Cervik, Joseph <br/><br/>
Rotary drilling holes in coalbeds for degasification 
Cervik, Joseph; Aul, George N.; Fields, H. H. 
 - Washington  Bureau of mines  1975 
 - 21 p. 
 - RI 8097 .
<br/><br/><label>Subjects--Topical Terms: </label><br/>MINERIA<br/>MINING
<br/><br/><label>Subjects--Index Terms: </label>SEGURIDAD MINERA DESGASIFICACION DE CARBON MINE SAFETY DEGASSING OF COAL 
<br/><br/><label>Universal Decimal Class. No.: </label>622