Editing Bilbao (section)

=== Mining and ironworks ===
Iron is the main and most abundant [[raw material]] found in [[Biscay]], and its extraction has been legally regulated since 1526. Mining was the main [[primary sector of the economy|primary activity]] in Bilbao and the minerals, of great quality, were exported to all over Europe.<ref name="siderurgy">{{cite web|url=http://www.periodistasvascos.com/imagenes/cap_6.pdf |title=Bessemer cambió la historia |author1=Diez Alday |author2=José Antonio |work=Bilbao 700 |access-date=16 October 2008 |url-status=dead |archive-url=https://web.archive.org/web/20080724095122/http://www.periodistasvascos.com/imagenes/cap_6.pdf |archive-date=24 July 2008  }}</ref> It was not until the second half of the nineteenth century that an ironworks industry was developed, benefiting from the resources and the city's good communication links. In the 20th century, both Spanish and European capitals imported around 90% of the iron from Biscay.<ref name="siderurgy"/> Although World War I made Bilbao one of the main ironworks powers, a subsequent crisis prompted a decline in the activity.