In 1945 the concession was a quadrilateral 6 kilometers across with parts of 15 communes: Bully, Grenay, Loos, Vermelle, Mazingarbe, Noyelles, Sains en Gohelle, Auchy-les-Mines, Haisnes, Annequin, Cuinchy, Beuvry, Sailly, Lievin and Aix-Noulette.