So for the most part the mods seem fine even though they don't interact much (I kinda want to make my own patch at some point so you have to dig to the bottom of subsurface just to reach the underground.) But right now Vulcanus and Fulgora underground crash when I try to place a miner.

Do you have an error message for the drills? I can take a look if it’s a ST problem

Error while running event Subsurface::on_built_entity (ID 6)
Subsurface/scripts/resources.lua:114: bad argument #1 of 2 to 'pairs' (table expected, got nil)
stack traceback:
[C]: in function 'pairs'
Subsurface/scripts/resources.lua:114: in function 'copy_resource_data'
Subsurface/control.lua:210: in function 'get_subsurface'
Subsurface/control.lua:517: in function 'replace_surface_drill_dummy'
Subsurface/control.lua:572: in function <Subsurface/control.lua:560>

I've seen it in other modded surfaces. I think it happens whenever subsurface doesn't know how to build a linked surface.

Just as a heads up, there's a fixed script on the github for subsurface so it should be fixed on that end at some point.

Awesome, I will let that get fixed on their end. Thanks!