I like these examples a lot!
After reading an article I found through abhilash2863's blog, I had a go at it myself. I tried to stick to the method as it was being described as closely as possible.
Also I couldn't resist and used the newly released Data Structures plugin to create the "miners", which seemed like a weird idea at first but worked out surprisingly well:
<img src="http://dl.dropbox.com/u/2306601/cavetest.png">
I didn't manage to get the cave completely cleaned up yet as you can see, although most of the cluttery parts have been eliminated.
I want to have another try at it, probably solely using the S plugin. Once I'm satisfied I will also post the cap.