Greetings all!
I've been exploring caves and mines for about 3 years now, mostly across north-central Illinois, but also in Minnesota, Iowa, Wisconsin, and Indiana. It's seems like I'm beginning to run out of leads that I can pull from old publicly accessible mine surveys around here, which has led me to turn my interest a bit more towards natural caves. Still have a few more promising holes on the checklist to get to, but after that I am thinking I will likely join NSS and get in contact with the Windy City Grotto.
Quite a wealth of information and healthy discussion you've got going on here. I'm hoping to learn a lot and meet a few of you in the future.
--Stormy