00592nam 2200157z- 450 9910689829403321(CKB)5470000002333079(EXLCZ)99547000000233307920230503c1976uuuu -u- -engLongwall gob degasification with surface ventilation boreholes above the Lower Kittanning coalbedWashingtonU.S. Dept. of the Interior, Bureau of MinesBOOK9910689829403321Longwall gob degasification with surface ventilation boreholes above the Lower Kittanning coalbed3193488UNINA