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By P. Woo, N. Brodusch, R. Gauvin, H. Demers

For developing new technologies, it is important to characterize the microstructure of materials with high spatial resolution at the nanoscale. To achieve high resolution, field emission scanning electron microscopes (FE-SEM) were developed. These microscopes allow working at low accelerating voltage, below 5 kV, to take advantage of the reduction of the interaction volume with accelerating voltage. Furthermore, their higher gun brightness compared to conventional thermo-electronic emitters, allow a probe size at the nanoscale. At low accelerating voltage, the emission volume of backscatter and secondary electron (SE) of the type II signals approach that of SEI signals. However, it is not enough to reach the highest resolution. A magnetic field above the sample improves the spatial resolution by collecting mostly high-resolution signals. In addition, the energy-filtration of the electron signals allows selecting the type of contrast detected: topographic, compositional, or crystallographic. The development of these new technologies permits to extend the imaging capabilities of the SEM towards new nanoscale applications.

Jan 1, 2014

By Lawrence Devon Smith

What is a Failed Project? For mining projects, some key indicators of a ?failed? project are: ? Cost is more than it should be (particularly capital) ? Schedule ? It takes longer to build than expected ? It takes longer to ramp-up than expected ? It does not do what it is supposed to do ? Poor performance; output, product specifications; ? Low revenue ? High costs ? No one is happy about it: Management, Shareholders, Bankers ? Does a project fail if it does not meet expectations that were unrealistic and unattainable? ? Caution: Failure may not become evident until years later

May 1, 2010

By Ö Yilmaz

In this study, the behaviour of rock mass subjected to blasting load is investigated using three dimensional finite difference numerical modelling. In the analyses, Mohr-Coulomb failure criterion has been used for the characterisation of the rock mass strength. Stresses acting on the borehole boundary have been simulated by an exponential function which reaches its maximum within a short time and then falls to zero value in a considerable time period. The strain rate effect on the mechanical properties of rock material has also been taken into account in the analyses. Four different explosive-rock mass combinations have been studied to investigate blast induced damage zone. It has been observed that proposed equation for the dynamic compressive strength of rock material fits very well to general suggestions. Results have shown that blast damage analysis model recommended with this study is successful.

Aug 1, 2013

Introduction ?MT involves the measurement of naturally occurring magnetic and electric field oscillations. ?The ratio of E/H (wave impedance) is measured as a function of frequency to give resistivitydepth information. ?The ratio of vertical and horizontal magnetic fields (tipper) gives information about the location of (channeled) current systems.

May 1, 2008

By B. Jakovljevic, M. D. Soderstrom, T. McCallum, A. J. Quilodrán

Cytec has developed a new organophosphorus based solvent extraction (SX) reagent for rare earth separations. The new product, CYANEX® 572, has been formulated to allow efficient extraction while minimizing the strip acid requirements. The optimization of formulation strength is expected to significantly reduce the operating costs of these circuits. Modeling capabilities for CYANEX® 572 (similar to those used successfully in Cu and Co/Ni SX) have also been developed to aid in the design and optimization of the SX circuits. Simulations will be shown comparing CYANEX® 572 to a traditional rare earth extractant.

Jan 1, 2014

By J. H. Curran

Agenda ? Challenges of developed world mining ? Software aids for creative and practical engineering ? Rocscience software philosophy ? Rocscience suite of geomechanics programs ? Case study ? design of de-stress slot Mining Challenges of the Developed World ? Dwindling reserves ? Great depths ? Strict operating and environmental regulations ? Competition from lower cost operations in developing countries

Apr 1, 2005

By S. Esfahani, M. Barati, K. Danaei

"Substituting Portland cement with slag cement is one of the most economically attractive uses of slags. For this application, high cooling rates are required to form an amorphous structure. However, this is counteracted by the need to use small coolant flowrate to allow recovery of slag thermal energy as high quality heat to the coolant fluid. Therefore, a relationship between cooling rate of slag and its structure is essential to recover the heat effectively while making an amorphous slag.A modified Single Hot Thermocouple Technique (SHTT) was employed to investigate the crystallization behavior of slags by plotting their TTT (Time-Temperature, Transformation) diagrams. Seven different slag compositions containing CaO, SiO2, Al2O3, MgO were prepared at varying basicity (CaO/SiO2 =0.5-1.4).The results indicate that with increasing basicity, the TTT curves of glassy to crystalline transformation shift to the left which means higher crystallization tendency. This agrees with the fact that with the increase of basicity, the Si-O bonds are weakened, which in turn facilitates the re-ordering and crystallization of the silicate structure."

Jan 1, 2014

By Terry Aben

Outline ?Review of standards that can be used to identify current coating conditions and optimal points to perform coating maintenance. ?Identify how standards can be used to extrapolate the future condition of coatings to achieve predictive maintenance planning. ?Demonstrate how the above can be combined with project estimating to generate a data driven, quantitative, predictive, risk-based asset integrity maintenance program for Protective Coatings. The Value of Asset Integrity Programs ?Maximize the benefit produced from the investment in maintenance spending. ?Get the best bang for your buck! ?Don?t perform maintenance work before it is necessary ?Money is invested early with no increase in the service life extension. ?Don?t delay until it is too late. ?Planned Maintenance is far less costly than Reactive Maintenance. ?Identify the Optimal Point for Maintenance.

Nov 1, 2011

By V. Evans

Mine lateral development advance rates currently average about 5 metres (16.5 ft.) per day. Granduc Tunnel hit 35.1 metres (115 ft.) on their best day, 12 km from the portal, single heading forty-three years ago. This Canadian mining record remains an excellent example of rapid drill and blast excavation with suggestions for improving current practice.

May 1, 2011

By C. Jay Hodgson, Adrienne C. L. Larocque

The Mobrun VMS deposit in northwestern Quebec does not fit the classic Noranda type model, but exhibits characteristics more consistent with a Mattabi-type deposit. The orebodies are underlain by fragmental volcanic rocks indicative of explosive volcanism in shallow water. Felsic volcanic rocks are more abundant than mafic rocks. Alteration assemblages comprise chlorite, carbonate, sericite, and quartz. Broad semi-conformable alteration occurs high in the footwall to the 1100 lens. Mobrun occurs higher in the stratigraphic sequence than most of the other deposits in the Noranda camp. In this part of the stratigraphy, zones of pervasive carbonatization may be more useful guides for exploration than zones of silicification.

Jan 1, 1993

By M. Connell, S. Bedrossian

Alkali cracking followed by chloride-based leaching is one of the prominent methods for rare earth element processing. Regeneration of the leach lixiviant, namely hydrochloric acid, is a critical operation in the process. A number of different process routes are available for recovery of hydrochloric acid from chloride solutions. The objective of this paper is to discuss various recovery routes and analyze the impact of several input variables on the variable operating cost.

Jan 1, 2014

By Andrew Thrift

Overview ? Problem ? Research question ? Literature review ? Methodology ? Results ? Discussion and recommendations ? New developments Problem ? Increasingly higher expectations ? Inadequate consultation leads to conflict rather than collaboration ? Consultation practice is often weak on decision-making ? Influence of consultation on planning is Unclear Research question ? Are Structured Decision Processes (based on decision analysis) an effective methodology for involving stakeholders in consultative decisionmaking in the mining industry?

May 1, 2006

By Ron Ferris

The Westinghouse Temptifier TM, using heat pump principles, recovers lowgrade waste heat in the 600P to 1600P temperature range and amplifies it to usable levels of up to 2200P. Coefficients of performance (C.P.D.) normally encountered are from 3.0 to 6.0, with capacities from 200,000 to 10 million Btu/hr.

Jan 1, 1979

By Alireza Sarafi, Alijan Aftabi

"A hydrocyclic system used for mineral separation at the laboratory scale results in the separation of more than 90% of micas. The system functions only by water and might offer advantages where other methods of mica separation are not available. INTRODUCTIONVarious methods for the separation of micas, wollastonite, and garnet, e.g., screening, flotation, magnetic separation, and heavy liquids, are well known (e.g., Spence, 1929; Bates,I960; Gillson et al., 1960; Benjamin, 1971; Connor and Kolhnar, 1991; Collings and Andrews, 1991). However, where these methods are not available, the separation of micas by a hydrocyclic system developed by Sarafi and Aftabi (1991) may prove to be economic. This note is a brief description of the hydrocyclic system. Minerals and MethodFor testing the recovery of mica and other minerals from different rocks (garnet-mica schist, skarn, and pegmatite), standard minerals were tested first, and then rock samples. Pure mineral standards were prepared from coarse-grained samples of pegmatite, mica schist and skarn; the grain size of the minerals separated was more than I cm. The Hydrocyclic System and Mineral SeparationThe hydrocyclic system is shown schematically in Figure 1. In the first step in mineral separation, mineral and rock samples were crushed, milled, and then sieved to minus 250 plus 125 microns. Approximately 10 gm to 25 gm of the sample were inserted in decanter Dt • The motor pwnps, M1 and M2, were then turned on and the water valve rl was opened. At this time, water was flowing turbulently (30 em3/sec. to 50 em3/sec.) and minerals were separated according to their crystallographic nature, density and!or habit. The fInal separation was done by exit valves r2, r3 and r4, while the motor pwnps were still operating. After each experiment, the rt , r2' r3 and r4 valves were closed and the motor pumps were turned off. Following this, minerals in each decanter and the mter were collected, dried and weighed. The whole time of the experiment was optimized to be about 10 minutes, but varied from 3 to 15 minutes for micas and garnets. respectively."

Jan 1, 1994

By S. Knapp

Inconel 600 pipes welded to Carbon-Steel are used in CANDU nuclear reactors. Fracture of these welded tubes would have important consequences in term of safety, and therefore their mechanical properties need to be better understood. In this study, the weld region was analyzed at various length-scales using optical microscopy, micro hardness testing, small and large scale tensile testing and digital image correlation (DIC). Large grains were observed in the weld region and smaller grains in the Inconel and carbon steel base metals. Micro-hardness profiles showed variations across the weld and through thickness and were justified in terms of residual stresses in the sample. Large tensile samples were extracted from the welded pipe and were used to identify the material in which fracture initiates. In addition, the local strains in each material were obtained using digital image correlation. Local stress-strain curves were built from the DIC data and compared to stress-strain curves obtained from miniature tensile samples extracted from the carbon steel, Inconel and weld regions. The results demonstrate the advantage of using DIC for extracting local material properties in dissimilar weld systems. Variations in the materials stress-strain curves thought thickness are also presented and emphasize the need for obtaining a complete map of the mechanical properties in the weld region for predictive models to be accurate. Preliminary fracture studies will also be presented.

Jan 1, 2011

By F. Moraw

The use of redox fuel cells in which oxygen is replaced by other oxidants such as ferric ions can have significant advantages [1-3]. For example, the cathodic reaction rate (e.g., exchange current density) can be increased by several orders of magnitude compared to the oxygen reduction reaction, and platinum group metal (PGM) catalysts are not required. As a result of the higher aqueous solubility of the oxidant in a redox fuel cell compared to that of oxygen the rate of mass transfer (e.g., limiting current density) is greater by several orders of magnitude. The redox fuel cell can achieve high efficiencies and has other fuel cell advantages. The main issue with the redox fuel cell cathode is the regeneration of the oxidant where low conversion efficiencies are achieved even with platinum group metal (PGM) catalysts. In the work discussed here the Fe3+/Fe2+ redox fuel cell cathode is characterized over a range of electrolyte concentrations and operating conditions, and electrode materials. Cyclic voltammetry and electrochemical impedance spectroscopy are mainly used for electrochemical characterization and mechanistic determination of the cathode redox couple. Further characterization with selected compositions and materials is done in a redox fuel cell (hydrogen - Fe3+/Fe2+). The mechanism and the advantages and disadvantages of the fuel cell redox cathode are discussed with respect to other approaches and other redox couples.

Jan 1, 2005

By C. R. Edwards

"Equity Silver Mines Limited owns and operates an open pit silver 111ine located 37 km southeast of Houston in the Omineca District of British Columbia, Figure l. The property is approximately 300 km west of Prince George and 417 km east of the Port of Prince Rupert. This is the largest silver mine in Canada and one of the five largest silver producers in the western world.Equity is a subsidiary of Placer Development Limited, which owns 70 of Equity's issued and outstanding Common Shares. Placer was responsible for financing and developing the property and now provides general management and administrative services.All mining is by open pit methods, using three 1600 P&H shovels, eight 45 t Caterpillar and three 77 t Wabco trucks, three 40R rotary drills, two D8 dozers, one 9888 front-end loader and other ancillary equipment. We are now phasing out the Southern Tail pit and bringing the Main Zone into productior; see Figure 2.Comminution in the concentrator is achieved via primary, secondary, and tertiary crushers followed by rod and ball mills. The flotation circuit, with Southern Tail ore, produces a concentrate containing between 3 000 and 6 500 g of silver per tonne, 201 copper, and 25 g of gold per tonne. Running Main Zone ore, concentrate grades will decrease to about 4 500 g of silver per tonne, 17% copper, and 18 g of gold per tonne. Design milling capacity is 5 300 tpd, which is often exceeded.The flotation concentrate contains relatively high levels of antimony and arsenic. Because of these impurities Equity was unable to obtain economically acceptable long-term sales contracts for flotation concentrate. For this reason a leaching process was developed, and a plant designed, built and placed in operation. Due to the complex and unique technology involved, many start-up problems were encountered but by March 1983 the leach plant was considered ""fully operational."" This paper describes some of our progress and problems in bringing the Equity leach plant through its start-up period."

Jan 1, 1984

By D. J. Bowen

"The Great Dyke extends for 540 krn along strike, to unknown depth, and varies in width from 3 krn to 11 krn. Rb/Sr age determinations gives values of approximately 2470 Ma.The Dyke consists of a variety of mafic and ultramafic rocks, many altered to serpentinites. These include, from top to bottom, successions of gabbro/norites, pyroxenites, peridotiteslharzburgites, and dunites/picrites.The layers dip in from either margin, steepest at the edges (20°) and flattening toward the central sections. Four separate complexes are present. From north to south these are termed the Musengezi, Hartley, Selukwe and Wedza Complexes, and are described as 'boat-shaped' or 'pig-troughed'. All are similar in petrological sequences. Physiographically, the Dyke is spectacular in the north, where as a mountain range it meets the Zarnbezi Escarpment. Elsewhere in the central parts there is little surface expression and wide open treeless vleis. Dyke rocks cut through granite and schist belt terrain and are termed 'The Magnesia Belt'.Vast mineral resources exist. These include chrome, asbestos, platinoids, nickel, copper and gold. Up to eleven chrome seams numbered from top to bottom occur in the lower ultramafic sequences. Seams are narrow at 10 em to 30 em but of high grade. The platinum occurs 10 m to 40 m below the norite/pyroxenite contact.A 60 m wide zone of Light Sulfide Mineralization (LSM) of less than 1070 sulfides extends from the lower gabbronorites into the upper pyroxenites. In this LSM, four enriched zones carry up to 5% sulfides. The most widespread is termed the Main Sulfide Zone (MSZ), below which is No. 2, No.3 and No.4 Sulfide Zones. The MSZ carrying pyrite, pyrrhotite and chalcopyrite is a multielement ore with components of PGE (pt-Pd-Rh), nickel, copper and cobalt, and gold and silver.Extensive exploration programs have been carried out and the intention is to begin large-scale mining. However, with Russia supplying metals to the western markets, South Africa's cutback on production, and an end to the Cold War, delays have arisen."

Jan 1, 1994

By Brent Robertson

Failure to meet quality objectives during the execution of any industrial project has lasting negative impacts on facility life cycle performance. Cost overruns, schedule delays, and rework are characteristics of project quality issues that arise during the project. Commissioning and start-up problems, low production, production bottlenecks, breakdowns and the necessity for operational work-arounds are characteristics of project quality issues that appear after project completion. Risks such as production facility downtime, shortened equipment life, and potential HSE violations must be clearly identified and addressed during project planning phases. Appropriate Quality Assurance (QA) and Quality Control (QC) focus must be placed on identified high-risk areas. In order to be effective, quality systems must be flexible, non-confrontational, consistent, and adaptable to projects of any size ? from capital mega-projects to small maintenance projects. All project participants must be aligned in how they are approaching quality and the difference between QA and QC must be clear to everyone on the project. Emphasis must be placed on QA activities to minimize project cost, reduce rework, manage change, and reduce the production facility operational risk. QA is focused on the work processes used to generate the design and confirming that the processes are present and being followed. Issues in the work processes guarantee that the output drawings and specifications will be less than optimal. The identification and monitoring of quality-critical processes provides a focus for QA activities. QC activities are then used to generate proof that the project was implemented correctly and become a key part of the turnover.

Nov 1, 2011

By Jacob Wood, Robert Matusewicz

The Outotec® Ausmelt Top Submerged Lance (TSL) Process has achieved widespread commercial acceptance over the past 40 years for the processing of copper, nickel, lead, tin, zinc and precious metal bearing feeds. The continual development and evolution of the technology during this period has resulted in a more intense smelting process with higher energy efficiency and lower operating costs. More recently, considerable effort has been invested in decarbonisation of the process through improvements such as increased oxygen usage, dry feed injection and use of low-carbon auxiliary fuels. This paper covers a number of these recent advances to the technology and highlights their impacts on energy consumption and CO2 emissions for a range of non-ferrous smelting flowsheets. INTRODUCTION Relentless demand for improvements in the profitability, safety and environmental performance of non-ferrous smelting plants has driven a continual development and evolution of processing technologies in this industry. In response to these demands, a number of bath smelting technologies have emerged over the past 40 years and have been implemented for the treatment of primary and secondary feedstocks. The Outotec® Ausmelt Top Submerged Lance (TSL) Process (henceforth Ausmelt Process) is one such bath smelting technology which has been widely adopted in a large number of greenfield projects and brownfield plant modernisations (Wood & Hughes, 2016). Emissions of CO2 from the production of non-ferrous metals represent approximately 4-5% of global totals (Rankin, 2012), comparable with the almost 10% attributed to iron and steel production. Despite significant improvements in the energy efficiency of modern smelting technologies (Coursol, Mackey, Kapusta & Cardona Valencia, 2015), primarily through increased oxygen usage, further innovation and development is still required to address their reliance on fossil fuels such as coke and coal. Transformation of the non-ferrous smelting industry to low-carbon technologies and process flowsheets is lagging behind the power and transport sectors, which have witnessed significant growth in clean/renewable energy technologies to reduce CO2 emissions and address the issue of anthropogenic climate change (IRENA, 2018; IEA, 2018).

Jan 1, 2019