NewsWomen's History Month


Breaking a glass ceiling of rock: Janet Bonnema was the first woman to work in Colorado's Eisenhower Tunnel

After winning a court case in the 1970s, Bonnema began her work in the tunnel, surrounded by men
Posted: 10:30 PM, Mar 07, 2023
Updated: 2023-03-08 20:16:36-05
Eisenhower Johnson Memorial Tunnel_Janet Bonnema.jpeg

Surrounded by an all-male crew high in the Colorado mountains in the 1970s, a young female technician proudly walked through the muddy bore that would become the Eisenhower Tunnel. She had smashed through a glass ceiling made of countless pounds of rock under the Continental Divide.

The Eisenhower Memorial Tunnel, named after former President Dwight E. Eisenhower, opened on March 8, 1973 after a ceremony inside the east portal. The second bore, named after former Governor and U.S. Sen. Edwin C. Johnson, opened in December 1979.


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More than 6,000 people were employed in the project.

One of them was Janet Bonnema.

Janet Bonnema
Engineer Janet Bonnema is overjoyed about gaining access to the Straight Creek Tunnel as part of her work in November 1972. Denver Post File Photo

Bonnema was born in south Denver in 1938. Despite her interest in math and science, counselors in school tried to guide her away from those subjects. She went on to earn a history degree from the University of Colorado in Boulder, where she was also the captain of the ski team.

Beyond her schooling, she lived life to the fullest. She was a rock climber, skier, parachutist, pilot and world traveler — breaking down gender stereotypes to pursue her passions, according to the Colorado Women's Hall of Fame.

The woman who made history engineering the Eisenhower Tunnel: Janet Bonnema

Bonnema, who lived in Georgetown at the time, placed fifth among people tested by the state as an engineering technician, according to a Nov. 9, 1972 article by the Golden Daily Transcript.

In November 1970, Bonnema reached out to the Colorado Highway Department — as it was called before it was renamed the Colorado Department of Transportation (CDOT) — about a job opening as a technician for the Eisenhower tunnel project. The project had started in March 1968 and was set to finish by March 1973. And she wanted in.

In April of 1976 workers continue on the second bore of the Eisenhower (Memorial) Tunnel. Denver Post File Photo

Bonnema had met the qualifications and passed the required tests, according to the U.S. Department of Transportation. After 18 months as an engineering technician, she had never been inside a tunnel before and was eager to explore the opportunity.

On Dec. 11, 1970, she received a letter from the department.

It read that "Mr. Jamet P. Bonnema" could accept the job if "he" wanted it.

"Someone had made a clerical error and thought that she was a man," said Lisa Schoch, cultural resources section manager and senior historian at CDOT headquarters. "I think someone wrote her name down as James... But, you know, I think it also is that there were certain jobs that women did back then. And being an engineer in a tunnel wasn't one of them."

When Bonnema reached back out to the highway department, a state employment officer advised her not to take the position.

Workers at the Eisenhower Memorial Tunnel inspect drilling platform after explosion an explosion that injured eight in September 1976. A miner on the middle level of three-level "jumbo" drilled into small amount of dynamite left unexploded in earlier blast on tunnel face, behind machine. Denver Post File Photo

"Women are taboo in the mines and tunnels of Colorado," he said, according to the U.S. Department of Transportation. "Those workers would flat walk out of that there tunnel and they'd never come back."

At the time, there was a long-standing belief that if a woman entered the tunnel while it was under construction, it would collapse.

The state department acknowledged Bonnema was "smart as a whip" but only offered her a drafting job in which she could never enter the tunnel. She accepted the position before filing a sexual discrimination lawsuit in 1972 against the Colorado Highway Department. In the lawsuit, she demanded $100,000 and the right to work in the tunnel, according to "Divided Highways" by Tom Lewis.

"I am not allowed to do the same work as the male engineering technicians, even though I am physically able, in better condition and have more stamina than many of the male engineering technicians," she told a reporter.

Her suit never went to trial — she won that battle in November 1972, when Colorado voters decided to amend the state constitution to guarantee equal rights for women.

In August 1968, workmen settle freshly poured concrete with vibrators in this section near the west portal of the Straight Creek Tunnel 15 miles west of Georgetown. Denver Post File Photo

"Her successful fight in court for her right to work inside the tunnel helped break down the centuries-old discriminatory myth that women in tunnels and mines would bring bad luck," the Colorado Women's Hall of Fame reported.

It was a win that, after two years, finally let Bonnema take her first muddy steps in the tunnel alongside a female reporter from The Denver Post on Nov. 9, 1972, according to the "Divided Highways" book and the New York Times.

But seeing a woman in the tunnel was too much for some men. The U.S. Department of Transportation reported that 70 to 100 men walked off the job. A 25-year-old man quit. Others complained it was a jinx to have a woman in the tunnel.

Bonnema did not stop.

"What's the matter with them?" she said as she walked around the tunnel.

The New York Times reported that men strapped high on the walls of the bore yelled to get the women out of the tunnel. But Bonnema "paid no attention" and "said that she thought the shouts were childish," the paper read.

The state estimated that the walkout cost about $10,000 at the time. Almost every single worker returned to work the following day.

Bonnema went on to do the job she was hired for, recording measurements, collecting samples and completing technical drawings, according to the Colorado Women's Hall of Fame.

Janet Bonnema
In November 1972, Rueben Hopper, state highway department district engineer, explained engineering aspects of the tunnel to Janet Bonnema. She qualified as an engineering technician for employment in the tunnel. Denver Post File Photo

Throughout the project, she turned plenty of heads as she rode up to the site every day on her motorcycle.

After the tunnel was completed, she earned her master's degree in civil engineering at the University of Colorado at Denver.

She retired from a water engineering job in Florida in 2001.

In 2008, she passed away at the age of 69 after a fight against cancer.

Bonnema's demands to work in the tunnel, and the subsequent court case, helped pave the way for more women to be employed to work in tunnel engineering projects, her obituary read.

Janet Bonnema
The Lady Is A Miner — Janet Bonnema (right) makes her way through the Straight Creek Tunnel. Bonnema, of Georgetown, Colo., was hired to work in the tunnel, but was sent to the division office instead of working in the tunnel. Janet filed a suit, charging sex discrimination against the Colorado Division of Highways. Bonnema was assigned as a rock mechanic, a Job which requires periodic trips into the tunnel. Shouting, "Get the women out of here” about 60 workers walked off the job. Credit: The Denver Post

Four years after her death, she was inducted into the Colorado Women's Hall of Fame.

Today, a photo of Bonnema hangs in CDOT elevator lobby.

"We've honored her in one of our elevator lobbies with a photo because she was, you know, a really important part of the story," Schoch said. "It's a small part of the story, right? It's not something that probably most people know about. But she was a trailblazer."

READ MORE: These are the repairs, upgrades expected at the Eisenhower Johnson Memorial Tunnel in 2023, 2024