THE EMPLOYEE WAS ENTERING A HOPPER ACCESS DOOR BELOW THE #1 FINISH MILL DUST COLLECTOR. WHEN HE ENTERED HE WAS ON HIS KNEES IN THE DOOR FRAME. HE LOST HIS BALANCE AND FELL FORWARD AGAINST THE OPPOSITE SIDE WALL. HE CAUGHT HIMSELF WITH HIS RIGHT ARM. EMPLOYEE SUSTAINED A RIGHT ROTATOR CUFF TEAR AND REQUIRED SURGERY. THE FIRST LOST WORK DAY WAS 1/14/04.