A roof fall occured in the 1 Main East, crosscut #118, starting at the edge of the pillar line between #5 and #6 entries and ending 4' into the intersection of #7 entry. The fall measured approximately 94'X19'X3'-7'. The area was supported with 6' tension rebar bolts and the intersection was x-ed out with 9' mega bolts. An undetected slip was determined to be the cause of the fall.