00594cam a2200157Ii 4500001000800000005001700008008004100025040001500066100002300081245005600104260008300160300001900243490005500262650003700317830008200354455123920090128171526.0801110s1973 wvu 000 0 eng d aOCoLCbeng1 aLeonard, Joseph W.10aResearch needs in coal mining /cJoseph W. Leonard. aMorgantown, W. Va. :bCoal Research Bureau, West Virginia University,c[1973?] a9 p. ;c28 cm.1 aTechnical report - Coal Research Bureau ;vno. 100 0aCoal mines and miningxResearch. 0aTechnical report (West Virginia University. Coal Research Bureau) ;vno. l00.