Architects William Graatsma and Jan Slothouber were in joint charge of the exhibitions department at Staatsmijnen, one of the largest companies in the Netherlands after World War II. The purpose of this collage was to inform the public about mining. A cubic kilometre of the earth’s crust has been removed, revealing lift shafts, air ducts, galleries and the various layers of rock in cross-section. In the collage is a photograph showing the mining operation above ground.