Crews began the arduous process of removing layers of rubble and debris in the search for a missing worker Thursday at a collapsed coal mine preparation plant in eastern Kentucky where a second worker died.

The 11-story abandoned building crashed down Tuesday night at the Martin Mine Prep Plant in Martin County while it was undergoing work toward its demolition. Officials briefly made contact with one of the two men working inside, but announced Wednesday he died amid rescue efforts. Authorities said Thursday they have not had any communication with the second worker since the building collapsed at around 6:30 p.m. Tuesday in Inez, a town of about 500 people.

“We haven’t given up hope,” Martin County Judge Executive Lon Lafferty said at a news conference with reporters Thursday.

Lafferty said a family member of the deceased man was at the site before he died and was able to speak with him. Crews have located his remains, but have not yet been able to remove them.

Lafferty said the process has taken a mental and physical toll on rescue workers, calling them “the most mentally strong and emotionally strong people, the bravest people” he’s ever known.

“To go underneath a structure like that and risk your own life to try to secure someone else’s life I think is one of the greatest attributes of the human spirit,” he said, adding: “You can’t be involved in something like this and not have emotions about it.”

Crews have delved under layers of steel and concrete with search dogs and listening devices, he said. In the second full day of rescue efforts, officials are removing the debris into smaller piles for the search.

Heavy equipment is being hauled to Inez from across Kentucky and out-of-state to help with the efforts. Louisville Metro Emergency Services Director Jody Meiman said some began arriving on the site Wednesday night. Search groups have been assigned to comb through rubble as it is removed.

“It’s a very methodical process, it’s a very slow process, but it’s a process that has to take place in order to get down into the building in where that last known location was,” he said.

He said responders were being rotated in shifts. Meiman said the building moved several times Wednesday.

“It is dangerous. It continues to be dangerous,” he said.

Director of Kentucky Emergency Management Col. Jeremy Slinker said rescuers worked throughout Wednesday night without breaks. Slinker estimated that up to 50 rescue workers and 25 support personnel at a time were involved in the search.

“We’re planning it out for a long operation and what we hope is we have some happy success really quick,” he said.

Several state agencies have begun investigations into the collapse and possible causes, including Kentucky state police.

The Kentucky Division of Occupational Safety and Health Compliance said one of its officers was on site and that an inspection had been opened with Lexington Coal Company LLC, which had contracted with Skeens Enterprises LLC for site demolition and salvage operations.

The division said the investigation could take up to six months to complete.

President Lyndon Johnson visited Inez during his “War On Poverty” in 1964.

In 2000, a coal-sludge impoundment in Inez collapsed, sending an estimated 300 million gallons into the Big Sandy River and its tributaries. A byproduct of purifying coal, the sludge oozed into yards and streams for miles in what was considered one of the South’s worst environmental disasters at the time.