The open pit mine was put into operation in 1978. Every year about 0.3 cubic kilometres are moved, so that coal and soil with a volume of about 18.6 km³ will be mined by the time the coal runs out in 2040. By April 2009, the overburden, which was hitherto incurred in Hambach is now transported by conveyor belt in the now exhausted Bergheim mine to fill this in again. Now it is tilted exclusively on the western edge of the opencast mine and on the Sophienhöhe. Due to the accumulation of about 1 km³ of material at the Sophienhöhe and the extracted coal, a residual hole is created, which is to be filled up with water after completion of the mining activities.