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Abstract(s)
A dissertação aborda a análise de estabilidade de cinco bancadas da mina de Aljustrel, especificamente dos jazigos de Feitais, do Moinho e da Estação, exploradas através do método de desmonte ‘Sublevel Stoping Bench & Fill’. A metodologia adotada inclui a pesquisa bibliográfica, o tratamento de dados geotécnicos e geomecânicos mineiros e aplicação de métodos observacionais e programas informáticos para previsão de
problemas durante a exploração e definição de soluções de estabilidade. No jazigo do Moinho, a análise foi realizada utilizando a técnica de amostragem linear em faces expostas do maciço rochoso. No jazigo da Estação, devido à falta de acessos mineiros, a análise baseou-se principalmente em sondagens executadas na proximidade. Por último, as bancadas do jazigo de Feitais foram estudadas através do método da
representatividade, sendo este mais eficiente apesar de menos detalhado. Com base nos levantamentos realizados foram aplicadas as classificações geomecânicas QSystem, RMR e GSI, cruciais à obtenção de parâmetros para análise comportamental e de estabilidade, com recurso a programas informáticos e ao método gráfico de Potvin, e proposta de sustimento. Conclui-se que todas as bancadas apresentam os hasteais instáveis, em função das dimensões e descontinuidades presentes, requerendo cabos como método de sustimento, à exceção da bancada transversal secundária devido à pasta de enchimento adjacente.
This dissertation deals with the stability analysis of five benches at the Aljustrel mine, specifically the Feitais, Moinho, and Estação deposits, exploited using the Sublevel Stoping Bench & Fill blasting method. The methodology adopted includes the bibliographic review, the mining geotechnical and geomechanical data processing, and the application of observational methods and software to predict problems during mining and define stability solutions. The analysis of the Moinho deposit was carried out using the scanline sampling technique on rock exposure surfaces. In the Estação deposit, due to the lack of mining accesses, the analysis was based mainly on boreholes carried out nearby. Finally, the benches in the Feitais deposit were studied using the representativeness method, which is more efficient despite being less detailed. The QSystem, RMR, and GSI geomechanical classifications were applied based on the fieldcollected data. These were crucial to obtaining behavioral and stability analysis parameters using software, Potvin's graphical method, and proposed support. It is concluded that all the benches have unstable shafts due to the dimensions and discontinuities present, requiring cables as a support method, except for the secondary cross bench due to the adjacent paste fill.
This dissertation deals with the stability analysis of five benches at the Aljustrel mine, specifically the Feitais, Moinho, and Estação deposits, exploited using the Sublevel Stoping Bench & Fill blasting method. The methodology adopted includes the bibliographic review, the mining geotechnical and geomechanical data processing, and the application of observational methods and software to predict problems during mining and define stability solutions. The analysis of the Moinho deposit was carried out using the scanline sampling technique on rock exposure surfaces. In the Estação deposit, due to the lack of mining accesses, the analysis was based mainly on boreholes carried out nearby. Finally, the benches in the Feitais deposit were studied using the representativeness method, which is more efficient despite being less detailed. The QSystem, RMR, and GSI geomechanical classifications were applied based on the fieldcollected data. These were crucial to obtaining behavioral and stability analysis parameters using software, Potvin's graphical method, and proposed support. It is concluded that all the benches have unstable shafts due to the dimensions and discontinuities present, requiring cables as a support method, except for the secondary cross bench due to the adjacent paste fill.
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Keywords
Benches Face Mining geomechanics Structural stability Aljustrel mines Bancadas Geomecânica mineira Estabilidade estrutural Minas de Aljustrel