Riffles and sluices

[micropedes1]

Like you, Russ, I have a full sized machine shop at my disposal. But I was looking for a way that a regular Joe could build 'em cheap & easy. This works well although kinda heavy. Vary your riffle spacing and depth to suit your needs. Don't be afraid to experiment and throw something different in there. Zooka always argued with me to use avariety of recovery methods. Why build a box with all one kind/size riffle throughout? If it don't catch in the first few feet, what makes ya think 8 feet of the same thing is gonna work better!

(if the pics are too large, size 'em down for me, Russ. Hard to fix on a phone)

[russau]

haha bigger is better for these ole eyeballs! i like the idea of trying something new! i just finished redoing my o/u sluice/flair for my 4 in dredge out of ABS plastic. it was alum.@ 65 lbs. and now its 30lbs with the same items in it except i got rid of my miners moss and replaced it with Shaw carpet that John Hoser suggested to me while we were in Wyoming last year! THANKYOU JOHN!

[micropedes1]

Russ, I have built these drop riffles in aluminum, vacuum-formed ABS, fiberglass, and finally polycarbonate. This last is a way that all can do it with minimal building skills. For those that want to give this a try, don't get discouraged if your first attempt does not work as expected. Mine didn't work right either. Ya got to balance the drop distance with the riffle spacing.

By the way, this one is set up for tiny gold in Alaska, mostly 30 mesh. And it is operating under 1/8 inch punchplate. Bigger gold might need more aggressive riffles and a wider spacing. And just in case something screws up, there is still Nomad under expanded, and some Hungarians farther down the sluice.

[micropedes1]

Oh, and here is a pic of a finished panel. As to recovery....lets just say that I have faith in them. Recovery pics later.

[russau]

it looks good enoughto maybe have yourself a side line to make some $$!

[Sierra Sam]

I really like the idea of using fiberglass to fabricate most any configuration one could imagine. Then I began thinking of cleanup.
Dropped riffle setups must be a pain to clean up.
I've been up in the Sierras this past week taking advantage of the water flow in a little creek I work, which is usually dry as a bone 'bout now in any normal year.
After a day of digging and "normal" back-breaking work, I can't say as I look forward to clean-up.

I used a two-sluice setup this past week. I used my modified Keene sluice/highbanker as the primary, and an older, and wider, non-flair rig as a catch-all. After seeing gold-bearing quartz flow through my sluice, a catch rig seemed logical. My second sluice has homemade steel riffles which are closer spaced and more vertical than the stock aluminum ones that came stock, and which began to fall off after a few seasons.

OK, ok, I'll get to the point. The first Keene sluice has stock, removable riffles. I like the removable riffles best because clean-up is far more easier than the second sluice, which has hinged riffles. Both rigs are decent, but I prefer the removable. With a dropped riffle setup, cleanup must be a pain, especially after every one of your muscles and bones aches after a week of shucking rocks and pulling boulders, shovel full after shovel full. That's about the time you start thinking about backhoes and big trommels

[umpqua_gold]

Very, very interested in this. Keep the photos coming!

[micropedes1]

Sierra, you are using a different kind of beast entirely. Raised riffles operate best when you have sufficient velocity to create a vortex behind each riffle. This has the effect of sorting heavies farther and back under the riffle. But it also throws your very fine gold back up into the moving water stream, sometimes to be swept away. Drop riffle allow heavies to hug the bottom in a more laminar flow. Lower velocity. Better fine gold retention.

I do not use a shovel. These riffles are going in a 10" dredge.

[Sierra Sam]

Micro guy -
So, what's clean-up like?
Don't they load up quickly? And how do you get "low flow" with a 10"? With Width?

[pickaxe]

Actually, in researching "drop riffles" I came across this on the New 49ers. A bit complicated, but if you have a lot of superfine gold it may pay. I play mostly on the Arkansas river, known for maddeningly fine gold, so my interest was peaked.

http://www.goldgold.com/stories/doubles ... cation.htm

And the letrap sluice which the system is modeled after is highly regarded.