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By L Thompson, R C. West, T S. Kho

In 1978, the Outotec direct to blister flash (DBF) smelting process was commercialized with the commissioning of the Glogow 2 smelting facility in Poland. Since then four further DBF facilities have been constructed, two at Olympic Dam, one in Zambia and most recently one at Glogow 1 in Poland. The DBF smelting process differs considerably from conventional smelting process in both chemistry and unit operations, presenting opportunities for flowsheet capital and operating cost savings particularly when the concentrate copper grade is high. WorleyParsons has amassed considerable expertise in the Direct to Blister process and in this paper the process is compared to the modern two stage Double Flash process. The processes are modeled, and the key operating parameters, consumables and production metrics are directly compared. Subsequent flowsheets, key equipment lists and capital costs are also presented for comparison and discussion. The results show the range of concentrates which are most economically treated by the DBF process relative to those best treated in conventional processes along with those concentrates which could be treated by either process. INTRODUCTION The Outotec Direct to Blister (DBF) process was developed and installed at Glogow in 1978 (Czernecki et al., 2006). Currently there are a total of five DBFs built on three sites: Glogow No.2, Olympic Dam No.1, Olympic Dam No.2, KCM Zambia and Glogow No.1, being the most recently constructed. The DBF process was the first flash furnace process to produce blister copper and paved the way for the subsequent development of the flash converter and other continuous converting processes. Today four flash converters are in operation taking the total number of flash furnaces producing blister copper to eight. In all DBF operations it is the unique ore and concentrate composition which made selection of the DBF process the most attractive. In all cases, the concentrate is relatively high in copper but low in iron because chalcopyrite is not the major constituent. When considering smelting options for high copper, low iron concentrates a key question is then often asked, “At what point does it become economic to switch from two stage smelting and converting process to the DBF process?”

Jan 1, 2019

By R. Stauber, B. Friedrich, S. Hilgendorf, G. Homm, C. Gellermann

Due to recent regulations limiting tolerated lead concentrations in copper alloys, new recycling strategies have to be considered. This study investigates the suitability of technical approaches in order to recycle leaded copper alloys exemplified by CuZn39Pb2 and produce an alloy in compliance with future lead regulations in the European Union. Three pyrometallurgical methods are considered to achieve this goal, namely vacuum distillation, intermetallic precipitation and fractional crystallisation. The impact of essential process parameters i.e. pressure, temperature, time, atmosphere and quantity of additives are identified using thermochemical and kinetic modelling. An experimental implementation reveals a general suitability of all three refining processes. However, the individual efficiency of the different methods strongly differs. Thus, a detailed assessment is carried out in order to provide an evaluation on the efficiencies of these methods from a technological, economical and environmental point of view. Taking a possible industrial realisation into account, the authors recommend the approach of vacuum distillation, although the energy demanded is comparatively high due to the enthalpy of evaporation for zinc, or rather, lead. However, required lead concentrations can be reached quickly without introducing an external element to the material. The prediction of selectivity and evaporation speed, which are immanent variables for a successful implementation, can be validated experimentally. INTRODUCTION In 2016 approximately 1 million tonnes of leaded copper alloy semi-finished goods with an average lead content of 2.1 Ma% have been produced in the European Union (EU). The global production in the same period exceeded 5.5 million tonnes, while the lead concentration has stayed constant at around 2.4 Ma% for the last 50 years. Up to 80 % of the current production volume is covered with end-of-life scraps, which are used for direct re-melting, depending on the alloy composition. Lead has been a popular alloying element in copper alloys in general, and in particular in brass due to its positive impact on various mechanical, physical and chemical properties, especially machinability. Health and environmental concerns were drivers for many governments to implement limitations on lead. In order to further utilise the resource potential of leaded copper scrap, it is inevitable to develop methods to efficiently eliminate lead from circulation as far as possible. (Glöser, Soulier, & Tercero Espinoza, 2013; Soulier, Glöser-Chahoud, Goldmann & Tercero Espinoza, 2018)

Jan 1, 2019

By R. E. Whitehead

"Abstract - Biotite from aplite that appears to have crystallized simultaneously with disseminated Cu-Mo mineralization at MacLeod Lake in northern Quebec yields K-Ar dates in the range 2032 ± 44 Ma to 2097 ± 47 Ma. The mean value, 2065 Ma, is some 400 Ma younger than the 2485 ± 64 Ma date obtained from a hornblende concentrate separated from a granodiorite sill that is spatially, but apparently not genetically, associated with the disseminated Cu-Mo deposit. The mean biotite date of 2065 Ma at MacLeod Lake, a K-Ar date of 2055 Ma reported from an area 50 km east of MacLeod Lake and published dates of about 2000 Ma for galenas from the Chibougamau Cu-Au ores, suggest a widespread thermal and mineralization event, in that part of the Superior Province east of James Bay, that differs from the common late Archean mineralization that is related to volcanism and metamorphic-intrusive activity.Sommaire - Les datations au K-Ar sur des biotites qui auraient cristallise en même temps que la minéralisation disséminée en Cu et Mo dans une aplite mise en place au Lac MacLeod, au nord du Québec, s'échelonnent entre 2032 ± 44 Ma et 2097 ± 47 Ma. La datation moyenne, soit 2065 Ma, est d'environ 400 Ma plus récente que la datation obtenue pour un concentre de hornblende extrait d'un filon-couche de granodiorite qui est spatialement mais ne serait pas génétiquement associée à la minéralisation disséminée en Cu et Mo. La datation moyenne de la minéralisation au Lac MacLeod, soit 2065 Ma, la dataion au K-Ar à 2055 Ma citée pour une région à 50 km à l'est du Lac MacLeod, de même que les datations d'environ 2000 Ma établies pour des galènes qui se trouvent dans le minerai aurifère et cuprifère à Chibougamau, suggèrent un phénomène thermique répandu qui aurait produit la minéralisation dans cette région à l'est de la Baie James, dans la province du lac Supérieur. Ce phénomène serait diffèrent de celui qui aurait produit la minéralisation répandue d’âge archéen tardif qui elle serait associée à l’activité volcanique et à l‘activité intrusive accompagnée de métamorphisme."

Jan 1, 1992

By A. Majumdar, B. Servière, H. Persson

The CCR refinery, which was built in 1931, treats both internal and third party copper anodes to produce 325,000 mt of copper as cathodes. These anodes contain high levels of impurities, such as Ni, As, Sb and Bi, that reports to the electrolyte during the refining step and need to be removed in order to maintain cathode quality and operating efficiencies. In the purification plant, the electrolyte is de-copperized via electrowinning in three stages. In the last stage, the copper content of the electrolyte is reduced to below 1 gpl in order to maximize the co-deposition of As, Sb and Bi with the Cu. This is accomplished with minimum arsine gas generation by using periodic reversal of the current and by controlling the final copper content of the electrolyte. Nevertheless, the possibility of exposure to arsine is treated as a major risk and controls have been implemented to reduce this risk. This paper describes the controls in place at the purification plant, which are being continuously improved through periodic risk assessments and audits. INTRODUCTION The CCR Refinery, which is a part of Glencore Canada Corporation and located in Montreal-East, Quebec, is a custom copper and precious metal refinery, with a capacity to refine 325,000 tonnes of copper anodes per year. Copper anodes are received from the Horne smelter in Rouyn-Noranda, Quebec, Altonorte smelter in Chile and other 3rd party smelters. CCR anodes are produced using the spent anodes from the tankhouse along with purchased spent anodes and copper scrap. The precious metal plant treats the tankhouse anode slime, purchased anode slime, precious metal ingots and Doré anodes from Glencore’s Brunswick lead smelter in Belledune, New Brunswick. CCR products include copper cathodes, silver and gold bullion, a platinum-palladium concentrate, selenium, tellurium dioxide and nickel sulfate. In 1975 an accident occurred at CCR where two employees were exposed to fatal levels of arsine emitted from the then existing purification cells. This process was therefore shut down immediately. Research and development work was then initiated to determine the optimum electrowinning conditions whereby arsine gas generation would be minimized while maintaining high copper and impurity removal efficiencies. It was found that the application of periodic reversal of current (PRC) during the last stage of electrowinning retarded the onset of arsine formation while at the same time allowing the copper concentration to be reduced to less than 1 gpl (Houlachi & Claessens, 1978). A new purification plant was designed based on the PRC technology and was started up in 1976. In addition to the use of PRC electrowinning, the new plant is located in a fully enclosed section of the tankhouse. A special effort was made to design a ventilation system to evacuate the acid mist in addition to any arsine gas. Arsine monitors were installed to measure the emissions from the stack along with arsine levels in the workroom. The arsine monitors and the ventilation system were interlocked with the rectifiers (Thiriar et al., 1983).

Jan 1, 2019

By K Byrne, W. Hawker

The average grade of copper concentrate is steadily declining, forcing the industry to turn to lower grade and metallurgically challenging orebodies. When faced with a low grade, challenging ore, mining companies are often forced to choose between high recovery at low grade or low recovery at high grade. Hydrometallurgical processing of copper concentrates using metathesis reactions, which replace iron with copper in copper-iron sulphide minerals and increase the copper to sulphur ratio in copper sulphide minerals, provide an opportunity to upgrade copper concentrates and potentially allow high copper recovery for a high grade concentrate. Factors such as concentrate mineralogy, reaction time and temperature, and the concentrations of copper, chloride and acid in solution are reported to affect the reaction extent and mineral phases formed by metathesis. In this paper, a copper concentrate has been studied over a wide range of conditions to investigate the influence of these key parameters on the extent of copper metathesis reactions and product phases formed. Solution and solid phases are assayed with the main mineral phases identified by Quantitative X-Ray Diffraction. INTRODUCTION The minerals present in copper deposits determine the prospective processing options either: pyrometallurgical or hydrometallurgical. For copper oxide ores, copper is typically present as oxides, carbonate, chlorides, silicates and sulphates. These minerals are readily solubilised in acid and are usually treated through hydrometallurgical processes. The typical process route for copper oxides is to leach copper into aqueous solution, purify and upgrade the solution phase through solvent extraction and then recover copper as metal by electrowinning (Davenport, King, Schlesinger, & Biswas, 2002). Copper sulphide deposits may contain a multitude of copper bearing minerals, including chalcopyrite, bornite, enargite, covellite, digenite and chalcocite. The copper ore grade and treatment options are affected by the mineral type and distribution. Sulphide ores are typically treated through comminution and mineral flotation to form concentrates, followed by pyrometallurgical smelting. Hydrometallurgy can also be used to process sulphides depending on the mineralogy and impurity levels (Davenport et al., 2002). The trend of decreasing copper grade with increasing impurity levels are common across the mining industry and pose future challenges to copper processing. This trend has prompted research into hydrometallurgical options for upgrading copper concentrates. One promising hydrometallurgical option is using metathesis reactions. Metathesis reactions, sometimes also called double replacement or displacement reactions, are chemical processes involving the exchange of bonds between two chemical compounds or species. In this case, the metathesis reactions involve copper in solution exchanging with cations in the solid sulphide concentrate. The driving force for copper sulphide metathesis is the relative affinity of the exchanging cation elements for sulphide. Based on sulphide precipitation diagrams, the expected order of affinity for sulphide should be Hg2+ > Ag+ > Cu+ > Cu2+ > Bi3+ > Cd2+ > Pb2+ > Sn2+ > Zn2+ > Co2+ > Ni2+ > Fe2+ > Mn2+ (Monhemius, 1977). Hence, copper metathesis reactions are capable of increasing copper content and removing impurities such as iron, nickel, zinc and lead from copper concentrates.

Jan 1, 2019

By M. Pötsch, A. Kluckner, P. Söllner, W. Schubert

"The in situ block size is a key parameter in the geomechanical characterization of rock masses. It describes the fracturing of the rock mass and thus is a measure for the degradation of the rock mass strength. Several classification systems use the in situ block size. For instance, the Geological Strength Index (GSI) requires the “blockiness” and joint surface condition factor as key input parameters. The “blockiness” has recently been related to the in situ block volume (Cai et al., 2004). Due to the limited information about the internals of a rock mass, it is not possible to determine the in situ block size directly. Currently, the in situ block size is determined by calculations using oversimplified models, vague estimations or, due to the lack of relevant information, it is neglected. As remote measurement systems have become available for rock mass characterization, a more comprehensive record of discontinuities can take place. Measurements can be performed on exposed rock outcrops and in particular on tunnel faces and walls, delivering the location, orientation, spacing and persistence of discontinuities at an arbitrary number and locations. An estimation of the in situ block size at the same level of sophistication is still not available. This paper aims at examining the relationship between visible and measureable information at the rock surface, and the in situ block size. Three-dimensional block model simulations were performed using the block model engine of the distinct element code 3DEC. Initial investigations focussed on the minimally required observation area in order to obtain reliable block size distributions. Based on a representative volume element, a reference distribution of the block area at the observation area for a specific discontinuity system was determined. Subsequently, the size of the observation area was decreased stepwise and each new distribution was compared to the reference distribution. For all analyzed systems, it turned out that the mean block area must be smaller than 1% of the observation area to achieve a reliable block size distribution. Further simulations focussed on discontinuity systems with three non-persistent sets. The results were compared to the formula proposed by Cai et al. (2004). A transformation factor T was introduced which replaces the persistence terms in Cai et al.’s proposed formula. The factor describes the correlation between block volumes generated by persistent and corresponding non-persistent discontinuity sets. The simulations included the variation of the discontinuity set spacing, persistence, and orientation. The mean and additionally the 25%-, 50%- and 75%-quantiles of the block size distribution were analyzed. Examining all values for the transformation factor the distribution can be described by a power function with a negative exponent. The function depends on the persistence only. Finally, the results of random simulations were compared to the analytical formula using the transformation factor. The predicted mean and selected quantiles show a good agreement with the simulation results. It gives a comprehensive picture about the block size distribution in discontinuity systems with three non-persistent sets."

Jan 1, 2015

By Muhammad Usman Siddiqui

Managing and analysing the vast amounts of data collected in a mining project effectively is crucial for enhancing the project's economic feasibility. The efficient utilization of this data is critical to minimising the time spent on projects and increasing project value. Process engineers can effectively integrate geometallurgical data into plant operations by employing analytical tools like Python, significantly optimizing the mine-to-mill process. This practical approach is a game-changer in the mining industry. Classifying a geomet dataset into units of similar characteristics (properties of the ore) is an important outcome of a geomet study. This approach simplifies data classification, allowing for class-by-class process modelling, which improves the decision-making process in mine planning and development. Classifying a geomet dataset involves using grade, lithology, and test work data (if available) to create blocks of similar characteristics, known as ‘geomet units.’ Compared to conventional methodologies, these units provide context and empirical evidence that can be more accurately mapped onto block-by-block process flowsheet development and net present value (NPV) estimation. This robust classification method reduces a project's technical risks and influences the initial mine planning sequence to maximise profitability. Defining robust geomet units with data sets with similar material is challenging due to the vast amounts of data available and the database's high heterogeneity. The methodology's purpose is to minimise time-consuming low-value-adding aspects of geometallurgy. The approach is different for a greenfield and a brownfield study, as all the valuable data in a brownfield process can be utilised to define the geomet units. Python has various libraries providing multiple machine-learning algorithms to assist in classification. The k-means algorithm is used for clustering, and the SHapley Additive exPlanations (SHAP) method is used to quantify the effect of each feature on the clustering results. However, even with automation, the methodology still requires a keen eye to account for the nuances that appear from project to project.

Oct 1, 2024

By T. G. Joseph

The strain softening relationship developed in part 1 is now applied to coal. Having determined the post-failure stress-strain curve for coal specimens, this information can then be used in a finite element program, such as Phase 2, to examine the post failure characteristics of coal pillars. Using example data, the strength of coal pillars of different width/height ratios are estimated and compared with well-known empirical pillar size-strength relationships. In addition, the post-failure stress-strain behaviour of a coal pillar is compared with an empirical relationship reported in the literature.

May 1, 2002

By Jeremy P. Richards

Key inputs are volatiles and heat: Slab dehydration: Breakdown of amphibole and serpentine in hydrated oceanic crust releases fluids into mantle wedge, causing metasomatism.

May 1, 2008

By R. Liu

As Building Information Modeling (BIM) becomes widely adopted by the construction industry, it holds undeveloped possibilities for supporting Facility Management (FM). Some FM information systems on the market claim to address the needs for FM requirement. However, the question of whether the functionalities provided by the current BIM-based FM software companies are those actually required by the FM Professionals still need to be answered. The data is required by FM professionals in the operation and maintenance phases of facilities and type of maintainability problems that frequently occur, which can be solved early in design phase, have not yet been addressed. The aim of this paper is to clarify the frequently occurring maintainability problems and to investigate the potential areas that can use BIM technology to solve the maintenance problems in early the design phase. A survey was conducted to collect perspectives from the industry practitioners for the maintenance problems and their frequency. The survey results indicated that maintainability considerations should be taken into consideration during the facility design phase. The results also address the perceived areas by practitioners that need maintainability consideration in design phase.

Aug 1, 2013

Stope performance and geotechnical information at Xstrata Zinc George Fisher Lead-Zinc-Silver mining operations have been analysed in detail since the beginning in October 2003. This work has been included in a joint dilution study between Xstrata Zinc and the University of Saskatchewan. This paper presents an analysis of site geotechnical data and stope reconciliation that led to major changes in stope design, a reduction in dilution, and a significant increase in mining efficiencies. Detailed geotechnical data collection for a mine site or particular stoping area represents a large amount of information which is time consuming to review. However, it is this data that can make a significant difference in rock mass behaviour understanding. Simplification and averaging of conditions into zones of similarity, called structural domains, are common approaches for managing large amounts of data. There is a tendency to average rock mass properties to obtain inputs for numerical modelling and empirical design tools. This approach may be misleading if the inhomogeneity of the rock mass is contributing to the failure mode. This paper summarizes a novel approach for rock mass characterisation and stope design in a bedded sedimentary rock mass.

Apr 1, 2005

By R. C. Wallace

Since the time when Canada's East and West were joined by the railway, and communication was established into the interior, settlements grew on the southern fringe of the great Precambrian area that formed the northern protaxis of the continent during its vicissitudes of growth. They clung precariously to the fringe of that ancient land, for the Precambrian is not generous to those who wish to live by the fruits of the soil, except in those limited areas where the Pleistocene ice-sheet has been profuse in its gifts of clay to cover the hard surface of the Precambrian rock. Later settlements spread westwards over the expanse of Cretacean plains that now form the wheatfields of the Canadian West; but there still remained in northern and western Ontario, in eastern and northern Manitoba, a pioneer race, to whom agriculture had attractions only in so far that it provided the wherewithal to lay siege to the riches of the Precambrian. And they had a vision beyond their time. More than they knew, they had seized the fact that for the complete rounding out of Canadian national life, a8 well as for the establishing of the necessary contributions towards the economic stability of Canada and its provinces, an industry in mining sh01.dd be well and truly built in the hinterland of the central provinces. Failing the winning of mineral from the rocks, and timber from the forests, there would remain between the East and the West an enormous barrier of unproductive country which would not only be an incubus to the agricultural people in their struggle for economic liberty, but would effectively, and for all time, remain an un-populated void across which the aspirations of East and West would be unable to unite.

Jan 1, 1924

By M. Romana

"RMR geomechanics classification is being used all over the World as a useful tool for tunnel predesign and construction. Bieniawski (1989) provided guidelines for tunnel excavation and support, according RMR numerical values; guidelines which are now included in almost all tunnelling books, regulations, and Internet portals. But in the last 25 years tunnelling techniques have changed and some of the guidelines have become obsolete.. The conditions of tunnels for the 1989 guidelines application were: horseshoe shape; 10 m width; vertical stress < 25MPa; construction by drilling and blasting. Actually a substantial number of tunnels are mechanically excavated. The tunnel themselves are now bigger: a span of 14 m. is very common for transportation tunnels. The guidelines included the following concepts: excavation method, rock bolts (20 mm diameter, fully grouted), shotcrete, steel sets. There is an increasing gap between the 1989 guidelines and the practice: in many tunnels different to-the-case excavation and support requirements are established. Bieniawski himself has published a paper (Lowson & Bieniawski, 2013) with different guidelines based in Lowson’s practice, with no explanations and/or justification.In this paper a new set of RMR tunnelling guidelines is proposed taking account of the actual industry conditions, and increased safety regulations. The 5 classes’ limit RMR:values (80,60,40,20) are no more useful actually: Values of RMR (70, 50, 30) are used in practice to define quite different tunnelling techniques. Consequently a 10 subclasses system is proposed. Each subclass covers a span of 10 RMR points. As the number of mechanically excavated tunnels has increased a new correction factor is necessary, according the excavation method.The proposed 2014 RMR guidelines are for tunnels 10 to 14 meters wide, the world practice for new roads/railways tunnels. Many tunnels for water/ services are smaller with smaller support needs. Wider than 16 m caverns are out of the RMR system.It is not possible, nor desirable, to propose only a value for support in each subclass. The new guidelines propose an interval of values for certain types of support. More pessimistic values must be chosen for wider tunnels, tunnels with lower RMR values in each class and cases when a higher safety factor is asked for. More optimist ones are chosen for narrower tunnels, and higher RMR values. Some alternatives are almost complementary, others are contradictory. Sometimes several different techniques are proposed Guidelines are not automatic options. Good engineering judgment must be used when choosing between the different alternatives. Guidelines are not mandatory suggestions."

Jan 1, 2015

By M. Nowak

Extreme high grades often exert too much influence on surrounding block estimates, leading to a smearing of high grades that can cause overestimation of mineral resources. This concern underlies the decision to cap high grades, i.e., to lower the highest grades in a drill hole data set to some level deemed to be reasonable for producing reliable resource estimates. The choice of a capping level can, by itself, have a large influence on the analysis of the economic viability of a project. Despite this, it is often a choice that is made arbitrarily, guided more by art and tradition than by sound technical analysis. This paper makes suggestions for good capping practices, using methods and procedures that have been presented elsewhere, in the technical literature and in conference papers. The authors propose to use capping only if absolutely necessary, and review examples of cases where capping may not be necessary, or where capping does not make the estimates more reliable. It addresses two particular instances where capping is recommended: (1) where there is good reason to believe that estimation with uncapped grades will overstate the true underlying average grade, and (2) where there is potential for overly optimistic assessments of local block grades in the vicinity of some very high grade assays. The proposed capping practice is based on adjustments to only a very few high grade assays. The level of this capping can be assessed by bootstrapping and through analysis of the effect of extreme values on summary statistics like the average and the coefficient of variation. The paper recommends that good practice include an examination of the potential for local overestimation in higher grade areas.

Aug 1, 2013

By Tao Cheng

Previous research and applications in construction resource optimization have focused on tracking the location of material and equipment. There is a lack of studies on automated monitoring of the interaction between workers and equipment for safety purposes. This paper presents a new approach for measuring the safety performance of construction personnel particularly when they work in very close proximity to moving equipment as well as static hazards such as chemical and flammable substances. A method of generating hazardous zones according to the geometric and kinematic characteristics of the considered hazard is introduced. The spatio-temporal relationships between the hazardous zones and workers? positioning data collected by real-time location sensing technology are automatically analyzed. This approach has been validated in a controlled test bed environment that simulates a construction site. Results indicate that worker?s safety performance of selected activities can be automatically and reliably measured using the developed approach. Furthermore, a heat map is generated for visualizing proximity related issues in the test bed using the computed results.

Aug 1, 2013

By Jan E. Nesset, L. Paul Staples

"High Gradient Magnetic Separation (HGMS) technology, although developed over 2 decades ago, has not been widely applied to the separation of sulphide minerals. Under conditions of strong magnetic field gradients, weakly magnetic minerals such as chalcopyrite (CuFeS2) and marmatite (Zn(Fe)S, sphalerite with iron in solid solution) behave paramagnetically and can be effectively separated from diamagnetic minerals such as galena (PbS). The application of this technology to the separation of Cu-Pb and Zn-Pb bearing streams in the treatment of fine grained complex sulphides may in some cases be more effective than separation by flotation. A 2 TPH Sala HGMS pilot plant was operated at Brunswick for a nine month period, ending in March 1995. The testing demonstrated the mechanical reliability of the technology, the consistency of operating results and the scale up from laboratory testing. HGMS is seen as a complimentary technology to flotation, best suited to performing those separations of galena (and other diamagnetics) which flotation does not do as well.IntroductionBackgroundSince the turn of the century, the magnetic character or magnetic susceptibilities of minerals have been determined with increasing precision and accuracy. Figure 1 illustrates specific magnetic susceptibilities of some common minerals. As long as susceptibility ranges do not overlap, separation is possible.In 1937, the principle of using a magnetizable matrix material in a magnetic field to increase both magnetic flux density gradients and number of capture sites for susceptible minerals was first applied (Frantz). It was not until the 1970's, however, that the genuine development of wet high gradient magnetic separation began with the introduction of very fine matrix materials to the magnetized volume of large solenoid magnets. Today, dozens of HGMS units purify, filter and separate minerals, primarily for the removal of iron stained minerals from clays used in the paper coating and china clay industries and for the recovery of fine titanium and iron oxides in the iron ore industry. Only the Garpenburg mill in Sweden is currently applying a continuous HGMS machine to separate complex sulphide minerals; upgrading a lead concentrate since 1988."

Jan 1, 1996

By S. Eckert, M. Reuter, D. Obiso, S. Kriebitzsch, M. Akashi

The present paper focuses the application of CFD techniques to investigate the Top-Submerged- Lance (TSL) gas injection in liquid metal. Previous works of the authors have shown that up- and down- scaling procedures based on the modified Froude number have some shortcomings, as this approach does not take into account the interfacial and viscous forces. Indeed, surface tension and dynamic viscosity of the smelting slags (σ = 0.4-0.5 N/m, μ = 0.2 Pa·s) are higher than the operating fluids that have been used in literature (water, paraffin oil) to study TSL injection in down-scaled furnaces. In order to get closer to real systems, the authors study the TSL injection of Argon in a liquid metal. An experimental campaign was carried out in the X-ray lab at Helmholtz-Zentrum Dresden-Rossendorf (HZDR), where the eutectic alloy GaInSn was used as liquid phase. The alloy is liquid at room temperature, and X-Ray imaging is used to picture the multiphase flow in a quasi-2D vessel. The aim of the present work is to demonstrate the applicability of CFD techniques to model multiphase flows involving liquid metals, and validate the model using the data produced at HZDR. The commercial software ANSYS Fluent® was used together with the Volume of Fluid model to directly resolve the gas-liquid interphase. Some features of the flow, such as the void fraction distribution and bubble detachment frequency are tracked with CFD and compared to the experimental data. INTRODUCTION In the last thirty years the TSL smelting technology has increasingly been used for industrial non- ferrous smelting processes and is now one of the significant pyrometallurgical processes. Developed in the early 1970’s at CSIRO, the furnace is nowadays commercialized in different market sectors, including copper and lead smelting, zinc fuming, waste treatment and slag recovery (Floyd, 2005). Despite the wide application of these reactors in the pyrometallurgical market, some aspects of the process are still not fully clarified, since in-situ measurements and optical accesses are prohibitive because of the high temperatures and aggressive conditions. Phenomena such as the bubbling regime, the slag solidification and the submerged combustion still need a deeper scientific investigation to obtain a better understanding of the process.

Jan 1, 2019

By C. Allen, M. Gangal, J. Stachulak

"Most underground diesel equipment is equipped with diesel oxidization catalysts (DOCs) to reduce carbon monoxide and hydrocarbon emissions. DOCs do not alter nitrogen oxides concentrations but can promote the oxidization of nitric oxide (NO) to the more toxic nitrogen dioxide (NO2). Vale and CanmetMINING have been researching how to reduce worker exposure to diesel emissions by testing mining equipment DOCs. Results indicate a > 77% decrease in carbon monoxide concentration but a 46–315% increase in NO2 concentration for 8-mode test cycles. It is recommended that DOCs that increase NO2 emissions be evaluated regarding their continued use in underground operations.RÉSUMÉ La plupart des équipements miniers souterrains sont équipés de catalyseurs d’oxydation diesel (DOC) afin de réduire les émissions de monoxyde de carbone et d’hydrocarbures. Les DOC ne modifient pas les concentrations des oxydes d’azote mais ils peuvent faciliter l’oxydation du monoxide d’azote (NO) en dioxyde d’azote (NO2), plus toxique. Vale et CanmetMINING effectuent des recherches pour réduire l’exposition des travailleurs aux émissions de diesel en analysant les DOC des équipements miniers. Selon les résultats, une diminution > 77 % dans la concentration de monoxyde de carbone est atteinte mais elle est accompagnée d’une augmentation de 46 à 315 % de la concentration en NO2 pour des cycles d’essais à 8 modes. Il est recommandé d’évaluer les DOC qui augmentent les émissions de NO2 pour décider de la poursuite de leur utilisation dans les opérations souterraines."

Jan 1, 2016

By Bruce Chalmers

INTRODUCTION TIE most important practical problem with which Physical Metallurgy is faced is the control of the mechanical properties of alloys. The most difficult aspect of this problem is the development of new alloys with the properties that are required for meeting exacting engineering requirements. A great measure of success has been achieved by following the empirical method and most, if not all, of the present variety of alloys have been developed by the process of experiment and observation or trial and error. It may, however, be that this method will become. less productive as time goes on, and that eventually it should be replaced by a process based on an understanding of the factors that determine the properties, so that alloys can be &apos;designed&apos; to meet the requirements. This method of investigation will not be possible until a much better fundamental understanding of metals has been gained, and this will come only about as a result of a great deal of detailed research. The subject of Physical Metallurgy can be divided, as follows, into two parts: we may consider the factors which determine the structure, in the broadest sense, of an alloy. These include the composition and also the treatment to which the material has been subjected. The second aspect is the influence of the structure on the mechanical and other properties. In order to make an effective contribution in this field, it is necessary for an individual or a group to concentrate on a specific and very restricted topic. It is proposed to discuss in some detail the particular subject in which the writer and his colleagues are working.

Jan 1, 1951

By D. Royston

In SAG mills fed with a variety of ore types, hard packing between the shell lifters can come and go depending on rock type and rock size distribution and the presence of a binder. Packing can appear in all sizes of SAG mills, and can be tenacious. High ball impact forces (depending on ball size) in larger mills may compact and encourage packing. Packing can have a negative impact on milling performance and a change in shell liner design may be required to remove it. However shell liner design changes need to be managed with care to ensure liner reliability. In smaller mills control of packing can extend shell plate wear-life and may help to maintain milling performance in fixed-speed mills through the liner wear-cycle.

Jan 1, 2012