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Commercial SOFC systems will likely utilize hydrocarbons or hydrogen produced from hydrocarbon fuels and therefore will likely be exposed to sulfur impurities. Conducting-Atomic Force Microscopy (C-AFM) is a scanning probe microscopy technique which maps both sample topography and conductivity with tens of nanometers resolution. In Ni-YSZ, C-AFM measures the resistance of the metallic network at scanned locations, with the ability to differentiate between interconnected and isolated metallic particles. We have applied C-AFM to Ni-YSZ SOFC anode materials, with the goal of monitoring changes in the conductivity of the Ni anode network resulting from SOFC degradation processes, such as H2S poisoning.

Jan 1, 2005

By K. Miao, W. Mu, M. Sharma, A. Haas, N. Dogan

"The ever increasing demand for cleaner steels with low inclusion content has highlighted the limits of our current knowledge for controlling and predicting inclusion agglomeration and removal during liquid steel processing. Key knowledge gaps in this area result from the complex nature of the problems associated with measuring and visualizing the phenomena studied. Confocal scanning laser microscope (CSLM) allows for continuous in situ observation of micron-size samples in real time, at high resolution, under conditions relevant to the steelmaking process. This paper summarizes some of recent CSLM applications in our laboratory to illustrate the methods of analyzing transient behavior. The reaction between inclusions and slag is given as an example. The dissolution rate of calcium aluminate inclusions in CaO-SiO2-Al2O3 slags has been studied at elevated temperatures: 1500, 1550 and 1600°C as well as thermodynamic/kinetic analysis. It is found that total dissolution time decreased with increasing temperature. The rate limiting steps are discussed. It is shown that the diffusion through a product layer is responsible for dissolution at 1500°C. At higher temperature, dissolution is most likely controlled by both boundary layer diffusion and chemical reaction at the slag-inclusion interface. In this paper, the evidence for and against the theory will be critically examined and repercussions of the theory to steel refining processes will be discussed.INTRODUCTION Inclusion formation during liquid steel refining is an unavoidable consequence of current ladle steelmaking processes. The nature and quantity of the inclusions formed in steel is critical in steelmaking, as it affects both productivity through clogging, and downstream physical properties of the steel. It is therefore crucial to better understand and control the formation, agglomeration and dissolution behaviour of inclusions in a slag in order to improve the removability of inclusions from liquid steel. Most research (Sandhage & Yurek, 1988; Sandhage & Yurek, 1990a; Sandhuge & Yurek, 1990b; Sandhuge, 1991) relevant to the kinetics of inclusion removal has been obtained by using a technique where simulated inclusion material (ceramic rods) is dipped in slag and the dissolution rate is measured. While much has been learned using this approach, the difference in scale from bulk materials to inclusions is likely to have a significant bearing on the dissolution kinetics of inclusions in a slag and will certainly result in a very different influence of capillary effects. Further, the data obtained using an indirect (dip test) procedure relies on a comparison of the initial and final conditions of a sample rather than in-situ observation which can be achieved in a confocal microscope in real time."

Jan 1, 2017

By Jerry Ran

Many large underground mines using the open stoping method have changed their primary applications of consolidated rock fill (CRF) to paste or consolidated hydraulic fill due to considerations of demand in infrastructure and equipment, system reliability, backfill capacity and material sources. However, some smaller or even large mines still use or consider using CRF for backfill purpose due to factors such as capital expenditure, availability or suitability of other fill types or in some cases local regulatory requirements. As demands on CRF applications diminish among major mining companies, there is a lack of recent literature on application of CRF to open stoping in design and operation. There are several methods being used for fill strength design. Results from these methods have been successfully applied to paste or hydraulic fill. However, the design strength for CRF is much higher than that determined by use of these widely accepted methods. In operation, CRF preparation and placement have significant impacts on the quality of placed CRF and therefore the mining performance. This paper reviews the current fill design methods and their applications to open stoping with presentation of the bench marking data, presents fill failure cases and various CRF preparation and placement arrangements and discusses quality assurance and control programs.

Jun 1, 2012

By G. Molloy

The purpose of this paper is to demonstrate the value of applying continuous improvement, in particular 5S and standard work, in an underground environment. 5S and standard work are two aspects of Lean manufacturing that have been applied in many industries. At Vale Canada Limited, the focus is to first stabilize the process, commonly through the use of 5S, standard work and other continuous improvement techniques. In parallel with building an engaged workforce, these approaches aim to incrementally stabilize and improve a process. 5S is an employee-driven, systematic methodology to reduce waste in all its forms through attaining, maintaining, and improving workplace organization. Identified as a foundational part of any improvement process, 5S aims to remove wastes that impact on the overall efficiency of the area. Standard work is used to formulate a common approach to how tasks are carried out to ensure consistency. Standardization involves identifying, establishing, and following the best method. The aim is to eliminate the variation that can occur when there is not a pre-defined established standard. Demonstrating the value of 5S and standard work in an underground environment will be achieved by first understanding the overall concept of Operational Excellence and continuous improvement as practiced within our operations. The paper will then cover a real application of 5S and standard work within the underground environment at Thompson, Manitoba.

Aug 1, 2013

By Rex C. Bryan

An accurate and dependable ore reserve estimate is important to any mining company. It is also essential for development drilling and production planning to know about the distribution of the ore within the area to be mined. This paper will show that in the case of more variable deposits such as uranium, the use of geostatistics is superior to conventional techniques. Unlike conventional methods, geostatistics includes the importance of spatial orientation of measured variables. With the use of variograms in conjunction with kriging, a point or a block may be estimated along with its error of estimation. The existence of disequilibrium can create a severe problem in uranium 'ore reserve estimation, and mine and production planning. Disequilibrium can be simply defined as the ratio of chemical or assay values to gamma equivalent values calculated from the downhole geophysical gamma-ray logs. Various methods for adjusting for disequilibrium have been proposed. Most, however, have side stepped the consideration of disequilibrium itself being a regionalized phenomena; or its, relation to surrounding geology. This paper presents methods of incorporating both aspects. The East Dilts Pit at the Bear Creek Uranium Mine in Wyoming, has been used as a case study. Polygonal, triangular, and lognormal kriging and various disequilibrium adjusted methods, including multi-factor cokriging have been com- pared with the mining experience.

Jan 1, 1982

By J. L. Barton, R. A. Murray

"This paper looks at how Syncrude Canada Ltd. is utilizing the Conveyor Belt Monitoring technology developed and patented by the Australian CSIRO and licensed to Syncrude by Conveyor Belt Monitoring of North America, Inc. The technology involves magnetizing the steel cables in the conveyor belts and detecting the fields produced by breaks, gaps or cable ends using special sensors which feed the signals into a multi- channel recorder to provide permanent traces of the various events taking place in the steel cable belts.The data is analyzed and combined with existing belt audit programs, to assist in predicting belt life, change-out criteria and belt design, belt loading and construction. All of these applications of the CBM technology leads to better utilization of resources and forms an integral part of the conveying system reliability program."

Jan 1, 1992

The selection of the ore haulage system is one of the most crucial decisions made in the development of an underground mining project. The haulage system is, once selected, one of the components of a mine that defines its ability to respond to changes in mining inventory and the market conditions for its products. Over the last decade, in Australia at least, this selection process has largely centred on the debate over the merits of shaft and decline truck haulage. Little attention, if any, was given to the application of inclined conveyor haulage as a real alternative to the shaft and truck haulage. This is despite well established precedents for its application in the underground coal industry and some limited applications in underground metalliferous mines. This paper seeks to explore the case for the application of inclined conveyors as a legitimate ore haulage system for underground mines. The case for conveyor haulage is illustrated by an overview of the application of conveyors at some existing operations, and discussion of what conveyors have to offer as a mine haulage system and the issues that are associated with them. Material drawn from the feasibility studies for NewcrestÆs Ridgeway mine and Telfer Deeps Project is presented as case studies that considered selection of inclined conveyor haulage. The purpose of these case studies is to highlight the value of impartially approaching tasks of this type with a robust plan. This plan should be able to respond to issues identified as the task progresses towards the objective of finding the right solution for an ore haulage system.

Jan 1, 2005

By John G. Kuhm

INTRODUCTION The goal of any development drilling program is the drilling of the exact number of holes necessary to adequately determine grade and dimensions of an orebody, no more and no less. This cost of development drilling represents a large part of the total development budget. Any technique which eliminates unnecessary drilling costs produces beneficial results, both to the company and to the person who can claim the savings. This high development cost factor has produced a quantity of research to develop techniques, for efficient control of drilling programs. Recent mining literature is full of articles describing methods for measuring and increasing the effectiveness of these expensive projects. The method described in this paper was developed during the latter part of a major development drilling project at the Christmas Mine of Inspiration Consolidated Copper Company in Gila County, Arizona. It was used to test the need for drilling individual holes but could be expanded to control an entire project. This technique was used at Christmas as a practical means for evaluating adequacy of drilling on an individual hole basis, and it was possible to eliminate several previously approved holes. Application of this method involves an evaluation of geological conditions present and a good bit of common sense. Projects involving large disseminated, rather homogeneous orebodies of the porphyry-copper type would be the most likely candidate for application of the technique. Discontinuous orebodies would not be amenable to this technique. The method is based on the measurement of the linear correlation between the spatial distribution of two sets of data. The Pearson product-moment correlation coefficient is used. This is a standard statistic commonly used to measure linear correlation between two sets of data. The statistical significance of the correlation coefficient at a 95% confidence level is the main criterion for controlling the project. For purposes of reference we will call our technique the "correlation method" in this paper.

Jan 1, 1971

By J. Donald Graham, John G. Kuhn

The goal of any development drilling program is the drilling of the exact number of holes necessary to adequately determine grade and dimensions of an ore body, no more and no less. Any technique which eliminates unnecessary drilling costs produces beneficial results, both to the company and to the person who can claim the savings. The method for controlling development drilling programs to be described was developed during the latter part of a major development drilling project at the Christmas mine of Inspiration Consolidated Copper Co. in Gila County, Arizona. It was used to test the need for drilling individual holes but could be expanded to control an entire project. Application of this method involves an evaluation of geological conditions present and a good bit of common sense. Projects involving large disseminated, rather homogeneous ore bodies of the porphyry-copper type would be the most likely candidates for application of the technique. Discontinuous ore bodies would not be amenable. The method is based on the measurement of the linear correlation between the spatial distribution of two sets

Jan 1, 1973

By K. Dzieciol

The paper presents a study about three image correlation methods ?common cross-correlation, mutual information and phase-correlation ? applied to characterize microstructures reconstructed with X-ray tomography. It is shown that phase correlation is not only the fastest, but also the most sensitive method for detection of similar microstructure features, cavities in the present case. A new image correlation indicator is proposed, which takes into account both the phase shift and the amplitude of similar features in compared images. Some preprocessing aspects related to the tomographic reconstruction and filtering out of characteristic noise are also discussed.

Jan 1, 2009

By A. L. Labbe

IT Is well known that the Cottrell process is more easily applied to certain kinds of smoke than to others. The successful Cottrell installations are those treating smokes that carry dust of a mechanical nature; also smoke carrying fume dust that contains an excess of sulfuric acid over that required to combine with the oxides in the dust. But up to the present time the process has not reached a satisfactory economical basis of operation, in the treatment of smoke' containing basic dust. It is not impossible to make a smoke containing basic dust suitable for the process by. humidifying or acidifying. A number of Cottrell plants use these two methods of conditioning smoke previous to Cottrell treatment, which are quite successful, but the use of either results in expensive operation and a substantial loss in metals.. For these reasons, I would say that the baghouse process has not been replaced by the Cottrell process in the treatment of smelter basic smoke. Basic smoke must be given a. preliminary conditioning treatment because the dust is not a conductor of electricity; the water or acid treatment imparts some conductivity to the dust.. The rate at which dust is recovered depends on the proportional amount of power transmitted to the, treater and on the rate at which the smoke passes through; therefore to maintain a maximum constant amount of power across the electrodes of the treater, the same degree of conductivity should prevail, at all times between the surface of the electrodes. For all practical purposes, in the application of this process to lead and copper-smelter smoke, we can consider that the conductivity of the gases is a .constant. The variations in temperature of the smoke have a much greater effect on the solids than on the gases; the only instance where the temperature of the gases plays an important part in the process is at plants using humidifying: The temperature does not affect the conductivity of mechanical dust because such dust has natural conductive properties. However, in the case of smoke carrying acid-fume dust, where the conductivity is imparted to the dust particles by coming into contact with the acid fumes, the temperature is of importance.

Jan 8, 1925

By G. Glinski, K. A. Pericleous

"Recent advances in new computational modelling techniques such as Lattice-Boltzmann and Dissipative Particle methods offer the prospect of simulating complex fluids such as colloidal and dense suspensions in industrial processes. They are referred to as mesoscopic methods since they lie between molecular dynamics at a microscopic atomistic scale «lO-9m) and traditional macroscopic CFD methods (> 1O-2m). The models behave like a 'coarse-grained' gas consisting of fictitious interacting particles, which are much larger than the real molecules of the actual fluid they represent. Inter-particle forces are set so that the collisions collectively mimic the phenomenological transport properties and flow of the underlying fluid at a macroscopic scale.Much of the developmental work to date has focused on laying theoretical foundations based on thermodynamic and kinetic theory. Successful applications include predictions of macroscopic transport properties of complex fluids and flows in porous media and filters. With the constant increase in computational power, these mesoscopic methods are now sufficiently developed to determine their suitability to simulate complex fluid flows in real industrial processes. This work describes the application of meso scopic methods to the stencil printing of solder pastes in the assembly of electronic components. The aim of this work is to assess the ability of these methods to study the transport mechanisms of individual solder particles suspended in the flux solvent as they enter and fill the micro-apertures of a stencil. This paper demonstrates the coupling of such mesoscopic methods to continuum CFD methods to predict the flow of dense suspensions (i.e. solder paste) in industrial processes."

Jan 1, 2001

By T Guiliani, F Ottuonye

Explosives casting is gaining increasing popularity as an overburden removal method in strip mining because the coats of using explosives to cast a percentage of the overburden to the spoil are lower than the costs of using stripping shovels or draglines to do all the overburden removal. This is due to the rising capital and operating costs of draglines and shovels.

Jan 1, 1989

By Bruce B. Redpath

Single-charge cratering tests can provide a direct measure of the powder factor necessary for achieving a desired effect in conventional blasting. If a desired blast effect, such as fragmentation or mound velocity, is produced by a single point-charge at a particular scaled depth of burial, then the cube of the reciprocal of that scaled depth is the appropriate powder factor for duplicating the effect in a conventional array of blast holes. Scaling formulas are presented that provide a link between point-, line- and plane-charge geometries, and which can be Apparent crater used for blast design. Mound and burden velocities from several sources are compared and several examples of blast design are given.

Jan 1, 1977

By Yaniuk DW

The sampling of non-ferrous concentrates from trucks and trains has long been carried out either manually or by automatic spears. Very little use has been made of conventional sampling systems for sampling concentrates at transfer points, or cross-belt samplers for sampling from the belt as the concentrate moves along the conveyor.Due to the high value of base metal concentrates and the often extremely heterogeneous nature of the material it is imperative that the sampling procedures adopted are accurate and precise. The basic principle that all particles in the stream have an equal opportunity to be included in the final sample is not fulfilled by accepted traditional concentrate sampling procedures such as the spearing of wagons, trucks or streams. This may lead to significant bias being introduced into the final sample.Consequently, the application of correct sampling procedures, either with conventional cross-stream samplers or the newer cross-belt samplers, is of prime importance.SGS Australia has recently installed a number of cross-belt samplers for the sampling of base metal concentrates both in Australia and overseas. The application of these samplers will be discussed with emphasis on the benefits of their use.

Jan 1, 1976

By M Fylak, R Wenda

Advanced preparation techniques open new ways for SEM and X-ray diffraction (XRD) investigations on hydrating cementitious systems. In this paper the early time hydration of Portland cement is studied with advanced cryo scanning electron microscopy techniques in combination with in situ X-ray diffraction and heat-flow calorimetry. The application of preparation techniques and analytical methods to Portland cement hydration are presented and discussed. Some aspects of hydration reactions are focused. The reaction products of the first minutes, changes in ettringite morphology, AFm formation during the deceleration period and the visualisation of C-S-H microstructures were special points of interest. X-ray diffraction analyses and Cryo-SEM images gave essential information about phase development, reaction kinetics, microstructure and morphology of hydration products. Portlandite, AFt and AFm phases were detected by in situ XRD. Cryo-SEM analyses enabled high resolution imaging and EDX-analyses of cement particles and reaction products. The results of the different analytical methods were compared to obtain detailed information about crystallisation processes and microstructural development during the first three days of Portland cement hydration.

Jan 1, 2008

By G. H. Kennedy

CYCLONE thickeners are "hydraulic centrifuges" designed either to produce a maximum practical separation between the water and solids of a feed slurry or to classify the slurry solids according to particle settling rate. The possibilities of utilizing the thickener to "close" plant water circuits have been investigated.

Jan 3, 1951

By Ishijima Y, Goto T

Displacement Discontinuity Method (DDM), which was originally developed by Crouch,S.L., is a powerful tool to calculate mechanical disturbances due to tabular excavations. Three topics on DDM applications to strata control problems in Japanese deep coal mines are described. First, is numerical simulation of microseismicity induced by longwall mining in Horonai Coal Mine. Microseismicity in the mine had been monitored by a mine-wide seismic ar- ray. Location of microseismic events and in- tensity of seismicity were well simulated. In the simulation procedure based on DDM, first, zones where a failure condition is satisfied by the advance of mining are detected. Then, the seismic moments, which indicate the inten- sity of seismicity, at the failure zones are evaluated. Second, is prediction of the shaft damage due to mining in Sumitomo Akabira Colliery. In this mine, the limit angle of the shaft pillar was changed from 600 to 800 to increase the amount of minable coal volume without increas- ing mining depth. Displacement of the shaft axis has been measured to assess the damage due to mining around the shaft pillar. In the calculation based on DDM, a fault intersecting the shaft and the ground surface are con- sidered. Observed and predicted displacement of the shaft axis agreed well.

Jan 1, 1992

By Yoshiaki Fujii

Displacement Discontinuity Method (DDM), which was originally developed by Crouch,S.L., is a powerful tool to calculate mechanical disturbances due to tabular excavations. Three topics on DDM applications to strata control problems in Japanese deep coal mines are described. First, is numerical simulation of microseismicity induced by longwall mining in Horonai Coal Mine. Microseismicity in the mine had been monitored by a mine-wide seismic array. Location of microseismic events and intensity of seismicity were well simulated. In the simulation procedure based on DDM, first, zones where a failure condition is satisfied by the advance of mining are detected. Then, the seismic moments, which indicate the intensity of seismicity, at the failure zones are evaluated. Second, is prediction of the shaft damage due to mining in Sumitomo Akabira Colliery. In this mine, the limit angle of the shaft pillar was changed from 600 to 800 to increase the amount of minable coal volume without increasing mining depth. Displacement of the shaft axis has been measured to assess the damage due to mining around the shaft pillar. In the calculation based on DDM, a fault intersecting the shaft and the ground surface are considered. Observed and predicted displacement of the shaft axis agreed well. Third, is the roadway deformation in Taiheiyo Coal Mine. Attainable maximum stress for a roadway was calculated considering three faults intersecting the roadway. It was realized that the roadway's convergence is related to the calculated stress by simple equations.

Jan 1, 1992

By Andrew Neale, Len Anderson, Rob Perry

"P.T Freeport Indonesia's new SAG mill commenced operation in February 1995. The reclaim system consists of four apron feeders and a series of three conveyors. The feeders are used in various combinations and relative speeds to blend SAG mill feed. It was recognized during design of the control system that effective automatic control would require dead-time and gain compensation. The successful implementation of the Dahlin algorithm to provide variable dead-time and gain compensation is described and compared to Pl control.RésumeL'opération du nouveau SAG de P.T. Freeport Indonésie a commencé en Février 1995. Le système de réclamation du minerai comprend 4 alimentateurs à tablier et une série de 3 convoyeurs. Les alimentateurs sont utilisés dans une combinaison variée et à des vitesses relatives différentes pour mélanger l'alimentation du SAG. II a été reconnu pendant la conception du système du contrôle que le contrôle automatique demandera une compensation pour le temps de délai et le gain. L'implantation de l'algorithme de Dahlin a été un succès et ii est comparé avec le contrôle Pl.ResumenP.T. Freeport Indonesia inició la operación de un molino semi autogeno (SAG) en febrero de 1995. El mineral es alimentado desde cuatro alimentadores tipo apron feeders y una serie de correas transportadoras. Los alimentadores se utilizan en variadas combinaciones y velocidades para mezclar apropiadamente el mineral que alimenta al molino SAG. Durante el diseño del sistema de control se detectó que el control automático requería de un tiempo muerto y compensaci6n de ganancia. En este documento se describe la implementación del algoritmo de Dahlin, que ha sido exitosa y ha permitido proveer tiempos muertos variables y compensaci6n de ganancia. Ademas se hace una comparaci6n con el Pl de control."

Jan 1, 1996