The article says 3,000 years ago so around 1000 BC. So this would have been after the collapse that was around 1200 BC.
You’re right, sorry for skipping over the “ago” rather than “B.C” OTOH, if you use the Bible concordance, iron is mentioned as being used in objects some time before 1200 BC, according to the time line presented in the 1200 BC hypothesis I saw.