Riffle size?

[russau]

this is why i make several different riffel/expanded sections to fit the creek/gold that im working. i travel around so nothing is the smae where i go.

 

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[fredvoris]

I am changing the riffles on my 4" Keene 3 section dredge because there is no compromise that allows both section 2 and section 3 to work properly. Section 2 has 1" high riffles shaped like the ones pictured on the high banker in one of the first replies to this thread. Section 2 has very small riffles for fine gold. To achieve a compromise I am thinking of reducing the size of the section 2 riffles. What type do you guys think would be best? how high should they be? how far apart? what angle [inch/foot] is best for the type riffles you suggest? Thank you in advance Fred.

 

[Hoser John]

I've been working on hydrolic riffles for years and gettn' much closer,will post info when done for your fun. Self cleaning is indeed hard without gold loss. But all good things comes to those that never give up as every failure is a success as options removed and closer to the real deal-Over/under was a pain to engineer and perfect and tri-jet, baffle inducted pressureized chamber ,flared jet technology cost us more than my house!!!John

 

[Macgyver12]

I read your articles about the sluice and I'd like to build one to describe the world in search of gold. But I did not find any dimensions to build one.
Can you me the dimensions of the sluice and the dimensions of riffles please?

 

[bill-costa rica]

john
i have been woking on hydraulic riffles for my dredge for a number of years and i have something i like. my sluice has a number of ways to catch gold. first off is 1 and a half inch bar riffle for 18 inches for the course gold. then 6 feet of armour weave riffles covered by rolled flat expanded metal and last but not least 40 inches of hydraulic riffles run at 6 to 10 lbs of pressure depending.... the hydraulic riffles are inclosed on the top and only 1/4 minus goes over them. the amount of water is reduced greatly by being inclosed. i guess you could call the hydraulic riffles pressureized. seems to work pretty well... i have a lot of gravel running thru this sluice.

bill/cr

I've been working on hydrolic riffles for years and gettn' much closer,will post info when done for your fun. Self cleaning is indeed hard without gold loss. But all good things comes to those that never give up as every failure is a success as options removed and closer to the real deal-Over/under was a pain to engineer and perfect and tri-jet, baffle inducted pressureized chamber ,flared jet technology cost us more than my house!!!John

 

[Macgyver12]

Can you give me a diagram of the sluice with the instructions above dimensions. As the dimensions of riffles.
Thanks

 

[Gelmac]

This is what I learned yesterday at the GPAA gold show. Sluices are not made right!
They are best at placer gold recovery, but share a common design flaw that reduces maximum gold recovery.

The purpose of a sluice is to separate all sizes of gold from the other material such as gravel, sand, dirt, etc. trapping the gold and eliminating the waste.

To achieve that task a sluice needs to:
Create the proper vortices to allow the different sizes of gold to separate and drop out of the water flow to then become trapped for recovery.


Here is the main design flaw in sluices: The water flow over the riffles is going the same speed as the water flow over the expanded mesh. Because the expanded mesh is located in the same part of the sluice as the riffles there is no way to adjust the water speed separately. * see below.


Expanded mesh is best at trapping small or fine gold. But for the proper vortex to form, the water speed needs to be a lot slower than for riffles.

Riffles are best at trapping larger gold but to form the proper vortex the water speed needs to be a lot faster than for expanded mesh.

Riffle height should be no more than 1" tall and then the top lip not extend forward more than 1/2 inch and the 1/2 inch lip should be elevated 15 degrees above perpendicular to the sluice box and the riffles should then be only 2 inches apart. any more or any less apart will not create the optimum vortex.

Here is a link where this info may be verified : http://ygsftp.gov.yk.ca/publications//tech/placerrecovery.pdf

Old Thread revived !

This one works : http://emrlibrary.gov.yk.ca/ygs/mining_technology/placerrecovery.pdf

A better design (IMHO) would be in the lines of the Advanced Mining Equipment (CC690 Power Sluice) : Advanced Mining Equipment Power Sluice / Highbanker

Just to give you some ideas for this type of sluice design, I have no commercial gain of mentioning this equipment. As they stated on their website -see above link- : "one we designed based on Canadian government/university research from Yukon placer gold recovery operations." Now (Popandsonminers) praises this design for gold recovery.

I don't own one of these, so anyone who owned/used such unit could possibly give us a feed back about it's performance .