CNN
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One person has died and 23 people have been rescued after being trapped for several hundred meters underground at the Mollie Kathleen Gold Mine, a tourist mine in Cripple Creek, Colorado, officials said Thursday.

Eleven people were rescued early Thursday and a dozen more people arrived from abroad were trapped at the bottom of the 1,000-foot-deep mine for about six hours before being rescued Thursday evening.

“I am relieved that 12 of the people trapped in the Mollie Kathleen Mine have been safely rescued. Our deepest condolences go out to the family and friends of the person who died in this incident,” Colorado Gov. Jared Polis said in a statement Thursday evening.

Among those rescued were two children and four were being evaluated by medical personnel for minor injuries, according to Teller County Sheriff Jason Mikesell, who did not provide details about the deaths.

Around noon Thursday, the mine experienced a mechanical problem with the elevator system that “posed a serious danger to participants,” Mikesell said during a news conference. The cause of the accident is still being investigated.

Because the 12 people were stuck in frigid temperatures of around 10 degrees Celsius, they had water, blankets, chairs and a radio, Mikesell said. However, according to the tour website, there were no facilities such as toilets underground.

“We are thrilled to hear that all 12 people still at the Mollie Kathleen Gold Mine were safely rescued,” the Colorado Springs Fire Department said said in a social media post Thursday evening. “We are grateful for the work of all first responders who ensured the safety of those still inside. Our condolences go out to the family who lost a loved one this evening. Please pray for them.”

According to Mikesell, the deceased person’s body was recovered when the first group was taken up in an elevator after getting stuck halfway up at a depth of 500 feet.

To save the last group, inspectors made sure the elevator was working properly to take them up four at a time, Mikesell said.

“We had a meeting with them to explain to them what was going on because they were in that tunnel and didn’t know any of this was going on,” Mikesell said.

The mine – a family-owned tourist attraction for “well over 50 years” – last experienced an accident in 1986, Mikesell said. This accident left two people trapped in an elevator, but no fatalities were reported.

The hour-long tour — a completely underground experience that takes guests through the 1890s gold mine — “is not claustrophobic, but the descent into the shaft is very close for 2 minutes (in each direction),” the tour says website.

After descending the elevator at a speed of approximately 5 mph, guests take a short ride on a subway car and then continue on foot for a quarter-mile flat and level walk. They will be shown how gold mining worked, according to the website. Guests will be provided with safety helmets and asked to leave personal items such as walkers and wheelchairs behind during the tour.

The attraction was scheduled to close for the season this weekend before reopening in May.