I came across this article in Alert Diver magazine on the Bonne Terre Mine in Bonne Terre, Missouri.
Then I found this video excerpt from the History Channel’s trip:
The Alert Diver article boasts some really nice photographs from the mine which you can find in this gallery. The dive site seems like an awesome mix between Indiana Jones and Sanctum – all the good parts anyways. Cave diving in a flooded mine in the middle of Missouri sounds pretty cool. Cold water tends to preserve leftover equipment which means it’s probably great for photography.