If these yards only have one location, they are just selling to the national
scrap metal businesses, or very large operations. SIMS, Schnitzer, Omnisource, etc...Upstate Shredding in your area does a lot of non-ferrous.
Next, although you do have a considerable amount of copper, it really is a drop in the bucket to the big processors. This is also a one-time shot. It's not like you'll be bringing this amount in every week. Call the larger yard of your choice, and ask to talk to a buyer - they might bump you up pricing levels; they might not. Usually you need a business account set up, not just someone calling out of the blue to unload a whole bunch of copper.
Just my opinion, and others will probably chime in.
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