Valorização do granito de Pedras Salgadas como rocha ornamental
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2019-02-15
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A caraterização da homogeneidade textural, não revela a presença de elementos que contribuam para heterogeneidades texturais e que comprometam a exploração ou afetem o rendimento das pedreiras em laboração. A variação cromática entre as pedreiras deste granito, tem sido identificada pelas diferentes empresas transformadoras, procurando-se neste trabalho avaliar estas diferenças. Foram analisadas chapas, com acabamento polido, provenientes de diferentes pedreiras e analisados os parâmetros L*, a* e b* para cada chapa. Quando comparados os valores, é possível separar as pedreiras em dois grupos, um que apresenta granito com coloração mais escura e outro que apresenta uma cor mais clara. O levantamento da fraturação e espaçamento de fraturas foi efetuado em dois locais distintos, numa área virgem e em pedreiras ativas. Este levantamento permite o cálculo de vários índices de fraturação e assim determinar a aptidão da área virgem para fornecer blocos comerciais. A nova área apresenta potencialidades para a instalação de uma nova pedreira. O cálculo do volume teórico possível de ser extraído em frentes de trabalho foi determinado utilizando o programa 3D_BlockExpert. A utilização desta ferramenta permite definir o tamanho e forma dos blocos a extrair e contribuir para aumentar o rendimento das pedreiras. Foi possível a criação de um novo acabamento superficial à base de óxidos de ferro, aplicado em condições ambientais específicas. Esta solução pode ser aplicada no granito de Pedras Salgadas, mas também em outras rochas granitoides.
The aim of this work was the valorisation of Pedras Salgadas granite as ornamental stone. For this purpose the characterization of the textural homogeneity, the systematic study of joints and research of a new surface finish were done. Textural evaluation does not reveal the presence of heterogeneities compromising the exploitation or affecting the quarries yield. This study aimed to evaluate the chromatic variation among quarries as identified by different processing companies. Chromatic parameters L*, a* and b* were analysed in polished slabs from different quarries. Two different groups stand out from the results, one with a darker granite and other with a whitish coloration. The evaluation of joint sets and joint spacing was carried out in two different locations, a virgin area and active quarries. After the survey several fracture indexes were computed and the suitability of the virgin area to provide commercial blocks was assessed. The new area shows potential for the installation of a new quarry. The theoretical quarry yield was evaluated using the program 3D_BlockExpert. This tool allows to define the size and shape of the blocks to extract and contributes to increase the quarry production. It was possible to create a new surface finish based on iron oxides, applied under specific environmental conditions. This solution can be applied in Pedras Salgadas granite and other whitish granitoid rocks as well.
The aim of this work was the valorisation of Pedras Salgadas granite as ornamental stone. For this purpose the characterization of the textural homogeneity, the systematic study of joints and research of a new surface finish were done. Textural evaluation does not reveal the presence of heterogeneities compromising the exploitation or affecting the quarries yield. This study aimed to evaluate the chromatic variation among quarries as identified by different processing companies. Chromatic parameters L*, a* and b* were analysed in polished slabs from different quarries. Two different groups stand out from the results, one with a darker granite and other with a whitish coloration. The evaluation of joint sets and joint spacing was carried out in two different locations, a virgin area and active quarries. After the survey several fracture indexes were computed and the suitability of the virgin area to provide commercial blocks was assessed. The new area shows potential for the installation of a new quarry. The theoretical quarry yield was evaluated using the program 3D_BlockExpert. This tool allows to define the size and shape of the blocks to extract and contributes to increase the quarry production. It was possible to create a new surface finish based on iron oxides, applied under specific environmental conditions. This solution can be applied in Pedras Salgadas granite and other whitish granitoid rocks as well.
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Dissertação de Mestrado em Geociências Aplicadas
Palavras-chave
Rocha ornamental , Granito , Heterogeneidades , Fraturação , Coloração