I've been playing on a survival world for quite a while now, started sometime back in early 2018 (it's actually the world mentioned here).
It's my most built-up world by far. My base/town has become so large I need two beacons. The ground under my base has been so thoroughly stripped of its valuables that I've had to go to all corners of my map just to begin new mines.
Point is, as far as my world's underground is concerned, I've been to and have seen pretty much all it has to offer, and I've not seen a single abandoned mineshaft. I know this isn't some game-wide bug, as I have many other survival worlds created through various points in the game's development and they all have them, some in abundance.
But this one - my main one - has not one. To confirm this, I've explored the tunnels of all my mines throughout the map (which are all at Y:11) and used the third-person camera sway to "peek," showing me surrounding caves and whatnot. No abandoned mineshafts.
I'm curious as to how common this is. This is the first time I've ever had this happen to me across all the platforms I've played the game on (PS3, 360, PS4, Xbox One before it was Bedrock). Have you ever had a world with no abandoned mineshafts?