AAI MINER when full disable digging mode, re-enable when empty

check ss seed 32 bit randompenalyty

do not stick to 10% richness decrase, make this randomly:
- per-surface property with level
- change the formula so each patch (or per-resource?) has different curve (x is level) - starting area always has 1.0 and no placement in subsurfaces
- adjust amount on chunk generation
- only for spot resources?

consider order for resource placement
do not place resources when there is none on oversurface (3 radius) - only for spot things, not those with their own probability-; they should be decreased in frequency according to water coverage

stone unrich in topsurfaces (decrease richness increase) (another multiplier expr.)
keep starting area richness at 100% (only top surfacse)

air vent speed + eff modules


top surfaces, no richness increase in distance, instead of general richness decrease (because starting area needs more)
digging demolisher
menu simulation when more popular
show camera when elevator or subway is in cursor
pole_links und car_links zusammenfassen?
air vents show pollution amount in description or stats. Also use quality
machine speed decrease with too much pollution
handle pollutant types (do not change type when transferring pollution between surfaces of different types): same pollution type; just wipe polution when oversurface has another type
machines are slower when too much pollution (needs invisible effect source per chunk) (alert)
super force build (rails) makes fake tile ghost to make robots dig (new empty-space similar tile, default_cover_tile)
when air vent is placed above non-exposed or underground is sealed underneath, show custom status. No placement cancellation
vent should be unaffected by effect sources (beacon)
vent does not stop venting - keep running - venting locale
enemies sense when digging underneath them (radius like 20 tiles). They will go there and dig down
split entities.lua/items.lua/recipes.lua into entity/item/recipe prototypes of each group separately, then check spaces between =

uran nur im untergrund
öl viel mehr und reicher
miners sehr langsam oben
high robot attrition
logistic/constr bots: only enable roboport if whole area is exposed. Or: roboports are replced by a clone without construction area. The area is created with smaller invisible roboports only where exposed 

dungeon keeper rooms quality products if only military recipes etc.

underground science pack
surface hole resoure different stage pictures, do not destroy when drill dies. New drills continue. create collision mask for that (like se core seam/real entrance). can be sealed
caveground changng graphics if alien biomes, not the autoplace, then remove grass from autoplace
support lamp on entrance/exit
enemies that fear light (min_darkness_to_spawn)
demolisher burries down
entrance/exit: left vehicle down (if there), right vehicle up, graphics both together, to dig further down a drill needs to be placed (with occupies exit)
wall mining should cost resources (and time), not per hand but a tool (like minecraft), maybe only by explosive?
mining time higher for more challenge, no robot mining (no mining in general, only explosives?), add a tunnel drill that drills in one direction (uses explosives, sulfuric acid etc) - belts in inventory which are placed behind it
noise expr. etc for rocks
wooden and iron supports (otherwise random collapses) - cant dig further if no support available. If explosion, then do a random collapse in certain radius. Supports cant be mined, if they die, also do a random collapse
uranium ore, better oil fields only in subsurfaces
underground not available under oil fields and water
Different textures for different subsurface levels (e.g., stone for the second level, darker textures for deeper levels).
unbreakable wall-Spots (biome patches) - check when placing drill if there is one underneath
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
informatron entries about resources and trains
rocket silos cant be placed above exposed underground and underground cant digged when there is a rocket silo above
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"
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
- electricity for fluid and item elevators
- some maintenance stuff (cables)
- lubricant, or sulfuric acid? (volcano)

Surface drill:
- create small holes and smoke while drilling (graphics_set)
- slowly clear subsurface randomly in given area, resource patch amount is reduced proportionally
- deeper( from lvl 1) drillings needs fluids
- lubricant as maintenance