The linked article contains some info pertinent to the allusion we made in our previous email, re: volcanoes 1-vs. atomic blasts/surface fires, etc.
"Of all the MX ballistic missile deployment concepts, perhaps none was as elaborate as deep basing. In this concept, peacekeeper missiles were to be transported by rail through an extensive maze of rock tunnels. The tunnels were deep enough to protect the missiles and support facilities from the direct hit of large nuclear bombs. After attack, tunnels or shafts were bored to the surface and the missiles could then be launched. (Emphasis added, since that's where I fit in. Even though the missiles were deep enough to survive attack, it had to be expected the Soviets would still try to get at them, and the overburden would then be badly crushed/broken and very difficult to tunnel through. - JtM) Special Projects studied concept variations for several years during the eighties. The studies included tunnel excavation, mucking, and support systems; underground nuclear, diesel generator, and fuel cell power plants; and ice, water, and steam heat sinks. During these studies, tunnel facilities were characterized and construction cost estimates and schedules were prepared."
That's still published, and therefore public. Nowadays, even once-published RFP's related to the concept have vanished from the web - and pretty much everywhere else.
I know why that's so, but must leave the explanation to your imagination. The Soviets figured it out, though - and I honestly believe that's one good reason they're no longer Soviets. You might say I helped underline the Assured in MAD.
In any case, some thought was given to what the atmospheric/climatic effects of blast ejecta would be if the Soviets did try to "root" the deep-based ICBM's out with big "bunker buster" nukes. It was more like a volcano than even a very, very major surface fire - but still not in the same league with Vulcan.
Does all this help?