SPECIAL REPORT | FULL COVERAGE

State official: 'We hope for the best'

David Hess, Pennsylvania Department of Environmental Protection

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(CNN) -- As crews worked to free nine miners trapped under more than 200 feet of Pennsylvania rock, CNN's Jeff Flock spoke Thursday with David Hess of the state Department of Environmental Protection.

HESS: Well, right now, we're continuing to pump compressed air into the area of the mine we think the miners are in. We think that bubble is expanding underground, creating a safe haven. And we just moved ... a very sophisticated piece of drilling equipment in to drill a 30-inch hole that we think and we hope will be a rescue channel, a rescue way out of that mine for those miners.

FLOCK: How big an area do you think they're in right now down there? I mean, how much do they have, and what are they in? Are they in water? What have they got?

HESS: It's hard to be very precise, but what we do know is, it's wet. It's dark. And it's a space that's very small, no higher than about 48 or 52 inches. So it's a very confined area.

FLOCK: Again, clarify for us the last time you're sure you heard something from down there because you had tapping overnight. What was the last that you're sure you heard something?

HESS: We regularly tap the casing of the 6-inch well that we put down earlier last night --

FLOCK: That you're putting the compressed air through?

HESS: -- that we're putting the compressed air through, and we tap on it and we heard responses tapping back by someone down there. The last time we heard a clear signal was somewhere around lunchtime. But you have to remember there's a lot of work going on out there, at this point, very noisy, and it's going to get noisier. So we have not, certainly, given up hope.

FLOCK: They may be tapping, and you're just not getting it clearly.

HESS: That's exactly right. ...

FLOCK: And what are you doing about the water? Are you trying to get the water out of there?

HESS: We've had a steady stream of pumps coming in all day to pump water out, to try to not only use the compressed air to expand the bubble, but take out as much water as we can. And we've had offers of pumps from West Virginia, the Corps of Engineers, all over the eastern coal fields. Everybody's wanting to help out in this situation, and we very much appreciate that.

FLOCK: It's way to early to get into this, but I'm going to do it anyway. And that is, the people who are working on this mine clearly knew there was an abandoned mine nearby, correct?

HESS: That's correct.

FLOCK: What happened?

HESS: Well, this mine was abandoned sometime in the 1950s. Pennsylvania generally has a lot of old mines. We've been mining in Pennsylvania for over 100 years.

FLOCK: But you knew about this one.

HESS: That's correct. And we try to keep at least 200 feet of solid rock between an old and a new mine to prevent the kind of problem we have here. But for some reason -- and we're going to investigate this after the rescue effort is over -- for some reason, the old maps were inaccurate, or whatever, for this particular area, and they broke through.

FLOCK: And so you clearly know they broke through --

HESS: Yes.

FLOCK: -- in the new mine, broke into the old mine?

HESS: That's right.

FLOCK: And we just don't know how that --

HESS: We just don't know what -- why that map is wrong, at this point. Like I said ... we're going to put everything into the rescue effort, and then we're going to go back and do an investigation with our federal partners at (Mine Safety and Health Administration) and try to figure out what happened.

FLOCK: And that's my last question, in terms of the rescue effort. What does your gut tell you about this sort of thing? I asked you earlier at the press conference about the history of these sorts of things. It's not particularly good. But what does your gut tell you right now?

HESS: My gut tells me right now that this -- this isn't something, obviously, that happens every day or every year. This is something that is rather unique. And unfortunately, it had to happen here in Somerset County. We've had these problems in the past, but we try to improve our permitting process to avoid these kinds of problems.

FLOCK: But in terms of the survivability of this?

HESS: It's very difficult to say what the chances are. Obviously, we hope for the best, but we also have to be prepared, unfortunately, for the worst. And we want to make sure the families understand that and everybody else understands that. We're just laying all the facts out for everyone to see, at this point.

FLOCK: Yes. David, I appreciate the time.

HESS: Thank you.

FLOCK: Thank you. Thank you so much. I know it's a busy time.