That image... my God...
Thoth, ShdwFlm, thanks for your work on that!
The first step towards getting this thing mineable, is getting it playable. There's several thousand empty z-levels above the top of this thing. If we could cut all but 15 of those z-levels off, somehow, it might make the map a little more FPS-friendly.
The next step should be figuring out why these dwarves will make tools and move tools to stockpiles, but won't actually equip them in order to use them outside of military purposes (they did pick up stuff when told to do so as a military squad, but they dropped them as soon as their orders were cancelled or they went inactive).
Once we can trim some z-levels off and get dwarves to at least pick up their tools, mining should be no problem since they already can smooth the walls of the spire and carve fortifications to it i.e. they know that the spire is there, they know they can path to it, and they are able to work on it.
Since everything I've heard about this map so far implies that Windows users are unable to run it (due to crashing), getting these steps would require someone running the game on Linux (possibly 64-bit Linux, specifically) and poking around in the RAM while the game is running, comparing things that are or are not happening with things that should or should not be happening when the game runs normally. And that's waaaay out of my league.