todo.txt

wooden and iron supports (otherwise random collapses)
uranium ore, better oil fields only in subsurfaces
underground not available under oil fields and water
seal tunnels and entrance by filling up with stones
Different textures for different subsurface levels (e.g., stone for the second level, darker textures for deeper levels).
unbreakable Rock-Spots (biome patches)
Rocket silo construction, stage 1 clears subsurface
rocket-silo needs drilling (like RSC but not that much)
find abandoned shelters (as secret) but with sealed entrance from above
smoke in polluted chunks
rocket silos cant be placed above exposed underground and underground cant digged when there is a rocket silo above
wall mining should cost resources (and time), not per hand but a tool (like minecraft), maybe only by explosive?
support for https://mods.factorio.com/mod/AbandonedRuins
Biters https://mods.factorio.com/mod/Subsurface/discussion/65cd6a8f4294e70fb2eeaca3 dig to both exposed and unexposed (not really, spawn when players dig to them) chunks
biters are harder in underground
"minesweeper"
lgiht cone in entrances, reuse rocket silo graphics for hole
better tech and recipe cost
alien biomes integration (rocks and ground tiles), rock decals on the ground

Resources:
- areas of "hard" stone (or like minecraft, below layer 3)
- SE planets have no ores, they are all in the underground
- high! size and richness
- find possible patch candidates but also nulls


Elevators:
- vent and elevator placement requires boring
- Elevators should not be split into separate items, but rotatable (arrows in alt mode)
- Elevators should require setup in both places, similar to the underground belts and pipes
- requester/provider elevator
- electricity for fluid and item elevators
- item elevator throughput change (items/tick)
- some maintenance stuff (cables)

Surface drill:
- create small holes and smoke while drilling (graphics_set)
- slowly clear subsurface randomly in given area, resource patch amount is reduced proportionally
- reuse driller (create hole, but leave drill where it is) (it needs to be expensive then)
- deeper( from lvl 1) drillings needs fluids
- lubricant as maintenance