A team of federal investigators will arrive Monday as officials try to figure out what caused the blast. Virginia-based Massey has been under scrutiny for a string of safety violations at the mine, though CEO Don Blankenship has defended the company’s record.

A pair of tall black boots and a lunch pail sat near the altar Sunday at the New Life Assembly church in Pettus, West Virginia – a memorial to the 29 men killed in the worst U.S. mining disaster since 1970 and a thank-you to those who make their living inside the mountains.

This day, the first Sunday since last Monday’s explosion killed 28 workers and a contractor at Massey Energy Co.’s Upper Big Branch mine in Montcoal, was for many a time to honor the profession. Tears of mourning fell, and arms swayed in worship among the 50 people gathered at the church.

Pastor Gary Williams, who has worked at Massey Energy mines for 18 years, knew many of the victims. On his way to church Sunday morning, he heard Ricky Workman’s name among them for the first time.

“I know his child. I know his wife. He’s a part of my family. He’s a part of my life,” Williams said, tears falling. “Over time, our hearts and the emptiness that we have inside will fade away, but I don’t never want to forget what happened April 5, 2010.”

Some of those who died have already been laid to rest. Crews worked Sunday to remove the bodies of several others who didn’t make it out, but the recovery had to be halted because of high gas readings in the mine. Crews need to drill another hole to vent the mine before they can continue.