About this dropping water in the magma. What if you firstly cover the top with water so its all obsidian, then dig a nice hole in it, pour water, dig down, pour water, etc, till you reach the lowest level. Possible?
Falling rock doesn't stick to rocks right next to it. It also doesn't always fall straight down either, though it's rare and confusing when it doesn't. (Basically if you drop large enough chunks far enough down often enough you'll see some aberrations, eventually.)
But if the fresh obsidian has a rock wall next to it, then it could stick. I suppose it would, by default. I don't know for certain, as I haven't mixed the two, myself.
So it's probably possible to make a pier of obsidian out over the top of the volcano and then pour water down into it and hope that enough of it sticks together that it will form a spike down into the depths of the volcano.
But then you'd have constant problems with the formed obsidian clogging the water path on the way down, sending water where you really don't want it and perhaps blocking out the bottom or completely eliminating all the lava.
Every time the thing clogs itself good it's going to be a shaft filled with water and overflow over the top. Once the steam clears you'd have to build a pump-shaft down into the mess to get the water out, or extend the pump-shaft you built the time before. And only once the water is clear can you send dwarves down to clear out the clog.
Perhaps it would work better if started from the edge, though, and instead of building spike of obsidian down in the middle you built a wall out from the side. Then you could have your pump-tower run down through the rock on the outside of the volcano, and you'd just have to tunnel thorough existing obsidian to get out to the place where your water shaft is clogged.
It would be time consuming as you'd have to send down water shaft after water shaft.
Alternately, you could start at the edge and just keep moving further and further out into the lave each time you encounter a clog. This could be less time consuming, but you'd have to hope you got to the bottom before you go to the other side.
I'm going to call the top-down plan unfeasible under current game conditions. I'd love to be proven wrong.
Alright, new idea.
Put a cistern in at the bottom level of the map and make that its level. There should be no pressure, that is. You're going to need a lot of water down there, though.
Now you just have to Channel your way out into the lava. Itis going to cost you one dwarf for each time you breach the wall of the volcano, but it might work.
Author
Topic: Volcano Tower? (Read 2326 times)