Access having been gained to the Red Tower and the south-east bastion in 1989, the excavation works that began in 2003 were designed to render another area accessible to visitors. Between then and 2007, at great constructional expense, the south-west bastion with its two-storey casemate and the castle moat were exposed.

First, the Schlossplatz was opened up so that the castle moat could be laid bare. Once that work had been completed, it was closed over again with a concrete ceiling.

The connection to the Historisches Museum Saar was made by breaching the west wall at the second basement level. From then on, visitors could go down into the former moat via a metal walkway, have a look at the south-west bastion, contemplate a baroque retaining wall and walk through the two-storey casemate.

These excavations, the most recent until today, were the first to satisfy the demands of thorough excavation documentation.