The mine Cockerill d’Esch-sur-Alzette played a major role in Luxembourg’s economic boom. This mine is known as a unique mine endued with a colliery, and the extraction was largely made by galleries.

From 1881 to 1943, owners of the area known as the Collart brothers, exploited 28 hectares of the concessions of the mines in Katzenberg, where the mining took place. In 1945, after the German occupation, John Cockerill directed the mine until its closing in 1967. As a consequence, the installations were dismantled and the state got proprietorship of the site until 1986.

The association Entente Mine Cockerill, composed of a group of motivated mine workers, renovated the site and buildings involved. Currently, one of the houses is used as a museum where mine utensils and traditional heat lamps are displayed. In addition, photographic archives showcase the arduousness of mine work.

The site is open throughout the year, each morning beginning at 9:30am. Groups are asked to make an appointment in advance through the Centre Ellergronn, which is located at the same site. Here you also will find a restaurant and information about indigene biota. In addition, guided tours are offered at the natural reservation in Ellengronn.