EE WAS OPERATING THE NOZZLE ON A SHOTCRETE HOSE. A PLUG OCCURRED IN THE HOSE AND THEN BROKE LOOSE. THE HOSE WHIPPED WITH THE PRESSURE CHANGE AND EE FELL TO THE GROUND. HE STRUCK HIS LEFT ELBOW ON VENT LINE THAT WAS ON THE GROUND. HE WAS PLACED ON RESTRICTED DUTY FOR THE INJURY.