You want a tour of a warehouses full of copper ingots? I mean plural, warehouses, because you’ll find them near any big industrial user of copper. But only if you can find dozens of warehouses will you have any clue as to how much is kept in reserve.
The important thing is how few businesses control all that copper.
Who needs a copper warehouse. It will not rust. I read the Chinese leave copper stocks out in the open if they cannot house it.