Gold Hog - Position of
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Position of vortex…
Why is vortex position important?
Because in order to determine proper riffle spacing, you need to know your
own VIA. (Vortex Impact Area). Too close and you’ll disturb the vortex. Too
far and you’ll be wasting working space. (With passive matting. Open
space is actually good with ACTIVE matting.)
The front of the vortex will be not too far behind to the very top (tip) of
the riffle (Shown as red dot). See below. This does change a bit based on
water speed and angle of the box. I do want to point out that each
prospector needs to understand THEIR OWN set up as this varies and is NOT a
constant that we can give.
The nice thing about the above illustration is that you
can apply this knowledge to just about any riffle style or shape now that
you know it. Where ever the very top edge is, the vortex will start not too
Now this should also open your eyes as to HOW MUCH “material” is being
“held” by your riffle. (Yellow zone) Here’s the important part though that
opened our eyes.
(Opinion based on our findings.)
Increasing the YELLOW zone, does NOT equate into more gold retention
in most cases. It simply means you are holding more GENERAL material
of all types and weights. (We saw TON of light material packed in some.)
Head scratcher / note…
Let’s look back at our “knowns”. Gold is HEAVY. Gold “usually” hits the
matting / bed between 5-14 on the vortex. Therefore, a LOT of gold never
gets PUSHED back into the YELLOW zone. Therefore we again STRONGLY STRESS
the importance of a good HOLDING / CAPTURE matting. Keep in mind that the
“throw down zone” can be very active and turbulent, so allowing gold to
“hide” in dead zones WITHIN this area is critical. DO NOT expect gold to
AUTOMATICALLY be pushed back into the YELLOW zone.