A reservation is not necessary for individual visitors!
The departure times of the tours are at 2:30 pm, 3:30 pm and 4:30 pm. The language of the tour depends on the majority of visitors present; audioguides in German, French, English and Dutch are available. Access to the underground mine is always accompanied by a guide.
If you are a group of at least 16 people, it is possible to reserve. For group reservations of less than 16 people, the price will be 120€ per group.