The tale of production of black holes at accelerators has evolved into the status of an urban legend. The succession of higher energy accelerators from Fermilab to RHIC at Brookhaven to the LHC at CERN has always been accompanied by fear mongers. It ain't so. I was at CERN last week and talked with colleagues at the ATLAS experiment. They would be overjoyed if they saw something like that but don't have any champagne in the refrigerator reserved for it. They are waiting for the Higgs particle.
As you know, black holes are enormously massive objects. They are usually hundreds of millions or billions more massive than our Sun. Astronomers are certain that one exists near the center of our galaxy. But to make them in the lab, no way. The forces and masses are not big enough.
For some information see: http://www.universetoday.com/guide-to-space/milky-way/the-milky-ways-black-hole/
It may be that particle collisions could create extremely
small black holes, of about the same mass as any of the other particles produced in the collisions. Some CERN scientists have expressed optimism about creating these:http://cerncourier.com/cws/article/cern/29199
They wouldn't be dangerous, since if they can be made by these collisions, cosmic ray collisions would have been making them all along without making problems. They should evaporate very quickly via quantum tunneling, called Hawking radiation in this context.
(published on 05/23/2010)