Much of the additional work on the port infrastructures was completed soon after the Spanish Civil War. In 1941, the work was started on building Espigón II that, standing at an angle to the second and third alignment of the Ferry Terminal, enlarged the ports berthing line by 645 metres and was completed in 1944. The new breakwater was to become the destination for general cargo traffic. In 1941 work began to improve the Parque de Carbones, building two taller outer walls to increase storage capacity by 6,000 tones and other work such as the increased railway network, the new water distribution layout, electric wiring, paving and the construction of many buildings for services and repair shops.
Consolidating the industrial function of the port
As a result of the policy of national self-sufficiency followed by Spain after its Civil War, El Musel was to experience the best years of its existence in terms of shipped coal traffic between 1940 and 1960. In 1944, movements of almost 2,250,000 tons were recorded, with the record of almost 2,800,000 tons being reached in 1956. As a significant piece of data, during the first half of the 40s, total port traffic was higher than that of all other Spanish ports combined. However, with the economic liberalisation established in the Stabilisation Plan decreed in 1959, loaded coal traffic slid along a downwards slope and, in only a few years, the site went from being an eminently coal exporting port to an importer of that same product (thermal coal). Moreover, during that same period the fishing sector boomed due to the excellent fishing enjoyed by paired trawlers that auctioned off up to 7,159,951 kilos of fish in 1946. Shortly afterwards, a new wharf was built between the third and fourth alignment of the Ferry Terminal that was large enough to house a large deep-sea fishing fleet based in Gijón. Meanwhile, at the expense of the local Unión de Armadores de Buques Pesqueros, modern fishing facilities equipped with an ice factory and a large fish market were completed next to the wharf.