Well, how deep can one go ? At one point it becomes logistically impossible to push air and ventilate a place that is too deep and it gets way too hot to sustain. Also, sustained bombing can eventually reach any depth eventually.
Remember that US attacks will not necessarily penetrate down to Fordow. Its in a mountain after all. even a volcanic eruption damages a small section of a mountain. The damage that GBU-57 will do will be via shockwaves that travel into the mountain and hope to create shafts which push the explosion inwards. US does not even know how many GBU-57s will be needed or even if they will work. the mountain might be good at absorbing the shockwaves, or the structure might be too tough for GBU-57s. even Us experts are not all agreeing on the success.
Anyway, the point being that you cannot make any subterranean facility that is 100% secure. If US wants to reach one, they can eventually reach it with sustained bombings. The question will be, how dangerous and risky can Iran make it for the US to deter them from doing it (Hormouz strait, ME Proxies, Missiles, US bases, etc ,etc). Iran can deter the US or make them regret their decision as soon as the US starts any such campaign. That will be the key to saving Fordow.
will prevail! Have no fear! Steel your hearts and don't listen to those spreading fear and doubt! They are servants of the LIAR!
