An October elevator malfunction in a Colorado gold mine that killed a tour guide and stranded nearly two dozen people underground for hours was caused by “operator error,” Teller County sheriff’s officials said Wednesday.

Investigators determined that the incident at the Colorado tourist mine was "not attributed to current mine practices or equipment malfunctions."

Authorities say an incident involving an elevator at a former Colorado gold mine that led to the death of a tour guide and trapped a group of tourists for hours last year was caused by “operator error.