The families of each of the victims were given a miner's helmet which they placed on the 29 white crosses that lined the stage.
Relatives, government officials, rescuers and the president all attended Sunday's memorial for the men who died in the April 5 explosion and fire at the upper big branch mine
"Nothing I say can fill the hole they leave in your hearts; the absence they leave in your lives," President Obama said. "We have to lean on one another and look out for one another and love one another and pray for one another"
Investigators still have not determined what caused the deadly explosion.