Colliding beams with block not the same as colliding beams
The beam dumps did not cause 3.5 TeV collisions I'm afraid.
If you have two particles with the same energy (say, 3.5 TeV) and they collide head on, the energy in the centre of mass frame (the frame where reactions happen in this case, but that's a bit crude) is just the energy doubled i.e. 3.5 + 3.5 = 7 TeV
But if you collide a beam at high energy with stationary particles (the 3.5 TeV per proton beam hitting the graphite beam dump), the energy of possible interactions is much less (\sqrt{2*11.19 GeV * 3.5 TeV} = 280 GeV), where 11.19 GeV is the mass-energy of a carbon atom.
More details here:
http://www-bd.fnal.gov/public/relativity.html
Biting the hand that feeds IT
