Análise estrutural e geofísica em maciço fraturado da frente de lavra NE da mina Osamu Utsumi, Poços de Caldas - MG

• Autor(a) principal: Arruda, Nathássia Moreira [UNESP]
• Data de Publicação: 2018
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/204051; http://www.athena.biblioteca.unesp.br/exlibris/bd/capelo/2019-05-23/000914910.pdf
• topic: Geologia estrutural; Geofisica; Mineralogia; Indústria mineral; Drenagem ácida de minas; Hidrogeologia; Sulfetos minerais; Polarização induzida; Poços de Caldas (MG)

The mining activity is an agent of intense influence in the environment, since the mineral extraction entails in the physical-chemical instability of the rocks recently exposed to the atmospheric conditions. The formation of Acid Mine Drainage (AMD) is a frequent problem in mining sulphide rocks. The interaction between rainwater, oxygen in the atmosphere and sulfide contained in the rock results in the formation of sulfuric acid, which acidifies the surroundings and contributes to the mobility of heavy metals such as Fe, Mn, Zn, Cu, U, among others. The study was carried out in the geological context of the Maciço Alcalino de Poços de Caldas, and its objective was to identify the hydrogeological flow of the fractured rock mass that constitutes the NE open mining front of the Osamu Utsumi Mine (MOU), which exploited the uranium oxide associated to disseminated sulphides in the mid 90's, and today MOU presents a series of AMDs that prevent its decommissioning. A combined analysis of the geophysical methods of electroresistance and induced polarization associated with a structural analysis was used to delimit the saturated zones concomitants to the sulfide areas that originates the current AMD. A structural analysis of the massif indicated that its flow is associated with the presence of fracture connectivity. With the geophysical data collected in the field, profiles and block diagrams were elaborated and allowed the visualization and interpretation of the relations between the anomalous zones, so that the zones of low resistivity that presented values inferior to 126 Ω.m and the zones of high chargeability with values greater than 6.5 mV/V defined the sites of generation of AMD