EDIT: Now with repeatability!
I recently did some dwarven science and I have a method for bringing magma up from the magma sea without using a (large) pump stack
Basically, you use the fact that cave ins displace liquids above them. If you carve out a long column of rock (refered to as the piston) and drop it into the magma, every unit of magma underneath will move to the top of the column. If you prepare a catchment area at the top, then it wont fall back down the shaft and you have yourself a nice pool of magma.
Reasons you would build one of these instead of a traditional pump stack:
- No fps drop
- Very little iron is needed. I moved magma up over 150 levels on a map with no iron ore or sand. The only magma proof pumps needed are to fill the cistern at the bottom and empty the reservois at the top
- Much less fiddly designating and managing production of components. Just designate it in one go and let the miners do their thing
- Very dwarfy
Heres an mspaint drawing of one before it was triggered
and one afterHere
is a map of my final repeating version.EDIT:
As someone has pointed out below, semi molten rock will eat the piston, so you can't drop it directly into the magma sea, and you'll have to use a cistern. To reinterate: DO NOT DO THIS DIRECTLY INTO THE MAGMA SEA. IT WILL NOT WORK
The hatches / retracting bridges are there to catch the magma without supporting the piston. Also make sure they are magma proof or you will have a problem (I made that mistake the first time round with some granite hatches). It's also important that you make sure they line up at the right level (or a bit below would aslo work).
I tested this originally using a tank filled by a volcano and transported a 14x10x5 volume of 7/7 magma (thats 4900 units) up around 20 z-levels.Things to remember
Making a repeatable pump
- Scout your location. Your pump can only be as high as its shortest z-column so you need to find a way down to the magma sea with as much natural rock as possible. Send military or feline explorers to map out the caverns for you and pick a good spot. Dig into the magma sea in a few spots to map its shape as well. Or use reveal.exe.
- If your piston has bits missing in the middle because of caverns, anchor the bottom section, and drop the top parts. The gaps will fill and you can then clean up the top of the piston
- Mine, don't channel. Channelling out the shaft takes a ridiculously long time and is dangerous for your miners. Just mine out the shaft and drop a floor from above when you are done to break through all the floors. You can mass designate the shaft by holding down the mouse and going up and down in long z-level columns. Designating 150 z-levels takes around 5 minutes, and digging takes less than a year with 3 miners
The method above will give you a big hit of magma, suitable for setting up your metal industry, pits for trash/goblins, and maybe a nice trap or two if you recycle it. If you want tons of magma to throw around everywhere you need a repeating pump, which takes a little more work than the one shot method.
The basic principle behind this is to cast obsidian on top of the piston. In order to gain magma, you need to minimise the amout of magma present when you cast. You'll need some bridges above the piston which can be filled with water, then dropped on the piston. Make sure the shape and size of the falling water matches the piston exactly (don't worry, it wont spread as it falls). You will also need a set of pumps taking the magma up to at least the level above the orignal height of the piston (if your piston drops 3 levels each cycle, you need to go up at least 4 levels), and a way of returning this magma to the top of the piston. The procedure goes like this: remove magma untill there is around 2/7 magma left on top of the piston (it will work with 1/7, but you run the very real risk of tiles evaporating at the last second and ruining the casting, which is very hard to fix). Then dump water. Now return magma until there is a 2/7 layer on top if the piston and cast again. Repeat as needed until the piston is rebuilt, then pump out all the delicous magma that is sitting on the sides of the piston. Now all you have to do is mine out the cistern at the bottom, refill it, and your pump is reset.More things to remember:
- Make sure the whole thing is subteranean if your map freezes. My map was frozen half the year and it was a massive pain in the ass, as the obsidian caster will ice up.
- Don't try and cast with a 2/7 layer on top of a 7/7. The water doesnt all fall together, and as the obsidian sinks it throws magma everywhere and the obsidian will not form a flat surface, ruining your piston
- Everything about this device's performance can be worked out in advance: how much magma will come up, how much is needed to rebuild, etc. Run through the numbers before you start building to make sure that there will be enough magma to rebuild. A thin piston will be able to rebuild less layers that a fat one, as a greater proportion of the magma will end up on the sides
- And for Armok's sake, get familiar with how cave-ins work before attempting this
Anyway thats my contribution to dwarven science. Hopefully it will be used to bring magma to dwarves in need everywhere.