Here is the ingame loop, it is more like 2 minutes long then one minute like you mentioned, but (correct me if I'm wrong) it doesn't really matter right? will be producing the menu loop shortly.

Hope this has the feel you desired, contact me if you have any suggestions or questions

P.S. - If the beginning sounds really strange, that is to replicate the desired endless loop effect. If you will note, the end of the loop has a massive build and would have a major echo. That echo is at the beginning of the loop (which mean you will most likely want to fade the loop in at the beginning.