Water from that mine flooded the shaft where the miners were working Wednesday, trapping the men 240 feet underground. They were pulled safely from the mine about 55 miles southeast of Pittsburgh early Sunday.
Thomas Foy, 51, was the only miner still hospitalized Tuesday. Foy, who was in good condition, has a history of heart problems, but hospital spokeswoman Dianne DeLisa declined to say why he was being kept in the hospital other than to say tests were being conducted.
The miners trusted a map that showed a dangerous water-filled mine more than 300 feet away. The problem was that the survey was off. They weren't digging 300 feet away; it was more like three feet away.
"It didn't show it on the map, and nobody knew it was there," said John Unger, one of the rescued miners. Like the rest of his waterlogged crew, he assumed the shaft they were digging in was safe, reports CBS News Correspondent Lee Cowan.
Sending test probes into the rock could have helped, but because the maps showed the water-filled mine so far away, state law didn't require those probes to be drilled.
"We were not required under statutes today to advance drill because (we believed) we were not close enough to do that," said Dave Rebuck, president of Black Wolf Coal Co. "What I know is we should have been far enough away from that mine."
State mine officials have described underground maps as notoriously sketchy, and are now reviewing operations at 34 other Pennsylvania mines that are located next to abandoned mines to determine whether changes are warranted.
Gov. Mark Schweiker said Monday that a special state commission will examine mine safety and recommend changes to prevent accidents like the one that trapped nine men in a flooded coal mine for more than three days.
"Our first step is to understand exactly what happened," Schweiker said.
Richard Stickler, director of the state Bureau of Deep Mine Safety, said maps will be a key focus of a joint state-federal investigation.
"You rely on those maps as being accurate and safe," said Dave Lauriski, assistant secretary for the U.S. Mine Safety and Health Administration.
On Tuesday, water was still being pumped out of the mine — about 40 feet of which had been removed. Rebuck said the investigation team made up of the federal Mine Safety and Health Administration, the state Department of Environmental Protection and Black Wolf Coal officials likely would not be able to get to the accident site for several weeks.
Workers will focus on pumping water out, repairing equipment damaged by the flooding and fixing the air ventilation system, Rebuck said. The site where miners tapped into the old Saxman Mine, causing the flooding, could be sealed or water could be pumped out of both mines, he said.
Rebuck said he hopes the accident will lead to mining safety reform.
"I believe something will change," he said.
Rebuck credited high-tech surveying technology for locating the miners.
"We know our surveying has been very good, the fact the escape holes hit right on top of them," Rebuck said.
He vowed to resume operations at the coal mine at all cost and estimated that it could take months to reopen.
The mine has been cited for safety violations in the past but Rebuck said they were for minor offenses such as not having a functioning fire extinguisher and cracks in cement walls caused by aboveground pressure.
There is no estimate on the cost of damages, but Rebuck said the cost of cleaning up the dairy farm and the mine will likely be shared between Black Wolf, PBS Coals and insurers.
Rebuck said he did not have time to speak with the miners in the hours after their rescue but had met with eight and spoken to a ninth by phone by the end of the day Monday.
He said the men would be paid for the time they were in the mine, though he declined to specify the amount, and would receive medical and workers compensation benefits.
"They wanted pay for the time they were in the mine. That's reasonable to me, so we worked out an agreement," he said.