scholarly journals Uncertainty assessment of spatial domain models in early stage mining projects – a review

2021 ◽  
pp. 104098
Author(s):  
Scott McManus ◽  
Azizur Rahman ◽  
Jacqueline Coombes ◽  
Ana Horta
2016 ◽  
Vol 42 (1) ◽  
pp. 2-25 ◽  
Author(s):  
Marco Autili ◽  
Antonia Bertolino ◽  
Guglielmo De Angelis ◽  
Davide Di Ruscio ◽  
Alessio Di Sandro
Keyword(s):  

Subject Prospects for consolidation in the mining sector. Significance The five-year bear market in mining equities has left a trail of casualties. Bankruptcies and distressed sales have been common in bulk commodities, especially in the North American coal sector and among iron ore juniors. Lower metal prices revealed defects in a range of complex gold mining projects, several of which had to fold for technical reasons. As the largest companies emerge from the market bottom with damaged balance sheets, industry consolidation has so far been subdued: mining merger and acquisition (M&A) activity hit a cyclical low in 2015. Impacts Nimble operators are accumulating prospective land positions and will sell them as proven development properties in the next cycle. Unincorporated partnerships will flourish among like-minded companies seeking to carve out a niche in the product market. Royalty businesses will prefer cash-flow-generating projects to early-stage opportunities with future optionality. High-yield financing, hitherto available to mid-sized miners, will remain hostage to broader risks affecting this sector. Reduction of political risk could reopen mining opportunities for partnerships in regions long closed for foreign investment, such as Iran.


2017 ◽  
Vol 10 (1) ◽  
Author(s):  
Xinhe Zhao

Two methodologies used in aircraft system developments are Model-Based Safety Analysis (MBSA), which assesses the safety risk associated with design in later stages, and Model-Based Systems Engineering (MBSE), a process that creates the domain models to help design a system. With the continuous growing use of both methodologies, it is inevitable that they will become linked to improve the design process from many aspects. This review identifies and proposes potential links for the integration of MBSA and MBSE by using the V-model of MBSA, thereby resulting in more effective design processes and reduced development costs. The paper addresses a general interpretation of the topic and supplementary case studies within the industry regarding both methodologies. Some benefits of the link between MBSA and MBSE include: utilisation of a wider range of analysis tools, automated communication of important definitions, consistency between both ends, and a potential improvement in confidence regarding design. As this is a preliminary proposal regarding the best approach for using MBSA in combination with MBSE, further research should be performed into the areas of formalized language, defining systems requirements for the usage of this approach, and relationships with the existing regulations and compliance needs. Deux méthodes utilisées dans le développement des avions sont l’Analyse de sécurité basée sur des modèles (ASBM), qui évalue les risques de sécurité associés avec la conceptualisation d’étapes antérieures, et l’Ingénierie des systèmes basée sur des modèles (ISBM), un processus qui crée des modèles de domaine pour concevoir un système. Avec l’utilisation croissante des deux méthodes, il est inévitable qu’elles seront liées pour améliorer le processus de conceptualisation de plusieurs aspects. Cette revue identifie et propose des liens potentiels qui pourraient intégrer l’ASBM et l’ISBM, en utilisant le model-V de MBSA, résultant ainsi en des processus de conceptualisation plus efficaces et des coûts de développement réduits. L’article adresse une interprétation générale du sujet et des études de cas supplémentaires dans l’industrie qui concernent les deux méthodes de développement. Certains des avantages du lien entre ASBM et ISBM incluent: l’utilisation d’une grande gamme d’outils d’analyse, la communication automatisée de dé nitions importantes de conceptualisation, la cohérence entre les deux extrémités, et une confiance améliorée dans la conceptualisation. Comme ceci est une proposition préliminaire concernant la meilleure approche pour combiner l’ASBM et l’ISBM, de plus amples recherches devraient être menées dans les domaines du langage formel, les exigences des systèmes pour utiliser cette approche, les relations avec les règlements actuels et les exigences pour la conformité. 


Author(s):  
L. Vacca-Galloway ◽  
Y.Q. Zhang ◽  
P. Bose ◽  
S.H. Zhang

The Wobbler mouse (wr) has been studied as a model for inherited human motoneuron diseases (MNDs). Using behavioral tests for forelimb power, walking, climbing, and the “clasp-like reflex” response, the progress of the MND can be categorized into early (Stage 1, age 21 days) and late (Stage 4, age 3 months) stages. Age-and sex-matched normal phenotype littermates (NFR/wr) were used as controls (Stage 0), as well as mice from two related wild-type mouse strains: NFR/N and a C57BI/6N. Using behavioral tests, we also detected pre-symptomatic Wobblers at postnatal ages 7 and 14 days. The mice were anesthetized and perfusion-fixed for immunocytochemical (ICC) of CGRP and ChAT in the spinal cord (C3 to C5).Using computerized morphomety (Vidas, Zeiss), the numbers of IR-CGRP labelled motoneurons were significantly lower in 14 day old Wobbler specimens compared with the controls (Fig. 1). The same trend was observed at 21 days (Stage 1) and 3 months (Stage 4). The IR-CGRP-containing motoneurons in the Wobbler specimens declined progressively with age.


Author(s):  
W. O. Saxton

Recent commercial microscopes with internal microprocessor control of all major functions have already demonstrated some of the benefits anticipated from such systems, such as continuous magnification, rotation-free diffraction and magnification, automatic recording of mutually registered focal series, and fewer control knobs. Complete automation of the focusing, stigmating and alignment of a high resolution microscope, allowing focal series to be recorded at preselected focus values as well, is still imminent rather than accomplished, however; some kind of image pick-up and analysis system, fed with the electron image via a TV camera, is clearly essential for this, but several alternative systems and algorithms are still being explored. This paper reviews the options critically in turn, and stresses the need to consider alignment and focusing at an early stage, and not merely as an optional extension to a basic proposal.


Author(s):  
C. S. Lin ◽  
W. A. Chiou ◽  
M. Meshii

The galvannealed steel sheets have received ever increased attention because of their excellent post-painting corrosion resistance and good weldability. However, its powdering and flaking tendency during press forming processes strongly impairs its performance. In order to optimize the properties of galvanneal coatings, it is critical to control the reaction rate between solid iron and molten zinc.In commercial galvannealing line, aluminum is added to zinc bath to retard the diffusion rate between iron and zinc by the formation of a thin layer of Al intermetallic compound on the surface of steel at initial hot-dip galvanizing. However, the form of this compound and its transformation are still speculated. In this paper, we report the direct observations of this compound and its transformation.The specimens were prepared in a hot-dip simulator in which the steel was galvanized in the zinc bath containing 0.14 wt% of Al at a temperature of 480 °C for 5 seconds and was quenched by liquid nitrogen.


Author(s):  
C. Vannuffel ◽  
C. Schiller ◽  
J. P. Chevalier

Recently, interest has focused on the epitaxy of GaAs on Si as a promising material for electronic applications, potentially for integration of optoelectronic devices on silicon wafers. The essential problem concerns the 4% misfit between the two materials, and this must be accommodated by a network of interfacial dislocations with the lowest number of threading dislocations. It is thus important to understand the detailed mechanism of the formation of this network, in order to eventually reduce the dislocation density at the top of the layers.MOVPE growth is carried out on slightly misoriented, (3.5°) from (001) towards , Si substrates. Here we report on the effect of this misorientation on the interfacial defects, at a very early stage of growth. Only the first stage, of the well-known two step growth process, is thus considered. Previously, we showed that full substrate coverage occured for GaAs thicknesses of 5 nm in contrast to MBE growth, where substantially greater thicknesses are required.


2006 ◽  
Vol 175 (4S) ◽  
pp. 514-514
Author(s):  
David G. McLeod ◽  
Oliver Sartor ◽  
Paul F. Schellhammer ◽  
Anthony V. D'Amico ◽  
Susan Halabi ◽  
...  

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