The individuals were part of a tour group visiting the Mollie Kathleen Gold Mine on Thursday.

One person has died, and nearly two dozen others were rescued Thursday after becoming trapped underground due to an equipment failure at a gold mine in Colorado, according to officials.

The individuals were part of a tour group that got stuck near the bottom of the Mollie Kathleen Gold Mine in Cripple Creek around noon MDT on Thursday. Teller County Sheriff Jason Mikesell confirmed that one person died during the incident, while 23 others were trapped in the mine shaft.

“I am relieved that 12 of the people trapped in the Mollie Kathleen Mine have been safely rescued,” Colorado Governor Jared Polis stated Thursday night. “Our deepest condolences to the family and friends of the individual lost in this incident,” he added.

Earlier in the day, eleven individuals were rescued, including two children. Rescuers brought the trapped adults up four at a time to ensure the safe extraction of the remaining twelve, as Sheriff Mikesell explained during a press conference following the rescue operation.

The death was related to the elevator malfunction, although further details were not disclosed by Mikesell.

To initiate the rescue, engineers first repaired the elevator, which had been stuck at a depth of 500 feet. They inspected the cables and conducted a test run, sending the elevator down to the 1,000-foot level and bringing it back up. Once that was successful, the rescue operation began.

UCHealth, the local hospital, reported receiving seven patients from the incident, all of whom were treated and released.

Elevator and mine safety experts were on-site to assess the safety of the elevator before it was used to lift those trapped back to the surface. Sheriff Mikesell mentioned that there were three plans in total for the rescue operation, with repairing the elevator being the primary plan.

The Occupational Safety and Health Administration (OSHA) and Mine Safety officials will investigate the incident.

Sheriff Mikesell noted that there was no concern about oxygen levels running low for those trapped, as they had access to water, chairs, and blankets, and were able to communicate with rescuers throughout the ordeal.

The Mollie Kathleen Gold Mine, which reaches a depth of about 1,000 feet, is a well-known tourist attraction. Sheriff Mikesell remarked that there hadn’t been an incident of this nature since 1986.

Multiple agencies, including search and rescue teams, responded to the incident with heavy equipment.

In a statement issued Thursday afternoon, Governor Polis announced that he was monitoring the situation and deploying state resources to assist in the rescue efforts. “I have spoken to the Teller County Sheriff and County Commissioners and will stay in touch throughout the course of this rescue effort,” Polis said at the time. “The state is assisting Teller County and sending resources to rescue those inside the mine. We will do everything possible to assist the county in ensuring a speedy and safe resolution to this situation,” he added.