HUNTINGTON, Utah — Hundreds of rescuers broke through walls of rock yesterday in a desperate race to reach six coal miners trapped 1,500 feet below ground by a cave-in so powerful authorities initially thought it was an earthquake. Hours after the collapse, which did not appear related to an explosion, searchers had been unable to contact the miners and could not say whether they were dead or alive. If they survived, a mine executive said, they could have enough air and water to last several days.

“We’re going to get them,” said Robert Murray, chairman of Murray Energy Corp. of Cleveland, a part owner of the Crandall Canyon mine. “There is nothing on my mind right now except getting those miners out.”

The mining crew was believed to be about four miles from the mine entrance. Rescuers were working to free the men by drilling into the mine vertically from the mountaintop and horizontally from the side, Mr. Murray said. Officials estimated that drilling vertically could take three days. If they are able to open an old mine shaft, Mr. Murray said, rescuers believe they can get within 100 feet of where the men are trapped.

“The idea is to get a hole into where they are,” Mr. Murray said. “They could be in a chamber 1,000 feet long, or they could be dead. We just don’t know right now.”