Annual report on mining activities / 
Commonwealth of Pennsylvania, Department of Environmental Resources. 
 - Harrisburg :  The Department of Environmental Resources,  1986. 
 - 536 p. 
<br/><br/><label>ISBN: </label>0818200960 
<br/><br/><label>LCCN: </label>90064024 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Coal mines and mining--Statistics--Periodicals.--Pennsylvania