A former coal mine site in the Cuenca Minera de Sabero, a coalfield worked continuously from the nineteenth century until 1991.
Mina de Valdoré is located at Olleros de Sabero in the municipality of Sabero, León, at the heart of the Cuenca Minera de Sabero. Olleros de Sabero was a major centre of coal mining within this cuenca: by 1840 the area had been assessed as "carbonífero rico" by a mines engineer, and five mining concessions were immediately registered. The district was worked by various operators from the mid-nineteenth century, with principal exploitation carried out under Hulleras de Sabero y Anexas S.A., founded in 1892.
The Hulleras de Sabero group operated at Olleros through several concessions and installations including the Pozo Herrera I, which entered service in 1912 as the first vertical shaft sunk in the province of León. The company ceased operations at Olleros in 1968 when production was concentrated at Pozo Herrera II in Sotillos, and Hulleras de Sabero finally closed in 1991–1992. No specific operational history, production data, structural information, or closure record for the concession name Mina de Valdoré has been identified in the sources consulted.
Mina de Valdoré is recorded as a coal mine site at Olleros de Sabero in the Cuenca Minera de Sabero. The cuenca was among the earliest coalfields to be exploited industrially in Spain. Mining at Olleros de Sabero is documented from at least 1840, when the terrain was officially described as "carbonífero rico" and five concessions were immediately registered. Roman-era silver mining is attested in the wider Sabero district, with the place name Valdoré also appearing in sources describing Roman-period extraction in the region.
The dominant operator in the district across the late nineteenth and twentieth centuries was Hulleras de Sabero y Anexas S.A., constituted on 7 September 1892 by Basque industrialists who acquired the former Minas de Sabero concessions and added those belonging to Tomás Allende. The company built and operated a 600-millimetre-gauge narrow railway connecting its installations at Olleros and Sotillos with the main-line station at Vegamediana and Vega Barrio, and thence to Cistierna, supplying coal to the Ferrocarril de La Robla and to Basque steelworks. At Olleros, the main extraction points were the Pozo Herrera I (from 1912, the first vertical shaft sunk in León province), a Socavón Sur within the Sabero 4 concession (registration number 648, dated 9 December 1866), and associated mountain workings including the Mina Sucesiva and the Mina del Tercero de Olleros.
The concession registration date of Sabero 4 (9 December 1866) establishes that mining rights in this specific area of Olleros were formally recorded from that date. Production at the Olleros group was concentrated at Pozo Herrera II in Sotillos from 1968 onwards. Hulleras de Sabero y Anexas formally ceased mining operations in 1991–1992, with the last installations closing on 31 December 1993. What remains of the Olleros surface infrastructure — aside from the Pozo Herrera I structures — is largely in a state of abandonment.
No sources consulted contain specific operational history, production data, company succession records, structural description, or closure information specific to the concession name Mina de Valdoré as a distinct identified working within this landscape.