The U.S. state of Pennsylvania is known for many things. Among them is coal mining. Although there are many coal mines in the state, some of them are no longer active. Among them is the Number 9 Coal Mine in Lansford.

Opened in 1855 by the Lehigh Coal and Navigation Company, Anthracite coal was mined and dug out from multiple veins of which one of them is called the Mammoth Vein which was nearly 100 inches thick in some places. (In case you are confused, a vein of coal is an underground area where coal is dug out or extracted from.) It was at the time the longest continuously operating Anthracite coal mine in the world. The mining stopped on June 22, 1972. The mine was abandoned. In 1992, the Panther Creek Valley Foundation reopened the mine not as a working coal mine but as a tourist destination. It was…