Ever watch this show?
http://www.history.com/shows/america-unearthed/cast/scott-wolter
He had some thought provoking stuff. Primarily concerning ancients discovering America prior, in some cases way prior to Columbus, Vikings.
I've watched some episodes, using the History Channel "unlocked episodes" option via the Roku. I enjoy the show, but he's not too on the ball regarding prior work over some of the things he investigates (those lead crosses in NM were debunked by Barry Fell over 30 years ago, for example). His trip to Isle Royale and the Kewanaw Peninsula to look at the 5000 year old copper workings brought up the Newberry Tablet, which I'd not thought about in years, and led to this topic. I've been reading Gavin Menzies' book about the Minoans for some while now, and he discusses the copper mines as well. Menzies' books (I've read in just two of them) remind me of that old saying, when your only tool is a hammer, all problems begin to look like nails. :')