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Controlo estatístico de processos aplicado à indústria mineira : exploração de carvão mineral na província de Tete em Moçambique
| Name: | Description: | Size: | Format: | |
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| 3.73 MB | Adobe PDF |
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Abstract(s)
O presente estudo apresenta uma revisão e aplicação de métodos de Controlo Estatístico de Processos na indústria mineira. A pesquisa incidiu no processamento e análise laboratoriais de qualidade do carvão mineral e foram definidas quatro (4) variáveis importantes que definem a qualidade do carvão térmico a ser fornecido ao cliente. A presença de algumas amostras com teores elevados de cinza, humidade e matérias volátil e, teores baixo de Carbono Fixo, comprometem o poder calorífico do carvão mineral. Trata-se de ocorrências provocadas por diferentes causas, causas estas que podem ser conhecidas ou não. O principal objectivo desta pesquisa é mostrar a utilidade dos gráficos de Controlo para monitorização da qualidade do carvão mineral.
Para atingir o objectivo preconizado, aplicou-se o Controlo Estatístico de Processo(CEP), através de gráficos de controlo do tipo Shewhart (X), Soma Acumulada (CUSUM) e Média Móvel Exponencialmente Ponderada (EWMA), para identificar as amostras que apresentavam alguma variabilidade e posteriormente submeter a uma avaliação para a identificação das causas e suas possíveis correções.
Verificou-se que dentre os três tipos de gráficos, com os gráficos de Soma Acumulada (CUSUM) e Média Móvel Exponencialmente Ponderada (EWMA) é possível verificar uma tendência de aumento ou diminuição das percentagens dos teores das variáveis analisadas. Dessa forma o estudo sugeriu que qualquer um dos gráficos analisados pode ser usado para a monitorização da qualidade do carvão mineral.
The present study presents a review and application of Statistical Process Control methods in the mining industry. The research is focused on the laboratory processing and analysis of coal quality and defined four (4) important variables that define the quality of thermal coal to be supplied to the customer. The presence of some samples with high levels of ash, moisture and volatile matter and low levels of fixed carbon, compromise the heating power of the mineral coal. These are occurrences caused by different sources, which can be known or not. The main objective of this research is to show the usefulness of control charts for quality monitoring of coal. In order to achieve this objective, Statistical Process Control was applied through Shewhart (X), Cumulative Sum (CUSUM) and Exponentially Weighted Average (EWMA) type control graphs to identify the samples that presented some variability and subsequently submitted to an evaluation for the identification of the causes and their possible corrections. It was verified that among the three types of graphs, with the Cumulative Sum (CUSUM) and Exponentially Weighted Average (EWMA) graphs, it is possible to verify a trend of increasing or decreasing on the percentages contents of the analyzed variables. Thus, the study suggested that any of the analyzed graphs can be used for the monitoring of coal quality.
The present study presents a review and application of Statistical Process Control methods in the mining industry. The research is focused on the laboratory processing and analysis of coal quality and defined four (4) important variables that define the quality of thermal coal to be supplied to the customer. The presence of some samples with high levels of ash, moisture and volatile matter and low levels of fixed carbon, compromise the heating power of the mineral coal. These are occurrences caused by different sources, which can be known or not. The main objective of this research is to show the usefulness of control charts for quality monitoring of coal. In order to achieve this objective, Statistical Process Control was applied through Shewhart (X), Cumulative Sum (CUSUM) and Exponentially Weighted Average (EWMA) type control graphs to identify the samples that presented some variability and subsequently submitted to an evaluation for the identification of the causes and their possible corrections. It was verified that among the three types of graphs, with the Cumulative Sum (CUSUM) and Exponentially Weighted Average (EWMA) graphs, it is possible to verify a trend of increasing or decreasing on the percentages contents of the analyzed variables. Thus, the study suggested that any of the analyzed graphs can be used for the monitoring of coal quality.
Description
Keywords
Indústria mineira Carvão mineral Controlo Estatístico de Processos (CEP) Métodos estatísticos Gráficos Moçambique Statistical Process Control Mining industry Charts/Control charts
Citation
Miguel, Belchior Coelho - Controlo estatístico de processos aplicado à indústria mineira [Em linha]: exploração de carvão mineral na província de Tete em Moçambique. Lisboa: [s.n.], 2017. 169 p.