Proceedings of the symposium on the use of diesel powered equipment in underground mining, Pittsburgh, Pa., Jannuary 30-31, 1973. 
U.S. Bureau of mines. 
 - Washington  Bureau of mines.  1975 
<br/><br/><label>Subjects--Topical Terms: </label><br/>MINERIA
<br/><br/><label>Universal Decimal Class. No.: </label>622(063)