Map is inaccurate in scale in so far as the distance to the collapsed bit will take about 2-3 hours (and is a long way DOWN) but the straight corridoors are around 60ft long only (hey - that's what happens when you make a map with charcoal on a knackered piece of cowhide!).

The incomplete corridoors lead off into the rest of the mines - undoubtably filled with undead by now.....