A roof fall occurred in # 3 entry, 8xc of J Mains and meas. 25' in L. 40' W X 7' H. The fall was found on a preshift exam. Two pre-shifters were U.G. when cave was found. Entrances to cave were timbered and dangered off. Ventilation was not interrupted. Men were instructed on alt. escape way. Roof was bolted with 4' fully grouted resin bolts and 12' cable bolts.