Del & Roger, I am convinced that they are not struck at the US Mint. The combination of being the weight and thickness of a zinc cent with the large diameter means they are not the zinc alloy, they are something lighter, maybe aluminum and copper plated? The odd slotted rim is not something you would expect from the mint either. My belief it that they are Henning-type home struck, using a hand press, perhaps in the Northwest US, since that's where they are showing up.

They are extremely interesting though. They are definitely collectible.
I wish I could find just one. (well, maybe two, with different dates)