[1] Although more than 20 Asturian municipalities are officially considered mining councils, in different categories, the municipalities that make up the two regions most directly linked to coal and which have had the greatest historical importance in economic, social and cultural matters are popularly referred to as mining councils, such as Caudal Valley (Mieres, Lena, Aller, Ribera de Arriba, Morcín and Riosa) and Nalón Valley (Langreo, San Martín del Rey Aurelio and Laviana).
On the other hand, some municipalities in the Nalón valley region, such as Caso and Sobrescobio, maintained an economic activity not very closely related to industry and without large urban centers.
It was at this time that the vertical shafts began to deepen to the detriment of mountain mining, giving rise to the recognizable silhouette of the headframe in the landscape.
The situation was sustained thanks to the protectionist policies of Primo de Rivera, the Second Republic, the upturn due to the Second World War and Franco's autarchy,[6] which made it the area of greatest mineral production in Spain.
For more than a century, thousands of families from the rest of Spain settled in the Mining Basins, with special relevance to the waves of immigrants arriving in the 1940s and 1950s from Andalusia, Extremadura and Galicia.
These funds, however, were managed with little responsibility, subject to continuous delays or systematic stoppages, especially on the part of the regional government, when they were not used for many projects independent of the economic regeneration of the Mining Basins.
[15] During the government of José Luis Rodríguez Zapatero these funds were frozen in practice[16][17] and finally the closure of the mining industry was signed in 2010.
In 2011, the European Union ruled the closure of all unprofitable mines by 2018, establishing a timetable from 2013 for the seven remaining wells in Caudal and Nalón, and later projected the end of the aid in 2014.
[18] In 2012, faced with the beginning of Mariano Rajoy's government's policy of cuts in mining, there was a great escalation of conflict[19] with a total strike at Hunosa (as in other mining areas of Spain), the regular blocking of road and rail communication routes in the Principality and very violent clashes between authorities and miners in the mountains and in the town center, causing numerous injuries and arrests, as had already occurred in the early 90s.
In spite of the demolitions carried out in recent years, the basins conserve large groups of industrial heritage (numerous mine shafts and small mountain and open-well mines, La Felguera factory, Nitrastur factory, stations, bridges, workers' quarters, engineers' cottages, workshops, etc.)