EE WAS WORKING TO DISLODGE LUMPS IN WEIGH FEEDER ROTARY VALVE DOGLEG FROM WHICH GYPSUM IS DISCHARGED. UPON OPENING AN 8"" INSPECTION PORT, HE OBSERVED SEVERAL LUMPS CHOCKING ROTARY VALVE INLET. EE USED A BAR TO DISLODGE LUMPS WHEN THE SILO FLUSHED CAUSING MATERIAL TO ENGULF EMPLOYEE.