Hah! Similarly surprised to see this here. I spent a little bit of time with John back in the summer of 2007 during a research project at the University of Minnesota. I had just finished my full cave diving certification and got roped into an attempt to push past a sump at the end of Coldwater Cave in northern Iowa. It was unfortunately unsuccessful; after a few dozen feet underwater the passage cinched down to just a few inches wide. Oh well.

The article captures well the cold war between Ackerman and the Minnesota DNR; I was warned not to mention John's name when helping survey part of the DNR's Mystery Cave, and the article says John still hasn't managed to get access to the cave's unsurveyed areas, 13 years later.

Then again, when the DNR blocks you from a cave's public entrance and you respond by hiring a well-borer to drill a private entrance across the road... well, it's not the most friendly of relationships. Photos of that whole process at http://www.cavepreserve.com/goliath.html. If I recall correctly, John took a some pleasure from the fact that the DNR can't access the full extent of Goliath's Cave under their property without first trespassing into passages that he owns. And indeed, the property line is prominently marked on the map linked from that page!