What exactly is the media entitled to know?

Here's an interesting story about how several news media organizations has taken the government to court so they can access the government's investigation into the Crandall Canyon (Utah) mine accident. Apparently the Mine Safety and Health Administration (part of the Department of Labor) is not exactly forthcoming about what happened, or what information they've discovered. In this particular case, I think the media organizations are right -- I see no valid reason why this information cannot be made public. Thoughts? Is there ever justification for NOT allowing the media to have all information about a topic or event, e.g., the war in Iraq?