With a production capacity of more than 23,000 tonnes of raw coal per day, the Zollverein colliery was once the most efficient colliery in the world. The central shaft XII, built from 1928 to 1932 according to plans by Fritz Schupp and Martin Kremmer, is considered a technical and aesthetic masterpiece of modernity. In 2001, the site was officially inscribed on the UNESCO World Heritage List as the »Industriekomplex Zeche Zollverein«. The coke oven Kokerei Zollverein was built from 1957 to 1961 in cooperation with the coal mine Zollverein.
In addition to the Salzlager, the mixing plant, in which the different coal qualities were blended into an optimal mixture for coking, is also located on this site. Via conveyor belts to bunkers and through hoppers, the coal made its way from the top level of the mixing plant down five levels to the coke ovens.