Big Lick Tunnel
This is the south portal of Big Lick Tunnel, taken August 14, 2004. There has been heavy rain throughout eastern PA just days before, which may explain the high volume of water (apparently acid mine runoff) which was exiting the tunnel.
Note that on the 1955 USGS map shown above, the tunnel (and one other) are shown, abandoned, and by 1977 simply no longer appear.