Elements of practical coal mining / 
Douglas f. crickmer, David a. zegeer eds. 
 - 2 
 - 847 páginas 
<br/><br/><label>ISBN: </label>0895202700 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Huella--Minas y mineria
<br/><br/><label>LC Class. No.: </label>TN802  / E45 1981