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By Kenneth G. Thomas

Since approximately 2003 we have witnessed the unprecedented escalation in commodity prices. Coupled with economic chaos following the 2008 economic downturn this has caused difficulties in controlling schedule, capital costs and operating costs for mining projects. Once again escalation has returned to commodity prices fuelled by growth in the BRIC countries especially China and Brazil. This is further exasperated by the missing generation of skilled technical personnel not graduating from universities in the 1980s and 1990s owing to depressed commodity prices. This paper examines the six tenets for successful project implementation.

Jan 1, 2011

By Brian C. Asbury

Gold-bearing quartz veins with auriferou pyritic wall rock alteration haloes at the Komis deposit near Waddy Lake in northern Saskatchewan occur in fractured Archean intermediate volcanic rock flanking a plutonic felsic intrusion. Three ore zones totalling 1.5 million tonnes grading five g/t gold have resulted from a combination of patterns of high density of fracture-filling quartz veins created by contrasting competencies of four predominant rock types and preferential gold deposition in magnetitebearing andesite host rock. Pre-glacial surface weathering remobilized gold from a nearby pyritized intermediateto- felsic dyke to form the EP Zone with a wide variety of supergene accessory minerals. Much of the EP Zone wa eroded by glacial action to forn1 a highly anomalous gold-bearing till dispersion train which facilitated its di covery.

Jan 1, 1986

"The Crescent, DM, and Pothook zones are copper-gold porphyry deposits which formed in association with alkalic intrusions of the early Jurassic Iron Mask batholith. The characteristics of the Crescent and DM deposits are nearly identical. Both formed along the contact between the Cherry Creek monzodiorite and Pothook diorite phases of the batholith. Permeable intrusion breccias along the contact concentrated the flow of hydrothermal fluids. Early, pre-ore alteration is represented by pervasive, sulphide-barren potassium metasomatism. The precipitation of copper-gold ore occurred during subsequent fracture-controlled potassic alteration, and is most strongly developed in chlorite-sulphide veins and their alteration envelopes. A central zone of potassic alteration is surrounded by a propylitic, pyritic halo in both deposits. The DM zone is unique among alkalic porphyry deposits in its high abundance of quartz-sulphide veins.The Pothook deposit formed at the westernmost contact of the Iron Mask batholith with enclosing Nicola Group volcanic rocks. Pervasive potassium metasomatism, similar in style to that at Crescent and DM, is associated with intrusion of the Cherry Creek monzonite. Pervasive and fracture-controlled albitic alteration is associated with intrusion of the Sugarloaf diorite and introduced minor copper-gold mineralization. Most of the copper-gold mineralization was introduced during formation of veins and breccia matrices dominated by magnetite/hematite and sulphide. Late-stage chlorite veining may have remobilized or introduced additional gold mineralization.Copper and gold assays in the Crescent deposit are well-correlated and have a nearly constant Cu:Au ratio, suggesting that the metals coprecipitated during a single hydrothermal event. In the Pothook deposit, copper and gold do not correlate closely, lack spatial correspondence, and suggest that transport and/or deposition of the two metals were not identically controlled and that they may have been introduced at different times by separate hydrothermal events."

Jan 1, 1995

By J. Gao, H. O. Gekonde, S. V. Subramanian

"The functional role of inclusions at low cutting speeds is to promote ductile fracture in chip formation process, whereas the role of inclusions at high cutting speeds is to prevent tool crater wear by suppressing the tribological phenomenon of seizure at the tool-chip interface. Glassy oxide inclusions are engineered into the workpiece to form a viscous layer in-situ at the tool-chip interface at high cutting speeds. The viscous layer lubricates the tool-chip interface to prevent the seizure. In comparison with the large volume fraction of inclusions needed for promoting ductile fracture at low cutting speeds, the amount of inclusions required for lubricating the toolchip interface at high cutting speeds is very small and is in the range that is typical of clean steels. The chip fracture process at high cutting speeds is aided by strain rate hardening of the matrix, which facilitates chip disposal of relatively clean steel.Inclusion engineering for high speed machining involves the control of the rheology and composition of inclusions to meet target viscosity at the tool-chip interface. The application of thermodynamic models in controlled production of inclusions in steels designed for high speed machining is discussed."

Jan 1, 1998

By X. Cao, A. Birur, R. R. Chromik, J. Cuddy, P. Wanjara, J. Gholipour Baradari, T. Shariff

In this study, 3.1 mm thick Ti-5553 (Ti-5Al-5V-5Mo-3Cr) butt joints were autogenously welded using a 4 kW continuous wave Nd:YAG laser. The effect of welding speed and defocusing distance on the weld quality was investigated in terms of the surface morphology, welding defects, microstructure and hardness. Welds with full penetration were achieved at a defocusing distance ranging from -1 mm to 0 mm and welding speeds from 2.25 to 6.0 m/min. Underfill and porosity were the two main defects most frequently observed but within the optimum process window these defects could be maintained to meet aerospace specification tolerances. The fusion zone (FZ) consisted entirely of retained beta with a refined dendritic morphology. Compared to the bimodal alpha (a) + beta (ß) microstructure of the base metal (BM), the dissolution of the a phase was observed in the heat affected zone (HAZ), which led to an 11 % decrease in hardness from the BM to the FZ. To determine the tensile properties of the welded samples, an automated 3D deformation measurement system was used to measure the local strain in the weld region. The yield strength (YS) and ultimate tensile strength (UTS) increased with increasing welding speed with a highest joint efficiency of 75 % being achieved, albeit with a concomitant reduction in the ductility.

Jan 1, 2010

By M. Timmins

Campbell Mine operates a 100 tpd gold autoclave that treats sulphide concentrates at 305 psi and 200 °C. Autoclave feed consists of fresh pretreated concentrate, an acidic oxide slurry recycle as well as other high arsenic sources. The brickwork that is used to construct the five compartments of the vessel must be inspected and repaired periodically. Shutdowns are scheduled to inspect this brickwork and at times replace entire sections of the brick walls or lining. It also provides an opportunity to repair or replace other internal features such as agitator blades or oxygen spargers. Mechanics and contractors are scheduled around the clock to perform the maintenance requirements. There are many safety considerations and precautions that must be taken in order to protect the well-being of the workers and minimize damage to sensitive pieces of equipment. Heat, arsenic and lead contamination and confined space issues are just a few of the hazards involved. The following paper will describe how these safety concerns are addressed and will serve as a guide for future autoclave shutdowns.

Jan 1, 2004

By T. N. MacAuley

"The Ingerbelle and Copper Mountain deposits are located near Princeton in southern British Columbia. They are owned by Newmont Mining Corporation's wholly owned subsidiary, Similkameen Mining Company Ltd. The property includes the Copper Mountain mine, a former producer. Ore reserves recoverable by open-pit mining are estimated to be 76 million tons containing 0.53% copper. Production commenced during 1972 at a rate in excess of designed capacity (15,000 tpd). All of the known major copper deposits in this area lie in a 14,000- by 3,500-foot belt of Triassic volcanics (Nicola Group) that is situated between a well-defined syenitemonzonite- diorite stock on the south and a variable intrusive complex on the north. The Nicola rocks consist of andesitic tuffs and agglomerates with lesser amounts of flows and some lensy siltstone layers. The orebodies are essentially disseminated sulphide deposits, although fracture-fillings are also important in many areas. Total sulphide content is usually less than 5%. At lngerbelle, and at Pit 2 and most of Pit 1 at Copper Mountain, the sulphides are chalcopyrite-pyrite. In part of Pit 1 and most of the former underground mine they are chalcopyrite-bornite. At lngerbelle the predominant alteration associated with mineralization is a pale greenish-gray bleaching of the dark andesitic rocks. This has been identified as albitization, with lesser amounts of epidote, chlorite, biotite, scapolite and calcite. This bleaching is plentiful at Pit 2, but K-feldspathization is also evident here. These orebodies can better be classified with pyrometasomatic deposits than with typical porphyry coppers. Their relationship to intrusives, the probably extensive metasomatic replacements, the evidence of pneumatolytic activity, the formation and redistribution of magnetite, and the irregular distribution of mineralization are all characteristic of this class. Deep-seated faults probably acted as channelways for mineralization; fracturing, faulting and rock contacts influenced ore localization in detail."

Jan 1, 1973

"Canada Centre for Mineral and Energy Technology (CANMET)Natural Resources CanadaMining and Mineral Sciences LaboratoriesA. Address and Contact Information555 Booth StreetOttawa, Ontario, Canada, KIA OGlWebsite: http://www.nrcan.gc.ca/Contact: Philippe Dauphin, Manager, Business DevelopmentTel.: (613) 947-0798Fax: (613) 947-0984E-mail: pdauphin@NRCan.gc.caB. Type and Size of FacilityScope of facilitiesCrushing from minus 4 in. to 10 mesh; grinding - rod, ball, vibration, SAG and impact mills; classification- screening, cycloning, mechanical, hydraulic and dry centrifugal classifiers; froth flotation - automated, column, and frothless flotation; gravity separation- wet and dry; magnetic separation - high gradient, high and low intensity, wet and dry; electrostatic separation; heavy-media separation; calcining; cyanidation; thickening; filtration; drying - fluid bed and freeze drying; pelletizing; microwave.SpecialtiesMineral beneficiation research and development; flotation of sulphides - flowsheet improvement, selectivity, reagent selection; novel flotation techniques; analysis of thiosalts formation; use of mineral processing techniques for recycling.Specialized equipmentHigh gradient magnetic separation, Denver XRF on-stream analyzer, automated flotation cell.Complementary support servicesElectron microprobe; SEM; STEM; X-ray diffraction; particle size analyzer; mineralogical and analytical chemistry services; physical chemistry; hydrometallurgy; pyrometallurgy; engineering and economic evaluation; mechanical shops; technical information services and library integrated with the National Library System of the National Research Council."

Jan 1, 2000

By J. Nalaskowski

A study of the interfacial properties of the basal plane and the edge surfaces of talc is described in this paper. The isoelectric point measured at the two different crystallographic planes by the streaming potential method was found to be similar and exists at about pH 3.0. In the case of the edge surface the zeta potential increases at higher pH values which can be attributed to the hydration of magnesium ions at the edge surface. The atomic force microscopy (AFM) colloidal probe technique was used to measure interaction forces. For such experiments a 20 um talc particle was attached to the AFM cantilever and forces between the edge of the talc particle and two different crystallographic planes of talc were measured at various pH values. These measurements, while being qualitative due to the poorly characterized contact area, show differences between the properties of the base plane and edge of the talc and correspond to the results from streaming potential measurements. Finally, the differences in the hydration of the basal plane and the edge of talc are revealed from molecular dynamics (MD) simulations. The basal plane of the talc is much less hydrated than the edge, as can be seen from the water density distribution functions, which correlate quite well with the contact angle measurements at the basal plane surface and the edge surface of the talc sample.

Jan 1, 2006

By M. Reda

Erosion corrosion is acceleration in the rate of corrosion attack in metal due to the relative motion of a corrosive fluid and a metal surface [1]. The increased turbulence caused by pitting on the internal surfaces of a tube can result in rapidly increasing erosion rates and eventually a leak [2]. Engineers and scientists in different disciplines have worked for many years on methods of complete protection from flow induced corrosion or partially reducing corrosion of this type, and they have proposed or applied different countermeasures [2]. The accident at the Surry-2 nuclear power plant (USA) and other similar incidents have once again disturbed the scientific-technical community. This has forced the plant operating personnel and the management to undertake wide-ranging measures in order to discover on time, assess, and monitor such cases. In these extreme cases, protective coating and even metallic bulk material coating (the substrate itself) may suffer considerably from mechanically induced damage [2]. At high velocities, the "leaching out" dissolution reaction of particular, for example, steel elements at the solid-liquid interface become the rate determining step. One practical example for the difference between erosion corrosion and flow induced corrosion is the famous steam eruption from a Japanese [3, 4] nuclear power plant cooling system at the pressurized water reactor (PWR), turbine and in the condenser-steam generator connecting pipe. The rupture occurred in the carbon steel pipe connecting the condenser and steam generator. The damage occurred in the easily eroded/corroded carbon steel at a vulnerable location downstream of an orifice plate, In general, when there is significant reduction in pipe thickness through erosion/corrosion, distinctive patterns are visible, but those patterns were not observed in this case, Thus one can speculate that another phenomenon is possibly controlling, Fluid flow within pipes reduces the pipe thickness leading to an eventual rupture, The thickness reduction mechanism is erosion/corrosion, One example is "cavitations corrosion", Erosion and corrosion occur at the same time, and it is difficult to determine which one is dominant, Therefore, the term, "erosion/corrosion," is used [5]. In the atomic energy field, the terms "Flow Accelerated Corrosion" and "Flow Induced Corrosion" are also used. It is the purpose here to show that during flow induced corrosion a different mechanism may possibly be operating and in some cases it can be different from the well known erosion corrosion. Another example is fretting failures in early Canadian nuclear steam generators which was thought to be due to excessive vibration caused by high.

Jan 1, 2010

By J. Bouchard, A. Desbiens, M. Maldonado, R. del Villar

ABSTRACT: Despite many years of practical applications in mineral processing plants, the potential of column flotation has still not been fully exploited. The challenge in measuring some key variables is certainly an important contributing factor to this situation. Reliable online measurement of varibles, such as the froth depth, bias, gas hold-up, frother concentration, bubble surface area flux, and bubble size distribution, provides opportunities for the application of various advanced control strategies and real-time optimization based on an economic criterion. For several years, Université Laval’sLaboratoire d’observation et d’optimisation des procédés researchers have been working on these opportunities. This paper describes the most recent advances and current research trends.

Jan 1, 2011

By D. Song

In this paper, the differential equations governing the mass transport and the electrochemical reaction in a cathode catalyst layer of polymer electrolyte membrane fuel cells are solved based on the polynomial series expansion method. Explicit expressions for the polarization curve as well as for the distributions of oxygen, current density and overpotential are obtained when a quadratic, cubic or quartic polynomial is employed to approximate the oxygen concentration distribution. These kinds of explicit solutions are desirable for MEA design and diagnosis purposes. The comparison between the conventional numerical approach and the explicit solution approach proposed here shows that satisfactory accuracy can be reached by the first four terms of the polynomial series. The effect of the catalyst layer thickness on the accuracy of the obtained explicit polynomial solutions is also discussed.

Jan 1, 2005

By M. T. Shehata, R. W. Revie, M. Elboujdaini

Environmentally assisted cracks in linepipe steels are initiated either as a result of stresses in combination with environmental effects, as in stress corrosion cracking (SCC), or as a result of trapped hydrogen in the steel, as in hydrogen-induced cracking (HIC). To understand better the mechanism of the crack initiation process, key metallurgical and environmental elements that can affect the cracking phenomena were investigated and are reviewed in this paper. The complexity of both cracking phenomena results from the dependence of SCC and HIC on multiple metallurgical, mechanical, and environmental parameters that may all influence both crack initiation and propagation; e.g., composition, microstructure and non-metallic inclusions in the steel, applied stress, water chemistry in the field, and ionic concentrations in the groundwater near the pipe surface to name a few for SCC. In addition, for HIC phenomena, one can add the concentration of H2S in the fluids transported in the pipe as well as concentration of CO2, pH, etc. In this paper, cracking of linepipe steels is analyzed critically, with particular attention to the crack initiation process. The paper is divided into two parts: The first part covers SCC and the second covers HIC.

Jan 1, 2005

By Jonathan Matthews

Efficient and effective management of mine tailings is essential for continued successful development of Alberta?s vast oil sands resources. Syncrude Canada Ltd. continues to research novel tailings management techniques in an effort to improve production efficiency and environmental sustainability. During the summer months of 2001, Syncrude Canada Ltd., in collaboration with members of the Canadian Oil Sands Network for Research and Development (CONRAD), conducted field-scale trials of thickened tailings technology at Syncrude?s Aurora mine, north of Fort McMurray, Alberta. This paper provides an overview of the test program including discussion of objectives, test configuration, and program observations. 0Data collected during the field trial indicate that substantial swings in feed slurry composition challenge effective thickener operation. When coarse mineral solids dominated slurry composition, thickener rake torque rose to unmanageable levels. It was determined that the end-of-pipe depositional characteristics of thickened oil sands slurry were generally consistent with present understanding of oil sands tailings slurries. After shear, thickener underflow product exhibited very shallow beach angles and a limited capacity to keep coarser particles in suspension indicating that stacking of ?paste-like? thickener underflow product from a conventional thickener is not practical in an oil sands setting unless process adjustments can be made to increase the underflow density and/or preserve the initial high yield stress of the underflow during transport and deposition. These technical challenges notwithstanding, Thickened Tailings technology offers considerable promise for recovery of warm water from oil sands process tailings.

May 1, 2003

By J. M. Janssens, Van Quach Tinh, M. Ruel, R. Leblanc

"Microscopic studies of peat moss indicate a highly porous material. In view of using this natural product as an adsorbing agent for the treatment of polluted water, studies of its adsorbing power for beef extract and alkyl benzene sulphonate solution were determined. The effects of time of contact, particle size, concentration of adsorbent and concentration of pollutant were studied. In the case of beef extract, there is a COD reduction of around 27 per cent; in the case of the alkyl benzene sulphonate, the percentage reduction varied from 72 to 95 per cent. A water treatment plant based on the adsorbing power of peat moss with simultaneous recuperation of the pollutant is proposed."

Jan 1, 1971

By G. E. Murray

Introduction The development of the method for recovering zinc from lead blast-furnace slags at Trail is interesting and important in the history of both lead and zinc metallurgy. Many efforts have been made in the past, particularly in Germany, to make economic recovery of zinc from slag. The Pape process on Oker slags was successful and is being worked at the present time. More recently the Waelz process has come to the fore. One effort at Cockle Creek, Australia is of special interest in view of subsequent developments. This was re-ported in detail by Guy Courtney in 1920(1). It deserves mention as it shows how, as in many other instances in the metallurgy of lead and zinc, important pioneering work has been done in Australia. These experiments, started over 25 years ago, comprised reduction with coke, powdered coal, and eletrothermically in carbon-lined furnaces. The so-called slag eye furnace, which volatilised the metals from a blast furnace running with a hot top, was also investigated.

Jan 1, 1933

By M. S. Badollet

"DURING the past five years, production of asbestos fibers has increased in all countries that list asbestos as one of their mineral resources. Despite the many small mines that have been opened in Canada, United States, Mexico, South America, Italy, South Africa, Australia, Yugoslavia, and Rhodesia, the supply still does not meet the demand. It is estimated that total 1952 world production of asbestos fibers of all varieties approximated 1,600,000 tons, with Canada supplying 966,382 tons (I), or 60 per cent of all fiber mined.Asbestos fiber brokers continually are offering odd-lot samples of chrysotile, amosite, crocidolite, tremolite, and anthophyllite fibers to manufacturers, •quoting fantastic prices for tonnages •varying from just a few to 50 or more in a month. In many cases, the samples are not properly graded and contain quantities of rock impurities and finely ground dust.When vendors submit samples of asbestos fibers, the manufacturer should consider• them in terms of price, quality, quantity, and as possible substitutes for fibers currently used in his products.Grading of these odd-lot fibers in most cases has been poorly done, with resultant non-uniform fiber lengths. In some instances, a number of miscellaneous lots of fibers have been .blended for sale. This blending produces a fiber that is difficult for the manufacturer to accept as a substitute for the well-standardized Canadian fibers."

Jan 1, 1953

By S. Mathieu, R. Mennillod-Blondin, P. Cousin, N. Valle, H. Bouzahzah, P. Marion

The gold deposit of the Lapa mine has a complex mineralogical gold state with coarse and fine native gold, aurostibite and submicroscopic gold within arsenopyrite. A specific mineralogical characterization of the refractory fraction was conducted combining various techniques such as optical microscopy, electron microscopy, electron microprobe and secondary ion mass spectrometry. In parallel, the mineral processing behaviour and the recovery of the refractory gold were studied by pressure oxidation and cyanide leaching. This paper presents the mineralogical methodology developed to characterize the refractory gold distribution within arsenopyrite. These results are presented and interpreted in order to plot gold recovery versus sulphide oxidation. The comparison of the metallurgical behaviour yields predicted from the mineralogical data and the one calculated from leaching tests shows a good agreement and allows mineralogical explanations of the gold metallurgical behaviour.

Jan 1, 2011

By E. Eccleston, E. Gardner, F. Letarte, R. Schonewille

"In 2005, after nearly a decade of process development and feasibility work, the commercialization of the Falconbridge Nickel Smelting Technology (NST) began in earnest with the design and construction of a grassroots ferronickel plant at Koniambo Nickel in New Caledonia. The NST process was developed as an alternative to the conventional Rotary Kiln-Electric Furnace (RKEF) process for production of ferronickel from saprolitic nickel laterite ores. The NST process promised environmental and energy efficiency advantages over the conventional route. A key step of the NST process involves fluidized bed pre-reduction of calcined laterite ore using direct injection of pulverized coal as the reductant. Two parallel fluidized bed reduction roasters (FBRs) were installed at Koniambo Nickel, each designed for a maximum capacity of 4,200 MTPD of calcined nickel laterite ore. This paper describes the process development and scale-up of the fluidized bed pre-reduction process, the design challenges associated with the prototype commercial units, and the current status of the FBR operation at Konaimbo.INTRODUCTION In the mid-1990s, Falconbridge began to develop a new flowsheet for production of ferronickel from nickel laterite ores. The process that developed came to be known as the Falconbridge Nickel Smelting Technology (NST). The flowsheet, which is particularly appropriate for saprolitic ores, involves several major unit operations, including: drying in a hammer mill-flash dryer, calcination and preheating in a flash calciner, pre-reduction in a fluidized bed reactor, and smelting in a DC arc furnace to produce the ferronickel product. This paper focuses on the fluidized bed pre-reduction step of the process and provides an overview of the process chemistry, laboratory and pilot plant development work, scale-up and commercialization of the pre-reduction step, and the results obtained in the prototype commercial units."

Jan 1, 2017

By Marcin Ziemski

This paper reports on an energy efficiency analysis completed as part of a research project looking at energy reduction opportunities in minerals processing operations. The plant discussed is a gold production facility owned by Newmont Gold in the Tanami region of central Australia. Due to its remote location, lack of nearby gas pipeline or power grid, the operation has been completely dependent on diesel fuel for its electricity generation and transport needs. The mine and processing plant use electrical power at a rate of 12MW to 18MW, resulting in a monthly electricity cost of over US$1.5M. The high cost of diesel combined with an impending power generation capacity shortage drove Newmont to undertake the energy efficiency study. An energy audit of the plant showed opportunities for significant energy savings through the strategic use of waste heat, fuel replacement alternatives and renewable energy sources.

May 1, 2007