Some lashed out at the mine co-owner Bob Murray and at the Mine Safety and Health Administration.
"From day one we have been let down by Mr. Murray and by MSHA," testified Michael Marasco, the son-in-law of fallen miner Kerry Allred.
"Mr. Murray told us immediately after the collapse that we could trust God and him and he would stop at nothing to find our loved ones. ... But we were continually let down."
Cesar Sanchez, who sat behind a picture of his deceased brother, Manuel Sanchez, at his wedding, said his family has many questions.
"Someone needed to look after our interests both before the collapse, which would have prevented it, and after the collapse, to assure that everything possible was being done," he said.
The room, packed with witnesses, family members, union officials and workers and mine industry representatives, was heavy with emotions. The family displayed framed pictures of the lost miners on the witness table in front of them.
House Education and Labor Committee Chairman George Miller, D-Calif., commended the family members for speaking out.
"I know your testimony today will be painful for you to deliver," he said in opening remarks. "But it is critical for us to hear from you directly."
Miller also blasted the Labor Department and Murray Energy for failing to produce all the documents the committee had requested. The committee "will not tolerate obstruction or delay" by the department or the company, he said.
Wednesday's committee hearing is the third congressional panel probing the Crandall Canyon mine tragedy, where six miners were trapped and ultimately entombed in the mountain after a pressure-born explosion of coal collapsed part of the tunnel. Three rescue workers were killed and three others injured in another cave-in 10 days later.
Miller's committee has requested thousands of pages of documents and issued the first subpoena in the various investigations, compelling the Labor Department to turn over internal communications.
Utah Gov. Jon Huntsman Jr. will also speak Wednesday, as will Wayne Holland, the head of the Utah Steelworkers Union and the Utah Democratic Party.