WHILE INSTALLING PIPE AT THE OVERLAND PUMPS THE STINGER OPERATOR WAS POSITIONING THE PIPE. WHEN THE PIPE WAS RAISED, IT SLIPPED & PINNED THE VICTIM BETWEEN THE PIPE ELBOW & THE PUMP MOTOR. HIS LEFT KNEE TOOK THE BRUNT OF THE IMPACT. HE WAS NOT RELEASED TO WORK & WAS EVALUATED BY AN ORTHOPEDIC SURGEON.