A zinc-silver mine in the Yukon Territories collapsed early Sunday morning, killing a worker performing a maintenance check inside.

Mounties say the collapse occurred at about 3:30 a.m. in a mine shaft of the Wolverine Project, located about 600 kilometres northeast of Whitehorse.

RCMP "M" Division spokesman Sgt. Don Rogers said three men were deep within the mine doing a routine equipment check at the time.

"Suddenly the mine, the roof, the wall, whatever it was gave way and two of the workers were hit by debris and knocked backwards," he said.

"A third worker was unfortunately trapped."

When emergency crews reached the trapped miner at 3 p.m. he had already died, Rogers said.

Of the two other workers, one was taken to hospital with bruises and released. Details of the other's injuries are unknown.

The cause of the collapse has not been determined, but several agencies remain at the scene conducting investigations.

"Workers compensation is out there, as well as representatives from the coroner's office and we've got members of the RCMP Major Crime Unit," Rogers said. "We want to ensure that we complete a thorough investigation,"

Vancouver resident Mike Redfearn, a miner for 40 years, says his grandson is an employee at the mine. He learned about the collapse when he arrived for work Sunday morning.

He was able to contact family in Metro Vancouver shortly after, but has not been heard from since.

"He's at the site and apparently they can't call out, there's very few phone lines and they're totally tied up," Redfearn said.

The mine has a good reputation in the industry, he added.

"I have not heard anything negative come out about this project," he said.