Evaluation of REE potential in Portuguese legacy mines

Abstract

REE have unique properties that are mostly used to manufacture high tech devices. Most REE have geochemical properties that cause them to be typically dispersed and not often found in concentrated and economically exploitable forms, and difficult to separate. The ENVIREE project aims to develop environmentally friendly and efficient methods for their extraction from secondary sources. REE contents of tailings from four legacy mining sites have been obtained by INAA and analysed by 57Fe Mössbauer spectroscopy. REE concentrations in the tailings of Covas and Cumieira are more dependent on the REE contents of the primary ores and the treatment to extract the target metals than on the nano-sized oxides present. The tailings’ size, REE contents and Mössbauer results support the selection of the Covas tailing as the one to be submitted for further steps of REE extraction on the framework of the project.

Geochemical Behavior of Lanthanides and Actinides in an Old Uranium Mine, Portugal

“…The uranium production ceased in 2001, and an agreement between the Empresa de Desenvolvimento Mineiro S.A. (EDM) and the Portuguese state was established under an exclusive concession contract and approved by the Decree-Law n. • 198-A/2001, for the environmental remediation of 175 abandoned old mines, then updated to 199 [12,13]. Several studies have been performed in the center-north of Portugal on different types of mine areas (uranium and polymetallic mines), such as the study of the uranium mineral alteration from a Portuguese Variscan peraluminous granite [14], some works concerning the trace element distribution, especially U in the aplite [15,16], and the identification of the most suitable material for REE recovery [17]. In these mining areas, studies regarding the pollution patterns and environmental impact caused by the mine exploitation were performed.…”