While MSHA inspector was enroute to examine the AC seals encountered a roof fall in the 7th SW submains between xc 22 & 23, which he believed impaired the ventilation to the AC seals, per citation #9045464 issued on 6-4-15 at 15:10. The operator made curtain adjustments, supported around fall. Approx 40' x 18' x8'. Spad # 18+00 to 18+90.