Rescuers prepare to enter W. Virginia mine

Rescuers were getting ready Wednesday night to enter a West Virginia mine to try to locate four workers believed trapped by explosion earlier this week, as reports surfaced that the mine had been cited for safety violations on the day of the blast.

An explosion Monday at the Upper Big Branch Mine-South in Raleigh County, about 50 kilometres south of Charleston, killed 25 miners. Four are still unaccounted for.

The level of methane gas has been too high and dangerous to send rescuers into the mine, but Kevin Stricklin of the U.S. Mine Safety and Health Administration said it's possible crews could enter the mine as soon as Wednesday night.

"We're getting a little closer to rescue teams going underground. We've basically asked the rescue teams to come to the mine site, and they're ready and prepared to go underground as needed," Stricklin said.

Rescue teams have drilled five holes into the mine to vent the gases. So far, there has been no response from banging on a drill pipe for about 15 minutes after the first hole was drilled.

Once rescuers can get into the mine, it should take less than two hours for a team to get far enough inside to check for survivors, depending on conditions, Stricklin predicted.

The miners are thought to be trapped about 335 metres below ground. Three of them are presumed to be in or near a safety shelter stocked with enough food and water for four days, while the fourth is likely 300 metres away.

"We've asked the families to be patient," Stricklin said, adding that family members of the miners supported the decision to hold off on sending rescue crews.

Meanwhile, reports surfaced that the Massey Energy coal mine was cited for violating for two federal safety violations on the day of the blast. One of the violations involved inadequate maps of escape routes from the Upper Big Branch mine.

The other involved an improper splice of electrical cable on a piece of equipment.

Safety to be reviewed

The mine, which has a long history of safety violations, is operated by Performance Coal Co., a subsidiary of Massey Energy Co.

The company's chief executive said the mine was not unsafe, but federal regulators planned to review the violations, many of which involved venting methane gas. If the odourless, colourless gas is not kept at safe levels, a small spark can ignite it.

Massey Energy Co. was fined more than $382,000 in the past year for repeated serious violations involving its ventilation plan and equipment.

The death toll in Monday's explosion was the highest in a U.S. mine since 1984, when 27 people died in a fire at Emery Mining Corp.'s mine in Orangeville, Utah. If the four missing bring the total to 29, it would be the most to die in a U.S. coal mine since a 1970 explosion killed 38 at Finley Coal Co. in Hyden, Ky.