Mining tunnels

I know there was a request for digging, to change Landscape and this goes in the same direction.

My Idea is to allow building a mine to harvest Iron, Copper or other Raw materials for enhanced Crafting.
Because of the balance,there is always the risk, that the complete mine will be destroyed by collapsing, so it makes no sence, to use it as a house.

How should digging work?
I have the idea, that you need a explosive first, to make the stone mineable with your pickaxe. If its normal stone, you will gather 1-2 Ore per Hit for 5 hits, after that this field is gone and you need a new explosive.
If you finde a vein, every hit should gather 20 Ore for 10 hits. If you secure your mining tunnel with wood/metal the chance that it will be collapse will be lower. The chance that a tunnel will collapse, depends on the Size of the mountain and the length of the tunnel.
Trigger for check will be every explosion in the mine or special events (earthquake for example). If a tunnel was destroyed its like it never exists before. Everything in the tunnel gets destroyed and you will have also no landscape change.

i like the crafting and the gathering via nodes, but i dont think we need a terrain mod on this game.

just add caves, that would be realy nice