text: Hot blast allowed the use of anthracite in iron smelting.  It also allowed use of lower quality coal because less fuel meant proportionately less sulfur and ash.	
  At the time the process was invented, good coking coal was only available in sufficient quantities in Great Britain and western Germany, so iron furnaces in the US were using charcoal.  This meant that any given iron furnace required vast tracts of forested land for charcoal production, and generally went out of blast when the nearby woods had been felled. Attempts to use anthracite as a fuel had ended in failure, as the coal resisted ignition under cold blast conditions. In 1831, Dr. Frederick W. Gessenhainer filed for a US patent on the use of hot blast and anthracite to smelt iron. He produced a small quantity of anthracite iron by this method at Valley Furnace near Pottsville, Pennsylvania in 1836, but due to breakdowns and his illness and death in 1838, he was not able to develop the process into large-scale production.
  Anthracite was displaced by coke in the US after the Civil War.  Coke was more porous and able to support the heavier loads in the vastly larger furnaces of the late 19th century.