Tunnels and Shafts in Rock/ 
Department of the Army U. S Army Corps of Engineers 
 - Washington :  Department of the Army U. S Army Corps of Engineers,  1997 
 - various Pages  ill. ;  30 cm 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Tunnels and Rock
<br/><br/><label>Dewey Class. No.: </label>624.193 TUN