No description available.

Thesis (M. Phil.)--University of Hong Kong, 2009. / Includes bibliographical references (leaves 69-71). Also available in print.

Thesis (Professional Degree)--University of Missouri, School of Mines and Metallurgy, 1937. / The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed April 22, 2010) Includes bibliographical references (p. 52-58) and index (p. 59-60).

published_or_final_version / Mechanical Engineering / Master / Master of Philosophy

Working around conveyor belts is the cause of numerous accidents each year that are costly to the mining industry. Current safety training practices generally include the use of slide show presentations, lectures, videos, and paper material before sending each worker onto site with an experienced person for on-the-job task training. These training methods are passive in nature and do not allow for an actual realization of consequences resulting from ignoring safety practices during interaction between the employee and the environment. It is with this in mind that virtual reality (VR) is being proposed as an added effective method of safety training. In order to prove this hypothesis, a working VR prototype application of a mining environment has been developed. The application is designed in two modules. The first consists of an instructional based module, where the user is given all relevant information based on background research dealing with safety issues, hazard awareness, conveyor maintenance, and conveyor components and assemblies. The second module is a task-based training session that then tracks the user's performance as they complete assigned tasks. An evaluation scheme was performed on the prototype to determine the usability and usefulness and identify areas in need of improvement. First, industry professionals were presented the application in an informal setting where the types of information and overall concept were examined and perceived usefulness was discussed. Secondly, users, both novice and industry professionals, were asked to go through the prototype training application and rate their agreement with statements based on the user interface and usability of the application. Finally, subjective interviews were performed to record perceived benefits of the virtual reality application over typical training material. This final stage consists of using both industry professionals and novice experience individuals and documenting their perceptions of benefits and challenges of using both typical methods of training and the designed prototype. This document consists of an explanation of the research steps and papers that are published (or in press) detailing certain areas of the research, compiled findings, conclusions, and future research suggestions. / Master of Science

Os custos de produção de minério de ferro possuem variações de acordo com a especificidade de cada mina. Na fase mina, dois dos maiores custos de produção estão associados aos índices: distância média de transporte e a relação estéril minério. A implantação do projeto de múltiplas minas e correias transportadoras em Itabira visa diminuir os custos associados a estes dois indicadores. O método de alimentação da planta de beneficiamento oriundo de múltiplas minas foca em reduzir a relação estéril minério global do complexo e a implantação de correias transportadoras mitiga o aumento da distância média de transporte. O presente trabalho tem seu enfoque em uma proposta de lavra de múltiplas minas e de uma pilha de minério para alimentação de três diferentes usinas. Propõem-se um modelo de programação linear por metas que determinará a melhor alimentação das usinas, menor distância média de transporte e menor relação estéril minério. Este modelo de otimização foi elaborado utilizando o software LINGO com interface com EXCEL, e avalia cenários diversificados entre o transporte por caminhões fora de estrada e o transporte misto entre caminhões fora de estrada e transportadores de correia de longa distância. Os resultados apresentados mostram que o método de múltiplas minas é uma saída técnica e economicamente viável para melhor aproveitamento das jazidas do Complexo Minerador de Itabira, apresentando uma economia que varia de US$82M até US$118M dependendo do local de instalação das unidades de Britagem Semimóvel (BSMs). / Production costs of iron ore varies according to the specificity of each mine. In the mining phase, some of the largest operational costs are associated to the haulage distance and the stripping ratio. In this context, the implementation of the multiple mines project and the conveyor belts at the Itabira Complex Mines aims to optimize these two indicators. The multiple mines methodology focuses on reducing the overall stripping ratio of the complex, and the implementation of conveyor belts mitigates the increase of the haulage distance. Two mines and a stock pile are available to feed three different concentration plants. The goal is to achieve the best way to feed the plants considering the economic aspects. A linear goal programming model is proposed to determine the best iron ore mass feeding the plants from different mines, taking into account the least haulage distance and the smallest stripping ratio. This optimization model was developed using LINGO Software to interface with EXCEL and evaluate diversified scenarios. The results showed that the method of multiple mines is a technical and economically viable method for mine planning at the Itabira Complex.

Cette thèse porte sur l’étude du comportementdes bandes de convoyeurs soumisesà des contraintes mécanique, thermique et hydrique.La bande est constituée par un renforttextile multi-plis incorporé dans deux couchesde revêtement en caoutchouc. Le matériau dela bande en composite structural a été caractériséexpérimentalement à l'aide des essais mécaniqueset hydriques sur des éprouvettes normaliséesen composites avec et sans couche decaoutchouc. Des essais d’impact sont élaborésà fin d’identifier les différents modesd’endommagement à l’aide des observationsmicroscopiques.Une étude expérimentale est élaborée sur laméthode de réparation de la bande par collagede patchs internes en utilisant deux procédés decollage : la polymérisation à froid et la vulcanisationà chaud. Deux modèles analytiques unidimensionnelet bidirectionnel sont développéset confrontés aux modèles par éléments finispour étudier le comportement hygrothermomécaniquede la bande à l’aide des donnéesde caractérisation expérimentale. Les résultatsont montré que les performances de laméthode de réparation dépendent de différentsparamètres hygro-thermomécaniques et géométriques.Un outil d’aide à l’amélioration et à laconception en tenant compte de ces paramètresest enfin proposé. / This thesis deals with the study of themechanical behavior of a conveyor belt underhydrothermal effects. The structure that hasbeen studied consists of a 4 textile layers boundtogether by a thin rubber adhesive layer andcovered with the rubber cover. The beltcomposite structural was characterized usingstandard specimens with and without rubberlayers under tensile and ageing tests. Impacttests are developed to identify the differentdamage modes using microscopic observations..Experimental study of reparation method waselaborated using two processes: hotvulcanization and cold polymerization. Twoone-dimensional and bidirectional analyticmodels are developed and compared with finiteelement models to study the hygrothermomechanicalbehavior of the belt usingexperimental characterization parameters. Theresults showed that the performance ofreparation method of the belt depends ondifferent parameters. A tool for improvementand designing of the reparation is proposedtaking into account these parameters

Correias transportadoras têm sido utilizadas como um modo eficiente de transporte de materiais por diversos ramos da indústria. A vida útil desse equipamento é influenciada pelo desgaste natural ocasionado pelo uso excessivo e falhas, tais como rasgos, cortes e perfurações. Nesse trabalho, é proposto um método de identificação de falhas em correia transportadora por meio de processamento digital de imagens, combinadas com técnicas de escaneamento 3D a laser e aprendizado de máquinas (redes neurais e SVM (Support Vector Machine - Máquina de Vetores de Suporte)). A averiguação experimental foi efetuada em duas etapas: a primeira etapa inicia-se com a aquisição, o pré-processamento e a geração do banco de imagens; a segunda, com a extração e a classificação das amostras. O vetor de características foi submetido a dois classificadores: rede neural do tipo Perceptron Múltiplas Camadas (com 15 topologias candidatas) e um classificador SVM, variando sua função kernel: linear, quadrática, polinomial, gaussiano, RBF (Radial-Basis Function - Função de Base Radial) e MLP (Multilayer Perceptron – Perceptron Múltiplas Camadas). Os resultados experimentais mostram que a metodologia proposta obtém uma boa acurácia na estimação das falhas, mostrando-se promissora na tarefa de diagnosticar e classificar falhas em correias transportadoras. / Conveyor belts have been used as an efficient way of transporting materials by various industry branches. This equipment\'s lifespan is influenced by natural wear caused by overuse and flaws, such as tears, cuts, and perforations. This work proposes a method of identifying flaws in the conveyor belt using digital image processing, combined with 3D laser scanning techniques and machine learning (neural networks and SVM - Support Vector Machine). The experimental investigation has been carried out in two stages: the first stage begins with the acquisition, preprocessing, and generation of an image bank; the second, with the extraction and classification of the samples. The characteristic\'s vector has been submitted to two classifiers: Multi-Layer Perceptron neural network (with 15 candidate topologies) and an SVM classifier, varying its kernel function: linear, quadratic, polynomial, Gaussian, RBF (Radial-Basis Function) and MLP (Multilayer Perceptron). The experimental results show that the proposed methodology obtains a good accuracy in the failure estimation, being promising in the task of diagnosing and classifying flaws in conveyor belts.

Syftet med arbetet var att undersöka möjligheten för optimering av produktflödet. Företagets produkter transporteras på ett transportband till en gemensam process. Det nuvarande flödet till processen är inte optimerat vilket resulterar i att processen körs ineffektivt. Ackumulering av produkter innan processen ska därför undersökas som en lösning till problemet. Fyra olika ackumuleringsförslag har analyserats och jämförts: hängande bansystem, palleteringssystem, depalleteringssystem och kombination av bansystem och palleteringssystem. Förslagen har blivit bedömda och jämförda utifrån följande parametrar: yta, investeringskostnad, flexibilitet, arbetsbelastning, arbetsmiljö och tid. Hängande bansystem fick det högsta snittvärdet och valdes därför för fortsatt analys med stöd av simulering. Simuleringen gjordes i ExtendSim 7. Två simuleringsmodeller jämfördes, en med ackumulering av produkter i bansystem och en utan. Resultatet var att ackumulering av produkter kan ge en besparing på 16 procent i driftkostnader per år. Simulering av övriga förslag kan göras för att få en tydligare jämförelse mellan förslagen. Rekommendationen till företaget är att ackumulera produkter i ett bansystem. Det baseras på analys av jämförelsen. Analysen och diskussionen visar också att robothantering inte är en passande lösning på problemet, eftersom rörelserna skulle skaka om produkterna för mycket. En vidare undersökning av utformningen av bansystemet bör göras för att få fram den optimala utformningen. / The purpose of the work was to investigate possibilities for optimization of the material flow. The different products of the company are being transported by a conveyor belt to a common process. The current flow to the process is not optimized with the result that the process runs inefficiently. Accumulation of products before the process should therefore be investigated as a solution. Four different accumulating systems have been analyzed and compared: hanging conveyor belts, palletizing, depalletizing and a combination of conveyor belts and palletizing. The systems have been assessed and compared according to six parameters: area, investment cost, flexibility, work load, work environment and time. The hanging conveyor belt yielded the highest average score and was therefore chosen for further analysis with the support of simulation. The simulation was made in ExtendSim 7. Two simulation models were compared, one with accumulation of product in conveyor belts and one without. The result of the simulation part was that accumulation of product results in savings of running costs with 16 percent per year. To get a better comparison between the accumulation systems simulations of all systems can be done. The recommendation to the company is to accumulate products in a conveyor system. This is based on the analysis of the comparison. The analysis and discussion also shows that robot handling is not an appropriate solution to the problem, because the movements would shake the products too much. A further investigation of the layout should be done in order to find the optimal layout.

Os custos de produção de minério de ferro possuem variações de acordo com a especificidade de cada mina. Na fase mina, dois dos maiores custos de produção estão associados aos índices: distância média de transporte e a relação estéril minério. A implantação do projeto de múltiplas minas e correias transportadoras em Itabira visa diminuir os custos associados a estes dois indicadores. O método de alimentação da planta de beneficiamento oriundo de múltiplas minas foca em reduzir a relação estéril minério global do complexo e a implantação de correias transportadoras mitiga o aumento da distância média de transporte. O presente trabalho tem seu enfoque em uma proposta de lavra de múltiplas minas e de uma pilha de minério para alimentação de três diferentes usinas. Propõem-se um modelo de programação linear por metas que determinará a melhor alimentação das usinas, menor distância média de transporte e menor relação estéril minério. Este modelo de otimização foi elaborado utilizando o software LINGO com interface com EXCEL, e avalia cenários diversificados entre o transporte por caminhões fora de estrada e o transporte misto entre caminhões fora de estrada e transportadores de correia de longa distância. Os resultados apresentados mostram que o método de múltiplas minas é uma saída técnica e economicamente viável para melhor aproveitamento das jazidas do Complexo Minerador de Itabira, apresentando uma economia que varia de US$82M até US$118M dependendo do local de instalação das unidades de Britagem Semimóvel (BSMs). / Production costs of iron ore varies according to the specificity of each mine. In the mining phase, some of the largest operational costs are associated to the haulage distance and the stripping ratio. In this context, the implementation of the multiple mines project and the conveyor belts at the Itabira Complex Mines aims to optimize these two indicators. The multiple mines methodology focuses on reducing the overall stripping ratio of the complex, and the implementation of conveyor belts mitigates the increase of the haulage distance. Two mines and a stock pile are available to feed three different concentration plants. The goal is to achieve the best way to feed the plants considering the economic aspects. A linear goal programming model is proposed to determine the best iron ore mass feeding the plants from different mines, taking into account the least haulage distance and the smallest stripping ratio. This optimization model was developed using LINGO Software to interface with EXCEL and evaluate diversified scenarios. The results showed that the method of multiple mines is a technical and economically viable method for mine planning at the Itabira Complex.