Mineralizações manganesíferas supergênicas enriquecidas em tálio na Mina Perdizes, São Desidério, oeste do Estado da Bahia: tipologia, mineralogia e associação metálica do minério.

Abstract

The State of Bahia has important manganesiferous districts, specifically in the western region, generated in sedimentary and supergenics conditions, requiring depth investigation on its metallogenesis, in the face of recent discoveríes of rare metais (thallium, cobalt and scandium) associated with it. Therefore, the focus of this study is the metallogenic research in larger area mined manganese in western Bahia, in the 80s and 90s, that was the Perdizes Mine. To achieve the objectives of this research, field visit was carried out sampling, Diffraction Studies X-ray (XRD) and Chemical analyzes to determine the content of manganese, iron and thallium. The geological subdivision of the region is expressed by lithologies of marine sedimentary origin, of neoproterozoic age (Bambuí Group), which are covered by wind continental sedimentation cretaceous age (Urucuia Group), and finally, superimposed on this whole package, occur unconsolidated cenozoic covers, detrital-lateritic. The geological setting of Perdizes Mine, consists of lithofacies governed by processes and pedogenetic action, active in this portion of Sanfranciscana Basin. Being them, from bottom to top: saprolite facies, oxidized horizon facies, ferruginous horizon facies, and oxisol facies. Diffraction X-ray (XRD) studies, show that manganese concretions, dense blue-gray color and concretions of laterite, were the only types that feature manganese minerais in the mine geologic framework. Chemical analysis indicated that the supergene process, trainer of manganesiferous mineralizations, They were more intense in the highlands of Urucuia, than in relation to intervalleys areas in western Bahia.