Family members of the missing miners said Thursday that they want drilling to continue even if the sixth hole fails to show signs of life. The family members did not want to be identified.

Huntington, Utah ? Even as crews began a last effort Thursday to find six trapped miners, lawmakers in Washington launched separate reviews of whether the mining that preceded the thunderous cave-in was too aggressive.

As a drill bored a sixth hole into the side of a mountain, Sen. Edward Kennedy, chairman of the Health, Education, Labor and Pensions Committee, demanded a litany of documents from the Labor Department about the Crandall Canyon Mine and its operators.

“The loss of life at the mine, and the devastating emotional toll on families of the victims, underscore the urgent need for a thorough examination of our federal system of mine safety,” Kennedy, D-Mass., wrote to Labor Secretary Elaine Chao.

The six miners have been trapped since Aug. 6, and searchers have found no sign they survived. Three other miners were killed and six more injured last week when the shifting mountain crumbled around them as they tunneled toward the missing men. Tunneling has not resumed.

Kennedy wants to review several petitions the mine’s co-owner, Bob Murray, made to the Mine Safety and Health Administration for changes in his mining plans at Crandall Canyon, among other documents. Experts have said the proposed changes were risky and could have led to the initial collapse.

The Senate Appropriations subcommittee that oversees labor issues announced plans for a hearing on the mine collapse when Congress returns from its summer break Sept. 5. The subcommittee wants to question Murray and MSHA chief Richard Stickler.

Officials with Murray’s company did not return repeated requests for comment Thursday.

At the mine, crews began working on the sixth test hole to try to locate the men.

The federal Mine Safety and Health Administration said in a news release Thursday that no air samples or video images could be obtained from the fifth hole because it became plugged with mud.

Other holes provided only grainy video images of rubble and poor air sample readings, and efforts to signal the miners have met with silence.

The sixth hole will head toward an area where the miners were last believed to have been working, some 1,500 feet below the surface. It was expected to be completed over the weekend.

“This is the last hole,” Murray said Wednesday night. Drilling it, he said, will “bring closure to me that I could never get them out alive.”

Sonny Olsen, an attorney acting as spokesman for the families, said Thursday night that the families want drilling to continue even if the sixth hole fails to show signs of life. If rescue is not possible, the families want the men’s bodies to be retrieved.

“Sealing up the mine with our loved ones inside without knowing if they’ve perished is outrageous to us,” said Olsen, reading from a statement. “There’s been no indication that these men are not alive. The families acknowledge that there’s an issue with the air. These men are trained on how to survive in these kinds of environments.”