Volume 2 describes basic mining techniques and production operations associated with underground bituminous coal mining. The report covers conventional mining, including undercutting the face, drilling, shooting the face, loading and hauling the coal, and supporting the roof; continuous mining, including use of the continuous mining machine, hauling the coal, and supporting the roof; and auger mining. Charts and illustrations depict the style of mining employed and its basic operations, the mining cycle involved, and the equipment and crew work cycles and their work elements. The report covers work element times for the various categories of seam height, production tonnage, and mining style. Work elements commonly subject to hazardous exposure are noted for each cycle along with a percentage estimate of the total cycle time subject to such exposure. Both parts of OFR 4-72 are available for reference at Bureau of Mines libraries.