This is a Real Photo Post Card. The paper was made by Ansco of Binghamton NY. The trademark is CYKO. That trademark seems to have been discontinued in 1928, when Ansco merged with Agfa.
I acquired this card in East Tennessee from an individual who also didn’t know where it was, but was sold to me on the basis of the railroad stuff in the picture. I figured I could work out where it was. But I’ve had no luck. These places came and went fairly quickly in the early days of commercial coal mining.
Blogging the Railroad Tunnels 