Rescuers from the Mountain Police (PGHM) in Chamonix scrambled helicopters twice yesterday to try to find Christophe Van Boxtel, a Belgian snowboarder last seen on Monday at 1:40 p.m. at the bottom of the Aiguille du Midi cable-car. Unfortunately, their efforts have so far failed to find any trace of this 35 year old man who at the time of his disappearance was wearing black ski gear. At the same time, the PGHM responded yesterday to a knee injury in the Pré du Rocher, coming down from the Plan de l'Aiguille.