A roof fall occured in the 14 North Panel, #10 entry, starting in the pillar line between #10 and #11 crosscut and ending in the middle of the intersection of crosscut #12. The fall measured approximately 100'X18'X6'-8'. The area was supported with 6' tension rebar bolts and 9' mega bolts. An undetected slip was determined to be the cause of the fall.