By Jim in Idaho
I've been trying to come up with a unit to recover gems dry, but finally realized that the "granular convection" problem can't be defeated. In the process of building and trying various ideas, I came up with this unit. While the dry recovery of gems requires some very tight classifying, and thus isn't practical, I tried it for gold, and was simply amazed at its abilities for heavy metals. I have tried it on all sorts of raw materials, running bank feed at roughly 2" minus, and have yet to find a material it doesn't work on to one extent or another.
I ran it dry...no water, on damp material at the LDMA Blue Bucket outing near Baker, Oregon a few weeks ago, and recovered flour and black sand from old tailings from previous outings. Running wet, the day before, on new material I recovered very near 100% on black sand and gold in front of several witnesses. They suggested re-running the tails, and zero black sand, or gold was found. Last weekend I attended a local club outing at Salmon, Idaho. The material was a heavy clay with lots of rocks....not a fun material, at all. At the common dig, one of the guys next to me, running a highbanker, mentioned that my little unit was handling the clay really well. I was the only person running 2" minus directly into the machine, and the rocks were agitating the material so the clay broke down, and the rocks were mostly clean before they went out to tails. The day prior to the common dig I went down to the locale the common material had been hauled from, and ran the material dry. This was a nasty, damp material. I expected nothing and was surprised to see both black sand and gold when I did the cleanup. Certainly I lost quite a bit, but any recovery working dry from damp material is an accomplishment. This unit works wet or dry. Very little dust running dry. Very low water requirement when running wet...roughly 50 gallons/hour.
The full utility US Patent has been applied for.
You can see the prototype running at Bonanza Bar on the Snake, along with pics of the recovery here:
Hi there RR, All this gadget is doing is mechanically classifying material into a gold pan. Nothing you couldn't do with a manual classifier over your gold pan which you could possibly get away with. I know with my sluice boxing I made & use a bucket classifier than can process a lot of material pretty quickly to feed down the box.
Clean up time
Good luck out there
Super Cool! If it can handle the punishment of Hardcore Diggers? Enjoy! Cheers, Ig
By Steve Herschbach
I tripped over this extensive article, available as a free download. Here is the abstract:
The article sets out to clarify the special character of the North American gold pan and why it remains so popular – in spite of widespread dissatisfaction and many modifications and innovations. The North American pan is distinctive in being circular with a flattish floor ringed by an outwardly sloping wall. Its identity is confused by over-use of the terms 'pan' and 'panning'. The North American pan gyrates in a distinctive orbital motion driven by both hands of the panner. Although many other motions are resorted to (tapping, to-and-fro, tilting, and tick-tock), it is the orbital motion and flattish floor that together distinguish the pan from most other hand-held gravitational devices. In spite of its enduring popularity, no scientific tests have been published on the North American gold pan or for any of the innovations covered by 30 US patents awarded since 1861. It remains unclear if the North American gold pan is more efficient at recovering fine gold and flat gold than is a lotok, batea, dulang, ninja bowl, grizzly pan, mat, bucket or any other sort of hand-driven gravitational device. Some innovations are long-forgotten but merit attention. For instance, bars to keep the panners hand clear of the water, cables to hold large heavy pans, and several pans designed for panning without any water. Traditionally the North American gold pan was a combined digging and washing device, but today most models are not designed for digging and require a spade to be used.
Gold recovery in Gold Pans -the term... (PDF Download Available). Available from: https://www.researchgate.net/publication/313562132_Gold_recovery_in_Gold_Pans_-the_term_'Panning'
I have been working on this for a couple weeks. It's a collapsible, customizable, self-contained, super light, 3D printed sluice box! I know there are other folding sluice boxes, but none of them actually fit in a backpack, or are light enough to carry in one hand. This solution would be EXTREMELY helpful!
I'm on my phone trying this, so when I get to my laptop, I'll write in a bit more.
So I'm currently in the CAD stage. I have a guy that does 3D printing for me, and his machine is limited to 12"x12"x15" so I might have to shrink the size of the project down to fit, as I don't have access to, or can even afford, a larger 3D printer.
I have this up on Patreon to attempt to raise some funding to start getting prototypes printed, and boost this project towards the finish line!
This is my Patreon page: