The Garzweiler opencast mine is located to the west of Grevenbroich and is moving in the direction of Erkelenz.

The open pit operator RWE, then known as Rheinbraun, initiated the permitting process for open pit mining in 1974 and was able to commence operations in 1978. The first excavator began its work on 15 October 1978. This was accompanied by the resettlement of local villages and towns and the largest forest area in the region, the Hambacher Forst, was largely cleared.

The pit is currently about 6 km wide and 320 metres deep. 1600 people work today in the mine, although a few years ago, the figure was 6,000 people. The decline has come about because of the reduction in the world price of coal. At present rates of extraction, the mine will be workable until 2040. Before then, three villages will have to be relocated, plus a major railway line and a trunk road.

Special machines have been built to extract the coal and the surrounding sediments. Transportation within the mine is by conveyor belts. The machines can be 220 metres long and 50 metres high. The cutting wheel is about 20 metres diameter.