You must not have read the article. From the article It appears that copper was initially loaded into the first shipment of containers, before being surveyed

You must not have read the article. From the article It appears that copper was initially loaded into the first shipment of containers, before being surveyed by an inspection company. Seals used to prevent fraud were then affixed to the containers. The product was real and loaded into shipping containers. After it was inspected and sealed the fraudsters switched out the cargo as it left the port. There was even Insurance fraud with some group providing fake Insurance coverage (one real policy with the rest being forgeries) for the seller. These firms aren't fools, they do this everyday and understand what to do, shit happens.