In my own brain I wonder if it didn't happen something like this: They found the miner who is alive and got him out. Mean while, they were checking the others for signs of life. Mean while, someone called and said they found one alive and were checking for vitals on the others and who ever got the call just assumed the others were alive too?
By the way, why did they have to wait hours to go get the bodies of the others but were able to get the one out then?

There are reports today, that they found letters to loved ones by the bodies. Such a sad sad thing!