very interesting. i have some thoughts for tunnel projects myself, but how do you deal with iron veins in your way ? we're right south of there in North Laketown, if you need a hand, or want to sell off some stone.
You get 5 characters online, open the console and... bind space mine_up
Then bash the living daylights out of the keyboard, click the next client, bash again, repeat until all 5 actions queues are full. When you need more space to mine, drag the ore into the waiting pre-lit forge and bash again. When the forge is full of lumps, drag them to a waiting bsb.
Works with all veins, apart from slate and marble, and possibly sandstone if they fix it. It's also handy to have a crate of logs to keep the forge lit for the few hours it takes.