Maybe I read about it in a collection of art by Paul Lafolley.
I forgot where I initially encountered Mel's hole (though it wasn't through Art Bell or his radio show, which I have never heard), but I have been fascinated by the whole hole phenomenon, and not simply the impossible hole itself, ever since.
This catalog from a most unlikely exhibition comprises essays, artworks—many quite good— and a short story, all inspired by this "paranormal land event occurring in radiospace." Meanwhile here is a Washington geologist, debunking the tale-spinner calling himself Mel Waters and showing off a mundane hole that was possibly the basis for Mel's hole. I liked the responses of the artists and writers herein better. Just saying.