A Media Debacle: The Washington Post's Howie Kurtz has it about right, I think:

Sure, the bum information came from West Virginia's governor, and the coal company shamefully refused to correct the record for hours. But the fault lies with the journalists for not instinctively understanding that early, fragmentary information in times of crisis is often wrong. You don't broadcast or publish
until it's absolutely nailed down, or at least you hedge the report six ways to Sunday. This was, quite simply, a media debacle, born of news organizations' feverish need to breathlessly report each development 30 seconds ahead of their competitors.

Most of the erroneous stories (including the Post's) cited no source for their claims that the miners were alive. A semi-honorable semi-exception was The New York Times, with its "12 Miners Are Found Alive, Family Members Say" headline.