[Goose]

I offer this article from NPR on the bombs we dropped and their damage. I always felt that the earth overlying the target would always limit the penetration of the bomb. Finally I found some discussion and actual math regarding this. Worth a read.
https://www.npr.org/2025/06/25/nx-s1-544...ear-target

Good link. BC had a good one as well. As the article states, the composition of the earth above the target has a big effect on how deep the bomb will penetrate. I am guessing the USAF planners were well aware of the problem. What they may not know is the exact composition of the mountain. It would appear that even best case the maximum penetration depth of 60 meters is well short of the known depth of the operational "cave". Targeting the ventilation shafts may have dramatically increased the penetration depth, depending on their dimensions and whether there are right-angle path changes acting as anti-blast baffles in the ventilation shaft path. If the USAF actually had drawings of the site these questions may have answers. If they didn't, it is a lot of guesswork.
 
Another factor that has not been considered is that the Iranians created a large cave inside the mountain. While the shock wave from a blast may not travel well in solid rock, when such a wave hits the air interface of a cave the ceiling of the cave may spall off considerable material or even collapse. That could indeed destroy or damage what is inside the cave. The mining method called "block caving" relies on this progressive ceiling collapse. Multi-level mines have also come to grief due to shock waves from one tunnel blast collapsing a different another tunnel that was quite distant from blast. The only way to know how much damage was done it to actually look, and nobody can do that right now.
 
IMO if the question of how much damage was done actually matters, the whole evolution has been a failure. If Iran is willing to give up any aspirations of enrichment of uranium, the damage doesn't matter. If they aren't, the "problem" may be delayed but it is not removed.

[Goose]

I offer this article from NPR on the bombs we dropped and their damage. I always felt that the earth overlying the target would always limit the penetration of the bomb. Finally I found some discussion and actual math regarding this. Worth a read.
https://www.npr.org/2025/06/25/nx-s1-544...ear-target

Good link. BC had a good one as well. As the article states, the composition of the earth above the target has a big effect on how deep the bomb will penetrate. I am guessing the USAF planners were well aware of the problem. What they may not know is the exact composition of the mountain. It would appear that even best case the maximum penetration depth of 60 meters is well short of the known depth of the operational "cave". Targeting the ventilation shafts may have dramatically increased the penetration depth, depending on their dimensions and whether there are right-angle path changes acting as anti-blast baffles in the ventilation shaft path. If the USAF actually had drawings of the site these questions may have answers. If they didn't, it is a lot of guesswork.
 
Another factor that has not been considered is that the Iranians created a large cave inside the mountain. While the shock wave from a blast may not travel well in solid rock, when such a wave hits the air interface of a cave the ceiling of the cave may spall off considerable material or even collapse. That could indeed destroy or damage what is inside the cave. The mining method called "block caving" relies on this progressive ceiling collapse. Multi-level mines have also come to grief due to shock waves from one tunnel blast collapsing a different another tunnel that was quite distant from blast. The only way to know how much damage was done it to actually look, and nobody can do that right now.
 
IMO if the question of how much damage was done actually matters, the whole evolution has been a failure. If Iran is willing to give up any aspirations of enrichment of uranium, the damage doesn't matter. If they aren't, the "problem" may be delayed but it is not removed.