cool idea
Just a crazy thought....I was thinking about how the gold would settle or would it walk up the side of the material on the bottom. Made me think of how a spiral gold wheel works. All the gold settles to the bottom, and only walks up due to the spirals catching it. Which led me to further think....what if,,,WHAT IF....the back of this drum instead of being smooth, had spirals just like the spiral wheel concentrator? The combination of the classifying action and a spiral gold wheel is what I see here. Would take a bit of tweeking, but Ill bet it would work.