The Hambach opencast mine is located between Jülich in the Düren district and Kerpen (Rhein-Erft district) in the heart of the Rhenish lignite mining area. Mining started in 1978 near the Hambach district of Niederzier. At peak times, the opencast mine, which is up to 411 metres deep, produced so much lignite for the company's own power plants that it covered five per cent of Germany's total electricity demand.

In 2029, coal extraction in the Hambach opencast mine will end as part of the statutory coal phase-out. Several major regional planning, mining law and water management approval procedures are currently underway. They will determine how the landscape, characterised by a large lake and forest, will look like which the opencast mine will leave behind. For example, the Hambach lignite mining plan is currently being amended. In a few weeks, a planning approval procedure will begin that will decide on the design of the opencast lake in detail. At the same time, another lignite plan procedure will secure the route for the outlet of the future opencast reservoir.