EMPLOYEE WAS WALKING FROM HOPPER TO FINES PLANT. HE THOUGHT LOADER WAS BACKING AWAY, INSTEAD LOADER CAME AROUND END OF HOPPER STRIKING EE ON HARD HAT W/LOADER BUCKET, KNOCKING HIM TO THE GROUND. LOADER OPERATOR NEVER SAW EE & KEPT GOING, EE ROLLED BETWEEN FRONT LOADER TIRES, FRONT LINE EDGE RAN OVER EE'S LT. ARM FRACTURING BONE.