[Wow okay huge radio silence. I'll just update now okay. Not probably enough awake for updating but whatever.]
The campers managed to survive the first week with careful rationing of their limited supplies, getting some thirty kilometers from the fortress in the nightmarishly difficult cavern terrain. Thick, oxygen-starved air, minimal light, thick underbrush, and uneven terrain make even this modest distance an impressive effort. Reaching a small lake, they set up a simple camp, consuming the last scraps of their supplies and considering what of the surrounding cavernlife might be worth eating. The second week, they spend by the shores of this little stagnant pond, living off boiled water filtered through a sock, questionable wild mushrooms, and an unlucky small rodenty thing killed with a single musket ball.
A few hours work by the light of a foul, hissing campfire produces a simple crossbow. The thing proves almost comically ineffective, and the bolts are pretty much sharpened bits of dead woodlichen, but it's reasonably functional, mechanically.
After some discussion, the Observers put forward their most knowledgeable occultist, both to review the Magus' reports, and to receive what training can be given. The dwarf seems fairly competent, and his decorated amulet suggests some kind of university ties.
The prototype thaumtech motors, while not directly useable as generators, could be used easily to upgrade the elevator's extremely inefficient basic model, and the gained knowledge could readily be applied, if in reverse, to improve the generator researchers' work. Additionally, the dam project has almost no construction equipment, all of it entirely hand-operated, and it would be the work of days to rig another of the prototypes to run one machine or another.
The dam foundation is almost complete, four huge blocks of stone held together and in place with steel girders rammed into the soft rock of the riverbed by a heavy spare anvil in the leverage of the makeshift crane. Secondary layers of smaller stones and perhaps concrete of some sort would be desirable, and this first layer still has water flowing over it, rendering construction difficult. Another worker was killed by drowning, and a second lost his arm to a snapped rope from the crane. The crew's spirit is waning further. Returning to the surface to be relieved by others would help them, but introducing further demoralized Serfs into the main fortress is not ideal.
The fabric effort has made reasonable progress, with some twenty square meters of fabric available for a project. With some effort, and a few innovations in the field of burners, this could be made into a small hot-air balloon easily enough.
Another cloud of dust is visible on the horizon! The dwarven caravan is due, so this is likely to be it.
After another few hours of waiting, this proves indeed to be the caravan. They reach the gates in early afternoon, a well-dressed dwarf with an Outpost Liason's medallion leading them.