Baron Renaud Oscar d'Adelswärd (1811–98) was president, and contributed the Usine du Prieuré of Mont-Saint-Martin and the concession of the iron mines of Herserange.

[1] Labbé and Adelsward had previously co-founded the Comptoir de Longwy in 1876, with Alexandre Dreux as the first executive director.

[1] In the early years the Aciéries de Longwy suffered from technical difficulties and a reduced demand for rails.

[2] The company hired Charles Walrand from Le Creusot as technical director, an expert in steel technology, but were still unable to produce steel rails with the quality demanded by the Chemins de fer de Paris à Lyon et à la Méditerranée.

Dreux at once cut back costs and obtained a large contract to supply rails, making the company profitable within a year.

[4] In 1889 the company had 1,592 employees and workmen, six iron mines, seven blast furnaces, three 15 ton basic converters, as well as rolling mills, shops, foundries and other facilities.

Dreux undertook a series of upgrades to the plant, adding new blast furnaces to supply molten pig iron to six basic Bessemer converters at Mont-Saint-Martin.

Despite a huge funeral for the dead worker, and inflammatory speeches by Alphonse Merrheim, the strike soon ended with few concessions by the owners.

[10] About a third of the equipment that the Germans had taken during the war was recovered and reinstalled, and in 1920 two blast furnaces, a Thomas converter and a rolling mill started operation.

[11] Immediately after the war Aciéries de Longwy and its partners founded the Sociéte Lorraine Minière et Métallurgique to take over the Röchling steelworks at Thionville and 40% of the Röchlingische Eisen und Stahlwerke in the Saar.

Two non-Lorraine companies that would further process the Sollac products were included, Forges et Aciéries de Dilling (in the Saar) and J.-J.