There is no public information about what kind of material 60m refers to, and the best guesses of reinforced concrete are 18m. https://en.m.wikipedia.org/wiki/GBU-57A/B_MOP While a single bomb would be insufficient, you don't need that many to get to 80m.
And US military assets are often much more powerful than publicly advertised...
A bomb penetrating 18m of reinforced concrete doesn't excavate 18m of concrete. It would weaken it by some percentage through fractures and overpressure but you'll need to pen it again with the second bomb.
According to the pentagon briefing this morning they dropped 14. News is reporting that it was in 3 specific locations and they were dropped successively. Assuming most detonated successfully, that much specialized ordinance did some damage. This bomb was specifically designed for this very purpose and you have to realize that capabilities that are reported are probably pretty conservative vs what the bomb is actually capable of doing.
I know a bunch of armchair generals on here are speculating that this was ineffective, but time will tell.
Because it’s always the case with the US military equipment capabilities that full capability is never disclosed. What possible reason would the military have in divulging actual specs?
Military: We can penetrate up to 200 feet with this new bunker buster bomb that we spent a billion dollars on…specifically for this site and some sites in North Korea.
Enemy: Build the bunker at 300 feet, I hear their best bunker buster is only effective to 200 feet.
And US military assets are often much more powerful than publicly advertised...