The future "Trierer Kalk- und Dolomitwerke J. Itschert & Co." is founded by Johann Itschert; permission is obtained to erect two lime kilns.
The company is taken over by Rheinisch-Westfälische Kalkwerke AG.
Josef Schnuch is appointed deputy member of the managing board at the age of 23.
Josef Schnuch buys TKDZ.
The present-day Josef adit is driven. From this point on, extraction is exclusively carried out underground.
Dolomitwerke Wülfrath GmbH buys TKDZ from Josef Schnuch, who continues to shape the company as CEO until 1976 and subsequently as a member of the company council.
The Trier-based entrepreneur Winfried Meseke buys TKDZ.
TKDZ becomes part of the PORR Group.
In the interests of balanced and sustainable dolomite extraction, the company begins backfilling the Josef adit with foreign materials for the first time, in addition to their mining operations.
The company obtains permission for a general operating plan until 2069.
The company establishes its own mine rescue team.