A roof fall occurred in the #9 seam, in the 18 north, #10 entry, just inby the intersection of crossuct #21 and ending just outby the intersection of crosscut #39. The fall measured approximately 970' x 18' x 5' The area was supported by 5' fully grouted roof bolts and 9' mega bolts. An undetected slip was found to be the cause of the fall.