By Laura Zuckerman
SALMON, Idaho (Reuters) - Rescuers on Saturday had yet to make contact with a miner trapped more than a mile below ground after a silver mine in Idaho collapsed for unknown reasons Friday evening, officials said.
The miner was one of two workers tapping a vein of silver in a mine owned by Hecla Mining Company in northern Idaho when a section of tunnel caved in, according to the company.
One miner was uninjured but the collapse trapped his co-worker, whose condition is unknown. Rescuers have been unable to make contact with the man, who has been cut off for nearly 24 hours.
"This is an extremely difficult situation; we are very concerned for this miner," Hecla spokesman Mike Dexter told Reuters in a telephone interview.
He said any comment on the challenges facing the miner would be pure speculation.
"The roof fell in; you can imagine his predicament," Dexter said.
By early evening on Saturday, a team skilled in mine rescue had cleared 25 feet of an estimated 75-foot blockage in a corridor of the Lucky Friday Mine and was securing the ground as it advanced.
Officials said all attention and resources were concentrated on the miner, with three 10-person crews working in shifts around the clock, rather than investigating the cause of the collapse.
"The company is not yet focused on why and how this occurred; our current focus is 100 percent directed to rescuing the miner and ensuring the safety of the rescue team," Melanie Hennessey, Hecla's vice president for investor relations, said in a statement.
The company is offering professional support and emotional counseling to the miner's family and co-workers, she said.
The accident comes as Hecla is seeking to expand the depth of the Lucky Friday to 8,000 feet.
It happened the same day the U.S. Department of Labor released a report faulting federal mining inspectors who oversee safety for failing in some instances in 2010 to "properly evaluate the gravity and negligence in certain citations."
Hecla employs 275 workers and 100 contractors at the Lucky Friday, a hard-rock mining operation located in an historic silver mining district east of Coeur d'Alene, Idaho, near the Idaho-Montana border.
The operation uses a mining method known as cut-and-fill, where cuts into silver-bearing ore are backfilled with waste rock before a new section of the vein is tapped.
The ore is hauled one mile to the surface, where it is milled into a concentrate shipped to British Columbia for smelting into silver, lead and zinc.
The mine, which has been in production for nearly 70 years, yielded 3.5 million ounces of silver in 2009. It also produces lead and zinc.
The Lucky Friday is one of three active mines in the United States owned by Hecla, which is based in Coeur d'Alene.
(Editing by Dan Whitcomb)