Here's a closeup of the inside of the mine shaft. The Sperry-Iverson mine has an interesting tale.

"This mine was created in 1895 by miners A.D. "Dick" Sperry and Andrew Iverson. According to local lore, it was going to be "salted" with ore close to the ground, then sold to an unsuspecting buyer. The shaft goes down only 30 feet. No ore was ever removed from here. "
Armchair Tour of the Mountain Loop Highway