Assuming it got loose, and I have no idea if a micro black hole can be contained, presumably some much like the scenario I described above from a sci-fi short story: it would fall from the surface towards the center of the earth, and keep right on going towards the other side, and then swing back and forth repeatedly and steadily, accumulating mass as it went, hollowing out the earth. Eventually the whole earth would collapse into it and we'd all be killed. The earth would become a low mass micro black hole in orbit around the sun, with the moon in orbit around it, with everything continuing much as before, except that the earth as we know it would be gone. Not a pleasant prospect.
This is what was most likely on the minds of those in charge of the research grant money and particle accelerator time. I was merely relating an article on similar experiments I had read 5 years or so years ago.
This stuff is all kinda 'out there' and I'm sure they just said, "Whoa. Wait a minute", before allowing the research to continue. If there was a small infinitesimal chance (ie. NOT absolutely zero) of this happening, they wanted to err on the side of caution.
"On the Borderland of Sol" by Larry Niven. You charge the hole using an ion rocket then use magnets and static E fields to move it about.
Then you use it to pirate nullspace ships, since of course a null drive cannot operate near a singularity.