Thanks everyone for your generosity, I will check out the tickers supplied as my time permits.
I am less attracted to exploration and discovery plays in copper than in other metals;
I prefer advanced development or producing assets, but often there are multi-metal deposits that are worth looking at. I am specifically interested in Australian deposits, though South America has been popping up a lot.
Thanks for reminding me about BHP. Sometimes the obvious choices get missed, have to re-visit BHP.
I usually stay away from diversified big caps, unless I feel we are in a long-term secular upswing or bull market. I think copper is just at the beginning of such an upswing.