Seafloor massive sulfides and manganese nodules also have significant amounts of copper.
But I would like to see improvements in copper recycling and in breeding of copper hyperaccumulator plants.
It's also an asymmetric process: getting setup for less pure ore is capital intensive, but once you are the available abundance of your new feedstock can push prices lower then they were before.
Copper is 60 ppm of the crust. As long as the price keeps going up, we'll never run out.