A ROOF FALL ON RT 4 SECTION UNINTENTIONAL CAUGHT THE MINER. THE MINER HAD FINISHED 1ST LIFT OFF RT HAND BLOCK 5 ENTRY AND WAS BACKING OUT, WHEN THE FALL OCCURRED. THE ROCK WAS ONE BIG SLAB WAS 0-6' THICK. VENTILATION OR PASSAGEWAY WAS NO CHANGED. NO INJURIES.