SAN JUAN DE SABINAS, Mexico -- Teams of experts drilled holes above a collapsed coal mine Saturday to release toxic gases that have forced rescuers to suspend a search for 65 miners trapped by an explosion a week ago.
Machines bored holes up to 10 inches in diameter up to 560 feet deep, to the bottom of the Pasta de Conchos mine, and officials were analyzing the air quality. On Friday, officials suspended the search for three days, saying the level of poisonous gases could threaten the rescue teams.
Juan Rebolledo, vice president of international affairs for Grupo Mexico SA de CV, which owns the mine, said officials planned to drill up to four holes, depending on the gas levels detected.
"We are looking to get to where the miners are thought to be," Rebolledo said.
The government and the Grupo Mexico unit that manages the mine, Industrial Minera Mexico, have said it is highly unlikely any of the missing miners are still alive.
They were carrying only a small supply of oxygen and presumably have not eaten or had water since a pre-dawn explosion caused by rising gas levels inside the mine on Feb. 19 brought down thousands of tons of rubble.
Grupo Mexico insisted that it wasn't giving up on the missing miners.
"The suspension is temporary and in principle will be for three days," the company said in a statement. "It does not mean that rescue efforts are suspended indefinitely. Those efforts will continue when necessary conditions are met."
President Vicente Fox also said the search wouldn't be permanently suspended.
"Work has not stopped," Fox told reporters. "They are making direct perforations so as to arrive to points where they believe the miners to be trapped."
For more than five days, rescuers -- many of whom were miners -- have dug with picks, shovels, and their hands to avoid explosions that could be sparked by machinery.
Mine operators say the blast was an accident and that Pasta de Conchos had passed recent government inspections.
Rescuers had advanced 900 yards inside the 1.75-mile-long mine, to an area where as many as 26 miners were believed to be trapped. But mine officials said there is no sign of them, meaning they either had been buried under debris or were in a different part of the mine.
Mexican scientists and the U.S. experts have already concluded that because of high levels of toxic gas, no one working in that section could have survived.