Quote from Uristqwerty
...list of epicness...
1. 3wide prepped stairs down to y=12.
2. cavemine all the caves encountered on the way down.
3. Dig out a long 3x3 tunnel at y=12
4. branch mine out of that with 2x1 tunnels with 3block separation.
5. switch to automated mining using the quarry options available in my modpack.