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my sluice box build

dfrew		Posted : Monday, 2 September 2013 10:30:18 PM(UTC)
Rank: Gold Flake Groups: Registered Joined: 5/12/2012(UTC) Posts: 12 Location: auckland Thanks: 3 times		If I can figure out how to put pics up i will put the progress of my sluice box up. File Attachment(s): photo-13.JPG

gjj109		Posted : Monday, 2 September 2013 11:38:04 PM(UTC)
Rank: Gold Ingot Medals: Groups: Registered Joined: 14/03/2011(UTC) Posts: 464 Location: Thames Thanks: 217 times Was thanked: 194 time(s) in 115 post(s)		That's a tidy looking unit, but won't the box up the front fill up with rocks quite quickly?

dfrew		Posted : Tuesday, 3 September 2013 9:43:26 AM(UTC)
Rank: Gold Flake Groups: Registered Joined: 5/12/2012(UTC) Posts: 12 Location: auckland Thanks: 3 times		The top box is on a hinge I have made it so that you don't have to classify the material it can be shovelled into the front of the box and will be washed there so hopefully no chance of loosing any gold of the rocks then the top is flipped and rocks cleared out to the side Edited by user Tuesday, 3 September 2013 9:49:36 AM(UTC) \| Reason: Not specified

gjj109		Posted : Tuesday, 3 September 2013 5:34:28 PM(UTC)
Rank: Gold Ingot Medals: Groups: Registered Joined: 14/03/2011(UTC) Posts: 464 Location: Thames Thanks: 217 times Was thanked: 194 time(s) in 115 post(s)		I am assuming you have an inch or so of water flowing through the sluice and the box sits above this water flow. To wash the gravel in the box will you have to tip water into the box or do you have another way of washing the gravel? Also, if you tip the larger rocks to one side, after a few bucketfuls, you will then have to shovel these larger rocks out of the way. Tipping the box full of rocks may also tend to move the sluice. A simpler method would just be to preclassify the material to say everything bigger than an inch, throw it all into the sluice and let it wash through. Much faster and a lot less work. I must say though, the sluice does look a neat piece of work.

jafa		Posted : Tuesday, 3 September 2013 8:43:20 PM(UTC)
Rank: Gold Ingot Groups: Registered Joined: 22/11/2011(UTC) Posts: 134 Location: auckland Thanks: 22 times Was thanked: 23 time(s) in 19 post(s)		Good work nice sluice i like the idea of the hinge about the only fault could possibly be not enough holes to classify quickly maybe even some expanded mesh bolted to the bottom instead of drilled holes to really open it up.
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garrymac		Posted : Tuesday, 3 September 2013 9:36:42 PM(UTC)
Rank: Gold Nugget Groups: Registered Joined: 3/03/2011(UTC) Posts: 84 Location: dunedin Thanks: 26 times Was thanked: 26 time(s) in 19 post(s)		great looking sluice box, ive never bothered with sizing material, what ever is on the shovel goes down the sluice. All the gold has stayed in the top four riffles

dfrew		Posted : Tuesday, 3 September 2013 10:45:26 PM(UTC)
Rank: Gold Flake Groups: Registered Joined: 5/12/2012(UTC) Posts: 12 Location: auckland Thanks: 3 times		Hi all Did a bit of work over a few beers tonight. The idea behind this thing is the water flows into the top,you shovel all material into the top where all the holes are and washing all small material down through to the when I get it ribbed matt and then to the expanded mesh when I get it and hopefully leaves the gold in the miners moss.I'm guessing I will have to use a brush or something to move the unclassified material around to make sure its washed properly before tipping it over the side.Tonight I added a few gap seals the handle and riveted the hinge on. Edited by user Tuesday, 3 September 2013 10:54:38 PM(UTC) \| Reason: Not specified File Attachment(s): photo-15.JPG

gjj109		Posted : Tuesday, 3 September 2013 11:41:32 PM(UTC)
Rank: Gold Ingot Medals: Groups: Registered Joined: 14/03/2011(UTC) Posts: 464 Location: Thames Thanks: 217 times Was thanked: 194 time(s) in 115 post(s)		I think the material in the box will require considerable agitation to ensure the gold passes through the holes before you tip the material over the side. Jafa's idea of replacing the bottom plate with expanded mesh would be a move in the right direction. I think your box idea will work only where the gold is able to move freely within the gravel. The gold on the Coromandel is usually found within a clay layer. I think the box idea will make the sluice slow to operate and the gold has limited opportunity to break free from the clay matrix. Also, if I view your picture correctly, water will only flow over the riffles when there is no material in the box. If you removed the box and had a normal sluice, I think your gravel throughput would be greater with less effort. However the only way to find out is take it to a creek and shovel that gravel in. Any creek will do. It doesn't need to be in gold bearing country, you want to see if it will separate the material.

dfrew		Posted : Wednesday, 4 September 2013 12:26:59 AM(UTC)
Rank: Gold Flake Groups: Registered Joined: 5/12/2012(UTC) Posts: 12 Location: auckland Thanks: 3 times		Thanks for your suggestion there is plenty of room for modification on this thing, will be a bit of trial and error I'm sure and its good everyone is giving me input so that I know where to go if this thing doesn't work as planed so feel free to comment.

gjj109		Posted : Wednesday, 4 September 2013 5:41:50 PM(UTC)
Rank: Gold Ingot Medals: Groups: Registered Joined: 14/03/2011(UTC) Posts: 464 Location: Thames Thanks: 217 times Was thanked: 194 time(s) in 115 post(s)		Just a couple of other points: When you tip the rocks out of the box, won't this let a sudden rush of water run through the riffles? You really want a steady controlled flow. Why don't you replace the hinge rivets with bolts. Then, if the box isn't working too well, you can quickly remove it. You can always re-rivet it another day if you consider it to be a superb idea.

dfrew		Posted : Wednesday, 4 September 2013 11:36:25 PM(UTC)
Rank: Gold Flake Groups: Registered Joined: 5/12/2012(UTC) Posts: 12 Location: auckland Thanks: 3 times		I'm hoping that flow of water wont be disrupted to much as the water should be flowing through the grate freely, thinking about adding a few slots to the grate so that there is no corners or edges.The rivets were easy as I'm an aircraft engineer. Will take a battery drill for test runs to add extra holes or remove grate. File Attachment(s): photo-14.JPG

dfrew		Posted : Wednesday, 4 September 2013 11:54:46 PM(UTC)
Rank: Gold Flake Groups: Registered Joined: 5/12/2012(UTC) Posts: 12 Location: auckland Thanks: 3 times		There is already many more holes in the grate than the last pic.

simon		Posted : Thursday, 5 September 2013 9:46:45 AM(UTC)
Rank: Gold Ingot Groups: Registered Joined: 7/01/2011(UTC) Posts: 789 Location: Central Otago Thanks: 33 times Was thanked: 239 time(s) in 150 post(s)		My two cents: get some pre punched plate. beats drilling millions of holes. there's not near enough. forget about classifying. you need to move as much paydirt as possible. shovelfuls at a time. you might be better building a high banker. then you could build some grizzly bars over the hopper. thus all bigger rocks will not enter the box. you would need to be able to wash said rocks, in case gold adhered to them, but also to get the finers particles moving thru the box. a highbanker would mean you are not confined to the water channel and its varying flow. you would need a pump or bilge and battery to run it. as pointed out above you will need a constant flow of water for best results. i think this current design will be a bit cumbersome with the top bit not letting the water flow through. its all a bit of trial and error building your own stuff.
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Cleggie		Posted : Thursday, 5 September 2013 12:01:56 PM(UTC)
Rank: Gold Nugget Groups: Registered Joined: 24/03/2012(UTC) Posts: 88 Location: Christchurch Thanks: 88 times Was thanked: 59 time(s) in 31 post(s)		Hi dfrew, you have made a nice start and I like your thinking on this one... however the preclassifier as others have noted has some problems. Getting rid of the large stones is a good idea as they can sit in the sluice box disrupting the flow and potentially causing gold to be lost in the tailings. Your hopper box needs to look more like a grizzly with a totally open bottom, expanded mesh would do with maybe some bars across to stop the mesh sagging. The riffles in your sluice look a lot like my first sluice. Hard to tell from the pics you posted but you could end up with the same problems that I had. The sluice became packed with sand and fine gravels behind the riffles leaving nowhere for the gold to come into contact with the miners moss. The other problem I had was removing the riffles to clean the matting. I found the fine silt and sand had worked it's way along the sides of the riffle bar wedging it tight in the sluice box. So make sure you have a bit of clearance and if the sluice packs up with gravels maybe make the riffles smaller. The performance of your sluice is determined by the volume and velocity of the water flow. The water needs to be flowing fast enough to make material behind your riffles dance and over a short period of time wash the lighter sands and gravels out leaving only the heavies, black sand and gold. So think of your sluice as the mark I version. You are not going to know how well it works or not until you have a play with it, then back to the man cave for mark II or III. Good luck, have fun, Ken.

dfrew		Posted : Thursday, 5 September 2013 9:58:12 PM(UTC)
Rank: Gold Flake Groups: Registered Joined: 5/12/2012(UTC) Posts: 12 Location: auckland Thanks: 3 times		Thanks Ken Yes there will be a few marks and this is the info I need. The what to look for, there is a few bits coming and I will see what I can come up with for the new classifier. Cheers

dfrew		Posted : Thursday, 5 September 2013 11:14:15 PM(UTC)
Rank: Gold Flake Groups: Registered Joined: 5/12/2012(UTC) Posts: 12 Location: auckland Thanks: 3 times		If I put bars in the upper box what I don't want to happen is once the front is clear of gravel and clay the water run freely down the sluice.I want all the rocks washed I think its going to be bit of a game to find the right amount of resistance for the water and I dont want to use pumps or dredges.

simon		Posted : Friday, 6 September 2013 9:28:19 AM(UTC)
Rank: Gold Ingot Groups: Registered Joined: 7/01/2011(UTC) Posts: 789 Location: Central Otago Thanks: 33 times Was thanked: 239 time(s) in 150 post(s)		Hi again, As Cleggie pointed out above most sluice boxes get modified here and there as they show there flaws or ways you could improve them. I think if you don't want to use a bilge pump or motor you may have to look at a flare on the top of the sluice. this will gather more water. there are generally two types of flare. the proper flare extension that bolts onto the head of a standard sluice, and the second is merely a sort of makeshift flare, where they bend over the top of the sluicebox sides to catch a bit more flow. you can see this on the keene sluice boxes, models A52 is the real deal, amd model A51 i think it is, is the bent side type. i built a hopper contraption for my sluicebox with flare and had similar problems to you. the intention was to connect to a bilge. eventually got the pump right and the pipes all good with enough flow but you still need to get rid of the larger rocks. i don't like wasting time classifying so i wanted a grizzly type setup. old shelves from fridges at the dump are cheap grizzly bars! anyhow, the key issue was the grizzly bars need to face a certain way so the tailings dumps down the ground at the head of the sluice. coming of sideways meant every 2 seconds you have to move the tailings out of the way. the eventuality was the sluice had to become a high banker., which is much more versatile as you don't have to be in the water. at the end of the day you have to decide whether it is the sluice or highbanker that needs built. i found it tough trying to gather water via a flare, whilst trying to have a grizzly filtering out the big rock in essentially the same head area of the sluice. A mate had the great idea of placing a section of punched steel plate in his sluice, with grizzly type wires stopping the big rocks going under it. sort of like they have in dredge sluiceboxes. seemed to work a treat as the water makes the rocks slide off this. so it is sort of a two level sluice. the lower deck is standard, the punch plate sits a couple of inches above.
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Cleggie		Posted : Friday, 6 September 2013 9:33:37 AM(UTC)
Rank: Gold Nugget Groups: Registered Joined: 24/03/2012(UTC) Posts: 88 Location: Christchurch Thanks: 88 times Was thanked: 59 time(s) in 31 post(s)		Hi, The way I see it is you have two options for washing the rocks and breaking up the clay. 1/ Use your shovel to scoop water and wash the rocks sitting in your hopper. If you do this you will likely need a damping baffle in your sluice box but you will be able to run more material than option two. 2/ Do away with the hopper and classify through a garden sieve into a bucket. That way you can give it a good shaking and loosen everything before running it through your sluice. This method will slow down your through put and make more work for you. It really depends on the type of paydirt you run through your sluice and how hard you are prepared to work at it. Cheers, Ken

simon		Posted : Friday, 6 September 2013 10:15:38 AM(UTC)
Rank: Gold Ingot Groups: Registered Joined: 7/01/2011(UTC) Posts: 789 Location: Central Otago Thanks: 33 times Was thanked: 239 time(s) in 150 post(s)		"It really depends on the type of paydirt you run through your sluice and how hard you are prepared to work at it." Ken has summed it up. i would be looking at how big a river are you working. this may affect your flows etc. no point having a little piddly sluice if you've got the power of say the shotover to play with. if its just a small stream there may be little room for a massive keene A52 type sluice box. And a very low flow may force even those that hate classifying with sieves into having to do so. As ken said above the key is what material are you moving. if its something tough like clays and conglomerates you are going to have to get the design spot on to break it all up, and you will need loads of water power. If it's just loose material it is a lot easier. Each river is sort of unique. for example around here one waterway may be loaded with heavies such as hotrocks and black sands that will try and clog your box it setup is poor. the next waterway over the ridge may be nearly completely free of black sands. a good example here is also the abundance of small cobbles that are flattish as opposed to round. i've seen the likes of keene hoppers struggle with such rocks to the point the factory design needs changed so these flat cobbles don't lodge and stay stuck in the bars, thus clogging it all up. at the end of the day the more dirt you move the more likely you will get more gold. so your best bet is being able to shovel flat stick into a good sized sluice. with a big flow through a box you can keep most material moving through. i simple pull off the shovel sized rocks as i dig, let the rest go thru, and either use a hand or rake to keep the box clear of stuck stuff. the right setup and even the fines remain. having a flare also gives you somewhere to dump a good amount of material not just over the top couple of riffles but on the neck of the flare also. so while you are off digging again the water will slowly bring it all down into the sluice. get it right and it works. you just have to make sure you don't load it so much it stuffs up the constant flow of water too much. i know a lot of people are worried about losing some gold. sometimes you just have to weigh up losing some versus shovelling heaps more roughly and perhaps doing better. a good trick is to occassionally test the tailings that fall out of the sluice to check on such possible losses. just remember to dig good into the tailings you are testing as the gold has probably settle down quite a lot in such loose material worth water flowing over it.
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