkelverk refinery in Kristiansand, Norway where it is refined to produce nickel and copper cathode. A schematic of the Sudbury INO Smelter’s flowsheet is shown in Figure 1."

Jan 1, 2017

By D. C. Crothers

"What is new in air compressors? A good deal - the designers have been keeping pace with technical developments in related fields and also contributing new techniques of their own. Plant reliability no longer requires bulky slow-speed machines. Even the reciprocating machines, which still provide the most efficient method of compressing air, have been greatly reduced in size and installation cost for a given capacity rating. New materials and fabrication techniques are being used, by most manufacturers, to produce less costly plants in total. Many packaged plants are available, which generally means a more complete assembly for shipment. This type of construction offers savings in handling and erection costs at the site. A warning is in order, however - the extent of packaging in any given plant should be investigated carefully to determine what is included and just what field costs can be realized. A suggested specification has been offered for consideration when studying comparative costs. Rotating machines intrigue many because of their potential as regard fewer wearing parts, higher speeds and hence smaller units, utilizing less expensive drivers, and lack of contamination of the compressed air by lubricants. The inherent shortcomings of these machines - lower •efficiency and capacity control - have been much improved lately, and this type of plant is now becoming quite popular. Noise control, of much concern to everyone, is another development that has received considerable attention.Systems for efficient capacity control and continuous monitoring of compressor operation offer additional reliability and low-cost operation of the modern compressed air plant. Accessory equipment and its effect on over-all plant operation is also considered."

Jan 1, 1972

By Zhiqing Zhang, Changyun Chen, Qing Liu, Lin Lin, Zhihong Jia, Guangjie Huang, Lipeng Ding

The effect of interrupted quenching (IQ) treatments on natural aging and bake hardening response of Al-Mg-Si alloy was investigated by hardness measurements, tensile test, differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). The results show that interrupted quenching at 100oC could effectively suppress natural aging and improve bake hardening response. The optimized interrupted quenching treatment is 100oC for 45min, which gives the alloy a relatively low T4 temper strength and higher bake hardening response. The formation of highly dense cluster(2) during the interrupted quenching could be the reason for suppressing the natural aging and accelerating the precipitation of ß? phase during the paint bake treatment. In addition, interrupted quenching at higher temperature (170oC) results in unfavorable properties in both T4 temper and paint bake treatment. The formation of large precipitates is responsible for these undesired effects.

Jan 1, 2015