Bazooka seems the best but can it be improved?!

[Master-Peter]

Hi folks,

coming from a country with nearly no gold anymore I was bitten by the gold bug some time ago. To start with I must admit I even never had a pan in hand before. I was raised and grew up in the Harz mountains and learned from my parents and grandparents there is no gold in the Harz. So I never gave it a thought or try. Nowadays the internet says (according to old documents) there is some and I'd like to go to the creeks and rivers of my childhood and give it a try. So I had a look for equipment that does the job, is affordable and does nit break the bank or back of a nearly 50 years old guy. It seems the Bazookas are state of the art.

Funny thing is I came across the original Schmidt patents when researching a method to uncover a long lost treasure ship in the phillipines for a friend of mine over there. But the time was not wasted for I'll be there in july knowing that theres gold in that hills...

But back to my thoughts on the Bazookas ...

1.) I'm wondering why they go narrower up to the end. For the top part I get the idea, because of rising pressure to get rid of the "waste". But for the fluid bed I'd expect to widen it would help heavies to settle down, because of fluid dynamics - what we all want. When I watch the pictures I cannot get the sense exept manufacturing cost.

2.) Grill clogging .... when the sluice gets narrower all the way down, the grill might as well. That might help clogging. If the grill would widen a bit from beginning it might prevent clogging.

3.) Additional drop down plate ... if the plate at the end of the grill would be bent and directed down into the whirlpool wouldn't that improve recovery by forcing all particles below waterline?

4.) makes it sense to bent the top slick plate some degrees down behind the grill to make even more goodies go down to be processed in the whirl pool?

Sidenote: If we made the whirlpool straight or expanding, a "tray" version could be made to ease cleanout for old men like me and over...

That's all my thoughts at the moment. I tried to make it as clear as a foreigner can do. In case you don't get it, feel free to blame my english.


Thanks for reading and hopefully considering...
Peter

 

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[GoldpannerDave]

Hi folks,

coming from a country with nearly no gold anymore I was bitten by the gold bug some time ago. To start with I must admit I even never had a pan in hand before. I was raised and grew up in the Harz mountains and learned from my parents and grandparents there is no gold in the Harz. So I never gave it a thought or try. Nowadays the internet says (according to old documents) there is some and I'd like to go to the creeks and rivers of my childhood and give it a try. So I had a look for equipment that does the job, is affordable and does nit break the bank or back of a nearly 50 years old guy. It seems the Bazookas are state of the art.

Funny thing is I came across the original Schmidt patents when researching a method to uncover a long lost treasure ship in the phillipines for a friend of mine over there. But the time was not wasted for I'll be there in july knowing that theres gold in that hills...

But back to my thoughts on the Bazookas ...

1.) I'm wondering why they go narrower up to the end. For the top part I get the idea, because of rising pressure to get rid of the "waste". But for the fluid bed I'd expect to widen it would help heavies to settle down, because of fluid dynamics - what we all want. When I watch the pictures I cannot get the sense exept manufacturing cost.

2.) Grill clogging .... when the sluice gets narrower all the way down, the grill might as well. That might help clogging. If the grill would widen a bit from beginning it might prevent clogging.

3.) Additional drop down plate ... if the plate at the end of the grill would be bent and directed down into the whirlpool wouldn't that improve recovery by forcing all particles below waterline?

4.) makes it sense to bent the top slick plate some degrees down behind the grill to make even more goodies go down to be processed in the whirl pool?

Sidenote: If we made the whirlpool straight or expanding, a "tray" version could be made to ease cleanout for old men like me and over...

That's all my thoughts at the moment. I tried to make it as clear as a foreigner can do. In case you don't get it, feel free to blame my english.


Thanks for reading and hopefully considering...
Peter

Peter, I will try to answer some of your questions. I did find some gold in Germany, but not much. It wasn't in Hannover either, but Bavaria, near Goldkronach and Goldmühl. It was also very tiny specs. The Bazooka will catch those specs.

The sluice narrows but the trap has basically parallel sides. That might be a good idea to make the sides expand, but you would have to work with it. You certainly don't want to reduce the pressure in the trap so that you don't get good exchange. I think it is worth trying, though. (OK, they do narrow some, but on my big miner, they aren't changing that much). I have noticed some DIY builds that are very rectangular for the fluid trap.

The grill does not narrow; it is constant width between. Causing it to widen would cause more rocks to get caught in the grill. Sometimes now you do get narrow rocks stuck in the grill. I think that would be more likely to happen with a grill that widens. (I now think you were talking about the sides of the grizzly area, not the metal wires themselves; they are parallel, but the slope on the sides is constant).

Goodyguy did have a plate beneath the grill to force the particles down as they drop into the fluid trap. I have not tried it though it seems to be a good idea that makes sense. You can check with Goodyguy or perhaps he will chime in here with his experiences.

The Bazooka is pretty easy to clean out now, even for us older guys--unless you have a 48" Miner, then it is nice to have two to do it. And it will not fit into a 5 gal bucket, so I have to use a small tub.

I hope this helps. BTW, I loved Germany and was there 7 years. Have not been there for the past 20 years however.

Dave

 

[Master-Peter]

Can one even better skin a cat?

Hi Dave thanks for the fast and kind answer. Great you loved Germany even with the little gold... Chances seem better in south Germany (Rhine valley and towards the Alps).

So I'm not that crazy to put thought in a already developed system. From all I read and some i understood I made some sketches for further discussion. This is not proved to work or even make sense. It is just my essence from reading all posts of the last few years regarding the ZOOKS and having a vast understanding of pressure and sediment (dive instructor). Please feel free to comment .

Full view


Side cut view


I hope the piccies make quite clear what I changed to the original...

 

[Vagadero]

(...)
1.) I'm wondering why they go narrower up to the end. For the top part I get the idea, because of rising pressure to get rid of the "waste". But for the fluid bed I'd expect to widen it would help heavies to settle down, because of fluid dynamics - what we all want. When I watch the pictures I cannot get the sense exept manufacturing cost.

2.) Grill clogging .... when the sluice gets narrower all the way down, the grill might as well. That might help clogging. If the grill would widen a bit from beginning it might prevent clogging.

3.) Additional drop down plate ... if the plate at the end of the grill would be bent and directed down into the whirlpool wouldn't that improve recovery by forcing all particles below waterline?

4.) makes it sense to bent the top slick plate some degrees down behind the grill to make even more goodies go down to be processed in the whirl pool?

1. Because it accelerates the water flow, thus helps to clean the fluid bed. It's an intentionally built in function. Also, is easier to put together the straight sides.
2. The grizzlies are parallel to each other.
3. May be. It's likely doesn't really matter, but complicates the design. It's always better to keep the design as simple as possible.
4 That will decrease the flow in the fluid bed and cause clog ups. See 1.

Nice drawings.

 

[Master-Peter]

I totally agree that the build would be much more pain in the ass. The straight sides are much more cheap and easy to make. From a commercial side I agree. On the other hand fluid dynamics say slow the flow and get more settled down. This is about the gold. I am not too much after manufacturing cost or ease ... I'm currently after maximum gold capture. Once we get settled down what is most effective regarding yield, we can start thinking about cutting the cost. So lets throw all experience and tryouts together to make the theoretical best sluice possible.

Lets say I'm not going to reinvent the wheel, but I'd wish to add alloy and inflated rubber to a proven technology. ;-)

Gotcha 4 the gizzlies ... my fault from picture looking and theorie.

Regarding the dropdown ... I expect it might help - and it makes sense somehow. To flowt or drown is not only a question of specific gravity, but also of shape. At least "GoldHog" say so and I can follow. So making all drown and get rid of what goes up again makes sense to me.

Thanks 4 "Nice dráwings" ... they help me to visualize...

 

[coolfinie]

Astrobouncer made a bazooka type DIY sluice which had a double flares design.
Here's the link:

 

[Vagadero]

"I totally agree that the build would be much more pain in the ass. The straight sides are much more cheap and easy to make. From a commercial side I agree. On the other hand fluid dynamics say slow the flow and get more settled down. This is about the gold. I am not too much after manufacturing cost or ease ... I'm currently after maximum gold capture. Once we get settled down what is most effective regarding yield, we can start thinking about cutting the cost. So lets throw all experience and tryouts together to make the theoretical best sluice possible.

Lets say I'm not going to reinvent the wheel, but I'd wish to add alloy and inflated rubber to a proven technology. ;-)

Gotcha 4 the gizzlies ... my fault from picture looking and theorie.

Regarding the dropdown ... I expect it might help - and it makes sense somehow. To flowt or drown is not only a question of specific gravity, but also of shape. At least "GoldHog" say so and I can follow. So making all drown and get rid of what goes up again makes sense to me.

Thanks 4 "Nice dráwings" ... they help me to visualize..."

The gold drops FAST, even in tubulent water flow.There is no need for tricks to help on it. It's not hard to estimate the falling time/velocity by calculation if you want to. Just a few inches long fluid bed is enought in a sluice.
My home made bazooka sluice boxes efficiency is about 90-95% with -100 mesh gold from unscreened material. I carefully tested them several times. In my opinion it's better to think about how to move more gravel per hour given the local circumstances than trying to recover the remaining 10-5%. That few percent doesn't really matter in small scale.
However, the recovery rates can be improved with:
-slightly enlengthen the fluid bed and divide in two.
-using a smaller screen. That will slow down the production speed.

 

[GoldpannerDave]

Hi Dave thanks for the fast and kind answer. Great you loved Germany even with the little gold... Chances seem better in south Germany (Rhine valley and towards the Alps).

So I'm not that crazy to put thought in a already developed system. From all I read and some i understood I made some sketches for further discussion. This is not proved to work or even make sense. It is just my essence from reading all posts of the last few years regarding the ZOOKS and having a vast understanding of pressure and sediment (dive instructor). Please feel free to comment .

Full view
View attachment 1150161

Side cut view
View attachment 1150162

I hope the piccies make quite clear what I changed to the original...

I like the pictures very much. I like the gentle flare out in your fluid trap. I also think the flap down might help. Try it and see.

I think your grizzly (the metal grill) should be a bit longer. I also like the slight variations you did at the entrance of the sluice, both top and bottom chambers.

Build it and see. Let know what your testing shows about your ideas.

You said something about going to the Philippines in July, so I am guessing you will be taking your DIY Bazooka with you? Good luck and the trap be full of gold! Pictures, please of that adventure?

 

[bobw53]

3.) Additional drop down plate ... if the plate at the end of the grill would be bent and directed down into the whirlpool wouldn't that improve recovery by forcing all particles below waterline?

I'm no sluice expert, but that extra bent bit there after the grizzly, trying to force the material into the fluid bed.. Would also force all the water from the slick plate down into the fluid bed...

I'm thinking that would probably really mess up the fluid bed and turn the whole contraption into a complicated single riffle sluice.

To start with I must admit I even never had a pan in hand before.

Get on e-bay and get a pan, and some paydirt to play with... Until you play with gold and see how HEAVY!!!!!(dense) it is,
you can't appreciate it... I didn't appreciate it and even thought I had struck it rich, but I couldn't keep the pyrite in the pan..
That's not a problem with real gold.

No need to FORCE gold, its HEAVY!!!! enough to move on its own...

Besides, with the slick plate, by the time your gold gets to the grizzly, it should be on the bottom, or at least quickly working its way there.
I don't see a need to force all the light stuff down into the trap, negating the work your slick plate has already done.

 

[theseeker]

Master-Peter, I like the removable fluid bed tray idea. Haven't thought through how that could be designed yet but like the idea of not having to disengage the whole sluice from it's in stream set up to remove the cons.

 

[Master-Peter]

Astrobouncer made a bazooka type DIY sluice which had a double flares design.
Here's the link:...

Yes I have seen this. It is the same idea to expand the trap(s) to catch more heavies. What I don't think to be perfect are only two tubes to agitate the "mess" on the outside.

The gold drops FAST, even in tubulent water flow.There is no need for tricks to help on it. It's not hard to estimate the falling time/velocity by calculation if you want to. Just a few inches long fluid bed is enought in a sluice.
My home made bazooka sluice boxes efficiency is about 90-95% with -100 mesh gold from unscreened material. I carefully tested them several times. In my opinion it's better to think about how to move more gravel per hour given the local circumstances than trying to recover the remaining 10-5%. That few percent doesn't really matter in small scale.
However, the recovery rates can be improved with:
-slightly enlengthen the fluid bed and divide in two.
-using a smaller screen. That will slow down the production speed.

If gold collection had nothing to do with velocity or turbulance, we'd find it all over the river, quite evenly distributed - not being the case. With our sluices, gold traps or whatever we try to mimic the situations where gold collects in a stream, behind big boulders and in cravices and cracks. These are the places with a sudden change in velocity, making the heavies drop there.

A 5-10percent gain is more worth putting some brain in once (at built) than shoveling more for a livetime. Even at our hobby scale.

Dividing the fluidbed might be a way to go. If we'd collect 90% at the first stage and 90% of the missed 10% at the second stage ... we're at 99%. If trapping 95% at the first and 95% of 5% at the second stage it sums up to 99,75% total. So double traps might be the way to go.

A smaller screen and loss in production speed might be contraproductive for the total gain ... as long as we can swing the shovel fast enough.

I like the pictures very much. I like the gentle flare out in your fluid trap. I also think the flap down might help. Try it and see.

I think your grizzly (the metal grill) should be a bit longer. I also like the slight variations you did at the entrance of the sluice, both top and bottom chambers.

Build it and see. Let know what your testing shows about your ideas.

You said something about going to the Philippines in July, so I am guessing you will be taking your DIY Bazooka with you? Good luck and the trap be full of gold! Pictures, please of that adventure?

Thanks, Dave. Sometimes a picture says more than 1000 words. Regarding the grizzly I think thats trial and error. It should be as steep as possible to sieve out what's small, but not to steep to be overcome by gravel, on the 5° to 10° angel these systems seem to run on. I might built one when I dont find improvements anymore ...

I plan to go to Mindoro for two weeks in July. But I'll have my scuba gear with me and am tight on luggage allowance already / but if a zook still fits, I'll take it there. I'll try to have a look at the locals mining there near Puerto Galera by chance.

I'm no sluice expert, but that extra bent bit there after the grizzly, trying to force the material into the fluid bed..
Would also force all the water from the slick plate down into the fluid bed...

I'm thinking that would probably really mess up the fluid bed and turn the whole contraption into a complicated single riffle sluice.


Get on e-bay and get a pan, and some paydirt to play with... Until you play with gold and see how HEAVY!!!!!(dense) it is,
you can't appreciate it... I didn't appreciate it and even thought I had struck it rich, but I couldn't keep the pyrite in the pan..
That's not a problem with real gold.

No need to FORCE gold, its HEAVY!!!! enough to move on its own...

Besides, with the slick plate, by the time your gold gets to the grizzly, it should be on the bottom, or at least quickly working its way there.
I don't see a need to force all the light stuff down into the trap, negating the work your slick plate has already done.

Neither am I ... I hope this push plate will help more than harm after reading a article at Gold Hogs page regarding the shape of heavies might help them float. A Zook is nothing more than a 1 riffle design but has forced agitation on top.

A pan from ebay is no problem here, but paydirt ?! I don't think is reasonable to ship to Germany.

The light stuff that leaves the sluice with the bigger gravel should not be forced down by this design. The, lets assume, medium weight stuff that makes it through the grizzley is to be processed by the trap and the agitation anyway...

Thank you all for taking the time and throwing in your comments. We might get the plan for "The mother of all Zooks" out of here together.

 

[Master-Peter]

Master-Peter, I like the removable fluid bed tray idea. Haven't thought through how that could be designed yet but like the idea of not having to disengage the whole sluice from it's in stream set up to remove the cons.

Here you have it ... After a day of shoveling this could ease clean out a lot ;-) I'd even like to have this to fiddle around with different tube setups until perfected. (But thats not included in my drawing yet).

 

[theseeker]

Here you have it ... After a day of shoveling this could ease clean out a lot ;-) I'd even like to have this to fiddle around with different tube setups until perfected. (But thats not included in my drawing yet).

Yes, like that idea! Thanks for the link!

 

[GoldpannerDave]

Astrobouncer made a bazooka type DIY sluice which had a double flares design.
Here's the link:

Thanks, Coolfinie, for linking this; I now remember watching it when Bazookas were first coming out and new. Now that I rewatch it, I think Astrobouncer did not have enough flow going through his sluice or the expansion angle at the trap was too much (or both). He was continually having to clean the trap area. Perhaps simply having more flow through the sluice would have fixed the problem.

I will say that I think Bazooka's approach to the grizzly and trap area are superior. While harder to do for DIY sluices, the parallel metal wires are better than hardware cloth in that they impede the flow less. Then they have a rear slick plate after the grizzly to let the rocks wash off easier. If your entire trap area is covered by hardware cloth, that slows the water flow also. I am not in any way slamming Astrobouncer or others who have contributed their DIY designs (djpitr and Goodyguy immediately come to mind) because I appreciate so much their sharing of their ideas and projects. Of course if you can get plenty of flow, I don't think any of that matters much.

Most folks like 3 tubes in the trap instead of 2. Sluice lee has a thread on the Frankenzooka with a clear sluice plate over the trap which many of us here like. You can see 3 tubes in the trap in his pictures.

 

[fowledup]

I like the knockdown intake bar, it eliminates any possiblilty of surface tension floating out fine gold. I don't understand the gain of the exhaust exit ramp angled piece, seems as tho it is taking up fluid bed space as they clean out very well as is with a flat wall. The grizzlies- I would like to see one with closely spaced grizzlies as flat as the slick plate, for fine gold, in conjunction with that I'd extend the discharge end of the slick plate past the fluid bed exhaust and install a nugget trap, boil box secondary fluid bed off the top discharge. A drop away fluid bed with latches would be a fairly simple thing to accomplish. I would love to build the above mods for a custom dredge set up.

 

[Master-Peter]

... Most folks like 3 tubes in the trap instead of 2. Sluice lee has a thread on the Frankenzooka with a clear sluice plate over the trap which many of us here like. You can see 3 tubes in the trap in his pictures.

I planned 4 Pcs, about 1" each.

I like the knockdown intake bar, it eliminates any possiblilty of surface tension floating out fine gold. I don't understand the gain of the exhaust exit ramp angled piece, seems as tho it is taking up fluid bed space as they clean out very well as is with a flat wall. The grizzlies- I would like to see one with closely spaced grizzlies as flat as the slick plate, for fine gold, in conjunction with that I'd extend the discharge end of the slick plate past the fluid bed exhaust and install a nugget trap, boil box secondary fluid bed off the top discharge. A drop away fluid bed with latches would be a fairly simple thing to accomplish. I would love to build the above mods for a custom dredge set up.

I included the small box at the end as a dead end for the tubes to reconnect. I have seen a youtube video with someone mention backconnecting the tubes would equalize the pressure. I'm not sure if that makes any sense. Besides I thaught about adding some port to the box for cleaning and to connect a hose to run the system as highbanker with the tubes bottomfed. So if one would put the system slightly angeled on a stand, attach a water hose to the box - as long as water flows over the inletside there is consistent pressure in the agitation chamber.

For a dredge system a nugget trap behind the discharge might collect some, if there were some.

 

[Master-Peter]

Master-Peter, I like the removable fluid bed tray idea. Haven't thought through how that could be designed yet but like the idea of not having to disengage the whole sluice from it's in stream set up to remove the cons.

One more 4 you

 

[arizau]

Hi Dave thanks for the fast and kind answer. Great you loved Germany even with the little gold... Chances seem better in south Germany (Rhine valley and towards the Alps).

So I'm not that crazy to put thought in a already developed system. From all I read and some i understood I made some sketches for further discussion. This is not proved to work or even make sense. It is just my essence from reading all posts of the last few years regarding the ZOOKS and having a vast understanding of pressure and sediment (dive instructor). Please feel free to comment .

Full view
View attachment 1150161

Side cut view
View attachment 1150162

I hope the piccies make quite clear what I changed to the original...

I originally incorporated the down draft feature in my zook but after thinking about it I took it out since I thought it might promote premature scouring of the upper layer of suspended material and not give it a chance to settle and fluid bed action to take place before it was swept out of the box. I then put in a perpendicular wicker, the top of which is level with the slick plate and the lip of the exit port, and sits on top of the tubes. All but the lightest of material will drop some as it enters the box then be suddenly stopped by the wicker. With forward momentum stopped the fluid bed should take care of displacement and sorting and ultimate rejection of waste material while gold and other heavy material settles and is retained. With no real way to test I'm not sure if it actually improves the performance but the science seems to be sound to my way of thinking.
Good Luck

 

[Master-Peter]

I originally incorporated the down draft feature in my zook but after thinking about it I took it out since I thought it might promote premature scouring of the upper layer of suspended material and not give it a chance to settle and fluid bed action to take place before it was swept out of the box. I then put in a perpendicular wicker, the top of which is level with the slick plate and the lip of the exit port, and sits on top of the tubes. All but the lightest of material will drop some as it enters the box then be suddenly stopped by the wicker. With forward momentum stopped the fluid bed should take care of displacement and sorting and ultimate rejection of waste material while gold and other heavy material settles and is retained. With no real way to test I'm not sure if it actually improves the performance but the science seems to be sound to my way of thinking.
Good Luck

Thanks Arizau for jumping in. I do hope the feature might help more than hurt for it is used in the underflow sluices and seems to work quite good there at least. I'dont expect it to interfere to much with the forced agitation from below.

The major problem with all our ideas, inventions and thoughts is that there is about no way (or lack of funds) to run consistent test against each other on the small scale.

 

[arizau]

If you think about it, a wicker does much the same thing as is demonstrated in the video. I think the advantage of a wicker in a zook configuration is that it allows free flow of water and lighter material over it while the heavy material settles or goes under it while it is deep in the fluid bed.

I think induced water speed/force beneath the natural water level does promote scouring by banking the material at the exit end of the box thus limiting fluid bed activity mostly only to that end of the box.

I guess we may have to agree to disagree.

Good luck.