>>508627642 (OP)>>508629521>>508630360https://www.history.navy.mil/research/library/online-reading-room/title-list-alphabetically/b/bunker-busters-robust-nuclear-earth-penetrator-issues.html
"The United States has one type of nuclear earth penetrator, the B61-11 bomb, which was accepted into the stockpile in September 2001.1 That weapon, though, according to an article by several scientists from Los Alamos National Laboratory, "cannot survive delivery into certain types of terrain in which such [hardened underground] facilities may be located."2 "
If you could somehow make a MIRV robust enough to survive the impact into deep soil or solid rock, and then explode right above the underground chamber, then you'd have a chance. But the consensus is that if you build a bunker deep enough under a tough mountain, the best you can do is collapse the tunnels you know about, but you won't be able to destroy the facility from the air.