Larson, David A. <br/><br/>
Large-scale testing of the ripper fragmentation system / 
by David A. Larson, Roger J. Morrell, and David E. Swanson. 
 - Pittsburgh, Pa. :  U.S. Dept. of the Interior, Bureau of Mines,  1987. 
 - 18 p. :  ill. ;  28 cm. 
 - Report of investigations ;  9123 .
 - Report of investigations (United States. Bureau of Mines) ;  9123. .
<br/><br/>Bibliography: p. 16. 
<br/><br/><label>LCCN: </label>87600010  
<br/><br/><label>Subjects--Topical Terms: </label><br/>Drag bits (Drilling and boring)--Testing.<br/>Rock mechanics.<br/>Quarries and quarrying.
<br/><br/><label>LC Class. No.: </label>TN23  TN281  / .U43 no. 9123 
<br/><br/><label>Dewey Class. No.: </label>622 s  622/.23 
<br/><br/><label>Gov. Doc. Class. No.: </label>I 28.23:9123