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By Richard W. Hutchinson, Christopher Osterman

Abstract -The Selebi-Phikwe deposits are hosted by amphibolite to granulite facies gneisses of the Limpopo belt. The sulfide orebodies are generally stratiform and conformable to the foliation of the wallrock gneiss. Sulfide remobilization has occurred during metamorphism and has produced discordant sulfide veins, called piercement structures, which project into the hanging wall and foot­ wall gneisses. These piercement structures are compositionally similar to the stratiform sulfides, consisting mainly of pyrrhotite, pentlandite and chalcopyrite. However, texturally the piercement sulfides are coarse grained and inclusion-free, whereas the stratiform sulfides are fine grained and packed with tectonically produced wallrock inclusions. The piercement structure sulfides and adjacent stratabound sulfides were sampled and analyzed for major base metals and PGE's for comparative purposes. Most of the piercement structures were enriched in Cu, Ag and Au, whereas they were generally depleted in Ni, Co, Fe and PGE's. Changing elemental associations were observed from the stratabound sulfides and along the length of the piercement structures. This and the degree of depletion or enrichment of various major and minor elements in the sulfide piercement structures may reflect the relative mobilities of metals under metamorphic conditions. The similarities between sulfide piercement structures and the footwall Cu-POE veins in some Sudbury deposits are reviewed.

Jan 1, 1994

By G. Velarde

Agglomeration has as main objective to form a uniform and highly permeable heap for leaching. An inaccurate dosage of moisture during agglomeration leads directly to poor agglomerate quality and segregation of particle sizes during stacking. This causes a heterogeneous distribution of the leach solution inside the heap which invisibly and practically permanently affects the recovery. Unfortunately, only when this becomes serious and the mineral contains an excess amount of fine particles and/or clays then the poor permeability of the pile becomes obvious. This paper is based on the experience of Minera Cerro Verde in the development and application of a quantitative method to control moisture during agglomeration. As the amount of fine particles/clays varies, the quantity of moisture has to be altered in real time. The measurement of agglomerate electrical conductivity is used for it. This concept is based on the sharp change seen in conductivity when the mineral passes its absorption limit. A liquid conductive film then begins to form over the surface of the particles, which leads to the formation of agglomerates through liquid bridges, which are also electrical bridges. Moisture is adjusted to reproduce a value of conductivity established previously and is the guiding parameter. Moreover, moisture amount added to reach this conductivity parameter provides information about the fines/clays relative content for best leaching management.

Jan 1, 2004

By J. E. Nesset, L. S. Urbanoski, J. R. Goode

"The benefits and advantages of pre-competitive, collaborative industry/university research are not always well appreciated. This paper presents the case study of a current collaborative project between CAMIRO-Metallurgical Processing Division and McGill University that is investigating the understanding and prevention of sphalerite activation in lead and copper-lead flotation circuits. The benefits of the research findings to the sponsors can be maximized by an approach which links the researchers themselves with the sponsors at frequent, interactive project review sessions. Some examples of the findings and their application to industry are also presented along with a general update on CAMIRO-MPD.INTRODUCTIONThe history of Canadian efforts in the area of collaborative pre-competitive research is not long when compared to Australia (AMIRA) and Britain (MIRO). AMIRA (Australian Mineral Industry Research Association) began over 40 years ago and has had a well recognized role in bringing together industrial sponsors and researchers to fund a large variety of very significant development projects in that country, The total AMIRA funding effort for mineral processing work currently exceeds some $Aus 40 million with new projects valued at about $Aus 12 million initiated each year. This high level of commitment by industry has contributed to establishing Australian researchers and their facilities as among the best in the world.Canadian companies have traditionally funded much of their R & D in-house with extensive facilities and large funding commitments. The past 2 decades have seen most of these facilities disappear. The current situation is one in which only the largest integrated metal and mining companies have retained their own R & D groups (e.g. INCO, Falconbridge, Noranda). Industry-funded research at universities was primarily through individual efforts by the mining companies and rarely included collaboration with other mining companies, equipment or chemical suppliers, or engineering firms."

Jan 1, 2001

By Lloyd W. Trevoy

Syncrude Canada Limited is presently studying commercial production of heavy minerals from plant tailings of the openpit A lhabasca tar sands operation. When tar sands are processed and upgraded to synthetic crude oil, heavy minerals can be removed f rom the extraction circuit and beneficiated to provide concentrates of zircon and titanium minerals. Calculated recovery rates indicate that crude oil production capabilities of 105,000 barrels per day would provide 26,000 tonnes of zircon and 114,000 tonnes of titanium minerals annually. The titanium minerals concentrate is a mixture of ilmenite, leucoxene and rutile; it could be used as recovered or upgraded to synthetic rutile. With the consrruction of further synthetic crude oil plants in Western Canada, a large reserve of heavy minerals will become available.

Jan 1, 1984

By T. Plikas, T. Porretta, M. Al-Dojayli, B. Pretorius, J. Woloshyn, H. Ghorbani

"Water-cooled ducts represent an integral part of high temperature off-gas systems in metallurgical processes. Typically, off-gas enters these ducts at significantly elevated temperatures; therefore, water cooling may be required to maintain the duct skin temperature within allowable design limits. These off-gases are typically of high mineral content that could lead to dust buildup, and there is a possibility of slag buildup / molten metal splashing. Therefore, dust cleaning provisions may be necessary in order to remove or minimize accretion on the duct wall, which could otherwise impact the water cooling and the system process efficiency. These ducts may have complex geometry and experience a wide range of loading, including gravity loads, water and gas pressures, cyclic thermal loading and dynamic impact forces. Consequently, the thermo-mechanical assessment of such water-cooled ducts is critical and requires consideration phenomena such as high temperature gradients, potential nucleate boiling, thermal ratcheting and fatigue failures. Such assessment is not comprehensively covered by design-by-rule design codes and guidelines due to its complexity. This paper presents a successful implementation example of design-by-analysis methodology to improve the design and extend the life of a water-cooled furnace transition duct using Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA).INTRODUCTION Water-cooling represents an important part of high temperature off-gas systems in metallurgical processes. Typical temperatures of the off-gas in the furnace uptake are in excess of 1400°C, and thus there is a need to maintain the water-cooled duct and jacket skin temperatures within their material allowable design limits. Water-cooled channels have been used effectively in arc furnace roof design (Sosonkin et al., 1972; Smolyarenko and Khainson, 1988) and other furnaces as well as in furnace fuming jackets (Scholey et al., 1994). The design of these systems was based on one-dimensional analysis to ensure sufficient cooling is available under extreme furnace conditions (Smolyarenko and Khainson, 1988; Scholey et al., 1994). With advancement in furnace and fuming system designs, water-cooled duct designs have become more complicated in geometry. Numerical techniques, such as three-dimensional fluid flow and heat transfer modeling, are therefore needed to more accurately calculate water velocity, temperature and convective heat transfer coefficients in the water-cooled channels (Haywood et al., 2002; Henning et al., 2010). This is of particular importance around geometric corners where stagnant water flow may lead to local nucleate boiling at the critical heat flux, causing hot spots (Bergman et al., 2011). High wall skin temperatures increase the risk of failures due to thermal stresses as well as increasing corrosion rates (Gelfi et al., 2012), leading to costly equipment downtime and potential safety risks."

Jan 1, 2017

By Jennifer Abols

In July of 2013, Lundin Mining acquired the 2,000 tpd Eagle nickel and copper project from Rio Tinto. The project had been put on hold earlier in the year and construction was approximately 50% complete. Lundin immediately accelerated project activities and by September of 2014 the project was constructed, commissioned and ramping up. The newly commissioned facilities went on to reach design throughput, recovery and product quality targets by the end of the year. This was accomplished ahead of schedule and below budget despite numerous obstacles including the worst winter on record in the past 50 years for the area. What led to the success of the project, and in particular the commissioning phase of the project? This paper takes a high level look back and provides an overview of the methodology used, key issues encountered and lessons learned to answer this question.

Jan 1, 2015

By A. P. Page, G. E. Alexander, L. L. Sirois, A. A. Winer

A knowledge of the electrical surface characteristics of minerals is all-important in the choice of treatments to up-grade and beneficiate them. At their solid-liquid contacts, there are transfers of ionic species, which for insoluble oxide minerals are the H+ and OH-ions. The adsorption density of these ions can be detected by carrying out potentiometric titrations, and this paper describes the automation of such an apparatus. The details are discussed fully and the validity of the method is demonstrated by flotation tests.

Jan 1, 1969

By Randy Settgast, Daniel Moos, Hyunil Jo, Ghazal Izadi, Christine Baba

"Analyses of production logs of multiply fractured horizontal wells in unconventional plays show that only a small percent (~30%) of perforation clusters contribute to production. We present in this paper one possible approach to mitigating this problem, based on use of a fully 3-D numerical model of fracture propagation through a heterogeneous medium, by studying the influence both of spacing and of perforation friction on the initiation and propagation of simultaneous hydraulic fractures from a horizontal wellbore. The results indicate that while limited-entry perforating can help to equalize the lengths of fractures simultaneously growing from multiple clusters, it cannot equalize their widths. Both fracture width and fracture length can be equilibrated by combining non-even cluster spacing with limited-entry perforating. This has obvious benefits as it allows equalized placement of proppant across the entire series of perforation clusters, resulting in similar fracture widths and conductivities which enhances the likelihood that all clusters will contribute equally to production.INTRODUCTIONThere is substantial evidence from production logs and other information that during the hydraulic stimulation of horizontal wells, not all perforation clusters within a given stage will produce. One possible cause is the interaction between the hydraulic fractures emanating from each perforation cluster. Typically fractures created at the outer perforation clusters create “stress shadows”, i.e. increases in compressive stress in the minimum principal stress direction, which limit the growth of fractures growing from interior clusters; this is confirmed by modelling [1, 2, 3]. An example of this can be seen in Figure 1 which shows the final configuration of simultaneously propagating fractures from multiple, evenly spaced clusters when there is no perforation friction. The inner fractures are substantially shorter, reproducing the results by Bunger and Peirce [3]. The inner fractures also have substantially smaller widths.One approach to equalize the growth of simultaneously propagating fractures from a horizontal wellbore is by using limited-entry perforating as a method to equilibrate the flow rates into each of the different perforation clusters. Perforation friction is caused by the finite diameter of the entry points into the formation, and leads to a pressure drop across each perforation which is proportional to the flow rate squared. Fractures that take more fluid have a higher fluid velocity through the perforations than fractures receiving less fluid. This causes a larger pressure drop between the wellbore and more rapidly growing fractures, compared to the same pressure drop between the wellbore and the fractures that grow more slowly. Because pressure within the wellbore is approximately the same at each entry point, the larger pressure drop leads to less pressure being delivered to rapidly growing fractures, thereby decreasing their ability to propagate and reducing the amount of fluid they are able to receive. Because the mass rate of injection into the wellbore is constant, this forces more fluid into the fractures that were propagating more slowly, increasing their growth rate. It also increases the pressure required to drive fluid injection. The balance of these effects makes the system largely self-regulating and delivers more balanced fracture growth. While this effect is well known, it is often neglected in current numerical models."

Jan 1, 2015

By H. A. ?ye

The ISO TC 226 (Materials for the production of primary aluminium) has presently issued more than one hundred standards on the materials: alumina, pitch, petroleum coke, carbon anodes, carbon cathodes, ramming paste, fluorides and refractory). The object of the standardization work is to find methods that both material producers and smelters will accept. Methods that are specific for the operational conditions have been developed in addition to more traditional room temperature methods. Examples of important properties under operational conditions are: Air and C02 reactivity of anodes, Equivalent temperature for baked anodes, Sodium expansion of cathode blocks, Shrinkage and Rammability of paste, Penetration of electrolyte into refractories.

Jan 1, 2006

By Andrea M. Ouchi

A major focus of ground control research presently being conducted by the Geomechanics Group in the University of British Columbia Mining Engineering Department is to incorporate weak rock masses (RMR76 less than 50) into existing empirical design relationships. An emphasis is being placed upon the updated span design curve/critical span graph originally developed at UBC. The original database has been augmented by mapping of one mine in Montana and of several mines within the Carlin and Getchell Trends of Nevada. In addition, a neural network analysis has been performed and modifications of the span design curves at the lower RMR76 range have been made. The common factor in all the above mentioned mines is a weak back and/or walls. In most cases, the ore zone is the weakest rock unit and must be dealt with to safely extract the mineral bearing rock. This work attempts to provide rock mechanic tools that will enable a mine operator to make economic decisions that will also ensure a safe working environment.

May 1, 2004

By W. G. Worcester

Generally speaking, the term 'clay' appears to convey but little to the average layman other than of a sticky substance to be rigidly avoided when making a cross-country drive in the family ark- especially so if the chains have been left behind. On the other hand, the technical ceramic; engineer, though his chariot be bogged in the self-same mud-holes, will, more than likely, be planning on ways and means for the conversion of the troublesome gumbo into paving bricks over which all might ride with pleasure and security. However, to come to the point, the term 'clay' bears much the same relation to the ceramic world that the term 'ore' does to the metallurgical; in other words, as there are many kinds of ores, so also are there many kinds of clays, and it therefore becomes necessary to classify and sub-classify them previous to a discussion of their relative values and importance. Hence, a brief digression will be made from the main topic of this paper in order to enumerate and classify a number of the more important types of clays. By so doing, the relative position of Saskatchewan clays, later discussed, will be better understood.

Jan 1, 1929

By Real Daigneault, François Robert, J. Paul Golightly, Jean-Yves Cloutier, Jayanta Guha, Pierre Pilote

"The Casa-Berardi East, Center and West deposits, located in the Archean Abitibi, Sub province, are hosted by volcanic and sedimentary units of varying compositions, less than300 m from the Casa-Berardi fault (CBF). The CBF, a brittle structure, represents an increment in the structural evolution of a regional-scale deformation zone showing ductile-brittle behavior known as the Casa-Berardi deformation zone (CBDZ). The CBDZ is characterized by a mylonitic Sc1 foliation which is folded a.n4 deformed by a later sczfoliation in high strain zones.Four generations of quartz vein and fracture systems have been recognized within the Casa-Berardi deposits. Most economic gold mineralization, occurring in the second generation system, is found within high strain zones. This system hosts three types of mineralized structures: (1) banded quartz veins; (2) swarms of veins and mineralized host rocks; and (3) disseminated sulphides along fractures. An early carbonate hydrothermal alteration zone (pre- to syntectonic) surrounds the deposits. Alteration associated with gold mineralization is contemporaneous to late ( syn- to post-tectonic) relative to the development of progressive deformation in the CBDZ. The geological characteristics and paragenesis of the four quartz vein and fracture systems developed as an integral part of the geodynamic evolution of the Casa-Berardi deformation zone."

Jan 1, 1990

By James L. Parks, David M. Kjos

"Significant increases in mill liner life and plant availability can be achieved by following guidelines that have evolved from over twenty years of practical experience with autogenous grinding (A0) and semi-autogenous grinding (SA0) mills. A0 and SA0 mill liner functions, performance criteria, designs, wear-resistant materials and maintenance procedures are reviewed. Operating practices that can lead to accelerated wear and breakage are discussed.IntroductionEfforts to improve the performance of liners for autogenous grinding (AG) and semi-autogenous grinding (SAG) mills began as soon as the modern, large-diameter versions of these comminution machines were first intalled in commercial plants twenty years ago . While concentrators with conventional circuits were typically running at 95010 or better mill availability, many of the new autogenous and semi-autogenous circuits were struggling to achieve 80% availability. Liner maintenance, which involves not only material and labour costs but also loss of production, was quickly identified as one of the major reasons for downtime.Today, liner designs and materials have evolved to the point where virtually maintenance-free liner life of two to three years is possible in autogenous mills and one year in the more severe operating conditions encountered in semi-autogenous mills. Of concern, however, is that hard-won lessons from the past sometimes seem to be forgotten or ignored during the design of new mills and the operation of existing mills. As liner suppliers, we are often confronted with performance problems that could have been avoided by applying well-publicized guidelines for liner design and materials selection.This paper provides an overview of AG and SAG mill liner functions, criteria for evaluating performance, designs, wear-resistant materials and maintenance procedures. Also, operating conditions that can lead to accelerated wear and liner breakage are discussed in detail."

Jan 1, 1990

By J. C. O'Rourke

"Gibraltar Mines Ltd. has been operating its open pit copper mine for fifteen years. In that time over 140 million tons of waste and low grade material has been placed on the mine waste dumps. Laboratory and in-situ testing indicated that enough leachable copper was recoverable from the dumps to justify a leaching operation which would include the construction of a solvent extraction-electrowinning plant. The plant, which was commissioned in October, 1984 was designed to process 3,000 usgpm of dilute copper solution to produce 5,000 tons per year of high quality cathode copper.This paper deals with the start up and initial year of operation of Gibraltar's SX-EW plant. The three areas: leaching solvent extraction and electrowinning are presented with emphasis on the innovations which were made to help overcome the problems unique to die Gibraltar operation.THE LEACHING CIRCUITThe mines waste dumps are leached to produce a pregnant copper solution as feed to the SX-EW plant. To achieve this the dumps are sprinkled with a mildly acidic solution which percolates through the dump. In travelling through the dumps the solution contacts the surfaces of the liberated copper minerals and disolves the soluble copper into the form of copper sulphate. The leaching reaction is achieved by a combination of bacterial action to oxidize the suphides and solublization of the copper into the acid solution.For the bacterial action to occur the dumps must be at or near the ideal pH of 1.9 - 2.1 and the necessary elements of the reaction must be present. Because a bacterial reaction is involved there is a lag time between the time when the conditions for bacterial growth are achieved and when the bacteria are in their active growth phase. Laboratory tests with Gibraltar ore indicated that bacterial action takes two to three months to reach its maximum rate. See figure 1.The expected lag time for the planned rate of bacterial leaching prompted Gibraltar to start irrigating the dumps in late June 1986 for a plant start up in early fall. The lag time proved to be longer than expected and the dumps took until November to start producing copper at the expected rate. See figure 2."

Jan 1, 1988

By W. L. Murphy

The Star Lake property, located 115 km northeast of La Ronge, Saskatchewan is underlain by metamorphosed andesitic tuffs and flows which have been intruded by the dioritic to granitic Star Lake Pluton. Gold mineralization on the Star Lake property was first discovered at Ru h Lake by E. Beveridge in 1959 and by M. and E. Hird in 1961. In 1960 E. Partridge discovered Kahn 18 and Kahn 28. In 1982 the SMDC-Starrex joint venture completed geophysical and geochemical urveys including magnetics, VLF, IP/Resistivity, vegetation, bulk till and oil sampling, followed by drill testing of pecific targets. To date the most ignificant depo it is the 21 Zone which contain drill indicated reserves of 230,000 tons grading 0.5 oz/ton Au . The 21 Zone con ists of quartz with 5-10% (locally > 30%) drusy pyrite, minor chalcopyrite and trace amounts of scheelite, chalcocite and arsenopyrite. The 21 Zone is enclosed by a 25-50 m wide band of mylonitized monzonite. The mylonite occurs in the central portion of a 300 m wide northeasterly trending zone of brittle deformation .

Jan 1, 1986

By B. S. Ignasiak, Dennis Carson

"Laboratory study of the behaviour• of binary coal blends shows that coke strength is more closely dependent on the distribution of ""reactive"" oxygen in the parent coals than on their proximate, elemental or petrographic compositions, and it also appears possible to qualitatively predict coke strength from information about reactive oxygen. Proceeding from this recognition, experiments were carried out to test the possibility of preparing metallurgical cokes from binary blends in which non-caking hvb coal was substantially freed of reactive oxygen by prior heat t1•eatment under controlled conditions. The results indicate that such blends can yield surprisingly strong cokes and that coke strength may be amenable to further improvements by modifying the size distribution of the pre-heated component and the rate at which it is charred."

Jan 1, 1976

By Timothy W. Ellis, Abbas H. Mirza, R. David Prengaman

Recycled lead, i.e. material produced by the recycling of lead-acid batteries, has become the primary source of lead in much of the world. This has been important to the recycled lead industry as other uses have dwindled, e.g. lead based pigments, chemicals, fuel additives, solders and CRT glasses. Presently, battery manufacturing accounts for greater than 85% of lead consumption worldwide while recycled lead accounts for approximately the same market share of lead supply. Battery manufacturing and production of recycled lead are intimately coupled. In 2007, of all the industrial base metals, lead from lead-acid batteries had the highest recycling rate in North America at greater than 95%. In this paper we will review some of the processes and technologies used in a modern lead acid battery recycling facility, and how recycled lead has become the material of choice for battery construction through the development of a recovery and refining process that exceeds the industry requirements. We will also briefly review an advanced air emissions treatment system in a modern lead recycling plant that demonstrates the feasibility of a new maximum available control technology (MACT) for secondary lead smelters.

Jan 1, 2011

By Yu Chen, Charlie C. Li

The application of rock bolts for the stabilisation of underground openings needs a good understanding of the response of the bolts during rock excavation. The pull-and-shear performance of two types of rock bolts—that is, the fully encapsulated rebar and the D-Bolt—has been studied both experimentally and numerically. The rock bolts were tested under a pull-and-shear load at five displacing angles (i.e., 0°, 20°, 40°, 60°, and 90°), and at the same time, the strains on the bolts were monitored during testing. The two types of rock bolts have similar loading capacities, while the loading angle has obvious influence on the deformation capacity of the D-Bolt. The ultimate total displacement of the D-Bolt decreases from 140 mm under pure pull loading to 70 mm under shearing. The displacement capacity of the rebar is not significantly influenced by the loading angle but remains at a quite low level from 29 to 53 mm. The D-Bolt yielded in a longer section the rebar bolt under pure shear. A trilinear material model was used to simulate the strain hardening behaviour of the bolt steels in the numerical code FLAC3D. The numerical results show that the axial load in the bolt decreases exponentially with the distance from the loading position for the rebar bolts, but it remains constant in the bolt sections between the anchor positions for the D-Bolts. When the bolt is subjected to a lateral load, shear stresses are created on the D-Bolt surface within a short distance from the loading position.

Jan 1, 2015

By A. R. Farkoosh, J-P. Fortin, M. Pekguleryuz, S. Bagherpour

"Titanium aluminides are structural intermetallics which offer an attractive combination of high temperature strength and light weight. For such properties, these intermetallic alloys have become front-runners in replacing nickel-based superalloys used for several high temperature applications. These alloys are produced from metallic titanium, aluminum and master alloys involving an expensive and difficult process. A low cost alternative to current industrial production method is the new modified aluminothermic process which directly reduces titanium oxide (TiO2) to titanium aluminides. Nevertheless, this process has itself significant challenges in achieving alloys free of oxide inclusions; the close densities of the slag and the titanium aluminides makes slag/molten metal separation a challenging task. Usually, the alloy produced requires a second refining step. In this study, thermodynamic calculations based on CALPHAD method were performed to determine the solidification path and an attempt has been made to develop a criterion to increase the density deference between the slag and the alloy by alloying with appropriate elements. Furthermore, scanning electron microscopy (SEM) and x-ray diffraction (XRD) techniques were utilized to examine the microstructure and phase selection of three Ti-Al alloys produced by the aluminothermic reaction, including the as-cast, refined in a controlled atmosphere and inert-gas-refined alloys. The composition range of the alloys studied was restricted to the a2-Ti3Al + ?-TiAl phase field (Ti-30Al) in the binary Ti-Al phase diagram leading to a lamellar structure with different complex intermetallics as shown in Figure 1.INTRODUCTIONTiAl based alloys are promising structural materials for high temperature aerospace and automotive applications. This is due to some attractive properties such as low density, high specific strength, high specific stiffness and high temperature strength retention (Wen-bin, Xue-wen, Hong-fei, & Yong-feng, 2011). These alloys have become leading candidates to replace Ni-based super alloys in gas turbine engines. Replacement of Ni-based super alloy parts with titanium aluminides is expected to reduce the structural weight of high performance gas turbine engines by as much as 20–30% (Kothari, Radhakrishnan, Sudarshan, & Wereley, 2012)."

Jan 1, 2016

By A. R. Sorta, D. C. Sego

ABSTRACT The settling, shear strength, and index properties of oil sands fines-sand mixture tailings (FSMT) for a wide range of solids and fines content are investigated. Results indicate that the liquid limit of FSMT obeys a linear mixture law. The fines-water ratio (FWR) governs the permeability of composite tailings (CT) and CT with comparable geotechnical behaviour can be produced from the same initial FWR mixtures. A phosphogypsum (PG) dosage > 900 mg/kg does not improve the dewatering behaviour of CT. The undrained shear strength of FSMT at the liquid limit is approximately 2.4 kPa, but is dependent on fines content at the plastic limit.

Jan 1, 2013