The Compañía Cantábrica de Santa Ana, founded by Partington himself and financially linked to Herrero y Compañía was the first company to exploit the coal deposits in the area. After its liquidation in 1867, its assets were sold to the Sociedad Hullera de Santa Ana, a french company linked to the Herreros. Years later, this company became part of the Sociedad Carbones de Santa Ana and finally, in 1877, the Sociedad Herrero Hermanos.
Santa Ana mines already had the Langreo-Gijón railway to sell their coals, but, above all, Santa Ana mines had coal demand from Duro y Compañía, which in 1859 had lit its first furnace in the neighbouring council of Langreo.
After the business restructuring of Duro in 1900 (Sociedad Metalúrgica Duro Felguera, SA or SMDF from then on) a change in strategy towards vertical integration was initiated, acquiring the Santa Ana mines in order to control the raw materials needed for the furnaces.
The need for more coal led Duro to take over other mining companies and modernise its operations and transport.