The two southern branches were intended as a delay line. The northern branch followed the Geleen Brook, and the southern branch the river Geul. Both tactical lines consisted of a belt of casemates designed to slow down the advancing German troops as much as possible so that there would be time to put the bridges over the river Meuse and the Juliana Canal out of order.

Lieutenant Colonel Albert Govers, the Territorial Commander of South Limburg, was responsible for the construction. Casemate 6 was located near Mechelen and was part of the thirty casemates of the Geul Line. A special feature of this casemate was the good view of the river Geul and the foothills of the Vijlenerbos and the Elzetterbosch woods.