Rushmore Faces Remain Solid

KEYSTONE, S.D. – The four presidential figures chiseled into Mount Rushmore may be getting a bit fidgety, but don’t expect any of them to bolt from their batholith anytime soon.
Observational data from RESPEC, a Rapid City, S.D.-based engineering firm, shows minute movement in the granite at Mount Rushmore National Monument, but it looks like a back-and-forth proposition.
The Associated Press reported that data from linear variable displacement transducers (LVDTs) attached to the heads of George Washington and Abraham Lincoln show some stone creep, from 5/100” to 5/1000”. However, it’s all related to temperature variations, and the stone keeps moving back to its original position.
Engineers with RESPEC note that the faces of the four presidents on Mount Rushmore – Washington, Lincoln, Thomas Jefferson and Theodore Roosevelt – are actually a series of 25-30 separate piece of work. Work done on the monument in the 1970s stopped a series of water leaks, and the hairline cracks tracked by the measuring devices admit very little – if any – water.
The 60’-tall busts of the four presidents took 14 years to complete, with the final dedication in 1941. The sculpted faces remain in better long-term shape that New Hampshire’s Old Man of the Mountains, a natural formation that fell earlier this year.