Very fun topic to think about. My $.02: Together with the genetic diversity you need food, lots of food. I bet if you look up the average hunter-gatherer village size, that's about the maximum size of a population you can support on just hunter-gathering and perhaps some basic farming.

To get a civilization that could support even a modest town large enough to support small mining operations and general trade you need the most important technology we've spent the past 10.000-40.000 years developing and which I don't see any technological shortcut to: The potato, banana, the chicken, the cow, etc. Superfoods, without which a civilization won't get very far and which will definitely not just exist on a planet that's never seen human cultivation.

(There's a fun survivorman episode where he gets dropped in a jungle, and after a day or two of hardship he stumbles upon an abandoned farm, instantly the whole 'surviving' aspect is gone and the rest of the episode is about him trying to live comfortably (i.e. not being eaten by ants at night), the difference between a bleeding edge modern mango and sucking on a wild berry is stark (the episode is called "Grenada Jungle"))

One of my supervisor's colleagues wrote a book on bootstrapping which I've been meaning to read: http://www.amazon.co.uk/The-Knowledge-Rebuild-World-Scratch/...

He also gave a Google talk a while back https://www.youtube.com/watch?v=EdRV8ccyEE0