Never the less I experimented with local copies of the mine and thought it might be usefull for others or interesting to play with the concept of a mine as schematic file.
This is what the building should look like once it is put in place as intended.
To achieve this unzip the schematic file towermine2.we into a schems folder of your world. Once you have the WE priviliges go to the southwest corner of your construction site, stand on the level intended for the entrance and type //pos1 into the chat console. You might want to fly about 200m up and 100m down now (type h to use noclip for flying down) to make Minetest load the chunks the building will be generated in.
Now type //load towermine2 into the chat console. The building will be generated to the north and east of pos1 and as for now all above ground. Next go to the diagonal opposite corner of the building and place your avatar on exactly the opposite corner of the stone structure. Now fly exactly upwards only. Once you are higher than the glass spire tip, type //pos2 into the console. Now comes the tricky parts. To force the open spaces to not be filled with underground nodes we will replace them. Type for example //replace air papyrus to fill all air in the selected area with papyrus. You should have a pretty green building now.
To move the building underground now type //move y -100 into the chat console and after the building has regenerated finish by typing //replace papyrus air into the chat console.
Now you can wander down the stairs and start mining the exposed walls. If you place the structure through some lava lakes these will now spill into the building, so have some glass handy for spectacular windows.
It might be advisable to try placing the building on an extra map first to get an idea of how WE works. There is no easy way back and you may destroy a map if it does not work as you planned.
Floating in the sky you can see the dimensions of the whole structure. In the front you can see what happens if the mapgenerator wants to join the fun and adds some caves and dirt to the building. Preloading the chunks including the air of the area you will work in may help to stop this happen.
The tower and the mine are still very much as build on the server so expect some design changes as in the top two levels of the tower and expect ores all over the place as most of the underground was dugout and not built. I have changed the entrance level a little as on the server it is underground and one side is unfinished as it is protected area of someone else. No extra mods should be needed for this building.
have fun
