The reality is more prosaic. First of all, mini black holes at
the LHC are an option only if one of the theories of "large
extra dimensions" was in fact true. But of course, these
theories are only speculations so far. Second, should mini black
holes be created in high-energy particle collisions, they would
evaporate very fast, due to Hawking radiation. Though Hawking
radiation has not been experimentally verified so far, its
existence is expected in almost all theoretical scenarios
investigated (no matter where you go, you will always find
somebody who disagrees on something). But what would happen in
the (quite unrealistic) case that tiny black holes were created
at the LHC, and that they did not decay by the emission of
Hawking radiation? It's important to keep in mind that black
holes do not have some special "vacuum cleaner" property - they
just attract other stuff by the force of gravity. Now, the tiny
black holes that could be created at the LHC if theories of
large extra dimensions were indeed correct