Krech, Warren W. <br/><br/>
A standard rock suite for rapid excavation research 
Krech, Warren W.; Henderson, Frank A.; Hjelmstad, Kenneth E. 
 - Washington  Bureau of mines  1974 
 - 29 p. 
 - RI 7865 .
<br/><br/><label>Subjects--Topical Terms: </label><br/>MINERIA<br/>MINING
<br/><br/><label>Subjects--Index Terms: </label>EXCAVACION MECANICA DE ROCAS EXCAVATION ROCK MECHANICS 
<br/><br/><label>Universal Decimal Class. No.: </label>622