The Imperial headquarters on Mimban was the centre of government for the five mine towns, plus the location of the prison. It was converted from ruins originally built by one of the native species of Mimban, though the Imperials did not believe the Mimbanites or Coway were responsible, but rather an extinct species.
The structure was a gray stone ziggurat, and was made of gray stone inside and out. To dress up the spartan surroundings the offices of the Captain-Supervisor were lavishly decorated with fur, both real and artificial. The offices also contained a false wall hiding a Viewscreen. In the rear of the facility were holding cells for minor offenders, while another part of the structure near an outside wall had been converted into a secure jail.
In 2 ABY the headquarters housed the administration of Captain-Supervisor Grammel. Princess Leia Organa and Luke Skywalker were briefly held prisoner in the facility's jail.