An unintentional roof fall occurred. 30' long x 20' wide x 9' to 10' high. Was bolted with 6' tension & 8' point anchor bolts at spad #3838, #6 entry 005 mmu, 1-A northwest mains, 2200' outby section. Primary escapeway was blocked, production was stopped. Everyone was brought outby till escapeway was rerouted.