The ultimate symbol of American democracy, Mount Rushmore National Memorial has presided over the Black Hills of South Dakota since its completion in 1941. The sculpture, depicting 18-metre (60-foot) effigies of presidents George Washington, Thomas Jefferson, Theodore Roosevelt and Abraham Lincoln, was designed by American sculptor Gutzon Borglum, who sadly passed away before the memorial was actually finished.
On a happier note, of the 400 workers involved in carving these iconic figureheads, none died during the mammoth undertaking – unusual for any construction of the time, let alone one involving dynamite and at such dangerous heights. In fact these workers even had to climb a mountain to get to work, but then this was during America’s Great Depression, a time when a lot of people were just thankful to have jobs.
A massive 90 per cent of the rock removed from the mountain was blown away using dynamite. The powdermen in charge of the explosives set different-sized charges in specific locations in order to remove exact amounts of rock.
So that’s the main structural sculpting taken care of, now for the less explosive techniques. Men were lowered down in front of the 152-metre (500-foot) rock face in bosun’s chairs, using thick steel cable. At the top of the mountain men in winch houses controlled and lowered the cables by hand. If they winched too quickly, the workers in the bosun’s chairs would be injured, and so call boys were employed to sit on the mountain edge and shout instructions to the winch men.
To sculpt the last 15 centimetres (six inches) of stone, drillers and carving assistants used jackhammers and a technique called honeycombing, whereby they bored holes very close together. This weakened the hard granite so that it could be finished off by hand and then the presidents’ faces were smoothed off using ‘bumping’ tools