President Obama, delivering a eulogy Sunday for the 29 workers who died in a West Virginia coal mine explosion, said their deaths should serve as a call to action to improve mine safety and prevent a similar tragedy from ever happening again. 

Obama and Vice President Biden met privately with the families who lost loved ones before closing the memorial service with their remarks. 

The president said in his eulogy that letters have poured into the White House since the April 5 disaster at the Upper Big Branch mine. "They make a simple plea: don't let this happen again," Obama said. 

The president questioned how a country that relies on miners could "fail" in its duty to protect them, but said that must change. 

"We cannot bring back the 29 men we lost. They are with the Lord now. Our task, here on Earth, is to save lives from being lost in another such tragedy. To do what must be done, individually and collectively, to assure safe conditions underground," Obama said at the service in Beckley, W.Va. "To treat our miners the way they treat each other -- like family. For we are all family. We are Americans." 

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The eulogy focused heavily on the contributions of the miners who died. Obama said the miners "knew there were risks," but weren't doing the job for themselves. 

"All the hard work. All the hardship. All the time spent underground. It was all for their families. For a car in the driveway. For a roof overhead," he said. "These miners lived -- as they died -- in pursuit of the American dream." 

Obama urged Americans to remember the hardship miners endure to keep the country running. 

"Day after day, they would burrow into the coal, the fruits of their labor, what we so often take for granted -- the electricity that lights up convention centers like this, that lights up our churches and homes, our schools and offices, the energy that powers our country and the world," Obama said. "Most days, they would emerge from the dark mine, squinting at the light. Most days, they would emerge, sweaty, dirty, dusted with coal. Most days, they would come home. Most days, but not that day."