The torch looks very nice (even though it's not animated, but I trust you to make it look great in motion too ), but what would be a really nice touch I think is a barrel with an oldskool lantern on it. Maybe you could even add an illuminated area around it (like with the Medivo torches), that would be very atmospheric.

I've always thought the mine in Lucky Luke (the game) looked great, maybe you've played the game or else these screenshots might be useful as inspiration: one two.

I love the theme, by the way. I think the only other mine-themed tileset that's really worth using is Violet's Mining Operation which, though large and with nice eyecandy, looks nowhere as good as your recent sets