Fires like this are apparently next to impossible to put out, and they create hazards like carbon monoxide and sinkholes, so in the last few decades the town has been all but abandoned. The pictures are interesting (links to more of them at the bottom of the article).
I first heard of this from anukul and danitapgh, who I believe drove through or near the town on a trip once. Recently I mentioned it to someone and they found the idea of an underground fire burning for so long hard to believe, so I said I'd send them a reference. Unfortunately, I can't remember who that was now, so I'll post it to Livejournal instead.