La Foz, Morcín
La Esperanza Adit
The coal deposits in the area were exploited by the Trubia Weapons Factory from 1846 onwards. Due to the high production costs and the difficulties in transporting the coal, the factory in Trubia stopped its operations a few years later. These concessions were auctioned off and acquired in 1899 by Sociedad Anónima Minas de Riosa, which was set up that same year thanks to Asturian capital and the participation of the Figaredo and Sela families.
In 1905, Minas de Riosa transferred all its properties to two French companies, Houllières de Ujo et Mieres and Societé Française des Charbonages de Laviana. In 1914, the mines were auctioned off again and the company was taken over by a group of investors from Asturias, including once again the Figaredo family. The name of the company was then changed to Hulleras de Riosa, S.A.
In 1952, the state-owned company ENSIDESA acquired Hulleras de Riosa to ensure the supply of coal to its plant in Avilés. ENSIDESA, which would carry on with the mining exploitation until the integration of its mining assets into HUNOSA, conducted major modernisation works on the facilities, including the sinking of the Montsacro Mine. The works were attributed in 1953 to the construction company Entrecanales y Távora. In 1959, the 40.20-metre-high welded steel headframe was installed, and the stable coal extraction began.
The mine also had a mine school where workers received training before joining the mine works. For this purpose, an adit was built with two entrances and a main gallery with different divisions used for internship works inside the mine.
Once in HUNOSA, the mine was incorporated into the San Nicolás mining group, together with Nicolasa and Olloniego. The railway line connecting La Foz and La Pereda, which had served the mines in the area, was eventually dismantled and the coal started to be transported through the road. Later, a conveyor belt connected with the San Nicolás Mine came into operation, transporting the goods to El Batán coal washing plant.
In December 2014, the Montsacro Mine was closed, having reached a depth of 350 metres distributed in 7 floors.