Probably not a lot of gold in there and anything you got isn't visible any longer. By melting the copper base the gold dissolved into the copper and is now a part of the alloy.
I've thrown more gold than that in the trash. Isn't it so, Nick? :lol:
The ribbon cables are usually not very high yielding so chasing after this gold is going to cost you more than the monetary worth of the gold. But if you succeed to recover it you will have gained knowledge.
The first thing I would do is to incinerate the garbage. What this does is it burns away any organic matter and carbon that might affect your chemistry. In mining circuits, carbon is called a preg robber, it locks in gold in the carbon. So incineration until any coal left is turned into ash.
After that you could probably select between a couple of roads. Which one that is best for you depends on your proficiency, what the major contaminants are and what chemicals and equipment you got available.
If I had a good supply of nitric acid I would then go on and dissolve the copper, which would leave the gold as tiny dust particles, probably looking as black ink if you could get enough of it and fine enough that it could pass through most filters. Patience and decanting could rid you of most of the copper. Then put everything metallic left into solution with aqua regia... or just adding HCl, the remaining nitrates will be enough to dissolve the little gold that is left.
Filter out any sand, then precipitate the gold from the solution.
If HCl is the only acid I could get then I would start with boiling the incinerated material in HCl and wash it off. This will remove some contamination from the incinerated soil and dirt. Then HCl + time or a tiny bit of hydrogen peroxide to start a copper chloride leach. With or without a bubbler the copper chloride and acid will turn all the copper into copper chloride, leaving the same black gold dirt with the sand. After the copper is dissolved, decanting and washing with HCl will remove the dissolved copper. Then HCl + hydrogen peroxide or chlorine (bleach) will dissolve the gold.
Filter out any sand, then precipitate the gold from the solution.
Any liquids pored off should be tested for gold with stannous of course.
Well, this is the general way I would tackle this problem if I really wanted to chase a couple of dollars worth of gold just for the challenge. And as always, there are more details in each step that I didn't mentioned, but this post is long enough as it is.
Göran