A ROOF FALL OCCURRED MEASURING 30' L X18' X 6 1/2' IN THE #1 ENTRY, SPAD 11+40 IN THE 2ND SW SUBMAIN. THIS WAS OUTBY THE TAILPIECE OF #1 UNIT IN AN ENTRY THAT HAD BEEN DROPPED OFF. THE FALL WA S DANGERED OFF AND TIMBERED OUT. THE MSHA OFC @ BEAVER DAM WAS NOTIFIED.