Influência da fase gasosa como ferramenta auxiliar no diagnóstico do potencial de geração de drenagem ácida de rocha

• Ano de defesa: 2013
• Autor(a) principal: Carolina Bittencourt de Abreu
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Gases; Diagnóstico; Hidrogeoquímica; Pilha de estéril; Drenagem ácida de rocha; Engenharia metalúrgica; Tecnologia mineral
• Link de acesso: http://hdl.handle.net/1843/BUBD-9CAF6P

Waste rock piles are a three-phase system where the air flow acts in a crucial form on the dynamics of the geochemical processes. The geochemistry reaction of sulphide oxidation is favored as greater is the contact of this material with oxygen, whereas large volumes of water are not required for their occurrence. The research presented in this thesis proposed the geochemical characterization of acid drainage produced by a waste rock pile, based on the distribution and concentration of gases within it, from the atmosphere and other gases produced in the sulphide oxidation process. For its development a uranium waste rock pile has been used as object of this study, which currently generates wastewater with a pH about 3.5. The mining and metallurgical enterprise, under the management of the Nuclear Industries of Brazil (INB), is located in the municipality of Caldas, Minas Gerais. This was the first site of mining and processing of uranium ores in Brazil and the activities occurred between 1982 and 1995. Gas samples from the uranium waste rock pile were collected at 40cm depth and stored in vacuum tubes. Concentrations of O2, N2, CO2, H2 and Ar were measured ex-situ via mass spectrometry. Temperature measure were also taken at 40cm depth. In addition to gas samples, samples of the material constituting the pile, and surface and groundwater samples were obtained and properly characterized. Through the study of the behavior of gases at 40cm depth was possible to identify the regions most susceptible to generate acid mine drainage. The study of the gases flow through the pile was supported by the studies of the solid and aqueous phases of the system. The methodology was efficient and economically viable for the characterization of sites generating acid mine drainage. By adopting this approach, it is hoped assist entrepreneurs in making decisions on decommissioning process of waste rock piles and rehabilitation of areas degraded by mining activities.