"I think we all understand that underground mining is by its very nature dangerous," Obama told reporters in the White House Rose Garden. "Every miner and every mining family understands this.
"But we know what can cause mine explosions and we know how to prevent them," the president said. "I refuse to accept any number of miner deaths as simply the cost of doing business."
Obama ordered the Labor Department's Mine Safety and Health Administration to immediately examine other mines with "troubling safety records" and to "ensure they aren't facing the same unsafe working conditions that led to this disaster."
The administration also indicated it would work to streamline the process for stepped-up enforcement -- including mine closures -- as well as propose changes to federal mine safety law that would increase criminal penalties and boost MSHA's investigative powers.
Massey responded that the president's statements were "regrettable" and that Obama "has been misinformed about our record and the mining industry in general."
United Mine Workers President Cecil Roberts said Obama's comments were "an unprecedented public stance for an American president to take, and one that is good news for all coal miners in the United States."
Obama spoke 10 days after a massive explosion at the Upper Big Branch Mine killed 29 workers in the worst U.S. coal-mining disaster in 40 years. Labor Secretary Hilda Solis and MSHA chief Joe Main briefed Obama earlier in the Oval Office, proving a preliminary report on the disaster.
Investigators believe the explosion occurred when a buildup of methane gas was somehow ignited, and then probably made far worse by accumulations of coal dust. Upper Big Branch had been cited repeatedly for improper ventilation and for dust accumulations.
"We do know that this tragedy was triggered by a failure at the Upper Big Branch Mine -- a failure first and foremost of management, but also a failure of oversight and a failure of laws so riddled with loopholes that they allow unsafe conditions to continue," Obama said.
In a prepared statement, Massey said the company "believes in safety, accountability and responsibility.
"We seek the truth in the ongoing investigations and are cooperating with federal and state agencies to determine the cause of the tragic accident at Upper Big Branch Mine," Massey said. "Unfortunately, some are rushing to judgment for political gain or to avoid blame. Our goal is to communicate transparently as the facts unfold."