A roof fall occurred in the #9 seam in the 2 Main East, #9 entry, 1/2 the intersection of xc 19 and extending through the pillar line towards xc 20 and from 1/2 the intersection of xc 19 through the pillar line towards #10 entry. The fall measured approximately 60' x 18'x 6'-9'. An undetected slip was determined to be the cause of the fall.