A comprehensive copper stockpile leach model: background and parameter sensitivity

The design and development of a comprehensive computational model of a copper stockpile leach process is summarized. The computational fluid dynamic software framework PHYSICA+ and various phenomena were used to model transport phenomena, mineral reaction kinetics, bacterial effects, and heat, energy and acid balances for the overall leach process. In this paper, the performance of the model is investigated, in particular its sensitvity to particle size and ore permeability. A combination of literature and laboratory sources was used to parameterize the model. The simulation results from the leach model are compared with closely controlled column pilot scale tests. The main performance characteristics (e.g. copper recovery rate) predicted by the model compare reasonably well with the experimental data and clearly reflect the qualitiative behavior of the process in many respects. The model is used to provide a measure of the sensitivity of ore permeability on leach behavior, and simulation results are examined for several different particle size distributions.

Reflection is alive and well, but not what you think

More and more, Business and Management students (and those in other disciplines) are being asked to undertake written reflection upon their learning as part of assessed course-work. This paper examines this trend and explores the thinking behind it: why lecturers see reflection as valuable to students, whether they undertake reflection themselves, what theoretical underpinning they perceive as justifying and explaining their views. The results of a survey undertaken among Business and Management lecturers are reported, which appear to show that the most influential writer on the subject of reflection in learning – the one most frequently cited by the respondents – is David A. Kolb, author of the well-known Experiential Learning Theory (1984), and one of the moving forces behind experiential learning in general. His ideas have attracted a good deal of criticism, but are still current, having been suitably updated and defended, (2005). The paper critically re-examines Kolb’s Experiential Learning Theory, challenging its relevance to most of Higher Education, as characterised by Peter Jarvis in his useful table of learning situations as “formal and intended” (2004; 108). Other criticisms of Kolb’s Experiential Learning Theory are advanced that are entirely new. Returning to the survey, the papers discusses the reasons lecturers believe reflection is valuable to students and concludes that Kolb’s model, and others such as Schön’s (1987), fail to adequately explain or even identify them.