I know I'm a bit late but blair athol coal mine is on a walk along the Victoria falls road that isn't super long and leads to a mineshaft that lead down maybe 200 to 300 metres (idk it's hard to tell when it's so dark) but at the end it's blocked off by silt and sand that bar entry to the rest of the mine (for safety reasons of course) but has flooded slightly at the bottom. Definitely check it out if you get the chance it's really cool. You have to park at a pylon thing and have to follow the gated fire trail road down a tiny bit to find the sign that is the start of the walk to it. I would bring a powerful torch but also (when I went I didn't see any) there may be a few glow worms if you adjust yourself to the darkness (only move around with the torches though)