Two fundamental arguments of the thesis that we will not "run out" of natural resources for productive purpose have been made eloquently in:

- The Ultimate Resource by Julian Simon [1] --the human mind has limitless potential to select and pursue the use of materials; and

- Capitalism by George Reisman [2] -- the phenomenon of price responds to actual supply and demand, and prompts profit-seekers to develop and switch production accordingly.

[1] http://www.amazon.com/dp/0691003815

[2] http://www.amazon.com/dp/B0084RU67S, see Part One, Chapter 3

[1] is the book I had in mind.

I think it's pointless to argue about it in that way, though. If you can think of a supposed example (or more than one) of a monopoly that doesn't derive from government power, I'll either explain to you why that's not the case, or concede the point. I scanned at the list of examples on Wikipedia briefly, and didn't find any "free market monopolies."

[1] http://www.amazon.com/Capitalism-Treatise-Economics-George-R...