EMPLOYEE WAS OPERATING A FRONT END LOADER. EMPLOYEE WAS LOADING A PORTABLE SCREENING PLANT WHENA DISCHARGE CHUTE LOCATED UNDER THE SCREEN PLUGGEE RESULTING IN AN OVERLOADED STRUCTURE. THE EM PLOYEE CHUT THE SCREEN AND WAS ATTEMPTING TO CLEAR THECHUTE WHEN THE STRUCTURE FAILED AS RESULT OF AN OVERLOADED. THE EMPLOYEE WAS STRUCK BY THE CHUTE. EMPLOYEE SUFFERED A BROKEN COLLAR BON