The first 50 years of Tinfos NIZI from 1898 to 1948 have left in the history names of some of the vital "builders" of the company:
- The founder Nicolas Zimmer, President of Companie des Mines et Métaux, SA, founded in 1923, and his wife Anna Maroldt who was elected Vice-President of the Company after the war in 1945. She died in 1947.
- Georges Brasseur, Mr. Zimmer's main associate from 1923 and Managing Director of the Company and Board member from 1923 to 1967, and his wife Annette Mayrisch niece of the well known Emile Mayrish who was the President of the Luxembourger steel company ARBED from 1920 until his accidental death in 1928. Mr. Mayrish initiated the first dialogues between the European steel producers.
- Albert Marcour, the specialist of Thomas slags, shareholder and member of Board of Directors for 50 years from 1929 to 1979.
- Jean-Pierre Colling, working with Nicolas Zimmer from 1916 on, and taking part in the whole development of NIZI between the two world wars.
- Managing Director of the company after the death of Nicolas Zimmer in 1941, while Georges Brasseur and the founder's son, Fernand Zimmer were in the United States. Mr. Colling died prematurely in 1950 when he was only 50 years old.
- Max Kuborn, one of the Directors of NIZI. He died in 1943, 58 years old.
- Max Lambert, President of the Board of Directors during the war in the absence of the main shareholders. He held this position until 1957.
- Several others like Julie Melma, Albertine Fousse, Lucie Ensch, Anna Braun, Emilie Weiler, Anna Kremer Stemper, Julie Majerus, Georgette Beffort, Lorry Wagner, Irma Beckius, Eric Korn, A. Dornseiffer, Nicolas Hoffmann "Männchen", Raymond Godbillon, Batty Klein, Emile Bous, Léon Doering, Oscar Steiner and Marcel Vandekerkhove.