Since the 1950’s, the US Government has had nuclear powered tunneling machines. They were patented in the 1970's (US Patents #3,693,731). As it burrows through the rock hundreds of feet below the surface, the Subterrene heats whatever stone it encounters into molten rock, or magma, which cools after the Subterrene has moved on. The result is a tunnel with a smooth, glazed lining, somewhat like black glass, which is also apparently strong enough that it doesn’t even require reinforcing of the walls. It was featured in OMNI magazine, Sept 1983, p80.

I happened to see a picture of (what I assume is) one of these machines in a UFO magazine, but at $15, I wasn't going to (let alone couldn't afford to) buy it. Then I was visiting a friend and he showed me the wierdpics.com website, and lo and behold, there was the picture. Hmmm, what would the US airforce be doing tunneling deep under the ground?

The whole story here

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