Traditionally the steelworks of Belgium had been concentrated in the southern half of the country, in Wallonia, close to the historic coal mining areas at the edge of the Rhenish Massif; which in part defined the area that came to be known as the Sillon industriel, including Liège Province and Hainaut Province.

[3] At the beginning of the 1960s preliminary work began towards the construction of a new plant; the canal was to be dredged to enable Panamax size ships to use the canal, Arbed's land holding increased to 211 ha (2.11 km2), and on 27 April 1962 the European Coal and Steel Community approved the plants construction.

[2] The company Siderurgie Maritime NV (Sidmar) was formed on 10 July 1962,[2] with a capital of 4.5billion Belgian franc, of which 2bn came from Arbed, as well as 1bn from Cockerill-Sambre.

[8] By the beginning of the 1980s some re-investment and expansion started again; a continuous rolling mill in 1981, as well as acquiring stakes in ALZ, and Klöckner Stahl.

[2] The company produces ~5million tonnes pa of flat steel, with automotive manufacturers being a major source of custom.