Since you are into stocks and for purposes of quick liquidity, consider gold and silver exchange traded funds. That's how I played gold several years ago.
They do have some nice looking designs but in my experience copper is so reactive that they usually end up looking horrible within a few months.
Cents were 95% copper up until mid-way through 1982. 1982 cents should be weighed to sort the coppers from the zincs. Every cent 1983 and newer are zincs. I have a 5 gallon bucket of copper cents not quite worth the space or back breaking hassle of moving. It's an addiction worth more in enjoyment then anything else. Save your money and buy silver.
Unless you're a very skilled stock picker, I'd run as fast as possible away from owning individual miners. I've gone down the road of Cliffs Natural Resources, Stillwater Mining, Iam Gold, and Newmont Mining. I thought, "Hey, they're 75% off their highs, how much worse can it get?" It got worse. I got my @$$ handed to me every time. If you must, stick to the broad indexes like GDX. I'm in it, but I also know I'm playing with fire. Same goes for energy stocks. I went out and bought the little unknowns that boasted huge returns only to get wiped off the map when things went south. Good example is BBEP. I've taken my lessons and moved to high quality names or just bought the index instead. You'll live longer that way. You can get into an $80 stock at $20 and feel like a genius. That is until it drops to $5 and you're out 75%.
The only mining stock that appears to be halfway solvent is Freeport McMoRan. Do I own it now? No. Do I plan on buying it? Not until there is a MAJOR turn in commodities. Carl Ichan apparently thinks it's nearer than we think because he's buying it with both hands. I don't agree. Of course, he can lose a billion here and a billion there and what the hell. The many "dead cat bounces" that oil has provided on its way down dictates extreme caution now.