I think you are correct Johndefur. Ring of Fire is a commonly used geologic term. It basically signifies the ring formed by volcanic action. But when you have volcanic activity, that's how minerals are formed. I also agree he means the Sachigi Greenstone belt.

 Here is a link on Wikpedia,,,,Pacific Ring of Fire. It's written in easy to understand terms. The Pacific Ring of Fire is responsible for some of the largest mineral resources in the world.

http://en.wikipedia.org/wiki/Pacific_Ring_of_Fire