Check This Out. Drop Riffle Matting On A Flared Highbanker

[John-Edmonton]

A friend of mine from Adventures in Gold Prospecting and I were discussing some old designs that worked well 35 years ago in highbankers to capture flour gold. He liked some of the concepts, so he designed and built one and as per my request, installed some 1/2" x 1/2" square matting. So, the finished trial version is basically a drop riffle highbanker. It operates at about 1500 gph using a 2000 gph bilge pump tuned back to about 1500 gph to the point where the riffles don't clean themselves out. It is set at about 8 degrees.

Because my area has mostly fine flour gold, the hopper is screened very small. There are 50 drop riffles in the unit, and as mentioned they start out short and expand wider horizontally as they progress down the sluice. I used a Budweiser pull tab to compare sizes.

Inside the hopper is miners moss over small V matting, which captures a large percentage of gold. My first run showed it captured over 50% of my run. I may have had losses out of my sluice due to tweaking the angles and water flow.

It is Canada Geese birthing season. Looks like a good run on babies this year.😂

Underneath the 1/2" drop riffle is a V matting cut to fit in the unit. Because my concentrates are screened so small, they can be readily cleaned on the V matting, doing a great job of capturing the flour gold and getting rid of most of the blond and black sands. These super concentrates are now ready for back panning at home. So, I might as well do this step at the river, as I already have a source of water, a unit dialed into the right angle and matting in place to complete the task.

Here's my final clean up after about a 4 hour run. The unit has been called the "Wedgy" due to it's odd shape. My next trial is to run the unit without the drop riffle system and use only the V matting to capture the gold and other heavies. This is how we used to run some of the units 35 years ago to capture the flour gold. Running it on V matting allows the user in real time to see when the riffles are starting to fill up with flour gold, where on the sluice area matting and to also tune it efficiently in real time. Combining a high capture rate system in the hopper plus a properly tuned lower sluice should work well, with minimal amounts of concentrates. Dang, got to love retirement! I like the flaring principle although not new, it allows the gold to drop out where the right variables exist.

 

[Assembler]

My guess is the hopper is 10" wide by about 18' - 20" long with the v mat / miners moss over the first half and you use metal tools to help move the larger rocks out the backside?
Thanks for sharing the nice set up.

My guess on the screen mesh is about 12 mesh per inch being supported by the punch plate under the screen?

 

[Assembler]

What would happen if you try a much larger screen and punch plate over a wood / metal catch box sitting on top of the river gravel?

The idea is to just either rake or shovel river rock on top of the flat catch box then level a thin some what even layer over the screen then rinse the layer of rock then rake off the rinsed rock off into a convenient pile.
The result will fill up the catch box of flour material to then lift up to run through the sluice box set up at around 8 degrees. Any over flow of water is not going to flush away the heavies out of the catch box. Having a few different catch boxes will speed up the classification step process and cover a bigger area with out moving the catch boxes (just fill some plastic buckets from each catch box) for making a longer run time with the battery powered pump you have. My point is to reduce the amount of lifting all of the rock as much as possible to recover just the flour size (classified materials) rock.

I'm thinking the rubber v mat will work well however some testing will give you a better idea for your materials.

No matter what matting works good for you I'm looking forward to your results and again thank you for posting a great thread topic :-)

PS: I should point out that one can move each catch box after going down 4" - 16" in the gravel depending on your work style and the depth of the catch boxes. This way there is the least lifting of all of the gravel rock for the classification step freeing up your mussel power to then make the sluice runs when the catch boxes are filled up.

 

[Assembler]

There are some other methods to help out with the classification step that can be hard on the body that the old timers used however not popular today for a number of reasons.

 

[John-Edmonton]

There are some other methods to help out with the classification step that can be hard on the body that the old timers used however not popular today for a number of reasons.

I use a small brush to clean the screening in the hopper to prevent runoff. It works pretty good. With things getting classified so small, I can run the unit with a bilge pump with a low water flow (typical for drop riffle units) and my 60 Ah lithium ion battery lasts a long time.

 

[Assembler]

I use a small brush to clean the screening in the hopper to prevent runoff. It works pretty good. With things getting classified so small, I can run the unit with a bilge pump with a low water flow (typical for drop riffle units) and my 60 Ah lithium ion battery lasts a long time.

Good I'm thinking that a brush would be handy for moving any unwanted build up and lets the water flow through. With a larger screen and the same amount of stream rock placed upon the larger screen you may not even need the brush when rinsing the rocks. A large rake can help with the rinsing process step and without changing the tool flip over the rake and use the straight edge to remove the unwanted rocks.

Yes having a bilge pump that is smaller can run a long time on a battery for the sluice box set up.

Perhaps the work can be separated into two parts to increase the yardage of material per day or amount of time say over a few days?

The point is the amount of lifting of the overall unwanted rock yardage as little as possible and just lift the classified rock the height of the sluice box to run. The water flow is based on the bilge pump say full flow for just rinsing the larger rocks. A lower 3/4 flow is used for the sluice box that has given you excellent results for the fine classified rock / material.

 

[desertgolddigger]

This comment is based on what I've learned from watching Mine Rescue with Freddie and Juan.

Having just one type of screen/riffle/pads through your entire sluice is a ticket for losing gold.

Try sectioning your sluice into two to three areas, using different combinations of matting/miner's moss/punch plates/screens/expanded metal. Googling this program, and watching a few episodes where they modify sluices would benefit you a lot, giving you a better idea of how to set up your sluice for maximum recovery.

 

[Phil]

That is an impressive clean out for only four hours on a highbanker.

Time to buy a wash plant and excavator!

 

[Assembler]

That is an impressive clean out for only four hours on a highbanker.

Time to buy a wash plant and excavator!

A claim is needed first. Nice line of thinking though........

A longer sluice may not need to be cleaned out as often.

 

[John-Edmonton]

This comment is based on what I've learned from watching Mine Rescue with Freddie and Juan.

Having just one type of screen/riffle/pads through your entire sluice is a ticket for losing gold.

Try sectioning your sluice into two to three areas, using different combinations of matting/miner's moss/punch plates/screens/expanded metal. Googling this program, and watching a few episodes where they modify sluices would benefit you a lot, giving you a better idea of how to set up your sluice for maximum recovery.

It has a section in the hopper - mesh over miner's moss over "V" matting which catches at least half the flour gold before it reaches the lower sluice. I panned my tailings......about 3 fly-poops got away.

 

[John-Edmonton]

I made a video over the weekend on the Wedgy.