A roof fall was found at 10:30 am in the 2nd East Sub-Main, #5 entry, 30+10, during a rock dust survey being taken by MSHA. The fall was 40'X19'x7' and had been mined in March 2009. The area had been supported with 6' and 8' roof bolts and was caused by an undetected slip in the mine roof. Ventilation or passage of men was not affected.