As near as I can remember, I read this book in 7th or 8th grade, so figure it would be written toward 10-15 year olds. I'm looking for a book where 2-4 (can't remember exactly) kids decide to explore an old cave/mine system. This isn't a fall-in-the-well rescue story. They get trapped and have to proceed forward to escape, but they were at least partially prepared because I remember them using the terms "belaying" and so on as they explore further. They overcome a number of obstacles and work their way through the cave to ultimately escape.

Any thoughts would be appreciated. My son is fascinated with caving and I thought it might be an interesting read for him.