UNITED STATES DEPARTMENT OF THE INTERIOR BUREAU OF MINES
IMPROVING THE PERFORMANCE OF TUNNEL RAISE AND SHAFT BORING MACHINES FOR COAL MIN - SPRINGFIELD U.S.DEPT.OF INTERIOR 1986 - 29X23
622.26 U58
IMPROVING THE PERFORMANCE OF TUNNEL RAISE AND SHAFT BORING MACHINES FOR COAL MIN - SPRINGFIELD U.S.DEPT.OF INTERIOR 1986 - 29X23
622.26 U58