An unintentional roof fall was discovered behind the #11 scal that was being constructed. The fall occurred over the weekend while no one was present. Discovered on 6/19/06 by foreman at spad #5050. The fall was estimated to be 10' thick X 20'wide X 40' long. Slick and slide rock were present in the fall. MSHA inspector investigated the fall while examining the sealed area.