Morrell, Roger J. <br/><br/>
Tunnel boring technology: disk cutter experiments in metamorphic and igneous rocks 
Morrell, Roger J.; Larson, David A. 
 - Washington  Bureau of mines  1974 
 - 50 p. 
 - RI 7961 .
<br/><br/><label>Subjects--Topical Terms: </label><br/>MINERIA<br/>MINING
<br/><br/><label>Subjects--Index Terms: </label>MAQUINARIA PARA LA INDUSTRIA MINERA TUNELES EQUIPOS Y SUMINISTROS MINING MACHINERY TUNNELING EQUIPMENT AND SUPPLIES 
<br/><br/><label>Universal Decimal Class. No.: </label>622