For anyone who has never built a pump stack, here is a short tutorial:
First, dig out a HUGE shaft, four tiles long and as wide as you want your pump stack (one tile for Iche_Bins, two tiles for me). The levels must alternate, with even numbered levels going floor-hole-floor-hole, and odd numbered levels going hole-floor-hole-floor.
Like this:
That way, there is a hole on the level immediately above every floor tile, and a floor tile on the level immediately above every hole. Except for the very bottom level, just above the Magma, which has no hole in the middle of the floor, only at one end.
It may seem crazy, but there is METHOD in my madness!
Then you start assembling your pumps.
ALL COMPONENTS MUST BE MADE OF MAGMA_SAFE MATERIALS.
Presumably you have pre-built all the components that you will need. Since I am building a double-wide pump stack about 150 levels tall, I will need enough components to build 300 pumps. That's 300 blocks, 300 giant corkscrews, and 300 tubes. I will be using Green Glass for ALL of the components (blocks, corkscrews, tubes), since it is Magma-Safe and consumes no materials to manufacture (only time and effort).
On every level that has a ledge on the left (and a hole on the right), the Pump is oriented to pump from right to left. On every level that has a ledge on the right (and a hole on the left), the pump is oriented to pump from left to right.
Like this:
So each pump is going to suck up the Magma that's sitting on the ledge on the level below, and shove it sideways onto the ledge on the pump's own level. Each blob of Magma gets passed like a bucket in a bucket brigade, going up one level each time it passes through a pump. Since this is happening on EVERY level of the stack simultaneously, the result is a steady flow of Magma out the top of the stack.
A final few details:
Pumps must be built on "solid ground", so the game won't let us build them over those holes. In the entire stack, only the pump on the very bottom level (with no hole under the Glass Block) can be built at first. But once THAT pump is built, the top of the Glass Block acts as "solid ground" for the pump in the next level up... allowing us to build the pumps, one at a time, starting at the bottom of the stack and finishing at the top.
If these holes in the floor force us to build the pumps one at a time (with each completed pump providing a stable working surface for building the next one up) instead of using a big work-force to build them all at once, you might wonder WHY it is designed this way?
It's because directly adjacent machines... and a pump is a machine, for game purposes... will pass power to each other without any need of external connections. And since each pump rests directly on the pump below (touching it, through that hole in the floor), we only need to connect the power feed to ONE of the pumps, and it will pass the power to all the rest.
Naturally, we still have to supply enough power to RUN all the pumps... but we don't have to distribute it to three hundred individual pumps. Just connect the power feed to ANY pump, and because they are all touching each other, they share out the power between themselves.
Any questions?