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On the 26th of June 2000 a hydraulic fill retaining barricade failed at the Bronzewing mine in Western Australia. The barricade failure resulted in the release of 19,000 m3 of saturated hydraulic fill into the mine and caused the deaths of three miners. Following this tragic accident, the practices and procedures of mines using hydraulic fills came under intense scrutiny by regulatory bodies and mining companies. At this time, the use of hydraulic fill at Normandy?s zinc/copper Scuddles mine was suspended and waste rock became the sole backfill material in use underground. By 2003, development of the adjacent Gossan Hill mine had progressed to a point where a self supporting fill material was required to enable full recovery of high grade ore. Cemented hydraulic fill (CHF) was identified as the optimal fill type and work began on designing appropriate management procedures and controls to ensure the safe implementation. This work included definition of the fill properties, plant design and construction, reticulation system design, design of stope barricades and drainage systems and fill placement control and monitoring practices. CHF placement began on 16th July 2004 and has continued to date. Significant operational experience has since been gained in areas including plant performance, fill product quality assurance, barricade construction, stope drainage and in-situ performance.

May 1, 2007

By S. Junnikkala, K. Föhr

"Experiments were performed with plant feeds with a continuous 1,8 m3 cell at Pyhasalmi mine with Cu flotation feed in order to test the applicability of the bubble surface area flux as an indicator of the flotation rate constant. It was found that bubble surface area flux could not predict the rate constants of coarse Cu containing fractions. In the middle size fraction, the correlation coefficient in the rate coefficient estimation was higher but not statistically significant. Only the fine fraction showed a linear relationship with a moderate correlation coefficient.The bubble surface area flux was shown not to be a function of the impeller velocity above a threshold value. The flux was an almost linear function of the superficial gas rate enabling to use the superficial gas rate instead of flux if the operation of an existing cell is to be estimated.INTRODUCTIONBubble area flux seems to offer a simple way of modeling flotation. It relates the flotation rate constant with the bubble surface area flux by a simple linear equation. Due to this, there has been a considerable interest in using the bubble area flux for flotation computations. It has even caused claims that a cell producing a high bubble surface area flux automatically produces a high rate constant and therefore a high recovery.This paper discusses some of the assumptions of the relationship and gives some plant results during two sampling campaigns.The bubble surface area flux s b is describing the area of bubbles available for flotation in a cell per unit area. The bubble surface area flux is related to the superficial gas rate J, by the Sauter mean diameter as follows"

Jan 1, 2001

A rough simulated borehole has been developed for the installation and dynamic testing of rock bolts a the WASM Dynamic Test Facility. The rough simulated borehole is used for rock bolts that are sensitive to equipment installation technique or borehole geometry (particularly friction rock stabilisers and resin encapsulated bolts). An extensive axial test program has quantified a difference between the static and dynamic capacity (kN/m of embedment) for friction rock stabilisers once sliding starts. The 47mm split tube bolt has a 50% reduction in embedment capacity (but with significant variation) dissipating 2.7kJ/100mm of sliding per meter of embedment, and the Omega (inflatable) bolt had a 70% reduction in embedment capacity dissipating 6.2kJ/100mm of sliding per meter of embedment. The Omega bolt dynamic capacity remainder at least equivalent to the split tube bolt static capacity.

May 1, 2009

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 Adriana Ramirez, Bradford C. Wesstrom, Blanca Olave

The Freeport McMoRan El Paso Copper Refinery optimizes electrolyte quality using a number of systems. The facility controls copper, arsenic, antimony and bismuth using electro-winning cells within the Tank House and Nickel Carbonate Plant Liberator Circuit (NCP). The NCP manages sulfuric acid content utilizing recycled electrolyte in the slimes autoclave as well as operation of the Acid Purification Unit, APU. The El Paso Refinery removes common sulfates using metal hydrolysis with sodium carbonate. Finally, a Mechanical Vapor Recompression, (MVR), at the water recovery plant removes sodium sulfate generated by the NCP. This paper will provide a summary of these operations. INTRODUCTION In the mid 1920’s Nichols Copper Company, in Laurel Hill, New York, recognized the need for a modern copper refining facility in the southwest. Because of the many railroad heads, affordable power and abundant labor supply, and the close proximity to regional copper smelters in Mexico, Arizona, and New Mexico, El Paso became the ideal location. In December 1928, ground was broken for the joint venture refinery between the Nichols Copper Company, Phelps Dodge, and the Calumet and Arizona Mining Company. In September 1930, Nichols Copper Company became a part of Phelps Dodge Corporation after a stock exchange. In July 1938, Nichols Division officially became Phelps Dodge Refining Corporation. In March 2007, Freeport McMoRan Copper & Gold acquired Phelps Dodge. Water is a precious commodity in the desert southwest, making conservation of this natural resource an important goal for the El Paso Operations. In the 1980’s, work on the treatment of slimes was improved through the use of pressure leaching of the refinery slimes using an autoclave. Due to the high tellurium content in the leached slimes solution, it was crucial to implement a method for its removal before the solution returns to the tank house electrolyte. A copper telluride cementation operation was installed for tellurium recovery and the ability for the recycle of the leachate and wash water to the refinery electrolyte. In October of 1997, ground was broken for the construction of the water recovery plant using an MVR to reuse process water, reducing water consumption by 25%. In 2002, electrolyte purification was further improved with the installation of an Acid Purification Unit, (APU) (Sheedy, Pajunen, & Wesstrom, 2007). The APU recycles 90% of the acids (both sulfuric and arsenic acids) back to the tank house electrolyte. The solution that passes through the APU is treated with soda ash to precipitate metals out of solution as carbonates and generates a sodium sulfate solution. This sodium sulfate solution is easily processed in the new water recovery plant, where the majority of the water recycles back into the plant as pure condensate. In 2012, the power plant at the refinery upgraded its Reverse Osmosis System to provide RO water to the tankhouse. This insured that the refinery would not have to bleed electrolyte for metals contained in well water such as: calcium, magnesium, iron and sodium chloride.

Jan 1, 2019

By Rolf Andreas Lauten, Adam Pratomo, Dani Ramdani, Helminton Sitanggang

A universal challenge for the mineral processing industry is the diminishment of high grade ores. Instead, low grade ores, sometimes also containing problematic gangue minerals is the reality. With lower head grades the industry has to put more effort into processing to maintain the output and achieve suitable recoveries. In an effort to reduce the impact of declining head grade, a biopolymer was evaluated as an additive in the gold leaching operation at Antam Pongkor in Indonesia. Laboratory testing revealed that biopolymer usage lead to an increased gold recovery without apparent negative impact on the other parts of the process. Further plant trials revealed both a recovery increase around 1.3% and higher throughput (9%) in the presence of the biopolymer. Some scenarios that can explain these findings will be discussed.

Jan 1, 2014

By Kri Inwood

"IntroductionIn 1879, when the Dominion government initiated its controversial program of industrial promotion, iron smelting in Canada was limited to one company producing coke iron on the mainland of Nov a Scotia and three small charcoal blast furnaces in Quebec. There was no steel production. By the eve of the first great war, iron and steel were being produced in very large quantities, the companies active in 1879 had disappeared and new centres of integrated iron and rolled steel production at Hamilton, Sydney and Sault Ste. Marie had come to resemble the industry as we know it today.The most dramatic change was that at Sydney, Nova Scotia, where in the early 1900s, two steelmaking companies established works. The Sydney developments have been explained as the result of resource discovery and technical change. W.J. Donald, in his authoritative account of the Canadian iron and steel industry, observes:""The most rapid growth of the Canadian iron and steel industry has occured since 1897... The remarkable growth has been caused largely by the new conditions of the industry. The discovery and use of Newfoundland ores, together with the availability of Cape Breton coal, has made the Nova Scotia industry not only possible but profitable ... It is a safe conclusion that the Canadian industry would not have been an important one, had it not been for the discovery of the Michipicoten and especially the Wabana (Newfoundland) ores""Donald also argues that metallurgical progress had been necessary to render the ores valuable,""Newfoundland ores ... contain a considerable amount of phosphorus, and were made available for steel-making by recent inventions.""The purpose of this paper is to re-examine Donald's story. It will be argued that the origin of steel -making at Sydney is somewhat more complicated than Donald has indicated. The difficulty with Newfoundland ore extended beyond its phosphorus content and a resolution required more than the basic open hearth furnace identified by Donald. Moreover metallurgical change was only one of several developments necessary to induce industrial investment at Sydney. Surprisingly, however, the discovery of iron ore in the late nineteenth century does not appear to be part of the explanation."

Jan 1, 1983

By W. Mueller, M. Rocheleau, E. Dimroth

The paleogeographic evolution of the Abitibi Belt is subdivided into three phases, namely: 1) a phase of the growth of a submarine volcanic chain, 2) a phase of the emergence and growth of volcanic islands and 3) a phase of uplif t and erosion of volcanic islands. Isostatic calculations suggest that the volcanic sequence in the south of the Abitibi Belt rests on oceanic basement or on the mantle; the volcanic sequence in the north of the belt rests on about 13-14 km of tonalitic basement. 10-15 km of plutonic material accreted to the volcanic islands during paleogeographic phases 1 and 2, and caused the uplif t during paleogeographic phase 3.

Jan 1, 1984

By P. Homola, M. Karlík, M. Slámová

"Aluminum sheets (AA1199, AA8006, and AA5754) were processed by accumulative roll-bonding (ARB) in the temperature range from 20 to 350°C. The microstructure of the sheets was characterized by means of scanning and transmission electron microscopy and electron backscattered diffraction. Mechanical properties were monitored by hardness measurements and tensile tests. Increasing strain (number of ARB cycles) led to incremental development of lamellar microstructure with a decrease of the spacing between high-angle grain boundaries in the normal direction of sheets. ARB process produced an important increase of strength while maintaining thickness and relatively high ductility, without accenting of the anisotropy of mechanical properties of sheets. The level of hardening decreased with the processing temperature and at 300 and 350°C ARB caused even the softening of the material due to the recovery of the deformed microstructure or partial recrystallization during heating to ARB processing temperature.INTRODUCTION Accumulative Roll Bonding (ARB) is a technique of grain refinement by severe plastic deformation (SPD) proposed by Saito et al. (1999). One ARB cycle consists in sheet cutting, surface treatment, stacking of two pieces, heating (optional), and rolling with 50% reduction in thickness. Since the sheet thickness remains unchanged by this cycle, ARB processing can be repeated as many times as desired. The goal of ARB is to impose an extremely high plastic strain on the material, resulting in structural refinement and strength increase without changing specimen dimensions. After several cycles, ultra-fine grained (UFG) materials with high strength and relatively high ductility are produced. An advantage of this method is that it does not require any special equipment as other SPD methods such as equal channel angular pressing (ECAP) (Valiev & Langdon, 2006), high pressure torsion (HPT) (Valiev et al., 2000), or cyclic extrusion and compression (CEC) (Richert et al., 1999), but only a conventional rolling mill and so it is seen as an economically viable and industrially scalable processing route. ARB processing has been successfully applied to various kinds of metallic materials at room or elevated temperatures (Tsuji, 2005). Besides processing single metals and alloys, ARB has also been used for creating ultra-fine grained and nanograined metallic composites (Wu et al., 2010; Qu et al., 2014)."

Jan 1, 2018

By Faan Bornman

"Reeves and Platt1 stated that dense medium separation is one of the most complex unit processes in mineral processing today particularly if cyclones are used. It is also the most efficient gravity concentrating process available to process engineers. The complexity of the process and large number of design and operating variables means that the process has largely remained more an art than a science. Dense medium separation is well established in the diamond, coal and iron ore industries but is gaining popularity as a pre-concentration step in other industries. The maintenance issues are addressed that will affect the efficiency of the operation.INTRODUCTION The purpose of the dense medium separation (DMS) process is to separate the valuable material from the waste based on gravity differences. However, the specific gravity difference between the two fractions must be large enough to achieve high efficiencies. Heavy particles sink through the dense liquid and light particles float. DMS is also used for the pre-concentration of minerals before further downstream processes like communition, in order to minimise the treatment costs. Examples are the pre-concentration of diamond ores or metalliferous ores like nickel, copper and cobalt. Dense medium separation is also used to upgrade the material to meet different market specifications, for example in coal and iron ore applications. A typical dense medium separation process for a diamond application is shown in Figure 1."

Jan 1, 2014

By M. Cala

Underground coal gasification is technology which enables energy to be extracted from coal beds where mining by means of classical methods is either impossible or uneconomical. The process of coal gasification itself is a complex phenomenon which includes chemical and physical processes: thermal, hydrological and mechanical. Additionally, the analysis of underground coal gasification is difficult to carry out for environment reasons, this being due to the local characteristics of the areas where it is carried out. This paper deals with interaction of geo-reactor with surrounding rock mass, it omits the chemical processes inside geo-reactor itself. Due to the complexity of the processes proceeding and during underground coal gasification coupled with minimal practical experience in using this technology, it is difficult to estimate its influence on the surrounding rock mass. Within this scope, the use of numerical programs can be useful. This paper presents a trial of modeling the processes accompanying underground coal gasification. The processes proceeding and during the underground coal gasification are characterized, and the significant, specific phenomena are discussed, with respect to the influence on the surrounding rock mass. For the chosen processes, examples of numerical calculations are presented. These enabled conclusions to be drawn and also provided directions for the modeling of the underground coal gasification processes.

Aug 1, 2013

By L. Hacini

The start-up is the most critical phase of the cell life, as an uncontrolled start-up could lead to early infiltrations, instabilities, and in some cases to the cell death. Lots of efforts are put to increase the lifespan of cells, as it has a major impact on both the operating costs and the environmental footprint of the aluminum industry. Obviously, a true size test on a cell is a resources- and time-consuming approach that could be used only to validate mature concepts. Moreover, numerical modelling is a low-cost and versatile tool capable to test a wide range of potential ideas and concepts. In the present article, a thermal electrical mechanical slice model is presented. This model describes the preheating and bath periods of a P155 aluminum cell start-up, as used at the Grande Baie smelter. The impact of sodium diffusion and expansion is also included in the model. This model will be useful to study different problematical issues such as the global behaviour of lining materials, shell and cradle deformations during start-up and several start-up scenarios. Such a model will also be able to answer some interrogations regarding early infiltrations and their impact on the lifespan of the electrolysis cell.

Jan 1, 2011

By K. Yoshida

Recently, light magnesium alloy with superior heat radiating ability has been attracting attention in various fields. However cold plastic working of the alloy is very difficult and hot working necessary. Furthermore, the magnesium of products with complicated shapes is difficult, the processing cost is high, and the applicability of the alloy is limited. In this study, a technique for obtaining fine wires and tubes by cold drawing is examined to obtain wires and tubes with high strength, quality and surface morphology, while decreasing production cost. In addition, the shearing strain of magnesium alloy wires and tubes drawn under various drawing conditions was calculated by FEM analysis. It was clarified that cold drawing of magnesium alloy is possible. It was also demonstrated that greater reduction of the cross-sectional area could be realized during cold wire and tube drawing by optimizing the drawing conditions.

Jan 1, 2006

By J. R. Meyer, P. L. Dean

"The Department of Mines and Energy is at present investigating the dimension-stone potential of the Nain anorthosite complex. These rocks are known to host occurrences of labradorite, a semiprecious gemstone known for its beautiful play of colours (chatoyance). Test blocks that contain 5% to 18% chatoyant labradorite were extracted from three prospects south of Nain. These have been slabbed and polished for further evaluation.Second-grade labradorite stockpiled around the Grenfell quarry on Tabor Island is also being evaluated as a potential source of aggregate for use in terrazzo tiles, precast concrete and epoxy-backed wall panels.IntroductionThe Nain anorthosite complex consists of approximately 10000 km2 of anorthosite and related basic rocks , which are well exposed along the coast of Northern Labrador (Fig. 1) (Emslie et al., 1972). These rocks have been known for centuries to host deposits of gem-quality labradorite. The chatoyant nature (i.e. the play of colours or labradorescence) of this semiprecious feldspar has been utilized mostly in the making of jewelry and other polished, handcrafted products. In the early sixties, Brinex Limited (now Brinco Limited) attempted larger scale commercial exploitation of labradorite, including use 'as building stone and in polished precast concrete for facings on buildings' (Brummer, 1984). After six years of work, which included market studies, Brinex decided that, at that time, the demand did not warrant further production.In recent years, there has been a dramatic increase in the markets for dimension-stone. In the period from 1980 to 1985, the demand in the United States for granite, much of which is imported, has increased 1735070 (Marble Institute of America, 1986). The dimension-stone industry's remarkable growth rate has, in part, resulted from new technology that makes it easier and faster to quarry and cut stone. This has allowed natural storie to compete with other building materials. Now, it is not only used for exterior cladding and walkways, but also on interior walls and floors, and in home and office furnishings, such as countertops for kitchens and bathrooms, table and desk tops, stairways, window sills, and fireplaces."

Jan 1, 1988

By Kuwauchi. Y., M. Barati

Recycling of dust using a rotary hearth furnace (RHF) has gained considerable attention in the past two decades for the sustainable production of steel with less environmental impact. In order to further promote the recycling of electric arc furnace dust and carbonaceous wastes using the RHF process, a mathematical model was developed to predict the reaction behaviour of dust-reductant composites. The reduction kinetics of zinc and iron oxides as well as the volatilization behaviour of volatile matter in the reluctant were considered. The modeling approach and some preliminary results are presented in this article.

Jan 1, 2011

By F. Malek

At Creighton Mine, magnitude events are a regular occurrence due to depth and major seismically-active structures. Over the last ten years, major advances have been made in research and development to develop strategies for the management of these major events. Today, the number of rockbursts has been drastically reduced at the mine and damage due to seismic events, when they occur, is often minimal. This paper describes the evolution and implementation of appropriate geomechanics strategies, designs, and practical ground control measures undertaken for the management of seismicity at Vale Inco?s Creighton Mine. A description of the research and development approach, implementation, and ground control strategy is provided for placement of enhanced support systems to manage the consequences of magnitude events at Creighton

May 1, 2009

By F. Pinto, C. A. Prato, R. J. Rocca, P. F. J. Huerta Soaje

"The seismic hazard for civil engineering structures is generally defined in terms of deterministic or probabilistic acceleration response spectra at an equivalent rock outcropping. The design of tunnels, however, requires the definition of demands in terms of accelerations at ground surface (near the portals) and in terms of both accelerations and velocities at different depths within the alignment. The design near the portals is controlled by inertial effects and is often times impacted by the possibility of slope instability and rockfall, whereas the design at deep sections is controlled by kinematic effects. These effects are accounted for in practice by introducing deformation patterns in the structure that are related to an assumed wavefield, often times ignoring the effect of the structural stiffness in the response. This paper presents a study regarding the definition of seismic demands for different sections of 14-km long tunnel in the Andes (Argentina-Chile), with a maximum overburden of 1750 m in a seismically active region. The tunnel will pass through volcanic massifs mainly composed by andesites and rhyolites.The study includes the definition of spectrum-compatible seismograms, deconvolution, and definition of accelerations and peak particle velocities for different overburden conditions. A kinematic interaction study for a 500-m tall ventilation chimney shaft is also described, where a simple formulation for the interaction analysis is considered in order to more accurately evaluate shear and bending demands. INTRODUCTIONThe seismic design of linear underground structures, such as shafts and tunnels, generally considers the inertial forces near the shallow sectors (e.g., portals) and the kinematically imposed deformations for the deep sections (e.g., Hashash et al. 2001). The inertial forces are often times evaluated on the basis of design spectra recommended by seismic hazard studies. The kinematic demands for the deeper sections, however, needs to be defined in terms of additional information which is not always indicated by the seismic hazard studies, e.g.; peak particle velocities and accelerations, and their variation with depth. These parameters can be determined by means of a site response analysis, whereby outcrop motions can be deconvoluted in order to evaluate motions inside the ground mass (e.g., Schnabel et al., 1972). Hashash et al. (2001) defines factors that may be used in order to account for attenuation of motions inside the ground mass. However, these factors are provided for depths up to 30 m only, whereas depths of tunnels structures can range up to thousands of meters."

Jan 1, 2015

By Alex Cormode, Carlos Perucca

"Sylvinite ore from the Saskatoon area typically contains about 5% insolubles, occurring as clays and carbonates. These insoluble slimes must be removed sufficiently well to permit an efficient subsequent potassium chloride flotation, due to their high adsorptive capacity for amines used as potash collectors. The insolubles are liberated from sylvinite by high attrition scrubbing in a slurry. The liberated slimes are separated by multistage cycloning or by a selective flocculation-flotation process.An outline of the potash processing operations at Agrium Vanscoy Potash Operations is given, emphasizing the insoluble slimes froth flotation separation process. This process was originally implemented at the Agrium plant in the mid- 1970's and replaced a hydrocyclone system.IntroductionAgrium Vanscoy Potash Operations is located 40 Km southwest of Saskatoon, almost midway between the communities of Vanscoy and Delisle. Processing operations started in 1969, and the annual production capability was subsequently increased to the current 1.8 MM tonnes per year of muriate of potash.The mining operation at Agrium Potash which was described in a paper by Jones and Pruggerl , is done underground using four large continuous double rotor boring machines for the main production with development done by heliminers. Annual ore production is 5.5 MM tonnedannum. Ore is hoisted 1,100 m to surface for processing."

Jan 1, 1999

By Michael Farley, Paul Dufour

"Relationships, Partnerships,Marriages (RPM)RPM has a nice musical ring to it, but it is in fact synonymous with science and technology, university-government -corporate links and the more genera l issue of university roles in technology development. Pick up any report on one of these issues, and chances are that you will find one of these key words in the title. Play it, and you will find that the revolutions per minute are increasing. It is difficult to keep track of the wide variety of institutional experiments now developing in Canadian universities in attempts to marry science and research with technology commercialization and technology transfer.Why is the role of Canadian universities in this matter important? There are at least five good reasons:1. It is important because these knowledge institutions are producer s of scientific research, a major component of technology. Today the gap between the two is rapidly shrinking.2. It ' is important because Canadian industry is turning to universities for tech no logy development and new knowledge. Figure 1 shows that universities are becoming an important source of technology available to Canadian firm s; more important in fact than government. Figure 2 illustrates this trend more graphically in showing that university collaboration is one of the preferred methods of industry participating in co-operative R&D efforts:3. The role of Canadian universities in technology development is also important because the provincial and federal governments have embarked on various programs and policies for promoting the use of technology and science for economic benefit. Universities are playing an increasing role here. For example, the submission of IDEA Corporation (a venture capital operation funded by the government) in Ontario to the Bovey Commission on the Future Development of Ontario Universities clearly spelled out its ideas for commercialization of university research in Ontario . Among other things, the brief suggested that Ontario's universities need to be better equipped to transfer technology, and the reward structure in university research must incorporate industrial interests."

Jan 1, 1986

By D. S. Salonine

Aluminum alloys are widely used in modern industry. Tubes and hollow shapes give great opportunities for structural purposes as well as fluid transport due to their stiffness and lightness, Extrusions on a mandrel or through a bridge die, that requires splitting of the billet with re-welding, produce hollow shapes with varied contours, fins and multiple cavities. Moving and stationary mandrels, mandrel lubrication, tooling for ribbed-tube heat exchangers, and for drilling pipes are considered. Bridge dies can be classified by the bridge position relative to the die face, by mandrel support structure, and by assembly type, The main parameters influencing the quality of the die-welded seams are considered, The difficulties of extruding various alloys through bridge dies are discussed in terms of metallurgical factors, Some approaches to the calculation of the stresses in a bridge are presented.

Jan 1, 2005