Wed. @ 4:02 am a rock burst occurred on 4000 level apprx 30 ft w. of 4000-197 blind raise sill in the main drift & in 3700-230 raise. (3700-230 raise is directly above area on 4000 level) Damage in 4000 drift consisted of hanging wall blowing out 10 ft of rib & back shaken up around 20 ft. Damage in 3700-230 raise consisted of back/hanging wall blowing out 6-8 ft & broken timber.