This is a downward-extending branch consisting of 8 or 9 levels; it is reached by a second downstair in the Dungeons of Doom, between DL 2 and DL 4. If the top level is at DL 3, it is ineligible to leave bones due to its depth; otherwise, all levels except Mines' End may leave bones.
The following special levels are found in this branch:
| Minetown | (3rd or 4th level, DL 5 to DL 8) |
| Mines' End | (Bottom level, DL 10 to DL 13) |
All non-special levels are caverns, containing 7 gnomes, 2 dwarfs, a gnome lord, 2 random G and one random h. (However, note that if you are playing a dwarf or gnome, two-thirds of these dwarfs or gnomes respectively will be made random monsters instead.) 6 random traps are placed on each level, along with one random tool, 3 random loose gems (or piles of gems), and three random other objects; in addition, the rock is more heavily mineralised than the Dungeons of Doom. Monster creation in this branch is biased towards lawful monsters.