UNITED STATES DEPARTMENT OF THE INTERIOR BUREAU OF MINES <br/><br/>
IMPROVING THE PERFORMANCE OF TUNNEL RAISE AND SHAFT BORING MACHINES FOR COAL MIN 

 - SPRINGFIELD  U.S.DEPT.OF INTERIOR  1986 
 - 29X23 
<br/><br/><label>Dewey Class. No.: </label>622.26 U58