Crews were tapping the drill steel to see if anyone would respond to noise and also testing the air for oxygen content, said Rich Kulczewski, a spokesman for the federal Mine Safety and Health Administration.

He had no results. It was not immediately known when the camera would be lowered through the hole, which is nearly 9 inches in diameter and 1,856 feet long.

Meanwhile, MSHA said the man who led the government's investigation of the Sago mine tragedy in West Virginia will direct a similar probe of the Utah mine disaster.

Richard Gates, an MSHA district manager in Alabama, has been with the agency for 19 years.

"MSHA's investigation will fully examine all available evidence to find the cause of the ground failure at Crandall Canyon mine and any violations of safety and health standards," MSHA chief Richard Stickler said in a statement.

Six miners have been trapped more than 1,500 feet below ground since Aug. 6. It is not known if they are dead or alive. Three rescuers trying to tunnel to the men died during another collapse Aug. 16.

Stickler said the investigation at Crandall Canyon would involve people who have no ties to MSHA's Western district, which oversees safety at the mine, 120 miles south of Salt Lake City.

They include Timothy Watkins, assistant district manager in Kentucky who has ventilation and retreat mining experience; Gary Smith, a supervisor in Pennsylvania who has roof-control expertise; and Joseph O'Donnell who is based in MSHA's district office in Alabama.

In January 2006, 12 people were killed in an explosion at the Sago mine in West Virginia.

University of Utah seismologists insist the Crandall Canyon cave-in was violent enough to cause a 3.9 magnitude earthquake. The mine's co-owner, Murray Energy Corp., claims a natural earthquake caused the disaster.