Cleaning Mount Rushmore
Kärcher, in cooperation with the National Park Service, were comissioned in 2005, to celebrate the Independence Day, to clean the presidents’ heads on Mount Rushmore in South Dakota. The restorative cleaning work was carried out as part of a culture sponsoring project. The aim of the project was to remove lichen, algae, moss and other organic stains that could damage the underlying rock by way of bio-corrosion. The cleaning kicked required a little more than three weeks to complete.
Sculptor Gutzon Borglum and 400 workers carved the giant heads of American Presidents George Washington, Thomas Jefferson, Theodore Roosevelt and Abraham Lincoln between 1927 and 1941. They are about 60 feet high and, along with the Statue of Liberty in New York, probably the best known monument in the United States.
In words of Borglum:
“A monument’s dimensions should be determined by the importance to civilization of the events commemorated. We are not here trying to carve an epic, portray a moonlight scene, or write a sonnet; neither are we dealing with mystery or tragedy, but rather the constructive and dramatic moments or crises in our amazing history.”
The cleaning was performed purely with water, without any chemical additives. Five diesel-powered Kärcher hot water pressure washers cleaned the granite surfaces with rotary nozzles. The use of hot water will delay any recurrence of growth on the rock sculptures. A team of three highly qualified rappelling professionals descends from the top of the Space Needle, using only very hot water shot from high-pressure washers as they go. A rope-access safety supervisor mans the ropes and rappelling equipment from above.
As an anecdotic quote, Minister Nicolas Sarkozy has refered to this kind of cleaning works in 2005, when he remarked during the riots in inmigrant neighborhoods in Paris, that rioters ought to be “kärcherized”.