I work with someone who used to work there.
Apparently they showed a screen-shot of some software he'd written on the news. He was dead chuffed about it.

As I understand it, any black holes that could be potentially formed will collapse in on themselves instantaneously anyway so theres no risk whatsoever. (Google 'Hawking Radiation' for the theory)

As with all science though, the proof is in the testing. The fact they've managed to contain the beam is a big achievement. You wouldnt be too popular with the cleaners if it punched a hole in the side and blew one of them big magnets to smithereens.