Thank you and thanks for watching. I do hundreds of tests like these to try and find the best ways to catch gold. I thought that others may be interested in them as well.
Mark Ayers Hi Mark. Thanks for watching. I'm glad it helps. Fluid beds work in the same way. They create a quicksand effect that traps the heavier material at the bottom.
Thank you Wilma and thanks for watching. I have several more of these test videos I’m currently working on and I’ll put them up here if you are interested.
Using your basic design I built one just under 5'8" long, inner measurement between the sides is 11 inches. 3/4" gap between each riffle, and each riffle 3/4" tall. with the undercut. Many layers of lacquer. Works great.
Hi Glen and thanks for watching. Congratulations on your build. That one should work very well for you. This design has been around for at least 150 years and probably longer for a reason. It catches gold better than anything I have found.
I've been watching a lot of videos studying different notions for holding the gold while clearing the cells of blonds, stones and most of the black sand. I'm playing with the water flow, depth and angle of a plastic 40" La Trap drop riffle, high banker - I'm glad I found your channel.
Thanks Brick, and thank for stopping by. I find it interesting watching these work as well. I may take this one out in the stream sometime and see if I can see if I'm catching the gold or not. :-)
Hi David and thanks for watching. I do many of these type tests and video them so I can see how gold reacts to different design changes, riffles, mats, etc. they help me build much more efficient pieces of equipment.
I like your videos. I would try making some of them but I am the type person that need plans. When I try making something from scratch I go through a lot of wood. Thank you for your works.
Big Country Vet Hi Big Country and thanks for watching. Yea, I hear you for sure. I usually make about 3 generations before I'm happy. Sometimes more. I only use the cheapest of wood on my projects to keep the costs down. If you want to try building some of my projects I have some how to build videos that may help.
Prolly the most fascinating video I have ever watched re sluices. Shame it weren't longer. If only I wern;t such a lazy ##### and made one of these and altered the riffles and noted the different reactions. Thanks for wonderful video
Mohammed Novalija Thank you Mohammed. This was a video I made to try and find the best Riffle shape. It was a bit short just to quickly see which direction I needed to go. It helped me make a very fine gold Sluice which is catching gold down to -100 easily. I'm working on some other projects right now but I will be making another one with some different Riffle shapes to see how they work in comparison and I hope to have the fine gold version up as well. Too many projects and too little time. 😄 Thanks for watching
Thanks Chuck and thanks for watching. After 50 years of trying about everything on the market, I have found that the drop riffle sluice is still one of the best and they are still my favorite. I still put in a lot of time testing different riffle designs and it's interesting how little changes can make a big difference.
That was so informative and well put together. Also a great design that has answered numerous questions speaking as someone newly interested in gold and gem prospecting. I'm UK based, we don't have an awful lot above bedrock I believe so the optimum design, all the better. I am so impressed and grateful for your research and design, and presentation I am bothering to write even though I'm having to use mouse on my (cracked screen) smartphone. One click at a time. Thank you for uploading this. Genius. Ps. It might be nice to be able to slide the perspex glass out along the length of the sluice incrementally for rinsing out the paydirt. Thanks again, awesome. Love your 'king of the hill' (lite) accent too. Thumbs up
Hi Spinny and thank you for taking the time and effort to watch and comment. I am finding that these sluices are some of the best I have tried over the past 50 years and I continue to modify and test them constantly. I’m right now in the process of making a new one with some of the changes that worked for me. So stay tuned. Yea, I wish it was easy to slide the glass along myself but it is very hard to seal that from leaking. I hope the new video will be more informative and easier to see the action. You might try making a small version of one of these and set it up as a recirculating system. I am finding that most of the gold isn’t found in the streams but in the dirt all around us. So take samples of everything around you and see what you come up with. You may be surprised. I was. Yea, We Utah’ns have kind of a different accent although it doesn’t seem like it to us. LOL.
@@utahavalanch thanks for your reply. I will definitely keep tuning in. I appreciate your innovation. And thanks for that final tip. I will try for sure. Happy panning.
Great video buddy, I like the plexiglass side, you can really see how it's functioning. One of the things I like about the goldhog mats is there isn't areas for the larger material to be engaged, and clog up the system. Thanks again for sharing!
Hey, Utah. Bout time for you to be heading back up the canyon with this good weather isn't it? Getting cabin fever here and need some new videos. You see what I'm down to for entertainment around here. :-) Yippers the GH mats are pretty nice. I wish I could get my GH out of storage and give it a good work out. But guess I'll have to wait for spring. :-(
utahavalanch Ask and you shall receive. Uploading one right now. It's from late December, running the grizzly gold trap. Been super busy and small injury (bruised ribs) had keep me off the river. For most of January. But going to hit it hard now that I'm feeling better.
Thank you kindly. I knew I could count on you. Sorry to hear about the injury. Those ribs can really hurt. Sure am missing summer right now. :-) I'm working the bugs out of a new indoor apartment sized prospecting set up and hoping that will help with the winter blues. :-)
Another Great creative mind at work. And, a great video showing just how the drop riffle works. I too love to dabble a bit. Keep up the Great work Sir.
Hi GreenMountain. Sorry so slow. RUclips didn't notify me of your comment. Thank you. I build 2 or 3 of these projects a week to see how things really work. I especially like the drop riffles because they are so efficient at catching the gold and there are many ways to modify them to change their behavior. Thanks for watching.
Your are more than welcome, I enjoyed it very much, as I also have a drop riffle that is now just sitting here. I loved it very much but, I have something new I am using that allows me to process large amounts of materiel quickly. Take a look if you care to see it. Keep up the Great work in your builds. It's great working in the shop. P.S. no worries on the not so slow reply. RUclips has been strange lately.
Hi Deplorable thank you and thanks for stopping by. I generally classify to around 4 classifications and run each classification separately and adjust the water flow for each one. Doing that and running small batches in a recirculating system where I can fine tune the sluice, I am getting way more gold than I ever did by running the big sluices in the streams because now I'm getting about 95 -98 percent of the gold instead of only 20.
Hi Doublenot and thanks for watching. I just threw this together quickly to run the tests but I'm finding it's been handy to watch what effect changing the water flow and angles makes on the material and I can see how it's catching gold. I'm in the process of making a little nicer one and keeping the clear side as well.
randy scottie toney Thank you Randy and thanks for watching. I have a new design I have been working with for a year now that is my all time favorite that you might be interested in. It's a little more involved to build but not much. It's a 2 part video and I'm working on the second part. A sneak preview is in my Urban Prospecting video. These are going to be my permanent Miller Tables I think.
hello again,,i like your drop riffles,,you must need a control pump,,how do they work in the creak,also did you experience with the under flow ,,am just curious..have good day my friend and keep them coming..thank you
Hi Lou and thanks for watching. Yes, with these recirculating sluices you need a pump. However if you watched my other videos on how to build a drop riffle sluice, you will see one that was designed for running in a stream or river and that is what I use when I am out working in the streams. They are especially good at catching the very small gold we have here. The under flow sluice is a good sluice and works very well.
Hi again Lou. Maybe this will help Drop Riffle Sluice Videos Part 1 ruclips.net/video/LJHBAAqrAbA/видео.html Part 2 ruclips.net/video/JX17HbgD6U0/видео.html
Hi Connie and thanks for watching. These are really quite simple to make. The riffles are square dowels you can buy at your local Home Depot store along with the rest of the lumber. I'm trying to get a couple of videos out on how to make these and some of the other simple sluices. Homemade sluices work every bit as well and in many cases better than the commercial ones.
I appreciate this vid so much... thanks for posting this. As a noobie to prospecting... you really have given me so much I never even thought about. In your opinion... is this the best design you've come up with for good riffle dynamics?... thank you for any response.
Hi Shane. Thank you and thanks for watching. No, this is just one of many hundreds of tests I’ve done. I thought that it was an interesting one that others would like to see. I think that a better design has the walls of the riffles straight up and down instead of being cut at an angle. I have been testing some new riffles this past 2 weeks that part of them didn’t work so well but another part worked far better than I had expected. I’m trying to build a new sluice now to try and duplicate the very good part. I’ll put up a video of it if I can get it to work again. Small changes in these can make a big difference in how they work.
@@americaswildestprospector Thank you and thanks for watching. I thought maybe this would be of some interest to some folks I do hundreds of these tests with different mats, riffles, to see how gold reacts with each type in order to find the best methods of catching that elusive gold.
Thank you Yaj and thanks for watching. This sluice has been very handy for testing new mats and riffles. I’m currently testing a new riffle design with it. If it works well, I’ll make a video.
Thank You for watching Tom. I have some more videos coming that I hope will be of interest to you. I'm doing some more drop riffle sluice testing here shortly.
Im loving all your video's. Im thinking of building a mini drop sluice out of some plexiglass i have around just so i can watch what's happening from all sides. My curiosity is could a drop riffle sluice be run with deep riffles and low water flow and on the underside a vibration from like an out of balance angle grinder or something be used to keep the sands bouncing. Would the black sands and heavy stuff continue to build up and force the blonds up to the slower water and out? If it does continue to build up and classify itself could some small holes be opened underneath and let a small amount of the heavy sand out into a collection? its all very interesting.
Hi and thanks for watching. Yes, you can build a plexiglass drop riffle sluice with deep riffles and low water flow. Mine are at least 3/4" deep and I screen all of my material down to about 4 sizes and adjust the water flow for each mesh size. Vibration on the underside will not keep the sands bouncing up and down in order to clean out the lighter material. The water flow moving across the top of the riffle creates a suction that is trying to suck the sand out of the riffle and that's why they dance up and down and bounce the lighter material up into the main water stream. The faster the water flow, the more suction. You will remove the gold with too much water flow and blow it out of the sluice. The best way to remove the black sands is to remove them before you start feeding the material into the sluice. If you don't then the best way is to run a black sand magnet over the riffles to remove the black sand out of them. Hope this helps.
@@utahavalanch thanks for the reply and helpful advice. I think your right about the vibrations not working like im thinking. The picture in my head is much like when you shake a gold pan all the heavy small material migrates down. If i could duplicate that movement mechanically and introduce material and water to the back side of the pan would the gold sand on the underside keep building up while the top of the pan over flows out the front? I guess it would be much like your fluid bed... without the spray water coming up from underneath. That fluid state of the shaking pan while a tiny bit is taken out the bottom and a small amount migrating out the front and out would it keep a happy continuous liquid sorting going on?
@@builtrodewreckedit If the water flow is adjusted right, the troughs in the sluice act just like a fluid bed. It is the same as shaking the gold pan to stratify the material down into the corner of the pan. The dancing sands are quick sand and anything that is heavier than they are will immediately drop to the bottom of the trough and stay there. They will eventually clean out all of a certain size material that the water flow can pull out. If the water flow is too high then everything will get cleaned out. That's why it's important to fine tune the water flow. So just the normal use of this will do everything you are wanting it to do.
Thank you for watching Amy. This is what I do most days. Just build and test a lot of different pieces of equipment to see how they work. Very interesting to me.
What about some groves put in drop riffle congruent with water flow at an 1/8 of an inch to undercut the larger Stone and dislodge them as it pushes up? The depth would be key. But it may be the solution to non classified mats. It may inundate the larger stones as vibrating does ? Excellent design sir. Your definitely spot on.
Hi Richard and thanks for watching. Yes, you could try that and it would work but unfortunately the problem is, that the force of the water running through the small grooves has quite a bit of force and when it hits the rock it sprays out in all directions and one of them is down. The force can easily blow out the fine black sand and gold. This type of Drop Riffle works best with material screened to about 12 mesh and smaller. Most all of the gold I work with is very tiny so this type of riffle works very well for me. Other manufacturers have come up with mats that are wide and shallow like the Keene Miracle mat so that there is much more room for the larger rocks to rest without disturbing the fine gold. However with that design, you have to watch the water flow very carefully as it can blow out the fine gold very easily. I have found that to get the most gold, I screen all of my material down into about 4 different sizes and run each one separately but I know a lot of people don't like to do that. I have run most all of the mats on the market at one time or another and I have found that it's best to run all the larger rocks and smaller sand in different runs so that you can adjust the water flow for each one of them.
Thanks Alan. I'm really liking your projects as well. Great ideas. Keep them coming. I made 6 fine gold recovery sluices and tested them this summer and believe it or not the Drop Riffle worked the best out of all the different mats and has the least amount of losses. I am currently recovering -100 to +200 gold from Alaskan Nome Beach black sand, Washington Beach black sand and Lake Michigan black sand. I have been thinking of a Drop Riffle High Banker for some time and it is a challenge for sure. However some of your latest builds have given me some ideas and I am currently working on a couple of prototypes. So I guess we'll see what we come up with over the winter.
Hi Mike and thanks for watching. About 17 years ago I started doing hundreds of tests like this to see how gold reacts to different design changes in equipment. Turns out very minor changes can make a big difference in how gold reacts. These drop riffles have been around for 200 years and I think they are still the best for catching the fine gold we have. But minor changes in them can make a difference in how well they work and rigs like this help me find the best designs.
Jeffrey Spradley You're welcome Jeff. Thanks for watching. If this is of interest, I have a new one I'm working on right now that I hope I'll be able to put up in the next little while.
It's AMAZES me others NEVER do these sorts of tests. I'd verify design w LEAD, too: Comparing input vs recovery to verify angles vs water volume & lengths How else can they ensure that considerable amounts of Au aren't lost..? I'd hire a hydrologist & fluid mechanical engineer for theory before optimizing & verifying design w lead.
Hi Truman and thanks for watching. I build and test many different pieces of prospecting equipment. This is just one of many tests I do on all of them and I thought some folks might be interested in it. This is my medium size gold test where I use a variety of different sizes of lead and gold. I do tests changing the water flow and angle of the sluice. Then I will run the tests all over again with very fine gold to see how it reacts with this design. At the end of each run I very carefully pan the tailings to see if there are any losses. Thus I can fine tune the design to run at its highest efficiency. I can swap out the riffles for different shape and I sized ones. I also do these tests with all the different sluice mats I’m interested in and I can make different designed mats no one else makes and test them. I take videos on each run so I can watch the action more closely over and over. This helps me go back later on to refresh my memory on how well a certain design worked. These tests have really been helpful to me to see how different sizes of gold react to different design changes so I can build more efficient equipment. Sometimes a small change can make a very large effect on how gold is caught.
In this great video, what was the mesh you classified to? -20? and what was the water gph or speed? what is the Angle you cut the bottom part of the riffles?
Robert T Burrows Hi Robert and thanks for watching. The classification is about -12 /+20 mesh. I usually classify and run this first for the larger gold. Then I classify the tailings to -30, -40 and run each separately at a reduced water flow for each classification.. I'm running a 264 GPH pump with a valve on a 6" sluice. The angle was cut at 30 degrees. I found it's best to have the Riffle face that the sand hits as it goes into the trough to be straight up and down without the angle cut. The rounded nose on the slick plate where it runs into the first trough turned out to be a big "must have" as the gold follows it right down into the trough guaranteeing it ends up getting caught. I am currently working on 3 more different Riffle shapes and a little different drop Riffle sluice and I'll see if they work out well enough to put up. It's interesting that I found if you drop the water flow way down, you can run the sludge material and easily catch the -100 gold better than with the mat sluices. The troughs on these are big enough to hold the gold and black sand which I process to get more gold.
@@utahavalanch Thanks for the reply. Im an absolute believer in drop riffle boxes of any sorts. Most of our material running is onsite so we use wider longer boxes. I like the Angle of the second riffle as it tosses the heavies back and releases the lighter material to flow. Agreed on that Rounded nose as it shoves the heavies str8 down before they can float out. Id like to see a video of a longer sluice run showing all riffles working.
Robert T Burrows I have pretty much given up stream sluicing and my big Gold Hog sluices for these as a recirculator because I can control everything so much better and get more gold. I'll try to include more of the other riffles in my next video. I usually keep all the gold in the first 2 riffles to make for less cons to process and so I usually don't pay much attention to the rest of them unless I get any gold in the tailings. I am currently using a 10x22" sluice with 3/4" deep troughs and they hold about 2oz. of material each which doesn't take long to run on the Miller Table. I'll see if I can make a longer sluice. What size and Riffle depth do you like?
If you ever make another (great) video like this ... maybe you can use food coloring to make it easier to see the little currents coupled with even the slowmo you can get off an iPhone ... bc this is excellent info.
Hi Spike and thanks for watching. Yea, I know what you mean, I tried doing those with a silicone mold for a mat. I make a lot of different molds for mats and the molds don’t always produce how you think they will.
@@spikechampkart55 Yippers, it’s good stuff alright. I thought about getting into it a few years back but it was too expensive. Good for mass production but I test different designs and concepts and so I make 30 - 40 different pieces of equipment a year for testing and so it wouldn’t work out for me. I wish there was a way to do it cheaply for one offs.
you could add a kind of mesh, but not mesh, er say a line of straight wire to lift the larger stones what would slide over but the smaller particles still drop through into the dropriffle. That way your first few dropriffles are dedicated to the finest gold capture and you can adjust the shape of the later dropriffles allowing more agitation to remove the larger pebbles?
Geoff C Hi Geoff, and thanks for watching. Yes you could do that. However I have found that it's easier to just screen the material down to a smaller size before running it and then pan out the larger size material. Some manufacturers make wide troughs about 1-1/2" wide to make enough room for the larger material as well as the small. Lots of ways to do it.
Hi Addestensfors and thanks for watching. Yes, the LeTrap sluices are very good gold catchers. The lower edge of the drop riffle is elevated a bit making it similar to these drop riffles. There are other similar types that have the bottom edge of the riffle lower and flatter much like on stairs that don’t work as quite as well and the gold catching area is much smaller. However if you keep the sluice angle flatter and the water flow slower, they will work quite well. I’m speaking of finer gold that I work with. With larger gold of course, you can have a steeper sluice angle and water flow. I prefer the deeper drop riffles like in the video as they have much deeper pockets in which to store the heavies and less chance to lose much gold. I can easily sort the gold and black sand at home on my Miller Table rather than try to do it with my sluice.
Zion Gray Hi Zion and thanks for watching. Yes it could but it's not necessary as they clean themselves out automatically. The sands are bouncing up and down and the lighter ones are getting thrown out when they bounce high enough to get caught in the water current and only the heaviest material like gold and black sands will remain in the trough. So you can keep feeding material into the sluice and it will get rid of the garbage automatically. That's why this is one of the best sluice designs around and has been for over 150 years.
utahavalanch it would be cool to make a way to lift up the riffles all at once while running ( if they where cubic aluminum held down like the river sluices latch system. With a flush rubber mat glued to the bottom of the box that doesnt move but acts to make the riffles water tight so nothing creeps beneith and out.) But to release the cons it into a catch tray or bucket say if it was a highbanker type. Just to make clean up n con collection faster.....i was thinking your design would be cool in aluminum but a little bit wider and longer.....i wanna try a drop riffle system. Do you know if they are better then raised riffle as in faster feeding and better collection?...to me it reminds me of a japanese design i love the look of it its almost id say art. Great job on the build and knowledge of this type of sluice
utahavalanch sorry another question...would it get less clogged up and speed up the natural drop and cleanout method if on the ends of each drop riffle it where to have a small flat extended lip or even a small raised riffle either to both tumble it faster and keep it from being level so the. Gold dont roll over amd out?
@@ziongray918 This is much easier to clean out than having removable riffles. You just turn the sluice on it's side so that the bottom and the side forms a V and then just take a can or water bottle and wash the grooves down into the bottom of the V and out the sluice. Raised riffles are good for course gold and unclassified material but they lose the fine gold. Drop riffles are very good on the fine gold but they need to have the material classified.
@@ziongray918 The design on this is about the best I have discovered in 10 years of building and experimenting. It's a very simple design and it works very well as long as you don't over do the water flow. So if you want to build one that is simple and works very well, this design is it.
Have you run this system with straight edges to your riffles rather than undercutting them ? - and have you tried making the width of the riffles much narrower ? - at least a quarter narrower than the gap between riffles ?
Hi Mohammad and thank you for watching. Yes, I have tried the straight edges on the riffles and they work much better. Also the gap or trough between the riffles works the best if it is 3/4 inches wide. 1/2 inch doesn’t let the material work and get rid of the lighter material like it should. 1/4 inch doesn’t hardly work at all and will fill up with black sand very quickly and it won’t leave any room for the gold. Also the deck should be 3/4 inches thick by about 7 to 9 inches long. The riffles work best if they are about 5/8 inches high and 1-1/4 to 1-1/2 inches wide.
@@utahavalanch I am currently running square riffles 1/8th high and 1/8th long with the gap 3/8 wide. The gold in my area is never 3/8ths size. It seems to run okay catching 95% of the gold and accumulates not too much cons , but does need to be cleaned out often , which I do not mind as it only takes a minute or so , and I LOVE seeing gold often rather than digging for an hour like many prefer.
@@mohammednovalija That will work well for you as long as you clean out often like you say. I made some silicone mats similar to yours that have riffles that are 3/16” high x 1/8” wide and 1/8” wide troughs. They are good for small runs of 1/2 - 3/4 gallons of cons or test samples. I do a lot of urban prospecting and collect 1/2 gallon samples of dirt I run across and these mats work well for that. But if I have to run more than a gallon, I use the big riffle/trough sluices.
Thank you AU Miner and thanks for watching. I do a lot of testing of different types of equipment and mats to try and understand what catches gold the best. I am currently working on several more videos of these hard riffle sluices if you are interested.
@@utahavalanch Def interested :) I think a drop riffle is far superior to a raised riffle. I've been designing and testing some of my own. I'm pondering a series of small to large drop cuts, to capture the fines and the large without classification. Very small 1/8" deep cuts, then increasing in size. My hope is the small riffle will catch the small gold and the largers gold will be caught by the nest appropriate size riffle.
@@AUMINER1 After 12 years of testing, I’ve found that the drop riffle is the best at catching gold. I primarily work with very fine gold and I have found that these large deep riffles work the best for the fine gold. The large troughs have plenty of room to catch all the heavies and I can separate the gold out of the concentrates very easily with my Miller Table or gold pan. However the riffles work best with classification. As you can see in the video, when I run -4 mesh material through the sluice, the larger rocks fill the riffles and shut the material exchange down and the gold has no where to go but out the end of the sluice.
@@utahavalanch Just tonight I was running my 60- cons through my latest test riffles. I was shocked to see a line of mirco gold in ta riffle test designs. Basically a small riffle before/on top of a larger riffle. The rest of the other riffles without that design had nothing. I reran the test with just dirty water, and a line of 500mesh blond sand was caught in the same place, and the rest of the riffles were 100% clean. I might be on to something :)
To process about 700 kilograms per hour. What dimension should your design be approximately in terms of the length and width of your lock design and what height of rifles. ??
Hi Carlos. I have a gentleman down in Africa that is building one to try and handle that much material. His is 20” (50cm) wide x about 12’ (365 cm) long. That would still be pushing a sluice that size. You may need 2 of them side by side. It would be best if you could screen your material through an 8 mesh screen to keep from losing the fine gold.
Hi Andrew, and thanks for watching. I and at least 3 others have done the tests. I haven’t been able to get my video out yet. They all come to the same conclusion. Basically big gold goes to the bottom rather quickly but when it comes to small gold, 20 or 30 mesh and smaller That is a different story. Most fine gold is lighter than most anything else in the pan and won’t sink to the bottom unless there is only a very thin layer of dirt in the pan. If you classify the dirt so all material is the same size, then you will have better success but usually the black sand will be heavier and the gold will mix in with it because it has been smashed flatter and will be lighter. That is why it’s so hard to separate the fine gold from the black sand. Hard rock university has some of the best videos on how to pan micro gold. One of the best videos demonstrating stratification is the RUclips video….. “Does gold sink in a gold pan” by Allan Dampier He also sells one of the best fine gold pans. Allan does a good job of demonstrating how gold stratifies. Also pay close attention to his method of panning. He only works a small amount of material at a time and he keeps the material moving from side to side and always under water. This side to side motion keeps the gold at the same level in the riffles. It also keeps the material fluid and allows the gold to continue to settle deeper into the riffle and let the lighter material move out of the riffle. There is no motion to try and “Throw it out of the pan” like traditional panning. Just raise the back of the pan slightly and the lighter material will float out so the gold tends to stay in the riffle. I only work with 40 mesh gold down to about 500 mesh. I use Allan’s panning technique to pan and then use Keith’s method of tapping to collect the invisible to the eye gold in one spot so you can see it to collect it. You would be surprised at how much gold you can find in the micro range.
Anagram Confirmed Hi Anagram and thanks for watching. You're right. Those are some test pieces that are about 12 mesh. After I shot this video I ran a gallon of 30 mesh material and caught 1 gram of it. I didn't find any in the tailings. If you reduce the water flow to match the size material you are running you can catch down to -100 gold quite easily. The thing is with this type of sluice is that there is enough room for the gold and black sand both. I keep all black sand and process it separately and recover about a gram of gold per quart of it. The curved nose of the slick plate guides the gold down into the trough and once there it sinks to the bottom and it's very hard for it to get out.
I'm not very good at the metric system :-) but I'll give it a try. The space between the riffles is 3/4 inch or 1.90 cm or 19.05 mm if my conversion program is working. The height of the riffles is the same. You can also make the riffle height 5/8 inch, 1.5 cm 16 mm if you would like but keep the distance between riffles 1.9 cm. To make sure I get all the gold, I like to have enough room in the riffles to catch all the black sand as well as the gold. If you lose any black sand, you will lose the gold that is the same weight. I like to catch it all and then separate it on my Miller Table.
Hi Models and thanks for watching. It’s not too bad once you get the hang of it. You just tip it to the side and let the excess water run down the side rail and out the end of the sluice. Then you can then use a squirt bottle or something to wash each of the grooves out. I like that you can clean each groove individually and check to see how far down the sluice gold has travelled so you can adjust your water flow. You have to watch the grooves closely as they tend to hang on to the gold and you may have to pick it out with tweezers.
I think you mis-analyzed the efficiency of your riffles here. The very first spoonful of concentrate filled up the riffles that had the 45 degree cut backward, and what settled there never moved again nor did it have the dancing effect you want. It did create a nice 45 degree of concentrate forward towards the next riffle and that worked fine. But again, if the first spoonful of concentrate never moves then the function of the riffle cut backward is lost. I believe the simple right angle plain ol' straight riffle would work better but you didn't show it here. Also, these high pieces of wood riffles which is the very thing that makes it effective to catch tiniest mesh pieces are what catches the big rocks also and which makes the project totally ineffective. Ultimately, not a good choice unless, as you suggest, the material must be classified down to very small particulate. Of course, I just rehashed what you said, ha. I'd prefer the hands-on pan classifier with different screens down to 1/4 inch, throw it all into a take-home bucket and have a play-date at home some Saturday/Sunday afternoon. Love your vids. ciao.
Hi Trumpsahead, This test was mainly for those who say that it’s best to cut an angle on the riffle. The first riffle was a flat cut with a slight toe cut out at the bottom to see if any of the fine gold would settle down there. As you can see the 45 deg cut creates a little different current. The flat cut creates a vortex that helps clean out the lighter material better. If you look at the material up against the glass, you’re right it doesn’t move as there is a dead zone there. However over towards the middle you can see it is exchanging out like it should. Even though the trough looks full the water current moving through the sand turns it into a quicksand and anything heavy like gold will fall through to the bottom and stay there protected by the sand above it. Having deeper than normal troughs means that the water flow at the bottom is greatly reduced over that at the top and so It’s very hard to blow the gold out of there once it hits bottom. Gold separation depends on weight. If all the material is the same size, gold will always sink to the bottom. So I always classify. If you have 30 mesh gold and 1/4” or 1/8” rocks and you have to set the water flow to clear out the larger rocks, the gold will go as well. If everything is classified to the same size, the rocks will get washed out before the gold. In my testing, I don’t care what gets caught by the sluice. I only care about what gets lost so I always run the tailings through the miller table to see if there are any losses. With this video I ran a gallon bucket of 20 mesh sand and 1-1/2 grams of 30 mesh gold through 4 times at different water flows and the sluice caught every piece each time. Most in the first trough with 2 or 3 in the second. These sluices actually make a very good finishing sluice as there is plenty of room to catch the black sand and the gold unlike the mats which fill up with black sand very quickly and leave very little room for the gold to settle in. Thanks for the comment.
FlyfishermanMike Hi Mike, that it is. I video dozens of runs and then analyze them at all different speeds to try and find the best configurations for my sluices. Thanks for watching.
@@utahavalanch I have some questions, anyway I could get in touch with you through e-mail, if you're not too busy? I'm taking some scouts camping up AF canyon to pan and I'd like to increase our chances as much at possible. I'm looking for a for spot to pan with a place to camp nearby. Thanks!
Hi Mike, I would be glad to help you the best I can. If you could leave me an eMail address I can contact you at I can get in touch with you and erase your email addy from here. Good area to pan in.
Hi Antonio and thanks for watching. I'm sorry but I don't right now as I have so many other things going on that I have to take care of so I hate to take on more and not be able to get them out in a reasonable time. I have a lot of requests for these and so that's why I do the "How to Build" videos on them so that folks can try to try their hand at building them. They are a pretty simple design and quite easy to build.
Hi and thanks for watching. I don’t recall seeing any but someone may have tried them. I think if they worked well you would see more of them. I have square riffle mats with the top edges rounded off a bit that work very well.
@@utahavalanch it gives you the round top edge and a back cut. I have a lot of 1" and smaller bamboo. I'm just throwing out a hypothisis. What if you had say a .75" dowel shape riffle, on top of a vmat or carpet, then have a smaller say 3/8 by 1/4 ridge say a half to 2 inches in front of it.... with a gap, then repeat. I'm thinking if you have the material, you could make them fit tight and run any mat under then have then wedge in tight --- to me a combination off wood that is removable over whatever mat makes sense but I have no real experience. I also have a lot of mexican palm fronds and the stems are very strong and you can cust some interesting profiles. My thinking is that having riffles have range or shpes, sizes and patterns makes sense. I'm also thinking of having something in the 4-6 foot range. The idea I am working on is to run successive sluices 2-4 maybe that get wider and less slope as they go and have smaller and smaller grizley bars. I'm also dreaming of setting something up where you could load good amounts of material and walk away. My goal is a combination of wanting to separate out useful sizes of gravel and sand from such that are mixed in with a lot of soil. The gravel was originally from the large flat roof. There is also DG under the gravel/soil mix that I may remove some or all. Have you heard of DG having gold?
@@1FeistyKittyI’m not sure how it would work right off. The thing to do would be to build a prototype like I have here with a clear side and give it a try. I do this so I can watch how the dirt and gold reacts inside the riffles. I video tape a run or two so I can watch it over and over. I have a gram of fine gold I use in about 1/2 gallon of sand that I use to test with and that way I can check the tailings to see if there are any losses and also see where in the sluice gold collects. Try building a basic sluice that can be easily modified and experiment with different ideas that you come up with. You may be surprised at how gold reacts to different designs. I don’t know about the DG gold but I do a lot of urban prospecting and I have found gold in some of the most unusual places. You’d be surprised at how much gold collects on streets, large parking lots, gutters, etc. I take a shop vac to big parking lots and roads and collect quite a bit of very fine gold.
Hi and thanks for watching. I usually set a starting point angle of about 10 degrees and then adjust it from there if I need to. If it’s fine gold material, I may set it closer to 7 or 8 degrees to give the fine gold a chance to settle.
Too many flat spots. Needs more riffles. Small V- grooves in those flat spots will improve catching the fines. It's too easy to clog up those big riffles with minimal water pressure..
Yes, many changes can be made to these. I have one that has large circles in the riffles as well that catches the fine gold. I have also tried the grooves on those flat spots. However if these sluices are run properly they only need about 3 or 4 riffles. My big one I ran all last season didn't ever get a piece of gold beyond the 2nd riffle. The version I'm working with now, only needs 1 or 2 riffles as 80% of the gold is caught on the slick plate and any that move on down are funneled into the first riffle where they stay. Yes, like all sluices you have to run them properly or they don't work well. I'd say that about 80% I see on the internet fall in that category. Thanks for watching.
Yippers, this isn’t paydirt. If it was it would be too dirty to see anything. This is one of my many test set ups. I have buckets of cleaned sand of all sizes I use for these tests so I can shoot video of what is going on in the sluice. That way I can watch it over and over, and speed it up or slow it down. I use 2 grams of gold in sizes from -100 up to about 10 mesh so I can see what the different sizes do at different classifications of sand and water flow. I change the water flow and pan out each riffle separately so I can see where each gold size settles. Then I change the size makeup of the sand and start again. All you can see in this run is the larger sizes but there is 1-1/2 grams of fine gold in there as well. I pan the tailings 2 tablespoons at a time to check for any losses. This is just 1 of 12 runs I did on these riffles and then I used the information I got from these tests to modify them and make different ones. Then I started again. I do this on all of my mats as well so that when I run paydirt through a sluice, I know exactly how to set it up to catch all the gold.
Jim Murphy Hi Jim, thanks for watching. Actually this is basically the same design I used over 50 years ago with my long tom. Over the years I have learned to move the riffles closer together and instead of the gaps being 12" apart they are now 3/4". This is my condensed version of my old 12 footer. This one is much easier to carry 😝 My buckets have also shrunk down to 2 gallon. Love progress. 😄 but I can't fry my eggs in these new plastic gold pans. 😢
As far as active exchange & physics are concerned. This test confirms that over burdening quickly & a large portion of the collection areas are in complete stall & ineffective. Almost the perfect bad example. Sorry for my brutal honesty.
Actually up until the -4 material was added, it was working just the way it should. The water passing over the trough creates a suction that tries to draw the sand out. The dancing sands create a quicksand that allows the gold and heavier material to drop down through to the bottom where it is protected. When the water slows or stops the sand collapses and the gold is locked into place. Just like in a crevice on bedrock in a stream. This design is over 150 years old and still has a number of companies making these today. This design wouldn't still be around and popular if it didn't work well for a lot of people. I have been using this design in different forms for 50 years and I'm still using it and I still find it one of the best. I ran a bucket of -30 cons through this after shooting the video and it caught every piece in the top 3 riffles. I Miller Table all of my tailings to be sure.
like to see this made but in metal and with hydraulic flow. would be neat to see the hydraulic riffle action in this type of drop style model and the difference it is compared to this with the large raised riffle spaced out. love these science project style tests feels like my brains downloading some complex quantitative information.
Hi and thanks for watching. Well, maybe someone with metal working equipment will try and make something like that one of these days. I make many of these type projects to see how the gold reacts to different designs. So I work primarily with wood to keep costs down. These tests help me design more efficient pieces of equipment to catch the gold. It’s quite interesting that minor changes in a design can have a large impact on how the gold reacts.
That was an excellent piece of research and development. Thank you for sharing your knowledge and for taking the time to make the video
Thank you and thanks for watching. I do hundreds of tests like these to try and find the best ways to catch gold. I thought that others may be interested in them as well.
This is the best video on the subject I have seen yet, by far. Thank you
Thank you Brandon and thanks for watching.
Thanks for the video. Very nicely done and great explanation of how the drop riffle sluice works. Keep it up.
Hi Ed, Thanks for watching. I have a couple more coming that I hope folks will find of interest.
Excellent explanation on how a sluice works. Now it makes sense to me. Thanks
Mark Ayers
Hi Mark. Thanks for watching. I'm glad it helps. Fluid beds work in the same way. They create a quicksand effect that traps the heavier material at the bottom.
Good job on presenting a visual on the need to classify and control water flow.
Artic Miner
Hi Artic Miner. Thank you and thanks for watching.
You've got it engineered to a science. Thanks for the excellent demo.
Thanks, Ruby. I'd like to see a video on how you made your Big Ruby sluice sometime. Nice job.
utahavalanch my sluice has a series of deep U channels that act as drop riffles. Similar to the demo I think that the flat side creates more vortices.
Excellent build and fascinating insight gained as a result! Keep experimenting.
Hi Matt and thanks for watching. I'm at this every day and have some interesting things I'm working on presently. Hope to get the videos out soon.
Thank u for ur valuable information no one else has ever explained it so well
Thank you Wilma and thanks for watching. I have several more of these test videos I’m currently working on and I’ll put them up here if you are interested.
I appreciated your style of teaching very very well done and you have increased my chances of finding gold imensly. Thank you very much
Scuba Steve
Thank you Steve and thanks for watching. Hope we will have some more that will be of interest.
Using your basic design I built one just under 5'8" long, inner measurement between the sides is 11 inches. 3/4" gap between each riffle, and each riffle 3/4" tall. with the undercut. Many layers of lacquer. Works great.
Hi Glen and thanks for watching. Congratulations on your build. That one should work very well for you. This design has been around for at least 150 years and probably longer for a reason. It catches gold better than anything I have found.
I've been watching a lot of videos studying different notions for holding the gold while clearing the cells of blonds, stones and most of the black sand. I'm playing with the water flow, depth and angle of a plastic 40" La Trap drop riffle, high banker -
I'm glad I found your channel.
@@imdawolfman2698
It’s good to do a lot of experimenting to find what works the best. Those Le Trap sluices are some nice ones. Good gold catchers.
@@utahavalanch Which design.??
@@CARLOSCESPEDESbiocihealth
Hi Carlos and thanks for watching. I decided to go with the straight up and down on both walls of the trough.
Thanks a lot for your time and dedication 4 this video! very clear information.
Jorge Chaves
Thank you Jorge and thank you for taking the time to watch.
Another great video ! Great view with the Plexiglas. It's cool to see how they work inside.
Thanks Brick, and thank for stopping by. I find it interesting watching these work as well. I may take this one out in the stream sometime and see if I can see if I'm catching the gold or not. :-)
Interesting video it’s nice to see it in action
Hi David and thanks for watching. I do many of these type tests and video them so I can see how gold reacts to different design changes, riffles, mats, etc. they help me build much more efficient pieces of equipment.
I like your videos. I would try making some of them but I am the type person that need plans. When I try making something from scratch I go through a lot of wood. Thank you for your works.
Big Country Vet
Hi Big Country and thanks for watching. Yea, I hear you for sure. I usually make about 3 generations before I'm happy. Sometimes more. I only use the cheapest of wood on my projects to keep the costs down. If you want to try building some of my projects I have some how to build videos that may help.
Prolly the most fascinating video I have ever watched re sluices.
Shame it weren't longer.
If only I wern;t such a lazy ##### and made one of these and altered the riffles and noted the different reactions.
Thanks for wonderful video
Mohammed Novalija
Thank you Mohammed. This was a video I made to try and find the best Riffle shape. It was a bit short just to quickly see which direction I needed to go.
It helped me make a very fine gold Sluice which is catching gold down to -100 easily. I'm working on some other projects right now but I will be making another one with some different Riffle shapes to see how they work in comparison and I hope to have the fine gold version up as well. Too many projects and too little time. 😄 Thanks for watching
Really great ideas for the sluice builder. Keep up the good work.
Thanks Chuck and thanks for watching. After 50 years of trying about everything on the market, I have found that the drop riffle sluice is still one of the best and they are still my favorite. I still put in a lot of time testing different riffle designs and it's interesting how little changes can make a big difference.
Great work there.You've made a very good explanation.Thank you for your time.
Hi Birdwing, thank you for watching.
Very interesting and thought provoking thanks!
Triplebacon Art
Thanks for watching. This is a very good design that has been around for a thousand years and still works very well today.
That was so informative and well put together. Also a great design that has answered numerous questions speaking as someone newly interested in gold and gem prospecting. I'm UK based, we don't have an awful lot above bedrock I believe so the optimum design, all the better.
I am so impressed and grateful for your research and design, and presentation I am bothering to write even though I'm having to use mouse on my (cracked screen) smartphone. One click at a time. Thank you for uploading this. Genius.
Ps. It might be nice to be able to slide the perspex glass out along the length of the sluice incrementally for rinsing out the paydirt.
Thanks again, awesome. Love your 'king of the hill' (lite) accent too. Thumbs up
Hi Spinny and thank you for taking the time and effort to watch and comment. I am finding that these sluices are some of the best I have tried over the past 50 years and I continue to modify and test them constantly. I’m right now in the process of making a new one with some of the changes that worked for me. So stay tuned.
Yea, I wish it was easy to slide the glass along myself but it is very hard to seal that from leaking. I hope the new video will be more informative and easier to see the action.
You might try making a small version of one of these and set it up as a recirculating system. I am finding that most of the gold isn’t found in the streams but in the dirt all around us. So take samples of everything around you and see what you come up with. You may be surprised. I was.
Yea, We Utah’ns have kind of a different accent although it doesn’t seem like it to us. LOL.
@@utahavalanch thanks for your reply. I will definitely keep tuning in. I appreciate your innovation. And thanks for that final tip. I will try for sure. Happy panning.
Great video buddy, I like the plexiglass side, you can really see how it's functioning. One of the things I like about the goldhog mats is there isn't areas for the larger material to be engaged, and clog up the system. Thanks again for sharing!
Hey, Utah. Bout time for you to be heading back up the canyon with this good weather isn't it? Getting cabin fever here and need some new videos. You see what I'm down to for entertainment around here. :-) Yippers the GH mats are pretty nice. I wish I could get my GH out of storage and give it a good work out. But guess I'll have to wait for spring. :-(
utahavalanch
Ask and you shall receive. Uploading one right now. It's from late December, running the grizzly gold trap. Been super busy and small injury (bruised ribs) had keep me off the river. For most of January. But going to hit it hard now that I'm feeling better.
Thank you kindly. I knew I could count on you. Sorry to hear about the injury. Those ribs can really hurt. Sure am missing summer right now. :-) I'm working the bugs out of a new indoor apartment sized prospecting set up and hoping that will help with the winter blues. :-)
Thank you for this excellent video!
@@lachezarslavov2327
Thank you and thanks for watching.
Another Great creative mind at work. And, a great video showing just how the drop riffle works. I too love to dabble a bit. Keep up the Great work Sir.
Hi GreenMountain. Sorry so slow. RUclips didn't notify me of your comment. Thank you. I build 2 or 3 of these projects a week to see how things really work. I especially like the drop riffles because they are so efficient at catching the gold and there are many ways to modify them to change their behavior. Thanks for watching.
Your are more than welcome, I enjoyed it very much, as I also have a drop riffle that is now just sitting here. I loved it very much but, I have something new I am using that allows me to process large amounts of materiel quickly. Take a look if you care to see it.
Keep up the Great work in your builds. It's great working in the shop.
P.S. no worries on the not so slow reply. RUclips has been strange lately.
One of the best demonstrations on how matting works and the importance of classifying.
How many groups should you classify to?
Hi Deplorable thank you and thanks for stopping by. I generally classify to around 4 classifications and run each classification separately and adjust the water flow for each one. Doing that and running small batches in a recirculating system where I can fine tune the sluice, I am getting way more gold than I ever did by running the big sluices in the streams because now I'm getting about 95 -98 percent of the gold instead of only 20.
@@utahavalanch Hey, thanks for the reply. I enjoy watching your videos.
@@hockeydad6211
Thank you for taking the time to watch them. Most appreciated.
Always love the videos. This is one of the best with good info.
Hi Doublenot and thanks for watching. I just threw this together quickly to run the tests but I'm finding it's been handy to watch what effect changing the water flow and angles makes on the material and I can see how it's catching gold. I'm in the process of making a little nicer one and keeping the clear side as well.
Diggin the sluice. Thank for posting your experiment. Will you say "damn it Bobby!"
nice video utah been watching your videos for 3 years now made 2 of your miller water tables thanks for the info
randy scottie toney
Thank you Randy and thanks for watching. I have a new design I have been working with for a year now that is my all time favorite that you might be interested in. It's a little more involved to build but not much. It's a 2 part video and I'm working on the second part. A sneak preview is in my Urban Prospecting video. These are going to be my permanent Miller Tables I think.
hello again,,i like your drop riffles,,you must need a control pump,,how do they work in the creak,also did you experience with the under flow ,,am just curious..have good day my friend and keep them coming..thank you
Hi Lou and thanks for watching. Yes, with these recirculating sluices you need a pump. However if you watched my other videos on how to build a drop riffle sluice, you will see one that was designed for running in a stream or river and that is what I use when I am out working in the streams. They are especially good at catching the very small gold we have here. The under flow sluice is a good sluice and works very well.
thank you so mutch,,i will look for the river sluice
Hi again Lou. Maybe this will help
Drop Riffle Sluice Videos
Part 1
ruclips.net/video/LJHBAAqrAbA/видео.html
Part 2
ruclips.net/video/JX17HbgD6U0/видео.html
Very nice I will have to try to make this one day. Thank you for sharing. ;)
Hi Connie and thanks for watching. These are really quite simple to make. The riffles are square dowels you can buy at your local Home Depot store along with the rest of the lumber. I'm trying to get a couple of videos out on how to make these and some of the other simple sluices. Homemade sluices work every bit as well and in many cases better than the commercial ones.
I appreciate this vid so much... thanks for posting this. As a noobie to prospecting... you really have given me so much I never even thought about. In your opinion... is this the best design you've come up with for good riffle dynamics?... thank you for any response.
Hi Shane. Thank you and thanks for watching. No, this is just one of many hundreds of tests I’ve done. I thought that it was an interesting one that others would like to see. I think that a better design has the walls of the riffles straight up and down instead of being cut at an angle. I have been testing some new riffles this past 2 weeks that part of them didn’t work so well but another part worked far better than I had expected. I’m trying to build a new sluice now to try and duplicate the very good part. I’ll put up a video of it if I can get it to work again. Small changes in these can make a big difference in how they work.
@@utahavalanch you have great content... thanks for showing us your projects. I'll check out your new vids as you post them. Thanks again.
Very nice experiment
@@americaswildestprospector
Thank you and thanks for watching. I thought maybe this would be of some interest to some folks I do hundreds of these tests with different mats, riffles, to see how gold reacts with each type in order to find the best methods of catching that elusive gold.
I love the design of your sluice
I am going to add to my sluice
❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️
Thank you Yaj and thanks for watching. This sluice has been very handy for testing new mats and riffles. I’m currently testing a new riffle design with it. If it works well, I’ll make a video.
@@utahavalanch
I love the header design also
No huge spray bars
Do you varithane the woods?
@@yajtramer6913 Yes, I use Helmsman spar varnish on it. About 4 to 6 coats.
@@utahavalanch
Looks awesome
Beautiful workmanship
@@yajtramer6913 Thank You.
Hello, very interesting. Gold seeker is also my hobby. Thank you have learned a lot what I can improve with me. Greetings Tom
Thank You for watching Tom. I have some more videos coming that I hope will be of interest to you. I'm doing some more drop riffle sluice testing here shortly.
Im loving all your video's. Im thinking of building a mini drop sluice out of some plexiglass i have around just so i can watch what's happening from all sides. My curiosity is could a drop riffle sluice be run with deep riffles and low water flow and on the underside a vibration from like an out of balance angle grinder or something be used to keep the sands bouncing. Would the black sands and heavy stuff continue to build up and force the blonds up to the slower water and out? If it does continue to build up and classify itself could some small holes be opened underneath and let a small amount of the heavy sand out into a collection? its all very interesting.
Hi and thanks for watching. Yes, you can build a plexiglass drop riffle sluice with deep riffles and low water flow. Mine are at least 3/4" deep and I screen all of my material down to about 4 sizes and adjust the water flow for each mesh size. Vibration on the underside will not keep the sands bouncing up and down in order to clean out the lighter material. The water flow moving across the top of the riffle creates a suction that is trying to suck the sand out of the riffle and that's why they dance up and down and bounce the lighter material up into the main water stream. The faster the water flow, the more suction. You will remove the gold with too much water flow and blow it out of the sluice. The best way to remove the black sands is to remove them before you start feeding the material into the sluice. If you don't then the best way is to run a black sand magnet over the riffles to remove the black sand out of them. Hope this helps.
@@utahavalanch thanks for the reply and helpful advice. I think your right about the vibrations not working like im thinking. The picture in my head is much like when you shake a gold pan all the heavy small material migrates down. If i could duplicate that movement mechanically and introduce material and water to the back side of the pan would the gold sand on the underside keep building up while the top of the pan over flows out the front? I guess it would be much like your fluid bed... without the spray water coming up from underneath. That fluid state of the shaking pan while a tiny bit is taken out the bottom and a small amount migrating out the front and out would it keep a happy continuous liquid sorting going on?
@@builtrodewreckedit
If the water flow is adjusted right, the troughs in the sluice act just like a fluid bed. It is the same as shaking the gold pan to stratify the material down into the corner of the pan. The dancing sands are quick sand and anything that is heavier than they are will immediately drop to the bottom of the trough and stay there. They will eventually clean out all of a certain size material that the water flow can pull out. If the water flow is too high then everything will get cleaned out. That's why it's important to fine tune the water flow. So just the normal use of this will do everything you are wanting it to do.
@@utahavalanch Thanks so much... I sure have fun thinking about this but you really are saving me alot of frustration.
Thank You for sharing this Valuable Information
Thank you for watching Amy. This is what I do most days. Just build and test a lot of different pieces of equipment to see how they work. Very interesting to me.
What about some groves put in drop riffle congruent with water flow at an 1/8 of an inch to undercut the larger Stone and dislodge them as it pushes up? The depth would be key. But it may be the solution to non classified mats. It may inundate the larger stones as vibrating does ? Excellent design sir. Your definitely spot on.
Hi Richard and thanks for watching. Yes, you could try that and it would work but unfortunately the problem is, that the force of the water running through the small grooves has quite a bit of force and when it hits the rock it sprays out in all directions and one of them is down. The force can easily blow out the fine black sand and gold. This type of Drop Riffle works best with material screened to about 12 mesh and smaller. Most all of the gold I work with is very tiny so this type of riffle works very well for me.
Other manufacturers have come up with mats that are wide and shallow like the Keene Miracle mat so that there is much more room for the larger rocks to rest without disturbing the fine gold. However with that design, you have to watch the water flow very carefully as it can blow out the fine gold very easily. I have found that to get the most gold, I screen all of my material down into about 4 different sizes and run each one separately but I know a lot of people don't like to do that. I have run most all of the mats on the market at one time or another and I have found that it's best to run all the larger rocks and smaller sand in different runs so that you can adjust the water flow for each one of them.
Some classification saves gold, I hate seeing a 3 in. square rock bouncing down the sluice knocking whatever's there loose.
Great test I love your sluices you make I can see the drop riffle is not going to work well for a high banker. Thanks for sharing.
Thanks Alan. I'm really liking your projects as well. Great ideas. Keep them coming. I made 6 fine gold recovery sluices and tested them this summer and believe it or not the Drop Riffle worked the best out of all the different mats and has the least amount of losses. I am currently recovering -100 to +200 gold from Alaskan Nome Beach black sand, Washington Beach black sand and Lake Michigan black sand. I have been thinking of a Drop Riffle High Banker for some time and it is a challenge for sure. However some of your latest builds have given me some ideas and I am currently working on a couple of prototypes. So I guess we'll see what we come up with over the winter.
Wonderful video! Obrigado joão From Brazil
Rei do garimpo
Thank you and thanks for watching.
That was a cool test. Got a couple of Hmmmm,s out of it.
Hi Mike and thanks for watching. About 17 years ago I started doing hundreds of tests like this to see how gold reacts to different design changes in equipment. Turns out very minor changes can make a big difference in how gold reacts. These drop riffles have been around for 200 years and I think they are still the best for catching the fine gold we have. But minor changes in them can make a difference in how well they work and rigs like this help me find the best designs.
Good demonstration, very interesting. Thanks. :-)
Hi Kevin. I appreciate you stopping by and watching.
Thank you.
Jeffrey Spradley
You're welcome Jeff. Thanks for watching. If this is of interest, I have a new one I'm working on right now that I hope I'll be able to put up in the next little while.
It's AMAZES me others NEVER do these sorts of tests. I'd verify design w LEAD, too:
Comparing input vs recovery to verify angles vs water volume & lengths
How else can they ensure that considerable amounts of Au aren't lost..?
I'd hire a hydrologist & fluid mechanical engineer for theory before optimizing & verifying design w lead.
Hi Truman and thanks for watching. I build and test many different pieces of prospecting equipment. This is just one of many tests I do on all of them and I thought some folks might be interested in it. This is my medium size gold test where I use a variety of different sizes of lead and gold. I do tests changing the water flow and angle of the sluice. Then I will run the tests all over again with very fine gold to see how it reacts with this design. At the end of each run I very carefully pan the tailings to see if there are any losses. Thus I can fine tune the design to run at its highest efficiency. I can swap out the riffles for different shape and I sized ones. I also do these tests with all the different sluice mats I’m interested in and I can make different designed mats no one else makes and test them. I take videos on each run so I can watch the action more closely over and over. This helps me go back later on to refresh my memory on how well a certain design worked.
These tests have really been helpful to me to see how different sizes of gold react to different design changes so I can build more efficient equipment. Sometimes a small change can make a very large effect on how gold is caught.
In this great video, what was the mesh you classified to? -20? and what was the water gph or speed?
what is the Angle you cut the bottom part of the riffles?
Robert T Burrows
Hi Robert and thanks for watching. The classification is about -12 /+20 mesh. I usually classify and run this first for the larger gold. Then I classify the tailings to -30, -40 and run each separately at a reduced water flow for each classification.. I'm running a 264 GPH pump with a valve on a 6" sluice. The angle was cut at 30 degrees. I found it's best to have the Riffle face that the sand hits as it goes into the trough to be straight up and down without the angle cut. The rounded nose on the slick plate where it runs into the first trough turned out to be a big "must have" as the gold follows it right down into the trough guaranteeing it ends up getting caught. I am currently working on 3 more different Riffle shapes and a little different drop Riffle sluice and I'll see if they work out well enough to put up. It's interesting that I found if you drop the water flow way down, you can run the sludge material and easily catch the -100 gold better than with the mat sluices. The troughs on these are big enough to hold the gold and black sand which I process to get more gold.
@@utahavalanch Thanks for the reply. Im an absolute believer in drop riffle boxes of any sorts. Most of our material running is onsite so we use wider longer boxes. I like the Angle of the second riffle as it tosses the heavies back and releases the lighter material to flow. Agreed on that Rounded nose as it shoves the heavies str8 down before they can float out. Id like to see a video of a longer sluice run showing all riffles working.
Robert T Burrows
I have pretty much given up stream sluicing and my big Gold Hog sluices for these as a recirculator because I can control everything so much better and get more gold. I'll try to include more of the other riffles in my next video. I usually keep all the gold in the first 2 riffles to make for less cons to process and so I usually don't pay much attention to the rest of them unless I get any gold in the tailings. I am currently using a 10x22" sluice with 3/4" deep troughs and they hold about 2oz. of material each which doesn't take long to run on the Miller Table. I'll see if I can make a longer sluice. What size and Riffle depth do you like?
Good Job. Excelent.!!!
One questions : Its design catches fine gold and black sand at the same time. ??
Yes it does. It’s one of he best designs to catch both. I have used it for many years.
If you ever make another (great) video like this ... maybe you can use food coloring to make it easier to see the little currents coupled with even the slowmo you can get off an iPhone ... bc this is excellent info.
Hi Truman. Great idea. I will see if I can do that on my next test videos and see how it works.
I use the same sump in my water table!! And a last chance inverted riffle at bottom!
Doing Thermoforming, inverted riffles are tough!!
Hi Spike and thanks for watching. Yea, I know what you mean, I tried doing those with a silicone mold for a mat. I make a lot of different molds for mats and the molds don’t always produce how you think they will.
Abs has a textured finish and negative static charge, positive Gold particles stick like fly paper!
@@spikechampkart55
Yippers, it’s good stuff alright. I thought about getting into it a few years back but it was too expensive. Good for mass production but I test different designs and concepts and so I make 30 - 40 different pieces of equipment a year for testing and so it wouldn’t work out for me. I wish there was a way to do it cheaply for one offs.
I make all my own molds, do one offs for customers too, so no limits. I built a hopper for a Trommell mold, made one, lol
you could add a kind of mesh, but not mesh, er say a line of straight wire to lift the larger stones what would slide over but the smaller particles still drop through into the dropriffle. That way your first few dropriffles are dedicated to the finest gold capture and you can adjust the shape of the later dropriffles allowing more agitation to remove the larger pebbles?
Geoff C
Hi Geoff, and thanks for watching. Yes you could do that. However I have found that it's easier to just screen the material down to a smaller size before running it and then pan out the larger size material. Some manufacturers make wide troughs about 1-1/2" wide to make enough room for the larger material as well as the small. Lots of ways to do it.
Good job! Have you tested Le Trap type riffles?
Hi Addestensfors and thanks for watching. Yes, the LeTrap sluices are very good gold catchers. The lower edge of the drop riffle is elevated a bit making it similar to these drop riffles. There are other similar types that have the bottom edge of the riffle lower and flatter much like on stairs that don’t work as quite as well and the gold catching area is much smaller. However if you keep the sluice angle flatter and the water flow slower, they will work quite well. I’m speaking of finer gold that I work with. With larger gold of course, you can have a steeper sluice angle and water flow. I prefer the deeper drop riffles like in the video as they have much deeper pockets in which to store the heavies and less chance to lose much gold. I can easily sort the gold and black sand at home on my Miller Table rather than try to do it with my sluice.
This is cool do u think a pvc hand dredge pump could clean those riffles out so you can keep feeding it?
Zion Gray
Hi Zion and thanks for watching. Yes it could but it's not necessary as they clean themselves out automatically. The sands are bouncing up and down and the lighter ones are getting thrown out when they bounce high enough to get caught in the water current and only the heaviest material like gold and black sands will remain in the trough. So you can keep feeding material into the sluice and it will get rid of the garbage automatically. That's why this is one of the best sluice designs around and has been for over 150 years.
utahavalanch it would be cool to make a way to lift up the riffles all at once while running ( if they where cubic aluminum held down like the river sluices latch system. With a flush rubber mat glued to the bottom of the box that doesnt move but acts to make the riffles water tight so nothing creeps beneith and out.) But to release the cons it into a catch tray or bucket say if it was a highbanker type. Just to make clean up n con collection faster.....i was thinking your design would be cool in aluminum but a little bit wider and longer.....i wanna try a drop riffle system. Do you know if they are better then raised riffle as in faster feeding and better collection?...to me it reminds me of a japanese design i love the look of it its almost id say art. Great job on the build and knowledge of this type of sluice
utahavalanch sorry another question...would it get less clogged up and speed up the natural drop and cleanout method if on the ends of each drop riffle it where to have a small flat extended lip or even a small raised riffle either to both tumble it faster and keep it from being level so the. Gold dont roll over amd out?
@@ziongray918
This is much easier to clean out than having removable riffles. You just turn the sluice on it's side so that the bottom and the side forms a V and then just take a can or water bottle and wash the grooves down into the bottom of the V and out the sluice.
Raised riffles are good for course gold and unclassified material but they lose the fine gold. Drop riffles are very good on the fine gold but they need to have the material classified.
@@ziongray918
The design on this is about the best I have discovered in 10 years of building and experimenting. It's a very simple design and it works very well as long as you don't over do the water flow. So if you want to build one that is simple and works very well, this design is it.
Have you run this system with straight edges to your riffles rather than undercutting them ? - and have you tried making the width of the riffles much narrower ? - at least a quarter narrower than the gap between riffles ?
Hi Mohammad and thank you for watching. Yes, I have tried the straight edges on the riffles and they work much better. Also the gap or trough between the riffles works the best if it is 3/4 inches wide. 1/2 inch doesn’t let the material work and get rid of the lighter material like it should. 1/4 inch doesn’t hardly work at all and will fill up with black sand very quickly and it won’t leave any room for the gold. Also the deck should be 3/4 inches thick by about 7 to 9 inches long. The riffles work best if they are about 5/8 inches high and 1-1/4 to 1-1/2 inches wide.
@@utahavalanch I am currently running square riffles 1/8th high and 1/8th long with the gap 3/8 wide.
The gold in my area is never 3/8ths size.
It seems to run okay catching 95% of the gold and accumulates not too much cons , but does need to be cleaned out often , which I do not mind as it only takes a minute or so , and I LOVE seeing gold often rather than digging for an hour like many prefer.
@@mohammednovalija
That will work well for you as long as you clean out often like you say. I made some silicone mats similar to yours that have riffles that are 3/16” high x 1/8” wide and 1/8” wide troughs. They are good for small runs of 1/2 - 3/4 gallons of cons or test samples. I do a lot of urban prospecting and collect 1/2 gallon samples of dirt I run across and these mats work well for that. But if I have to run more than a gallon, I use the big riffle/trough sluices.
@@utahavalanch I shall searh your channel for the silicon based mat videos.
I made my mats by using a router on some flat rubber.
Hi,thank u sir for the video,i subcribe ,greetins from Argentina.
jose hernandez
Thank you Jose and thank you for watching. Have a great day.
excellent content and design
Thank you AU Miner and thanks for watching. I do a lot of testing of different types of equipment and mats to try and understand what catches gold the best. I am currently working on several more videos of these hard riffle sluices if you are interested.
@@utahavalanch Def interested :) I think a drop riffle is far superior to a raised riffle. I've been designing and testing some of my own. I'm pondering a series of small to large drop cuts, to capture the fines and the large without classification. Very small 1/8" deep cuts, then increasing in size. My hope is the small riffle will catch the small gold and the largers gold will be caught by the nest appropriate size riffle.
@@AUMINER1
After 12 years of testing, I’ve found that the drop riffle is the best at catching gold. I primarily work with very fine gold and I have found that these large deep riffles work the best for the fine gold. The large troughs have plenty of room to catch all the heavies and I can separate the gold out of the concentrates very easily with my Miller Table or gold pan. However the riffles work best with classification. As you can see in the video, when I run -4 mesh material through the sluice, the larger rocks fill the riffles and shut the material exchange down and the gold has no where to go but out the end of the sluice.
@@utahavalanch Just tonight I was running my 60- cons through my latest test riffles. I was shocked to see a line of mirco gold in ta riffle test designs. Basically a small riffle before/on top of a larger riffle. The rest of the other riffles without that design had nothing. I reran the test with just dirty water, and a line of 500mesh blond sand was caught in the same place, and the rest of the riffles were 100% clean. I might be on to something :)
@@utahavalanch What is your opinion of the goldwell design?
To process about 700 kilograms per hour. What dimension should your design be approximately in terms of the length and width of your lock design and what height of rifles. ??
Hi Carlos. I have a gentleman down in Africa that is building one to try and handle that much material. His is 20” (50cm) wide x about 12’ (365 cm) long. That would still be pushing a sluice that size. You may need 2 of them side by side. It would be best if you could screen your material through an 8 mesh screen to keep from losing the fine gold.
I would make the riffles about 12mm high x about 20 mm wide. Make the troughs 20 - 25 mm wide.
Would love to see a clear gold pan so we can study just how fast gold stratifies.
Hi Andrew, and thanks for watching.
I and at least 3 others have done the tests. I haven’t been able to get my video out yet.
They all come to the same conclusion. Basically big gold goes to the bottom rather quickly but when it comes to small gold, 20 or 30 mesh and smaller That is a different story. Most fine gold is lighter than most anything else in the pan and won’t sink to the bottom unless there is only a very thin layer of dirt in the pan. If you classify the dirt so all material is the same size, then you will have better success but usually the black sand will be heavier and the gold will mix in with it because it has been smashed flatter and will be lighter. That is why it’s so hard to separate the fine gold from the black sand.
Hard rock university has some of the best videos on how to pan micro gold.
One of the best videos demonstrating stratification is the RUclips video…..
“Does gold sink in a gold pan”
by Allan Dampier
He also sells one of the best fine gold pans.
Allan does a good job of demonstrating how gold stratifies. Also pay close attention to his method of panning. He only works a small amount of material at a time and he keeps the material moving from side to side and always under water. This side to side motion keeps the gold at the same level in the riffles. It also keeps the material fluid and allows the gold to continue to settle deeper into the riffle and let the lighter material move out of the riffle. There is no motion to try and “Throw it out of the pan” like traditional panning. Just raise the back of the pan slightly and the lighter material will float out so the gold tends to stay in the riffle.
I only work with 40 mesh gold down to about 500 mesh. I use Allan’s panning technique to pan and then use Keith’s method of tapping to collect the invisible to the eye gold in one spot so you can see it to collect it.
You would be surprised at how much gold you can find in the micro range.
Thank you
Hi Dave. You are welcome and thanks for taking the time to watch.
excellent!!!!!
Thank you and thanks for watching.
Those gold pieces are a lot larger than -#20, does this sluice also catch -#20 gold?
Anagram Confirmed
Hi Anagram and thanks for watching. You're right. Those are some test pieces that are about 12 mesh. After I shot this video I ran a gallon of 30 mesh material and caught 1 gram of it. I didn't find any in the tailings. If you reduce the water flow to match the size material you are running you can catch down to -100 gold quite easily. The thing is with this type of sluice is that there is enough room for the gold and black sand both. I keep all black sand and process it separately and recover about a gram of gold per quart of it. The curved nose of the slick plate guides the gold down into the trough and once there it sinks to the bottom and it's very hard for it to get out.
utahavalanch that’s really impressive, thank you for the reply, sir.
how many centimeters between the rifles? how high is each riffle?
Thank you João from Brazil.
I'm not very good at the metric system :-) but I'll give it a try. The space between the riffles is 3/4 inch or 1.90 cm or 19.05 mm if my conversion program is working. The height of the riffles is the same. You can also make the riffle height 5/8 inch, 1.5 cm 16 mm if you would like but keep the distance between riffles 1.9 cm. To make sure I get all the gold, I like to have enough room in the riffles to catch all the black sand as well as the gold. If you lose any black sand, you will lose the gold that is the same weight. I like to catch it all and then separate it on my Miller Table.
@@utahavalanch thank you very much, you are a genius! God bless you brother. God bless you!
@@reidogarimpo1691
Thank you sir and God bless you as well. Hope you find lots of gold. 👍
@@utahavalanch AMEN!
@@utahavalanch Thks by this info. Rgds
Tks !
Richard Duke
Hi Richard and thanks for watching.
How hard was it to clean out ?
Hi Models and thanks for watching. It’s not too bad once you get the hang of it. You just tip it to the side and let the excess water run down the side rail and out the end of the sluice. Then you can then use a squirt bottle or something to wash each of the grooves out. I like that you can clean each groove individually and check to see how far down the sluice gold has travelled so you can adjust your water flow. You have to watch the grooves closely as they tend to hang on to the gold and you may have to pick it out with tweezers.
I think you mis-analyzed the efficiency of your riffles here. The very first spoonful of concentrate filled up the riffles that had the 45 degree cut backward, and what settled there never moved again nor did it have the dancing effect you want. It did create a nice 45 degree of concentrate forward towards the next riffle and that worked fine. But again, if the first spoonful of concentrate never moves then the function of the riffle cut backward is lost. I believe the simple right angle plain ol' straight riffle would work better but you didn't show it here.
Also, these high pieces of wood riffles which is the very thing that makes it effective to catch tiniest mesh pieces are what catches the big rocks also and which makes the project totally ineffective. Ultimately, not a good choice unless, as you suggest, the material must be classified down to very small particulate. Of course, I just rehashed what you said, ha.
I'd prefer the hands-on pan classifier with different screens down to 1/4 inch, throw it all into a take-home bucket and have a play-date at home some Saturday/Sunday afternoon. Love your vids. ciao.
Hi Trumpsahead,
This test was mainly for those who say that it’s best to cut an angle on the riffle. The first riffle was a flat cut with a slight toe cut out at the bottom to see if any of the fine gold would settle down there. As you can see the 45 deg cut creates a little different current. The flat cut creates a vortex that helps clean out the lighter material better.
If you look at the material up against the glass, you’re right it doesn’t move as there is a dead zone there. However over towards the middle you can see it is exchanging out like it should. Even though the trough looks full the water current moving through the sand turns it into a quicksand and anything heavy like gold will fall through to the bottom and stay there protected by the sand above it. Having deeper than normal troughs means that the water flow at the bottom is greatly reduced over that at the top and so It’s very hard to blow the gold out of there once it hits bottom.
Gold separation depends on weight. If all the material is the same size, gold will always sink to the bottom. So I always classify. If you have 30 mesh gold and 1/4” or 1/8” rocks and you have to set the water flow to clear out the larger rocks, the gold will go as well. If everything is classified to the same size, the rocks will get washed out before the gold.
In my testing, I don’t care what gets caught by the sluice. I only care about what gets lost so I always run the tailings through the miller table to see if there are any losses. With this video I ran a gallon bucket of 20 mesh sand and 1-1/2 grams of 30 mesh gold through 4 times at different water flows and the sluice caught every piece each time. Most in the first trough with 2 or 3 in the second. These sluices actually make a very good finishing sluice as there is plenty of room to catch the black sand and the gold unlike the mats which fill up with black sand very quickly and leave very little room for the gold to settle in.
Thanks for the comment.
love your vids 1 day i hope to go gold sluceing my self
liam cockroft
Hi Iiam and thanks for watching. I hope you will get your chance as well.
Very cool watching it at .25 speed!
FlyfishermanMike
Hi Mike, that it is. I video dozens of runs and then analyze them at all different speeds to try and find the best configurations for my sluices. Thanks for watching.
@@utahavalanch I have some questions, anyway I could get in touch with you through e-mail, if you're not too busy? I'm taking some scouts camping up AF canyon to pan and I'd like to increase our chances as much at possible. I'm looking for a for spot to pan with a place to camp nearby. Thanks!
Hi Mike, I would be glad to help you the best I can. If you could leave me an eMail address I can contact you at I can get in touch with you and erase your email addy from here. Good area to pan in.
Thinking about it, I think I know of a very good spot for you to camp right on the stream and it has a toilet.
Do it works?
Hi Aldo. Thanks for watching. Yep it works and works very well.
Do you sell these I live in Utah as well
Hi Antonio and thanks for watching. I'm sorry but I don't right now as I have so many other things going on that I have to take care of so I hate to take on more and not be able to get them out in a reasonable time. I have a lot of requests for these and so that's why I do the "How to Build" videos on them so that folks can try to try their hand at building them. They are a pretty simple design and quite easy to build.
utahavalanch ok thanks ya already on getting materials
has anyone thought of using a round riffle ?
Hi and thanks for watching. I don’t recall seeing any but someone may have tried them. I think if they worked well you would see more of them. I have square riffle mats with the top edges rounded off a bit that work very well.
@@utahavalanch it gives you the round top edge and a back cut. I have a lot of 1" and smaller bamboo. I'm just throwing out a hypothisis. What if you had say a .75" dowel shape riffle, on top of a vmat or carpet, then have a smaller say 3/8 by 1/4 ridge say a half to 2 inches in front of it.... with a gap, then repeat. I'm thinking if you have the material, you could make them fit tight and run any mat under then have then wedge in tight --- to me a combination off wood that is removable over whatever mat makes sense but I have no real experience. I also have a lot of mexican palm fronds and the stems are very strong and you can cust some interesting profiles. My thinking is that having riffles have range or shpes, sizes and patterns makes sense. I'm also thinking of having something in the 4-6 foot range. The idea I am working on is to run successive sluices 2-4 maybe that get wider and less slope as they go and have smaller and smaller grizley bars. I'm also dreaming of setting something up where you could load good amounts of material and walk away. My goal is a combination of wanting to separate out useful sizes of gravel and sand from such that are mixed in with a lot of soil. The gravel was originally from the large flat roof. There is also DG under the gravel/soil mix that I may remove some or all. Have you heard of DG having gold?
@@1FeistyKittyI’m not sure how it would work right off. The thing to do would be to build a prototype like I have here with a clear side and give it a try. I do this so I can watch how the dirt and gold reacts inside the riffles. I video tape a run or two so I can watch it over and over. I have a gram of fine gold I use in about 1/2 gallon of sand that I use to test with and that way I can check the tailings to see if there are any losses and also see where in the sluice gold collects.
Try building a basic sluice that can be easily modified and experiment with different ideas that you come up with. You may be surprised at how gold reacts to different designs.
I don’t know about the DG gold but I do a lot of urban prospecting and I have found gold in some of the most unusual places. You’d be surprised at how much gold collects on streets, large parking lots, gutters, etc. I take a shop vac to big parking lots and roads and collect quite a bit of very fine gold.
WHAT BEST SLOPE HAVE YOU OBSERVED?
Hi and thanks for watching. I usually set a starting point angle of about 10 degrees and then adjust it from there if I need to. If it’s fine gold material, I may set it closer to 7 or 8 degrees to give the fine gold a chance to settle.
@@utahavalanch Thank you very much! Great video! Rei do garimpo from Brazil
@@reidogarimpo1691 thank you and I hope you have a great day.
Too many flat spots. Needs more riffles. Small V- grooves in those flat spots will improve catching the fines.
It's too easy to clog up those big riffles with minimal water pressure..
Yes, many changes can be made to these. I have one that has large circles in the riffles as well that catches the fine gold. I have also tried the grooves on those flat spots. However if these sluices are run properly they only need about 3 or 4 riffles. My big one I ran all last season didn't ever get a piece of gold beyond the 2nd riffle. The version I'm working with now, only needs 1 or 2 riffles as 80% of the gold is caught on the slick plate and any that move on down are funneled into the first riffle where they stay. Yes, like all sluices you have to run them properly or they don't work well. I'd say that about 80% I see on the internet fall in that category. Thanks for watching.
you say your dirt is sub 20 mesh size yet your gold samples are a lot larger , a lot to be said for ( classifying ) your pay dirt. Cheers
Yippers, this isn’t paydirt. If it was it would be too dirty to see anything. This is one of my many test set ups. I have buckets of cleaned sand of all sizes I use for these tests so I can shoot video of what is going on in the sluice. That way I can watch it over and over, and speed it up or slow it down.
I use 2 grams of gold in sizes from -100 up to about 10 mesh so I can see what the different sizes do at different classifications of sand and water flow. I change the water flow and pan out each riffle separately so I can see where each gold size settles. Then I change the size makeup of the sand and start again.
All you can see in this run is the larger sizes but there is 1-1/2 grams of fine gold in there as well. I pan the tailings 2 tablespoons at a time to check for any losses. This is just 1 of 12 runs I did on these riffles and then I used the information I got from these tests to modify them and make different ones. Then I started again. I do this on all of my mats as well so that when I run paydirt through a sluice, I know exactly how to set it up to catch all the gold.
Go back and have a look what the old timers used 😂
Jim Murphy
Hi Jim, thanks for watching. Actually this is basically the same design I used over 50 years ago with my long tom. Over the years I have learned to move the riffles closer together and instead of the gaps being 12" apart they are now 3/4". This is my condensed version of my old 12 footer. This one is much easier to carry 😝 My buckets have also shrunk down to 2 gallon. Love progress. 😄 but I can't fry my eggs in these new plastic gold pans. 😢
As far as active exchange & physics are concerned. This test confirms that over burdening quickly & a large portion of the collection areas are in complete stall & ineffective. Almost the perfect bad example. Sorry for my brutal honesty.
Actually up until the -4 material was added, it was working just the way it should. The water passing over the trough creates a suction that tries to draw the sand out. The dancing sands create a quicksand that allows the gold and heavier material to drop down through to the bottom where it is protected. When the water slows or stops the sand collapses and the gold is locked into place. Just like in a crevice on bedrock in a stream. This design is over 150 years old and still has a number of companies making these today. This design wouldn't still be around and popular if it didn't work well for a lot of people.
I have been using this design in different forms for 50 years and I'm still using it and I still find it one of the best. I ran a bucket of -30 cons through this after shooting the video and it caught every piece in the top 3 riffles. I Miller Table all of my tailings to be sure.
Yes he had said and demonstrated this ; -)
Drop riffs are not worth the effort. Not enough action.
What does that mean? I'm being sincere, I am trying to figure out what to buy
Drop riffles are for Finishing, not bulk processing.
Think of it as a less tedious Miller Table.
like to see this made but in metal and with hydraulic flow. would be neat to see the hydraulic riffle action in this type of drop style model and the difference it is compared to this with the large raised riffle spaced out. love these science project style tests feels like my brains downloading some complex quantitative information.
Hi and thanks for watching. Well, maybe someone with metal working equipment will try and make something like that one of these days. I make many of these type projects to see how the gold reacts to different designs. So I work primarily with wood to keep costs down. These tests help me design more efficient pieces of equipment to catch the gold. It’s quite interesting that minor changes in a design can have a large impact on how the gold reacts.
👍💥
Thank you and thanks for watching.