Haven't heard about that, but I'm not quite sure what the purpose of a vertical particle accelerator would be.
Most particle accelerators (like the LHC) are used to further our understanding of particle physics and high-energy physics, particularly focusing on the collisions of sub-atomic particles.
There are already linear particle accelerators that are used to investigate nuclear physics and isotope production, as well as the collision of heavier nuclei.
I'm not quite sure what a vertical particle accelerator would accomplish, and I'm not sure building one would make sense. CERN just recently announced findings pertaining to the types of decay of quarks. If confirmed, their discovery would violate our current understanding of physics and the standard model. I think if anything they should continue investigating that.