00629nam a2200205 a 450000100060000000300080000600500170001400800410003103500190007204000260009104100080011708200250012510000200015024501170017025000170028726000390030430000330034350000210037665000260039769053BD-RjUL20211209081838.0170409s1914    enka          001 0 e   d  a(BD-RjUL)69264  aBD-RjULbengcBD-RjUL  aeng  223a622.33bKEP 19141 aKerr, George L.10aPractical coal mining :bA manual for managers under-managers, colliery engineers, and others /cGeorge L. Kerr.  a5th rev. ed.  aLondon :bCharles Griffin, c1914.  axi, 778 p. :bill. ;c20 cm.  aIncludes Indexes  aCoal mines and mining