Fully functioning heritage mine museum at La Nueva, Langreo, centrepiece of the Ecomuseo Minero Valle de Samuño, with intact 1930 Art Deco winding house and BIC-listed riveted-iron headframe.
The Pozo San Luis is a disused coal mine at La Nueva, in the valley of the río Samuño, concejo of Langreo, Asturias. Sunk between 1928 and 1930 by Carbones de La Nueva, a subsidiary of the Real Compañía Asturiana de Minas, the shaft reached 420 metres depth across six levels. The 28-metre riveted-iron headframe and its paired modernist-style machinery house — built 1928–1930 and extended in 1945 without compromising its appearance — together with the associated pithead complex, represent the primary operational period of the colliery.
Coal extraction ceased in 1969 when HUNOSA ceased exploiting the shaft, after which it served as auxiliary to the nearby Pozo Samuño until final closure in 2002. In 2007 HUNOSA transferred the installations to the Ayuntamiento de Langreo. The Pozo San Luis was declared Bien de Interés Cultural with the category of Conjunto Histórico by Principado de Asturias Decreto 14/2013 of 6 March 2013.
The Ecomuseo Minero Valle de Samuño opened in 2013, with the Pozo San Luis as its centrepiece, and has received over 14,000 visitors in peak summer seasons.
Mountain coal mining in the valley of the río Samuño, concejo of Langreo, is documented from the mid-nineteenth century. The company Carbones de La Nueva operated mountain workings in the valley, of which the Socavón Emilia (dated 1904 at its portal) and the Socavón Isabel (1896) are surviving examples. In 1925 the Real Compañía Asturiana de Minas (RCAM) acquired Carbones de La Nueva.
The RCAM's interest in securing inland coal was directly linked to the closure of its submarine Arnao colliery in Castrillón in 1915, which had previously supplied its zinc smelting operations. The acquisition of Carbones de La Nueva provided a replacement coal source; coal from San Luis was sent by rail to La Felguera and onward to the RCAM's coastal plants. From 1925 the RCAM initiated the sinking of a vertical shaft at the Pozo San Luis site on the bank of the Samuño, transitioning from mountain mining to deep shaft extraction.
The principal construction phase was 1928–1930, during which the shaft was profundised, the riveted-iron headframe was erected to a height of approximately 25 metres (cited variously as 25 or 28 metres in sources), and the machinery house was built and electrified. The machinery house was designed with particular architectural ambition: it is a two-storey building of 782 square metres floor area, with an associated substation, displaying eclectic ornamental features including staggered pediments, zinc pinnacles with barroco inspiration, three ceramic plaques with mining imagery, and large windows with rationalist profiles. The Siemens winding machine of 1929, installed within the house, survives intact and is demonstrated in operation — without load — to museum visitors.
The machinery house was extended in 1945, a project attributed to the RCAM's architect Tomás Acha Zulaica, though the 1945 addition maintained the composition of the original building. The offices building followed in 1955. In 1968 Carbones de La Nueva was integrated into HUNOSA.
Active coal extraction continued until 1969, when HUNOSA ceased exploiting the Pozo San Luis as a productive shaft. From 1969 the shaft served as auxiliary to the nearby Pozo Samuño (Carbones Asturianos), which had also been integrated into HUNOSA in 1967. The Pozo San Luis's definitive closure took place in 2002.
The sixth and lowest level of the shaft was never exploited, having been permanently inundated. Total shaft depth at six levels was 420 metres. An expediente for BIC declaration was opened by the Consejería de Cultura y Turismo on 9 November 2009.
On 6 March 2013, the Principado de Asturias issued Decreto 14/2013, declaring the Pozo San Luis a Bien de Interés Cultural with the category of Conjunto Histórico. In 2007 HUNOSA had already transferred the installations — the Pozo San Luis, the former railway trench of Carbones de La Nueva, and the El Cadavíu site — to the Ayuntamiento de Langreo, enabling the museum project to proceed. The Ecomuseo Minero Valle de Samuño opened on 6 July 2013.
It is operated by the Ayuntamiento de Langreo and uses the former railway trench to carry visitors on a train from the Estación de El Cadavíu through approximately two kilometres of valley, entering the underground via the Socavón Emilia — the former first level of the Pozo San Luis, now at 32 metres depth — before emerging at the base of the San Luis headframe. The ecomuseo received over 13,000 visitors in its first summer and recorded a historical record of 14,144 summer visitors in 2024.