We cannot allow a mine shaft gap!
Similar to the book in the original Boing Boing post: Fallout Protection published by the Department of Defense’s Office of Civil Defense in 1961.
That pamphlet and a few other pamphlets on the same subject are available from the Nifty from the Last Fifty Initiative page on the Washington State Department of Archeology and Historic Preservation website under the heading Fallout Shelter.
