Anthracite iron charcoal — long the fuel of preference for smelting and glass making, creating a decades long search for alternative fuels. By mid-1792 prominent Philadelphians had formed the Lehigh Coal Mine Company (LHCM Co.) to bring Anthracite to cities reachable via the Delaware River Valley, especially Philadelphia — the nation's largest and most industrialized city, though no one fully understood how to use anthracite as a sole fuel—just that "it 'could' burn 'some' of the time" with a hot enough base fire, so could augment furnace fuels. The LHCM Co. had great difficulty getting many ark-loads of coal to the docks
Anthracite times been futile, and several such combustion areas exist today. The existence of an underground combustion site can sometimes be identified in the winter where fallen snow is seen to be melted by the warmth conducted from below. Proposals for harnessing this heat as geothermal energy have not been successful. A vein of anthracite that caught fire in Centralia, Pennsylvania in 1962 has been burning ever since, turning the once-thriving borough into a ghost town. Among current producers, Russia, China and Ukraine have the largest estimated recoverable reserves of anthracite. Other countries with substantial reserves include Vietnam and North Korea.