1,720,963 research outputs found
Keynote Paper: Some Perspectives on Implications of Top Globally Ranked Factors Affecting Mining on the Future of Mine Planning
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120 years of excellence in service to Mining.
Get PDFThis summary was prepared by Sally Braham on behalf of: Prof Cuthbert Musingwini, Head of the School of Mining Engineering at the University of the Witwatersrand.The Wits School of Mining Engineering, which is celebrating 120 years of service to the
mining industry, is the seed from which the University of the Witwatersrand grew, and is now the largest mining school in the English-speaking world.MvdH201
A Probabilistic Block Economic Value Calculation Method for Use in Stope Designs under Uncertainty
No full textUncertainty is intrinsic to mine design and planning and introduces risk into the process. Nonetheless, most mine design and planning processes have historically been undertaken as deterministic processes, often resulting in unrealistic mine designs and plans which potentially lead to the destruction of shareholder value. This paper presents a probabilistic block economic value (BEV) calculation approach to minimise the shortcoming of using deterministic BEVs, and evaluates the impact of uncertainty on stope designs. The probabilistic BEV calculation approach was applied to a synthetic geological block model of a gold mineral deposit. The uncertainty associated with BEV input parameters was simulated using Monte Carlo simulation to create equally probable economic orebody models which were then used to create stope designs at different levels of risk. The probabilistic approach generated 20% to 53% higher net present values (NPVs) compared to the deterministic approach within 30% to 70% probability range. This indicates that, for the case study deposit, blocks with approximately 30% to 70% probability of having positive BEVs are the ones that should be used for mine design and planning. The results demonstrate that incorporating uncertainty early in underground mine design and planning potentially creates higher-value stopes
Insights and future research directions from a bibliometricmapping of studies in stope layout optimisation
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Optimisation of Three-Dimensional Stope Layouts Using a Dual Interchange Algorithm for Improved Value Creation
No full textOptimisation of three-dimensional (3D) underground stope layouts is a computationally complex process since it involves the modelling of many variables and constraints. As the number of variables and constraints increases to reflect the actual mining practice, the model complexity and solution time tend to increase exponentially, making the optimisation problem intractable. Metaheuristic approaches have therefore been used predominantly to solve the problem, but do not guarantee ‘true’ optimality. To minimise this limitation, a dual interchange algorithm (DIA) was developed by combining the strengths of two metaheuristic generic algorithms, namely the particle swarm optimisation (PSO) and genetic algorithm (GA). The DIA performance was compared to that of the Mineable Shape Optimizer (MSO) on four different design scenarios. The DIA generated stope layout economic values (SLEV) for three scenarios which were 0.3%, 3.4%, and 8.3% higher than for MSO under fixed and variable stope width conditions, while MSO produced a SLEV which was 9.7% higher than the DIA for a fixed stope width. This paper demonstrates that the DIA is a novel way of solving 3D optimisation of stope layouts under variable stope widths as encountered in actual mining practice
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