La Felguera, Langreo
The rich coal deposits in the Candín river valley, in Vega (Langreo), started being exploited in the second decade of the 19th century. These were initially in the hands of Alejandro Aguado, Marquess of Las Marismas, who promoted Sociedad Minas de Carbón de Siero y Langreo in 1925. Later, it was Fernando Muñoz y Sánchez, Duke of Riánsares and husband of the queen regent María Cristina, who took over these mines. Determined to extend his mining interests to the Caudal and Nalón river valleys, Muñoz had acquired in 1844 Asturian Mining Company or Compañía Anglo Asturiana, which had unsuccessfully tried to set up a steelworks in Mieres. Finally, after another unsuccessful attempt by the company set up by Muñoz and his partners, Compagnie Minière et Métallúrgique des Asturies, it was the French businessman Numa Guilhou who managed to consolidate the project. It was named Fábrica de Mieres in 1879, being under the management of the engineer Jerónimo Ibrán.
In 1918, Fábrica de Mieres began the works to sink the San Enrique or Candín mine shaft. This was interrupted shortly afterwards, probably due to the economic difficulties the company was experiencing. In 1925, the exploitation passed into the hands of Sociedad Minas de Langreo y Siero, which took over part of the Guilhou company's concessions.
In 1929, the work was resumed to be completed in the following decade. The headframe was erected in 1933, although it was refurbished in the 1960s, together with the extraction machine and the compressors. The remaining elements of the first construction phase are the workshop and forge building, the buildings that housed the compressor room, the boilers and the power plant, as well as the ventilation building. In 1942, the office building designed by the Somolinos Brothers was built. In 1957, the same happened with the toilet block and, in the following decade, the headframe, the engine house and the loading dock.
After its incorporation into HUNOSA, the San Enrique or Candín II mine shaft was re-sunk and connected to the Santa Eulalia or El Cabritu mine shaft (Candín I), as well as with the Fondón shaft, via a 1.5 km gallery under the Nalón river. In December 2012, it ceased its activity.