Copper is getting expensive to mine. If copper $ goes down, lots of mines will be shut down.

Average cost per pound of copper is around $1.50 (this was back in 2012 I read). or more.

Then you have countries such as Indonesia where they don't allow Freeport to export concentrates until recently.

Some mines having delays but were suppose to be coming online. (Red Chris, Cobre Panama, Rosemont).

Aside from the demand, copper supply may be a problem in the future.