Quoted from "Thutmose"
Actually, based on the strict definition of a black hole, the LHC or even the RHIC could probably easily make them.
The problem is the stigma attached to the term "black hole". If the black hole is smaller than an atom, it will decay so quickly that it can't do anything, so even if the colliders make them, they are in no way a threat.
For antimatter production, you would probably want either a hadron collider or a lepton collider, where the former has the advantage of attaining higher beam energies (less cyclotron radiation losses) and the latter has advantages of more control of the beam, which results in higher beam intensities (electrons are lighter, so easier to focus).
The problem would be the absurd amount of energy needed to run the accelerators, and the absurdly high beam currents needed to make any sizeable amount of antimatter from them, you would probably at most get 30% efficiency (assuming using ultra high tech stuff we can't possibly make now), which ofc means you will not be using the antimatter as a fuel source for main power, but as a fuel source for weapons or portable devices.
To get the beam currents needed, you would probably have to use a few thousand or more smaller particle accelerators in parallel rather than one large one, for a good basic example see http://en.wikipedia.org/wiki/Manhattan_P…etic_separation
To make antimatter, rather than running a uranium beam through a mass spectrometer, you would collide either proton or electron beams, where the electron beams need a minimal energy of about 1MeV and the proton beams about 2GeV.
Hawking Radiation at it's finest; preventing the black holes made by massive particle accelerators from being able to affect much of anything.
Now, real doomsday usage of the LHC would be if they managed to accidentally whip up some strange matter. Shit would turn the whole planet into one big strangelet. And likely more of our solar system if it managed to shift the earth enough to screw up our ability to not head straight at the sun.
But yeah, the LHC has likely created over a dozen black holes already. But no strange matter, so yay. We're not all dead.
Thing is that all depends on whether nor not strange matter is stable, which is still highly questionable, considering that it would be the first* case of something containing anything other than the lightest flavour stable.
Also, current observations of neutron stars indicate that strange matter is not stable.
If strange matter were stable, then it should be more noticable, and given that it would interact with neutron stars.
*Neutrinos don't count, as they have a bad habit of changing flavour, so don't really count as "stable".
But if the anti-matter could be made, it would destroy itself pretty quickly, producing a crazy amount of energy. But, to get the anti-matter, you have to use the electrons, protons and neutrons to get the prositons, negatrons and the antineutron. Getting these particles could be pretty hard ingame, if that was even possible.