...or, how I learned some important things about mining after the job priorities release.
Back in the days of legend, or so I'm told, it was possible for a legendary miner to dig straight down through an aquifer and literally outrun the water. But even if that's no more than a fairy tale for young dorflings, I know from experience that it was possible back in the v34.11 days to dig through a couple of layers of aquifer this way. And that led to the elegant little technique described
in this thread. An aquifer pierce that doesn't require any wood or opening to the surface sure is handy on an evil biome, after all.
So recently I tried this again in v43.05, and failed miserably at first. As it turns out, the job priorities release (40.23 or so) broke the "chicken run" technique. What used to happen was, you would designate a vertical shaft of up/down stairs. The miner digging down would reveal damp stone and then: 1) the game would pause and recenter, with the mining designation canceled, 2) before unpausing you would redesignate the damp tile for digging, and 3) upon unpausing, the miner would immediately start digging the damp tile. If the dorf was fast enough, the next layer of stairs would be done before the water reached 4/7 deep, the water would fall to the level below, and the miner would be left standing on a dry tile in the aquifer layer. (If you wanted go deeper, you would then clear out an area of the top aquifer surrounded by drains and do it again.)
What happens now is, 1) the pause and cancellation happens as before, but 2) the miner is left in "No Job" status, 3) lacking a job, the miner wanders off, and 4) by the time the job system reassigns the miner to mine, the shaft has flooded and the tile you wanted to dig out is inaccessible. However, I saw a post (sadly I've lost the link) that mentioned in passing that channeling still works. And lo, it does! The trick is to dig downward stairs above the aquifer first, so all the tiles you want to dig are already revealed as damp. Then dig an up/down stair into the aquifer, pause once the job is in progress, and designate an adjacent revealed tile for channeling. In my testing, channeling (which removes two tiles of material) takes exactly the same number of ticks as mining or carving stairs. Thus, a level 9-10 miner can pretty consistently pull it off. And with that minor tweak to the procedure, I got the plugging method working again. Yay, no undead keas in my fort!
I've
updated the wiki accordingly.