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Science

Rope team rappels down Mount Rushmore to help preserve monument

 The Rope Access Team scales down Mount Rushmore
Kevin Steele
/
National Park Service
The Rope Access Team scales down Mount Rushmore

Recent visitors to Mount Rushmore were surprised to see more than four faces on the granite monument.

“There’s somebody up there ! It’s like wow, this is pretty cool, I’ve never seen that before," Darrell Bohnhoff said with a laugh.

Bohnhoff used binoculars to track the activity from the main plaza last week. He grew up in in southwestern North Dakota where his parents took him on trips to see Mount Rushmore. He now lives in Washington State but still makes time to visit the monument.

“This is my first time back for a few years, but this is my fourth time up here in about the last four days," Bohnhoff said. "First time I’ve ever seen workers dangling over the edge and that was pretty cool. It was like ‘oh my gosh, somebody’s up there and it gives you a real perspective.'"

 Four people work on and above President Lincoln's head
Michael Zimny
Four people work on and above President Lincoln's head

That perspective reminded him just how huge the monument is.

"Because I know that the faces are 60 feet, the noses are 20 feet," Bohnhoff said. "But to actually see the workers up there, live, instead of just in a picture is pretty neat.”

The workers are part of Mount Rushmore’s Rope Access Team. The group hiked up the back of the monument and rappelled down its face to calibrate sensors that monitor rock movement.

The monument has 22 areas called "rock blocks." That’s when multiple cracks combine, splitting a section of the rock face. Rangers have been monitoring four of the rock blocks since 1998. Two of them could potentially fall out of the sculpture.

Mount Rushmore Rope Team 4
National Park Service

"It’s hard to describe" being up there, team member Blaine Kortemeyer said as he looked up at the mountain he just came down from.

"One of my favorite places is across Jefferson," said Kortemeyer, who is also the acting chief of interpretation. "His gaze is actually four-degrees higher than the other three because of cracks during the carving era that (sculptor Gutzon) Borglum and workers had to adjust to. So putting the ropes right through Jefferson's part and hopping off the forehead across into the front of the eyes is pretty cool. I've only backed out on the nose once, it's kind of scary."

Kortemeyer, who’s six-feet tall, said he could stand on Jefferson’s bottom eyelid and reach up to touch his eyebrow.

 Blaine Kortemeyer, acting chief of interpretation and a rope team member at Mount Rushmore
Michael Zimny
Blaine Kortemeyer, acting chief of interpretation and a rope team member at Mount Rushmore

The team’s mission is to calibrate the sensors. They monitor how much the rock blocks shrink and expand with daily and seasonal temperature changes.

“The first study on the granite that is Mount Rushmore was done by Gutzon Borglum and the School of Mines and Technology right here in Rapid City," Kortemeyer said. "They estimated that the granite weathers at a rate of one inch every 10,000 years. So you know, granite's pretty durable, right. But it's not about the granite, it's about the cracks in the granite."

The good news is that the rock blocks are changing the same rate each year. The one that moves the most moves 44/1,000ths of an inch, or the width of a nickel.

Mount Rushmore Rope Team 7
National Park Service
A sensor on Mount Rushmore

Kortemeyer said he will start to worry if the rock blocks start shrinking or growing more than usual.

Water is the sculpture’s biggest enemy. When water in the cracks turns into ice, it can then push the blocks around.

“Well these rock blocks are huge," Kortemeyer said. "One is the upper third of Lincoln’s face. So they are monstrous. Who knows how much, how many tons they weigh."

Workers maintain the sculpture with silicone to seal cracks along the tops of the presidents’ heads and Washington’s left shoulder. Vertical cracks are left open to drain water on their own.

Mount Rushmore Rope Team 6
National Park Service
A sensor monitors a crack on Mount Rushmore.

But if regular maintenance isn’t enough, Kortemeyer said, workers could secure unstable rock blocks to the back side of the monument.

The rope team has about a dozen volunteers who also work at Mount Rushmore. They include park rangers, law enforcement and maintenance staff.

The group trains year-round but not on the monument itself. So the climbers spent a day training on the granite before taking a second day to calibrate all of the sensors.

The top of the mountain — called Tunkasila Sakpe Paha, or Six Grandfathers in Lakota — is not flat. So as they walk toward the edge, team members wear helmets and full-body harnesses with ropes and carabiners connected to a safety line.

Team members then connect two ropes to anchors before rappelling down the face of the monument.

They use descenders and ascenders to navigate up and down the working rope, plus a device that automatically locks onto the safety line if it notices rapid movement.

Blaine Kortemeyer wears a chest descender while demonstrating how his handhold descender works.
Michael Zimny
Blaine Kortemeyer wears a chest descender while demonstrating how his handhold descender works.

“Being on a two-rope system is actually safer than driving to work, statistically," Kortemeyer said.

It’s also safer and less cumbersome than the way workers navigated as they carved Mount Rushmore. Back then, workers strapped into a device called a bosun’s chair that was suspended from the rock face.

"The 3/8ths-inch cable goes to the top of the mountain, over the access ledge and to a two-person, hand-operated steel winch that has camming in it, gearing in it, so that you can lower and raise people," Kortemeyer said.

 Gutzon Borglum (left) and two other sculptors sit in bosun's chairs as they work on Mount Rushmore. The chairs are connected to chains and lowered and raised using a winch.
Charles D'Emery
Gutzon Borglum (left) and two other sculptors sit in bosun's chairs as they work on Mount Rushmore. The chairs are connected to chains and lowered and raised using a winch.

Today’s climbers control their own movement. And if they need to communicate, they use walkie talkies.

Back in the day, it was more like a game of telephone.

“The call boy sat out on the edge of the rock, yelled back and forth to tell the winchmen what the person in the bosun's chair needed to do," Kortemeyer said.

 This hand-operated winch is connected to steel cables that lift and lower workers in their bosun's chairs.
National Park Service
This hand-operated winch is connected to steel cables that lift and lower workers in their bosun's chairs.

Back at the main plaza, tourists watched the work on the monument. Fermin Cruz lives in in California and was surprised to see someone climbing around Lincoln’s forehead.

“I’ve never seen that before," he said. "Because I’m scared of heights, so I’m looking up, ‘please don’t fall down.’ But I’m glad they’re doing some touchups and whatever needs to be done so we can conserve for the future generation.”

Visitors will have to wait another year to watch the rope team conduct its annual calibration. The crew only returns if the sensors or cracks are in need of repair.