Former open-cast uranium mine near Saelices el Chico, Salamanca, the most important uranium deposit in the Iberian Massif, now in ongoing environmental restoration.
Mina Fe, located at Saelices el Chico in the province of Salamanca, was an open-cast uranium mine and the most important uranium deposit in the Iberian Massif. The deposit was discovered in 1957 through airborne radiometric surveying of Precambrian slates in the Ciudad Rodrigo area; a radioactive anomaly designated with the letter F gave the mine its name. Production began in 1974 using heap leaching at a processing plant called Elefante.
A more advanced dynamic leaching plant, Planta Quercus, was constructed between 1991 and 1993 and brought into operation in 1993, producing uranium concentrates up to a maximum of 175 tonnes per year. Mining operations ceased in December 2000, and the Planta Quercus ceased concentrate production in November 2002. Environmental restoration of the mine workings and decommissioning of the Planta Elefante were completed by 2004.
The Planta Quercus, declared to have permanently ceased operations by ministerial order in 2003, has been subject to decommissioning proceedings since 2005. The site is the property of ENUSA Industrias Avanzadas, S.A., a state enterprise. Access is restricted.
The discovery of the uranium deposit at Saelices el Chico resulted from airborne radiometric surveys conducted in 1957 over the Precambrian metamorphic slates of the Ciudad Rodrigo area, approximately ten kilometres north-west of that city. Among the radioactive anomalies identified, the one designated with the letter F gave rise to the name by which the mine and its deposit became known: Mina Fe. Geologically the deposit is the most important uranium deposit in the Iberian Massif, and has been described as the largest known primary uranium deposit of its type in the world. The uranium mineralisation occurs filling fractures and cementing fault breccias that affect the metasedimentary materials of the Complejo Esquisto-Grauváquico, a metamorphic sequence of fine-grained psammitic and carbonaceous pelitic rocks of the greenschist facies. The mineralisation resulted from a hydrothermal process, with two phases of brecciation, the second of which was more productive in terms of uranium mineralisation. Primary uranium minerals at the site include uraninite and coffinite, while secondary minerals include schoepite, torbernite, autunite, zippeíta, uranopilite, and phosphuranylite.
Production at the mine began in 1974, using heap leaching at a processing installation called Planta Elefante. This hydrometallurgical technique involved applying a leaching solution to piled ore to extract uranium in dissolved form. Operations at this first scale of production continued until the Planta Elefante was superseded by a more advanced facility. Between 1991 and 1993 ENUSA Industrias Avanzadas, S.A., the Spanish state enterprise responsible for uranium production, constructed a new dynamic leaching plant at the same site. The environmental impact declaration for this construction was issued on 8 May 1990, and the ministerial construction authorisation on 18 June 1990. The plant, designated Planta Quercus, received provisional authorisation for start-up on 27 April 1993. Operating within a maximum authorised annual output of 175 tonnes of uranium concentrate, the Planta Quercus produced uranium concentrates from minerals extracted from the open-cast mine on the same site. These concentrates were used for the fabrication of nuclear fuel elements. The site is located on the Finca Capilla del Río in the term of Saelices el Chico, with the processing area occupying approximately six hectares at elevations between 670 and 681 metres above sea level.
Mining activities at the site ceased in December 2000. Production of uranium concentrates at the Planta Quercus ceased in November 2002. The final cessation of operations was declared by ministerial order on 14 July 2003. Following closure, ENUSA undertook the decommissioning of the Planta Elefante and the environmental restoration of the mine workings. These tasks were authorised by a resolution of the Dirección General de Política Energética y Minas on 16 January 2001, and were completed by 2004. From early 2006, the decommissioned Elefante site and the restored mine workings entered a period of surveillance and compliance monitoring as prescribed in the decommissioning plan.
A separate decommissioning plan for the Planta Quercus was submitted to the regulatory authorities in 2005. This process was initially suspended, first to allow the Elefante decommissioning and mine restoration to be completed on the shared site before Quercus works could proceed, and subsequently in 2009 to complete a feasibility study on state uranium reserves in Salamanca. In September 2015, following completion of the Elefante and mine restoration works, a new decommissioning plan for the Planta Quercus was submitted. A declaration of environmental impact favourable to the first phase of decommissioning was issued on 9 March 2018. In June 2025 ENUSA sought the initiation of an ordinary environmental impact assessment procedure for Phase I of decommissioning, with the planned decommissioning to proceed in three consecutive phases. The stated final objective is to restore the site to radiological and environmental conditions as close as possible to those existing before mining began. Access to the site is restricted and the property remains under ENUSA ownership.