Flying fine gold

gravelMaster · Feb 2, 2026

I am in the process of constructing a unique style for classifying fine gold for a sluice. But there is a slight problem that needs to be resolved - the bouncing/ejecting of fine gold particles off of the sluice, caused by rocks, large gravel size, etc. vibrating the sluice. What are the size of the holes in a perforated metal plate would you recommend? 1/8", 1/4" or 3/8". Your replies are needed to help in the design.

Regards

Assembler · Feb 2, 2026

gravelMaster said:
I am in the process of constructing a unique style for classifying fine gold for a sluice. But there is a slight problem that needs to be resolved - the bouncing/ejecting of fine gold particles off of the sluice, caused by rocks, large gravel size, etc. vibrating the sluice. What are the size of the holes in a perforated metal plate would you recommend? 1/8", 1/4" or 3/8". Your replies are needed to help in the design.

Regards

There is going to be losses no matter what. If you are going after fines the 1/8" sounds good.

High Etiquette 009 · Feb 2, 2026

What is the material that you are using? I would suggest classifing down thru 50 or 100 mesh if it is truly fine gold. Cheers!

BoulderTroll · Feb 2, 2026

When I'm working places where I only get flour gold, I classify to 1/8. Only need to go bigger if you think you'll actually find gold larger than that size.

gravelMaster · Feb 2, 2026

High Etiquette 009 said:
What is the material that you are using? I would suggest classifing down thru 50 or 100 mesh if it is truly fine gold. Cheers!

Most likely the glaciers from Canada deposited fine gold. The present day ground was almost a mile under the glacier. I'll be trying to capture trapped gold from the bedrock cracks/fissures in the numerous rivers that we have in upstate NY.

BoulderTroll · Feb 2, 2026

gravelMaster said:
The present day ground was almost a mile under the glacier.

That's an interesting fact!
Where I'm at (western Washington), in some spots there's 1000ft of glacial till before you get to bedrock. I just get to play in the overburden.
Good luck!

gravelMaster · Feb 3, 2026

BoulderTroll said:
That's an interesting fact! Where I'm at (western Washington), in some spots there's 1000ft of glacial till before you get to bedrock. I just get to play in the overburden. Good luck!

BoulderTroll said:
That's an interesting fact!
Where I'm at (western Washington), in some spots there's 1000ft of glacial till before you get to bedrock. I just get to play in the overburden.
Good luck!

Just what I've been doing in the past... until a Canadian friend from Quebec told me where he pulls out the trapped gold with a 2" suction dredge (not in a trout stream).

PickAxeCA · Apr 19, 2026

Don't classify to any smaller than 1/8" for a sluice or highbanker. The reason is the screen can get clogged with rocks, organics, etc (aka blinded). The time to classify smaller e.g. 20, 30, 50 or 100 mesh is during cleanup at home.