The Dry Sluice Worked For Gems...

[Jim in Idaho]

Well people, I think I've finally accomplished what I set out to do 8 or 9 years ago. I think I've built at least a dozen different machines in an attempt to get something I could use to recover diamonds and indicator minerals without water. Maybe twice that many. The number of hours I've spent thinking about this are countless. I had an idea that my dry sluice might finally hold the key. I recovered a few tiny garnets with the larger model in Wyoming last summer. But, I still wasn't convinced. The riffles weren't quite right, and tiny gems are easier. Today, using the backpack model which only has a 7" x 24" sluice, but with the new riffle design, I put 8 1/4" alumina abrasive spheres in 3 gallons of mixed dirt/gravel. About 20% gravel, and 80% dirt/sand.silt. The alumina spheres have a specific gravity of 3.5. In most of the west the SG of the background material is about 2.5. I've never before managed to separate anything of less than 10, or a 1:4 ratio. All 8 stayed in the sluice. That, for me is a real accomplishment. I think the combination of that riffle, and the particular motion I designed into the sluice has finally overcome the "Granular Convection" problem. This is going to open up a lot of gem country, where previously I had to screen, classify, haul buckets of gravel to a water source, to use the Pleitz jig, etc. I'm a happy camper this afternoon. And, it should work even better on heavy metals. I'm going to apply for a Provisional Patent to start with.

Jim