History
The Sociedad Industrial Asturiana (S.I.A.) originated in a company founded in Paris in 1879 by José Tartiere and Policarpo Herrero as the Sociedad de Minas y Fábricas de Moreda y Gijón, which inaugurated its first blast furnace at Moreda in 1880. In 1886 the mining and metallurgical arms of the business were separated, with a distinct Sociedad Anónima Fábrica de Moreda y Gijón created for the smelting side. On 1 April 1895 the Sociedad Industrial Asturiana «Santa Bárbara» was constituted in Oviedo, and on 31 October 1899 it acquired the Sociedad Anónima Fábricas de Moreda y Gijón, consolidating both operations.
The S.I.A. began mountain coal workings in the Grupo Santa Ana area of Aller from 1916, exploiting coal seams by means of a network of inclined planes and adit-served levels from the hillsides above the Aller valley. As these mountain groups were progressively exhausted through the following decades, the company turned to shaft sinking to access deeper reserves. The Pozo San Fernando at Orillés was sunk by the Sociedad Industrial Asturiana «Santa Bárbara» from 1942.
It was designed as a balanza or counterweight shaft, a form dictated by the topography of its mid-hillside location. The shaft reached a depth of 253 metres and served four underground working levels. Its extraction system differed fundamentally from conventional vertical shafts: the headframe and winding machinery at the top of the shaft were used only for counterweight operation, while all miners and coal entered and exited through the Socavón Santa Ana, an adit 1,850 metres long driven at the base of the valley.
Miners entered through this adit, boarded cages inside the shaft, and ascended to the working levels. Coal loaded into the cages descended by counterweight to the adit level, from where it was transported outward through the socavón to the loading area at the bottom of the valley, where the Cargaderos de Santa Ana stockpiled the output. The shaft is recorded as having entered production around 1948 and served the colliery until 1968.
The S.I.A.'s mining operations were absorbed into HUNOSA — Hulleras del Norte S.A. — the state-owned coal company created in 1967, which took over Spain's principal private collieries. Following integration, the Pozo San Fernando and the associated Socavón Santa Ana were closed in 1968. The 15-metre-high steel headframe, the machinery building adjacent to the shaft, and the mouth of the Socavón Santa Ana at the valley floor survive intact.
The site is now within a mountain recreational area administered by the regional tourism authorities and is accessible on foot via a waymarked green trail from the village of Orillés, with an approach on the PR-AS 205 route. The site is considered an example of industrial heritage of considerable technical singularity on account of its counterweight extraction system.