A camera lowered into a collapsed coal mine revealed equipment but not the six missing miners, and officials planned to drill yet another hole in a desperate hope of finding signs of life nearly a week after a thunderous cave-in.
Poor lighting allowed the camera to only see about 4.5m into a space where they hoped to find the men. The video showed only a tool bag, a chain and other equipment, said Richard Stickler, head of the Mine Safety and Health Administration.
"We did not see any sign at all of any of the miners," Stickler said on Sunday.
He said officials would try again with an improved lighting system, which should allow the camera to see 30m. It was not clear when the attempt would be made.
The view of the equipment was recorded overnight on the camera's second attempt to find signs of the miners. On its first descent on Saturday, during which one lens was impaired, the camera showed a 1.7m-high void described by Stickler as "survivable space."
The men have not been heard from since the mine was struck by an earthshaking collapse early last Monday. Rescue leaders said they were proceeding as if the miners were alive.
"Our attitude is we always have to have hope, and our position is that we're hoping and we're praying and it would be a terrible mistake to give up hope until you know for sure," Stickler said.
The drill rig was to be relocated to a new position late on Sunday to create a new hole 431m deep. The previous holes were more than 550m.
Bob Murray, head of Murray Energy Corp, co-owner of the mine, said the new hole would target an area that the miners would have gone if air in their original location was bad.
Stickler would not estimate how long it would take to drill the new hole.
Murray initially estimated three to four days, but his vice president, Rob Moore, said quietly to him during a news conference that it could be up to six days.