there isn't room and what rock is there is not suitable for carving.
Then there's the mechanics and physics of it. There's no room, experts have said, and even if there were, the granite is not steady enough to take all the blasting that a new face would require.
that according to this article (by Bob Greene, whom if its the same, is a world class creep) - he adds that technology might allow it now, but we should consider Elvis instead:
http://www.jewishworldreview.com/bob/greene022301.aspBut if Mt. Rushmore wants to guarantee its success as a tourist attraction for centuries to come -- if it wants to see its attendance rocket beyond its caretakers' wildest dreams -- there is another American historical figure who might be added to the mountain.
Elvis Presley.
Don't laugh. Elvis has become an honored part of his country's saga in recent years. The tale of his life -- from humble beginnings to the greatest fame imaginable -- has reached almost storybook proportions. The unpleasantness toward the end of his brief 42 years has been forgiven many times over; the U.S. Postal Service has honored him with a stamp, which is just as mainstream a seal of approval as Mt. Rushmore. The face of Elvis is every bit as famous as the faces of Washington and Lincoln; the face of Elvis, 24 years after his death, is still the American face most instantly recognizable around the globe.
http://www.reaganlegacy.org/articles/nyt.02.11.01.htmsnip
Senator Johnson relied, in part, on Douglas A. Blankenship, a geomechanics consultant in Rapid City, S.D. When work began on Mount Rushmore in 1927 during the Coolidge administration, Gutzon Borglum, the monument's sculptor, had wanted to carve Jefferson to the left of Washington, Mr. Blankenship said.
But Mr. Borglum found the rock there too veined with cracks, said Mr. Blankenship, so Jefferson was carved to Washington's right, where the ground was more stable. Indeed, Mr. Borglum had to peel away nearly a half-million tons of crumbly granite to get to the more solid granite beneath.
What's more, there is not enough room to carve another 60-foot-tall, 30-foot-wide presidential head on either side. "Politics aside, this is the most asinine thing I've ever heard of," Mr. Blankenship said. "Do they want to put another head on Michelangelo's `David'?"
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