Rescue crews were working Tuesday to free a man trapped 40 feet inside the Hard Rock Gold Mine above Tabionia, about 100 miles east of Salt Lake City, authorities say.

The mine collapsed at about 10 a.m. on top of an unidentified man. The owner and operator of the mine, Barney Powell of Salt Lake City, notified authorities of the collapse. The victim is believed to be one of Powell's employees.The Duchesne County Sheriff's Department said the cause of the collapse was under investigation.

The mine is located in the Blind Stream area, about 30 yards up Tabby Mountain and is accessible only by trail. Heavy equipment is being brought in to build a road up to the site, authorities said.