New Zealand Gold Prospecting & Metal Detecting Forums Archive

I found fine gold is best caught when there is as little turbulence as possible in the water flow. So riffles at the start to catch the coarse gold - then expanded metal held down by 8mm rods across it to keep it flat. Then at the end a few more riffles to try and catch those larger but skinny flakes that seem to flip out of everything. Miners moss under all of it. The less turbulence there is, more chance the gold has of dropping down through the water/mud and being trapped, each time the flow is flipped over, fine gold ends up near the top. I also like a draped bit of canvas or thin rubber to reduce surface tension. I also vary the gap between riffles, larger gaps are better at self clearing but will hold larger pebbles, I like hungarian style but not very tall, shorter is better to reduce the boil and flip effect. My preferences and the reasons for them - not everyone will agree. NUGGY

I was pretty keen to give allen trees system a go but found my sluice was working really good so didn't bother but if your looking to try something different it could be worth a go
https://www.youtube.com/watch?v=fX-B4Oj7YfM

Hi..yes he does make the flared sluices but not on his 8 basically he has a sump undernearlth your undercurrent section then he has a 3" Venturi that sucks all the material that falls into the sump that all gets pumped into a seperate sluice that sits ontop of the main sluice...watch the clip he explaines how it works .

dont see why it wouldnt work but 1/2 Inch isn't really fines !!
These systems have been around for a while think 30 odd years mite have been called "the American dredge "!
I was thinking of trying it out as my gold is mostly fine or flat flake but I don't have much black sand so recovery is pretty good...Iv got 5mm punch plate over the undercurrent section which is 740wide by 600mm

I AM FAIRLY NEW TO THIS. But I have a small high banker that I have used in Alaska a few times with my son in law. We were working public areas and it was really fine flower gold. I fond that the Gold Hogs Matts did a very good job of capturing the fine gold. I using a Gold Hog Mini, with a keene stream sluice tacked on the end, fitted with more gold hog matts.

It caught the very fine fold that was up there with no problems. We tested the tailings for losses, and there was very few losses.

Their stuff is expensive, but well worth it.

If nothing else, he has a lot of information he posts. He is also very responsive to queries. If you are having a problem with his mat, he will work with you to get it resolved.

He has a new material to be used for the washing and cleaning stage that I am going to be getting. Cleaning the cons is always a challenge. he looks like he has a good mat that will work with a recirculating bilge pump that will work well, even for fine fold.

I've recovered a bit of shotover flour gold with a 6 inch dredge. Found the best thing to do once all set up was to check the amount of air bubbles in the box. i ended up duct taping all joins in the hose and connections so no air at all was getting in. a air bubble less box caught the most gold of course. you can't catch finer gold than that at the shotover round here. of all the gold that tried to get away it is the bigger flat flaky minute gold that tends to flip away if any does. just need to have correct riffles and mat set up. same bits are what tries to escape at cleanup too. advice to anyone new is test your tailings periodically to see what you are losing. do the same at cleanup to see what if any you are losing. and something i quickly found in relation to miners matting - once you've cleaned the matting dry it fully then shake. a pan up i did i got another gram of very fine stuff. at $50 a gram it is well worth the extra time to do this. otherwise if i was going out often i just left it in the matting and stored the mats in a tub.

i've been tempted to try some of the gold hog mats in different combos i the dredge box but they're not the cheapest. would love to hear how anyone else has found these.

It seems the problem with the 8" with the 28" sluice, is that it is flowing too fast and deep to catch the small flakey gold using regular configurations...

Tried one rebuild but to no avail... have another scheme in mind, using expanded mesh I am about to try. Both Keene and GH agree on this so I will make the mods and try it out in April

This is the stuff I am trying to catch... very thin and flakey.

Edited by user Wednesday, 25 March 2015 9:57:37 PM(UTC)  | Reason: Not specified

Have you tried putting in 'boil boxes', we had them at the start and end of our rifle boxes, with water swirling in them or through them they do catch alot .

Hears the link to the new 49ers le trap style underflow...
http://www.goldgold.com/the-size-of-riffles.html