A ROOF FALL was discovered on the 001-0 section during preshift examination. The fall measured app. 4' thick X 20' wide X 65' long. The fall occurred in the crosscut from the No. 5 to the No. 4 heading & through the No. 4 intersection. The crosscut had been cut through at the end of the 2nd shift on 9/26/09 & had not been bolted prior to the end of the shift & had been left down.