Authorities rescued 12 people who were trapped for several hours underground Thursday after an elevator malfunctioned at a former gold mine that is now a Colorado tourist attraction.

At around noon, the elevator at the Mollie Kathleen Gold Mine near the town of Cripple Creek experienced mechanical issues that "created a severe danger for the participants," Teller County Sheriff Jason Mikesell said at a news conference earlier Thursday. Individuals who were part of a tour group were then trapped at the bottom of the mine, which is about 1,000 feet deep.

State and local authorities responded to the incident and were able to initially rescue 11 people, including two children and four people who sustained minor injuries, with a trolley system. The remaining 12 people, which included an employee of the mine, were stuck at the bottom of the mine for about six hours, Mikesell later said.

The sheriff confirmed that one person was killed in the incident. Mikesell did not identify the victim but said their death was related to the elevator failure.

"We were able to put together a plan that worked, and that plan was to bring them up through the elevator system," Mikesell said at a news conference Thursday night. "We had other plans that were in place, and luckily, we didn't have to use any of those."

In a statement, Colorado Gov. Jared Polis said state personnel were on site to support local authorities. Mikesell noted that state personnel were able to assist with restoring the elevator system.

"I am saddened to learn of the loss of a life in this tragic accident and my heart goes out to the family and loved ones during this difficult time," Polis said.

Authorities: Unclear what caused the elevator system to malfunction

While authorities were conducting rescue operations, Mikesell said the tour group was in communication with authorities and had supplies, such as drinking water, chairs, and blankets.

"They're all safe at the bottom, with one of the workers here," Mikesell said, but they were not told that someone died, only that there was a problem with the elevator.

Of the 12 people who were trapped, Mikesell said none were injured and that they were able to ascend safely. It's still unclear what caused the elevator system to malfunction, according to Mikesell.

Mikesell said the Occupational Safety and Health Administration and Colorado Division of Reclamation, Mining and Safety are investigating the incident. The incident occurred at the end of mine's tour season, which runs from May through the second weekend in October.

What is the Mollie Kathleen Gold Mine?

The Mollie Kathleen Gold Mine opened in the 1800s and closed in 1961, but continues to conduct tours, according to the mine's website. The mine is located near the town of Cripple Creek, about 45 miles southwest of Colorado Springs.

"Rather than closing down the mine completely, a decision was made to continue tours," the mine's website states. "Tour revenues were used to maintain the mine in safe operable mining condition."

The mine offers one-hour walking tours that allow people to descend 100 stories into the earth, view veins of gold in the mine, and ride an underground tram air locomotive, according to the mine's website.

Mikesell described the mine as a "tourism destination that identifies really what happens in mines," noting that it is a family-owned business that's been operating for "well over 50 years."

The sheriff added that the last time there was an incident at the mine was in the 1980s.

(This story was updated to add new information and correct a misspelling/typo.)

Contributing: Reuters