Gold
would become more abundant in the event of an economic collapse. At least over the short to medium term.
Think of how many wedding bands, gold watches, necklaces, etc. would be melted down and sold for scrap.
The world extracts around 3800 tons of gold a year. The above ground supply of gold is well over 160,00 tons.
We only increase the global gold supply by around 2% per year through mining. That's not a big increase.
Moreover, much of that gold is mined in places that wouldn't necessarily collapse at the exact same time as the United States.
Even assuming no new gold mining (a ludicrous assumption but whatever), the American middle class as a large gold stockpile that it would be rapidly converting into groceries in the event of a major economic depression/collapse.
It's a similar case for copper. Much of the world's copper is used in industrial processes and manufacturing. This economic recession created a huge surplus of copper as demand for copper dropped.
Even if we stopped extracting as much copper from the Earth, demand would drop rapidly as the electronics industry collapsed.
If we aren't building lots of new houses and we aren't producing a lot of new cars and electronic toys...copper demand will crash.