Denver >> Investigators were trying to figure out Friday what led to an elevator door malfunction at a former Colorado gold mine that killed a man, 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 tour 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 it was because of the elevator’s mechanical problem and not due to a medical issue.

Eleven other people, including two children, who were riding the elevator were rescued. 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. They had access to water and used radios to communicate with authorities, who told them there was an elevator issue, Mikesell 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 there’s a cable break.

“Stupid 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.