Denver >> Investigators on Friday were trying to figure out what led to an elevator accident inside a former Colorado gold mine that killed a tour guide, injured four others and left 12 people trapped for hours at the bottom of the tourist attraction 1,000 feet beneath the surface.

The elevator was descending into the Mollie Kathleen Gold Mine near the town of Cripple Creek in the mountains near Colorado Springs on Thursday when the door malfunctioned around 500 feet beneath the surface, Teller County Sheriff Jason Mikesell said.

Victim Patrick Weier, 46, was a guide at the mine and a father from the nearby town of Victor, Colorado. The exact circumstances of his death were not disclosed, but the sheriff said he died because of the elevator’s mechanical issue and not due to a medical issue.

Eleven other people, including two children, who were riding the elevator during the mishap were brought up with it following the accident. Four had minor injuries including back pain, neck pain and arm pain, the sheriff said.

Twelve adults from a second group were trapped for about six hours Thursday below ground while engineers made sure the elevator could be used. The group had access to water and used radios to communicate with authorities, who told them there was an elevator issue, Mikesell said.

They were hoisted up in groups of four over 30 minutes. Officials had been prepared to bring them up by rope if necessary.

Most people who were in the elevator when it malfunctioned were later taken to a local relief center where some got showers, new clothes and sandwiches, said Ted Borden, with the Community of Caring Foundation in Cripple Creek.

“It was still very raw, but there was some good camaraderie,” Borden said.

Elevator accidents at mines are extremely rare, said Steven Schafrik, a University of Kentucky associate professor of mining engineering. They have been used by the industry to carry people and material since the mid-1800s, he said, and modern elevators are equipped with fail-safe devices that prevent them from falling far if a cable breaks.

“They’re just ridiculously safe,” Schafrik said of mining elevators. He declined to comment directly on the Colorado accident.Mikesell said the family that owns the mine had operated it for many years and worked to make it safe.

“Anytime you’re dealing with machinery and a 1,000 foot level at the 500 feet level in a mine, there could be accidents,” he said.

Mines that operate as tourist attractions in Colorado must designate someone to inspect the mines and the transportation systems daily, according to the state Division of Reclamation, Mining and Safety. Mikesell said he didn’t know the date of the last inspection at the Mollie Kathleen Mine. Records of the inspections weren’t immediately available online.