Quarry of Quenast

Quenast quarry is Europe’s largest open-pit quarry with an area of 140 hectares and is up to 125 metres deep in places. Porphyry, formed 435 million years ago from cooled magma, has been mined here since the 17th century. This is a very hard rock and was traditionally used to make the famous Belgian cobblestones. Today porphyry is used for ballast and gravel.