Building a pump stack, all the way from the magma layer up to my fort, to have magma-powered forges and smelters running before I run out of coal. Which, I should add, was pretty soon, considering that it happened while I was making tons of iron pipe sections, iron corkscrews, and half iron blocks-half magma safe rock blocks. Guess I have to do the rest on charcoal. Luckily I have a huge abundance of wood. Sadly this means I have to suspend the production of iron pump parts until I have enough charcoal to resume.
I am done with the pump housing, and now I just need to dig a vertical shaft next to the housing to have axles. That's because the pump stack is not one large stacks, but because of the caverns I have to make turns. Good stuff... I need far more power now because of all the axles and gear assemblies. But the first time I built pump stack from the caverns (for water) I already made far too much windmills than necessary, generating 880 power when only needing 400 for the pumps.
What is funny is that I started digging the shaft three real minutes ago and it already claimed one life. Luckily not a very experienced miner. Seriously though, can't dwarves just dig straight down instead of periodically skipping one layer, and when someone else digs out that one, standing right under it so that the 3 falling rocks, each weighing 29.2 kg, will hit their heads?
Edit:
I looked it up because of my solid boredom. The formula for the terminal velocity without air resistance is terminal velocity = sqrt((2 x mass in g x acceleration due to gravity) / (density of air in g/cm3 x area of object x drag coefficent)). I took the drag coefficient to be that of a sphere, or 0.47.
That makes that the terminal velocity of a gabbro rock is sqrt((2 x 0.0292 x 2861.6) / (0.001225 x 21.5443469 x .47) = 116.071941. That's 417.8 km/h, or 259.6 mph. I think that's terribly incorrect, but since I have no idea what mistake I made in my calculation, I'm going to assume that that's it.