The other reason I believe that the mini black holes will be stable is because I am advancing a revolutionary new model, the Dominium, that suggests that mini black holes will stay stable as voracious matter compacting beasts. Debate has been hot and heavy on my Scientific American blog. http://science-community.sciam.com/blog/Hasanuddins-Blog/300005039 I invite anyone to come on over and join the "fun." You wouldn't believe some of the harsh words that my detractors have against me. The funniest thing is that the people with the harshest words adamantly declare that they have never read the model. Go figure? Of those who have read the model, they have nothing but positive things to say...though they all hope that I am wrong about the stable mini black-holes, or, if I am right, that LHC can be stopped in time.
If you do chose to join in the discussion, please read the model first. You can download the half-version at http://www.sendspace.com/pro/dl/u56srb or you can purchase the full book (the paperback is more complete) at online bookstores
The issue is that when the black hole becomes small enough that semiclassical approximations don't hold any longer it could be that either the black hole becomes unstable to dacay into photons, or that a "smallest" black hole state is obtained. This would be like a new elementary particle - it has even been suggested that elementary particles are actually microscopic black holes.
Thinking about this, another question that arises is whether a stable microscopic black hole can accrete matter faster than it radiates it back as Hawking radiation. Remember that Hawking radiation is more intense the smallest the black hole. It's possible that matter around Earth is not dense enough for a microscopic black hole to accrete and grow. We have met the enemy, and he is us — Pogo