 Excavations at the quarry were stopped in 1881 , although it was not exhausted of fossils , as recent drilling operations have shown . During World War I , when the town was occupied by German forces , preparations were made to reopen the mine for <unk> , and Otto <unk> was sent from Berlin to supervise . The Allies recaptured Bernissart just as the first <unk> layer was about to be uncovered . Further attempts to reopen the mine were hindered by financial problems and were stopped altogether in 1921 when the mine flooded . 
