The Ruggles mine was in operation for over 200 years.   Their claim to fame is being the Oldest and Most Spectacular Mica, Feldspar, Beryl, and Uranium Mine in the USA.  As a sense of perspective, compare the size of the people to the tunnel.





And the mica glints in the sun, while tourists pay to rent a hammer, buckets and goggles to get souvenirs from what was a viable commercial mine, until it became cheaper to import mica from overseas.