Energy resources and excavation technology  
/ Proceedings 18th U S Symposium On Rock Mechanics Held At Keystone, Colorado June 22-24, 1977 Sponsored By The Colorado School Of Mines With Cooperation From U S National Committee For Rock Mechanics 
 - Colorado:    Colorado School Of Mines Press,   1979 
 - xxiii, 5A5-6p. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Proceedings
<br/><br/><label>Universal Decimal Class. No.: </label>620.91:624.133  / L7