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Over a thirty year period the HIsmelt process has been developed as an alternative to the traditional blast furnace for the production of pig iron. This process involves the injection of fine iron ore and non-coking coal particles into a molten iron bath though a number of wall lances. These jets induce substantial mixing and splashing of molten droplets into the top space of the vessel due to the substantial volume of gas generated within the bath. Control of heat transfer, reactions and the complex multiphase fluid dynamics is critical to successful operation of the process. Since inception computational fluid dynamics has played an important role in scale-up and process optimisation (Davis et al. 2003, Davis and Dry, 2012). A “Bath model” has been developed which focuses on the smelt-reduction processes occurring within the bath volume of the HIsmelt vessel (Stephens et al. 2011). As this model is a transient multi-component Eulerian-Eulerian model with Lagrangian particle tracking for the coal and ore particles, it requires a substantial computational effort. For this reason (and due to the large thermal inertia of the liquid bath) earlier versions of the model have been isothermal. Particles enter the molten iron bath at close to ambient temperature. Heating of both the particles and gas stream by the bath will require a finite time and cause local cooling around the particle jet. To investigate this effect the bath model has been extended to include convective heat transfer between the bath, gas and particles, and radiation within the gas cavity. This paper reports on the incorporation of thermal effects into the model and presents results showing their impact. ACKNOWLEDGMENTS. The authors would like to thank HIsmelt Corporation for permission to publish this work, and in particular Dr Rod Dry for his long-standing support and technical inputs to the modelling effort.

The industrial process for producing primary aluminium metal is the reduction of powdered alumina in a Hall-Héroult reduction cell. These cells operate at temperatures above 940 °C with a highly corrosive electrolyte making physical measurement of the process difficult or nearly impossible. Computational models of the electro-magnetic fields and heat transfer are widely used in industry to design cells. Only recently (Feng et al., 2010b, Witt et al., 2012) have detailed computational models of the molten liquid-gas bath become available. Alumina distribution within the cells is important for cell efficiency and preventing anode effects. Using the bath flow information and an assumption of uniform reduction, a single scalar transport equation has been used to track the time variation of alumina within cells (Feng et al., 2011). In this work the previous single species model is extended to include six chemical species and four chemical reactions. The reaction pathway developed for the model is that solid alumina particles are fed to the bath surface, where they mix and submerge into the liquid bath, and then undergo dissolution from solid particles to the liquid species Na2Al2O2F4. Within the bath Na2Al2O2F4 converts to Na2Al2OF6, which is involved in an oxidation reaction with carbon to produce carbon dioxide and AlF3 at the anode surface. At the metal pad a cathodic reaction occurs with AlF3 converting to aluminium metal. Species solubility rates are based on the work of Solheim et al. (1995). A CFD model of a single anode in a bubbly cryolite bath was built based on a corner anode from an industrial cell. Steady state bath flows were calculated and used to transport the six chemical species in the new bath chemistry model. Results were obtained for 20,000 seconds of real time for species distributions in the anode to cathode distance (ACD), change in mass of species in the bath with time, rates for the four reactions at locations in the bath and change in the species mass fraction with time at various locations during a feeding cycle. ACKNOWLEDGMENTS. The present work was supported by the project “Gas and Alumina Distribution and Transport” (GADT), financed by the Research Council of Norway and Hydro Primary Metal Technology. Permission to publish the results is gratefully acknowledged. The authors wish to acknowledge the valuable discussions and advice provided by Asbjorn Solheim on the electro-chemical reactions, rates and processes in aluminium reductions cells.

Velopharyngeal dysfunction (VPD) resulting from an adynamic or hypodynamic velopharynx is an unusual pathology that poses vexing management problems for the Cleft Palate team. Correction of VPD has the potential for airway compromise. Endoscopically, this pathology is recognized by a large velopharyngeal (VP) gap size, which demonstrates little or no dynamic activity of the posterior or lateral pharyngeal walls nor of the velum in response to speech tasks or connected speech. Because of a paucity of literature defining the entity, a retrospective review of 175 patients who were treated for VPD at our center was undertaken. Analysis of management failures revealed an unexpected concentration of patients with hypodynamic or paretic VP mechanisms as documented by nasendoscopic assessments. A subpopulation of 41 (23%) patients with this characteristic was studied to define the patients at risk, to determine etiologic factors, and to critique intervention outcome among various surgical and nonsurgical managements. Results showed that the phenomenon of VP hypodynamism occurred more frequently in patients with submucous cleft palate (p = .014) and with VPD in association with malformation syndromes (p = .009) than in patients in other diagnostic categories. Conversely, VPD not associated with clefting occurred with greater frequency in the nonhypodynamic group than in the hypodynamic group (p = .002). Composite (surgical and prosthetic) primary management failure occurred In 42%. Between one and three procedures were necessary to achieve an acceptable speech result. We present a management algorithm and provide data regarding realistic expectations for various treatment outcomes in patients with this complex disorder, which have not, to date, been previously described.

Highland Valley Copper (HVC), located in south-central British Columbia, 75 kilometres southwest of Kamloops, operates one of the world’s largest copper and molybdenum mines. This paper discusses the Highmont Tailings impoundment concerning its various steps toward final closure. After Highmont Mining ceased operations in 1984, it joined the partnership with HVC in 1988 and moved its concentrator to Lornex. Since then the Highmont tailings have been under care and maintenance and have slowly proceeded towards final closure. As we are now approaching the final phases, this paper explains the various steps taken to bring the Highmont tailings impoundment toward final closure.

Airborne multispectral imagery of Highland Valley Copper Mine, near Kamloops BC was acquired in July 2005, the fourth in a series of airborne remote sensing campaigns. A quantitative index of vegetation biomass (Normalized Difference Vegetation Index or NDVI) and multispectral classifications are now available for 2001, 2002, 2003 and 2005 for reclamation sites at Bethlehem, Trojan, Heustis and Highmont Tailings areas. Temporal trends can now be examined. The remote sensing data show that 2005 was a “green” year. Most vegetation, whether dense, moderate or sparse, was actively growing and green at the time of imaging. This is in contrast to 2003, which was unusually dry. The four-year time series indicates an overall increase in vegetation density and greenness since 2001, with the drought of 2003 having clear, short-term impacts on the vegetation. On a more local scale, the area along Trojan Dam and the area to the north and west of Bethlehem Tailings showed dramatic increases in vegetation in 2005. Local analyses of reclamation sites at Bethlehem Northeast and Heustis demonstrate the usefulness of imagery to supplement ground evaluation of individual sites. With boundary vectors for all reclamation sites, these analyses could be extended throughout the mine to assist in reclamation assessment.