(I wonder why they didn't take the opportunity to rebrand themselves as Porphyry Fox, or Copper/Gold/Silver/Molybdenum Fox, or perhaps just Multi-metallic Fox. Are they going to be forced to search for copper forever?)

Because they want to keep the name. The name has value. It's not about what metal they're looking for. It's about the history, accomplishments and reputation of CUU and the team.