EUREKA, Nev. (AP) — The death of an employee at a northern Nevada gold mine site was from apparent medical causes and wasn’t directly work-related, a sheriff said Friday.

Thomas Avery, 60, of Spring Creek, Nevada, died Thursday at the Carlin Operation, North Area mine despite attempts by co-workers and company emergency medics to revive him after he became unconscious, Eureka County Sheriff Jesse Watts said.

The sheriff corrected his earlier description of the death as “mining-related,” saying that while Avery died on mine property his death “appears to be from a medical event.”

The exact cause and manner of Avery’s death will be determined following an autopsy, Watts said.

The sheriff said earlier the U.S. Mine Safety & Health Administration was notified because the death occurred at the sprawling Goldstrike mine site about 25 miles (40 kilometers) northwest of Carlin.

Goldstrike is one of several mines operated by Nevada Gold Mines, a joint venture between Barrick Gold Corp. and Newmont Goldcorp Corp. The complex includes an open pit visible from space and underground mines.