> There's places were "mining" copper from street poles is already profitable, and wire theft is a huge problem.
I don't think that's really "profitable" in any way besides theft being profitable. People who do that typically cause orders of magnitude more damage than the money they get for the scrap.
IIRC, it's already profitable to "mine" copper from pre-1982 pennies. IIRC, those contain something like 2-3 cents worth of copper, at current prices. I saw a machine once, online, that would automatically sort out copper pennies from zinc ones.
