Sorry that reality has put a damper on you plans, but that's life.
I'm going to second Mike Lehman's suggestion about scratch building your own mine. Scratch building is a lot of fun, and it is very rewarding, and it is relatively cheap too.
Here is a small mine structure that will sit towards the back of the HOn30 part of my layout:
Obviously this is a very small mine but it suits the space that I have available. Like Mike said, mines are relatively simple structures so they are easy to scratch build. If you want more detailed suggestions, please ask.